Dépouillements

Polymer blends in membrane transport processes / Lloyd M. Robeson in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11859-11865 Titre : Polymer blends in membrane transport processes Type de document : texte imprimé Auteurs : Lloyd M. Robeson, Auteur Année de publication : 2011 Article en page(s) : pp. 11859-11865 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Transport process Membrane transport Polymer blends Résumé : Polymer blend technology and gas membrane separation have been two research areas where Prof. Don Paul has had major contributions. The combination of these topics has been chosen as the subject of this review paper. The morphology of phase separated polymer blends is an important variable in the design of enhanced transport properties. The fundamentals of polymer blends in transport processes will be discussed along with situations where polymer blends may be desired. These areas include barrier polymers, gas membrane separation, percolation networks for electrical conductivity, proton exchange membranes, and polymers employed in optociectronic devices. The predictions of the series, parallel, Maxwell, and equivalent box models are applied where relevant to these examples. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463341 [article] Polymer blends in membrane transport processes [texte imprimé] / Lloyd M. Robeson, Auteur . - 2011 . - pp. 11859-11865. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11859-11865 Mots-clés : Transport process Membrane transport Polymer blends Résumé : Polymer blend technology and gas membrane separation have been two research areas where Prof. Don Paul has had major contributions. The combination of these topics has been chosen as the subject of this review paper. The morphology of phase separated polymer blends is an important variable in the design of enhanced transport properties. The fundamentals of polymer blends in transport processes will be discussed along with situations where polymer blends may be desired. These areas include barrier polymers, gas membrane separation, percolation networks for electrical conductivity, proton exchange membranes, and polymers employed in optociectronic devices. The predictions of the series, parallel, Maxwell, and equivalent box models are applied where relevant to these examples. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463341

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Role of nanocomposite hydrogel morphology in the electrophoretic separation of biomolecules / Jyothirmai J. Simhadri in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11866–11877 Titre : Role of nanocomposite hydrogel morphology in the electrophoretic separation of biomolecules : a review Type de document : texte imprimé Auteurs : Jyothirmai J. Simhadri, Auteur ; Holly A. Stretz, Auteur ; Mario Oyanader, Auteur Année de publication : 2011 Article en page(s) : pp. 11866–11877 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanocomposite hydrogel Electrophoretic Résumé : Hydrogels are widely used to produce biomolecular separations in electrophoretic applications, where gel morphology and charge effects combine to produce the separation. Nanocomposite gels are poised to revolutionize this field in both improved handling characteristics and improved separations. Gel morphology and charge effects have traditionally been manipulated by varying the copolymer composition, but recent reports show that novel morphological changes can also be induced in the gel using templating methods and nanoparticle addition. To aid realization of the potential for novel electrically driven separations arising from such novel morphologies, we review here advances in materials development alongside a review of the directions in biomolecule/hydrogel electrophoretic transport modeling. Models for polyelectrolyte transport that are potentially useful for understanding novel behaviors caused by gel morphology are analyzed first. With the perspective of theoretical guidance, we then survey nanocomposite hydrogel morphologies keyed by the nanoparticle and matrix. Finally, we survey as well reports of dramatic improvements in the mechanical properties that may be the key to the early adoption of these new materials in biomolecular separation applications. For modeling, we have identified the different scales involved in biomolecular transport in these materials and provided a taxonomy of transport models that emphasize the role of gel morphology in determining both polyelectrolyte mobility and diffusion. Three aspects for future work unique to nanocomposite gel materials are described: (a) descriptions of the distribution of nanoparticles within the gels; (b) descriptions of the motion of the buffer solution that may include electroosmotic effects for nanoparticles with surface charges; (c) descriptions of the motion of the polyelectrolyte molecule inside the new gel material for a given application. These aspects will help to uncover further quantitative details about the ability of these gels to be tunable for differential mass transport of a given type of molecule. Standard gels, currently, lack a broad flexibility to increase the separation of biomolecules and, in general, are not tunable. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003762 [article] Role of nanocomposite hydrogel morphology in the electrophoretic separation of biomolecules : a review [texte imprimé] / Jyothirmai J. Simhadri, Auteur ; Holly A. Stretz, Auteur ; Mario Oyanader, Auteur . - 2011 . - pp. 11866–11877. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11866–11877 Mots-clés : Nanocomposite hydrogel Electrophoretic Résumé : Hydrogels are widely used to produce biomolecular separations in electrophoretic applications, where gel morphology and charge effects combine to produce the separation. Nanocomposite gels are poised to revolutionize this field in both improved handling characteristics and improved separations. Gel morphology and charge effects have traditionally been manipulated by varying the copolymer composition, but recent reports show that novel morphological changes can also be induced in the gel using templating methods and nanoparticle addition. To aid realization of the potential for novel electrically driven separations arising from such novel morphologies, we review here advances in materials development alongside a review of the directions in biomolecule/hydrogel electrophoretic transport modeling. Models for polyelectrolyte transport that are potentially useful for understanding novel behaviors caused by gel morphology are analyzed first. With the perspective of theoretical guidance, we then survey nanocomposite hydrogel morphologies keyed by the nanoparticle and matrix. Finally, we survey as well reports of dramatic improvements in the mechanical properties that may be the key to the early adoption of these new materials in biomolecular separation applications. For modeling, we have identified the different scales involved in biomolecular transport in these materials and provided a taxonomy of transport models that emphasize the role of gel morphology in determining both polyelectrolyte mobility and diffusion. Three aspects for future work unique to nanocomposite gel materials are described: (a) descriptions of the distribution of nanoparticles within the gels; (b) descriptions of the motion of the buffer solution that may include electroosmotic effects for nanoparticles with surface charges; (c) descriptions of the motion of the polyelectrolyte molecule inside the new gel material for a given application. These aspects will help to uncover further quantitative details about the ability of these gels to be tunable for differential mass transport of a given type of molecule. Standard gels, currently, lack a broad flexibility to increase the separation of biomolecules and, in general, are not tunable. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003762

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Supersaturation control and heterogeneous nucleation in membrane crystallizers / Gianluca Di Profio in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.11878–11889 Titre : Supersaturation control and heterogeneous nucleation in membrane crystallizers : facts and perspectives Type de document : texte imprimé Auteurs : Gianluca Di Profio, Auteur ; Efrem Curcio, Auteur ; Enrico Drioli, Auteur Année de publication : 2011 Article en page(s) : pp.11878–11889 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heterogeneous nucleation Membrane crystallizers Résumé : The interest to combine membrane operations and solution crystallization has grown in the past several years. This approach has been put into practice in several forms of membrane-assisted crystallization (MAC) processes, among which is membrane crystallization (MCr) technology. The main features of MCr are (1) the use of membranes as precision devices to control the composition of the crystallizing solution, by opposing a well-defined and tunable resistance to mass flow occurring in the vapor phase; (2) the action of the porous surface of the membrane as a suitable support to activate heterogeneous nucleation mechanisms; (3) the possibility to induce nucleation and crystal growth in separate sites, thus reducing the risk of membrane fouling even when the same membrane supports heterogeneous nucleation. Thanks to these fundamental options, combined together in a unique apparatus, advantages like (i) improved control of the supersaturation degree and the rate of its generation; (ii) the possibility for the crystallization to be initiated at low supersaturation levels; (iii) the enhancement of the crystallization kinetics; and (iv) improved overall process efficiency can be achieved, even for large and complex molecules like proteins. The most interesting developments and the more exciting perspectives for this novel technology have been reviewed in this paper. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100418z [article] Supersaturation control and heterogeneous nucleation in membrane crystallizers : facts and perspectives [texte imprimé] / Gianluca Di Profio, Auteur ; Efrem Curcio, Auteur ; Enrico Drioli, Auteur . - 2011 . - pp.11878–11889. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.11878–11889 Mots-clés : Heterogeneous nucleation Membrane crystallizers Résumé : The interest to combine membrane operations and solution crystallization has grown in the past several years. This approach has been put into practice in several forms of membrane-assisted crystallization (MAC) processes, among which is membrane crystallization (MCr) technology. The main features of MCr are (1) the use of membranes as precision devices to control the composition of the crystallizing solution, by opposing a well-defined and tunable resistance to mass flow occurring in the vapor phase; (2) the action of the porous surface of the membrane as a suitable support to activate heterogeneous nucleation mechanisms; (3) the possibility to induce nucleation and crystal growth in separate sites, thus reducing the risk of membrane fouling even when the same membrane supports heterogeneous nucleation. Thanks to these fundamental options, combined together in a unique apparatus, advantages like (i) improved control of the supersaturation degree and the rate of its generation; (ii) the possibility for the crystallization to be initiated at low supersaturation levels; (iii) the enhancement of the crystallization kinetics; and (iv) improved overall process efficiency can be achieved, even for large and complex molecules like proteins. The most interesting developments and the more exciting perspectives for this novel technology have been reviewed in this paper. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100418z

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Irreversible anionic polymerization kinetics revisited / Isaac C. Sanchez in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11890–11895 Titre : Irreversible anionic polymerization kinetics revisited Type de document : texte imprimé Auteurs : Isaac C. Sanchez, Auteur Année de publication : 2011 Article en page(s) : pp. 11890–11895 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymerization Kinetics Résumé : Irreversible anionic polymerization is revisited with an emphasis on determining the dependence of the MW distribution on initial conditions. It is shown that only two parameters govern the distribution: the ratio of initiation to propagation rate constants and the ratio of initial monomer to initiator concentrations. New and simple criteria are developed that predict the breadth of the MW distribution based on these parameters. Even when initiation is slower than propagation, it is still possible under certain conditions to obtain a narrow, Poisson-like MW distribution. Since it impacts self-assembly of block copolymers into microphases, the compositional variation of block copolymers produced by living polymerization techniques is also analyzed. A somewhat unexpected result is the composition variability in block copolymers can be significant (10−15%) even when the blocks have dispersity indices less than 1.01. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003637 [article] Irreversible anionic polymerization kinetics revisited [texte imprimé] / Isaac C. Sanchez, Auteur . - 2011 . - pp. 11890–11895. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11890–11895 Mots-clés : Polymerization Kinetics Résumé : Irreversible anionic polymerization is revisited with an emphasis on determining the dependence of the MW distribution on initial conditions. It is shown that only two parameters govern the distribution: the ratio of initiation to propagation rate constants and the ratio of initial monomer to initiator concentrations. New and simple criteria are developed that predict the breadth of the MW distribution based on these parameters. Even when initiation is slower than propagation, it is still possible under certain conditions to obtain a narrow, Poisson-like MW distribution. Since it impacts self-assembly of block copolymers into microphases, the compositional variation of block copolymers produced by living polymerization techniques is also analyzed. A somewhat unexpected result is the composition variability in block copolymers can be significant (10−15%) even when the blocks have dispersity indices less than 1.01. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1003637

