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Visualizing the gibbs models / Kenneth R. Jolls in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 4973–4987 Titre : Visualizing the gibbs models Type de document : texte imprimé Auteurs : Kenneth R. Jolls, Auteur ; Daniel C. Coy, Auteur Année de publication : 2008 Article en page(s) : p. 4973–4987 Note générale : Bibliogr. p. 4976-4987 Langues : Anglais (eng) Mots-clés : Thermodynamic functionsPure systemsBinary systemsTernary systemsComputer graphics Résumé : Images of thermodynamic fundamental and state functions for pure, binary, and ternary systems have been created using high-performance computer graphics. Results were obtained from integrations of the Peng−Robinson equation, using standard heat-capacity data and common mixing rules. The Legendre-transform basis of the various thermodynamic coordinate systems is demonstrated, and the agreement between those geometries and the relevant criteria for thermodynamic stability is noted. The capacity of the images to convey the nature and utility of complex thermodynamic quantities is used as an argument for greater emphasis on visualization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071277b [article] Visualizing the gibbs models [texte imprimé] / Kenneth R. Jolls, Auteur ; Daniel C. Coy, Auteur . - 2008 . - p. 4973–4987. Bibliogr. p. 4976-4987 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 4973–4987 Mots-clés : Thermodynamic functionsPure systemsBinary systemsTernary systemsComputer graphics Résumé : Images of thermodynamic fundamental and state functions for pure, binary, and ternary systems have been created using high-performance computer graphics. Results were obtained from integrations of the Peng−Robinson equation, using standard heat-capacity data and common mixing rules. The Legendre-transform basis of the various thermodynamic coordinate systems is demonstrated, and the agreement between those geometries and the relevant criteria for thermodynamic stability is noted. The capacity of the images to convey the nature and utility of complex thermodynamic quantities is used as an argument for greater emphasis on visualization. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071277b

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Toward a quantitative theory of ultrasmall liquid droplets and vapor / Zhidong Li in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 4988–4995 Titre : Toward a quantitative theory of ultrasmall liquid droplets and vapor : liquid nucleation Type de document : texte imprimé Auteurs : Zhidong Li, Auteur ; Jianzhong Wu, Auteur Année de publication : 2008 Article en page(s) : p. 4988–4995 Note générale : Bibliogr. p. 4994-4995 Langues : Anglais (eng) Mots-clés : Small systems -- thermodynamic properties Nonmean-field density Ultrasmall liquid dropletsLennard-Jones model Résumé : Thermodynamic properties of small systems can be drastically different from those corresponding to their macroscopic counterparts due to the surface and fluctuation effects. While the equations of state for macroscopic systems are well advanced, quantitative predictions of the structural and thermodynamic properties of small systems from a molecular perspective remain a daunting challenge. This article illustrates applications of a nonmean-field density functional theory to two types of ultrasmall liquid droplets: one is stabilized in a container of finite size and the other is unstable as appeared during vapor—liquid nucleation. For small systems of simple fluids represented by the Lennard-Jones model, theoretical predictions are compared with results from molecular simulations for the microscopic structure, the droplet size, and the free energy of formation over a broad range of conditions. The numerical agreement of theory with simulation data is comparable to that for the corresponding macroscopic systems. While the Tolman length, a correlation of curvature on surface tension, is negligible at least for small droplets of simple fluids, the vapor—liquid interfacial tension declines with the droplet size approximately proportional to the Gaussian curvature. Surprisingly, the Laplace equation for pressure change across a curved surface remains accurate even for a liquid droplet with the radius only a few times the molecular diameter. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070578i [article] Toward a quantitative theory of ultrasmall liquid droplets and vapor : liquid nucleation [texte imprimé] / Zhidong Li, Auteur ; Jianzhong Wu, Auteur . - 2008 . - p. 4988–4995. Bibliogr. p. 4994-4995 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 4988–4995 Mots-clés : Small systems -- thermodynamic properties Nonmean-field density Ultrasmall liquid dropletsLennard-Jones model Résumé : Thermodynamic properties of small systems can be drastically different from those corresponding to their macroscopic counterparts due to the surface and fluctuation effects. While the equations of state for macroscopic systems are well advanced, quantitative predictions of the structural and thermodynamic properties of small systems from a molecular perspective remain a daunting challenge. This article illustrates applications of a nonmean-field density functional theory to two types of ultrasmall liquid droplets: one is stabilized in a container of finite size and the other is unstable as appeared during vapor—liquid nucleation. For small systems of simple fluids represented by the Lennard-Jones model, theoretical predictions are compared with results from molecular simulations for the microscopic structure, the droplet size, and the free energy of formation over a broad range of conditions. The numerical agreement of theory with simulation data is comparable to that for the corresponding macroscopic systems. While the Tolman length, a correlation of curvature on surface tension, is negligible at least for small droplets of simple fluids, the vapor—liquid interfacial tension declines with the droplet size approximately proportional to the Gaussian curvature. Surprisingly, the Laplace equation for pressure change across a curved surface remains accurate even for a liquid droplet with the radius only a few times the molecular diameter. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070578i

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Butadiene purification using polar solvents / Paul M. Mathias in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 4996–5004 Titre : Butadiene purification using polar solvents : analysis of solution nonideality using data and estimation methods Type de document : texte imprimé Auteurs : Paul M. Mathias, Auteur ; J. Richard Elliott, Auteur ; Andreas Klamt, Auteur Année de publication : 2008 Article en page(s) : p. 4996–5004 Note générale : Bibliogr. p. 5003-5004 Langues : Anglais (eng) Mots-clés : Butadiene -- purificationButadiene solventsMolecular simulation Résumé : The classical problem of 1,3-butadiene recovery from steam cracker C4 hydrocarbons is reconsidered using modern tools of quantum mechanics and molecular simulation. The effectiveness of N,N-dimethylformamide (DMF) and acetonitrile (ACN) to act as extractive-distillation solvents is explored with an emphasis on the predictive capability of various models. The quantum mechanical method of interest is the COSMO-RS method. The chosen molecular simulation method is the SPEADMD model. These methods are compared to conventional methods such as UNIFAC and “thermodynamic intuition”. The COSMO-RS method is found to predict the trends of infinite-dilution activity coefficients quantitatively, but requires a systematic empirical correction to provide accuracy comparable to UNIFAC. It is noted that the COSMO-RS method has a special capability to predict subtle trends. The SPEADMD model is found to provide unique qualitative insights, but requires empirical refinement of the interaction-potential models that is similar to the regression of UNIFAC parameters. This work is intended to serve as an objective framework to evaluate tools—traditional and modern—to predict solution nonideality. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070774p [article] Butadiene purification using polar solvents : analysis of solution nonideality using data and estimation methods [texte imprimé] / Paul M. Mathias, Auteur ; J. Richard Elliott, Auteur ; Andreas Klamt, Auteur . - 2008 . - p. 4996–5004. Bibliogr. p. 5003-5004 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 4996–5004 Mots-clés : Butadiene -- purificationButadiene solventsMolecular simulation Résumé : The classical problem of 1,3-butadiene recovery from steam cracker C4 hydrocarbons is reconsidered using modern tools of quantum mechanics and molecular simulation. The effectiveness of N,N-dimethylformamide (DMF) and acetonitrile (ACN) to act as extractive-distillation solvents is explored with an emphasis on the predictive capability of various models. The quantum mechanical method of interest is the COSMO-RS method. The chosen molecular simulation method is the SPEADMD model. These methods are compared to conventional methods such as UNIFAC and “thermodynamic intuition”. The COSMO-RS method is found to predict the trends of infinite-dilution activity coefficients quantitatively, but requires a systematic empirical correction to provide accuracy comparable to UNIFAC. It is noted that the COSMO-RS method has a special capability to predict subtle trends. The SPEADMD model is found to provide unique qualitative insights, but requires empirical refinement of the interaction-potential models that is similar to the regression of UNIFAC parameters. This work is intended to serve as an objective framework to evaluate tools—traditional and modern—to predict solution nonideality. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070774p

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Two-dimensional self-assembly of similarly charged granular particles / S. C. Wu in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5005–5015 Titre : Two-dimensional self-assembly of similarly charged granular particles Type de document : texte imprimé Auteurs : S. C. Wu, Auteur ; D. T. Wasan, Auteur ; A. D. Nikolov, Auteur Année de publication : 2008 Article en page(s) : p. 5005–5015 Note générale : Bibliogr. p. 5014-5015 Langues : Anglais (eng) Mots-clés : Particle surface coverage -- granular assemblies Monte Carlo simulation Résumé : We present results of our experimental study on the effect of particle surface coverage (density) on the evolution of packing structure in charged granular assemblies in a two-dimensional (2D) geometry. Steel particles were charged by rubbing them with the bottom surface of a polystyrene box. We conducted a Monte Carlo simulation study via the interparticle interaction of the dipole repulsion. The resulting radial distribution functions, bond orientation correlation functions, and 2D pressure isotherm approximate the experimental data well. The particle potential of the mean force changes from repulsion only at a low particle coverage fraction of 0.01 to oscillation between repulsion and attraction at higher coverage fractions due to the collective particle interactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0708125 [article] Two-dimensional self-assembly of similarly charged granular particles [texte imprimé] / S. C. Wu, Auteur ; D. T. Wasan, Auteur ; A. D. Nikolov, Auteur . - 2008 . - p. 5005–5015. Bibliogr. p. 5014-5015 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5005–5015 Mots-clés : Particle surface coverage -- granular assemblies Monte Carlo simulation Résumé : We present results of our experimental study on the effect of particle surface coverage (density) on the evolution of packing structure in charged granular assemblies in a two-dimensional (2D) geometry. Steel particles were charged by rubbing them with the bottom surface of a polystyrene box. We conducted a Monte Carlo simulation study via the interparticle interaction of the dipole repulsion. The resulting radial distribution functions, bond orientation correlation functions, and 2D pressure isotherm approximate the experimental data well. The particle potential of the mean force changes from repulsion only at a low particle coverage fraction of 0.01 to oscillation between repulsion and attraction at higher coverage fractions due to the collective particle interactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0708125

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A molecular theory of the activity coefficients and their reference fugacities at the supercritical state / Stephen G. Martz in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5016–5022 Titre : A molecular theory of the activity coefficients and their reference fugacities at the supercritical state Type de document : texte imprimé Auteurs : Stephen G. Martz, Auteur ; Lloyd L. Lee, Auteur Année de publication : 2008 Article en page(s) : p. 5016–5022 Note générale : Bibliogr. p. 5022 Langues : Anglais (eng) Mots-clés : Mixtures -- activity coefficient Molecular theory Ornstein-Zernike equations Résumé : We take advantage of the recent advances in statistical mechanics on mixtures to examine a century-old problem in solution thermodynamics, specifically for the popular activity coefficient model, with regard to the absence of a standard state for the noncondensable gases in the mixture. This defect is traced back to the excess Gibbs free energy formalism where insistence on a pure liquid-state reference fluid is incorporated. By examining the molecularly derived counterparts, we propose a new division of the component chemical potential along the line of the molecular theory. A new definition of a reference fugacity and that of a molecular-inspired activity coefficients are formulated to cure this defect. We employ the Ornstein—Zernike equations to actually evaluate the molecular activity coefficients for a mixture of methane and n-pentane. The system temperature is 444 K. Thus, methane is the suprecritical component and does not fit into the classical activity coefficient model. We demonstrate that the molecular activity coefficients of methane and n-pentane can be evaluated and do not suffer nonexistence. Furthermore, these values are used to determine the dew point and bubble point of the mixture. The results compare favorably with the experimental data of Sage and Lacey. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071216d [article] A molecular theory of the activity coefficients and their reference fugacities at the supercritical state [texte imprimé] / Stephen G. Martz, Auteur ; Lloyd L. Lee, Auteur . - 2008 . - p. 5016–5022. Bibliogr. p. 5022 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5016–5022 Mots-clés : Mixtures -- activity coefficient Molecular theory Ornstein-Zernike equations Résumé : We take advantage of the recent advances in statistical mechanics on mixtures to examine a century-old problem in solution thermodynamics, specifically for the popular activity coefficient model, with regard to the absence of a standard state for the noncondensable gases in the mixture. This defect is traced back to the excess Gibbs free energy formalism where insistence on a pure liquid-state reference fluid is incorporated. By examining the molecularly derived counterparts, we propose a new division of the component chemical potential along the line of the molecular theory. A new definition of a reference fugacity and that of a molecular-inspired activity coefficients are formulated to cure this defect. We employ the Ornstein—Zernike equations to actually evaluate the molecular activity coefficients for a mixture of methane and n-pentane. The system temperature is 444 K. Thus, methane is the suprecritical component and does not fit into the classical activity coefficient model. We demonstrate that the molecular activity coefficients of methane and n-pentane can be evaluated and do not suffer nonexistence. Furthermore, these values are used to determine the dew point and bubble point of the mixture. The results compare favorably with the experimental data of Sage and Lacey. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071216d

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Self-assembly of nanoparticle mixtures in diblock copolymers / Marek Maly in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5023–5038 Titre : Self-assembly of nanoparticle mixtures in diblock copolymers : multiscale molecular modeling Type de document : texte imprimé Auteurs : Marek Maly, Auteur ; Paola Posocco, Auteur ; Sabrina Pricl, Auteur ; Fermeglia, Maurizio, Auteur Année de publication : 2008 Article en page(s) : p. 5023–5038 Note générale : Bibliogr. p. 5038 Langues : Anglais (eng) Mots-clés : Copolymers Nanoparticles Hybrid materialsDissipative particle dynamics Résumé : Mixing microphase-separating diblock copolymers and nanoparticles can lead to the self-assembly of organic/inorganic hybrid materials that are spatially organized on the nanometer scale. Controlling particle location and patterns within the polymeric matrix domains remains, however, an unmet need. Computer simulation of such systems constitutes an interesting challenge since an appropriate technique would require the capturing of both the formation of the diblock mesophases and the copolymer−particle and particle−particle interactions, which can affect the ultimate structure of the material. In this paper we discuss the application of dissipative particle dynamics (DPD) to the study of the distribution of nanoparticles in lamellar and hexagonal diblock copolymer matrices. The DPD parameters of the systems were calculated according to a multiscale modeling approach, i.e., from lower scale (atomistic) simulations. The results show that the positioning and ordering of the nanoparticles depend on several different factors, including their covering type and volume fraction. Also, the geometric features of the matrix are found to exert an influence on the particle location and pattern. The overall results provide molecular-level information for the rational, a priori design of new polymer−particle nanocomposites with ad hoc, tailored properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071311m [article] Self-assembly of nanoparticle mixtures in diblock copolymers : multiscale molecular modeling [texte imprimé] / Marek Maly, Auteur ; Paola Posocco, Auteur ; Sabrina Pricl, Auteur ; Fermeglia, Maurizio, Auteur . - 2008 . - p. 5023–5038. Bibliogr. p. 5038 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5023–5038 Mots-clés : Copolymers Nanoparticles Hybrid materialsDissipative particle dynamics Résumé : Mixing microphase-separating diblock copolymers and nanoparticles can lead to the self-assembly of organic/inorganic hybrid materials that are spatially organized on the nanometer scale. Controlling particle location and patterns within the polymeric matrix domains remains, however, an unmet need. Computer simulation of such systems constitutes an interesting challenge since an appropriate technique would require the capturing of both the formation of the diblock mesophases and the copolymer−particle and particle−particle interactions, which can affect the ultimate structure of the material. In this paper we discuss the application of dissipative particle dynamics (DPD) to the study of the distribution of nanoparticles in lamellar and hexagonal diblock copolymer matrices. The DPD parameters of the systems were calculated according to a multiscale modeling approach, i.e., from lower scale (atomistic) simulations. The results show that the positioning and ordering of the nanoparticles depend on several different factors, including their covering type and volume fraction. Also, the geometric features of the matrix are found to exert an influence on the particle location and pattern. The overall results provide molecular-level information for the rational, a priori design of new polymer−particle nanocomposites with ad hoc, tailored properties. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071311m

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Density and viscosity as real-time probes for progress of high-pressure polymerizations / Kun Liu in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5039–5047 Titre : Density and viscosity as real-time probes for progress of high-pressure polymerizations : polymerization of Methyl Methacrylate in Acetone Type de document : texte imprimé Auteurs : Kun Liu, Auteur ; Erdogan Kiran, Auteur Année de publication : 2008 Article en page(s) : p. 5039–5047 Note générale : Bibliogr. p. 5047 Langues : Anglais (eng) Mots-clés : Acetone -- methyl methacrylate PolymerizationModel mixtures densityModel viscosity Résumé : Density and viscosity have been used as real-time probes to follow the progress of free-radical polymerization of methyl methacrylate in acetone at high pressures. Specifically, the polymerizations were conducted at 343 K and at 7, 14, 21, 28, 35, and 42 MPa in acetone with AIBN as initiator. Polymers with narrow molecular-weight distributions (Mw/Mn = 1.45–1.55) and without high-molecular-weight tail-ends (Mz/Mw = 1.26–1.33) were formed. The results show that the polymerization proceeds in two distinguishable regimes characterized by different rates of change in density or viscosity. The densities and viscosities of model mixtures of poly(methyl methacrylate) plus methyl methacrylate (the monomer) of known compositions were also measured and used to relate the change in viscosity during polymerization to change in the monomer concentration. The change in monomer concentration was then used in evaluating the rate constant and its pressure dependence. The overall apparent first-order rate constants were found to be in the range 0.002−0.004 min−1 at 7 MPa and 0.006−0.008 min−1 at 42 MPa. The reductions in the time rate of change in density and viscosity are discussed in terms of the polymer concentration and viscosity, reaching levels that can be associated with the chain-overlap concentrations; this leads to the onset of diffusional limitations for macroradicals in solution polymerizations even when the viscosities remain low, around 1 mPa s. The low polydispersities and the absence of high-molecular-weight tailing were interpreted in terms of termination by combination involving “short”−“long” coupling of macroradicals. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716621 [article] Density and viscosity as real-time probes for progress of high-pressure polymerizations : polymerization of Methyl Methacrylate in Acetone [texte imprimé] / Kun Liu, Auteur ; Erdogan Kiran, Auteur . - 2008 . - p. 5039–5047. Bibliogr. p. 5047 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5039–5047 Mots-clés : Acetone -- methyl methacrylate PolymerizationModel mixtures densityModel viscosity Résumé : Density and viscosity have been used as real-time probes to follow the progress of free-radical polymerization of methyl methacrylate in acetone at high pressures. Specifically, the polymerizations were conducted at 343 K and at 7, 14, 21, 28, 35, and 42 MPa in acetone with AIBN as initiator. Polymers with narrow molecular-weight distributions (Mw/Mn = 1.45–1.55) and without high-molecular-weight tail-ends (Mz/Mw = 1.26–1.33) were formed. The results show that the polymerization proceeds in two distinguishable regimes characterized by different rates of change in density or viscosity. The densities and viscosities of model mixtures of poly(methyl methacrylate) plus methyl methacrylate (the monomer) of known compositions were also measured and used to relate the change in viscosity during polymerization to change in the monomer concentration. The change in monomer concentration was then used in evaluating the rate constant and its pressure dependence. The overall apparent first-order rate constants were found to be in the range 0.002−0.004 min−1 at 7 MPa and 0.006−0.008 min−1 at 42 MPa. The reductions in the time rate of change in density and viscosity are discussed in terms of the polymer concentration and viscosity, reaching levels that can be associated with the chain-overlap concentrations; this leads to the onset of diffusional limitations for macroradicals in solution polymerizations even when the viscosities remain low, around 1 mPa s. The low polydispersities and the absence of high-molecular-weight tailing were interpreted in terms of termination by combination involving “short”−“long” coupling of macroradicals. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716621

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Application of group additivity approach to polar and polyfunctional aqueous solutes / Josef Sedlbauer in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5048–5062 Titre : Application of group additivity approach to polar and polyfunctional aqueous solutes Type de document : texte imprimé Auteurs : Josef Sedlbauer, Auteur ; Pavel Jakubu, Auteur Année de publication : 2008 Article en page(s) : p. 5048–5062 Note générale : Bibliogr. p. 5059-5062 Langues : Anglais (eng) Mots-clés : Organic compounds Polar aqueous solutes Polyfunctional Résumé : Estimates of physical or thermodynamic properties of organic compounds are often based on a group contribution approach or other quantitative structure−property relationship. Polar functional groups introduce a perturbation to intramolecular distribution of electrons, resulting in violation of a group additivity assumption known as structural or proximity effects. We propose a method for quantitative evaluation of these effects from experimental data and present the results for polar functional group contributions and their structural/proximity effects calculated for several standard thermodynamic properties of hydration at ambient conditions and at high temperatures and pressures. Recommendations are provided for further developments of group contribution methods in aqueous solutions of organics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071249t [article] Application of group additivity approach to polar and polyfunctional aqueous solutes [texte imprimé] / Josef Sedlbauer, Auteur ; Pavel Jakubu, Auteur . - 2008 . - p. 5048–5062. Bibliogr. p. 5059-5062 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5048–5062 Mots-clés : Organic compounds Polar aqueous solutes Polyfunctional Résumé : Estimates of physical or thermodynamic properties of organic compounds are often based on a group contribution approach or other quantitative structure−property relationship. Polar functional groups introduce a perturbation to intramolecular distribution of electrons, resulting in violation of a group additivity assumption known as structural or proximity effects. We propose a method for quantitative evaluation of these effects from experimental data and present the results for polar functional group contributions and their structural/proximity effects calculated for several standard thermodynamic properties of hydration at ambient conditions and at high temperatures and pressures. Recommendations are provided for further developments of group contribution methods in aqueous solutions of organics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071249t

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Cubic mixing rules / Marcelo S. Zabaloy in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5063–5079 Titre : Cubic mixing rules Type de document : texte imprimé Auteurs : Marcelo S. Zabaloy, Auteur Année de publication : 2008 Article en page(s) : p. 5063–5079 Note générale : Bibliogr. p. 5079 Langues : Anglais (eng) Mots-clés : Asymmetric multicomponent fluid systems Equation-of-state Cubic mixing rules Résumé : The accurate description of thermodynamic properties of asymmetric multicomponent fluid systems of industrial interest, over a wide range of conditions, requires the availability of models that are both consistent and mathematically flexible. Specially suited models are those of the equation-of-state (EOS) type, which are built to represent the properties of liquids, vapors, and supercritical fluids. The composition dependence of EOSs is typically pairwise additive, with binary interaction parameters conventionally fit to match experimental information on binary systems. This is the case for the well-known van der Waals quadratic mixing rules (QMRs), which assume multicomponent system describability from binary parameters. In contrast, cubic mixing rules (CMRs) depend on binary and ternary interaction parameters. Thus, CMRs offer the possibility of increasing the model flexibility, i.e., CMRs are ternionwise additive. This means that, through ternary parameters, CMRs make it possible to influence the model behavior for ternary systems while leaving invariant the description of the corresponding binary subsystems. However, the increased flexibility implies the need for experimental information on ternary systems. This is so, unless we have a method to predict values for ternary parameters from values of binary parameters for the ternary subsystems not having ternary experimental information available, when we want to model the behavior of multicomponent fluids. Mathias, Klotz, and Prausnitz (MKP) [Fluid Phase Equilib. 1991, 67, 31−44] put forward this problem. In this work, we provide a possible solution, i.e., an equation to predict three index ternary parameters from three index binary parameters within the context of CMRs. Our equation matches the Michelsen−Kistenmacher invariance constraint and, in a way, has the pair-based MKP mixing rule in its genesis. The present approach can be extended also to models that are not of the EOS type. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071570b [article] Cubic mixing rules [texte imprimé] / Marcelo S. Zabaloy, Auteur . - 2008 . - p. 5063–5079. Bibliogr. p. 5079 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5063–5079 Mots-clés : Asymmetric multicomponent fluid systems Equation-of-state Cubic mixing rules Résumé : The accurate description of thermodynamic properties of asymmetric multicomponent fluid systems of industrial interest, over a wide range of conditions, requires the availability of models that are both consistent and mathematically flexible. Specially suited models are those of the equation-of-state (EOS) type, which are built to represent the properties of liquids, vapors, and supercritical fluids. The composition dependence of EOSs is typically pairwise additive, with binary interaction parameters conventionally fit to match experimental information on binary systems. This is the case for the well-known van der Waals quadratic mixing rules (QMRs), which assume multicomponent system describability from binary parameters. In contrast, cubic mixing rules (CMRs) depend on binary and ternary interaction parameters. Thus, CMRs offer the possibility of increasing the model flexibility, i.e., CMRs are ternionwise additive. This means that, through ternary parameters, CMRs make it possible to influence the model behavior for ternary systems while leaving invariant the description of the corresponding binary subsystems. However, the increased flexibility implies the need for experimental information on ternary systems. This is so, unless we have a method to predict values for ternary parameters from values of binary parameters for the ternary subsystems not having ternary experimental information available, when we want to model the behavior of multicomponent fluids. Mathias, Klotz, and Prausnitz (MKP) [Fluid Phase Equilib. 1991, 67, 31−44] put forward this problem. In this work, we provide a possible solution, i.e., an equation to predict three index ternary parameters from three index binary parameters within the context of CMRs. Our equation matches the Michelsen−Kistenmacher invariance constraint and, in a way, has the pair-based MKP mixing rule in its genesis. The present approach can be extended also to models that are not of the EOS type. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071570b

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Selective extraction of copper, mercury, silver, and palladium ions from water using hydrophobic ionic liquids / Nicolas Papaiconomou in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5080–5086 Titre : Selective extraction of copper, mercury, silver, and palladium ions from water using hydrophobic ionic liquids Type de document : texte imprimé Auteurs : Nicolas Papaiconomou, Auteur ; Jong-Min Lee, Auteur ; Justin Salminen, Auteur Année de publication : 2008 Article en page(s) : p. 5080–5086 Note générale : Bibliogr. p. 5085-5086 Langues : Anglais (eng) Mots-clés : Dilute metal ions Ionic liquids Résumé : Extraction of dilute metal ions from water was performed near room temperature with a variety of ionic liquids. Distribution coefficients are reported for fourteen metal ions extracted with ionic liquids containing cations 1-octyl-4-methylpyridinium[4MOPYR]+, 1-methyl-1-octylpyrrolidinium[MOPYRRO]+, or 1-methyl-1-octylpiperidinium[MOPIP]+ and anions tetrafluoroborate[BF4]+, trifluoromethyl sulfonate[TfO]+, or nonafluorobutyl sulfonate[NfO]+. Ionic liquids containing octylpyridinium cations are good for extracting mercury ions. However, other metal ions were not significantly extracted by any of these ionic liquids. Extractions were also performed with four new task-specific ionic liquids. When these liquids contain a disulfide functional group, they are efficient and selective for mercury and copper, whereas those containing a nitrile functional group are efficient and selective for silver and palladium. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0706562 [article] Selective extraction of copper, mercury, silver, and palladium ions from water using hydrophobic ionic liquids [texte imprimé] / Nicolas Papaiconomou, Auteur ; Jong-Min Lee, Auteur ; Justin Salminen, Auteur . - 2008 . - p. 5080–5086. Bibliogr. p. 5085-5086 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5080–5086 Mots-clés : Dilute metal ions Ionic liquids Résumé : Extraction of dilute metal ions from water was performed near room temperature with a variety of ionic liquids. Distribution coefficients are reported for fourteen metal ions extracted with ionic liquids containing cations 1-octyl-4-methylpyridinium[4MOPYR]+, 1-methyl-1-octylpyrrolidinium[MOPYRRO]+, or 1-methyl-1-octylpiperidinium[MOPIP]+ and anions tetrafluoroborate[BF4]+, trifluoromethyl sulfonate[TfO]+, or nonafluorobutyl sulfonate[NfO]+. Ionic liquids containing octylpyridinium cations are good for extracting mercury ions. However, other metal ions were not significantly extracted by any of these ionic liquids. Extractions were also performed with four new task-specific ionic liquids. When these liquids contain a disulfide functional group, they are efficient and selective for mercury and copper, whereas those containing a nitrile functional group are efficient and selective for silver and palladium. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0706562

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Growth constants in solidification / Saurabh Agrawal in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5087-5091 Titre : Growth constants in solidification Type de document : texte imprimé Auteurs : Saurabh Agrawal, Auteur ; Lewis E. Johns, Auteur ; Ranga Narayanan, Auteur Année de publication : 2008 Article en page(s) : p. 5087-5091 Note générale : Bibliogr. p. 5091 Langues : Anglais (eng) Mots-clés : Solidification  Growth rates  Bulk phase Résumé : In phase-change problems, there are domain and surface contributions to the dynamics of a moving front. It is ordinarily assumed that the surface contributions are in complete control. This is likely to be true in the case of planar fronts, but it may or may not be true in the cylindrical case. We study the growth rates of disturbances imposed on the surface of a cylindrical solid in equilibrium with its melt and deduce the conditions under which time derivatives of bulk-phase variables are important. They are important in the case of a whisker and are even more important if a solute is added. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070838w [article] Growth constants in solidification [texte imprimé] / Saurabh Agrawal, Auteur ; Lewis E. Johns, Auteur ; Ranga Narayanan, Auteur . - 2008 . - p. 5087-5091. Bibliogr. p. 5091 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5087-5091 Mots-clés : Solidification  Growth rates  Bulk phase Résumé : In phase-change problems, there are domain and surface contributions to the dynamics of a moving front. It is ordinarily assumed that the surface contributions are in complete control. This is likely to be true in the case of planar fronts, but it may or may not be true in the cylindrical case. We study the growth rates of disturbances imposed on the surface of a cylindrical solid in equilibrium with its melt and deduce the conditions under which time derivatives of bulk-phase variables are important. They are important in the case of a whisker and are even more important if a solute is added. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070838w

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A predictive group-contribution simplified PC-SAFT equation of state / Amra Tihic in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5092–5101 Titre : A predictive group-contribution simplified PC-SAFT equation of state : application to polymer systems Type de document : texte imprimé Auteurs : Amra Tihic, Auteur ; Georgios M. Kontogeorgis, Auteur ; Nicolas von Solms, Auteur ; Michael L. Michelsen, Auteur Année de publication : 2008 Article en page(s) : p. 5092–5101 Note générale : Bibliogr. 5100-5101 Langues : Anglais (eng) Mots-clés : Group-contribution method  Equation of state  Polymer parameters Résumé : A group-contribution (GC) method is coupled with the molecular-based perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) to predict its characteristic pure compound parameters. The estimation of group contributions for the parameters is based on a parameter database of 400 low-molecular-weight compounds estimated by fitting experimental vapor pressures and liquid densities. The method has been successfully used for estimating the PC-SAFT parameters for common polymers. Specifically, using the new polymer parameters as calculated from the proposed GC scheme, the simplified PC-SAFT yields rather good predictions of polymer densities and gives promising modeling results of various binary polymer mixtures exhibiting both vapor-liquid and liquid-liquid phase equilibria. In summary, the data required for calculating polymer phase equilibria with the proposed method are the molecular structure of the polymer of interest in terms of functional groups and a single binary interaction parameter for accurate mixture calculations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710768 [article] A predictive group-contribution simplified PC-SAFT equation of state : application to polymer systems [texte imprimé] / Amra Tihic, Auteur ; Georgios M. Kontogeorgis, Auteur ; Nicolas von Solms, Auteur ; Michael L. Michelsen, Auteur . - 2008 . - p. 5092–5101. Bibliogr. 5100-5101 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5092–5101 Mots-clés : Group-contribution method  Equation of state  Polymer parameters Résumé : A group-contribution (GC) method is coupled with the molecular-based perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) to predict its characteristic pure compound parameters. The estimation of group contributions for the parameters is based on a parameter database of 400 low-molecular-weight compounds estimated by fitting experimental vapor pressures and liquid densities. The method has been successfully used for estimating the PC-SAFT parameters for common polymers. Specifically, using the new polymer parameters as calculated from the proposed GC scheme, the simplified PC-SAFT yields rather good predictions of polymer densities and gives promising modeling results of various binary polymer mixtures exhibiting both vapor-liquid and liquid-liquid phase equilibria. In summary, the data required for calculating polymer phase equilibria with the proposed method are the molecular structure of the polymer of interest in terms of functional groups and a single binary interaction parameter for accurate mixture calculations. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710768

