Catalogue en ligne Bibliothèque Ecole Nationale Polytechnique d'Alger

[article]
in Industrial & 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]
in Industrial & 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 <2.5% was observed. From the total data points of estimated heat capacities, 90.2% present deviations of <1% from the experimental values, whereas only 0.9% have deviations 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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 analysis; 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]
in Industrial & 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]
in Industrial & 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 theory; 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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 equation;
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]
in Industrial & 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]
in Industrial & 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 (<1 atm). Adsorption isotherms for CO2 in Mn+-SAPO-34 materials displayed a nonlinear behavior and did not follow the typical pore-filling mechanism. In general, the overall adsorption performance of the exchanged materials increased as follows: Ce3+ < Ti3+ < Mg2+ < Ca2+ < Ag+ < Na+ < Sr2+. The strontium exchanged materials excelled at low-pressure ranges, exhibiting very sharp isotherm slopes at all temperatures. For example, the Sr2+-SAPO-34 sorbents were capable of removing as much as 2.8 wt % at a CO2 partial pressure of 10−3 atm and room temperature. Isosteric heat of adsorption data confirmed that the Sr2+ species were responsible for the surface strong interaction, and therefore it is plausible to state that cations were occupying exposed sites (SII′) in the material Chabazite cages. In addition, all divalent cations were found to interact more with the sorbate when compared to the other charged species. Adsorption isotherms for trivalent exchanged cations (Ce3+, Ti3+), on the other hand, showed what appears to be partial blockage of pore windows (occupancy of SIII), resulting in very low adsorption capacities. The surface interactions were analyzed according to electrostatic and nonspecific contributions. Due to strong ion−quadrupole interactions, all the sorbent materials exhibited higher affinity for CO2 over the other gases tested (i.e., CH4, H2, N2, and O2). Mathematical modeling to estimate binary component adsorption performance during vacuum pressure adsorption (VPSA) corroborated that Sr2+-SAPO-34 sorbents are by far the best option for CO2 removal from CH4 mixtures, especially at low concentrations.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie071309v

[article]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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; Nonlinear 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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; API -- engineering performance properties; 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]
in Industrial & 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 coefficients; 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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 acid; 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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 production; 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]
in Industrial & 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]
in Industrial & 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; Protein−protein interactions -- 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]
in Industrial & 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]
in Industrial & 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 acids; 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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 equilibrium; 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]
in Industrial & 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]
in Industrial & 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 equilibria; Propane + diamantane system; Ethane + diamantane 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]
in Industrial & 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]
in Industrial & 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 < 0.
En ligne :	http://pubs.acs.org/doi/abs/10.1021/ie0712277

[article]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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 of 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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 aqueous solutes
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]
in Industrial & 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 mixtures -- 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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]
in Industrial & 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

Industrial & engineering chemistry research / Paul, Donald R. . Vol. 47 n°15

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