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One - step melt extrusion process for preparing polyolefin/clay nanocomposites using natural montmorillonite / Benjamin F. Ports in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11896–11905 Titre : One - step melt extrusion process for preparing polyolefin/clay nanocomposites using natural montmorillonite Type de document : texte imprimé Auteurs : Benjamin F. Ports, Auteur ; R. A. Weiss, Auteur Année de publication : 2011 Article en page(s) : pp. 11896–11905 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polyolefin Nanocomposites Sodium montmorillonite Résumé : Polyolefin/clay nanocomposites were fabricated by directly melt compounding poly(ethylene-co-ran-acrylic acid), PEAA, with sodium montmorillonite and a low molecular weight quaternary ammonium salt in a simple process where all the components were fed simultaneously to the extruder. The effects of processing conditions, salt structure, and concentration on the clay dispersion, morphology, and mechanical properties were investigated using X-ray diffraction, transmission electron microscopy, and dynamic mechanical testing. The one-step method was effective at simultaneously dispersing and intercalating/exfoliating the natural montmorillonite and produced nanocomposites comparable to those prepared by melt compounding the PEAA with commercial organoclay. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902050r [article] One - step melt extrusion process for preparing polyolefin/clay nanocomposites using natural montmorillonite [texte imprimé] / Benjamin F. Ports, Auteur ; R. A. Weiss, Auteur . - 2011 . - pp. 11896–11905. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11896–11905 Mots-clés : Polyolefin Nanocomposites Sodium montmorillonite Résumé : Polyolefin/clay nanocomposites were fabricated by directly melt compounding poly(ethylene-co-ran-acrylic acid), PEAA, with sodium montmorillonite and a low molecular weight quaternary ammonium salt in a simple process where all the components were fed simultaneously to the extruder. The effects of processing conditions, salt structure, and concentration on the clay dispersion, morphology, and mechanical properties were investigated using X-ray diffraction, transmission electron microscopy, and dynamic mechanical testing. The one-step method was effective at simultaneously dispersing and intercalating/exfoliating the natural montmorillonite and produced nanocomposites comparable to those prepared by melt compounding the PEAA with commercial organoclay. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie902050r

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Phase behavior of magnesium stearate blended with polyethylene ionomers / Katsuyuki Wakabayashi in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11906–11913 Titre : Phase behavior of magnesium stearate blended with polyethylene ionomers Type de document : texte imprimé Auteurs : Katsuyuki Wakabayashi, Auteur ; Richard A. Register, Auteur Année de publication : 2011 Article en page(s) : pp. 11906–11913 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Magnesium Polyethylene ionomers Résumé : The phase behavior in blends of magnesium salts of long-chain fatty acids with magnesium-neutralized ethylene-based ionomers is described. Anhydrous magnesium stearate and magnesium stearate−palmitate, collectively termed MgSt(Pm), show a common phase behavior, consisting of a crystalline lamellar mesophase (LAM) bilayer phase at low temperatures, a liquid crystalline hexagonal (HEX) phase at intermediate temperatures, and a molten disordered (DIS) phase at high temperatures. Once heated into the HEX or DIS phase, neat MgSt(Pm) is kinetically prevented from reforming the LAM phase upon cooling. Blending an ionomer into MgSt(Pm) destabilizes the HEX phase in favor of DIS; an intimately mixed DIS phase is formed above the LAM and ionomer melting points, where the ionomer acts as an effective solvent for the MgSt(Pm). Quenching this solution forms co-crystals that incorporate alkyl tails from the fatty acid salt and ethylene sequences from the ionomer. Heating the blend to below the LAM melting point melts the co-crystals and allows pure, well-ordered LAM MgSt(Pm) to crystallize from the solution. A generalized phase diagram for MgSt blended with ionomers is presented to describe the observed behavior. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100109e [article] Phase behavior of magnesium stearate blended with polyethylene ionomers [texte imprimé] / Katsuyuki Wakabayashi, Auteur ; Richard A. Register, Auteur . - 2011 . - pp. 11906–11913. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11906–11913 Mots-clés : Magnesium Polyethylene ionomers Résumé : The phase behavior in blends of magnesium salts of long-chain fatty acids with magnesium-neutralized ethylene-based ionomers is described. Anhydrous magnesium stearate and magnesium stearate−palmitate, collectively termed MgSt(Pm), show a common phase behavior, consisting of a crystalline lamellar mesophase (LAM) bilayer phase at low temperatures, a liquid crystalline hexagonal (HEX) phase at intermediate temperatures, and a molten disordered (DIS) phase at high temperatures. Once heated into the HEX or DIS phase, neat MgSt(Pm) is kinetically prevented from reforming the LAM phase upon cooling. Blending an ionomer into MgSt(Pm) destabilizes the HEX phase in favor of DIS; an intimately mixed DIS phase is formed above the LAM and ionomer melting points, where the ionomer acts as an effective solvent for the MgSt(Pm). Quenching this solution forms co-crystals that incorporate alkyl tails from the fatty acid salt and ethylene sequences from the ionomer. Heating the blend to below the LAM melting point melts the co-crystals and allows pure, well-ordered LAM MgSt(Pm) to crystallize from the solution. A generalized phase diagram for MgSt blended with ionomers is presented to describe the observed behavior. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100109e

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High water vapor flun membranes based on novel diol − imidazolium polymers / Andrew L. LaFrate in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11914–11919 Titre : High water vapor flun membranes based on novel diol − imidazolium polymers Type de document : texte imprimé Auteurs : Andrew L. LaFrate, Auteur ; Douglas L. Gin, Auteur ; Richard D. Noble, Auteur Année de publication : 2011 Article en page(s) : pp. 11914–11919 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymers Résumé : A breathable membrane that demonstrates high water vapor flux was prepared using a diol-functionalized polymerizable room temperature ionic liquid. A novel monomer material was synthesized and used to fabricate thin films which were tested for their ability to transport water vapor. These materials were tested beside commercial breathable polymers for comparison. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100227h [article] High water vapor flun membranes based on novel diol − imidazolium polymers [texte imprimé] / Andrew L. LaFrate, Auteur ; Douglas L. Gin, Auteur ; Richard D. Noble, Auteur . - 2011 . - pp. 11914–11919. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11914–11919 Mots-clés : Polymers Résumé : A breathable membrane that demonstrates high water vapor flux was prepared using a diol-functionalized polymerizable room temperature ionic liquid. A novel monomer material was synthesized and used to fabricate thin films which were tested for their ability to transport water vapor. These materials were tested beside commercial breathable polymers for comparison. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100227h

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Gas and vapor transport in mixed matrix membranes based on amorphous teflon AF1600 and AF2400 and fumed silica / M. C. Ferrari in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11920–11935 Titre : Gas and vapor transport in mixed matrix membranes based on amorphous teflon AF1600 and AF2400 and fumed silica Type de document : texte imprimé Auteurs : M. C. Ferrari, Auteur ; M. Galizia, Auteur ; M. G. De Angelis, Auteur Année de publication : 2011 Article en page(s) : pp. 11920–11935 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Vapor Résumé : The enhancement of gas and vapor transport rates induced by the addition of fumed silica nanoparticles to fluorinated glassy polymers is interpreted and quantitatively modeled considering the additional free volume created by incorporation of filler. That effect can be evaluated accurately from gas solubility data, using the NELF model. The solubility of CH4 and CO2 in matrices of Teflon AF1600 and AF2400, filled with variable amounts of fumed silica nanoparticles, was measured at 35 °C; the solubility of n-C4 and n-C5 vapors, as well as their diffusivity and the dilation induced in the same polymer matrices, was also measured at 25 °C. The fractional free volume (FFV) values, estimated on the basis of CH4 solubility data, were used to predict the solubility of the other penetrants inspected, with excellent agreement with experimental data. In addition, a single empirical correlation can be drawn, for both AF1600 and AF2400-based mixed matrices, between the infinite dilution diffusivity of vapors and the FFV value calculated from solubility data. Similarly, a simple correlation valid for both matrices is obtained as well for the dependence of diffusivity on penetrant concentration. Finally, use of the NELF model also allows an estimate of the swelling induced by the sorption process on the basis of virtually one simple data point of gas solubility. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100242q [article] Gas and vapor transport in mixed matrix membranes based on amorphous teflon AF1600 and AF2400 and fumed silica [texte imprimé] / M. C. Ferrari, Auteur ; M. Galizia, Auteur ; M. G. De Angelis, Auteur . - 2011 . - pp. 11920–11935. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11920–11935 Mots-clés : Gas Vapor Résumé : The enhancement of gas and vapor transport rates induced by the addition of fumed silica nanoparticles to fluorinated glassy polymers is interpreted and quantitatively modeled considering the additional free volume created by incorporation of filler. That effect can be evaluated accurately from gas solubility data, using the NELF model. The solubility of CH4 and CO2 in matrices of Teflon AF1600 and AF2400, filled with variable amounts of fumed silica nanoparticles, was measured at 35 °C; the solubility of n-C4 and n-C5 vapors, as well as their diffusivity and the dilation induced in the same polymer matrices, was also measured at 25 °C. The fractional free volume (FFV) values, estimated on the basis of CH4 solubility data, were used to predict the solubility of the other penetrants inspected, with excellent agreement with experimental data. In addition, a single empirical correlation can be drawn, for both AF1600 and AF2400-based mixed matrices, between the infinite dilution diffusivity of vapors and the FFV value calculated from solubility data. Similarly, a simple correlation valid for both matrices is obtained as well for the dependence of diffusivity on penetrant concentration. Finally, use of the NELF model also allows an estimate of the swelling induced by the sorption process on the basis of virtually one simple data point of gas solubility. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100242q