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An electrolyte equation of state based on a hydrogen-bonding nonrandom lattice fluid model for concentrated electrolyte solutions / Yong Soo Kim in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5102–5111 Titre : An electrolyte equation of state based on a hydrogen-bonding nonrandom lattice fluid model for concentrated electrolyte solutions Type de document : texte imprimé Auteurs : Yong Soo Kim, Auteur ; Chul Soo Lee, Auteur Année de publication : 2008 Article en page(s) : p. 5102–5111 Note générale : Bibliogr. p. 5110-5111 Langues : Anglais (eng) Mots-clés : Equation of state  Lattice fluids  Nonelectrolyte components  Electrolyte equation state Résumé : Equations of state that are based on lattice fluids have been in use for nonelectrolyte components and their mixtures with somewhat different characteristics from hard-sphere chain-based equations of state or cubic equations. In the present study, an electrolyte equation of state was developed, based on a hydrogen-bonding nonrandom lattice fluid theory, by adding the long-range contribution that is due to the mean spherical approximation. Hydrogen bonding of solvent molecules and solvation between solvent molecules and cations were explicitly included by association contribution to extend the applicability to highly concentrated electrolyte solutions. Segment numbers of ions were obtained from the Pauling diameter, using the previously developed relationship between lattice and off-lattice fluids. The remaining electrolyte parameters—namely, interaction energy between electrolyte and solvent, hydrated ionic diameter, and hydration energy between cation and solvent molecule—were fitted to osmotic coefficients and mean activity coefficients at 298.15 K and 1 bar. Good agreements were obtained between the experimental and calculated results over the wide range of compositions, up to a molality of 20, with average absolute deviations (AADs) of 1.0%, 1.1%, and 1.6% for the osmotic coefficients, the mean activity coefficients, and the densities of 94 aqueous electrolyte solutions, respectively. The equation of state was determined to be applicable to sodium chloride solutions in the temperature range of 273−373 K when these properties were calculated using a temperature-dependent binary interaction parameter. Examples were presented for 1:1 electrolytes to show that parameters of monovalent ions, rather than electrolyte parameters, can be used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0711527 [article] An electrolyte equation of state based on a hydrogen-bonding nonrandom lattice fluid model for concentrated electrolyte solutions [texte imprimé] / Yong Soo Kim, Auteur ; Chul Soo Lee, Auteur . - 2008 . - p. 5102–5111. Bibliogr. p. 5110-5111 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5102–5111 Mots-clés : Equation of state  Lattice fluids  Nonelectrolyte components  Electrolyte equation state Résumé : Equations of state that are based on lattice fluids have been in use for nonelectrolyte components and their mixtures with somewhat different characteristics from hard-sphere chain-based equations of state or cubic equations. In the present study, an electrolyte equation of state was developed, based on a hydrogen-bonding nonrandom lattice fluid theory, by adding the long-range contribution that is due to the mean spherical approximation. Hydrogen bonding of solvent molecules and solvation between solvent molecules and cations were explicitly included by association contribution to extend the applicability to highly concentrated electrolyte solutions. Segment numbers of ions were obtained from the Pauling diameter, using the previously developed relationship between lattice and off-lattice fluids. The remaining electrolyte parameters—namely, interaction energy between electrolyte and solvent, hydrated ionic diameter, and hydration energy between cation and solvent molecule—were fitted to osmotic coefficients and mean activity coefficients at 298.15 K and 1 bar. Good agreements were obtained between the experimental and calculated results over the wide range of compositions, up to a molality of 20, with average absolute deviations (AADs) of 1.0%, 1.1%, and 1.6% for the osmotic coefficients, the mean activity coefficients, and the densities of 94 aqueous electrolyte solutions, respectively. The equation of state was determined to be applicable to sodium chloride solutions in the temperature range of 273−373 K when these properties were calculated using a temperature-dependent binary interaction parameter. Examples were presented for 1:1 electrolytes to show that parameters of monovalent ions, rather than electrolyte parameters, can be used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0711527

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Influence of a single salt (NaCl/Na2SO4) on the solubility of ammonia in liquid mixtures of (water + methanol) / Dirk Schäfer in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5112–5118 Titre : Influence of a single salt (NaCl/Na2SO4) on the solubility of ammonia in liquid mixtures of (water + methanol) Type de document : texte imprimé Auteurs : Dirk Schäfer, Auteur ; Mathias Vogt, Auteur ; Álvaro Pérez-Salado Kamps, Auteur ; Maurer, Gerd, Auteur Année de publication : 2008 Article en page(s) : p. 5112–5118 Note générale : Bibliogr. p. 5118 Langues : Anglais (eng) Mots-clés : Single salts  Ammonia -- liquid mixtures  Water  Methanol Résumé : New experimental results are reported for the influence of two single salts (sodium chloride and sodium sulfate) on the solubility of ammonia in liquid mixtures of water and methanol at 353 and 393 K. The mole fractions of methanol in the (gas-free and salt-free) solvent mixture of water and methanol were about 0.25, 0.5, and 0.75 in the experiments with sodium chloride and about 0.05 and 0.25 in the experiments with sodium sulfate. The molality of the salt varied between about 0.25 and 2 (0.15 and 1) mol/kg of the solvent mixture in the systems with sodium chloride (sodium sulfate). The maximum molality of ammonia was about 6.7 mol/kg of (water + methanol) for both temperatures and for both salts. The maximum total pressure above the liquid solutions was about 0.3 MPa (1 MPa) in the system containing sodium chloride at 353 K (393 K) and about 0.2 MPa (0.7 MPa) in the system with sodium sulfate at 353 K (393 K). The experimental results are used to test a thermodynamic framework which allows the influence of both single strong electrolytes on the solubility of ammonia in liquid mixtures of water and methanol to be predicted. The prediction results are in good agreement with the new experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071169p [article] Influence of a single salt (NaCl/Na2SO4) on the solubility of ammonia in liquid mixtures of (water + methanol) [texte imprimé] / Dirk Schäfer, Auteur ; Mathias Vogt, Auteur ; Álvaro Pérez-Salado Kamps, Auteur ; Maurer, Gerd, Auteur . - 2008 . - p. 5112–5118. Bibliogr. p. 5118 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5112–5118 Mots-clés : Single salts  Ammonia -- liquid mixtures  Water  Methanol Résumé : New experimental results are reported for the influence of two single salts (sodium chloride and sodium sulfate) on the solubility of ammonia in liquid mixtures of water and methanol at 353 and 393 K. The mole fractions of methanol in the (gas-free and salt-free) solvent mixture of water and methanol were about 0.25, 0.5, and 0.75 in the experiments with sodium chloride and about 0.05 and 0.25 in the experiments with sodium sulfate. The molality of the salt varied between about 0.25 and 2 (0.15 and 1) mol/kg of the solvent mixture in the systems with sodium chloride (sodium sulfate). The maximum molality of ammonia was about 6.7 mol/kg of (water + methanol) for both temperatures and for both salts. The maximum total pressure above the liquid solutions was about 0.3 MPa (1 MPa) in the system containing sodium chloride at 353 K (393 K) and about 0.2 MPa (0.7 MPa) in the system with sodium sulfate at 353 K (393 K). The experimental results are used to test a thermodynamic framework which allows the influence of both single strong electrolytes on the solubility of ammonia in liquid mixtures of water and methanol to be predicted. The prediction results are in good agreement with the new experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071169p

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Vapor-liquid equilibria in binary systems of phenol or cresols + water, + toluene, and + octane and liquid-liquid equilibria in binary systems of cresols + water / Mandy Klauck in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5119–5126 Titre : Vapor-liquid equilibria in binary systems of phenol or cresols + water, + toluene, and + octane and liquid-liquid equilibria in binary systems of cresols + water Type de document : texte imprimé Auteurs : Mandy Klauck, Auteur ; Andreas Grenner, Auteur ; Klaus Taubert, Auteur ; Antje Martin, Auteur Année de publication : 2008 Article en page(s) : p. 5119–5126 Note générale : Bibliogr. p. 5126 Langues : Anglais (eng) Mots-clés : Binary systems -- vapor-liquid equilibrium  Liquid-liquid equilibria Résumé : Isothermal vapor-liquid equilibrium data were measured at 333.15 and 363.15 K for the systems toluene + phenol, toluene + 2-cresol, toluene + 3-cresol, toluene + 4-cresol, octane + 2-cresol, octane + 3-cresol, water + phenol, and water + 3 cresol. Additionally, heteroazeotropic data of water + 2-cresol and water + 4-cresol were determined. The solubility of water in 2-cresol, 3-cresol, and 4-cresol was measured by photometric turbidity titration. Excess molar volumes for the systems toluene + phenol or cresols and octane + 2 cresol or + 3 cresol are presented together with Redlich-Kister polynomial fits. The VLE data and, if present, LLE data have been regressed according to the models NRTL, UNIQUAC, and Elliott Suresh Donohue equation of state together with data from the literature. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071214t [article] Vapor-liquid equilibria in binary systems of phenol or cresols + water, + toluene, and + octane and liquid-liquid equilibria in binary systems of cresols + water [texte imprimé] / Mandy Klauck, Auteur ; Andreas Grenner, Auteur ; Klaus Taubert, Auteur ; Antje Martin, Auteur . - 2008 . - p. 5119–5126. Bibliogr. p. 5126 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5119–5126 Mots-clés : Binary systems -- vapor-liquid equilibrium  Liquid-liquid equilibria Résumé : Isothermal vapor-liquid equilibrium data were measured at 333.15 and 363.15 K for the systems toluene + phenol, toluene + 2-cresol, toluene + 3-cresol, toluene + 4-cresol, octane + 2-cresol, octane + 3-cresol, water + phenol, and water + 3 cresol. Additionally, heteroazeotropic data of water + 2-cresol and water + 4-cresol were determined. The solubility of water in 2-cresol, 3-cresol, and 4-cresol was measured by photometric turbidity titration. Excess molar volumes for the systems toluene + phenol or cresols and octane + 2 cresol or + 3 cresol are presented together with Redlich-Kister polynomial fits. The VLE data and, if present, LLE data have been regressed according to the models NRTL, UNIQUAC, and Elliott Suresh Donohue equation of state together with data from the literature. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071214t

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Thermodynamics of hydrogen-bonding mixtures. 5. GE, HE, and TSE and zeotropy of water + acrylic acid / James D. Olson in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5127–5131 Titre : Thermodynamics of hydrogen-bonding mixtures. 5. GE, HE, and TSE and zeotropy of water + acrylic acid Type de document : texte imprimé Auteurs : James D. Olson, Auteur ; Richard E. Morrison, Auteur ; Loren C. Wilson, Auteur Année de publication : 2008 Article en page(s) : p. 5127–5131 Note générale : Bibliogr. p. 5131 Langues : Anglais (eng) Mots-clés : Stirred-flask ebulliometer -- vapor-pressure  Zeotrope  Vapor—liquid equilibrium Résumé : A stirred-flask ebulliometer was used to measure total vapor-pressure (PTx) data on nine mixtures of water + acrylic acid (and the pure components) between 45 and 112 °C and pressures from 10.00 to 101.325 kPa. These PTx data and the derived vapor—liquid equilibrium data show no azeotropic behavior. To verify that water + acrylic acid is a zeotrope at 101.325 kPa, dilute-solution ΔT data at 101.325 kPa were measured in a twin-arm Cottrell-lift-pump ebulliometer. Data on water + propanoic acid, with a known azeotrope at 101.325 kPa, were measured to test the experimental method. These dilute-solution measurements confirmed the known azeotrope for water + propanoic acid and conclusively demonstrated zeotropy for water + acrylic acid at 101.325 kPa. The system exhibits large positive deviations from ideality (derived γ∞ = 2.5−5.7) that decrease with increasing temperature. Equimolar GE/T derived from fitted isothermal activity coefficient parameters decreases with increasing temperature, which predicts a positive HE. The excess function data show that the system water + acrylic acid belongs to the class of mixtures where GE > 0 and HE > 0 (this includes other water + organic acid mixtures); TSE shows a crossover from TSE > 0 to TSE En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0712277 [article] Thermodynamics of hydrogen-bonding mixtures. 5. GE, HE, and TSE and zeotropy of water + acrylic acid [texte imprimé] / James D. Olson, Auteur ; Richard E. Morrison, Auteur ; Loren C. Wilson, Auteur . - 2008 . - p. 5127–5131. Bibliogr. p. 5131 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5127–5131 Mots-clés : Stirred-flask ebulliometer -- vapor-pressure  Zeotrope  Vapor—liquid equilibrium Résumé : A stirred-flask ebulliometer was used to measure total vapor-pressure (PTx) data on nine mixtures of water + acrylic acid (and the pure components) between 45 and 112 °C and pressures from 10.00 to 101.325 kPa. These PTx data and the derived vapor—liquid equilibrium data show no azeotropic behavior. To verify that water + acrylic acid is a zeotrope at 101.325 kPa, dilute-solution ΔT data at 101.325 kPa were measured in a twin-arm Cottrell-lift-pump ebulliometer. Data on water + propanoic acid, with a known azeotrope at 101.325 kPa, were measured to test the experimental method. These dilute-solution measurements confirmed the known azeotrope for water + propanoic acid and conclusively demonstrated zeotropy for water + acrylic acid at 101.325 kPa. The system exhibits large positive deviations from ideality (derived γ∞ = 2.5−5.7) that decrease with increasing temperature. Equimolar GE/T derived from fitted isothermal activity coefficient parameters decreases with increasing temperature, which predicts a positive HE. The excess function data show that the system water + acrylic acid belongs to the class of mixtures where GE > 0 and HE > 0 (this includes other water + organic acid mixtures); TSE shows a crossover from TSE > 0 to TSE En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0712277

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Interaction of reactions and transport / Stuart W. Churchill in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5132–5145 Titre : Interaction of reactions and transport : homogeneous reactions in a round tube. IV. the first-order effects of flow and heat of reaction Type de document : texte imprimé Auteurs : Stuart W. Churchill, Auteur ; Yu, Bo, Auteur ; Yasuo Kawaguchi, Auteur Année de publication : 2008 Article en page(s) : p. 5132–5145 Note générale : Bibliogr. p. 5144-5145 Langues : Anglais (eng) Mots-clés : Round tube  Laminar flow Résumé : The conversion due to first- and second-order, irreversible, equimolar reactions in fully developed isothermal laminar flow in a round tube was computed exactly for perfect, finite, and negligible molecular diffusion of species and energy. The analogous computations for fully developed turbulent flow were based on an essentially exact velocity distribution but an empirical model for the eddy diffusion of species and energy. The effect of a moderate heat of reaction was computed numerically for constant density, constant viscosity, and adiabatic conditions. The identification and implementation of a new dimensionless variable led to the discovery of several near-invariances and, thereby, to very simple but reasonably accurate algebraic representations for the mixed-mean conversion and the mixed-mean temperature for moderately energetic reactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071229r [article] Interaction of reactions and transport : homogeneous reactions in a round tube. IV. the first-order effects of flow and heat of reaction [texte imprimé] / Stuart W. Churchill, Auteur ; Yu, Bo, Auteur ; Yasuo Kawaguchi, Auteur . - 2008 . - p. 5132–5145. Bibliogr. p. 5144-5145 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5132–5145 Mots-clés : Round tube  Laminar flow Résumé : The conversion due to first- and second-order, irreversible, equimolar reactions in fully developed isothermal laminar flow in a round tube was computed exactly for perfect, finite, and negligible molecular diffusion of species and energy. The analogous computations for fully developed turbulent flow were based on an essentially exact velocity distribution but an empirical model for the eddy diffusion of species and energy. The effect of a moderate heat of reaction was computed numerically for constant density, constant viscosity, and adiabatic conditions. The identification and implementation of a new dimensionless variable led to the discovery of several near-invariances and, thereby, to very simple but reasonably accurate algebraic representations for the mixed-mean conversion and the mixed-mean temperature for moderately energetic reactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071229r

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High-pressure phase behavior of the binary systems (propane + diamantane) and (ethane + diamantane) / Wim Poot in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5146–5151 Titre : High-pressure phase behavior of the binary systems (propane + diamantane) and (ethane + diamantane) Type de document : texte imprimé Auteurs : Wim Poot, Auteur ; Theo W. de Loos, Auteur Année de publication : 2008 Article en page(s) : p. 5146–5151 Note générale : Bibliogr. p. 5151 Langues : Anglais (eng) Mots-clés : Vapor-liquid equilibria  Solid-fluid Propane + diamantane system  Ethane system Résumé : (Solid + fluid) and (vapor + liquid) equilibria for the binary systems (propane + diamantane) and (ethane + diamantane) were determined according to the synthetic method in the temperature range 360−510 K and in the pressure ranges 0.3−14 and 0.3−200 MPa, respectively. Also, for both systems the high-temperature branch of the three-phase curve (solid diamantane + liquid + vapor) was determined. In both systems, this curve starts at the second critical endpoint where the three-phase curve intersects the vapor—liquid critical curve and runs to higher temperature with a negative slope dP/dT to the triple point of diamantane. Due to a solid—solid transition of pure diamantane, the three-phase curve (solid diamantane + liquid + vapor) of both systems shows an abrupt change in slope at the point where it intersects the solid—solid transition curve of diamantane. This quadruple point SISIILV is found for (propane + diamantane) at T = 442.64 K and P = 4.110 MPa and for (ethane + diamantane) at T = 445.49 K and P = 9.35 MPa. Some vapor—liquid critical points at low mole fractions of diamantane are reported as well. The coordinates of the second critical endpoint of the (solid diamantane + liquid + vapor) curve are T = 416.28 K and P = 22.81 MPa for (ethane + diamantane) and T = 402.46 K and P = 6.265 MPa for (propane + diamantane). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0712481 [article] High-pressure phase behavior of the binary systems (propane + diamantane) and (ethane + diamantane) [texte imprimé] / Wim Poot, Auteur ; Theo W. de Loos, Auteur . - 2008 . - p. 5146–5151. Bibliogr. p. 5151 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5146–5151 Mots-clés : Vapor-liquid equilibria  Solid-fluid Propane + diamantane system  Ethane system Résumé : (Solid + fluid) and (vapor + liquid) equilibria for the binary systems (propane + diamantane) and (ethane + diamantane) were determined according to the synthetic method in the temperature range 360−510 K and in the pressure ranges 0.3−14 and 0.3−200 MPa, respectively. Also, for both systems the high-temperature branch of the three-phase curve (solid diamantane + liquid + vapor) was determined. In both systems, this curve starts at the second critical endpoint where the three-phase curve intersects the vapor—liquid critical curve and runs to higher temperature with a negative slope dP/dT to the triple point of diamantane. Due to a solid—solid transition of pure diamantane, the three-phase curve (solid diamantane + liquid + vapor) of both systems shows an abrupt change in slope at the point where it intersects the solid—solid transition curve of diamantane. This quadruple point SISIILV is found for (propane + diamantane) at T = 442.64 K and P = 4.110 MPa and for (ethane + diamantane) at T = 445.49 K and P = 9.35 MPa. Some vapor—liquid critical points at low mole fractions of diamantane are reported as well. The coordinates of the second critical endpoint of the (solid diamantane + liquid + vapor) curve are T = 416.28 K and P = 22.81 MPa for (ethane + diamantane) and T = 402.46 K and P = 6.265 MPa for (propane + diamantane). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0712481

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Computer-aided molecular design to select foaming agents using a neural network method / Hiroshi Yamamoto in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5152–5156 Titre : Computer-aided molecular design to select foaming agents using a neural network method Type de document : texte imprimé Auteurs : Hiroshi Yamamoto, Auteur ; Katsumi Tochigi, Auteur Année de publication : 2008 Article en page(s) : p. 5152–5156 Note générale : Bibliogr. p. 5155-5156 Langues : Anglais (eng) Mots-clés : Hydrofluoroether foaming agents  Neural network method Résumé : The development of new foaming agents without chlorine atoms has been vigorously pursued. Hydrofluoroether foaming agents have been proposed as alternatives to chlorofluorocarbons and hydrochlorofluorocarbons by the Research Institute of Innovative Technology for the Earth. Important physicochemical properties for selecting foaming agents include normal boiling points, enthalpies of vaporization, surface tensions, and thermal conductivities. This paper reports predictions of the enthalpy of vaporization using a three-layer neural network with an error back-propagation learning algorithm. Using the proposed method combined with a previously proposed predictive neural network method for boiling points and surface tensions, the molecular design of foaming agents was carried out for trichlorofluoromethane alternatives. Finally, some hydrofluoroethers were selected using thermal conductivity calculated by a multiple regression. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071261l [article] Computer-aided molecular design to select foaming agents using a neural network method [texte imprimé] / Hiroshi Yamamoto, Auteur ; Katsumi Tochigi, Auteur . - 2008 . - p. 5152–5156. Bibliogr. p. 5155-5156 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5152–5156 Mots-clés : Hydrofluoroether foaming agents  Neural network method Résumé : The development of new foaming agents without chlorine atoms has been vigorously pursued. Hydrofluoroether foaming agents have been proposed as alternatives to chlorofluorocarbons and hydrochlorofluorocarbons by the Research Institute of Innovative Technology for the Earth. Important physicochemical properties for selecting foaming agents include normal boiling points, enthalpies of vaporization, surface tensions, and thermal conductivities. This paper reports predictions of the enthalpy of vaporization using a three-layer neural network with an error back-propagation learning algorithm. Using the proposed method combined with a previously proposed predictive neural network method for boiling points and surface tensions, the molecular design of foaming agents was carried out for trichlorofluoromethane alternatives. Finally, some hydrofluoroethers were selected using thermal conductivity calculated by a multiple regression. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071261l

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Phase equilibria in ternary mixtures of methyl oleate, glycerol, and methanol / Alfonsina E. Andreatta in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5157–5164 Titre : Phase equilibria in ternary mixtures of methyl oleate, glycerol, and methanol Type de document : texte imprimé Auteurs : Alfonsina E. Andreatta, Auteur ; Lidia M. Casás, Auteur ; Pablo Hegel, Auteur ; Susana B. Bottini, Auteur Année de publication : 2008 Article en page(s) : p. 5157–5164 Note générale : Bibliogr. p. 5163-5164 Langues : Anglais (eng) Mots-clés : Liquid-liquid equilibrium  Vapor-liquid-liquid Ternary system Résumé : Transesterification reactions are common in the production of some important chemicals, such as biodiesel and mono- and diglycerides. Knowledge of the phase equilibrium conditions of the reactive mixture is essential to explore possible operating conditions for the reactor and the downstream separation process. In this work, liquid—liquid and vapor—liquid—liquid equilibrium data have been measured for the ternary system methyl oleate—methanol—glycerol, at temperatures between 313 and 393 K. The group contribution with association equation of state (GCA-EOS) and the A-UNIFAC model were applied to represent the phase equilibria of this ternary system. Self-association in glycerol and methanol and cross-association with methyl esters were taken into account. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0712885 [article] Phase equilibria in ternary mixtures of methyl oleate, glycerol, and methanol [texte imprimé] / Alfonsina E. Andreatta, Auteur ; Lidia M. Casás, Auteur ; Pablo Hegel, Auteur ; Susana B. Bottini, Auteur . - 2008 . - p. 5157–5164. Bibliogr. p. 5163-5164 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5157–5164 Mots-clés : Liquid-liquid equilibrium  Vapor-liquid-liquid Ternary system Résumé : Transesterification reactions are common in the production of some important chemicals, such as biodiesel and mono- and diglycerides. Knowledge of the phase equilibrium conditions of the reactive mixture is essential to explore possible operating conditions for the reactor and the downstream separation process. In this work, liquid—liquid and vapor—liquid—liquid equilibrium data have been measured for the ternary system methyl oleate—methanol—glycerol, at temperatures between 313 and 393 K. The group contribution with association equation of state (GCA-EOS) and the A-UNIFAC model were applied to represent the phase equilibria of this ternary system. Self-association in glycerol and methanol and cross-association with methyl esters were taken into account. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0712885

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Gibbs free energy of transfer of a methylene group in buffer + ionic liquid biphasic systems / Oscar Rodriguez in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5165–5168 Titre : Gibbs free energy of transfer of a methylene group in buffer + ionic liquid biphasic systems Type de document : texte imprimé Auteurs : Oscar Rodriguez, Auteur ; Pedro P. Madeira, Auteur ; Eugénia A. Macedo, Auteur Année de publication : 2008 Article en page(s) : p. 5165–5168 Note générale : Bibliogr. p. 5168 Langues : Anglais (eng) Mots-clés : Dinitrophenylated amino-acids  Ionic liquid system Résumé : Partitioning experiments for a series of dinitrophenylated (DNP) amino-acids have been conducted in three (ionic liquid + sodium phosphate buffer) biphasic systems at 23 °C. The ionic liquids used were 1-hexyl-3-methylimidazolium tetrafluoroborate ([C6mim][BF4]), 1-octyl-3-methylimidazolium tetrafluoroborate ([C8mim][BF4]), and 1-decyl-3-methylimidazolium tetrafluoroborate ([C10mim][BF4]). The pH of the initial aqueous solution has been fixed at 7.4, using a sodium phosphate buffer. DNP−amino acids distribute preferentially to the ionic liquid phase, and this partition increases with the length of the alkyl chain of the amino acid. The Gibbs free energy of transfer for a methylene group is calculated from the partition coefficients of the solutes. This provides a measurement for the relative hydrophobicity of the conjugated phases, and the obtained values are compared to those of other biphasic systems used in biotechnology (e.g., polymer−polymer and polymer−salt aqueous two-phase systems). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714293 [article] Gibbs free energy of transfer of a methylene group in buffer + ionic liquid biphasic systems [texte imprimé] / Oscar Rodriguez, Auteur ; Pedro P. Madeira, Auteur ; Eugénia A. Macedo, Auteur . - 2008 . - p. 5165–5168. Bibliogr. p. 5168 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5165–5168 Mots-clés : Dinitrophenylated amino-acids  Ionic liquid system Résumé : Partitioning experiments for a series of dinitrophenylated (DNP) amino-acids have been conducted in three (ionic liquid + sodium phosphate buffer) biphasic systems at 23 °C. The ionic liquids used were 1-hexyl-3-methylimidazolium tetrafluoroborate ([C6mim][BF4]), 1-octyl-3-methylimidazolium tetrafluoroborate ([C8mim][BF4]), and 1-decyl-3-methylimidazolium tetrafluoroborate ([C10mim][BF4]). The pH of the initial aqueous solution has been fixed at 7.4, using a sodium phosphate buffer. DNP−amino acids distribute preferentially to the ionic liquid phase, and this partition increases with the length of the alkyl chain of the amino acid. The Gibbs free energy of transfer for a methylene group is calculated from the partition coefficients of the solutes. This provides a measurement for the relative hydrophobicity of the conjugated phases, and the obtained values are compared to those of other biphasic systems used in biotechnology (e.g., polymer−polymer and polymer−salt aqueous two-phase systems). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714293

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Aqueous partial molar volumes from simulation and individual group contributions / Ashish V. Sangwai in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5169–5174 Titre : Aqueous partial molar volumes from simulation and individual group contributions Type de document : texte imprimé Auteurs : Ashish V. Sangwai, Auteur ; Henry S. Ashbaugh, Auteur Année de publication : 2008 Article en page(s) : p. 5169–5174 Note générale : Bibliogr. p. 5174 Langues : Anglais (eng) Mots-clés : Partial molar volumes  Kirkwood−  Buff theory Résumé : Partial molar volumes (PMVs) for a range of organic solutes in aqueous solution are evaluated from molecular simulations using Kirkwood−Buff theory. Long-range oscillatory variations in the Kirkwood−Buff integrals are suppressed using the techniques of Lockwood, Rossky, and Levy [J. Phys. Chem. B, 1999, 103, 1982−1990 and J. Phys. Chem. B, 2000, 104, 4210−4217], enhancing convergence of the calculated partial molar volumes to within the first hydration shell. Contributions from individual constituent groups, such as methylene carbons and alcohol oxygens, are evaluated using proximal correlation functions extended here to heterogeneous molecular species. We find the simulation partial molar volumes are systematically greater than experiment, with the difference between simulation and experiment increasing with solute size. These differences are attributed to possible deficiencies in the volumetric properties of the interaction potentials employed. Nevertheless, we find that the structure of water near identical groups on different solutes is effectively indistinguishable, as quantified by proximal correlation functions. As a result, we propose a new group contribution correlation for the PMV rooted in Kirkwood−Buff theory and the proximity approximation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714448 [article] Aqueous partial molar volumes from simulation and individual group contributions [texte imprimé] / Ashish V. Sangwai, Auteur ; Henry S. Ashbaugh, Auteur . - 2008 . - p. 5169–5174. Bibliogr. p. 5174 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5169–5174 Mots-clés : Partial molar volumes  Kirkwood−  Buff theory Résumé : Partial molar volumes (PMVs) for a range of organic solutes in aqueous solution are evaluated from molecular simulations using Kirkwood−Buff theory. Long-range oscillatory variations in the Kirkwood−Buff integrals are suppressed using the techniques of Lockwood, Rossky, and Levy [J. Phys. Chem. B, 1999, 103, 1982−1990 and J. Phys. Chem. B, 2000, 104, 4210−4217], enhancing convergence of the calculated partial molar volumes to within the first hydration shell. Contributions from individual constituent groups, such as methylene carbons and alcohol oxygens, are evaluated using proximal correlation functions extended here to heterogeneous molecular species. We find the simulation partial molar volumes are systematically greater than experiment, with the difference between simulation and experiment increasing with solute size. These differences are attributed to possible deficiencies in the volumetric properties of the interaction potentials employed. Nevertheless, we find that the structure of water near identical groups on different solutes is effectively indistinguishable, as quantified by proximal correlation functions. As a result, we propose a new group contribution correlation for the PMV rooted in Kirkwood−Buff theory and the proximity approximation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714448

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Catalytic degradation of high-density polyethylene in a reactive extruder / Michael D. Wallis in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5175–5181 Titre : Catalytic degradation of high-density polyethylene in a reactive extruder Type de document : texte imprimé Auteurs : Michael D. Wallis, Auteur ; Sandeep Sarathy, Auteur ; Suresh K. Bhatia, Auteur ; P. Massarotto, Auteur Année de publication : 2008 Article en page(s) : p. 5175–5181 Note générale : Bibliogr. p. 5181 Langues : Anglais (eng) Mots-clés : High-density polyethylene -- degradation  Reactive extruder  Silica−  alumina Résumé : The catalytic degradation of high-density polyethylene was conducted in a reactive extruder at reaction temperatures of 425, 450, and 475 °C using silica−alumina as the cracking catalyst. A continuous kinetic model was proposed and compared to the carbon number distribution of the reaction products. The model prediction of the product selectivity described the experimental data well for a reaction temperature of 425 °C; however, it was too simplistic to predict the decrease in C4 and increase in C3 occurring at higher reaction temperatures. The liquid product obtained from the reactive extruder was comparable to gasoline; however, it did show a significantly higher C5 fraction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714450 [article] Catalytic degradation of high-density polyethylene in a reactive extruder [texte imprimé] / Michael D. Wallis, Auteur ; Sandeep Sarathy, Auteur ; Suresh K. Bhatia, Auteur ; P. Massarotto, Auteur . - 2008 . - p. 5175–5181. Bibliogr. p. 5181 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5175–5181 Mots-clés : High-density polyethylene -- degradation  Reactive extruder  Silica−  alumina Résumé : The catalytic degradation of high-density polyethylene was conducted in a reactive extruder at reaction temperatures of 425, 450, and 475 °C using silica−alumina as the cracking catalyst. A continuous kinetic model was proposed and compared to the carbon number distribution of the reaction products. The model prediction of the product selectivity described the experimental data well for a reaction temperature of 425 °C; however, it was too simplistic to predict the decrease in C4 and increase in C3 occurring at higher reaction temperatures. The liquid product obtained from the reactive extruder was comparable to gasoline; however, it did show a significantly higher C5 fraction. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714450