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Helical crystal assemblies in nonracemic chiral liquid crystalline polymers / Jing Wang in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11936–11947 Titre : Helical crystal assemblies in nonracemic chiral liquid crystalline polymers : where chemistry and physics meet Type de document : texte imprimé Auteurs : Jing Wang, Auteur ; Christopher Y. Li, Auteur ; Shi Jin, Auteur Année de publication : 2011 Article en page(s) : pp. 11936–11947 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Liquid Crystalline Polymers Résumé : Chirality transfer (or amplification) in soft materials is an important topic for understanding how chiral assemblies develop from the atomic level to macroscopic objects. This is an interdisciplinary area which is critically associated with the evolution from asymmetric chemistry to asymmetric physics, and, more specifically, in biomaterials, liquid crystals, and polymers. In this review, we discuss our recent studies on the conditions for chirality transfer across different length scales. We observed that the formation of helical structures in different length scales is a typical process in chirality transfer. This is illustrated by a series of nonracemic chiral main-chain liquid crystalline (LC) polyesters, PETs(R*-n). The polymers contained a different number of methylene units in the chain backbone (from 7 to 11). All of the PETs(R*-n) macroscopically exhibited an LC chiral smectic C (SC*) phase, a chiral smectic A (SA*) phase, and a twist grain boundary smectic A (TGBA*) phase with increasing temperature. The atomic chiral centers caused the helical conformation, and then, helical lamellar crystals were found in these polymers. The crystal structures were determined by X-ray diffraction and electron diffraction techniques. Dark field transmission electron microscopic images revealed that the molecular orientation in these helical crystals is double twisted. Our systematic studies showed that chirality transfer from one length scale to another is neither automatic, nor necessary, and it critically depends upon the packing scheme of the chiral building blocks on each length scale. It was particularly surprising that in this series of polyesters, the odd−even effect exists across many length scales. This includes not only thermodynamic properties such as the SC*, the SA*, and the TGBA* LC phase transition temperatures, but also the helical crystal handedness. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100248r#afn1 [article] Helical crystal assemblies in nonracemic chiral liquid crystalline polymers : where chemistry and physics meet [texte imprimé] / Jing Wang, Auteur ; Christopher Y. Li, Auteur ; Shi Jin, Auteur . - 2011 . - pp. 11936–11947. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11936–11947 Mots-clés : Liquid Crystalline Polymers Résumé : Chirality transfer (or amplification) in soft materials is an important topic for understanding how chiral assemblies develop from the atomic level to macroscopic objects. This is an interdisciplinary area which is critically associated with the evolution from asymmetric chemistry to asymmetric physics, and, more specifically, in biomaterials, liquid crystals, and polymers. In this review, we discuss our recent studies on the conditions for chirality transfer across different length scales. We observed that the formation of helical structures in different length scales is a typical process in chirality transfer. This is illustrated by a series of nonracemic chiral main-chain liquid crystalline (LC) polyesters, PETs(R*-n). The polymers contained a different number of methylene units in the chain backbone (from 7 to 11). All of the PETs(R*-n) macroscopically exhibited an LC chiral smectic C (SC*) phase, a chiral smectic A (SA*) phase, and a twist grain boundary smectic A (TGBA*) phase with increasing temperature. The atomic chiral centers caused the helical conformation, and then, helical lamellar crystals were found in these polymers. The crystal structures were determined by X-ray diffraction and electron diffraction techniques. Dark field transmission electron microscopic images revealed that the molecular orientation in these helical crystals is double twisted. Our systematic studies showed that chirality transfer from one length scale to another is neither automatic, nor necessary, and it critically depends upon the packing scheme of the chiral building blocks on each length scale. It was particularly surprising that in this series of polyesters, the odd−even effect exists across many length scales. This includes not only thermodynamic properties such as the SC*, the SA*, and the TGBA* LC phase transition temperatures, but also the helical crystal handedness. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100248r#afn1

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Gas transport properties of some fluorine - containing polyethers / J. C. Ignacio Lara-Estevez in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11948–11953 Titre : Gas transport properties of some fluorine - containing polyethers Type de document : texte imprimé Auteurs : J. C. Ignacio Lara-Estevez, Auteur ; Claudia Camacho-Zuniga, Auteur ; F. Alberto Ruiz-Trevino, Auteur Année de publication : 2011 Article en page(s) : pp. 11948–11953 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Polyethers Résumé : A set of five polyethers containing the highly fluorinated monomer, 1,3-bis(1,1,1,3,3,3-hexafluoro-2-pentafluorophenylmethoxy-2-propyl)benzene (12F-FBE), were obtained by polycondensation with the monomers: biphenol, bisphenol F, bisphenol A, bisphenol AF, and a biphenol-substituted spirodilactam. Significant physical properties to characterize their application as membranes for gas separations processes were measured. They exhibit little crystalline domains (below 8%), very similar cohesive energy densities (CED) (with differences smaller than 1.8 (cal/cm3)1/2), glass transition temperatures (Tg) above 94 °C, good thermal resistance (Td > 350 °C), low specific volumes (V ≤ 0.6516 cm3/g), and fractional free volumes (FFV) above 0.170. Their permeabilities, at 35 °C and 2 atm, to He, H2, O2, N2, CH4, and CO2 exceed those of commercial polysulfone (PSF) membranes. 12F-BISAF, the most permeable polyether with permeability coefficients (in Barrers) of 51 for He, 28 for H2, 3.8 for O2, and 12 for CO2, is also the material with the highest FFV. However, the observed relation between permeability and FFV confirms that besides FFV other features need to be taken into consideration to determine permeability—especially for the smaller permeants He and H2. Concerning the ideal selectivity factors of these materials, they are in the same order of magnitude as those of PSF. The material identified as 12F-SDL is the most selective member of this series with selectivity factors to H2/CH4, O2/N2, and CO2/CH4 of 84, 4.8, and 28, respectively. Such superior selectivity of 12F-SDL could be related mainly to inhibited segmental movements. These results are interpreted in terms of CED, FFV, and Tg together with their respective contribution of gas solubility and diffusivity to the overall selectivity coefficients. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100249j [article] Gas transport properties of some fluorine - containing polyethers [texte imprimé] / J. C. Ignacio Lara-Estevez, Auteur ; Claudia Camacho-Zuniga, Auteur ; F. Alberto Ruiz-Trevino, Auteur . - 2011 . - pp. 11948–11953. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11948–11953 Mots-clés : Gas Polyethers Résumé : A set of five polyethers containing the highly fluorinated monomer, 1,3-bis(1,1,1,3,3,3-hexafluoro-2-pentafluorophenylmethoxy-2-propyl)benzene (12F-FBE), were obtained by polycondensation with the monomers: biphenol, bisphenol F, bisphenol A, bisphenol AF, and a biphenol-substituted spirodilactam. Significant physical properties to characterize their application as membranes for gas separations processes were measured. They exhibit little crystalline domains (below 8%), very similar cohesive energy densities (CED) (with differences smaller than 1.8 (cal/cm3)1/2), glass transition temperatures (Tg) above 94 °C, good thermal resistance (Td > 350 °C), low specific volumes (V ≤ 0.6516 cm3/g), and fractional free volumes (FFV) above 0.170. Their permeabilities, at 35 °C and 2 atm, to He, H2, O2, N2, CH4, and CO2 exceed those of commercial polysulfone (PSF) membranes. 12F-BISAF, the most permeable polyether with permeability coefficients (in Barrers) of 51 for He, 28 for H2, 3.8 for O2, and 12 for CO2, is also the material with the highest FFV. However, the observed relation between permeability and FFV confirms that besides FFV other features need to be taken into consideration to determine permeability—especially for the smaller permeants He and H2. Concerning the ideal selectivity factors of these materials, they are in the same order of magnitude as those of PSF. The material identified as 12F-SDL is the most selective member of this series with selectivity factors to H2/CH4, O2/N2, and CO2/CH4 of 84, 4.8, and 28, respectively. Such superior selectivity of 12F-SDL could be related mainly to inhibited segmental movements. These results are interpreted in terms of CED, FFV, and Tg together with their respective contribution of gas solubility and diffusivity to the overall selectivity coefficients. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100249j

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Morphology and mechanical properties of nanocomposites fabricated from organoclays and a novolac phenolic resin via melt mixing / S. G. Kang in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11954–11960 Titre : Morphology and mechanical properties of nanocomposites fabricated from organoclays and a novolac phenolic resin via melt mixing Type de document : texte imprimé Auteurs : S. G. Kang, Auteur ; J. H. Hong, Auteur ; C. K. Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 11954–11960 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mechanical properties Nanocomposites Résumé : Nanocomposites of novolac phenolic resin with a series of organoclays based on sodium montmorillonite exchanged with various amine compatibilizers were fabricated via melt processing. The effects of the amine structure on the resulting morphology and physical properties were investigated by employing wide-angle X-ray scattering, transmission electron microscopy, viscosity measurement, flexural strength measurement, and Izod impact strength testing. All of the composites containing organoclay showed evidence of the intercalated state with a shift in the gallery spacing. The extent of silicate platelet intercalation was increased by (1) decreasing the number of long alkyl tails from two to one, (2) using methyl rather than polar hydroxyethyl groups or bulky groups such as 2-ethylhexyl or benzyl groups, and (3) using an equivalent amount of compatibilizer with the montmorillonite. Novolac phttp://atcatalogue_2.enp.edu.dz/catalog.php?categ=serials&sub=analysis&action=analysis_form&bul_id=15337&analysis_id=0henolic resin/organoclay nanocomposites cured with hexamethylenetetramine exhibited better flexural and Izod impact strength than the unmodified novolac phenolic resin. Nanocomposites with higher shifts in the platelet gallery height, i.e., higher platelet intercalation, showed better flexural and Izod impact strength. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002872 [article] Morphology and mechanical properties of nanocomposites fabricated from organoclays and a novolac phenolic resin via melt mixing [texte imprimé] / S. G. Kang, Auteur ; J. H. Hong, Auteur ; C. K. Kim, Auteur . - 2011 . - pp. 11954–11960. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11954–11960 Mots-clés : Mechanical properties Nanocomposites Résumé : Nanocomposites of novolac phenolic resin with a series of organoclays based on sodium montmorillonite exchanged with various amine compatibilizers were fabricated via melt processing. The effects of the amine structure on the resulting morphology and physical properties were investigated by employing wide-angle X-ray scattering, transmission electron microscopy, viscosity measurement, flexural strength measurement, and Izod impact strength testing. All of the composites containing organoclay showed evidence of the intercalated state with a shift in the gallery spacing. The extent of silicate platelet intercalation was increased by (1) decreasing the number of long alkyl tails from two to one, (2) using methyl rather than polar hydroxyethyl groups or bulky groups such as 2-ethylhexyl or benzyl groups, and (3) using an equivalent amount of compatibilizer with the montmorillonite. Novolac phttp://atcatalogue_2.enp.edu.dz/catalog.php?categ=serials&sub=analysis&action=analysis_form&bul_id=15337&analysis_id=0henolic resin/organoclay nanocomposites cured with hexamethylenetetramine exhibited better flexural and Izod impact strength than the unmodified novolac phenolic resin. Nanocomposites with higher shifts in the platelet gallery height, i.e., higher platelet intercalation, showed better flexural and Izod impact strength. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002872

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Polymeric Hollow-Fiber Heat Exchangers for Thermal Desalination Processes / Liming Song in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11961–11977 Titre : Polymeric Hollow-Fiber Heat Exchangers for Thermal Desalination Processes Type de document : texte imprimé Auteurs : Liming Song, Auteur ; Baoan Li, Auteur ; Dimitrios Zarkadas, Auteur Année de publication : 2011 Article en page(s) : pp. 11961–11977 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Heat Exchangers Thermal desalination Résumé : Metallic shell-and-tube heat exchangers used in thermal desalination require huge capital investments, suffer from corrosion/erosion, create heavy metal pollution, and display a large footprint. This paper has explored their potential replacement by polymeric solid hollow fiber-based heat exchangers. Using solid hollow-fibers of polypropylene (PP) (wall thickness 75 μm, outside diameter 575 μm) a number of heat exchangers were fabricated in the laboratory (heat exchange area, 195−960 cm2) and at a commercial manufacturing facility (heat exchange area, 0.15−0.44 m2). The heat transfer performances of these devices were studied for a hot brine (4% NaCl, ca. 80−98 °C)−cold water (8−25 °C) system as well as for a steam (101−113 °C)−cold water (8−25 °C) system; these systems are typically encountered in thermal desalination plants. Overall heat transfer coefficient values of as much as 2000 W/(m2 K) were achieved. This is close to the limiting value imposed by the PP wall thickness, namely, 2660 W/(m2 K). Heat exchangers built out of solid poly(ether ether ketone) (PEEK) fibers performed almost as well. Higher heat transfer coefficients were obtained by using porous asymmetric polyethersulfone hollow fibers whose internal diameter was coated by two consecutive layers of polyamide and silicone to make them impervious to moisture. A mathematical model has been developed to describe the solid hollow fiber heat exchanger performance and was proven a good predictor of heat transfer performance in such devices. Compared to metallic exchangers, these heat exchangers weigh much less, have an order of magnitude larger surface area per unit volume, and are likely to be considerably cheaper. Small polymeric heat exchange devices having an effective length less than 30.5 cm (1 ft.) achieve efficiencies close to 1, provide NTU values close to 4, and have HTU values as low as 5 cm. Further their conductance/volume values are as much as 2−15 times larger than metal heat exchangers. In addition, these devices have low flow pressure drops as low as 1 kPa/NTU compared to 30 kPa/NTU in conventional metal heat exchangers. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100375b [article] Polymeric Hollow-Fiber Heat Exchangers for Thermal Desalination Processes [texte imprimé] / Liming Song, Auteur ; Baoan Li, Auteur ; Dimitrios Zarkadas, Auteur . - 2011 . - pp. 11961–11977. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11961–11977 Mots-clés : Heat Exchangers Thermal desalination Résumé : Metallic shell-and-tube heat exchangers used in thermal desalination require huge capital investments, suffer from corrosion/erosion, create heavy metal pollution, and display a large footprint. This paper has explored their potential replacement by polymeric solid hollow fiber-based heat exchangers. Using solid hollow-fibers of polypropylene (PP) (wall thickness 75 μm, outside diameter 575 μm) a number of heat exchangers were fabricated in the laboratory (heat exchange area, 195−960 cm2) and at a commercial manufacturing facility (heat exchange area, 0.15−0.44 m2). The heat transfer performances of these devices were studied for a hot brine (4% NaCl, ca. 80−98 °C)−cold water (8−25 °C) system as well as for a steam (101−113 °C)−cold water (8−25 °C) system; these systems are typically encountered in thermal desalination plants. Overall heat transfer coefficient values of as much as 2000 W/(m2 K) were achieved. This is close to the limiting value imposed by the PP wall thickness, namely, 2660 W/(m2 K). Heat exchangers built out of solid poly(ether ether ketone) (PEEK) fibers performed almost as well. Higher heat transfer coefficients were obtained by using porous asymmetric polyethersulfone hollow fibers whose internal diameter was coated by two consecutive layers of polyamide and silicone to make them impervious to moisture. A mathematical model has been developed to describe the solid hollow fiber heat exchanger performance and was proven a good predictor of heat transfer performance in such devices. Compared to metallic exchangers, these heat exchangers weigh much less, have an order of magnitude larger surface area per unit volume, and are likely to be considerably cheaper. Small polymeric heat exchange devices having an effective length less than 30.5 cm (1 ft.) achieve efficiencies close to 1, provide NTU values close to 4, and have HTU values as low as 5 cm. Further their conductance/volume values are as much as 2−15 times larger than metal heat exchangers. In addition, these devices have low flow pressure drops as low as 1 kPa/NTU compared to 30 kPa/NTU in conventional metal heat exchangers. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100375b

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Thin - film nanofibrous composite ultrafiltration membranes based on polyvinyl alcohol barrier layer containing directional water channels / Hongyang Ma in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11978–11984 Titre : Thin - film nanofibrous composite ultrafiltration membranes based on polyvinyl alcohol barrier layer containing directional water channels Type de document : texte imprimé Auteurs : Hongyang Ma, Auteur ; Kyunghwan Yoon, Auteur ; Lixia Rong, Auteur Année de publication : 2011 Article en page(s) : pp. 11978–11984 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanofibrous Résumé : A new class of thin-film nanofibrous composite (TFNC) membranes, composed of a chemically cross-linked polyvinyl alcohol (PVA) barrier layer containing directional water channels through the incorporation of very fine nanofiber fillers, an electrospun polyacrylonitrile (PAN) nanofibrous scaffold midlayer, and a melt-blown polyethylene terephthalate (PET) nonwoven support, was demonstrated for ultrafiltration (UF) of oil/water emulsions. The permeation flux of TFNC membrane with a pure PVA barrier layer was already about 5 times higher than that of the commercial PAN10 (Sepro) UF membrane at low pressures (e.g., 30 psi), while maintaining a similar rejection ratio ( 99.7%). Two kinds of fine nanofiber fillers: oxidized multiwalled carbon nanotubes (MWCNTs) and cellulose nanofibers (CNs), were further incorporated into the PVA barrier layer to increase the permeation flux. The results indicated that permeation fluxes of MWCNT and CN filler-containing TFNC membranes were about 10-times higher than those of PAN10, while still maintaining a rejection ratio of 99.5%. The increase in the permeation flux could be attributed to the formation of directional water channels through the interface between the surface of MWCNT or CN fillers and that of the barrier layer and the interconnections among the fine nanofiber network. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100545k [article] Thin - film nanofibrous composite ultrafiltration membranes based on polyvinyl alcohol barrier layer containing directional water channels [texte imprimé] / Hongyang Ma, Auteur ; Kyunghwan Yoon, Auteur ; Lixia Rong, Auteur . - 2011 . - pp. 11978–11984. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11978–11984 Mots-clés : Nanofibrous Résumé : A new class of thin-film nanofibrous composite (TFNC) membranes, composed of a chemically cross-linked polyvinyl alcohol (PVA) barrier layer containing directional water channels through the incorporation of very fine nanofiber fillers, an electrospun polyacrylonitrile (PAN) nanofibrous scaffold midlayer, and a melt-blown polyethylene terephthalate (PET) nonwoven support, was demonstrated for ultrafiltration (UF) of oil/water emulsions. The permeation flux of TFNC membrane with a pure PVA barrier layer was already about 5 times higher than that of the commercial PAN10 (Sepro) UF membrane at low pressures (e.g., 30 psi), while maintaining a similar rejection ratio ( 99.7%). Two kinds of fine nanofiber fillers: oxidized multiwalled carbon nanotubes (MWCNTs) and cellulose nanofibers (CNs), were further incorporated into the PVA barrier layer to increase the permeation flux. The results indicated that permeation fluxes of MWCNT and CN filler-containing TFNC membranes were about 10-times higher than those of PAN10, while still maintaining a rejection ratio of 99.5%. The increase in the permeation flux could be attributed to the formation of directional water channels through the interface between the surface of MWCNT or CN fillers and that of the barrier layer and the interconnections among the fine nanofiber network. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100545k