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Aqueous solubility of some natural phenolic compounds / Fatima L. Mota in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5182–5189 Titre : Aqueous solubility of some natural phenolic compounds Type de document : texte imprimé Auteurs : Fatima L. Mota, Auteur ; António J. Queimada, Auteur ; Simao P. Pinho, Auteur ; Eugénia A. Macedo, Auteur Année de publication : 2008 Article en page(s) : p. 5182–5189 Note générale : Bibliogr. p. 5188-5189 Langues : Anglais (eng) Mots-clés : Hydroxybenzoic acids  Phenylpropenoic Shake-flask method Résumé : In this work, the aqueous solubilities of two hydroxybenzoic acids (gallic and salicylic acid) and three phenylpropenoic acids (trans-cinnamic, ferulic, and caffeic acids) are addressed. Measurements were performed, as a function of temperature, between 288.15 and 323.15 K, using the shake-flask method for generating the saturated aqueous solutions, followed by compositional analysis by spectrophotometric and gravimetric methods. The pH values of the saturated aqueous solutions were measured by potentiometry. Additional thermodynamic properties, which are fundamental for a better understanding of the solubilization process, as well as necessary for the modeling studies, such as melting temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC). Apparent acid dissociation constants (Ka) were obtained by potentiometry titration. The measured data were modeled with the cubic-plus-association (CPA) equation of state (EoS). This EoS is applied, for the first time, for multifunctional associating molecules, and the results indicate that it can adequately be used to represent the measured and other literature data with satisfactory accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071452o [article] Aqueous solubility of some natural phenolic compounds [texte imprimé] / Fatima L. Mota, Auteur ; António J. Queimada, Auteur ; Simao P. Pinho, Auteur ; Eugénia A. Macedo, Auteur . - 2008 . - p. 5182–5189. Bibliogr. p. 5188-5189 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5182–5189 Mots-clés : Hydroxybenzoic acids  Phenylpropenoic Shake-flask method Résumé : In this work, the aqueous solubilities of two hydroxybenzoic acids (gallic and salicylic acid) and three phenylpropenoic acids (trans-cinnamic, ferulic, and caffeic acids) are addressed. Measurements were performed, as a function of temperature, between 288.15 and 323.15 K, using the shake-flask method for generating the saturated aqueous solutions, followed by compositional analysis by spectrophotometric and gravimetric methods. The pH values of the saturated aqueous solutions were measured by potentiometry. Additional thermodynamic properties, which are fundamental for a better understanding of the solubilization process, as well as necessary for the modeling studies, such as melting temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC). Apparent acid dissociation constants (Ka) were obtained by potentiometry titration. The measured data were modeled with the cubic-plus-association (CPA) equation of state (EoS). This EoS is applied, for the first time, for multifunctional associating molecules, and the results indicate that it can adequately be used to represent the measured and other literature data with satisfactory accuracy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071452o

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Computer-aided solvent design for reactions / Milica Folic in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5190–5202 Titre : Computer-aided solvent design for reactions : maximizing product formation Type de document : texte imprimé Auteurs : Milica Folic, Auteur ; Adjiman, Claire S., Auteur ; Efstratios N. Pistikopoulos, Auteur Année de publication : 2008 Article en page(s) : p. 5190–5202 Note générale : Bibliogr. p. 5201-5202 Langues : Anglais (eng) Mots-clés : Computer-aided methodology  Solvents  Complex reaction systems Résumé : A hybrid experimental/computer-aided methodology for the design of solvents for reactions, recently proposed by the authors [Folić et al., AIChE J. 2007, 53, 1240–1256], is extended. The methodology is based on the use of a few reaction rate measurements to build a reaction model, followed by the formulation and solution of an optimal computer-aided molecular design (CAMD) problem. The treatment of complex reaction systems, such as competing or consecutive reactions, is considered through the incorporation of a simple reactor model in the problem formulation. This approach is applied to two model reaction schemes, and it is shown that, in principle, it is possible to identify solvents that maximize product formation by enhancing the main reaction and suppressing byproduct formation. Since very few measurements are used to build the reaction model, the effect of uncertainty is tackled explicitly in a stochastic formulation of the CAMD problem. An approach to sensitivity analysis for the identification of the key model parameters is discussed. Using this information to generate scenarios, a stochastic optimization problem (whose objective is to determine the solvents with the best expected performance) is then solved. The final output consists of a list of candidate solvents that can be targeted for experimentation. The methodology is demonstrated on a Menschutkin reaction, which is a representative SN2 reaction. This shows that the uncertainty in the reaction model has little impact on the types of solvent molecules that have the best performance. Dinitrates are found to be a promising class of solvents, with regard to maximizing the reaction rate constant. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714549 [article] Computer-aided solvent design for reactions : maximizing product formation [texte imprimé] / Milica Folic, Auteur ; Adjiman, Claire S., Auteur ; Efstratios N. Pistikopoulos, Auteur . - 2008 . - p. 5190–5202. Bibliogr. p. 5201-5202 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5190–5202 Mots-clés : Computer-aided methodology  Solvents  Complex reaction systems Résumé : A hybrid experimental/computer-aided methodology for the design of solvents for reactions, recently proposed by the authors [Folić et al., AIChE J. 2007, 53, 1240–1256], is extended. The methodology is based on the use of a few reaction rate measurements to build a reaction model, followed by the formulation and solution of an optimal computer-aided molecular design (CAMD) problem. The treatment of complex reaction systems, such as competing or consecutive reactions, is considered through the incorporation of a simple reactor model in the problem formulation. This approach is applied to two model reaction schemes, and it is shown that, in principle, it is possible to identify solvents that maximize product formation by enhancing the main reaction and suppressing byproduct formation. Since very few measurements are used to build the reaction model, the effect of uncertainty is tackled explicitly in a stochastic formulation of the CAMD problem. An approach to sensitivity analysis for the identification of the key model parameters is discussed. Using this information to generate scenarios, a stochastic optimization problem (whose objective is to determine the solvents with the best expected performance) is then solved. The final output consists of a list of candidate solvents that can be targeted for experimentation. The methodology is demonstrated on a Menschutkin reaction, which is a representative SN2 reaction. This shows that the uncertainty in the reaction model has little impact on the types of solvent molecules that have the best performance. Dinitrates are found to be a promising class of solvents, with regard to maximizing the reaction rate constant. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714549

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Salting-out of lysozyme and ovalbumin from mixtures / Yu-Chia Cheng in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5203–5213 Titre : Salting-out of lysozyme and ovalbumin from mixtures : predicting precipitation performance from protein-protein interactions Type de document : texte imprimé Auteurs : Yu-Chia Cheng, Auteur ; Carolina L. Bianco, Auteur ; Stanley I. Sandler, Auteur ; Abraham M. Lenhoff, Auteur Année de publication : 2008 Article en page(s) : p. 5203–5213 Note générale : Bibliogr. p. 5212-5213 Langues : Anglais (eng) Mots-clés : Protein−  protein interactions -- ovalbumin  lysozyme  Cross-interaction chromatograph Résumé : Protein−protein interactions, whether desirable or not, can have direct effects on protein separations. The most obvious of these are interactions between similar molecules, which determine the thermodynamic properties and phase behavior of protein solutions. Interactions between dissimilar molecules also affect the properties and phase behavior of protein mixtures and, therefore, protein separations. Here, we seek to quantify these effects by comparing precipitation behavior from binary solutions with direct measurements of protein−protein interactions using cross-interaction chromatography, which is a variant of affinity chromatography that provides data that can be interpreted in terms of the virial cross-coefficient. First, the effects of pH, ionic strength, different precipitants and the initial protein concentrations and their ratio on the binary precipitation of lysozyme and ovalbumin were investigated. Next, self- and cross-interaction measurements were used to suggest the optimal precipitation conditions for separating lysozyme from ovalbumin. The results show that protein interactions can explain anomalies and inconsistencies that frequently confound the extraction of meaningful general trends in separations analyses. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071462p [article] Salting-out of lysozyme and ovalbumin from mixtures : predicting precipitation performance from protein-protein interactions [texte imprimé] / Yu-Chia Cheng, Auteur ; Carolina L. Bianco, Auteur ; Stanley I. Sandler, Auteur ; Abraham M. Lenhoff, Auteur . - 2008 . - p. 5203–5213. Bibliogr. p. 5212-5213 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5203–5213 Mots-clés : Protein−  protein interactions -- ovalbumin  lysozyme  Cross-interaction chromatograph Résumé : Protein−protein interactions, whether desirable or not, can have direct effects on protein separations. The most obvious of these are interactions between similar molecules, which determine the thermodynamic properties and phase behavior of protein solutions. Interactions between dissimilar molecules also affect the properties and phase behavior of protein mixtures and, therefore, protein separations. Here, we seek to quantify these effects by comparing precipitation behavior from binary solutions with direct measurements of protein−protein interactions using cross-interaction chromatography, which is a variant of affinity chromatography that provides data that can be interpreted in terms of the virial cross-coefficient. First, the effects of pH, ionic strength, different precipitants and the initial protein concentrations and their ratio on the binary precipitation of lysozyme and ovalbumin were investigated. Next, self- and cross-interaction measurements were used to suggest the optimal precipitation conditions for separating lysozyme from ovalbumin. The results show that protein interactions can explain anomalies and inconsistencies that frequently confound the extraction of meaningful general trends in separations analyses. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071462p

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Solubility and diffusivity of gases in mixed matrix membranes containing hydrophobic fumed silica / Maria Grazia De Angelis in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5214–5226 Titre : Solubility and diffusivity of gases in mixed matrix membranes containing hydrophobic fumed silica : correlations and predictions based on the NELF model Type de document : texte imprimé Auteurs : Maria Grazia De Angelis, Auteur ; Giulio C. Sarti, Auteur Année de publication : 2008 Article en page(s) : p. 5214–5226 Note générale : Bibliogr. p. 5225-5226 Langues : Anglais (eng) Mots-clés : Fumed silica  Gas diffusivity  NELF model Résumé : The addition of fumed silica particles to glassy polymers such as PTMSP and Teflon AF 2400 results in an enhancement of gas diffusivity and permeability that is not captured by traditional models for composites because both volume and gas solubility of the composite material are underestimated by the additive rule based on pure component properties. Such effects have been attributed to the creation of additional free volume due to the insertion of filler in the polymeric matrix. In this work, we use the NELF model to relate gas solubility in the composite material to the variations induced by the addition of filler on polymer density and swellability. From these values, the fractional free volume (FFV) increase produced in the polymeric phase by filler incorporation may be evaluated and, in turn, also the diffusivity in the composite material can be calculated as a function of filler content on the basis of its relation to FFV. The gas diffusivity data for n-C4H10 in AF 2400 and AF 2400-based mixed matrices, as well as those relative to N2, CH4, C2H6, C3H8, and n-C4H10 in PTMSP, follow closely the correlation found, which contains only one adjustable parameter for each penetrant-polymer couple. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714910 [article] Solubility and diffusivity of gases in mixed matrix membranes containing hydrophobic fumed silica : correlations and predictions based on the NELF model [texte imprimé] / Maria Grazia De Angelis, Auteur ; Giulio C. Sarti, Auteur . - 2008 . - p. 5214–5226. Bibliogr. p. 5225-5226 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5214–5226 Mots-clés : Fumed silica  Gas diffusivity  NELF model Résumé : The addition of fumed silica particles to glassy polymers such as PTMSP and Teflon AF 2400 results in an enhancement of gas diffusivity and permeability that is not captured by traditional models for composites because both volume and gas solubility of the composite material are underestimated by the additive rule based on pure component properties. Such effects have been attributed to the creation of additional free volume due to the insertion of filler in the polymeric matrix. In this work, we use the NELF model to relate gas solubility in the composite material to the variations induced by the addition of filler on polymer density and swellability. From these values, the fractional free volume (FFV) increase produced in the polymeric phase by filler incorporation may be evaluated and, in turn, also the diffusivity in the composite material can be calculated as a function of filler content on the basis of its relation to FFV. The gas diffusivity data for n-C4H10 in AF 2400 and AF 2400-based mixed matrices, as well as those relative to N2, CH4, C2H6, C3H8, and n-C4H10 in PTMSP, follow closely the correlation found, which contains only one adjustable parameter for each penetrant-polymer couple. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714910

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Biohydrogen and methane production from cheese whey in a two-stage anaerobic process / Georgia Antonopoulou in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5227–5233 Titre : Biohydrogen and methane production from cheese whey in a two-stage anaerobic process Type de document : texte imprimé Auteurs : Georgia Antonopoulou, Auteur ; Katerina Stamatelatou, Auteur ; Nikolaos Venetsaneas, Auteur ; Michael Kornaros, Auteur Année de publication : 2008 Article en page(s) : p. 5227–5233 Note générale : Bibliogr. p. 5232-5233 Langues : Anglais (eng) Mots-clés : Hydrogen production  Methane Anaerobic process Résumé : The aim of the present study was to investigate the potential of hydrogen and subsequent methane production from raw cheese whey at 35 °C. The fermentative hydrogen production process from raw cheese whey was conducted in a continuous-type stirred tank bioreactor, operated at low hydraulic retention time (HRT; 24 h). In this stage, the carbohydrates contained in cheese whey are fermented to a mixture of acids and a gaseous mixture rich in hydrogen. The continuous fermentative hydrogen production was sustained by the indigenous microflora already contained in the raw cheese whey because the bioreactor was not seeded with any source of inoculum. At a HRT of 24 h, the hydrogen production rate was 7.53 L of H2/day, while the yield of hydrogen produced was 0.041 m3of H2/kg of chemical oxygen demand (COD) added or 2.49 L of H2/L of cheese whey. The mixed liquor from this stage was further digested to biogas in a periodic anaerobic baffled reactor (PABR), a baffled-type bioreactor. The PABR was operated at HRTs of 20, 10, and 4.4 days. The highest biogas and methane production rates were 105.9 L of biogas/day and 75.6 L of CH4/day, respectively, and were obtained at an HRT of 4.4 days. During this stage, COD reduction reached 94%, obtained at an HRT of 4.4 days. Furthermore, the methane potential of the raw cheese whey was assessed by conducting a biochemical methane potential test. It was estimated to be 0.31 m3 of CH4/kg of COD added or 17.9 L of CH4/L of cheese whey. This work demonstrated that biohydrogen production from cheese whey can be very efficiently coupled with methane production in a subsequent step, exploiting the gaseous biofuel potential of this wastewater type. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071622x [article] Biohydrogen and methane production from cheese whey in a two-stage anaerobic process [texte imprimé] / Georgia Antonopoulou, Auteur ; Katerina Stamatelatou, Auteur ; Nikolaos Venetsaneas, Auteur ; Michael Kornaros, Auteur . - 2008 . - p. 5227–5233. Bibliogr. p. 5232-5233 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5227–5233 Mots-clés : Hydrogen production  Methane Anaerobic process Résumé : The aim of the present study was to investigate the potential of hydrogen and subsequent methane production from raw cheese whey at 35 °C. The fermentative hydrogen production process from raw cheese whey was conducted in a continuous-type stirred tank bioreactor, operated at low hydraulic retention time (HRT; 24 h). In this stage, the carbohydrates contained in cheese whey are fermented to a mixture of acids and a gaseous mixture rich in hydrogen. The continuous fermentative hydrogen production was sustained by the indigenous microflora already contained in the raw cheese whey because the bioreactor was not seeded with any source of inoculum. At a HRT of 24 h, the hydrogen production rate was 7.53 L of H2/day, while the yield of hydrogen produced was 0.041 m3of H2/kg of chemical oxygen demand (COD) added or 2.49 L of H2/L of cheese whey. The mixed liquor from this stage was further digested to biogas in a periodic anaerobic baffled reactor (PABR), a baffled-type bioreactor. The PABR was operated at HRTs of 20, 10, and 4.4 days. The highest biogas and methane production rates were 105.9 L of biogas/day and 75.6 L of CH4/day, respectively, and were obtained at an HRT of 4.4 days. During this stage, COD reduction reached 94%, obtained at an HRT of 4.4 days. Furthermore, the methane potential of the raw cheese whey was assessed by conducting a biochemical methane potential test. It was estimated to be 0.31 m3 of CH4/kg of COD added or 17.9 L of CH4/L of cheese whey. This work demonstrated that biohydrogen production from cheese whey can be very efficiently coupled with methane production in a subsequent step, exploiting the gaseous biofuel potential of this wastewater type. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071622x

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Model-based calculation of solid solubility for solvent selection / Hassan Modarresi in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5234–5242 Titre : Model-based calculation of solid solubility for solvent selection : a review Type de document : texte imprimé Auteurs : Hassan Modarresi, Auteur ; Elisa Conte, Auteur ; Jens Abildskov, Auteur Année de publication : 2008 Article en page(s) : p. 5234–5242 Note générale : Bibliogr. p. 5242 Langues : Anglais (eng) Mots-clés : Solvent selection  Solubility  Contribution−  atom connectivity models Résumé : Solvent selection is one of the major concerns in the early development of many chemicals-based products from the pharmaceutical, agrochemicals, food, and specialty chemicals industries. Because of the nature of the active chemicals in the product, the most important solvent property is the solubility of complex solids. Predictive models for estimation of solid solubility in different organic solvents, especially suitable for solvent-selection procedures, are reviewed. Also, schemes that can be employed for solvent selection and/or solubility calculation through limited available experimental data are reviewed. For initial solvent screening and for many solvent-based calculations, the Hansen solubility parameters are useful property values to have. For this purpose, new combined group contribution−atom connectivity models for predictions of the three Hansen solubility parameters with a very wide application range are presented. These models are able to predict the Hansen solubility parameters for organic chemicals with C, H, N, O, F, Cl, Br, I, S, and P atoms. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716363 [article] Model-based calculation of solid solubility for solvent selection : a review [texte imprimé] / Hassan Modarresi, Auteur ; Elisa Conte, Auteur ; Jens Abildskov, Auteur . - 2008 . - p. 5234–5242. Bibliogr. p. 5242 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5234–5242 Mots-clés : Solvent selection  Solubility  Contribution−  atom connectivity models Résumé : Solvent selection is one of the major concerns in the early development of many chemicals-based products from the pharmaceutical, agrochemicals, food, and specialty chemicals industries. Because of the nature of the active chemicals in the product, the most important solvent property is the solubility of complex solids. Predictive models for estimation of solid solubility in different organic solvents, especially suitable for solvent-selection procedures, are reviewed. Also, schemes that can be employed for solvent selection and/or solubility calculation through limited available experimental data are reviewed. For initial solvent screening and for many solvent-based calculations, the Hansen solubility parameters are useful property values to have. For this purpose, new combined group contribution−atom connectivity models for predictions of the three Hansen solubility parameters with a very wide application range are presented. These models are able to predict the Hansen solubility parameters for organic chemicals with C, H, N, O, F, Cl, Br, I, S, and P atoms. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716363

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Fisher information, entropy, and the second and third laws of thermodynamics / Heriberto Cabezas in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5243–5249 Titre : Fisher information, entropy, and the second and third laws of thermodynamics Type de document : texte imprimé Auteurs : Heriberto Cabezas, Auteur ; Arunprakash T. Karunanithi, Auteur Année de publication : 2008 Article en page(s) : p. 5243–5249 Note générale : Bibliogr. p. 5249 Langues : Anglais (eng) Mots-clés : Thermodynamics -- Fisher information  Gas mixtures Résumé : We propose Fisher information as a new calculable thermodynamic property that can be shown to follow the second and third laws of thermodynamics. However, Fisher information is qualitatively different from entropy and potentially possesses much more structure. Hence, a mathematical expression is derived for computing the Fisher information of a system of many molecules from the canonical partition function. This development is further illustrated through the derivation of Fisher information expressions for a pure ideal gas and an ideal gas mixture. Some of the unique properties of Fisher information are then explored through the classic experiment of the isochoric mixing of two ideal gases. Note that, although the entropy of isochorically mixing two ideal gases is always positive and is dependent only on the respective mole fractions of the two gases, the Fisher information of mixing has far more structure, involving the mole numbers, molecular masses, temperature, and volume. Although the application of Fisher information to molecular systems is clearly in its infancy, it is hoped that the present work will catalyze further investigation into a new and truly unique line of thought on thermodynamics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017756 [article] Fisher information, entropy, and the second and third laws of thermodynamics [texte imprimé] / Heriberto Cabezas, Auteur ; Arunprakash T. Karunanithi, Auteur . - 2008 . - p. 5243–5249. Bibliogr. p. 5249 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5243–5249 Mots-clés : Thermodynamics -- Fisher information  Gas mixtures Résumé : We propose Fisher information as a new calculable thermodynamic property that can be shown to follow the second and third laws of thermodynamics. However, Fisher information is qualitatively different from entropy and potentially possesses much more structure. Hence, a mathematical expression is derived for computing the Fisher information of a system of many molecules from the canonical partition function. This development is further illustrated through the derivation of Fisher information expressions for a pure ideal gas and an ideal gas mixture. Some of the unique properties of Fisher information are then explored through the classic experiment of the isochoric mixing of two ideal gases. Note that, although the entropy of isochorically mixing two ideal gases is always positive and is dependent only on the respective mole fractions of the two gases, the Fisher information of mixing has far more structure, involving the mole numbers, molecular masses, temperature, and volume. Although the application of Fisher information to molecular systems is clearly in its infancy, it is hoped that the present work will catalyze further investigation into a new and truly unique line of thought on thermodynamics. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017756

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Membranes, phase interfaces, and separations / Kamalesh K. Sirkar in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5250–5266 Titre : Membranes, phase interfaces, and separations : novel techniques and membranes: an overview Type de document : texte imprimé Auteurs : Kamalesh K. Sirkar, Auteur Année de publication : 2008 Article en page(s) : p. 5250–5266 Note générale : Bibliogr. p. 5264-5266 Langues : Anglais (eng) Mots-clés : Membranes  Bulk phase interface Résumé : Membranes and bulk phase interfaces share a close relation in separations. The bulk phase interface may be a fluid−fluid, fluid−solid, or solid−solid interface; it may be immobilized or mobile. In conventional membrane separations, two-phase interfaces exist on two sides of the membrane, two solid−fluid interfaces for solid membranes. Conventional equilibrium separations, however, have only one bulk phase interface. Such an interface in gas−liquid, vapor−liquid, liquid−liquid, and subcritical/supercritical fluid−liquid separation systems may be created by phase-interface immobilization at a membrane pore mouth as in membrane contactor-based nondispersive equilibrium separations. Membrane emulsification/sparging/degassing leads to dispersion-based creation of mobile phase interfaces and phase contacting. Convective transport through membrane pores provides efficient solid−liquid contacting as in membrane chromatography. Antisolvent crystallization via dispersion/mixing through membrane pores creates new mobile solid−liquid interfaces. Solid−solid phase interfaces developed via a minor phase consisting of inorganic flakes, inactive fillers, active fillers, or a second polymer phase facilitate the development of a variety of polymeric membranes, porous as well as nonporous. By having two fluid−fluid phase interfaces immobilized on two sides of a porous membrane, liquid membranes and gas membranes have been developed successfully. A composite membrane having a nonporous/nanoporous coating can lead to two fluid−solid phase interfaces or three fluid−fluid phase interfaces for novel separations. The presence of two or more contiguous porous/nonporous membranes in one separation device leads to the existence of multiple bulk phase interfaces or membrane−fluid phase interfaces creating novel liquid membrane structures and separation capabilities in addition to internal staging for separation. The critical role played by the interaction of phase interfaces and membranes vis-à-vis many new separation techniques and membranes developed, commercialized, or being developed will be illustrated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001952 [article] Membranes, phase interfaces, and separations : novel techniques and membranes: an overview [texte imprimé] / Kamalesh K. Sirkar, Auteur . - 2008 . - p. 5250–5266. Bibliogr. p. 5264-5266 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5250–5266 Mots-clés : Membranes  Bulk phase interface Résumé : Membranes and bulk phase interfaces share a close relation in separations. The bulk phase interface may be a fluid−fluid, fluid−solid, or solid−solid interface; it may be immobilized or mobile. In conventional membrane separations, two-phase interfaces exist on two sides of the membrane, two solid−fluid interfaces for solid membranes. Conventional equilibrium separations, however, have only one bulk phase interface. Such an interface in gas−liquid, vapor−liquid, liquid−liquid, and subcritical/supercritical fluid−liquid separation systems may be created by phase-interface immobilization at a membrane pore mouth as in membrane contactor-based nondispersive equilibrium separations. Membrane emulsification/sparging/degassing leads to dispersion-based creation of mobile phase interfaces and phase contacting. Convective transport through membrane pores provides efficient solid−liquid contacting as in membrane chromatography. Antisolvent crystallization via dispersion/mixing through membrane pores creates new mobile solid−liquid interfaces. Solid−solid phase interfaces developed via a minor phase consisting of inorganic flakes, inactive fillers, active fillers, or a second polymer phase facilitate the development of a variety of polymeric membranes, porous as well as nonporous. By having two fluid−fluid phase interfaces immobilized on two sides of a porous membrane, liquid membranes and gas membranes have been developed successfully. A composite membrane having a nonporous/nanoporous coating can lead to two fluid−solid phase interfaces or three fluid−fluid phase interfaces for novel separations. The presence of two or more contiguous porous/nonporous membranes in one separation device leads to the existence of multiple bulk phase interfaces or membrane−fluid phase interfaces creating novel liquid membrane structures and separation capabilities in addition to internal staging for separation. The critical role played by the interaction of phase interfaces and membranes vis-à-vis many new separation techniques and membranes developed, commercialized, or being developed will be illustrated. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8001952

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Efficient chromium(VI) adsorption by cassia marginata seed gum functionalized with poly(methylmethacrylate) using microwave irradiation / Vandana Singh in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5267–5276 Titre : Efficient chromium(VI) adsorption by cassia marginata seed gum functionalized with poly(methylmethacrylate) using microwave irradiation Type de document : texte imprimé Auteurs : Vandana Singh, Auteur ; Ajit Kumar Sharma, Auteur ; Premlata Kumari, Auteur Année de publication : 2008 Article en page(s) : p. 5267–5276 Note générale : Bibliogr. p. 5275-5276 Langues : Anglais (eng) Mots-clés : Chromium(VI) treatment methods -- toxic sludge  Cassia marginata seed gum biosorbent derived  Aqueous solution Résumé : Increasing cost of the chemicals and production of toxic sludge in the Cr(VI) treatment methods have attracted attention toward the use of biosorbents for Cr(VI) removal. The present study evaluates a novel biosorbent derived from Cassia marginata seed gum in the removal of Cr(VI) from the aqueous solution and wastewater. The adsorbent was synthesized using microwave irradiation in the absence of any radical initiator or catalyst in good yield. Adsorbents of different performances could be obtained by varying the amount of the methylmethacrylate, microwave power, and exposure time. A representative sample of microwave synthesized adsorbent was characterized using FTIR, XRD, TGA, and SEM analysis. Cr(VI) sorption was optimized using the copolymer sample of highest grafting ratio and efficiency (270% G and 59.65% E) where the removal was found to be pH and concentration dependent, pH 1.0 being the optimum value at which from 20 mL of 100 ppm Cr(VI) solution, 16.94 mg/g Cr(VI), could be removed using 5 g/L adsorbent dose at 30 °C. The adsorption data followed both Langmuir (R2 = 0.9703) and Freundlich isotherms (R2 = 0.8957) probably due to the real heterogeneous nature of the surface sites involved in the metal uptake, and overall sorption of Cr(VI) on the biosorbent is complex and involves more than one mechanisms. The adsorption followed second order kinetics, the rate constant being 0.10 × 10−5 g/(mg min) at 100 mg/L Cr(VI) concentration. The adsorbent was also found efficient in Cr(VI) removal from real industrial wastewater. Used copolymer was recycled after stripping off the adsorbed chromium with 2 M NaOH where after each cycle a successive decrease in the binding capacity was observed. To understand the advantage of using microwaves in the adsorbent synthesis, the copolymer synthesized using a K2S2O8/ascorbic acid redox pair at identical monomer concentrations (220% G and 48.6% E) was also evaluated as Cr(VI) sorbent, and the results obtained were compared with that of microwave synthesized copolymer. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070467j [article] Efficient chromium(VI) adsorption by cassia marginata seed gum functionalized with poly(methylmethacrylate) using microwave irradiation [texte imprimé] / Vandana Singh, Auteur ; Ajit Kumar Sharma, Auteur ; Premlata Kumari, Auteur . - 2008 . - p. 5267–5276. Bibliogr. p. 5275-5276 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5267–5276 Mots-clés : Chromium(VI) treatment methods -- toxic sludge  Cassia marginata seed gum biosorbent derived  Aqueous solution Résumé : Increasing cost of the chemicals and production of toxic sludge in the Cr(VI) treatment methods have attracted attention toward the use of biosorbents for Cr(VI) removal. The present study evaluates a novel biosorbent derived from Cassia marginata seed gum in the removal of Cr(VI) from the aqueous solution and wastewater. The adsorbent was synthesized using microwave irradiation in the absence of any radical initiator or catalyst in good yield. Adsorbents of different performances could be obtained by varying the amount of the methylmethacrylate, microwave power, and exposure time. A representative sample of microwave synthesized adsorbent was characterized using FTIR, XRD, TGA, and SEM analysis. Cr(VI) sorption was optimized using the copolymer sample of highest grafting ratio and efficiency (270% G and 59.65% E) where the removal was found to be pH and concentration dependent, pH 1.0 being the optimum value at which from 20 mL of 100 ppm Cr(VI) solution, 16.94 mg/g Cr(VI), could be removed using 5 g/L adsorbent dose at 30 °C. The adsorption data followed both Langmuir (R2 = 0.9703) and Freundlich isotherms (R2 = 0.8957) probably due to the real heterogeneous nature of the surface sites involved in the metal uptake, and overall sorption of Cr(VI) on the biosorbent is complex and involves more than one mechanisms. The adsorption followed second order kinetics, the rate constant being 0.10 × 10−5 g/(mg min) at 100 mg/L Cr(VI) concentration. The adsorbent was also found efficient in Cr(VI) removal from real industrial wastewater. Used copolymer was recycled after stripping off the adsorbed chromium with 2 M NaOH where after each cycle a successive decrease in the binding capacity was observed. To understand the advantage of using microwaves in the adsorbent synthesis, the copolymer synthesized using a K2S2O8/ascorbic acid redox pair at identical monomer concentrations (220% G and 48.6% E) was also evaluated as Cr(VI) sorbent, and the results obtained were compared with that of microwave synthesized copolymer. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070467j

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Dye destruction and simultaneous generation of sodium hydroxide using a divided electrochemical reactor / S. Raghu in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5277–5283 Titre : Dye destruction and simultaneous generation of sodium hydroxide using a divided electrochemical reactor Type de document : texte imprimé Auteurs : S. Raghu, Auteur ; C. Ahmed Basha, Auteur Année de publication : 2008 Article en page(s) : p. 5277–5283 Note générale : Bibliogr. 5282-5283 Langues : Anglais (eng) Mots-clés : Textile dye  Dye -- Degradation  Electrochemical proces Résumé : Textile dye bath effluent contains high concentrations of organic dye, sodium chloride, and other chemicals which inhibit the activity of microorganisms during biological oxidation. Hence high concentrations of organic dye and total dissolved solids have to be removed considerably before biological treatment. In this paper, degradation of dye effluent and simultaneous generation of caustic soda in an electrochemical membrane cell was investigated. Experiments were carried out at different current densities and different flow rates using Ti/RuO2/IrO2 as anode and stainless steel as cathode. In the present study of dye effluent treatment the results showed that the electrochemical process could effectively remove COD and color by anodic oxidation (92.16% and 100%) and concentrate caustic soda from 40 to 210.28 g L−1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070675b [article] Dye destruction and simultaneous generation of sodium hydroxide using a divided electrochemical reactor [texte imprimé] / S. Raghu, Auteur ; C. Ahmed Basha, Auteur . - 2008 . - p. 5277–5283. Bibliogr. 5282-5283 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5277–5283 Mots-clés : Textile dye  Dye -- Degradation  Electrochemical proces Résumé : Textile dye bath effluent contains high concentrations of organic dye, sodium chloride, and other chemicals which inhibit the activity of microorganisms during biological oxidation. Hence high concentrations of organic dye and total dissolved solids have to be removed considerably before biological treatment. In this paper, degradation of dye effluent and simultaneous generation of caustic soda in an electrochemical membrane cell was investigated. Experiments were carried out at different current densities and different flow rates using Ti/RuO2/IrO2 as anode and stainless steel as cathode. In the present study of dye effluent treatment the results showed that the electrochemical process could effectively remove COD and color by anodic oxidation (92.16% and 100%) and concentrate caustic soda from 40 to 210.28 g L−1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070675b

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Reactions and kinetics of Cl(III) decomposition / Tuula Lehtimaa in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5284–5290 Titre : Reactions and kinetics of Cl(III) decomposition Type de document : texte imprimé Auteurs : Tuula Lehtimaa, Auteur ; Ville Tarvo, Auteur ; Gérard Mortha, Auteur Année de publication : 2008 Article en page(s) : p. 5284–5290 Note générale : Bibliogr. p. 5289-5290 Langues : Anglais (eng) Mots-clés : Chlorite acid  Chlorous Self-decomposition Résumé : Several pathways leading to the decomposition of chlorite and chlorous acid have been published. In this study, both experimental and computational approaches have been applied to clarify the authenticity of the different routes. The decomposition of chlorine (III), i.e. chlorous acid and chlorite, was monitored with iodometric titration at changing chloride concentrations, temperature, and existence of iron (III) at pH 1−3. Dimethylsulfoxide (DMSO) was used to prevent hypochlorous acid from reacting with chlorite. Chlorine dioxide was not formed in the absence of metals when hypochlorous acid and chlorine were trapped. The self-decomposition of Cl(III) proceeds only via the acidic form while chlorite is stable. Chloride ions enhanced the chlorous acid decomposition rate especially at low pH. Chlorite decomposes in the presence of Fe3+ ions. General kinetic parameters and their temperature dependencies were determined for chlorous acid self-decomposition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714089 [article] Reactions and kinetics of Cl(III) decomposition [texte imprimé] / Tuula Lehtimaa, Auteur ; Ville Tarvo, Auteur ; Gérard Mortha, Auteur . - 2008 . - p. 5284–5290. Bibliogr. p. 5289-5290 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5284–5290 Mots-clés : Chlorite acid  Chlorous Self-decomposition Résumé : Several pathways leading to the decomposition of chlorite and chlorous acid have been published. In this study, both experimental and computational approaches have been applied to clarify the authenticity of the different routes. The decomposition of chlorine (III), i.e. chlorous acid and chlorite, was monitored with iodometric titration at changing chloride concentrations, temperature, and existence of iron (III) at pH 1−3. Dimethylsulfoxide (DMSO) was used to prevent hypochlorous acid from reacting with chlorite. Chlorine dioxide was not formed in the absence of metals when hypochlorous acid and chlorine were trapped. The self-decomposition of Cl(III) proceeds only via the acidic form while chlorite is stable. Chloride ions enhanced the chlorous acid decomposition rate especially at low pH. Chlorite decomposes in the presence of Fe3+ ions. General kinetic parameters and their temperature dependencies were determined for chlorous acid self-decomposition. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714089

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Acyclic N-halamine coated Kevlar fabric materials / Jie Luo in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5291–5297 Titre : Acyclic N-halamine coated Kevlar fabric materials : preparation and biocidal functions Type de document : texte imprimé Auteurs : Jie Luo, Auteur ; Yuyu Sun, Auteur Année de publication : 2008 Article en page(s) : p. 5291–5297 Note générale : Bibliogr. p. 5296-5297 Langues : Anglais (eng) Mots-clés : Polymethacrylamide  Chlorine bleach treatment  Kevlar fabrics Résumé : Polymethacrylamide (PMAA) was coated onto the surfaces of Kevlar fabrics through the in situ polymerization of methacrylamide (MAA) within coating polymer binders. Upon chlorine bleach treatment, the amide groups of the coated PMAA side chains were transformed into stable acyclic N-halamines. The resultant fabric materials provided potent, durable, and rechargeable biocidal activities against E. coli (gram-negative bacteria), S. aureus (gram-positive bacteria), C. tropicalis (fungi), MS2 virus, and Bacillus subtilis spores. The excellent thermal and mechanical properties of the original Kevlar fabrics were successfully retained after the coating treatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800021p [article] Acyclic N-halamine coated Kevlar fabric materials : preparation and biocidal functions [texte imprimé] / Jie Luo, Auteur ; Yuyu Sun, Auteur . - 2008 . - p. 5291–5297. Bibliogr. p. 5296-5297 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5291–5297 Mots-clés : Polymethacrylamide  Chlorine bleach treatment  Kevlar fabrics Résumé : Polymethacrylamide (PMAA) was coated onto the surfaces of Kevlar fabrics through the in situ polymerization of methacrylamide (MAA) within coating polymer binders. Upon chlorine bleach treatment, the amide groups of the coated PMAA side chains were transformed into stable acyclic N-halamines. The resultant fabric materials provided potent, durable, and rechargeable biocidal activities against E. coli (gram-negative bacteria), S. aureus (gram-positive bacteria), C. tropicalis (fungi), MS2 virus, and Bacillus subtilis spores. The excellent thermal and mechanical properties of the original Kevlar fabrics were successfully retained after the coating treatment. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800021p

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SO3H-functionalized ionic liquids for selective alkylation of p-cresol with tert-butanol / Xiumei Liu in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5298–5303 Titre : SO3H-functionalized ionic liquids for selective alkylation of p-cresol with tert-butanol Type de document : texte imprimé Auteurs : Xiumei Liu, Auteur ; Jinxia Zhou, Auteur ; Xinwen Guo, Auteur ; Liu, Min, Auteur Année de publication : 2008 Article en page(s) : p. 5298–5303 Note générale : Bibliogr. p. 5303 Langues : Anglais (eng) Mots-clés : SO3H -- ionic liquids  Hammett method  p-cresol conversion  tert-Butanol Résumé : The SO3H-functionalized ionic liquids were synthesized by using pyridine and 1,4-butane or 1,3-propane sulfone as the source and characterized by NMR and time-of-flight mass spectrometry. The acidity of the ionic liquids determined by the Hammett method is almost the same as that of a conventional acid, such as H2SO4. The catalytic performance of ionic liquids for the tert-butylation of p-cresol with tert-butanol was evaluated; by using the ionic liquids as catalysts at the optimum reaction conditions, 79% of the p-cresol conversion and 92% of the selectivity to 2-tert-butyl-p-cresol can be obtained. The spent ionic liquid can be recovered and recycled. The possible mechanism for this reaction system was discussed based on the reaction results and the ab initio calculation results. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070647t [article] SO3H-functionalized ionic liquids for selective alkylation of p-cresol with tert-butanol [texte imprimé] / Xiumei Liu, Auteur ; Jinxia Zhou, Auteur ; Xinwen Guo, Auteur ; Liu, Min, Auteur . - 2008 . - p. 5298–5303. Bibliogr. p. 5303 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5298–5303 Mots-clés : SO3H -- ionic liquids  Hammett method  p-cresol conversion  tert-Butanol Résumé : The SO3H-functionalized ionic liquids were synthesized by using pyridine and 1,4-butane or 1,3-propane sulfone as the source and characterized by NMR and time-of-flight mass spectrometry. The acidity of the ionic liquids determined by the Hammett method is almost the same as that of a conventional acid, such as H2SO4. The catalytic performance of ionic liquids for the tert-butylation of p-cresol with tert-butanol was evaluated; by using the ionic liquids as catalysts at the optimum reaction conditions, 79% of the p-cresol conversion and 92% of the selectivity to 2-tert-butyl-p-cresol can be obtained. The spent ionic liquid can be recovered and recycled. The possible mechanism for this reaction system was discussed based on the reaction results and the ab initio calculation results. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070647t

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Catalytic performance of rhodium-based catalysts for CO preferential oxidation in H2-rich gases / Camilla Karnfelt in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5304–5312 Titre : Catalytic performance of rhodium-based catalysts for CO preferential oxidation in H2-rich gases Type de document : texte imprimé Auteurs : Camilla Karnfelt, Auteur ; Stefania Specchia, Auteur ; Guido Saracco, Auteur Année de publication : 2008 Article en page(s) : p. 5304–5312 Note générale : Bibliogr. p. 5311-5312 Langues : Anglais (eng) Mots-clés : Rhodium-based catalysts  CO preferential oxidation  Gas Résumé : CO preferential oxidation (CO-PROX) can lead to a reduction of the CO content in the hydrogen-rich gas derived from hydrocarbon re-forming down to at least 10 ppmv or below, so as to enable its direct feed to standard polymer electrolyte membrane fuel cells (PEM FCs). Rh-based catalysts supported on A zeolites (3A, 4A, and 5A), alumina, titania, and ceria were prepared and tested for potential application in CO-PROX operating over a temperature range compatible with PEM FCs (80−100 °C). Among the prepared catalysts, the 1% Rh-zeolite 3A catalyst, tested with a weight space velocity (WSV) of 0.66 N·L·min−1·gcat.−1, was found to be the most suitable one for the CO-PROX at low temperature: it reduced the inlet CO concentration below 10 ppmv within a temperature range of at least 80−120 °C without the appearance of undesirable side reactions. Tests at progressively lower O-to-CO feed ratio and the same WSV value were carried out for the sake of reducing H2 consumption and improving CO-PROX selectivity. For 1% Rh-3A zeolite the minimum λ value, ensuring a sufficiently wide temperature range of a nearly complete CO conversion at temperatures compatible with PEM FCs operation, was found to be equal to 3. Finally, to decrease the catalyst cost, the Rh load on the catalyst was tentatively reduced from 1 to 0.5%. A better distribution of the active element crystallites over the support surface was even obtained for this last catalyst. When operating at λ = 3 and at WSV = 0.66 N·L·min−1·gcat.−1, the 0.5% Rh-3A catalyst could effectively reduce the inlet CO concentration below 10 ppmv within a temperature range of 100−140 °C, without the appearance of undesired side reactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0713588 [article] Catalytic performance of rhodium-based catalysts for CO preferential oxidation in H2-rich gases [texte imprimé] / Camilla Karnfelt, Auteur ; Stefania Specchia, Auteur ; Guido Saracco, Auteur . - 2008 . - p. 5304–5312. Bibliogr. p. 5311-5312 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5304–5312 Mots-clés : Rhodium-based catalysts  CO preferential oxidation  Gas Résumé : CO preferential oxidation (CO-PROX) can lead to a reduction of the CO content in the hydrogen-rich gas derived from hydrocarbon re-forming down to at least 10 ppmv or below, so as to enable its direct feed to standard polymer electrolyte membrane fuel cells (PEM FCs). Rh-based catalysts supported on A zeolites (3A, 4A, and 5A), alumina, titania, and ceria were prepared and tested for potential application in CO-PROX operating over a temperature range compatible with PEM FCs (80−100 °C). Among the prepared catalysts, the 1% Rh-zeolite 3A catalyst, tested with a weight space velocity (WSV) of 0.66 N·L·min−1·gcat.−1, was found to be the most suitable one for the CO-PROX at low temperature: it reduced the inlet CO concentration below 10 ppmv within a temperature range of at least 80−120 °C without the appearance of undesirable side reactions. Tests at progressively lower O-to-CO feed ratio and the same WSV value were carried out for the sake of reducing H2 consumption and improving CO-PROX selectivity. For 1% Rh-3A zeolite the minimum λ value, ensuring a sufficiently wide temperature range of a nearly complete CO conversion at temperatures compatible with PEM FCs operation, was found to be equal to 3. Finally, to decrease the catalyst cost, the Rh load on the catalyst was tentatively reduced from 1 to 0.5%. A better distribution of the active element crystallites over the support surface was even obtained for this last catalyst. When operating at λ = 3 and at WSV = 0.66 N·L·min−1·gcat.−1, the 0.5% Rh-3A catalyst could effectively reduce the inlet CO concentration below 10 ppmv within a temperature range of 100−140 °C, without the appearance of undesired side reactions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0713588

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Reaction kinetics for the heterogeneously catalyzed esterification of succinic acid with ethanol / Aspi K. Kolah in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5313–5317 Titre : Reaction kinetics for the heterogeneously catalyzed esterification of succinic acid with ethanol Type de document : texte imprimé Auteurs : Aspi K. Kolah, Auteur ; Navinchandra S. Asthana, Auteur ; Dung T Vu, Auteur Année de publication : 2008 Article en page(s) : p. 5313–5317 Note générale : Bibliogr. p. 5316-5317 Langues : Anglais (eng) Mots-clés : Succinic acid -- sterification  Ethanol  Kinetic model Résumé : The reaction kinetics of the reversible esterification reaction of succinic acid with ethanol to form monoethyl and diethyl succinate are presented. The reaction was studied in batch isothermal experiments catalyzed by macroporous Amberlyst-15 ion-exchange resin. Experimental data were obtained between 78 and 120 °C at different mole ratios of ethanol to succinic acid and at ion-exchange resin catalyst concentrations from 1 to 5 wt % of solution. Kinetic modeling was performed using a pseudohomogeneous mole fraction model which acceptably fits the experimental data. The kinetic model is useful for the design and simulation of processes such as reactive distillation for diethyl succinate formation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0706616 [article] Reaction kinetics for the heterogeneously catalyzed esterification of succinic acid with ethanol [texte imprimé] / Aspi K. Kolah, Auteur ; Navinchandra S. Asthana, Auteur ; Dung T Vu, Auteur . - 2008 . - p. 5313–5317. Bibliogr. p. 5316-5317 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5313–5317 Mots-clés : Succinic acid -- sterification  Ethanol  Kinetic model Résumé : The reaction kinetics of the reversible esterification reaction of succinic acid with ethanol to form monoethyl and diethyl succinate are presented. The reaction was studied in batch isothermal experiments catalyzed by macroporous Amberlyst-15 ion-exchange resin. Experimental data were obtained between 78 and 120 °C at different mole ratios of ethanol to succinic acid and at ion-exchange resin catalyst concentrations from 1 to 5 wt % of solution. Kinetic modeling was performed using a pseudohomogeneous mole fraction model which acceptably fits the experimental data. The kinetic model is useful for the design and simulation of processes such as reactive distillation for diethyl succinate formation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0706616

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Kinetics of cyanuric chloride hydrolysis in aqueous solution / Zhi Yan in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5318–5322 Titre : Kinetics of cyanuric chloride hydrolysis in aqueous solution Type de document : texte imprimé Auteurs : Zhi Yan, Auteur ; Wei-Lan Xue, Auteur ; Zuo-Xiang Zeng, Auteur Année de publication : 2008 Article en page(s) : p. 5318–5322 Note générale : Bibliogr. p. 5321-5322 Langues : Anglais (eng) Mots-clés : Cyanuric chloride  Hydrolysis reaction  Aqueous solution Résumé : The hydrolysis of cyanuric chloride is investigated as a function of temperature, pH, and cyanuric chloride concentration in liquid phase. The hydrolysis reaction is carried out in water or acetone/water system in the temperature range of 283.15−303.15 K. The hydrolysis rates of cyanuric chloride are monitored at different temperatures and at various pHs. The experiment data show that the hydrolysis rates are independent of pH value when pH ≤ 6, and increase with the pH value when pH ≥ 7. On the basis of the results, it is supposed that the hydrolysis reaction takes place by the unimolecular nucleophilic substitution (SN1) mechanism when pH ≤ 6 and by the bimolecular nucleophilic substitution (SN2) mechanism when pH ≥ 7. Kinetics models corresponding to the mechanisms are proposed as follow: −d(nA/v)/dt = 7.625 × 109e−69298/RTcA for the acidic situation and −d(nA/v)/dt = 7.112 × 1011e−59267/RTcAcB0.5 for the alkaline situation. Experiment data show that the models work well with the average deviations of 2.01% and 9.88%, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071289x [article] Kinetics of cyanuric chloride hydrolysis in aqueous solution [texte imprimé] / Zhi Yan, Auteur ; Wei-Lan Xue, Auteur ; Zuo-Xiang Zeng, Auteur . - 2008 . - p. 5318–5322. Bibliogr. p. 5321-5322 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5318–5322 Mots-clés : Cyanuric chloride  Hydrolysis reaction  Aqueous solution Résumé : The hydrolysis of cyanuric chloride is investigated as a function of temperature, pH, and cyanuric chloride concentration in liquid phase. The hydrolysis reaction is carried out in water or acetone/water system in the temperature range of 283.15−303.15 K. The hydrolysis rates of cyanuric chloride are monitored at different temperatures and at various pHs. The experiment data show that the hydrolysis rates are independent of pH value when pH ≤ 6, and increase with the pH value when pH ≥ 7. On the basis of the results, it is supposed that the hydrolysis reaction takes place by the unimolecular nucleophilic substitution (SN1) mechanism when pH ≤ 6 and by the bimolecular nucleophilic substitution (SN2) mechanism when pH ≥ 7. Kinetics models corresponding to the mechanisms are proposed as follow: −d(nA/v)/dt = 7.625 × 109e−69298/RTcA for the acidic situation and −d(nA/v)/dt = 7.112 × 1011e−59267/RTcAcB0.5 for the alkaline situation. Experiment data show that the models work well with the average deviations of 2.01% and 9.88%, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071289x

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Determination of critical speed for complete solid suspension using acoustic emission method based on multiscale analysis in stirred tank / Ren Congjing in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5323–5327 Titre : Determination of critical speed for complete solid suspension using acoustic emission method based on multiscale analysis in stirred tank Type de document : texte imprimé Auteurs : Ren Congjing, Auteur ; Xiaojing Jiang, Auteur ; Wang Jingdai, Auteur ; Yongrong Yang, Auteur Année de publication : 2008 Article en page(s) : p. 5323–5327 Note générale : Bibliogr. p. 5327 Langues : Anglais (eng) Mots-clés : Solid suspension  Acoustic emission  Stirred tank  Multiscale analysis Résumé : According to the mechanism that acoustic emission (AE) signals with different frequency ranges were emitted when solid particles impacted the wall, a characteristic scale (S1) of the AE signals representing the movement of solid particles was obtained by using wavelet transform and Hurst analysis. A regular evolution behavior of energy fraction on each frequency with the increasing impeller speeds was observed. A new method to determine critical impeller speed was presented by analyzing the relationship between energy fraction in S1 scale and the impeller speed. The critical impeller speed was associated with the emergence of steady state in energy fractions in the S1 scale. The method was further verified with four groups of experiments with the particle sizes of 0.5 mm and 0.7 mm by comparing experimental results with that from the conventional visual method for a water and glass beads system. The average relative errors were no more than 4.28%. It is a fast, nonintrusive, and accurate method to investigate the Njs by multiscale analysis of acoustic energy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714347 [article] Determination of critical speed for complete solid suspension using acoustic emission method based on multiscale analysis in stirred tank [texte imprimé] / Ren Congjing, Auteur ; Xiaojing Jiang, Auteur ; Wang Jingdai, Auteur ; Yongrong Yang, Auteur . - 2008 . - p. 5323–5327. Bibliogr. p. 5327 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5323–5327 Mots-clés : Solid suspension  Acoustic emission  Stirred tank  Multiscale analysis Résumé : According to the mechanism that acoustic emission (AE) signals with different frequency ranges were emitted when solid particles impacted the wall, a characteristic scale (S1) of the AE signals representing the movement of solid particles was obtained by using wavelet transform and Hurst analysis. A regular evolution behavior of energy fraction on each frequency with the increasing impeller speeds was observed. A new method to determine critical impeller speed was presented by analyzing the relationship between energy fraction in S1 scale and the impeller speed. The critical impeller speed was associated with the emergence of steady state in energy fractions in the S1 scale. The method was further verified with four groups of experiments with the particle sizes of 0.5 mm and 0.7 mm by comparing experimental results with that from the conventional visual method for a water and glass beads system. The average relative errors were no more than 4.28%. It is a fast, nonintrusive, and accurate method to investigate the Njs by multiscale analysis of acoustic energy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714347

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Pyrolytic decarboxylation and cracking of stearic acid / Kelly D. Maher in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5328–5336 Titre : Pyrolytic decarboxylation and cracking of stearic acid Type de document : texte imprimé Auteurs : Kelly D. Maher, Auteur ; Kathlyn M. Kirkwood, Auteur ; Murray R. Gray, Auteur ; David C. Bressler, Auteur Année de publication : 2008 Article en page(s) : p. 5328–5336 Note générale : Bibliogr. p. 5335-5336 Langues : Anglais (eng) Mots-clés : Fatty acids -- pyrolytic conversion  Decarboxylation  Stearic acid Résumé : The primary objective of this work was to study the pyrolytic conversion of fatty acids to produce deoxygenated, liquid hydrocarbon products for use as renewable chemicals or fuels. Stearic acid (n-octadecanoic acid) was chosen as a model compound for the free fatty acids liberated through the hydrolysis of beef tallow. Batch pyrolysis of stearic acid was conducted over a range of temperatures and times, and the reaction products were extracted and identified through gas chromatography and mass spectrometry. Under mild conditions, n-heptadecane was the main product, with concurrent production of CO2, showing that decarboxylation was likely the first reaction to occur. Distinct series of n-alkanes and 1-alkenes developed and shifted to lower carbon numbers with increased temperature and time, consistent with hydrocarbon cracking reactions. Eventually, the series decomposed to aromatics, insoluble solids, and unidentified low-molecular-weight species. Semiquantitative analysis of the chromatographic data confirmed the predominance of n-heptadecane in the product mixture, the development and decomposition of the aliphatic species, the selectivity for n-alkanes over 1-alkenes, and the shift in product distribution toward lower carbon numbers. This work demonstrates the feasibility of producing liquid hydrocarbons through the pyrolysis of free fatty acids hydrolyzed from lipid feeds. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714551 [article] Pyrolytic decarboxylation and cracking of stearic acid [texte imprimé] / Kelly D. Maher, Auteur ; Kathlyn M. Kirkwood, Auteur ; Murray R. Gray, Auteur ; David C. Bressler, Auteur . - 2008 . - p. 5328–5336. Bibliogr. p. 5335-5336 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5328–5336 Mots-clés : Fatty acids -- pyrolytic conversion  Decarboxylation  Stearic acid Résumé : The primary objective of this work was to study the pyrolytic conversion of fatty acids to produce deoxygenated, liquid hydrocarbon products for use as renewable chemicals or fuels. Stearic acid (n-octadecanoic acid) was chosen as a model compound for the free fatty acids liberated through the hydrolysis of beef tallow. Batch pyrolysis of stearic acid was conducted over a range of temperatures and times, and the reaction products were extracted and identified through gas chromatography and mass spectrometry. Under mild conditions, n-heptadecane was the main product, with concurrent production of CO2, showing that decarboxylation was likely the first reaction to occur. Distinct series of n-alkanes and 1-alkenes developed and shifted to lower carbon numbers with increased temperature and time, consistent with hydrocarbon cracking reactions. Eventually, the series decomposed to aromatics, insoluble solids, and unidentified low-molecular-weight species. Semiquantitative analysis of the chromatographic data confirmed the predominance of n-heptadecane in the product mixture, the development and decomposition of the aliphatic species, the selectivity for n-alkanes over 1-alkenes, and the shift in product distribution toward lower carbon numbers. This work demonstrates the feasibility of producing liquid hydrocarbons through the pyrolysis of free fatty acids hydrolyzed from lipid feeds. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714551

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Volatile fatty acid anaerobic degradation / Karina Boltes in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5337 - 5345 Titre : Volatile fatty acid anaerobic degradation : kinetic modeling with an inoculum under controlled conditions Type de document : texte imprimé Auteurs : Karina Boltes, Auteur ; Pedro Leton, Auteur ; Eloy Garcia-Calvo, Auteur Année de publication : 2008 Article en page(s) : p. 5337 - 5345 Note générale : Bibliogr. p. 5344-3546 Langues : Anglais (eng) Mots-clés : Organic matter -- anaerobic degradation  Kinetic study Résumé : Due to the multiple reactions that are involved, the mathematical description of anaerobic degradation of organic matter is normally complicated. Several efforts have been made for the development of the ADM1 model, that cover the major processes involved in complex organic substrate conversion. This model application requires a large number of constants and coefficients, which were proposed, reviewed the information available at the time of their publication. The more recent published papers about ADM1 model application report a necessary revision of the kinetic parameters used for volatile fatty acid (VFA) degradation. This work presents a kinetic study of VFA anaerobic degradation performed in batch and continuous stirred tank reactor. Acetic, propionic, and butyric acids (mixed in a ratio 2:1:1 COD basis) and acetic acid only were used as substrate. The biomass for kinetics assays was previously produced in a codigestion process using pig manure mixed with sewage sludge obtained from anaerobic municipal digester. The inoculum build-up and maintenance were conducted in a laboratory stirred tank digester, under controlled conditions to avoid any variability of the resulting parameters obtained. Moreover, the black box approximation was applied in order to reduce the number of parameters for a complete description. A set of lineal relations was obtained to estimate methane, carbon dioxide, and mixed biomass production rates, from VFA degradation rates only. Finally, a good simulation of experimental data was obtained for VFAs, biomass, methane, and carbon dioxide both in continuous and batch operation modes. [article] Volatile fatty acid anaerobic degradation : kinetic modeling with an inoculum under controlled conditions [texte imprimé] / Karina Boltes, Auteur ; Pedro Leton, Auteur ; Eloy Garcia-Calvo, Auteur . - 2008 . - p. 5337 - 5345. Bibliogr. p. 5344-3546 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5337 - 5345 Mots-clés : Organic matter -- anaerobic degradation  Kinetic study Résumé : Due to the multiple reactions that are involved, the mathematical description of anaerobic degradation of organic matter is normally complicated. Several efforts have been made for the development of the ADM1 model, that cover the major processes involved in complex organic substrate conversion. This model application requires a large number of constants and coefficients, which were proposed, reviewed the information available at the time of their publication. The more recent published papers about ADM1 model application report a necessary revision of the kinetic parameters used for volatile fatty acid (VFA) degradation. This work presents a kinetic study of VFA anaerobic degradation performed in batch and continuous stirred tank reactor. Acetic, propionic, and butyric acids (mixed in a ratio 2:1:1 COD basis) and acetic acid only were used as substrate. The biomass for kinetics assays was previously produced in a codigestion process using pig manure mixed with sewage sludge obtained from anaerobic municipal digester. The inoculum build-up and maintenance were conducted in a laboratory stirred tank digester, under controlled conditions to avoid any variability of the resulting parameters obtained. Moreover, the black box approximation was applied in order to reduce the number of parameters for a complete description. A set of lineal relations was obtained to estimate methane, carbon dioxide, and mixed biomass production rates, from VFA degradation rates only. Finally, a good simulation of experimental data was obtained for VFAs, biomass, methane, and carbon dioxide both in continuous and batch operation modes.