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Linear viscoelasticity of spherical SiO2 nanoparticle - tethered poly(butyl acrylate) hybrids / Vivek Goel in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11985–11990 Titre : Linear viscoelasticity of spherical SiO2 nanoparticle - tethered poly(butyl acrylate) hybrids Type de document : texte imprimé Auteurs : Vivek Goel, Auteur ; Joanna Pietrasik, Auteur ; Krzysztof Matyjaszewski, Auteur Année de publication : 2011 Article en page(s) : pp. 11985–11990 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Viscoelasticity Nanoparticle Résumé : The melt state linear viscoelastic properties of spherical silica nanoparticles with grafted poly(n-butyl acrylate) chains of varying molecular weight were probed using linear small amplitude dynamic oscillatory measurements and complementary linear stress relaxation measurements. While the pure silica-tethered−polymer hybrids with no added homopolymer exhibit solid-like response, addition of matched molecular weight free matrix homopolymer chains to this hybrid, at low concentrations of added homopolymer, maintains the solid-like response with a lowered modulus that can be factored into a silica concentration dependence and a molecular weight dependence. While the silica concentration dependence of the modulus is strong, the dependence on molecular weight is weak. On the other hand, increasing the amount of added homopolymer changes the viscoelastic response to that of a liquid with a relaxation time that scales exponentially with hybrid concentration. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007129 [article] Linear viscoelasticity of spherical SiO2 nanoparticle - tethered poly(butyl acrylate) hybrids [texte imprimé] / Vivek Goel, Auteur ; Joanna Pietrasik, Auteur ; Krzysztof Matyjaszewski, Auteur . - 2011 . - pp. 11985–11990. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11985–11990 Mots-clés : Viscoelasticity Nanoparticle Résumé : The melt state linear viscoelastic properties of spherical silica nanoparticles with grafted poly(n-butyl acrylate) chains of varying molecular weight were probed using linear small amplitude dynamic oscillatory measurements and complementary linear stress relaxation measurements. While the pure silica-tethered−polymer hybrids with no added homopolymer exhibit solid-like response, addition of matched molecular weight free matrix homopolymer chains to this hybrid, at low concentrations of added homopolymer, maintains the solid-like response with a lowered modulus that can be factored into a silica concentration dependence and a molecular weight dependence. While the silica concentration dependence of the modulus is strong, the dependence on molecular weight is weak. On the other hand, increasing the amount of added homopolymer changes the viscoelastic response to that of a liquid with a relaxation time that scales exponentially with hybrid concentration. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1007129

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Complexation hydrogels for the oral delivery of growth hormone and salmon calcitonin / Daniel A. Carr in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11991–11995 Titre : Complexation hydrogels for the oral delivery of growth hormone and salmon calcitonin Type de document : texte imprimé Auteurs : Daniel A. Carr, Auteur ; Marta Gomez-Burgaz, Auteur ; Mathilde C. Boudes, Auteur Année de publication : 2011 Article en page(s) : pp. 11991–11995 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrogels Résumé : The hydrogel system of poly(methacrylic acid-co-N-vinyl pyrrolidone) P(MAA-co-NVP) was evaluated for use as an oral delivery system for growth hormone and salmon calcitonin. These proteins were selected because of their therapeutic importance and the insight provided by evaluating the delivery of a therapeutic agent with a high molecular weight (growth hormone) and a drug with a high isoelectric point (salmon calcitonin). Growth hormone loading and release studies were performed for both P(MAA-co-NVP) and P(MAA-g-poly(ethylene glycol)) (P(MAA-g-PEG)). Loading efficiencies for the respective systems were 50.9 ± 1.8% and 57.8 ± 4.1%; weight incorporation of the protein was determined to be 3.5 ± 0.1% and 4.0 ± 0.3%. At pH 7.4, growth hormone release of 90% occurred within 45 min for P(MAA-co-NVP) microparticles; 90% release was not achieved with P(MAA-g-PEG) microparticles until 180 min. At pH 1.2, no release occurred from P(MAA-co-NVP) microparticles, but 10% release occurred from P(MAA-g-PEG) microparticles. Salmon calcitonin loading and release were shown to be affected by the negative charges of deprotonated MAA; for systems with monomer molar feed ratios of 4:1, 1:1, and 1:4 MAA/NVP, loading efficiencies were determined to be 70.6 ± 3.0%, 25.3 ± 1.2%, and 1.6 ± 1.3%. Salmon calcitonin release was minimal from the copolymer with 4:1 MAA/NVP monomer feed at pH 7.4. The release improved when the pH was raised above physiological levels. These studies confirmed that P(MAA-co-NVP) was an effective oral delivery system for high molecular weight drugs, but improvements are needed before the system could be utilized for high isoelectric point therapeutic delivery. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008025 [article] Complexation hydrogels for the oral delivery of growth hormone and salmon calcitonin [texte imprimé] / Daniel A. Carr, Auteur ; Marta Gomez-Burgaz, Auteur ; Mathilde C. Boudes, Auteur . - 2011 . - pp. 11991–11995. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11991–11995 Mots-clés : Hydrogels Résumé : The hydrogel system of poly(methacrylic acid-co-N-vinyl pyrrolidone) P(MAA-co-NVP) was evaluated for use as an oral delivery system for growth hormone and salmon calcitonin. These proteins were selected because of their therapeutic importance and the insight provided by evaluating the delivery of a therapeutic agent with a high molecular weight (growth hormone) and a drug with a high isoelectric point (salmon calcitonin). Growth hormone loading and release studies were performed for both P(MAA-co-NVP) and P(MAA-g-poly(ethylene glycol)) (P(MAA-g-PEG)). Loading efficiencies for the respective systems were 50.9 ± 1.8% and 57.8 ± 4.1%; weight incorporation of the protein was determined to be 3.5 ± 0.1% and 4.0 ± 0.3%. At pH 7.4, growth hormone release of 90% occurred within 45 min for P(MAA-co-NVP) microparticles; 90% release was not achieved with P(MAA-g-PEG) microparticles until 180 min. At pH 1.2, no release occurred from P(MAA-co-NVP) microparticles, but 10% release occurred from P(MAA-g-PEG) microparticles. Salmon calcitonin loading and release were shown to be affected by the negative charges of deprotonated MAA; for systems with monomer molar feed ratios of 4:1, 1:1, and 1:4 MAA/NVP, loading efficiencies were determined to be 70.6 ± 3.0%, 25.3 ± 1.2%, and 1.6 ± 1.3%. Salmon calcitonin release was minimal from the copolymer with 4:1 MAA/NVP monomer feed at pH 7.4. The release improved when the pH was raised above physiological levels. These studies confirmed that P(MAA-co-NVP) was an effective oral delivery system for high molecular weight drugs, but improvements are needed before the system could be utilized for high isoelectric point therapeutic delivery. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1008025

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Experimental optimizing control of the simulated moving bed separation of tröger’s base enantiomers / Christian Langel in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11996-12003 Titre : Experimental optimizing control of the simulated moving bed separation of tröger’s base enantiomers Type de document : texte imprimé Auteurs : Christian Langel, Auteur ; Cristian Grossmann, Auteur ; Simon Jermann, Auteur Année de publication : 2011 Article en page(s) : pp. 11996-12003 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Enantiomer Simulated moving bed Optimization Résumé : Simulated moving bed (SMB) chromatography has become a well-established technique in the pharmaceutical industry and biotechnology for the separation of enantiomers. However, exploiting the full economic potential of the process is not trivial, and therefore, we developed a “cycle-to-cycle” optimizing controller to facilitate the operation of SMB units close to the economic optimum. The proposed controller only requires the information about the linear adsorption behavior and the average porosity of the columns. This paper presents the different steps required to set up our controller for a given separation problem, namely the separation of Tröger’s Base enantiomers. For the investigated system, the complete adsorption isotherm is available which allows us to carry out detailed simulations and to compare them to the actual experiments. Hence, one can judge how well the simulations can predict both the dynamic and the steady state behavior of the controller at different feed concentrations. The paper demonstrates that the control concept is simple enough to be implemented quickly and reliably for a new separation campaign within three days. Furthermore, the experimental results clearly show that despite process disturbances the controller is able to fulfill the product specifications and to improve the process performance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463356 [article] Experimental optimizing control of the simulated moving bed separation of tröger’s base enantiomers [texte imprimé] / Christian Langel, Auteur ; Cristian Grossmann, Auteur ; Simon Jermann, Auteur . - 2011 . - pp. 11996-12003. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 11996-12003 Mots-clés : Enantiomer Simulated moving bed Optimization Résumé : Simulated moving bed (SMB) chromatography has become a well-established technique in the pharmaceutical industry and biotechnology for the separation of enantiomers. However, exploiting the full economic potential of the process is not trivial, and therefore, we developed a “cycle-to-cycle” optimizing controller to facilitate the operation of SMB units close to the economic optimum. The proposed controller only requires the information about the linear adsorption behavior and the average porosity of the columns. This paper presents the different steps required to set up our controller for a given separation problem, namely the separation of Tröger’s Base enantiomers. For the investigated system, the complete adsorption isotherm is available which allows us to carry out detailed simulations and to compare them to the actual experiments. Hence, one can judge how well the simulations can predict both the dynamic and the steady state behavior of the controller at different feed concentrations. The paper demonstrates that the control concept is simple enough to be implemented quickly and reliably for a new separation campaign within three days. Furthermore, the experimental results clearly show that despite process disturbances the controller is able to fulfill the product specifications and to improve the process performance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463356

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An inexact trust - region algorithm for the optimization of periodic adsorption processes / Sree Rama Raju Vetukuri in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12004–12013 Titre : An inexact trust - region algorithm for the optimization of periodic adsorption processes Type de document : texte imprimé Auteurs : Sree Rama Raju Vetukuri, Auteur ; Lorenz T. Biegler, Auteur ; Andrea Walther, Auteur Année de publication : 2011 Article en page(s) : pp.12004–12013 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optimization Adsorption Résumé : Periodic adsorption processes have gained increasing commercial importance as an energy-efficient separation technique over the past two decades. Based on fluid−solid interactions, these systems never reach steady state. Instead they operate at cyclic steady state, where the bed conditions at the beginning of the cycle match with those at the end of the cycle. Nevertheless, optimization of these processes remains particularly challenging, because cyclic operation leads to dense Jacobians, whose computation dominates the overall cost of the optimization strategy. To efficiently handle these Jacobians during optimization and reduce the computation time, this work presents a new composite step trust-region algorithm for the solution of minimization problems with both nonlinear equality and inequality constraints, and combines two approaches developed in Walther(1) and Arora and Biegler.(2) Instead of forming and factoring the dense constraint Jacobian, this algorithm approximates the Jacobian of equality constraints with a specialized quasi-Newton method. Hence it is well suited to solve optimization problems related to periodic adsorption processes. In addition to allowing inexactness of the Jacobian and its null-space representation, the algorithm also provides exact second-order information in the form of Hessian−vector products to improve the convergence rate. The resulting approach(3) also combines automatic differentiation and more sophisticated integration algorithms to evaluate the direct sensitivity and adjoint sensitivity equations. A 5-fold reduction in computation is demonstrated with this approach for two periodic adsorption optimization problems: a simulated moving bed system and a nonisothermal vacuum swing adsorption O2 bulk gas separation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100706c [article] An inexact trust - region algorithm for the optimization of periodic adsorption processes [texte imprimé] / Sree Rama Raju Vetukuri, Auteur ; Lorenz T. Biegler, Auteur ; Andrea Walther, Auteur . - 2011 . - pp.12004–12013. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12004–12013 Mots-clés : Optimization Adsorption Résumé : Periodic adsorption processes have gained increasing commercial importance as an energy-efficient separation technique over the past two decades. Based on fluid−solid interactions, these systems never reach steady state. Instead they operate at cyclic steady state, where the bed conditions at the beginning of the cycle match with those at the end of the cycle. Nevertheless, optimization of these processes remains particularly challenging, because cyclic operation leads to dense Jacobians, whose computation dominates the overall cost of the optimization strategy. To efficiently handle these Jacobians during optimization and reduce the computation time, this work presents a new composite step trust-region algorithm for the solution of minimization problems with both nonlinear equality and inequality constraints, and combines two approaches developed in Walther(1) and Arora and Biegler.(2) Instead of forming and factoring the dense constraint Jacobian, this algorithm approximates the Jacobian of equality constraints with a specialized quasi-Newton method. Hence it is well suited to solve optimization problems related to periodic adsorption processes. In addition to allowing inexactness of the Jacobian and its null-space representation, the algorithm also provides exact second-order information in the form of Hessian−vector products to improve the convergence rate. The resulting approach(3) also combines automatic differentiation and more sophisticated integration algorithms to evaluate the direct sensitivity and adjoint sensitivity equations. A 5-fold reduction in computation is demonstrated with this approach for two periodic adsorption optimization problems: a simulated moving bed system and a nonisothermal vacuum swing adsorption O2 bulk gas separation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100706c

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Structural determination of extem XH 1015 and its gas permeability comparison with polysulfone and ultem via molecular simulation / Jianzhong Xia in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12014–12021 Titre : Structural determination of extem XH 1015 and its gas permeability comparison with polysulfone and ultem via molecular simulation Type de document : texte imprimé Auteurs : Jianzhong Xia, Auteur ; Songlin Liu, Auteur ; Pramoda Kumari Pallathadka, Auteur Année de publication : 2011 Article en page(s) : pp. 12014–12021 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling Molecular model Gas permeability Résumé : By employing high resolution 1H and 13C NMR spectroscopy combined with elemental analysis and FTIR-ATR, we have determined the basic chemical structure of Extem XH 1015, a new brand of polyetherimide with good thermal, mechanical properties, and processability. Bisphenol-A dianhydride (BPADA) and diamino diphenyl sulfone (DDS) are found to be the monomers for this newly developed polyetherimide. The gas permeability of this new polymer is reported for the first time in the literature. Polysulfone (PSU) and Ultem are employed as reference samples for the elucidation of permeability and selectivity differences among them because of their structural similarities. In addition to qualitative comparison of chain rigidity and packing with gas transport properties, computational simulations powered by Material Studio are performed at a molecular level to quantitatively investigate the relationship between the fractional accessible volume (FAV) and gas permeability. The FAV differences among these polymers increase with an increase in gas molecules diameters; thus these polymers have similar permeability for small gas molecules but diverse for large gas molecules. Their selectivity differences are also discussed in terms of FAV ratio. The FAV concept is proved to be more effective than fractional free volume to analyze and predict gas separation performance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463358 [article] Structural determination of extem XH 1015 and its gas permeability comparison with polysulfone and ultem via molecular simulation [texte imprimé] / Jianzhong Xia, Auteur ; Songlin Liu, Auteur ; Pramoda Kumari Pallathadka, Auteur . - 2011 . - pp. 12014–12021. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12014–12021 Mots-clés : Modeling Molecular model Gas permeability Résumé : By employing high resolution 1H and 13C NMR spectroscopy combined with elemental analysis and FTIR-ATR, we have determined the basic chemical structure of Extem XH 1015, a new brand of polyetherimide with good thermal, mechanical properties, and processability. Bisphenol-A dianhydride (BPADA) and diamino diphenyl sulfone (DDS) are found to be the monomers for this newly developed polyetherimide. The gas permeability of this new polymer is reported for the first time in the literature. Polysulfone (PSU) and Ultem are employed as reference samples for the elucidation of permeability and selectivity differences among them because of their structural similarities. In addition to qualitative comparison of chain rigidity and packing with gas transport properties, computational simulations powered by Material Studio are performed at a molecular level to quantitatively investigate the relationship between the fractional accessible volume (FAV) and gas permeability. The FAV differences among these polymers increase with an increase in gas molecules diameters; thus these polymers have similar permeability for small gas molecules but diverse for large gas molecules. Their selectivity differences are also discussed in terms of FAV ratio. The FAV concept is proved to be more effective than fractional free volume to analyze and predict gas separation performance. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463358

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Selective separation of cephalexin from multiple component mixtures / Michael E. Vilt in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12022–12030 Titre : Selective separation of cephalexin from multiple component mixtures Type de document : texte imprimé Auteurs : Michael E. Vilt, Auteur ; W. S. Winston Ho, Auteur Année de publication : 2011 Article en page(s) : pp. 12022–12030 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Cephalexin Résumé : Supported liquid membranes (SLMs) with strip dispersion and carrier, Aliquat 336, were used for the selective recovery of Cephalexin from simulated enzymatic solutions for Cephalexin synthesis. For the Cephalexin-containing feed solution, pH control methods using constant NaOH titration, carbonate buffer, and phosphate buffer were compared. Carbonate buffers with concentrations of 0.05 and 0.10 M gave the highest extraction and recovery, in which recovery for both cases was over 99%. Optimal extraction of Cephalexin from feed solutions containing equimolar concentrations of 7-amino-3-desacetoxicephalosporanic acid (7-ADCA) occurred at a feed solution pH = 9.5, resulting in a separation factor of 12.1. The recovery of Cephalexin from solutions containing 7-ADCA, phenylglycine amide (PGA), and phenylglycine (PG) was also demonstrated. Improved Cephalexin extraction was achieved at a feed pH = 8.0 when compared to a feed pH = 9.5 due to high coextraction of PG at the latter. At a feed pH = 8.0 and a feed solution composition of 15, 15, 15, and 3 mM for Cephalexin, 7-ADCA, PG, and PGA, respectively, an initial Cephalexin flux of 3.1 g/(m2 h) was achieved. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100073w [article] Selective separation of cephalexin from multiple component mixtures [texte imprimé] / Michael E. Vilt, Auteur ; W. S. Winston Ho, Auteur . - 2011 . - pp. 12022–12030. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12022–12030 Mots-clés : Cephalexin Résumé : Supported liquid membranes (SLMs) with strip dispersion and carrier, Aliquat 336, were used for the selective recovery of Cephalexin from simulated enzymatic solutions for Cephalexin synthesis. For the Cephalexin-containing feed solution, pH control methods using constant NaOH titration, carbonate buffer, and phosphate buffer were compared. Carbonate buffers with concentrations of 0.05 and 0.10 M gave the highest extraction and recovery, in which recovery for both cases was over 99%. Optimal extraction of Cephalexin from feed solutions containing equimolar concentrations of 7-amino-3-desacetoxicephalosporanic acid (7-ADCA) occurred at a feed solution pH = 9.5, resulting in a separation factor of 12.1. The recovery of Cephalexin from solutions containing 7-ADCA, phenylglycine amide (PGA), and phenylglycine (PG) was also demonstrated. Improved Cephalexin extraction was achieved at a feed pH = 8.0 when compared to a feed pH = 9.5 due to high coextraction of PG at the latter. At a feed pH = 8.0 and a feed solution composition of 15, 15, 15, and 3 mM for Cephalexin, 7-ADCA, PG, and PGA, respectively, an initial Cephalexin flux of 3.1 g/(m2 h) was achieved. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100073w

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Intermolecular Interactions / Yuri Yampolskii in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12031–12037 Titre : Intermolecular Interactions : New Way to Govern Transport Properties of Membrane Materials Type de document : texte imprimé Auteurs : Yuri Yampolskii, Auteur ; Alexandre Alentiev, Auteur ; Galina Bondarenko, Auteur Année de publication : 2011 Article en page(s) : pp. 12031–12037 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polyetherimides Polymers Résumé : Investigation of the gas permeation parameters of several polyetherimides and polymers of intrinsic microporosity showed that their properties (permeability and permselecitivity) are sensitive to the presence of low molecular mass compounds (chloroform, lower alcohols, water) that are capable of forming hydrogen bonds. Using the FTIR method and quantum chemical calculations, it was shown that such bonds are formed and they induce structural (conformation) changes in the polymer matrices. Other types of weak interactions, dipole−dipole interactions, are responsible for unusual sorption behavior of acetone in amorphous Teflon AF2400. Therefore, intermolecular interactions can influence transport and sorption properties of glassy membrane materials. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100097a [article] Intermolecular Interactions : New Way to Govern Transport Properties of Membrane Materials [texte imprimé] / Yuri Yampolskii, Auteur ; Alexandre Alentiev, Auteur ; Galina Bondarenko, Auteur . - 2011 . - pp. 12031–12037. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12031–12037 Mots-clés : Polyetherimides Polymers Résumé : Investigation of the gas permeation parameters of several polyetherimides and polymers of intrinsic microporosity showed that their properties (permeability and permselecitivity) are sensitive to the presence of low molecular mass compounds (chloroform, lower alcohols, water) that are capable of forming hydrogen bonds. Using the FTIR method and quantum chemical calculations, it was shown that such bonds are formed and they induce structural (conformation) changes in the polymer matrices. Other types of weak interactions, dipole−dipole interactions, are responsible for unusual sorption behavior of acetone in amorphous Teflon AF2400. Therefore, intermolecular interactions can influence transport and sorption properties of glassy membrane materials. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100097a