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Activity of mesoporous alumina particles for biomass steam reforming in a fluidized-bed reactor and its application to a dual-gas-flow two-stage reactor system / Sou Hosoka in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5346–5352 Titre : Activity of mesoporous alumina particles for biomass steam reforming in a fluidized-bed reactor and its application to a dual-gas-flow two-stage reactor system Type de document : texte imprimé Auteurs : Sou Hosoka, Auteur ; Makiyo Sugawa, Auteur ; Koyo Norinaga, Auteur ; Chun-Zhu Li, Auteur Année de publication : 2008 Article en page(s) : p. 5346–5352 Note générale : Bibliogr. p. 5351-5352 Langues : Anglais (eng) Mots-clés : Alumina particles  Fluidized-bed reactor  Dual-gas-flow two-stage gasification Résumé : Pulverized sugar cane bagasse (SCB) and cedar sawdust (CSD) were rapidly pyrolyzed and reformed in situ with steam in a laboratory-scale fluidized-bed reactor at temperature of 973−1123 K and steam-to-biomass mass ratio (S/B) of 0−3.5. A substantial portion of the nascent tar was converted into coke over fluidized mesoporous γ-alumina (MPGA) used as the bed material. The coke was sufficiently active to completely eliminate tar except for BTX (benzene, toluene, xylene) and naphthalene derivatives. Experimental results were used for simulating a dual-gas-flow two-stage gasification in which MPGA circulates through the reformer for producing syngas and the combustor for producing heat by burning the coke and char. The simulation predicted maximum cold gas efficiencies over 0.8 on an LHV basis for both SCB and CSD at temperature of 1073−1123 K and S/B of 0.7−0.8. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071655c [article] Activity of mesoporous alumina particles for biomass steam reforming in a fluidized-bed reactor and its application to a dual-gas-flow two-stage reactor system [texte imprimé] / Sou Hosoka, Auteur ; Makiyo Sugawa, Auteur ; Koyo Norinaga, Auteur ; Chun-Zhu Li, Auteur . - 2008 . - p. 5346–5352. Bibliogr. p. 5351-5352 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5346–5352 Mots-clés : Alumina particles  Fluidized-bed reactor  Dual-gas-flow two-stage gasification Résumé : Pulverized sugar cane bagasse (SCB) and cedar sawdust (CSD) were rapidly pyrolyzed and reformed in situ with steam in a laboratory-scale fluidized-bed reactor at temperature of 973−1123 K and steam-to-biomass mass ratio (S/B) of 0−3.5. A substantial portion of the nascent tar was converted into coke over fluidized mesoporous γ-alumina (MPGA) used as the bed material. The coke was sufficiently active to completely eliminate tar except for BTX (benzene, toluene, xylene) and naphthalene derivatives. Experimental results were used for simulating a dual-gas-flow two-stage gasification in which MPGA circulates through the reformer for producing syngas and the combustor for producing heat by burning the coke and char. The simulation predicted maximum cold gas efficiencies over 0.8 on an LHV basis for both SCB and CSD at temperature of 1073−1123 K and S/B of 0.7−0.8. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071655c

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Solvent effect in homogeneous and heterogeneous reactions to remove dibenzothiophene by an oxidation-extraction scheme / Luis F. Ramirez-Verduzco in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5353–5361 Titre : Solvent effect in homogeneous and heterogeneous reactions to remove dibenzothiophene by an oxidation-extraction scheme Type de document : texte imprimé Auteurs : Luis F. Ramirez-Verduzco, Auteur ; J. A. De los Reyes, Auteur ; E. Torres-Garcia, Auteur Année de publication : 2008 Article en page(s) : p. 5353–5361 Note générale : Bibliogr. p. 5360-5361 Langues : Anglais (eng) Mots-clés : Dibenzothiophene -- oxidation−  extraction scheme  Heterogeneous reactions  Homogeneous reactions Résumé : In this work a study of dibenzothiophene removal by an oxidation−extraction scheme is presented. Experiments were carried out to observe the role that the solvent plays during the process, as well as the oxidizing agent and catalyst. The oxidation was carried out with hydrogen peroxide in the presence of a catalyst of tungsten supported on zirconia (WOx−ZrO2). A dibenzothiophene + n-hexadecane model mixture was employed to simulate a diesel fuel. Methanol, ethanol, acetonitrile, and γ-butyrolactone were used as extraction solvents. Dibenzothiophene (DBT) was removed more efficiently by γ-butyrolactone with respect to other solvents. The highest reactivity was achieved when γ-butyrolactone was used during DBT oxidation with and without catalyst. When oxidation was carried out without catalyst, the oxidant behavior of the mixture could be explained in terms of the dissociation of hydrogen peroxide to produce strong oxidant species such as perhydroxyl ions (HO2−) by the influence of the aprotic solvents. Finally, when a catalyst was used during the oxidation, there was an additional oxidation contribution through the formation of surface peroxo−metal intermediates (W−O−O−H). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701692r [article] Solvent effect in homogeneous and heterogeneous reactions to remove dibenzothiophene by an oxidation-extraction scheme [texte imprimé] / Luis F. Ramirez-Verduzco, Auteur ; J. A. De los Reyes, Auteur ; E. Torres-Garcia, Auteur . - 2008 . - p. 5353–5361. Bibliogr. p. 5360-5361 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5353–5361 Mots-clés : Dibenzothiophene -- oxidation−  extraction scheme  Heterogeneous reactions  Homogeneous reactions Résumé : In this work a study of dibenzothiophene removal by an oxidation−extraction scheme is presented. Experiments were carried out to observe the role that the solvent plays during the process, as well as the oxidizing agent and catalyst. The oxidation was carried out with hydrogen peroxide in the presence of a catalyst of tungsten supported on zirconia (WOx−ZrO2). A dibenzothiophene + n-hexadecane model mixture was employed to simulate a diesel fuel. Methanol, ethanol, acetonitrile, and γ-butyrolactone were used as extraction solvents. Dibenzothiophene (DBT) was removed more efficiently by γ-butyrolactone with respect to other solvents. The highest reactivity was achieved when γ-butyrolactone was used during DBT oxidation with and without catalyst. When oxidation was carried out without catalyst, the oxidant behavior of the mixture could be explained in terms of the dissociation of hydrogen peroxide to produce strong oxidant species such as perhydroxyl ions (HO2−) by the influence of the aprotic solvents. Finally, when a catalyst was used during the oxidation, there was an additional oxidation contribution through the formation of surface peroxo−metal intermediates (W−O−O−H). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie701692r

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Hydrodechlorination of chlorobenzene over silica-supported nickel phosphide catalysts / Xuguang Liu in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5362–5368 Titre : Hydrodechlorination of chlorobenzene over silica-supported nickel phosphide catalysts Type de document : texte imprimé Auteurs : Xuguang Liu, Auteur ; Jixiang Chen, Auteur ; Jiyan Zhang, Auteur Année de publication : 2008 Article en page(s) : p. 5362–5368 Note générale : Bibliogr. p. 5367-5368 Langues : Anglais (eng) Mots-clés : Chlorobenzene -- hydrodechlorination  Nickel phosphate catalysts Résumé : Silica-supported Ni3P, Ni12P5, and Ni2P catalysts were prepared by the temperature-programmed reduction method from nickel phosphate precursors. A Ni/SiO2 catalyst was also prepared as a reference. The effect of the initial Ni/P molar ratio in the precursor on the catalyst structure and hydrodechlorination performance was investigated. The physicochemical properties of the catalysts were characterized by means of N2 adsorption, hydrogen temperature-programmed reduction, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet and visible spectroscopy, hydrogen temperature-programmed desorption, and inductively coupled plasma spectroscopy. The catalyst activities in the hydrodechlorination of chlorobenzene were evaluated in a fixed-bed reactor at atmospheric pressure. The silica-supported nickel phosphides exhibited superior hydrodechlorination activities to that of supported nickel. This can be attributed to the special physicochemical properties of nickel phosphides and a great amount of spillover hydrogen species. In nickel phosphides, there is a small amount of electron transfer from Ni to P, leading to a small positive charge on Ni. This favors a weakening of the interaction between chlorine and nickel sites, as well as between adsorbed hydrogen species and nickel phosphides. The “ensemble effect” of P is also beneficial in decreasing the coverage of chlorine on nickel sites. Because of the reduced interaction between adsorbed hydrogen species and nickel phosphides, the energy barrier of the hydrogen spillover on the silica-supported nickel phosphide catalysts decreases, which accounts for the increased amount of spillover hydrogen species on the catalyst surface. Spillover hydrogen species not only promote the hydrogenolysis of the C−Cl bond, but also favor the removal of chlorine ions from the surface of the catalysts. Hydrodechlorination over the nickel phosphide catalysts is characterized by a reaction induction period that becomes longer with increasing phosphorus content in the catalyst precursor. This is related to the blocking of active sites by excess phosphorus. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017542 [article] Hydrodechlorination of chlorobenzene over silica-supported nickel phosphide catalysts [texte imprimé] / Xuguang Liu, Auteur ; Jixiang Chen, Auteur ; Jiyan Zhang, Auteur . - 2008 . - p. 5362–5368. Bibliogr. p. 5367-5368 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5362–5368 Mots-clés : Chlorobenzene -- hydrodechlorination  Nickel phosphate catalysts Résumé : Silica-supported Ni3P, Ni12P5, and Ni2P catalysts were prepared by the temperature-programmed reduction method from nickel phosphate precursors. A Ni/SiO2 catalyst was also prepared as a reference. The effect of the initial Ni/P molar ratio in the precursor on the catalyst structure and hydrodechlorination performance was investigated. The physicochemical properties of the catalysts were characterized by means of N2 adsorption, hydrogen temperature-programmed reduction, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet and visible spectroscopy, hydrogen temperature-programmed desorption, and inductively coupled plasma spectroscopy. The catalyst activities in the hydrodechlorination of chlorobenzene were evaluated in a fixed-bed reactor at atmospheric pressure. The silica-supported nickel phosphides exhibited superior hydrodechlorination activities to that of supported nickel. This can be attributed to the special physicochemical properties of nickel phosphides and a great amount of spillover hydrogen species. In nickel phosphides, there is a small amount of electron transfer from Ni to P, leading to a small positive charge on Ni. This favors a weakening of the interaction between chlorine and nickel sites, as well as between adsorbed hydrogen species and nickel phosphides. The “ensemble effect” of P is also beneficial in decreasing the coverage of chlorine on nickel sites. Because of the reduced interaction between adsorbed hydrogen species and nickel phosphides, the energy barrier of the hydrogen spillover on the silica-supported nickel phosphide catalysts decreases, which accounts for the increased amount of spillover hydrogen species on the catalyst surface. Spillover hydrogen species not only promote the hydrogenolysis of the C−Cl bond, but also favor the removal of chlorine ions from the surface of the catalysts. Hydrodechlorination over the nickel phosphide catalysts is characterized by a reaction induction period that becomes longer with increasing phosphorus content in the catalyst precursor. This is related to the blocking of active sites by excess phosphorus. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017542

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Effect of catalysts supporting on tandem polymerization of ethylene stock in synthesis ofethylene-1-hexene copolymer / Junwei Zhang in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5369-5375 Titre : Effect of catalysts supporting on tandem polymerization of ethylene stock in synthesis ofethylene-1-hexene copolymer Type de document : texte imprimé Auteurs : Junwei Zhang, Auteur ; Hong Fan, Auteur ; Bo-Geng Li, Auteur ; Shiping Zhu, Auteur Année de publication : 2008 Article en page(s) : p. 5369-5375 Note générale : Bibliogr. p. 5374-5375 Langues : Anglais (eng) Mots-clés : Ethylene stock  Copolymérisation  polyéthylène Résumé : Ethylene-1-hexene copolymers were synthesized with a tandem catalysis system consisting of a new trimerization catalyst (1), bis(2-dodecylsulfanylethyl)amine-CrCl3, and a copolymerization catalyst (2), Et(Ind)2ZrCl2. Catalysts 1 and 2 were supported on silica particles, and the effects of different supporting strategies on trimerization selectivity, 1-hexene incorporation efficiency, and copolymerization activity were studied and compared to the homogeneous system. It was found that the supported 1 trimerized ethylene with a similar selectivity (>99%) but one-quarter of the activity of the homogeneous 1. The supported 2 gave 40% 1-hexene incorporation efficiency and one-third of the copolymerization activity of the homogeneous 2. The tandem action of the supported 1 and 2 yielded linear low-density polyethylene (LLDPE) materials that contained only C4 side-chains. The dual supported system had activities at a 107 g/(mol Zr h) level, in the same order of the homogeneous counterpart. Adjusting the Cr/Zr ratio yielded various branching densities and, thus, melting temperatures of the resulting polymers. The samples prepared with the supported 2 exhibited broad differential scanning calorimetry (DSC) curves, probably due to multiple active sites. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017564 [article] Effect of catalysts supporting on tandem polymerization of ethylene stock in synthesis ofethylene-1-hexene copolymer [texte imprimé] / Junwei Zhang, Auteur ; Hong Fan, Auteur ; Bo-Geng Li, Auteur ; Shiping Zhu, Auteur . - 2008 . - p. 5369-5375. Bibliogr. p. 5374-5375 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5369-5375 Mots-clés : Ethylene stock  Copolymérisation  polyéthylène Résumé : Ethylene-1-hexene copolymers were synthesized with a tandem catalysis system consisting of a new trimerization catalyst (1), bis(2-dodecylsulfanylethyl)amine-CrCl3, and a copolymerization catalyst (2), Et(Ind)2ZrCl2. Catalysts 1 and 2 were supported on silica particles, and the effects of different supporting strategies on trimerization selectivity, 1-hexene incorporation efficiency, and copolymerization activity were studied and compared to the homogeneous system. It was found that the supported 1 trimerized ethylene with a similar selectivity (>99%) but one-quarter of the activity of the homogeneous 1. The supported 2 gave 40% 1-hexene incorporation efficiency and one-third of the copolymerization activity of the homogeneous 2. The tandem action of the supported 1 and 2 yielded linear low-density polyethylene (LLDPE) materials that contained only C4 side-chains. The dual supported system had activities at a 107 g/(mol Zr h) level, in the same order of the homogeneous counterpart. Adjusting the Cr/Zr ratio yielded various branching densities and, thus, melting temperatures of the resulting polymers. The samples prepared with the supported 2 exhibited broad differential scanning calorimetry (DSC) curves, probably due to multiple active sites. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017564

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Sewage sludge pyrolysis in fluidized bed / Isabel Fonts in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5376-5385 Titre : Sewage sludge pyrolysis in fluidized bed : 1. Influence of operational conditions on the product distribution Type de document : texte imprimé Auteurs : Isabel Fonts, Auteur ; Alfonso Juan, Auteur ; Gloria Gea, Auteur ; María B Murillo, Auteur Année de publication : 2008 Article en page(s) : p. 5376-5385 Note générale : Bibliogr. p. 5384-5385 Langues : Anglais (eng) Mots-clés : Sewage sludge -- fluidized bed  Pyrolysis Products Résumé : In this work, pyrolysis of sewage sludge in a fluidized bed was studied experimentally in order to obtain a liquid product able to be used in energetic applications. The influence of operational conditions on the product distribution was studied. The operational variables were as follows: temperature (450-650 °C), nitrogen flow rate (3.5-5.5 L(NTP) min-1), and solid feed rate (3.0-6.0 g min-1). Their influence was considered on the yields to the three pyrolysis products: solid, liquid, and gas. The liquid yield was mainly influenced by the bed temperature but also by the nitrogen flow rate and the solid feed rate. The bed temperature and the nitrogen flow rate showed a quadratic effect, and the maximum liquid yield was achieved at around 540 °C and around 4.5 L(NTP) min-1 of nitrogen. The solid feed rate just affected on the liquid yield at the lower temperatures studied, and the maximum liquid yield was obtained at the lowest solid feed rates. The design of experiments (DOE) statistical tool was used in the preparation of the work. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017788 [article] Sewage sludge pyrolysis in fluidized bed : 1. Influence of operational conditions on the product distribution [texte imprimé] / Isabel Fonts, Auteur ; Alfonso Juan, Auteur ; Gloria Gea, Auteur ; María B Murillo, Auteur . - 2008 . - p. 5376-5385. Bibliogr. p. 5384-5385 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5376-5385 Mots-clés : Sewage sludge -- fluidized bed  Pyrolysis Products Résumé : In this work, pyrolysis of sewage sludge in a fluidized bed was studied experimentally in order to obtain a liquid product able to be used in energetic applications. The influence of operational conditions on the product distribution was studied. The operational variables were as follows: temperature (450-650 °C), nitrogen flow rate (3.5-5.5 L(NTP) min-1), and solid feed rate (3.0-6.0 g min-1). Their influence was considered on the yields to the three pyrolysis products: solid, liquid, and gas. The liquid yield was mainly influenced by the bed temperature but also by the nitrogen flow rate and the solid feed rate. The bed temperature and the nitrogen flow rate showed a quadratic effect, and the maximum liquid yield was achieved at around 540 °C and around 4.5 L(NTP) min-1 of nitrogen. The solid feed rate just affected on the liquid yield at the lower temperatures studied, and the maximum liquid yield was obtained at the lowest solid feed rates. The design of experiments (DOE) statistical tool was used in the preparation of the work. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie7017788

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Mass transfer in a viscous bubble column with forced oscillations / Y. G. Waghmare in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5386-5394 Titre : Mass transfer in a viscous bubble column with forced oscillations Type de document : texte imprimé Auteurs : Y. G. Waghmare, Auteur ; Richard G. Rice, Auteur ; F Carl Knopf, Auteur Année de publication : 2008 Article en page(s) : p. 5386-5394 Note générale : Bibliogr. p. 5394 Langues : Anglais (eng) Mots-clés : Viscous bubble column  Oscillations -- mass transfer  carboxymethylcellulose solutions Résumé : Previously, it was shown that low-amplitude (0.5−2.5 mm) oscillations at moderate frequencies (0−25 Hz) can be used to improve bubble column performance. Literature on pulsed-flow bubble columns has mainly focused on air−water systems. In the present work, the effects of oscillations on mass transfer in a pulsed-flow bubble column were studied for various carboxymethylcellulose solutions giving an effective viscosity range of 1−62 cP. As in our previous work on air−water systems, the viscous system exhibits an initial increase in mass-transfer coefficient as a function of frequency and then leveled to a plateau. This asymptotic behavior can be attributed to the Bjerknes force acting on a bubble, which slows the bubble rise as frequency is increased. The shape of the curve for mass-transfer coefficient vs frequency was unchanged for viscous systems, but the absolute value of the mass-transfer coefficient decreased as a function of increasing viscosity. A theory was developed from first principles to show how the volumetric mass-transfer coefficient changes as a function of operating parameters, such as the frequency and amplitude of vibrations, gas superficial velocity, and viscosity of the fluid. The comparison with experiments was quite good for a large range of velocities and viscosities. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800041k [article] Mass transfer in a viscous bubble column with forced oscillations [texte imprimé] / Y. G. Waghmare, Auteur ; Richard G. Rice, Auteur ; F Carl Knopf, Auteur . - 2008 . - p. 5386-5394. Bibliogr. p. 5394 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5386-5394 Mots-clés : Viscous bubble column  Oscillations -- mass transfer  carboxymethylcellulose solutions Résumé : Previously, it was shown that low-amplitude (0.5−2.5 mm) oscillations at moderate frequencies (0−25 Hz) can be used to improve bubble column performance. Literature on pulsed-flow bubble columns has mainly focused on air−water systems. In the present work, the effects of oscillations on mass transfer in a pulsed-flow bubble column were studied for various carboxymethylcellulose solutions giving an effective viscosity range of 1−62 cP. As in our previous work on air−water systems, the viscous system exhibits an initial increase in mass-transfer coefficient as a function of frequency and then leveled to a plateau. This asymptotic behavior can be attributed to the Bjerknes force acting on a bubble, which slows the bubble rise as frequency is increased. The shape of the curve for mass-transfer coefficient vs frequency was unchanged for viscous systems, but the absolute value of the mass-transfer coefficient decreased as a function of increasing viscosity. A theory was developed from first principles to show how the volumetric mass-transfer coefficient changes as a function of operating parameters, such as the frequency and amplitude of vibrations, gas superficial velocity, and viscosity of the fluid. The comparison with experiments was quite good for a large range of velocities and viscosities. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800041k

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Designing nanostructured membranes for oxidative dehydrogenation of alkanes using kinetic modeling / Simón E Albo in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5395-5401 Titre : Designing nanostructured membranes for oxidative dehydrogenation of alkanes using kinetic modeling Type de document : texte imprimé Auteurs : Simón E Albo, Auteur ; Randall Q. Snurr, Auteur ; Linda J. Broadbelt, Auteur Année de publication : 2008 Article en page(s) : p. 5395-5401 Note générale : Bibliogr. p. 5401 Langues : Anglais (eng) Mots-clés : Nanostructured membranes -- ethane  Oxidative dehydrogenation  Sweep-gas mode  Pass-through mode Résumé : Continuum-level modeling and Knudsen dynamics simulations were used to investigate the oxidative dehydrogenation of ethane in nanostructured membranes. Different operational modes were investigated, including pass-through and sweep-gas modes, and pores with total and partial catalyst coverage on the walls were studied. It was determined that by adjusting the aspect ratio (L/d) of the pore in the pass-through mode it is possible to achieve high conversions and yields even for slow reactions. On the other hand, in the sweep-gas mode, the velocity of the reaction limits the conversion and yield that can be achieved. It was also found that, under Knudsen diffusion, covering the wall of the pores only partially with catalyst could improve the per gram conversion obtained. However, it does not improve the selectivity achieved for a given conversion when compared to that obtained in a pore fully covered in catalyst. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800043f [article] Designing nanostructured membranes for oxidative dehydrogenation of alkanes using kinetic modeling [texte imprimé] / Simón E Albo, Auteur ; Randall Q. Snurr, Auteur ; Linda J. Broadbelt, Auteur . - 2008 . - p. 5395-5401. Bibliogr. p. 5401 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5395-5401 Mots-clés : Nanostructured membranes -- ethane  Oxidative dehydrogenation  Sweep-gas mode  Pass-through mode Résumé : Continuum-level modeling and Knudsen dynamics simulations were used to investigate the oxidative dehydrogenation of ethane in nanostructured membranes. Different operational modes were investigated, including pass-through and sweep-gas modes, and pores with total and partial catalyst coverage on the walls were studied. It was determined that by adjusting the aspect ratio (L/d) of the pore in the pass-through mode it is possible to achieve high conversions and yields even for slow reactions. On the other hand, in the sweep-gas mode, the velocity of the reaction limits the conversion and yield that can be achieved. It was also found that, under Knudsen diffusion, covering the wall of the pores only partially with catalyst could improve the per gram conversion obtained. However, it does not improve the selectivity achieved for a given conversion when compared to that obtained in a pore fully covered in catalyst. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800043f

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Skeletal isomerization of butene in fixed beds. 1. experimental investigation and structure-performance effects / Matias Kangas in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5402–5412 Titre : Skeletal isomerization of butene in fixed beds. 1. experimental investigation and structure-performance effects Type de document : texte imprimé Auteurs : Matias Kangas, Auteur ; Narendra Kumar, Auteur ; Elina Harlin, Auteur Année de publication : 2008 Article en page(s) : p. 5402–5412 Note générale : Bibliogr. p. 5412 Langues : Anglais (eng) Mots-clés : Skeletal isomerization -- structure-performance  Butene Résumé : An experimental investigation of structure-performance effects in zeolite catalyzed skeletal isomerization has been carried out. Two structurally different, medium-pore-size zeolites (H-TON and H-FER) with similar acidities were compared in butene skeletal isomerization. While both catalysts proved to be efficient in the test reaction, their deactivation behavior differed substantially. H-FER exhibited significantly higher initial isobutene yields and selectivities, and the catalyst performance was also more stable with time-on-stream. H-TON, on the other hand, needed prolonged operation times in order to achieve product distributions comparable to those of H-FER. The predominant route to isobutene was found to be the monomolecular one, with the bimolecular paths of butene largely responsible for byproduct formation. H-TON was more selective toward disproportionation and, owing to its slightly larger pore dimensions, hydrogen transfer products. H-TON was also observed to be less sensitive to feed reactant than H-FER was, confirming previous theoretically calculated structure effects. Coke belonging to both aliphatic and aromatic families was detected over both zeolites, although the coke formed on H-FER was overall heavier and more aromatic in nature. The tested zeolites could be regenerated by burning of the carbonaceous deposits in air, and both catalysts regained almost all of their initial activities. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800061q [article] Skeletal isomerization of butene in fixed beds. 1. experimental investigation and structure-performance effects [texte imprimé] / Matias Kangas, Auteur ; Narendra Kumar, Auteur ; Elina Harlin, Auteur . - 2008 . - p. 5402–5412. Bibliogr. p. 5412 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5402–5412 Mots-clés : Skeletal isomerization -- structure-performance  Butene Résumé : An experimental investigation of structure-performance effects in zeolite catalyzed skeletal isomerization has been carried out. Two structurally different, medium-pore-size zeolites (H-TON and H-FER) with similar acidities were compared in butene skeletal isomerization. While both catalysts proved to be efficient in the test reaction, their deactivation behavior differed substantially. H-FER exhibited significantly higher initial isobutene yields and selectivities, and the catalyst performance was also more stable with time-on-stream. H-TON, on the other hand, needed prolonged operation times in order to achieve product distributions comparable to those of H-FER. The predominant route to isobutene was found to be the monomolecular one, with the bimolecular paths of butene largely responsible for byproduct formation. H-TON was more selective toward disproportionation and, owing to its slightly larger pore dimensions, hydrogen transfer products. H-TON was also observed to be less sensitive to feed reactant than H-FER was, confirming previous theoretically calculated structure effects. Coke belonging to both aliphatic and aromatic families was detected over both zeolites, although the coke formed on H-FER was overall heavier and more aromatic in nature. The tested zeolites could be regenerated by burning of the carbonaceous deposits in air, and both catalysts regained almost all of their initial activities. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800061q

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Skeletal isomerization of butene in fixed beds. part 2. kinetic and flow modeling / Matias Kangas in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5413–5426 Titre : Skeletal isomerization of butene in fixed beds. part 2. kinetic and flow modeling Type de document : texte imprimé Auteurs : Matias Kangas, Auteur ; Tapio Salmi, Auteur ; Dmitry Yu. Murzin, Auteur Année de publication : 2008 Article en page(s) : p. 5413–5426 Note générale : Bibliogr. p. 5325-5326 Langues : Anglais (eng) Mots-clés : Zeolite catalyzed hydrocarbon -- packed bed  Butene skeletal isomerization Résumé : Starting from detailed experimental studies of reaction kinetics, catalyst deactivation, and reactor flow conditions, mathematical models describing the dynamic reactor performance in zeolite catalyzed hydrocarbon transformations in packed beds have been developed. By using a sequential calculation procedure that involved changes in reactor models, solvers, and optimizers, kinetic parameters were regressed for two promising catalysts. Utilizing the estimated parameters and the developed kinetic and flow models, the skeletal isomerization of n-butene was accurately modeled. A proper description of adsorption and deactivation was shown to be as important as the kinetic formulation itself in obtaining good fits to the experimental results. Separable kinetics and deactivation functions were used. Relating the activity of the catalysts to the fraction of noncoked zeolite surface predicted the measured specific surface area to within 5-10%, indicating that reaction takes place throughout the whole catalyst pellet. Structure effects were observed in the estimated composite kinetic parameters. Protonated cyclopropane branching was much easier over H-FER, whereas n-butene codimerization with isobutene was significantly more facile over H-TON. Similar composite activation energies for the β-scission steps were obtained for both zeolites. The estimated reaction enthalpies for the oligomerization-cracking surface reaction were substantially lower than the thermodynamically calculated heats of reaction for the corresponding gas phase reactions, suggesting that olefin addition proceeds via the stepwise oligomerization mechanism. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800062m [article] Skeletal isomerization of butene in fixed beds. part 2. kinetic and flow modeling [texte imprimé] / Matias Kangas, Auteur ; Tapio Salmi, Auteur ; Dmitry Yu. Murzin, Auteur . - 2008 . - p. 5413–5426. Bibliogr. p. 5325-5326 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5413–5426 Mots-clés : Zeolite catalyzed hydrocarbon -- packed bed  Butene skeletal isomerization Résumé : Starting from detailed experimental studies of reaction kinetics, catalyst deactivation, and reactor flow conditions, mathematical models describing the dynamic reactor performance in zeolite catalyzed hydrocarbon transformations in packed beds have been developed. By using a sequential calculation procedure that involved changes in reactor models, solvers, and optimizers, kinetic parameters were regressed for two promising catalysts. Utilizing the estimated parameters and the developed kinetic and flow models, the skeletal isomerization of n-butene was accurately modeled. A proper description of adsorption and deactivation was shown to be as important as the kinetic formulation itself in obtaining good fits to the experimental results. Separable kinetics and deactivation functions were used. Relating the activity of the catalysts to the fraction of noncoked zeolite surface predicted the measured specific surface area to within 5-10%, indicating that reaction takes place throughout the whole catalyst pellet. Structure effects were observed in the estimated composite kinetic parameters. Protonated cyclopropane branching was much easier over H-FER, whereas n-butene codimerization with isobutene was significantly more facile over H-TON. Similar composite activation energies for the β-scission steps were obtained for both zeolites. The estimated reaction enthalpies for the oligomerization-cracking surface reaction were substantially lower than the thermodynamically calculated heats of reaction for the corresponding gas phase reactions, suggesting that olefin addition proceeds via the stepwise oligomerization mechanism. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800062m

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Effect of thermal activaton on the exchange behavior of aipo4 toward cu2+ ions / Syed Mustafa in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5427-5432 Titre : Effect of thermal activaton on the exchange behavior of aipo4 toward cu2+ ions Type de document : texte imprimé Auteurs : Syed Mustafa, Auteur ; Muhammad Javid, Auteur ; Muhammad Iqbal Zaman, Auteur Année de publication : 2008 Article en page(s) : p. 5427-5432 Note générale : Bibliogr. p. 5432 Langues : Anglais (eng) Mots-clés : Cu2+ ion adsorption  Titration studies  Freundlich equation Résumé : Cu2+ ion adsorption and potentiometric titration studies were carried out on AlPO4 as a function of pH, temperature, and activation. Two different samples thermally treated at 105 and 400 °C were employed for the sorption and potentiometric titration studies. The dissociation constant values (pKa) showed an increase with thermal activation, indicating a decrease in the surface acidity of AlPO4. Cu2+ ion adsorption was found to increase with pH, temperature, and thermal activation of the solid. The Freundlich equation was found to be applicable to the sorption data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070533h [article] Effect of thermal activaton on the exchange behavior of aipo4 toward cu2+ ions [texte imprimé] / Syed Mustafa, Auteur ; Muhammad Javid, Auteur ; Muhammad Iqbal Zaman, Auteur . - 2008 . - p. 5427-5432. Bibliogr. p. 5432 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5427-5432 Mots-clés : Cu2+ ion adsorption  Titration studies  Freundlich equation Résumé : Cu2+ ion adsorption and potentiometric titration studies were carried out on AlPO4 as a function of pH, temperature, and activation. Two different samples thermally treated at 105 and 400 °C were employed for the sorption and potentiometric titration studies. The dissociation constant values (pKa) showed an increase with thermal activation, indicating a decrease in the surface acidity of AlPO4. Cu2+ ion adsorption was found to increase with pH, temperature, and thermal activation of the solid. The Freundlich equation was found to be applicable to the sorption data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070533h

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Biosorption of commercial dyes on azadirachta indica leaf powder / Jyotirekha Sarma in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5433-5440 Titre : Biosorption of commercial dyes on azadirachta indica leaf powder : a case study with a basic dye rhodamine B Type de document : texte imprimé Auteurs : Jyotirekha Sarma, Auteur ; Arunima Sarma, Auteur ; G. Bhattacharyya, Auteur Année de publication : 2008 Article en page(s) : p. 5433-5440 Note générale : Bibliogr. p. 5440 Langues : Anglais (eng) Mots-clés : Biosorbents  Basic dye  Adsorption Résumé : Biosorbents, collected and prepared from nature, are most widely used for this purpose. In the present work, removal of a basic dye called Rhodamine B from aqueous solution by adsorption onto a biosorbent, Azadirachta indica (neem) leaf powder (AILP), was investigated. Removal was tested in a batch process with concentration of dye solution, AILP load, pH, temperature, and contact time as the working variables. The adsorption was favored by an acidic pH range and was best described by a second-order rate equation. The experimental data were verified by fitting into both Freundlich and Langmuir isotherms. Thermodynamically, the process was found to be exothermic accompanied by a decrease in entropy and increase in Gibbs energy as the temperature of adsorption was increased from 303 to 333 K. The effect of solution temperature, and the determination of the thermodynamic parameters of adsorption of Rhodamine B (RB) on AILP enthalpy of activation, entropy of activation, and free energy of activation, on the adsorption rates are important in understanding the adsorption mechanism. The rate and the transport/kinetic processes of dye adsorption onto the adsorbents are described by applying various kinetic adsorption models. This would lead to a better understanding of the mechanisms controlling the adsorption rate. The pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of RB onto AILP, suggesting that the adsorption mechanism might be a chemisorption process. The negative value of the enthalpy change suggested that the rise in the solution temperature did not favor RB adsorption onto AILP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071266i [article] Biosorption of commercial dyes on azadirachta indica leaf powder : a case study with a basic dye rhodamine B [texte imprimé] / Jyotirekha Sarma, Auteur ; Arunima Sarma, Auteur ; G. Bhattacharyya, Auteur . - 2008 . - p. 5433-5440. Bibliogr. p. 5440 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5433-5440 Mots-clés : Biosorbents  Basic dye  Adsorption Résumé : Biosorbents, collected and prepared from nature, are most widely used for this purpose. In the present work, removal of a basic dye called Rhodamine B from aqueous solution by adsorption onto a biosorbent, Azadirachta indica (neem) leaf powder (AILP), was investigated. Removal was tested in a batch process with concentration of dye solution, AILP load, pH, temperature, and contact time as the working variables. The adsorption was favored by an acidic pH range and was best described by a second-order rate equation. The experimental data were verified by fitting into both Freundlich and Langmuir isotherms. Thermodynamically, the process was found to be exothermic accompanied by a decrease in entropy and increase in Gibbs energy as the temperature of adsorption was increased from 303 to 333 K. The effect of solution temperature, and the determination of the thermodynamic parameters of adsorption of Rhodamine B (RB) on AILP enthalpy of activation, entropy of activation, and free energy of activation, on the adsorption rates are important in understanding the adsorption mechanism. The rate and the transport/kinetic processes of dye adsorption onto the adsorbents are described by applying various kinetic adsorption models. This would lead to a better understanding of the mechanisms controlling the adsorption rate. The pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of RB onto AILP, suggesting that the adsorption mechanism might be a chemisorption process. The negative value of the enthalpy change suggested that the rise in the solution temperature did not favor RB adsorption onto AILP. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071266i