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Hollow Fiber Sorbents for Desulfurization of Natural Gas / Dhaval A. Bhandari in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12038–12050 Titre : Hollow Fiber Sorbents for Desulfurization of Natural Gas Type de document : texte imprimé Auteurs : Dhaval A. Bhandari, Auteur ; Naoki Bessho, Auteur ; William J. Koros, Auteur Année de publication : 2011 Article en page(s) : pp.12038–12050 Note générale : Chimie industrielle Langues : Anglais (eng) Résumé : Pipeline natural gas is the primary fuel of choice for distributed fuel cell-based applications due to its well-developed infrastructure. The concentration of sulfur in odorized pipeline natural gas is about 30 ppm, with the acceptable level being DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100157w [article] Hollow Fiber Sorbents for Desulfurization of Natural Gas [texte imprimé] / Dhaval A. Bhandari, Auteur ; Naoki Bessho, Auteur ; William J. Koros, Auteur . - 2011 . - pp.12038–12050. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12038–12050 Résumé : Pipeline natural gas is the primary fuel of choice for distributed fuel cell-based applications due to its well-developed infrastructure. The concentration of sulfur in odorized pipeline natural gas is about 30 ppm, with the acceptable level being DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100157w

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Block copolymer derived membranes for sustained carbon dioxide − methane separations / Sarah E. Querelle in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12051–12059 Titre : Block copolymer derived membranes for sustained carbon dioxide − methane separations Type de document : texte imprimé Auteurs : Sarah E. Querelle, Auteur ; Chen, Liang, Auteur ; Marc A. Hillmyer, Auteur Année de publication : 2011 Article en page(s) : pp. 12051–12059 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymer Résumé : Using a reactive block polymer precursor, membranes with a bicontinuous nanostructure containing a poly((N,N-dimethylamino)ethyl methacrylate) phase within a cross-linked poly(cyclooctene) framework were formed. These membranes were evaluated for their CO2 selectivity over CH4. Low pressure experiments demonstrated that the CO2 and CH4 permeabilities remain the same with pure and mixed gas feeds. This shows that the membranes are able to maintain their selectivity for CO2. This selectivity was only slightly decreased at moderate temperature (35 °C) and higher pressures (up to 40 bar) using a 50/50 CO2/CH4 mixed gas feed. The bicontinuous block polymer membranes resist the plasticization effect by using a cross-linked phase to sustain the properties of the selective block, and not by changing chain mobility through new chemistry. These bicontinuous block polymer membranes may be valuable for CO2 removal from natural gas streams. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100461k [article] Block copolymer derived membranes for sustained carbon dioxide − methane separations [texte imprimé] / Sarah E. Querelle, Auteur ; Chen, Liang, Auteur ; Marc A. Hillmyer, Auteur . - 2011 . - pp. 12051–12059. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12051–12059 Mots-clés : Polymer Résumé : Using a reactive block polymer precursor, membranes with a bicontinuous nanostructure containing a poly((N,N-dimethylamino)ethyl methacrylate) phase within a cross-linked poly(cyclooctene) framework were formed. These membranes were evaluated for their CO2 selectivity over CH4. Low pressure experiments demonstrated that the CO2 and CH4 permeabilities remain the same with pure and mixed gas feeds. This shows that the membranes are able to maintain their selectivity for CO2. This selectivity was only slightly decreased at moderate temperature (35 °C) and higher pressures (up to 40 bar) using a 50/50 CO2/CH4 mixed gas feed. The bicontinuous block polymer membranes resist the plasticization effect by using a cross-linked phase to sustain the properties of the selective block, and not by changing chain mobility through new chemistry. These bicontinuous block polymer membranes may be valuable for CO2 removal from natural gas streams. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100461k

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Synthesis and gas transport properties of polyesters and a copolyester obtained from 4,4 - (9 - Fluorenylidene) bisphenol and 4,4 - (1 - Phenylethylidene) bisphenol / M. Isabel Loria - Bastarrachea in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12060–12066 Titre : Synthesis and gas transport properties of polyesters and a copolyester obtained from 4,4 - (9 - Fluorenylidene) bisphenol and 4,4 - (1 - Phenylethylidene) bisphenol Type de document : texte imprimé Auteurs : M. Isabel Loria - Bastarrachea, Auteur ; Manuel Aguilar-Vega, Auteur Année de publication : 2011 Article en page(s) : pp. 12060–12066 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gas Polyesters Bisphenol Résumé : Two isophthalic polyesters synthesized from 4,4′-(9-fluorenylidene) bisphenol, BF, and 4,4′-(1-phenylethylidene) bisphenol, BAP, and a random copolyester made from BF and BAP containing 50 mol % of these aromatic diols were prepared by interfacial polymerization. The resulting polyesters show glass transition temperatures, Tg, above 200 °C and onset of decomposition temperatures above 440 °C. The values of these thermal properties in the copolyester BAP50/ISO fall between those of the polyesters. It was also found that the thermal stability and maximum on the α-transition of the damping factor, tan δ, of BF/ISO were higher than those of BAP/ISO which is an indication of higher rigidity in the former. Wide-angle X-ray diffraction measurements indicated that both the homopolyesters and copolyester were amorphous. The copolyester showed an amorphous pattern with maxima that fell between those of the polyesters. Pure gas permeation measurements in films cast from solution show that gas permeability coefficients increase as the fractional free volume, FFV, of the polyester increases. This is attributed to a lower packing in BF/ISO as compared to BAP/ISO which increases the free volume available for gas permeation. The copolyester shows FFV and permeability coefficients that are intermediate between those exhibited by the homopolyesters. It was also found that ideal gas separation factors for O2/N2, CO2/CH4, and CO2/N2 are higher for BF/ISO which also shows the highest permeability coefficients. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100478v [article] Synthesis and gas transport properties of polyesters and a copolyester obtained from 4,4 - (9 - Fluorenylidene) bisphenol and 4,4 - (1 - Phenylethylidene) bisphenol [texte imprimé] / M. Isabel Loria - Bastarrachea, Auteur ; Manuel Aguilar-Vega, Auteur . - 2011 . - pp. 12060–12066. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12060–12066 Mots-clés : Gas Polyesters Bisphenol Résumé : Two isophthalic polyesters synthesized from 4,4′-(9-fluorenylidene) bisphenol, BF, and 4,4′-(1-phenylethylidene) bisphenol, BAP, and a random copolyester made from BF and BAP containing 50 mol % of these aromatic diols were prepared by interfacial polymerization. The resulting polyesters show glass transition temperatures, Tg, above 200 °C and onset of decomposition temperatures above 440 °C. The values of these thermal properties in the copolyester BAP50/ISO fall between those of the polyesters. It was also found that the thermal stability and maximum on the α-transition of the damping factor, tan δ, of BF/ISO were higher than those of BAP/ISO which is an indication of higher rigidity in the former. Wide-angle X-ray diffraction measurements indicated that both the homopolyesters and copolyester were amorphous. The copolyester showed an amorphous pattern with maxima that fell between those of the polyesters. Pure gas permeation measurements in films cast from solution show that gas permeability coefficients increase as the fractional free volume, FFV, of the polyester increases. This is attributed to a lower packing in BF/ISO as compared to BAP/ISO which increases the free volume available for gas permeation. The copolyester shows FFV and permeability coefficients that are intermediate between those exhibited by the homopolyesters. It was also found that ideal gas separation factors for O2/N2, CO2/CH4, and CO2/N2 are higher for BF/ISO which also shows the highest permeability coefficients. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100478v

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Ethanol dehydration using hydrophobic and hydrophilic polymer membranes / Yu Huang in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12067–12073 Titre : Ethanol dehydration using hydrophobic and hydrophilic polymer membranes Type de document : texte imprimé Auteurs : Yu Huang, Auteur ; Jennifer Ly, Auteur ; Dung Nguyen, Auteur Année de publication : 2011 Article en page(s) : pp. 12067–12073 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ethanol Hydrophobic Polymer Résumé : This paper describes the development of membranes based on perfluoro polymers for the separation of aqueous ethanol mixtures in pervaporation or vapor permeation mode. Hydrophobic perfluoro polymers were selected because their chemical and thermal stability allows them to be used at temperatures up to 130 °C in hot ethanol/water vapors. The permeance and selectivity of membranes made from these polymers are quite different from the properties of the cross-linked hydrophilic membranes that are commonly used to separate water/ethanol mixtures. Perfluoro polymers absorb less than 1% liquid in mixtures ranging from pure water to pure ethanol. As a result, the water permeance and water/ethanol selectivity of the membranes are essentially independent of feed water/ethanol composition. However, the water permeances of perfluoro membranes are low for commercial applications. Multilayer composite membranes, consisting of a perfluoro protective layer and a selective hydrophilic polymer underlayer, have the stability of hydrophobic perfluoro membranes combined with the high permeances and good selectivities of hydrophilic membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100608s [article] Ethanol dehydration using hydrophobic and hydrophilic polymer membranes [texte imprimé] / Yu Huang, Auteur ; Jennifer Ly, Auteur ; Dung Nguyen, Auteur . - 2011 . - pp. 12067–12073. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12067–12073 Mots-clés : Ethanol Hydrophobic Polymer Résumé : This paper describes the development of membranes based on perfluoro polymers for the separation of aqueous ethanol mixtures in pervaporation or vapor permeation mode. Hydrophobic perfluoro polymers were selected because their chemical and thermal stability allows them to be used at temperatures up to 130 °C in hot ethanol/water vapors. The permeance and selectivity of membranes made from these polymers are quite different from the properties of the cross-linked hydrophilic membranes that are commonly used to separate water/ethanol mixtures. Perfluoro polymers absorb less than 1% liquid in mixtures ranging from pure water to pure ethanol. As a result, the water permeance and water/ethanol selectivity of the membranes are essentially independent of feed water/ethanol composition. However, the water permeances of perfluoro membranes are low for commercial applications. Multilayer composite membranes, consisting of a perfluoro protective layer and a selective hydrophilic polymer underlayer, have the stability of hydrophobic perfluoro membranes combined with the high permeances and good selectivities of hydrophilic membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100608s