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Cobalt, nickel, and copper ion-exchanged on heterocyclic amine-intercalated titanium hydrogenphosphate compounds / Liliane M Nunes in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5441-5446 Titre : Cobalt, nickel, and copper ion-exchanged on heterocyclic amine-intercalated titanium hydrogenphosphate compounds Type de document : texte imprimé Auteurs : Liliane M Nunes, Auteur ; Bruno Parente, Auteur ; Maria A. M. Maurera, Auteur Année de publication : 2008 Article en page(s) : p. 5441-5446 Note générale : Bibliogr. p. 5445-5446 Langues : Anglais (eng) Mots-clés : Cobalt  Nickel  Copper  Ion exchange  X-ray diffraction Résumé : Crystalline α-titanium hydrogenphosphate with a maximum theoretical ion-exchange capacity of 7.60 mmol g−1 had aromatic organic 3- and 4-aminopyridine molecules inserted into the free lamellar space at 2.32 and 3.14 mmol g−1. This expands the interlamellar distance from 760 to 1193 and 1261 pm, respectively. The effectiveness of these new matrices for exchanging cations at the solid/liquid interface depends on the intercalated monoprotonated amines and gives cation-exchange order Cu2+ > Co2+ > Ni2+, not only from individual cationic solutions, but also when an equimolar mixture of these cations is employed. For the first procedure, copper had the most exchange ability giving 2.42 and 2.26 mmol g−1. From the cation mixture, it presented ion-exchange capacities (1.91 and 1.80 mmol g−1), that are nearly four times that obtained for cobalt (0.560 and 0.384 mmol g−1). No significant values were obtained for nickel (0.084 and 0.039 mmol g−1) when present in the mixture. The X-ray diffraction patterns for copper-containing materials showed a reasonable increase of disorganization as the ion-exchange progressed, to change the original crystalline structure to an amorphous form. Carbon and nitrogen elemental analyses demonstrated a decrease in the amount of amine after the ion-exchange process, when compared to the respective precursors, reflecting successive displacement of the inserted organic molecule in the inorganic matrix. The favorable exchanging mechanism reaction seems to be associated with the diffusion of the cations inside the intercalated lamellar compounds. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716114 [article] Cobalt, nickel, and copper ion-exchanged on heterocyclic amine-intercalated titanium hydrogenphosphate compounds [texte imprimé] / Liliane M Nunes, Auteur ; Bruno Parente, Auteur ; Maria A. M. Maurera, Auteur . - 2008 . - p. 5441-5446. Bibliogr. p. 5445-5446 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5441-5446 Mots-clés : Cobalt  Nickel  Copper  Ion exchange  X-ray diffraction Résumé : Crystalline α-titanium hydrogenphosphate with a maximum theoretical ion-exchange capacity of 7.60 mmol g−1 had aromatic organic 3- and 4-aminopyridine molecules inserted into the free lamellar space at 2.32 and 3.14 mmol g−1. This expands the interlamellar distance from 760 to 1193 and 1261 pm, respectively. The effectiveness of these new matrices for exchanging cations at the solid/liquid interface depends on the intercalated monoprotonated amines and gives cation-exchange order Cu2+ > Co2+ > Ni2+, not only from individual cationic solutions, but also when an equimolar mixture of these cations is employed. For the first procedure, copper had the most exchange ability giving 2.42 and 2.26 mmol g−1. From the cation mixture, it presented ion-exchange capacities (1.91 and 1.80 mmol g−1), that are nearly four times that obtained for cobalt (0.560 and 0.384 mmol g−1). No significant values were obtained for nickel (0.084 and 0.039 mmol g−1) when present in the mixture. The X-ray diffraction patterns for copper-containing materials showed a reasonable increase of disorganization as the ion-exchange progressed, to change the original crystalline structure to an amorphous form. Carbon and nitrogen elemental analyses demonstrated a decrease in the amount of amine after the ion-exchange process, when compared to the respective precursors, reflecting successive displacement of the inserted organic molecule in the inorganic matrix. The favorable exchanging mechanism reaction seems to be associated with the diffusion of the cations inside the intercalated lamellar compounds. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716114

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Determination of diffusion coefficients and interface mass-transfer coefficients of the crude oil-CO2 system by analysis of the dynamic and equilibrium interfacial tensions / Daoyong Yang in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5447–5455 Titre : Determination of diffusion coefficients and interface mass-transfer coefficients of the crude oil-CO2 system by analysis of the dynamic and equilibrium interfacial tensions Type de document : texte imprimé Auteurs : Daoyong Yang, Auteur ; Yongan Gu, Auteur Année de publication : 2008 Article en page(s) : p. 5447–5455 Note générale : Bibliogr. p. 5454-5455 Langues : Anglais (eng) Mots-clés : Diffusion coefficients  Mass-transfer Crude oil−  CO2 system Résumé : In this paper, a newly developed dynamic interfacial tension method has been applied to simultaneously determine the diffusion coefficients and interface mass-transfer coefficients of the crude oil−CO2 system at high pressures and a constant temperature. Experimentally, the dynamic and equilibrium interfacial tensions of the crude oil−CO2 system are measured by using the axisymmetric drop shape analysis (ADSA) technique for the pendant drop case. Theoretically, a mathematical model is formulated to obtain the time-dependent CO2 concentration distribution inside the pendant oil drop. Then, in terms of a predetermined calibration curve of the measured equilibrium interfacial tension versus the calculated equilibrium CO2 concentration in the crude oil, the dynamic interfacial tension at any time is calculated. Subsequently, an objective function is constructed to express the overall discrepancy between the numerically calculated and the experimentally measured dynamic interfacial tensions at different times. The CO2 diffusion coefficient and the mass-transfer Biot number are used as adjustable parameters and thus determined once the global minimum objective function is achieved. The diffusion coefficient, the mass-transfer Biot number, and the interface mass-transfer coefficient of CO2 mass transfer in a medium crude oil sample at P = 0.1−5.0 MPa and T = 27 °C are found to be 0.47−2.49 × 10−9 m2/s, 2.3−6.8, 0.88−8.41 × 10-5 m/s, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800053d [article] Determination of diffusion coefficients and interface mass-transfer coefficients of the crude oil-CO2 system by analysis of the dynamic and equilibrium interfacial tensions [texte imprimé] / Daoyong Yang, Auteur ; Yongan Gu, Auteur . - 2008 . - p. 5447–5455. Bibliogr. p. 5454-5455 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5447–5455 Mots-clés : Diffusion coefficients  Mass-transfer Crude oil−  CO2 system Résumé : In this paper, a newly developed dynamic interfacial tension method has been applied to simultaneously determine the diffusion coefficients and interface mass-transfer coefficients of the crude oil−CO2 system at high pressures and a constant temperature. Experimentally, the dynamic and equilibrium interfacial tensions of the crude oil−CO2 system are measured by using the axisymmetric drop shape analysis (ADSA) technique for the pendant drop case. Theoretically, a mathematical model is formulated to obtain the time-dependent CO2 concentration distribution inside the pendant oil drop. Then, in terms of a predetermined calibration curve of the measured equilibrium interfacial tension versus the calculated equilibrium CO2 concentration in the crude oil, the dynamic interfacial tension at any time is calculated. Subsequently, an objective function is constructed to express the overall discrepancy between the numerically calculated and the experimentally measured dynamic interfacial tensions at different times. The CO2 diffusion coefficient and the mass-transfer Biot number are used as adjustable parameters and thus determined once the global minimum objective function is achieved. The diffusion coefficient, the mass-transfer Biot number, and the interface mass-transfer coefficient of CO2 mass transfer in a medium crude oil sample at P = 0.1−5.0 MPa and T = 27 °C are found to be 0.47−2.49 × 10−9 m2/s, 2.3−6.8, 0.88−8.41 × 10-5 m/s, respectively. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800053d

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Correlation of cement performance property measurements with C3S/C2S ratio determined by solid state 29Si NMR measurements / Christopher L. Edwards in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5456–5463 Titre : Correlation of cement performance property measurements with C3S/C2S ratio determined by solid state 29Si NMR measurements Type de document : texte imprimé Auteurs : Christopher L. Edwards, Auteur ; Rickey Morgan, Auteur ; Lewis Norman, Auteur ; Gary P. Funkhouser, Auteur Année de publication : 2008 Article en page(s) : p. 5456–5463 Note générale : Bibliogr. p. 5463 Langues : Anglais (eng) Mots-clés : API -- physicochemical properties  engineering performance Nuclear magnetic resonance measurement Résumé : The physicochemical and engineering performance properties of several API class G and H ordinary Portland cements (OPCs) from various foreign and domestic sources have been investigated in comparison with the tricalcium silicate/dicalcium silicate ratio (C3S/C2S) as determined by magic angle spinning (MAS) 29Si nuclear magnetic resonance (NMR) experiments. XRF-derived oxide analysis appears to provide a lower C3S/C2S ratio than determined by NMR analysis. Furthermore, oxide analysis suggests that all the cements have a C3S/C2S ratio of 2−5, while our NMR method suggests the actual range is significantly broader. Determination of C3S/C2S ratios by NMR provides an effective method of analysis for cements, owing to NMR’s direct measurement of the minerals in question. NMR C3S/C2S ratios demonstrate predictive ability for the determination of engineering performance properties. This is especially the case for prediction of strength development; in keeping with generally accepted understanding of cement hydration behavior, the strength development correlates with increasing C3S/C2S ratio, i.e., C3S content. The observed correlation between NMR-derived silicate ratio and strength development holds for cements in the presence of either a retarder (lignosulfonate) or a fluid loss additive (N,N-dimethylformamide/2-acrylamido-2-methylpropanesulfonic acid copolymer). No significant correlation is observed between C3S/C2S ratio and the 72 h crush strength. The lack of dependency of either thickening time or Young’s modulus to the C3S/C2S ratio as determined by MAS 29Si NMR measurements suggests that these physical properties are independent of the relative silicate composition. No correlations are observed between any physical property and the silicate ratio derived from XRF data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000925 [article] Correlation of cement performance property measurements with C3S/C2S ratio determined by solid state 29Si NMR measurements [texte imprimé] / Christopher L. Edwards, Auteur ; Rickey Morgan, Auteur ; Lewis Norman, Auteur ; Gary P. Funkhouser, Auteur . - 2008 . - p. 5456–5463. Bibliogr. p. 5463 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5456–5463 Mots-clés : API -- physicochemical properties  engineering performance Nuclear magnetic resonance measurement Résumé : The physicochemical and engineering performance properties of several API class G and H ordinary Portland cements (OPCs) from various foreign and domestic sources have been investigated in comparison with the tricalcium silicate/dicalcium silicate ratio (C3S/C2S) as determined by magic angle spinning (MAS) 29Si nuclear magnetic resonance (NMR) experiments. XRF-derived oxide analysis appears to provide a lower C3S/C2S ratio than determined by NMR analysis. Furthermore, oxide analysis suggests that all the cements have a C3S/C2S ratio of 2−5, while our NMR method suggests the actual range is significantly broader. Determination of C3S/C2S ratios by NMR provides an effective method of analysis for cements, owing to NMR’s direct measurement of the minerals in question. NMR C3S/C2S ratios demonstrate predictive ability for the determination of engineering performance properties. This is especially the case for prediction of strength development; in keeping with generally accepted understanding of cement hydration behavior, the strength development correlates with increasing C3S/C2S ratio, i.e., C3S content. The observed correlation between NMR-derived silicate ratio and strength development holds for cements in the presence of either a retarder (lignosulfonate) or a fluid loss additive (N,N-dimethylformamide/2-acrylamido-2-methylpropanesulfonic acid copolymer). No significant correlation is observed between C3S/C2S ratio and the 72 h crush strength. The lack of dependency of either thickening time or Young’s modulus to the C3S/C2S ratio as determined by MAS 29Si NMR measurements suggests that these physical properties are independent of the relative silicate composition. No correlations are observed between any physical property and the silicate ratio derived from XRF data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8000925

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Improvements in fault tolerance characteristics for large chemical plants: 1. waste water treatment plant with decentralized control / Zumoffen, David in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5664-5481 Titre : Improvements in fault tolerance characteristics for large chemical plants: 1. waste water treatment plant with decentralized control Type de document : texte imprimé Auteurs : Zumoffen, David, Auteur ; Basualdo, Marta, Auteur Année de publication : 2008 Article en page(s) : p. 5664-5481 Note générale : Bibliogr. p. 5481 Langues : Anglais (eng) Mots-clés : Waste Water Treatment Plant  FDIE systems  Fault-tolerant scheme Résumé : A decentralized control scheme integrated with a recently developed fault detection, isolation, and estimation (FDIE) system applied on a benchmark of wastewater treatment plant (WWTP) is discussed here. This work belongs to a series whose objective is to demonstrate quantitatively the achievable improvements on the fault-tolerance characteristics supported by the integration with FDIE systems. In the previous work, a decentralized structure applied on a larger benchmark (such as the pulp mill plant) was presented. Specific aspects that are related to that case study were successfully handled by this methodology. Here, the WWTP presents new scenarios based on the occurrence of faults and their incidence on the associated dynamic with this process. In this work, faults such as extra dead time at actuators and bias and slow drifts in sensors (which, in some cases, can cause saturation), are analyzed. Under these conditions, a real need exists for turning the existent control scheme into a fault-tolerant (FT) scheme. This is done through reconfiguration of the controllers, using online identification and model-based control (MBC) tools. As the main contribution of this paper, a rigorous quantitative analysis is performed that takes account of a complete set of simulation cases, showing different scenarios. The accurate comparison study is given through several indexes associated with the WWTP benchmark, and others that are useful for analyzing the methodology are proposed here. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800098t [article] Improvements in fault tolerance characteristics for large chemical plants: 1. waste water treatment plant with decentralized control [texte imprimé] / Zumoffen, David, Auteur ; Basualdo, Marta, Auteur . - 2008 . - p. 5664-5481. Bibliogr. p. 5481 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5664-5481 Mots-clés : Waste Water Treatment Plant  FDIE systems  Fault-tolerant scheme Résumé : A decentralized control scheme integrated with a recently developed fault detection, isolation, and estimation (FDIE) system applied on a benchmark of wastewater treatment plant (WWTP) is discussed here. This work belongs to a series whose objective is to demonstrate quantitatively the achievable improvements on the fault-tolerance characteristics supported by the integration with FDIE systems. In the previous work, a decentralized structure applied on a larger benchmark (such as the pulp mill plant) was presented. Specific aspects that are related to that case study were successfully handled by this methodology. Here, the WWTP presents new scenarios based on the occurrence of faults and their incidence on the associated dynamic with this process. In this work, faults such as extra dead time at actuators and bias and slow drifts in sensors (which, in some cases, can cause saturation), are analyzed. Under these conditions, a real need exists for turning the existent control scheme into a fault-tolerant (FT) scheme. This is done through reconfiguration of the controllers, using online identification and model-based control (MBC) tools. As the main contribution of this paper, a rigorous quantitative analysis is performed that takes account of a complete set of simulation cases, showing different scenarios. The accurate comparison study is given through several indexes associated with the WWTP benchmark, and others that are useful for analyzing the methodology are proposed here. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800098t

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Improvements in fault tolerance characteristics for large chemical plants: 2. pulp mill process with model predictive control / Zumoffen, David in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5482–5500 Titre : Improvements in fault tolerance characteristics for large chemical plants: 2. pulp mill process with model predictive control Type de document : texte imprimé Auteurs : Zumoffen, David, Auteur ; Basualdo, Marta, Auteur ; Gonzalo Molina, Auteur Année de publication : 2008 Article en page(s) : p. 5482–5500 Note générale : Bibliogr. p. 5499-5500 Langues : Anglais (eng) Mots-clés : Large chemical plants  Wastewater treatment plant  FDIE system  Model predictive control Résumé : A model predictive control (MPC) scheme integrated with a recently developed fault detection, isolation, and estimation (FDIE) system applied on a pulp mill (PM) process is discussed. This work belongs to a series whose objective is to achieve improvements on the fault tolerance characteristics for conventional and advanced control schemes. In two previous works, different decentralized control structures were integrated with the same FDIE system. It was tested for large chemical plants, such as PM and wastewater treatment plant (WWTP) processes. Each one offered different dynamics and fault scenarios, because of the specific impact produced by the abnormal events considered. For doing rigorous comparisons, the PM process is the same as that studied in one of the previous works. Although the FDIE system presents the same general structure, it must be redesigned, because of the inherent fault-tolerant characteristics of the classical MPC. In this context, it is more difficult to determine the patterns associated with each fault. A complete set of simulation results, evaluated by the same indexes used in the previous work, together with a cost analysis about the process operational profits, is included. The comparisons are done with and without the FDIE system, alternative control solutions providing from the decentralized and MPC structures are evaluated. The case where the link with the FDIE system is done is indicated as fault-tolerant MPC (FTMPC). As new results, a rigorous quantitative analysis to answer the question about which is the real improvement that can be introduced by the FTMPC is made, accounting for very complex scenarios. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800100r [article] Improvements in fault tolerance characteristics for large chemical plants: 2. pulp mill process with model predictive control [texte imprimé] / Zumoffen, David, Auteur ; Basualdo, Marta, Auteur ; Gonzalo Molina, Auteur . - 2008 . - p. 5482–5500. Bibliogr. p. 5499-5500 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5482–5500 Mots-clés : Large chemical plants  Wastewater treatment plant  FDIE system  Model predictive control Résumé : A model predictive control (MPC) scheme integrated with a recently developed fault detection, isolation, and estimation (FDIE) system applied on a pulp mill (PM) process is discussed. This work belongs to a series whose objective is to achieve improvements on the fault tolerance characteristics for conventional and advanced control schemes. In two previous works, different decentralized control structures were integrated with the same FDIE system. It was tested for large chemical plants, such as PM and wastewater treatment plant (WWTP) processes. Each one offered different dynamics and fault scenarios, because of the specific impact produced by the abnormal events considered. For doing rigorous comparisons, the PM process is the same as that studied in one of the previous works. Although the FDIE system presents the same general structure, it must be redesigned, because of the inherent fault-tolerant characteristics of the classical MPC. In this context, it is more difficult to determine the patterns associated with each fault. A complete set of simulation results, evaluated by the same indexes used in the previous work, together with a cost analysis about the process operational profits, is included. The comparisons are done with and without the FDIE system, alternative control solutions providing from the decentralized and MPC structures are evaluated. The case where the link with the FDIE system is done is indicated as fault-tolerant MPC (FTMPC). As new results, a rigorous quantitative analysis to answer the question about which is the real improvement that can be introduced by the FTMPC is made, accounting for very complex scenarios. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800100r

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Midterm supply chain planning under uncertainty / Kishalay Mitra in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5501–5511 Titre : Midterm supply chain planning under uncertainty : a multiobjective chance constrained programming framework Type de document : texte imprimé Auteurs : Kishalay Mitra, Auteur ; Ravindra D. Gudi, Auteur ; Sachin C. Patwardhan, Auteur ; Gautam Sardar, Auteur Année de publication : 2008 Article en page(s) : p. 5501–5511 Note générale : Bibliogr. p. 5510-5511 Langues : Anglais (eng) Mots-clés : Chain planning  Chance constrained programming approach Résumé : Uncertainty issues associated with a multisite, multiproduct supply chain planning problem has been analyzed in this paper, using the chance constrained programming (CCP) approach. In the literature, such problems have been addressed using the scenario-based two-stage stochastic programming approach. Although this approach has merits, in terms of decomposition, the computational complexity, even for small-size planning problems, is generally quite large, leading to either huge time consumption in solving the problem or an inability to solve big instances of problems under a standard solver environment. To make the aforementioned lacunea of two-stage stochastic programming more tractable, the problems under uncertainty have been recast in this paper in a CCP framework that uses a more suitable representation of uncertainty. Addressing uncertainty issues in product demands and machine uptime, using the CCP approach, leads to the evaluation of multiobjective tradeoffs that are analyzed here in the Pareto sense, and the ε-constraint approach is used to generate those Pareto optimal (PO) points. Different aspects of uncertainty issues are analyzed in detail by taking a few PO points among the total set of PO solutions found for this problem. It is seen that this CCP-based approach is quite generic, relatively simple to use and can be adapted for bigger size planning problems, as the equivalent deterministic problem does not blow up in size with the CCP approach. We demonstrate the analysis on a relatively moderate size midterm planning problem taken from published work [McDonald, C. M.; Karimi, I. A. Ind. Eng. Chem. Res. 1997, 36, 2691] and discuss various aspects of uncertainty in the context of this problem. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710364 [article] Midterm supply chain planning under uncertainty : a multiobjective chance constrained programming framework [texte imprimé] / Kishalay Mitra, Auteur ; Ravindra D. Gudi, Auteur ; Sachin C. Patwardhan, Auteur ; Gautam Sardar, Auteur . - 2008 . - p. 5501–5511. Bibliogr. p. 5510-5511 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5501–5511 Mots-clés : Chain planning  Chance constrained programming approach Résumé : Uncertainty issues associated with a multisite, multiproduct supply chain planning problem has been analyzed in this paper, using the chance constrained programming (CCP) approach. In the literature, such problems have been addressed using the scenario-based two-stage stochastic programming approach. Although this approach has merits, in terms of decomposition, the computational complexity, even for small-size planning problems, is generally quite large, leading to either huge time consumption in solving the problem or an inability to solve big instances of problems under a standard solver environment. To make the aforementioned lacunea of two-stage stochastic programming more tractable, the problems under uncertainty have been recast in this paper in a CCP framework that uses a more suitable representation of uncertainty. Addressing uncertainty issues in product demands and machine uptime, using the CCP approach, leads to the evaluation of multiobjective tradeoffs that are analyzed here in the Pareto sense, and the ε-constraint approach is used to generate those Pareto optimal (PO) points. Different aspects of uncertainty issues are analyzed in detail by taking a few PO points among the total set of PO solutions found for this problem. It is seen that this CCP-based approach is quite generic, relatively simple to use and can be adapted for bigger size planning problems, as the equivalent deterministic problem does not blow up in size with the CCP approach. We demonstrate the analysis on a relatively moderate size midterm planning problem taken from published work [McDonald, C. M.; Karimi, I. A. Ind. Eng. Chem. Res. 1997, 36, 2691] and discuss various aspects of uncertainty in the context of this problem. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0710364

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Simultaneous retrofit and heat integration of chemical processes / José M. Ponce-Ortega in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5512–5528 Titre : Simultaneous retrofit and heat integration of chemical processes Type de document : texte imprimé Auteurs : José M. Ponce-Ortega, Auteur ; Arturo Jimenez-Gutierrez, Auteur ; Ignacio E. Grossmann, Auteur Année de publication : 2008 Article en page(s) : p. 5512–5528 Note générale : Bibliogr. p. 5528 Langues : Anglais (eng) Mots-clés : Heat exchanger networks -- retrofit  Mixed-integer nonlinear programming model Résumé : In this paper, a new formulation for the retrofit of heat exchanger networks considering process modifications is presented. The method accounts for the interactions between the process conditions and the heat integration options to provide an optimal structure for a redesigned heat exchanger network. The formulation is based on a superstructure that considers explicitly the plant layout and the piping arrangement, which yields a mixed-integer nonlinear programming model. The model presented here includes the treatment of isothermal process streams that exchange their latent heats, in addition to the streams commonly considered with sensible heat loads. The objective function consists of maximizing the total annual profit for the retrofit process, which includes the income from products sales and the expenses due to raw materials, capital cost for new units, utility costs, and the piping modification costs. The results for the cases of study show that significant improvement in the process profitability can be obtained with the simultaneous approach presented in this work for process retrofit with respect to the sole consideration of the heat exchanger networks. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071182%2B [article] Simultaneous retrofit and heat integration of chemical processes [texte imprimé] / José M. Ponce-Ortega, Auteur ; Arturo Jimenez-Gutierrez, Auteur ; Ignacio E. Grossmann, Auteur . - 2008 . - p. 5512–5528. Bibliogr. p. 5528 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5512–5528 Mots-clés : Heat exchanger networks -- retrofit  Mixed-integer nonlinear programming model Résumé : In this paper, a new formulation for the retrofit of heat exchanger networks considering process modifications is presented. The method accounts for the interactions between the process conditions and the heat integration options to provide an optimal structure for a redesigned heat exchanger network. The formulation is based on a superstructure that considers explicitly the plant layout and the piping arrangement, which yields a mixed-integer nonlinear programming model. The model presented here includes the treatment of isothermal process streams that exchange their latent heats, in addition to the streams commonly considered with sensible heat loads. The objective function consists of maximizing the total annual profit for the retrofit process, which includes the income from products sales and the expenses due to raw materials, capital cost for new units, utility costs, and the piping modification costs. The results for the cases of study show that significant improvement in the process profitability can be obtained with the simultaneous approach presented in this work for process retrofit with respect to the sole consideration of the heat exchanger networks. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071182%2B

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Design of nonlinear sensor networks for process plants / DuyQuang Nguyen in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5529-5542 Titre : Design of nonlinear sensor networks for process plants Type de document : texte imprimé Auteurs : DuyQuang Nguyen, Auteur ; Miguel J. Bagajewicz, Auteur Année de publication : 2008 Article en page(s) : p. 5529-5542 Note générale : Bibliogr. p.5541-5542 Langues : Anglais (eng) Mots-clés : Nonlinear sensor networks  problem Résumé : In this article we extend and generalize the ideas of two previous articles devoted to linear sensor networks to nonlinear systems. In those previous articles the use of cutsets and a decomposition procedure were proposed and proved efficient to solve large scale linear problems. In this article we show that a similar procedure, now based on a variable elimination scheme, can be also used efficiently for medium size nonlinear problems, but its computational efficiency for realistic large scale problems is not satisfactory. We also propose an alternative technique for the case of tree enumeration using instruments instead of equations that is very efficient for heavily instrumented flowsheets. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0708778 [article] Design of nonlinear sensor networks for process plants [texte imprimé] / DuyQuang Nguyen, Auteur ; Miguel J. Bagajewicz, Auteur . - 2008 . - p. 5529-5542. Bibliogr. p.5541-5542 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5529-5542 Mots-clés : Nonlinear sensor networks  problem Résumé : In this article we extend and generalize the ideas of two previous articles devoted to linear sensor networks to nonlinear systems. In those previous articles the use of cutsets and a decomposition procedure were proposed and proved efficient to solve large scale linear problems. In this article we show that a similar procedure, now based on a variable elimination scheme, can be also used efficiently for medium size nonlinear problems, but its computational efficiency for realistic large scale problems is not satisfactory. We also propose an alternative technique for the case of tree enumeration using instruments instead of equations that is very efficient for heavily instrumented flowsheets. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0708778

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A simultaneous optimization approach to generate design specifications and maintenance policies for the multilayer protective systems in chemical processes / Kuo-Hwa Liang in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5543–5555 Titre : A simultaneous optimization approach to generate design specifications and maintenance policies for the multilayer protective systems in chemical processes Type de document : texte imprimé Auteurs : Kuo-Hwa Liang, Auteur ; Chuei-Tin Chang, Auteur Année de publication : 2008 Article en page(s) : p. 5543–5555 Note générale : Bibliogr. p. 5555 Langues : Anglais (eng) Mots-clés : Protective system  Subsystem  Chemical processes Résumé : Generally speaking, a protective system is adopted to perform two basic functions, i.e., alarm and shutdown. The subsystem to perform the former function is equipped with one or more independent sensors. On the basis of the online measurements of these sensors, Boolean logic is applied to determine whether or not alarm signal(s) should be issued. The subsystem for the latter task is usually configured with solenoid valves. In response to the aforementioned signal(s), these valves are energized (or de-energized) to carry out the required shutdown operation. Since the hardware failures are basically random events, the reliability (or availability) of a protective system is highly dependent upon its structural characteristics and also maintenance policies. Traditionally, the alarm logic and shutdown configuration are synthesized according to experience and the maintenance scheme is also established on an ad hoc basis. The aim of this study is to develop an integrated mathematical programming model to minimize the total expected expenditure, i.e., the sum of the capital investments, the expected maintenance costs, and the expected losses due to system failures. From the optimal solution, one should be able to produce the design specifications for every protection layer, i.e., (1) the number of sensors and the corresponding alarm logic, (2) the number of valves and the corresponding shutdown configuration, and (3) the needed repair/replacement policies. In this work, the sensors and valves are assumed to be maintained respectively with the corrective and preventive strategies. Thus, the optimal number of spare sensors stored offline and the best inspection interval for each valve can also be determined by solving this model. Extensive case studies have been carried out to demonstrate the feasibility and effectiveness of the proposed approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071188z [article] A simultaneous optimization approach to generate design specifications and maintenance policies for the multilayer protective systems in chemical processes [texte imprimé] / Kuo-Hwa Liang, Auteur ; Chuei-Tin Chang, Auteur . - 2008 . - p. 5543–5555. Bibliogr. p. 5555 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5543–5555 Mots-clés : Protective system  Subsystem  Chemical processes Résumé : Generally speaking, a protective system is adopted to perform two basic functions, i.e., alarm and shutdown. The subsystem to perform the former function is equipped with one or more independent sensors. On the basis of the online measurements of these sensors, Boolean logic is applied to determine whether or not alarm signal(s) should be issued. The subsystem for the latter task is usually configured with solenoid valves. In response to the aforementioned signal(s), these valves are energized (or de-energized) to carry out the required shutdown operation. Since the hardware failures are basically random events, the reliability (or availability) of a protective system is highly dependent upon its structural characteristics and also maintenance policies. Traditionally, the alarm logic and shutdown configuration are synthesized according to experience and the maintenance scheme is also established on an ad hoc basis. The aim of this study is to develop an integrated mathematical programming model to minimize the total expected expenditure, i.e., the sum of the capital investments, the expected maintenance costs, and the expected losses due to system failures. From the optimal solution, one should be able to produce the design specifications for every protection layer, i.e., (1) the number of sensors and the corresponding alarm logic, (2) the number of valves and the corresponding shutdown configuration, and (3) the needed repair/replacement policies. In this work, the sensors and valves are assumed to be maintained respectively with the corrective and preventive strategies. Thus, the optimal number of spare sensors stored offline and the best inspection interval for each valve can also be determined by solving this model. Extensive case studies have been carried out to demonstrate the feasibility and effectiveness of the proposed approach. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071188z

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Synergy in mergers of petrochemical companies within a complex considering purchasing and selling advantage with process integration / Sung-Geun Yoon in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5556–5567 Titre : Synergy in mergers of petrochemical companies within a complex considering purchasing and selling advantage with process integration Type de document : texte imprimé Auteurs : Sung-Geun Yoon, Auteur ; Seung Bin Park, Auteur ; Sunwon Park, Auteur ; Jeongseok Lee, Auteur Année de publication : 2008 Article en page(s) : p. 5556–5567 Note générale : Bibliogr. p. 5566-5567 Langues : Anglais (eng) Mots-clés : Mergers -- petrochemical companies  Process integration Résumé : Mergers and Acquisitions, M&A, have been active in the petrochemical industry. However, the synergy created by the merger of petrochemical companies has rarely been studied, although it is the primary goal of a merger. This study deals with the merger of petrochemical companies located within one complex. Synergy considerations resulting from process network and boiler integration with fixed cost reduction and market power increase in upstream market (i.e., resource purchasing advantage) and downstream market (i.e., product selling advantage) are included. A novel mathematical model is formulated that represents the operation of a process network aiming at increasing the profitability of merged companies. The resource purchasing advantage and product selling advantage options are considered by means of various scenarios. The proposed model is applied to Korean Naphtha Cracking Center, NCC, companies in one complex. The results, presented in three case studies, demonstrate that a merger creates synergy primarily from the purchasing advantage and selling advantage options, while the process network and boiler integration which simply collects various processes can create a little synergy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071447k [article] Synergy in mergers of petrochemical companies within a complex considering purchasing and selling advantage with process integration [texte imprimé] / Sung-Geun Yoon, Auteur ; Seung Bin Park, Auteur ; Sunwon Park, Auteur ; Jeongseok Lee, Auteur . - 2008 . - p. 5556–5567. Bibliogr. p. 5566-5567 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5556–5567 Mots-clés : Mergers -- petrochemical companies  Process integration Résumé : Mergers and Acquisitions, M&A, have been active in the petrochemical industry. However, the synergy created by the merger of petrochemical companies has rarely been studied, although it is the primary goal of a merger. This study deals with the merger of petrochemical companies located within one complex. Synergy considerations resulting from process network and boiler integration with fixed cost reduction and market power increase in upstream market (i.e., resource purchasing advantage) and downstream market (i.e., product selling advantage) are included. A novel mathematical model is formulated that represents the operation of a process network aiming at increasing the profitability of merged companies. The resource purchasing advantage and product selling advantage options are considered by means of various scenarios. The proposed model is applied to Korean Naphtha Cracking Center, NCC, companies in one complex. The results, presented in three case studies, demonstrate that a merger creates synergy primarily from the purchasing advantage and selling advantage options, while the process network and boiler integration which simply collects various processes can create a little synergy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071447k

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E-waste management via liquid emulsion membrane (LEM) process / Mangesh S. Talekar in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5568–5575 Titre : E-waste management via liquid emulsion membrane (LEM) process : enrichment of Cd(II) from lean solution Type de document : texte imprimé Auteurs : Mangesh S. Talekar, Auteur ; Vijaykumar. V. Mahajani, Auteur Année de publication : 2008 Article en page(s) : p. 5568–5575 Note générale : Bibliogr. p. 5575 Langues : Anglais (eng) Mots-clés : E-waste management  Liquid emulsion membrane process  Cadmium(II)  Liquid-liquid extraction studies Résumé : E-waste management via liquid emulsion membrane (LEM) process for the extraction and enrichment of cadmium(II) has been studied using di-2-ethylhexyl phosphoric acid (D2EHPA) dissolved in n-dodecane as carrier and methane sulfonic acid (MSA) as a strip phase. The complexation stoichiometric coefficient (n) and equilibrium constant (Kex) were determined by carrying out conventional liquid-liquid extraction studies. The factorial design method was used to see the importance of parameters. Emulsion preparation parameters such as carrier concentration, surfactant concentration, and internal strip phase (MSA) concentration were determined to get maximum extraction and enrichment. The influence of operating process parameters on the performance of LEM process, i.e., residence time, speed of agitation, and treat ratio, has been studied. A realistic simple model to aid the process design of LEM process has been developed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0705711 [article] E-waste management via liquid emulsion membrane (LEM) process : enrichment of Cd(II) from lean solution [texte imprimé] / Mangesh S. Talekar, Auteur ; Vijaykumar. V. Mahajani, Auteur . - 2008 . - p. 5568–5575. Bibliogr. p. 5575 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5568–5575 Mots-clés : E-waste management  Liquid emulsion membrane process  Cadmium(II)  Liquid-liquid extraction studies Résumé : E-waste management via liquid emulsion membrane (LEM) process for the extraction and enrichment of cadmium(II) has been studied using di-2-ethylhexyl phosphoric acid (D2EHPA) dissolved in n-dodecane as carrier and methane sulfonic acid (MSA) as a strip phase. The complexation stoichiometric coefficient (n) and equilibrium constant (Kex) were determined by carrying out conventional liquid-liquid extraction studies. The factorial design method was used to see the importance of parameters. Emulsion preparation parameters such as carrier concentration, surfactant concentration, and internal strip phase (MSA) concentration were determined to get maximum extraction and enrichment. The influence of operating process parameters on the performance of LEM process, i.e., residence time, speed of agitation, and treat ratio, has been studied. A realistic simple model to aid the process design of LEM process has been developed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0705711

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Online estimation and monitoring of diastereomeric resolution using FBRM, ATR-FTIR, and raman spectroscopy / Sze-Wing Wong in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5576–5584 Titre : Online estimation and monitoring of diastereomeric resolution using FBRM, ATR-FTIR, and raman spectroscopy Type de document : texte imprimé Auteurs : Sze-Wing Wong, Auteur ; Christos Georgakis, Auteur ; Gregory D. Botsaris, Auteur Année de publication : 2008 Article en page(s) : p. 5576–5584 Note générale : Bibliogr. p. 5583-5584 Langues : Anglais (eng) Mots-clés : Diastereomers -- fractional solid composition  Raman spectroscopy Résumé : This paper first demonstrates that the estimation of fractional solid composition of two diastereomers is possible by incorporating Raman spectra, slurry density, and temperature into a partial least squares (PLS) model. Since slurry density measurement is not readily available, the online estimation is obtained through another PLS model that utilizes online Raman spectroscopy, focus beam reflectance measurement (FBRM), attenuated total reflection Fourier transform infrared (ATR-FTIR), and/or additional process information such as temperature and agitation rate to infer slurry density online. It is argued that the model, which infers slurry density from IR spectra, gives more accurate estimation of the fractional composition of two diastereomers. Furthermore, the paper also successfully demonstrates through a third and a more general PLS model the ability of real time monitoring several crystallization process variables by the use of the aforementioned online measurements. Besides monitoring the changing diastereomeric composition and slurry density, one can also monitor the solute concentration of each diastereomer in a complex crystallization system. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071179q [article] Online estimation and monitoring of diastereomeric resolution using FBRM, ATR-FTIR, and raman spectroscopy [texte imprimé] / Sze-Wing Wong, Auteur ; Christos Georgakis, Auteur ; Gregory D. Botsaris, Auteur . - 2008 . - p. 5576–5584. Bibliogr. p. 5583-5584 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5576–5584 Mots-clés : Diastereomers -- fractional solid composition  Raman spectroscopy Résumé : This paper first demonstrates that the estimation of fractional solid composition of two diastereomers is possible by incorporating Raman spectra, slurry density, and temperature into a partial least squares (PLS) model. Since slurry density measurement is not readily available, the online estimation is obtained through another PLS model that utilizes online Raman spectroscopy, focus beam reflectance measurement (FBRM), attenuated total reflection Fourier transform infrared (ATR-FTIR), and/or additional process information such as temperature and agitation rate to infer slurry density online. It is argued that the model, which infers slurry density from IR spectra, gives more accurate estimation of the fractional composition of two diastereomers. Furthermore, the paper also successfully demonstrates through a third and a more general PLS model the ability of real time monitoring several crystallization process variables by the use of the aforementioned online measurements. Besides monitoring the changing diastereomeric composition and slurry density, one can also monitor the solute concentration of each diastereomer in a complex crystallization system. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071179q

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Using wavelets for solving SMB separation process models / Hongmei Yao in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5585–5593 Titre : Using wavelets for solving SMB separation process models Type de document : texte imprimé Auteurs : Hongmei Yao, Auteur ; Yu-Chu Tian, Auteur ; Moses O. Tadé, Auteur Année de publication : 2008 Article en page(s) : p. 5585–5593 Note générale : Bibliogr. p. 5592-5593 Langues : Anglais (eng) Mots-clés : Simulated moving bed separation  Wavelet-based method Résumé : With the expanding applications of the simulated moving bed (SMB) chromatography technology in various industries, it becomes increasingly significant to systematically investigate SMB process modeling, simulation, and model-based control design. How to control an SMB process effectively is a significant and challenging problem at the frontier of process systems engineering research as well as industrial operation. Addressing the challenges in this area, this paper reviews recent advances in modeling and simulation of SMB separation processes and also clearly identifies the limitation of the existing modeling techniques in industrial applications. To facilitate SMB process modeling, the paper analyses the structure of the existing models for a better understanding of the functionality and suitability of each model. It is our belief that the effort on model development for process control can be made in two aspects: obtaining the sufficiently accurate model with simple representation and good robustness, and development of computationally efficient algorithms for solving the model equations which ultimately capture the process dynamics. Case studies are carried out to demonstrate the key concepts of process modeling and numerical solution of the models. The wavelet-based methods that we recently investigated are highlighted. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071246g [article] Using wavelets for solving SMB separation process models [texte imprimé] / Hongmei Yao, Auteur ; Yu-Chu Tian, Auteur ; Moses O. Tadé, Auteur . - 2008 . - p. 5585–5593. Bibliogr. p. 5592-5593 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5585–5593 Mots-clés : Simulated moving bed separation  Wavelet-based method Résumé : With the expanding applications of the simulated moving bed (SMB) chromatography technology in various industries, it becomes increasingly significant to systematically investigate SMB process modeling, simulation, and model-based control design. How to control an SMB process effectively is a significant and challenging problem at the frontier of process systems engineering research as well as industrial operation. Addressing the challenges in this area, this paper reviews recent advances in modeling and simulation of SMB separation processes and also clearly identifies the limitation of the existing modeling techniques in industrial applications. To facilitate SMB process modeling, the paper analyses the structure of the existing models for a better understanding of the functionality and suitability of each model. It is our belief that the effort on model development for process control can be made in two aspects: obtaining the sufficiently accurate model with simple representation and good robustness, and development of computationally efficient algorithms for solving the model equations which ultimately capture the process dynamics. Case studies are carried out to demonstrate the key concepts of process modeling and numerical solution of the models. The wavelet-based methods that we recently investigated are highlighted. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071246g

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Dyes removal from simulated and industrial textile effluents by dissolved-air and dispersed-air flotation techniques / Evangelia K. Dafnopatidou in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5594–5601 Titre : Dyes removal from simulated and industrial textile effluents by dissolved-air and dispersed-air flotation techniques Type de document : texte imprimé Auteurs : Evangelia K. Dafnopatidou, Auteur ; Nikolaos K. Lazaridis, Auteur Année de publication : 2008 Article en page(s) : p. 5594–5601 Note générale : Bibliogr. p. 5600-5601 Langues : Anglais (eng) Mots-clés : Dyestuffs  Kinetic model  Dispersed-air flotation Résumé : In this study, which complements the previously published work of this team on dyes removal, dispersed- and dissolved-air flotation were employed in order to remove dyestuffs from simulated and industrial textile effluents, originating either from the dyeing mill or from the equalization tank of a dye-house. The influence of initial dyes, sodium chloride, and surfactant and polyelectrolyte content was investigated. A first-order kinetic model could adequately describe dispersed-air flotation time profiles. The results show that both flotation techniques are realistic methods for the treatment of effluents originating from the equalization tank by employing 100 mg/L cetyltrimethylammonium bromide (CTAB). Dissolved-air flotation can be used for effluents originating from the dyeing mill with the addition of polyelectrolyte, flocculant, dodecyl hydrogen sulfate sodium salt (SDS), and CTAB. Dye removal was higher than 97%, and the residual dye content could be lower than the limit of 300 American Dyestuff Manufacturer’s Institute units. Furthermore, the possibility for reuse of the decolorized water was evaluated in dyeing experiments. However, the results should be confirmed in full-scale experiments. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071235n [article] Dyes removal from simulated and industrial textile effluents by dissolved-air and dispersed-air flotation techniques [texte imprimé] / Evangelia K. Dafnopatidou, Auteur ; Nikolaos K. Lazaridis, Auteur . - 2008 . - p. 5594–5601. Bibliogr. p. 5600-5601 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5594–5601 Mots-clés : Dyestuffs  Kinetic model  Dispersed-air flotation Résumé : In this study, which complements the previously published work of this team on dyes removal, dispersed- and dissolved-air flotation were employed in order to remove dyestuffs from simulated and industrial textile effluents, originating either from the dyeing mill or from the equalization tank of a dye-house. The influence of initial dyes, sodium chloride, and surfactant and polyelectrolyte content was investigated. A first-order kinetic model could adequately describe dispersed-air flotation time profiles. The results show that both flotation techniques are realistic methods for the treatment of effluents originating from the equalization tank by employing 100 mg/L cetyltrimethylammonium bromide (CTAB). Dissolved-air flotation can be used for effluents originating from the dyeing mill with the addition of polyelectrolyte, flocculant, dodecyl hydrogen sulfate sodium salt (SDS), and CTAB. Dye removal was higher than 97%, and the residual dye content could be lower than the limit of 300 American Dyestuff Manufacturer’s Institute units. Furthermore, the possibility for reuse of the decolorized water was evaluated in dyeing experiments. However, the results should be confirmed in full-scale experiments. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071235n

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Separation of CO2 from light gas mixtures using ion-exchanged silicoaluminophosphate nanoporous sorbents / Milton E. Rivera-Ramos in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5602–5610 Titre : Separation of CO2 from light gas mixtures using ion-exchanged silicoaluminophosphate nanoporous sorbents Type de document : texte imprimé Auteurs : Milton E. Rivera-Ramos, Auteur ; Gerardo J. Ruiz-Mercado, Auteur ; Arturo J. Hernandez-Maldonado, Auteur Année de publication : 2008 Article en page(s) : p. 5602–5610 Note générale : Bibliogr. p. 5609-5610 Langues : Anglais (eng) Mots-clés : Light gas mixtures  Adsorption equilibria  Ion-quadrupole interactions Résumé : Na+-SAPO-34 sorbents were ion-exchanged with several individual metal cations to study their effect on the adsorption of similar size light gases. Measurements of pure component adsorption equilibria, with emphasis on CO2, were performed at different temperatures (273−348 K) and pressures ( En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071309v [article] Separation of CO2 from light gas mixtures using ion-exchanged silicoaluminophosphate nanoporous sorbents [texte imprimé] / Milton E. Rivera-Ramos, Auteur ; Gerardo J. Ruiz-Mercado, Auteur ; Arturo J. Hernandez-Maldonado, Auteur . - 2008 . - p. 5602–5610. Bibliogr. p. 5609-5610 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5602–5610 Mots-clés : Light gas mixtures  Adsorption equilibria  Ion-quadrupole interactions Résumé : Na+-SAPO-34 sorbents were ion-exchanged with several individual metal cations to study their effect on the adsorption of similar size light gases. Measurements of pure component adsorption equilibria, with emphasis on CO2, were performed at different temperatures (273−348 K) and pressures ( En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071309v

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Irreversible chemical potential and shear-induced diffusion in crossflow filtration / Albert S. Kim in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5611–5614 Titre : Irreversible chemical potential and shear-induced diffusion in crossflow filtration Type de document : texte imprimé Auteurs : Albert S. Kim, Auteur ; Yuewei Liu, Auteur Année de publication : 2008 Article en page(s) : p. 5611–5614 Note générale : Bibliogr. p. 5614 Langues : Anglais (eng) Mots-clés : Crossflow filtration  Colloidal back-diffusion  Shear-induced diffusion Résumé : Nonequilibrium themodynamics is used in a novel way to fundamentally investigate colloidal back-diffusion during crossflow membrane filtration. A generalized chemical potential is assumed as a superposition of equilibrium and irreversible contributions, which are proven to originate from Brownian and shear-induced diffusion, respectively. As a result, an effective drag force is derived for a particle that is simultaneously undergoing both Brownian and shear-induced diffusion in a sheared concentrated suspension. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714403 [article] Irreversible chemical potential and shear-induced diffusion in crossflow filtration [texte imprimé] / Albert S. Kim, Auteur ; Yuewei Liu, Auteur . - 2008 . - p. 5611–5614. Bibliogr. p. 5614 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5611–5614 Mots-clés : Crossflow filtration  Colloidal back-diffusion  Shear-induced diffusion Résumé : Nonequilibrium themodynamics is used in a novel way to fundamentally investigate colloidal back-diffusion during crossflow membrane filtration. A generalized chemical potential is assumed as a superposition of equilibrium and irreversible contributions, which are proven to originate from Brownian and shear-induced diffusion, respectively. As a result, an effective drag force is derived for a particle that is simultaneously undergoing both Brownian and shear-induced diffusion in a sheared concentrated suspension. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714403

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Isotherms, isosteres, and enthalpy of adsorption of 1,2-dichloroethane from aqueous solution onto activated carbons / Robert Pełech in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5615-5622 Titre : Isotherms, isosteres, and enthalpy of adsorption of 1,2-dichloroethane from aqueous solution onto activated carbons Type de document : texte imprimé Auteurs : Robert Pełech, Auteur Année de publication : 2008 Article en page(s) : p. 5615-5622 Note générale : Bibliogr. p. 5622 Langues : Anglais (eng) Mots-clés : 1,2-dichloroethane -- adsorption  Dubinin-Astakhov equation  Freundlich Résumé : In this work the adsorption of 1,2-dichloroethane from aqueous solutions onto DTO, AG5, and WD-ekstra activated carbons has been studied. The adsorption isotherms at the range of temperatures 298-343 K have been described by the Freundlich and Dubinin-Astakhov equations. The characteristic curves of the adsorption process have been determined. It was found out that the temperature dependence of the adsorption equilibrium was described well by the Dubinin-Astakhov model. The isosteric enthalpy of the adsorption was assigned. To describe the dependence of the adsorption isosteric enthalpy on the filling degree, the Do model and the combinations of the van’t Hoff and Dubinin-Astakhov equations in a form of the logarithmic equation were used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715862 [article] Isotherms, isosteres, and enthalpy of adsorption of 1,2-dichloroethane from aqueous solution onto activated carbons [texte imprimé] / Robert Pełech, Auteur . - 2008 . - p. 5615-5622. Bibliogr. p. 5622 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5615-5622 Mots-clés : 1,2-dichloroethane -- adsorption  Dubinin-Astakhov equation  Freundlich Résumé : In this work the adsorption of 1,2-dichloroethane from aqueous solutions onto DTO, AG5, and WD-ekstra activated carbons has been studied. The adsorption isotherms at the range of temperatures 298-343 K have been described by the Freundlich and Dubinin-Astakhov equations. The characteristic curves of the adsorption process have been determined. It was found out that the temperature dependence of the adsorption equilibrium was described well by the Dubinin-Astakhov model. The isosteric enthalpy of the adsorption was assigned. To describe the dependence of the adsorption isosteric enthalpy on the filling degree, the Do model and the combinations of the van’t Hoff and Dubinin-Astakhov equations in a form of the logarithmic equation were used. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0715862

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Adsorptive removal of as(III) from aqueous solution by zr(IV)-loaded collagen fiber / Xin Huang in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5623-5628 Titre : Adsorptive removal of as(III) from aqueous solution by zr(IV)-loaded collagen fiber Type de document : texte imprimé Auteurs : Xin Huang, Auteur ; Limin Jiao, Auteur ; Xuepin Liao, Auteur Année de publication : 2008 Article en page(s) : p. 5623-5628 Note générale : Bibliogr. p. 5627-5628 Langues : Anglais (eng) Mots-clés : Arsenite (III)  ZrCF  Adsorption Résumé : Compared with arsenate [As(V)], arsenite [As(III)] is more toxic to human health and more difficult to be removed from aqueous solution. In this study, a novel adsorbent, Zr(IV)-loaded collagen fiber (ZrCF), was prepared, and its adsorption characteristics to As(III) were investigated. It was found that ZrCF can effectively remove As(III) from aqueous solution in the pH range of 9.0-12.0. The maximum adsorption capacity of As(III) by ZrCF reached up to 54.02 mg As/g when the initial concentration of As(III) was 73.00 mg/L at 303 K and pH 11.0. The adsorption isotherms of ZrCF to As(III) were well fitted by the Langmuir-Freundlich equation. The adsorption kinetic experimental data were well described by the pseudo-second-order rate equation, and the calculated adsorption capacities were close to those obtained by experiments. The leakage of zirconium loaded on ZrCF was negligible during adsorption process. Therefore, this study indicates that ZrCF is a promising adsorbent for As(III) removal from aqueous solution. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071608k [article] Adsorptive removal of as(III) from aqueous solution by zr(IV)-loaded collagen fiber [texte imprimé] / Xin Huang, Auteur ; Limin Jiao, Auteur ; Xuepin Liao, Auteur . - 2008 . - p. 5623-5628. Bibliogr. p. 5627-5628 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5623-5628 Mots-clés : Arsenite (III)  ZrCF  Adsorption Résumé : Compared with arsenate [As(V)], arsenite [As(III)] is more toxic to human health and more difficult to be removed from aqueous solution. In this study, a novel adsorbent, Zr(IV)-loaded collagen fiber (ZrCF), was prepared, and its adsorption characteristics to As(III) were investigated. It was found that ZrCF can effectively remove As(III) from aqueous solution in the pH range of 9.0-12.0. The maximum adsorption capacity of As(III) by ZrCF reached up to 54.02 mg As/g when the initial concentration of As(III) was 73.00 mg/L at 303 K and pH 11.0. The adsorption isotherms of ZrCF to As(III) were well fitted by the Langmuir-Freundlich equation. The adsorption kinetic experimental data were well described by the pseudo-second-order rate equation, and the calculated adsorption capacities were close to those obtained by experiments. The leakage of zirconium loaded on ZrCF was negligible during adsorption process. Therefore, this study indicates that ZrCF is a promising adsorbent for As(III) removal from aqueous solution. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071608k

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Multicomponent sorptive removal of toxics pyridine, 2-picoline, and 4-picoline from aqueous solution by bagasse fly ash / D. H Lataye in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5629-5635 Titre : Multicomponent sorptive removal of toxics pyridine, 2-picoline, and 4-picoline from aqueous solution by bagasse fly ash : optimization of process parameters Type de document : texte imprimé Auteurs : D. H Lataye, Auteur ; I. M Mishra, Auteur ; I. D Mall, Auteur Année de publication : 2008 Article en page(s) : p. 5629-5635 Note générale : Bibliogr. p. 5635 Langues : Anglais (eng) Mots-clés : Pyridine -- simultaneous removal  Bagasse fly ash  Taguchi’s design Résumé : The present paper deals with the simultaneous removal of Pyridine (Py) and its derivatives 2-picoline (2Pi) and 4-picoline (4Pi) by adsorption from aqueous solutions using bagasse fly ash (BFA) as an adsorbent. The effect of various parameters, such as adsorbent dose (m), initial pH (pH0), contact time (t), initial concentrations (C0,i), and temperature (T), on the simultaneous adsorption of Py, 2Pi, and 4Pi have been studied using Taguchi’s design of experimental methodology. Each parameter has been tested at three levels to see their effect on the selected response characteristic, i.e., the total sorptive uptake of Py, 2Pi, and 4Pi, by BFA (qtot, mg g−1), and the optimal level of each parameter for maximizing qtot has been determined. The analysis of variance (ANOVA) shows that the adsorbent dose, m, is the most significant parameter with 35.65% and 10.50% contribution to the qtot and signal-to-noise (S/N) ratio data, respectively. The contribution of interactions between initial concentrations and other parameters is also significant. Confirmation adsorption experiments carried out at the optimal values of the parameters validated the effectiveness of the Taguchi’s design of experimental methodology for multicomponent adsorption of organics from aqueous solution. The percent removal (and the sorptive uptake) of Py, 2Pi, and 4Pi was found to be ∼50% (∼12.38 mg g−1), ∼68% (∼17 mg g−1), and ∼69% (∼17.01 mg g−1), respectively, with a total uptake of all the components at optimal conditions being 46.39 mg g−1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716161 [article] Multicomponent sorptive removal of toxics pyridine, 2-picoline, and 4-picoline from aqueous solution by bagasse fly ash : optimization of process parameters [texte imprimé] / D. H Lataye, Auteur ; I. M Mishra, Auteur ; I. D Mall, Auteur . - 2008 . - p. 5629-5635. Bibliogr. p. 5635 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5629-5635 Mots-clés : Pyridine -- simultaneous removal  Bagasse fly ash  Taguchi’s design Résumé : The present paper deals with the simultaneous removal of Pyridine (Py) and its derivatives 2-picoline (2Pi) and 4-picoline (4Pi) by adsorption from aqueous solutions using bagasse fly ash (BFA) as an adsorbent. The effect of various parameters, such as adsorbent dose (m), initial pH (pH0), contact time (t), initial concentrations (C0,i), and temperature (T), on the simultaneous adsorption of Py, 2Pi, and 4Pi have been studied using Taguchi’s design of experimental methodology. Each parameter has been tested at three levels to see their effect on the selected response characteristic, i.e., the total sorptive uptake of Py, 2Pi, and 4Pi, by BFA (qtot, mg g−1), and the optimal level of each parameter for maximizing qtot has been determined. The analysis of variance (ANOVA) shows that the adsorbent dose, m, is the most significant parameter with 35.65% and 10.50% contribution to the qtot and signal-to-noise (S/N) ratio data, respectively. The contribution of interactions between initial concentrations and other parameters is also significant. Confirmation adsorption experiments carried out at the optimal values of the parameters validated the effectiveness of the Taguchi’s design of experimental methodology for multicomponent adsorption of organics from aqueous solution. The percent removal (and the sorptive uptake) of Py, 2Pi, and 4Pi was found to be ∼50% (∼12.38 mg g−1), ∼68% (∼17 mg g−1), and ∼69% (∼17.01 mg g−1), respectively, with a total uptake of all the components at optimal conditions being 46.39 mg g−1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0716161

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Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 1. vapor-liquid equilibria / Andreas Grenner in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5636–5650 Titre : Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 1. vapor-liquid equilibria Type de document : texte imprimé Auteurs : Andreas Grenner, Auteur ; Ioannis Tsivintzelis, Auteur ; Ioannis G. Economou, Auteur Année de publication : 2008 Article en page(s) : p. 5636–5650 Note générale : Bibliogr. p. 5649-5650 Langues : Anglais (eng) Mots-clés : Nonrandom hydrogen bonding -- vapor−  liquid equilibrium models  Perturbed-chain-statistical associating fluid theory Résumé : A standard database for the validation of vapor-liquid equilibrium (VLE) models was used to evaluate prediction and correlation accuracy of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (PC-SAFT). Pure-component parameters for the models were taken from literature or estimated in this work. Generalized pure-component parameters were fitted to pure-component vapor-pressure and liquid-density data. For the majority of the mixtures examined, satisfactory results were obtained. For a number of mixtures, different modeling approaches were applied to improve the results, such as incorporation of cross-association between nonself-associating fluids or induced association for mixtures of polar nonassociating and self-associating fluids. For both models, the overall deviations from experimental data are similar, and none of the models is found to be overall superior over the other. However, for specific mixtures, one model often performs better than the other. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071381t [article] Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 1. vapor-liquid equilibria [texte imprimé] / Andreas Grenner, Auteur ; Ioannis Tsivintzelis, Auteur ; Ioannis G. Economou, Auteur . - 2008 . - p. 5636–5650. Bibliogr. p. 5649-5650 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5636–5650 Mots-clés : Nonrandom hydrogen bonding -- vapor−  liquid equilibrium models  Perturbed-chain-statistical associating fluid theory Résumé : A standard database for the validation of vapor-liquid equilibrium (VLE) models was used to evaluate prediction and correlation accuracy of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (PC-SAFT). Pure-component parameters for the models were taken from literature or estimated in this work. Generalized pure-component parameters were fitted to pure-component vapor-pressure and liquid-density data. For the majority of the mixtures examined, satisfactory results were obtained. For a number of mixtures, different modeling approaches were applied to improve the results, such as incorporation of cross-association between nonself-associating fluids or induced association for mixtures of polar nonassociating and self-associating fluids. For both models, the overall deviations from experimental data are similar, and none of the models is found to be overall superior over the other. However, for specific mixtures, one model often performs better than the other. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071381t

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Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 2. liquid-liquid equilibria and prediction of monomer fraction in hydrogen bonding systems / Ioannis Tsivintzelis in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5651–5659 Titre : Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 2. liquid-liquid equilibria and prediction of monomer fraction in hydrogen bonding systems Type de document : texte imprimé Auteurs : Ioannis Tsivintzelis, Auteur ; Andreas Grenner, Auteur Année de publication : 2008 Article en page(s) : p. 5651–5659 Note générale : Bibliogr. p. 5658-5659 Langues : Anglais (eng) Mots-clés : Nonrandom hydrogen bonding theory  Simplified perturbed-chain-statistical associating fluid Liquid-liquid equilibria model Résumé : Two statistical thermodynamic models, the nonrandom hydrogen bonding (NRHB) theory, which is a compressible lattice model, and the simplified perturbed-chain−statistical associating fluid theory (sPC-SAFT), which is based on Wertheim’s perturbation theory, were used to model liquid−liquid equilibria and predict the fraction of non-hydrogen bonded molecules in various hydrogen bonding mixtures. Carefully selected binary mixtures, which include water−hydrocarbon, 1-alkanol−hydrocarbon, water−1-alkanol, and glycol−hydrocarbon, were used to benchmark the accuracy of the models. Both models yielded satisfactory and often very similar results for the phase behavior of the investigated mixtures. sPC-SAFT yielded more accurate predictions, while NRHB yielded more accurate correlations, in mixtures of water with normal alkanes and cycloalkanes. In water−aromatic hydrocarbon mixtures, satisfactory correlations were obtained only when solvation was accounted for. Both models resulted in satisfactory correlations for all other mixtures, while for specific mixtures, one model may perform better than the other. Finally, both models, despite that they are based on totally different approaches for the treatment of hydrogen bonding, yielded similar predictions for the fraction of non-hydrogen bonded molecules (monomer fraction) in pure 1-alkanols and in 1-alkanol−n-hexane mixtures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071382l#afn1 [article] Evaluation of the nonrandom hydrogen bonding (NRHB) theory and the simplified perturbed-chain-statistical associating fluid theory (sPC-SAFT). 2. liquid-liquid equilibria and prediction of monomer fraction in hydrogen bonding systems [texte imprimé] / Ioannis Tsivintzelis, Auteur ; Andreas Grenner, Auteur . - 2008 . - p. 5651–5659. Bibliogr. p. 5658-5659 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5651–5659 Mots-clés : Nonrandom hydrogen bonding theory  Simplified perturbed-chain-statistical associating fluid Liquid-liquid equilibria model Résumé : Two statistical thermodynamic models, the nonrandom hydrogen bonding (NRHB) theory, which is a compressible lattice model, and the simplified perturbed-chain−statistical associating fluid theory (sPC-SAFT), which is based on Wertheim’s perturbation theory, were used to model liquid−liquid equilibria and predict the fraction of non-hydrogen bonded molecules in various hydrogen bonding mixtures. Carefully selected binary mixtures, which include water−hydrocarbon, 1-alkanol−hydrocarbon, water−1-alkanol, and glycol−hydrocarbon, were used to benchmark the accuracy of the models. Both models yielded satisfactory and often very similar results for the phase behavior of the investigated mixtures. sPC-SAFT yielded more accurate predictions, while NRHB yielded more accurate correlations, in mixtures of water with normal alkanes and cycloalkanes. In water−aromatic hydrocarbon mixtures, satisfactory correlations were obtained only when solvation was accounted for. Both models resulted in satisfactory correlations for all other mixtures, while for specific mixtures, one model may perform better than the other. Finally, both models, despite that they are based on totally different approaches for the treatment of hydrogen bonding, yielded similar predictions for the fraction of non-hydrogen bonded molecules (monomer fraction) in pure 1-alkanols and in 1-alkanol−n-hexane mixtures. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071382l#afn1

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Phase equilibrium modelling for mixtures with acetic acid using an association equation of state / Nuria Muro-Suné, in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5660–5668 Titre : Phase equilibrium modelling for mixtures with acetic acid using an association equation of state Type de document : texte imprimé Auteurs : Nuria Muro-Suné,, Auteur ; Georgios M. Kontogeorgis, Auteur ; Nicolas von Solms, Auteur ; Michael L. Michelsen, Auteur Année de publication : 2008 Article en page(s) : p. 5660–5668 Note générale : Bibliogr. p. 5668 Langues : Anglais (eng) Mots-clés : Acetic acid  Equation of state Résumé : Acetic acid is a very important compound in the chemical industry with applications both as solvent and intermediate in the production of, e.g., polyesters. The design of these processes requires knowledge of the phase equilibria of mixtures containing acetic acid and a wide variety of compounds over extended temperature and pressure ranges. From the scientific point of view, modeling of such equilibria is challenging because of the complex association and solvation phenomena present. In this work, a previously developed association equation of state (cubic-plus-association, CPA) is applied to a wide variety of mixtures containing acetic acid, including gas solubilities, cross-associating systems (with water and alcohols), and polar chemicals like acetone and esters. Vapor−liquid and liquid−liquid equilibria are considered for both binary and ternary mixtures. With the exception of a somewhat inferior performance for the water−acetic acid VLE, which does not seem to affect substantially the performance for the multicomponent systems studied, CPA performs satisfactorily in most cases, using a single interaction parameter over extensive temperature ranges. For accurate description of water−acetic acid, use of the Huron−Vidal mixing rule for the energy parameter of CPA can yield a satisfactory correlation at the cost of more interaction parameters. En ligne : pubs.acs.org/doi/abs/10.1021/ie071205k [article] Phase equilibrium modelling for mixtures with acetic acid using an association equation of state [texte imprimé] / Nuria Muro-Suné,, Auteur ; Georgios M. Kontogeorgis, Auteur ; Nicolas von Solms, Auteur ; Michael L. Michelsen, Auteur . - 2008 . - p. 5660–5668. Bibliogr. p. 5668 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5660–5668 Mots-clés : Acetic acid  Equation of state Résumé : Acetic acid is a very important compound in the chemical industry with applications both as solvent and intermediate in the production of, e.g., polyesters. The design of these processes requires knowledge of the phase equilibria of mixtures containing acetic acid and a wide variety of compounds over extended temperature and pressure ranges. From the scientific point of view, modeling of such equilibria is challenging because of the complex association and solvation phenomena present. In this work, a previously developed association equation of state (cubic-plus-association, CPA) is applied to a wide variety of mixtures containing acetic acid, including gas solubilities, cross-associating systems (with water and alcohols), and polar chemicals like acetone and esters. Vapor−liquid and liquid−liquid equilibria are considered for both binary and ternary mixtures. With the exception of a somewhat inferior performance for the water−acetic acid VLE, which does not seem to affect substantially the performance for the multicomponent systems studied, CPA performs satisfactorily in most cases, using a single interaction parameter over extensive temperature ranges. For accurate description of water−acetic acid, use of the Huron−Vidal mixing rule for the energy parameter of CPA can yield a satisfactory correlation at the cost of more interaction parameters. En ligne : pubs.acs.org/doi/abs/10.1021/ie071205k

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Optimization of productivity and thermodynamic performance of metabolic pathways / Mian Xu in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5669–5679 Titre : Optimization of productivity and thermodynamic performance of metabolic pathways Type de document : texte imprimé Auteurs : Mian Xu, Auteur ; Robin Smith, Auteur ; Jhuma Sadhukhan, Auteur Année de publication : 2008 Article en page(s) : p. 5669–5679 Note générale : Bibliogr. p. 5679 Langues : Anglais (eng) Mots-clés : Cellular metabolic systems  Pathway analysis  Flux balance Gibbs free energy Résumé : In this contribution, a novel optimization strategy has been presented that combines the metabolic flux analysis and pathway identification with the thermodynamic analysis of cellular metabolic systems. First, an optimal metabolic flux distribution among elementary pathways is identified by LP optimization subject to constraints on flux balance analysis, pathway analysis, and negative Gibbs free energy change for pathways, for achieving the maximum yield of products. The Gibbs free energy change for pathways is calculated from the new transformed Gibbs free energy of formation of external metabolites and cofactors that are in stoichiometric balance in metabolic pathways. The consideration of thermodynamic constraints on pathways ensures the selection of feasible pathways. Thereafter, the Gibbs free energy change of pathways is minimized to predict the optimal reaction conditions that facilitate such pathways. Thus, the optimization approach derives the optimal pathway distribution and conditions for the best performance of cellular systems. The effectiveness of the methodology is demonstrated by a case study on the optimization of pentose phosphate pathway (PPP) and the glycolysis cycle of the insilico Escherichia coli. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070352f [article] Optimization of productivity and thermodynamic performance of metabolic pathways [texte imprimé] / Mian Xu, Auteur ; Robin Smith, Auteur ; Jhuma Sadhukhan, Auteur . - 2008 . - p. 5669–5679. Bibliogr. p. 5679 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5669–5679 Mots-clés : Cellular metabolic systems  Pathway analysis  Flux balance Gibbs free energy Résumé : In this contribution, a novel optimization strategy has been presented that combines the metabolic flux analysis and pathway identification with the thermodynamic analysis of cellular metabolic systems. First, an optimal metabolic flux distribution among elementary pathways is identified by LP optimization subject to constraints on flux balance analysis, pathway analysis, and negative Gibbs free energy change for pathways, for achieving the maximum yield of products. The Gibbs free energy change for pathways is calculated from the new transformed Gibbs free energy of formation of external metabolites and cofactors that are in stoichiometric balance in metabolic pathways. The consideration of thermodynamic constraints on pathways ensures the selection of feasible pathways. Thereafter, the Gibbs free energy change of pathways is minimized to predict the optimal reaction conditions that facilitate such pathways. Thus, the optimization approach derives the optimal pathway distribution and conditions for the best performance of cellular systems. The effectiveness of the methodology is demonstrated by a case study on the optimization of pentose phosphate pathway (PPP) and the glycolysis cycle of the insilico Escherichia coli. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070352f

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Dispersion polymerization of methyl methacrylate using poly(HDFDMA-co-MMA) as a surfactant in supercritical carbon dioxide / Jungin Shin in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5680–5685 Titre : Dispersion polymerization of methyl methacrylate using poly(HDFDMA-co-MMA) as a surfactant in supercritical carbon dioxide Type de document : texte imprimé Auteurs : Jungin Shin, Auteur ; Kyung Shil Oh, Auteur ; Won Bae, Auteur ; Youn Woo Lee, Auteur Année de publication : 2008 Article en page(s) : p. 5680–5685 Note générale : Bibliogr. p. 5684-5685 Langues : Anglais (eng) Mots-clés : Methyl methacrylate  Dispersion polymerization Résumé : New surfactants, random copolymers of heptadecafluorodecyl methacrylate (HDFDMA) and methyl methacrylate (MMA), were synthesized at 343.2 K and 30 MPa in supercritical carbon dioxide (scCO2) with varying HDFDMA/MMA ratios. 1H NMR and FT-IR were used to confirm the structure and to determine the composition of the resulting copolymers. The phase behavior of poly(HDFDMA-co-MMA) in CO2 was obtained by means of a variable volume view cell, which will be used to select the polymerization condition. After that, dispersion polymerization of methyl methacrylate (MMA) in scCO2 was performed using 2,2′-azobis(isobutyronitrile) (AIBN) as the initiator and poly(HDFDMA-co-MMA) with various MMA mole fraction as a surfactant. The new surfactant, poly(HDFDMA-co-MMA), whose MMA content is lower than 12.3 wt %, shows comparable capacity to produce PMMA particles compared to poly(HDFDMA) surfactant. The resulting PMMA particles, such as those produced using poly(HDFDMA) homopolymer as a surfactant, could also be produced with poly(HDFDMA-co-MMA) up to 12.3 wt % MMA. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070995v [article] Dispersion polymerization of methyl methacrylate using poly(HDFDMA-co-MMA) as a surfactant in supercritical carbon dioxide [texte imprimé] / Jungin Shin, Auteur ; Kyung Shil Oh, Auteur ; Won Bae, Auteur ; Youn Woo Lee, Auteur . - 2008 . - p. 5680–5685. Bibliogr. p. 5684-5685 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5680–5685 Mots-clés : Methyl methacrylate  Dispersion polymerization Résumé : New surfactants, random copolymers of heptadecafluorodecyl methacrylate (HDFDMA) and methyl methacrylate (MMA), were synthesized at 343.2 K and 30 MPa in supercritical carbon dioxide (scCO2) with varying HDFDMA/MMA ratios. 1H NMR and FT-IR were used to confirm the structure and to determine the composition of the resulting copolymers. The phase behavior of poly(HDFDMA-co-MMA) in CO2 was obtained by means of a variable volume view cell, which will be used to select the polymerization condition. After that, dispersion polymerization of methyl methacrylate (MMA) in scCO2 was performed using 2,2′-azobis(isobutyronitrile) (AIBN) as the initiator and poly(HDFDMA-co-MMA) with various MMA mole fraction as a surfactant. The new surfactant, poly(HDFDMA-co-MMA), whose MMA content is lower than 12.3 wt %, shows comparable capacity to produce PMMA particles compared to poly(HDFDMA) surfactant. The resulting PMMA particles, such as those produced using poly(HDFDMA) homopolymer as a surfactant, could also be produced with poly(HDFDMA-co-MMA) up to 12.3 wt % MMA. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070995v

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Laser diagnostic investigation of the bubble eruption patterns in the freeboard of fluidized beds. 1. optimization of acetone planar laser induced fluorescence measurements / Georg Hartung in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5686–5697 Titre : Laser diagnostic investigation of the bubble eruption patterns in the freeboard of fluidized beds. 1. optimization of acetone planar laser induced fluorescence measurements Type de document : texte imprimé Auteurs : Georg Hartung, Auteur ; Christoph R. Müller, Auteur ; Johan Hult, Auteur ; John S. Dennis, Auteur Année de publication : 2008 Article en page(s) : p. 5686–5697 Note générale : Bibliogr. p. 5696-5697 Langues : Anglais (eng) Mots-clés : Freeboard gas -- mixing  Acetone PLIF  Bubble eruption pattern Résumé : Here, the mixing of the freeboard gas with the gas of single bubbles and a continuous stream of bubbles is investigated using acetone planar laser induced fluorescence (PLIF), a technique only recently introduced to fluidized bed research [Solimene et al. Chem. Eng. Sci.2007, 62, 94]. Various improvements with respect to laser diagnostics are presented leading to optimal signals from acetone PLIF. The results obtained are compared with models presented in the literature. The observed bubble eruption pattern generally corresponds to the models proposed by Levy and Lockwood [ AIChE J.1983, 29, 889], Yórquez-Ramirez and Duursma [ Powder Technol.2001, 116, 76], and Solimene et al. [ Chem. Eng. Sci.2007, 62, 94]. No difference was observed between the eruption patterns of a single bubble compared to a continuous stream of bubbles. In contrast to the models of Yórquez-Ramirez and Duursma and Solimene et al., five different patterns of the release of gas at a dome formed by a rising bubble are observed. An explanation for the formation of a thin layer of acetone after the eruption of a bubbles is given. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0713543 [article] Laser diagnostic investigation of the bubble eruption patterns in the freeboard of fluidized beds. 1. optimization of acetone planar laser induced fluorescence measurements [texte imprimé] / Georg Hartung, Auteur ; Christoph R. Müller, Auteur ; Johan Hult, Auteur ; John S. Dennis, Auteur . - 2008 . - p. 5686–5697. Bibliogr. p. 5696-5697 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5686–5697 Mots-clés : Freeboard gas -- mixing  Acetone PLIF  Bubble eruption pattern Résumé : Here, the mixing of the freeboard gas with the gas of single bubbles and a continuous stream of bubbles is investigated using acetone planar laser induced fluorescence (PLIF), a technique only recently introduced to fluidized bed research [Solimene et al. Chem. Eng. Sci.2007, 62, 94]. Various improvements with respect to laser diagnostics are presented leading to optimal signals from acetone PLIF. The results obtained are compared with models presented in the literature. The observed bubble eruption pattern generally corresponds to the models proposed by Levy and Lockwood [ AIChE J.1983, 29, 889], Yórquez-Ramirez and Duursma [ Powder Technol.2001, 116, 76], and Solimene et al. [ Chem. Eng. Sci.2007, 62, 94]. No difference was observed between the eruption patterns of a single bubble compared to a continuous stream of bubbles. In contrast to the models of Yórquez-Ramirez and Duursma and Solimene et al., five different patterns of the release of gas at a dome formed by a rising bubble are observed. An explanation for the formation of a thin layer of acetone after the eruption of a bubbles is given. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0713543

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Modeling thermal conductivity of concentrated and mixed-solvent electrolyte systems / Peiming Wang in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5698–5709 Titre : Modeling thermal conductivity of concentrated and mixed-solvent electrolyte systems Type de document : texte imprimé Auteurs : Peiming Wang, Auteur ; Andrzej Anderko, Auteur Année de publication : 2008 Article en page(s) : p. 5698–5709 Note générale : Bibliogr. p. 5607-5609 Langues : Anglais (eng) Mots-clés : Solvent mixtures -- thermal conductivity  Electrolyte components Résumé : A comprehensive model has been developed for calculating the thermal conductivity of aqueous, nonaqueous, and mixed-solvent electrolyte systems ranging from dilute solutions to fused salts or pure solutes. The model consists of a correlation for calculating the thermal conductivity of solvent mixtures and a method for predicting the effect of electrolyte components. The thermal conductivity of multicomponent solvent mixtures can be represented using surface area parameters and thermal conductivities of pure solvents in conjunction with a single binary parameter per solvent pair. The effect of electrolytes is modeled by accounting for a contribution of individual ions, which is quantified by the Riedel coefficients, and a contribution of specific interactions between ions or neutral species. Formulations have been developed for the contributions of individual ions and species−species interactions to represent the effect of multiple solvents. In addition to solvent composition, the species−species interaction term is also a function of ionic strength. The model accurately reproduces experimental thermal conductivity data over a wide range of electrolyte concentrations in aqueous and nonaqueous systems. In particular, the model has been shown to be accurate for aqueous acids and bases (e.g., H2SO4, HNO3, H3PO4, NaOH, and KOH) up to the limit of a pure acid or base, various nitrates ranging from dilute solutions to fused salts, and other salts in water and various organic solvents. The model has been coupled with thermodynamic equilibrium calculations to reproduce the effects of complexation or other ionic reactions on thermal conductivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071373c [article] Modeling thermal conductivity of concentrated and mixed-solvent electrolyte systems [texte imprimé] / Peiming Wang, Auteur ; Andrzej Anderko, Auteur . - 2008 . - p. 5698–5709. Bibliogr. p. 5607-5609 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5698–5709 Mots-clés : Solvent mixtures -- thermal conductivity  Electrolyte components Résumé : A comprehensive model has been developed for calculating the thermal conductivity of aqueous, nonaqueous, and mixed-solvent electrolyte systems ranging from dilute solutions to fused salts or pure solutes. The model consists of a correlation for calculating the thermal conductivity of solvent mixtures and a method for predicting the effect of electrolyte components. The thermal conductivity of multicomponent solvent mixtures can be represented using surface area parameters and thermal conductivities of pure solvents in conjunction with a single binary parameter per solvent pair. The effect of electrolytes is modeled by accounting for a contribution of individual ions, which is quantified by the Riedel coefficients, and a contribution of specific interactions between ions or neutral species. Formulations have been developed for the contributions of individual ions and species−species interactions to represent the effect of multiple solvents. In addition to solvent composition, the species−species interaction term is also a function of ionic strength. The model accurately reproduces experimental thermal conductivity data over a wide range of electrolyte concentrations in aqueous and nonaqueous systems. In particular, the model has been shown to be accurate for aqueous acids and bases (e.g., H2SO4, HNO3, H3PO4, NaOH, and KOH) up to the limit of a pure acid or base, various nitrates ranging from dilute solutions to fused salts, and other salts in water and various organic solvents. The model has been coupled with thermodynamic equilibrium calculations to reproduce the effects of complexation or other ionic reactions on thermal conductivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071373c

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Kinetic study on bamboo pyrolysis / Edward L. K. Mui in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5710-5722 Titre : Kinetic study on bamboo pyrolysis Type de document : texte imprimé Auteurs : Edward L. K. Mui, Auteur ; W. H Cheung, Auteur ; Vinci K. C. Lee, Auteur ; Gordon McKay, Auteur Année de publication : 2008 Article en page(s) : p. 5710-5722 Note générale : Bibliogr. p. 5721-5722 Langues : Anglais (eng) Mots-clés : Bamboo -- pyrolysis  Runge-Kutta mechanism Résumé : Bamboo is an indigenous plant to many Asian countries; it is an extremely rapid growing plant, and with planned harvesting it can be produced as a sustainable raw material wood resource. The pyrolysis of bamboo has been studied to understand, model, and control the decomposition process as part of the overall process of producing activated carbons from bamboo. Different heating rates have been tested, and the pyrolysis mechanism has been modeled using the Runge-Kutta mechanism. The model has been applied assuming three-, four-, five-, and six-component reaction models. The best fit model, based on SSE values, is the six-component scheme using a Runge-Kutta solution methodology although the three-component reaction model correlates the data very well too. The basis for the selection of the six-component model is that each of the three main bamboo components, xylan, cellulose, and lignin, has one major decomposition step to volatiles and a minor decomposition to form char. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070763w [article] Kinetic study on bamboo pyrolysis [texte imprimé] / Edward L. K. Mui, Auteur ; W. H Cheung, Auteur ; Vinci K. C. Lee, Auteur ; Gordon McKay, Auteur . - 2008 . - p. 5710-5722. Bibliogr. p. 5721-5722 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5710-5722 Mots-clés : Bamboo -- pyrolysis  Runge-Kutta mechanism Résumé : Bamboo is an indigenous plant to many Asian countries; it is an extremely rapid growing plant, and with planned harvesting it can be produced as a sustainable raw material wood resource. The pyrolysis of bamboo has been studied to understand, model, and control the decomposition process as part of the overall process of producing activated carbons from bamboo. Different heating rates have been tested, and the pyrolysis mechanism has been modeled using the Runge-Kutta mechanism. The model has been applied assuming three-, four-, five-, and six-component reaction models. The best fit model, based on SSE values, is the six-component scheme using a Runge-Kutta solution methodology although the three-component reaction model correlates the data very well too. The basis for the selection of the six-component model is that each of the three main bamboo components, xylan, cellulose, and lignin, has one major decomposition step to volatiles and a minor decomposition to form char. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070763w

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Cubic two-state equation of state for associating fluids / Milton Medeiros in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5723-5733 Titre : Cubic two-state equation of state for associating fluids Type de document : texte imprimé Auteurs : Milton Medeiros, Auteur ; Pablo Téllez-Arredondo, Auteur Année de publication : 2008 Article en page(s) : p. 5723-5733 Note générale : Bibliogr. p. 5732-5733 Langues : Anglais (eng) Mots-clés : Two-state association model  Equation of state Résumé : The Kontogeorgis’ approach (CPA; Ind. Eng. Chem. Res. 1996, 35, 4310) was employed for the extension of the Soave−Redlich-Kwong (SRK) equation to associating systems. The two-state association model (TSAM) of Cerdeiriña et al. (J. Chem. Phys. 2004, 120, 6648) was modified and employed for describing the association contribution. The modification of TSAM consisted of developing an expression for the association contribution for the Helmholtz free energy as an explicit function of temperature and density, on the basis of the two-state approach. Similar to the CPA equation, the resulting cubic two-state (CTS) equation of state (EoS) has five parameters, three of them related to the nonspecific (physical) contribution and the other two related to the association. The CTS EoS is polynomial in volume and preserves the shape of a cubic equation in the region of positive volumes greater than the covolume, having one or three roots in this zone. For pure substances the equation is quartic, and it has analytical solution. The equation was fit to experimental vapor pressure and liquid density data of water, alcohols, and phenols, with very low deviations. The model was also employed to predict second virial coefficients of pure compounds, and phase equilibria of alcohol-alkane mixtures, using conventional mixing rules and one binary parameter, with very good agreement with experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071397j [article] Cubic two-state equation of state for associating fluids [texte imprimé] / Milton Medeiros, Auteur ; Pablo Téllez-Arredondo, Auteur . - 2008 . - p. 5723-5733. Bibliogr. p. 5732-5733 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5723-5733 Mots-clés : Two-state association model  Equation of state Résumé : The Kontogeorgis’ approach (CPA; Ind. Eng. Chem. Res. 1996, 35, 4310) was employed for the extension of the Soave−Redlich-Kwong (SRK) equation to associating systems. The two-state association model (TSAM) of Cerdeiriña et al. (J. Chem. Phys. 2004, 120, 6648) was modified and employed for describing the association contribution. The modification of TSAM consisted of developing an expression for the association contribution for the Helmholtz free energy as an explicit function of temperature and density, on the basis of the two-state approach. Similar to the CPA equation, the resulting cubic two-state (CTS) equation of state (EoS) has five parameters, three of them related to the nonspecific (physical) contribution and the other two related to the association. The CTS EoS is polynomial in volume and preserves the shape of a cubic equation in the region of positive volumes greater than the covolume, having one or three roots in this zone. For pure substances the equation is quartic, and it has analytical solution. The equation was fit to experimental vapor pressure and liquid density data of water, alcohols, and phenols, with very low deviations. The model was also employed to predict second virial coefficients of pure compounds, and phase equilibria of alcohol-alkane mixtures, using conventional mixing rules and one binary parameter, with very good agreement with experimental data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071397j

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Polymerization of n-vinylcarbazole in supercritical carbon dioxide and in a supercritical region of a carbon dioxide and dimethyl ether mixture / Kyung Shil Oh in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5734-5741 Titre : Polymerization of n-vinylcarbazole in supercritical carbon dioxide and in a supercritical region of a carbon dioxide and dimethyl ether mixture Type de document : texte imprimé Auteurs : Kyung Shil Oh, Auteur ; Won Bae, Auteur ; Youn Woo Lee, Auteur ; Hwayong Kim, Auteur Année de publication : 2008 Article en page(s) : p. 5734-5741 Note générale : Bibliogr. p. 5740-5741 Langues : Anglais (eng) Mots-clés : N-vinylcarbazole -- polimerization  Carbon dioxide  Fluorine-based Résumé : Spherical poly(N-vinylcarbazole) (PVK) particles were synthesized by polymerization of N-vinylcarbazole (NVCA) in supercritical carbon dioxide (scCO2) and a supercritical region of a CO2 and dimethyl ether (DME) mixture using a fluorine-based [poly(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl methacrylate)] [poly(HDFDMA)] polymer as the surfactant and 2,2′-azobisisobutyronitrile (AIBN) as the initiator. The spherical PVK particles could be consistently produced under the given experimental conditions. The PVK particle size showed a bimodal distribution when scCO2 was used as solvent. Therefore DME was added to the system as a cosolvent. The resulting particle size was shown to be dependent on the amount of surfactant and DME added to the system. As the ratio of DME increased, the average molecular mass of the PVK particles decreased. The effects of surfactant and initiator concentrations were investigated with respect to the morphology, size, and molecular mass of the PVK particles. The effects of the addition of a mixed solvent consisting of CO2 + DME on polymeric particle morphology, size, and molecular mass of polymers were also studied and are discussed herein. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071526w [article] Polymerization of n-vinylcarbazole in supercritical carbon dioxide and in a supercritical region of a carbon dioxide and dimethyl ether mixture [texte imprimé] / Kyung Shil Oh, Auteur ; Won Bae, Auteur ; Youn Woo Lee, Auteur ; Hwayong Kim, Auteur . - 2008 . - p. 5734-5741. Bibliogr. p. 5740-5741 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5734-5741 Mots-clés : N-vinylcarbazole -- polimerization  Carbon dioxide  Fluorine-based Résumé : Spherical poly(N-vinylcarbazole) (PVK) particles were synthesized by polymerization of N-vinylcarbazole (NVCA) in supercritical carbon dioxide (scCO2) and a supercritical region of a CO2 and dimethyl ether (DME) mixture using a fluorine-based [poly(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyl methacrylate)] [poly(HDFDMA)] polymer as the surfactant and 2,2′-azobisisobutyronitrile (AIBN) as the initiator. The spherical PVK particles could be consistently produced under the given experimental conditions. The PVK particle size showed a bimodal distribution when scCO2 was used as solvent. Therefore DME was added to the system as a cosolvent. The resulting particle size was shown to be dependent on the amount of surfactant and DME added to the system. As the ratio of DME increased, the average molecular mass of the PVK particles decreased. The effects of surfactant and initiator concentrations were investigated with respect to the morphology, size, and molecular mass of the PVK particles. The effects of the addition of a mixed solvent consisting of CO2 + DME on polymeric particle morphology, size, and molecular mass of polymers were also studied and are discussed herein. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071526w

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Studies relating to cathodic reactions in neutral chloride solutions used in chlorate processes / Subramanyan Vasudevan in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5742–5745 Titre : Studies relating to cathodic reactions in neutral chloride solutions used in chlorate processes Type de document : texte imprimé Auteurs : Subramanyan Vasudevan, Auteur Année de publication : 2008 Article en page(s) : p. 5742–5745 Note générale : Bibliogr. p. 5745 Langues : Anglais (eng) Mots-clés : Neutral alkali -- cathodic reactions  Hydroxide precipitation Résumé : The present work has been conducted to elucidate on the cathodic reactions in neutral alkali and alkaline-earth metal chloride solutions. The experiments were carried out on platinum anode in neutral chloride solutions of sodium, potassium, magnesium, strontium, and barium (electrolyte for chlorate process) by means of steady-state E-log i curves. The results indicate that the cathodic hydrogen evolutions in sodium and potassium chloride electrolyte yield similar curves. The cathodic hydrogen evolution reaction in magnesium, strontium, and barium chloride electrolytes takes place at more negative potentials (about 120-150 mv) than that in sodium and potassium chloride. This is due to the difference in local pH and hydroxide precipitation near the cathode surface. The hydroxide precipitation on the cathode surface in the case of alkaline earth metal salts was overcome by the rotation of cathode at 1.38 m s-1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800038f [article] Studies relating to cathodic reactions in neutral chloride solutions used in chlorate processes [texte imprimé] / Subramanyan Vasudevan, Auteur . - 2008 . - p. 5742–5745. Bibliogr. p. 5745 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5742–5745 Mots-clés : Neutral alkali -- cathodic reactions  Hydroxide precipitation Résumé : The present work has been conducted to elucidate on the cathodic reactions in neutral alkali and alkaline-earth metal chloride solutions. The experiments were carried out on platinum anode in neutral chloride solutions of sodium, potassium, magnesium, strontium, and barium (electrolyte for chlorate process) by means of steady-state E-log i curves. The results indicate that the cathodic hydrogen evolutions in sodium and potassium chloride electrolyte yield similar curves. The cathodic hydrogen evolution reaction in magnesium, strontium, and barium chloride electrolytes takes place at more negative potentials (about 120-150 mv) than that in sodium and potassium chloride. This is due to the difference in local pH and hydroxide precipitation near the cathode surface. The hydroxide precipitation on the cathode surface in the case of alkaline earth metal salts was overcome by the rotation of cathode at 1.38 m s-1. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800038f

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Preparation of layered double hydroxide microspheres by spray drying / Yanchang Wang in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5746–5750 Titre : Preparation of layered double hydroxide microspheres by spray drying Type de document : texte imprimé Auteurs : Yanchang Wang, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur ; Xiaoying Wang, Auteur Année de publication : 2008 Article en page(s) : p. 5746–5750 Note générale : Bibliogr. p. 5749-5750 Langues : Anglais (eng) Mots-clés : Layered double hydroxide materials  Separate nucleation  Spray drying Résumé : In order to fully exploit their attractive properties in actual practical applications, layered double hydroxide (LDH) materials should be fabricated into macroscopic form. A magnesium−aluminum layered double hydroxide (MgAl-LDH) containing interlayer carbonate anions has been obtained using a synthesis route involving separate nucleation and aging steps, and microspheres of the material formed in a subsequent spray drying process. The resulting products are composed of nanosized LDH particles aggregated into solid microspheres with a diameter of 10-50 μm, a sphericity of 0.84, modal pore access diameter of 87.9 nm, surface area of 43 m2/g, and total pore volume of 1.29 cm3/g. The presence of an accessible diffusion pathway in the macropore domain of the LDH microspheres offers the possibility of enhanced performances in a wide range of applications. Furthermore, the spherical morphology of the materials was retained when the LDHs were converted into solid base catalysts by calcination and subsequent rehydration, indicating the robust nature of the macroscopic particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800146m [article] Preparation of layered double hydroxide microspheres by spray drying [texte imprimé] / Yanchang Wang, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur ; Xiaoying Wang, Auteur . - 2008 . - p. 5746–5750. Bibliogr. p. 5749-5750 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5746–5750 Mots-clés : Layered double hydroxide materials  Separate nucleation  Spray drying Résumé : In order to fully exploit their attractive properties in actual practical applications, layered double hydroxide (LDH) materials should be fabricated into macroscopic form. A magnesium−aluminum layered double hydroxide (MgAl-LDH) containing interlayer carbonate anions has been obtained using a synthesis route involving separate nucleation and aging steps, and microspheres of the material formed in a subsequent spray drying process. The resulting products are composed of nanosized LDH particles aggregated into solid microspheres with a diameter of 10-50 μm, a sphericity of 0.84, modal pore access diameter of 87.9 nm, surface area of 43 m2/g, and total pore volume of 1.29 cm3/g. The presence of an accessible diffusion pathway in the macropore domain of the LDH microspheres offers the possibility of enhanced performances in a wide range of applications. Furthermore, the spherical morphology of the materials was retained when the LDHs were converted into solid base catalysts by calcination and subsequent rehydration, indicating the robust nature of the macroscopic particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800146m

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A group contribution method for heat capacity estimation of ionic liquids / Ramesh L. Gardas in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5751–5757 Titre : A group contribution method for heat capacity estimation of ionic liquids Type de document : texte imprimé Auteurs : Ramesh L. Gardas, Auteur ; João A.P. Coutinho, Auteur Année de publication : 2008 Article en page(s) : p. 5751–5757 Note générale : Bibliogr. p. 5756-5757 Langues : Anglais (eng) Mots-clés : Ionic liquids  Liquid heat capacity  Correlation Résumé : Based on experimental liquid heat capacity (CpL) data collected from the literature, a second-order group additivity method has been developed for the estimation of the liquid heat capacity of imidazolium-, pyridinium-, and pyrrolidinium-based ionic liquids (ILs) containing hexafluorophosphate (PF6), tetrafluoroborate (BF4), bis(trifluoromethanesulfonyl) amide (Tf2N), bromide (Br), ethyl sulfate (EtSO4), or trifluoromethane sulfonate (CF3SO3) as anions, covering wide ranges of temperature (196.36−663.10 K) and liquid heat capacity (264.8−825.0 J mol−1 K−1). It is shown that a good description of the literature data is obtained with the proposed method. For ca. 2400 data points from 19 ILs that have been studied, a mean percent deviation (MPD) of 0.36% with a maximum deviation of 2%. A correlation of heat capacities with molar volumes of the ILs was also developed for the estimation of heat capacity at 298.15 K. Therefore, the group contribution method developed here can be used to evaluate the liquid heat capacity of new ILs and, as data for new groups of cations and anions become available, can be extended to a larger range of ionic liquids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800330v [article] A group contribution method for heat capacity estimation of ionic liquids [texte imprimé] / Ramesh L. Gardas, Auteur ; João A.P. Coutinho, Auteur . - 2008 . - p. 5751–5757. Bibliogr. p. 5756-5757 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5751–5757 Mots-clés : Ionic liquids  Liquid heat capacity  Correlation Résumé : Based on experimental liquid heat capacity (CpL) data collected from the literature, a second-order group additivity method has been developed for the estimation of the liquid heat capacity of imidazolium-, pyridinium-, and pyrrolidinium-based ionic liquids (ILs) containing hexafluorophosphate (PF6), tetrafluoroborate (BF4), bis(trifluoromethanesulfonyl) amide (Tf2N), bromide (Br), ethyl sulfate (EtSO4), or trifluoromethane sulfonate (CF3SO3) as anions, covering wide ranges of temperature (196.36−663.10 K) and liquid heat capacity (264.8−825.0 J mol−1 K−1). It is shown that a good description of the literature data is obtained with the proposed method. For ca. 2400 data points from 19 ILs that have been studied, a mean percent deviation (MPD) of 0.36% with a maximum deviation of 2%. A correlation of heat capacities with molar volumes of the ILs was also developed for the estimation of heat capacity at 298.15 K. Therefore, the group contribution method developed here can be used to evaluate the liquid heat capacity of new ILs and, as data for new groups of cations and anions become available, can be extended to a larger range of ionic liquids. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800330v

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A new reference state for the calculation of activity coefficients / Jaime Wisniak in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5758–5760 Titre : A new reference state for the calculation of activity coefficients : comment on the paper “a molecular theory of the activity coefficient and their reference fugacities at the supercritical state” Type de document : texte imprimé Auteurs : Jaime Wisniak, Auteur ; Hugo Segura, Auteur Année de publication : 2008 Article en page(s) : p. 5758–5760 Note générale : Bibliogr. p. 5760 Langues : Anglais (eng) Note de contenu : Correspondance En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006566 [article] A new reference state for the calculation of activity coefficients : comment on the paper “a molecular theory of the activity coefficient and their reference fugacities at the supercritical state” [texte imprimé] / Jaime Wisniak, Auteur ; Hugo Segura, Auteur . - 2008 . - p. 5758–5760. Bibliogr. p. 5760 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5758–5760 Note de contenu : Correspondance En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8006566

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