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Effect of FiberProperty variation on hollow fiber membrane module performance in the production of a permeate product / Santosh A. Sonalkar in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12074–12083 Titre : Effect of FiberProperty variation on hollow fiber membrane module performance in the production of a permeate product Type de document : texte imprimé Auteurs : Santosh A. Sonalkar, Auteur ; Pingjiao Hao, Auteur ; G. Glenn Lipscomb, Auteur Année de publication : 2011 Article en page(s) : pp. 12074–12083 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fiber Résumé : The literature demonstrates the detrimental effects of variability in the inner diameter, permeance, and selectivity of hollow fiber membranes for the production of a retentate product, for example, nitrogen purification from air. This past work is extended to the production of a permeate product. Additionally, simultaneous variation of multiple fiber properties is considered. Fiber variability is detrimental to permeate production; the ratio of product to feed flow rate decreases with an increase in variability. However, the permeate product flow rate remains unchanged in contrast to the large changes observed for a retentate product. Simultaneous, independent variation of multiple fiber properties makes performance worse. However, correlations between the variations in fiber properties can improve performance. Theoretical performance predictions compare favorably with experimental measurements for the production of oxygen from air if either simultaneous variation of fiber size with permeance occurs or significant deviations from countercurrent flow exist. The results may be used to develop manufacturing guidelines for the production of hollow fiber membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100649q [article] Effect of FiberProperty variation on hollow fiber membrane module performance in the production of a permeate product [texte imprimé] / Santosh A. Sonalkar, Auteur ; Pingjiao Hao, Auteur ; G. Glenn Lipscomb, Auteur . - 2011 . - pp. 12074–12083. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12074–12083 Mots-clés : Fiber Résumé : The literature demonstrates the detrimental effects of variability in the inner diameter, permeance, and selectivity of hollow fiber membranes for the production of a retentate product, for example, nitrogen purification from air. This past work is extended to the production of a permeate product. Additionally, simultaneous variation of multiple fiber properties is considered. Fiber variability is detrimental to permeate production; the ratio of product to feed flow rate decreases with an increase in variability. However, the permeate product flow rate remains unchanged in contrast to the large changes observed for a retentate product. Simultaneous, independent variation of multiple fiber properties makes performance worse. However, correlations between the variations in fiber properties can improve performance. Theoretical performance predictions compare favorably with experimental measurements for the production of oxygen from air if either simultaneous variation of fiber size with permeance occurs or significant deviations from countercurrent flow exist. The results may be used to develop manufacturing guidelines for the production of hollow fiber membranes. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100649q

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Atomic - force and optical microscopy investigations on thin - film morphology of spherulites in melt - crystallized poly(ethylene adipate) / Andreas Meyer in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12084–12092 Titre : Atomic - force and optical microscopy investigations on thin - film morphology of spherulites in melt - crystallized poly(ethylene adipate) Type de document : texte imprimé Auteurs : Andreas Meyer, Auteur ; Kai Cheng Yen, Auteur ; Shu-Hsien Li, Auteur Année de publication : 2011 Article en page(s) : pp. 12084–12092 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Optical microscopy Résumé : The thin-film morphologies of double-ring-banded and ringless spherulites in melt-crystallized poly(ethylene adipate) (PEA) were examined using atomic-force microscopy (AFM) and polarizing optical microscopy techniques with phase image and depth profiles. For the PEA ring-banded spherulites (Tc = 30 °C), edge-on lamellae, with top views shaped like a figure 8, are arranged in an orderly fashion on the ridges of ring bands, and the valley region of the ring bands is filled mainly with flat-on oval-shaped platelets. Between the edge-on and flat-on band regions, some ribbonlike long lamellae are present that propagate across these two regions. However, these three lamellar types are discrete, discontinuous, and independent, and they are not necessarily inter-related by physical turning. By contrast, in the ringless Maltese-cross spherulite (PEA crystallized at Tc = 35 °C), similarly figure-8-shaped edge-on lamellae and flat-on platelets are also present, but they are scattered randomly, and no long lamellae are present. Near or within the edge-on lamellae, cavities are present as a result of densification and/or reorientation. In contrast with some single-banded spherulites where the valleys usually have a featureless amorphous texture, the valleys in the double-ring-banded PEA spherulites are filled with plateletlike lamellae, whereas the ridges contain mainly figure-8-shaped lamellae. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901356q [article] Atomic - force and optical microscopy investigations on thin - film morphology of spherulites in melt - crystallized poly(ethylene adipate) [texte imprimé] / Andreas Meyer, Auteur ; Kai Cheng Yen, Auteur ; Shu-Hsien Li, Auteur . - 2011 . - pp. 12084–12092. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12084–12092 Mots-clés : Optical microscopy Résumé : The thin-film morphologies of double-ring-banded and ringless spherulites in melt-crystallized poly(ethylene adipate) (PEA) were examined using atomic-force microscopy (AFM) and polarizing optical microscopy techniques with phase image and depth profiles. For the PEA ring-banded spherulites (Tc = 30 °C), edge-on lamellae, with top views shaped like a figure 8, are arranged in an orderly fashion on the ridges of ring bands, and the valley region of the ring bands is filled mainly with flat-on oval-shaped platelets. Between the edge-on and flat-on band regions, some ribbonlike long lamellae are present that propagate across these two regions. However, these three lamellar types are discrete, discontinuous, and independent, and they are not necessarily inter-related by physical turning. By contrast, in the ringless Maltese-cross spherulite (PEA crystallized at Tc = 35 °C), similarly figure-8-shaped edge-on lamellae and flat-on platelets are also present, but they are scattered randomly, and no long lamellae are present. Near or within the edge-on lamellae, cavities are present as a result of densification and/or reorientation. In contrast with some single-banded spherulites where the valleys usually have a featureless amorphous texture, the valleys in the double-ring-banded PEA spherulites are filled with plateletlike lamellae, whereas the ridges contain mainly figure-8-shaped lamellae. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901356q

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Micellar morphology in sulfonated pentablock copolymer solutions / Jae-Hong Choi in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12093–12097 Titre : Micellar morphology in sulfonated pentablock copolymer solutions Type de document : texte imprimé Auteurs : Jae-Hong Choi, Auteur ; Arun Kota, Auteur ; Karen I. Winey, Auteur Année de publication : 2011 Article en page(s) : pp.12093–12097 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Pentablock copolymer Résumé : The morphology of solutions of poly[t-butyl styrene-b-hydrogenated isoprene-b-sulfonated styrene-b-hydrogenated isoprene-b-t-butyl styrene] (tBS-HI-SS-HI-tBS) pentablock copolymers with a range of sulfonation levels was studied by small-angle X-ray scattering and transmission electron microscopy. For dilute pentablock copolymer solutions, TEM confirms the spherical micellar morphology. Small-angle X-ray scattering results and their interpretation using the Kinning−Thomas model reveal that sulfonated pentablock copolymer solutions with all levels of sulfonation exhibit spherical micellar morphologies with a core of SS and a corona of solvated HI-tBS. Both the radius of the micelle core and the closest approach distance between cores increase with sulfonation level, while the number density of micelles decreases. The calculated fraction of micelles per unit volume shows an increase and then a plateau with sulfonation level. The manipulation of micelle size dramatically impacts the processability. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002476 [article] Micellar morphology in sulfonated pentablock copolymer solutions [texte imprimé] / Jae-Hong Choi, Auteur ; Arun Kota, Auteur ; Karen I. Winey, Auteur . - 2011 . - pp.12093–12097. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12093–12097 Mots-clés : Pentablock copolymer Résumé : The morphology of solutions of poly[t-butyl styrene-b-hydrogenated isoprene-b-sulfonated styrene-b-hydrogenated isoprene-b-t-butyl styrene] (tBS-HI-SS-HI-tBS) pentablock copolymers with a range of sulfonation levels was studied by small-angle X-ray scattering and transmission electron microscopy. For dilute pentablock copolymer solutions, TEM confirms the spherical micellar morphology. Small-angle X-ray scattering results and their interpretation using the Kinning−Thomas model reveal that sulfonated pentablock copolymer solutions with all levels of sulfonation exhibit spherical micellar morphologies with a core of SS and a corona of solvated HI-tBS. Both the radius of the micelle core and the closest approach distance between cores increase with sulfonation level, while the number density of micelles decreases. The calculated fraction of micelles per unit volume shows an increase and then a plateau with sulfonation level. The manipulation of micelle size dramatically impacts the processability. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1002476

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Synthesis and properties of linear poly (ether sulfone)s with hyperbranched terminal groups / Keiichi Osano in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12098–12103 Titre : Synthesis and properties of linear poly (ether sulfone)s with hyperbranched terminal groups Type de document : texte imprimé Auteurs : Keiichi Osano, Auteur ; Lauren Force, Auteur ; S. Richard Turner, Auteur Année de publication : 2011 Article en page(s) : pp. 12098–12103 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymers Résumé : Linear−dendritic ABA copolymers, where A and B are hyperbranched and linear polymers, respectively, were synthesized by growing hyperbranched poly(ether ketone)s onto the ends of fluoro-terminated poly(ether sulfone)s. The unreacted fluoro-terminal groups of the hyperbranched polymers were capped by tert-butylphenol. The reactions were carried out at 90 °C to suppress ether cleavage. The results from NMR and SEC showed that multiple tert-butylphenol units were successfully attached to the terminal segments of the polymers. Analogous systems with sulfonated end groups were also synthesized by capping the fluoro terminal groups with a sulfonated phenol. This synthetic method is a versatile way to introduce multiple functional groups onto the ends of poly(ether sulfone)s. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100236y [article] Synthesis and properties of linear poly (ether sulfone)s with hyperbranched terminal groups [texte imprimé] / Keiichi Osano, Auteur ; Lauren Force, Auteur ; S. Richard Turner, Auteur . - 2011 . - pp. 12098–12103. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12098–12103 Mots-clés : Polymers Résumé : Linear−dendritic ABA copolymers, where A and B are hyperbranched and linear polymers, respectively, were synthesized by growing hyperbranched poly(ether ketone)s onto the ends of fluoro-terminated poly(ether sulfone)s. The unreacted fluoro-terminal groups of the hyperbranched polymers were capped by tert-butylphenol. The reactions were carried out at 90 °C to suppress ether cleavage. The results from NMR and SEC showed that multiple tert-butylphenol units were successfully attached to the terminal segments of the polymers. Analogous systems with sulfonated end groups were also synthesized by capping the fluoro terminal groups with a sulfonated phenol. This synthetic method is a versatile way to introduce multiple functional groups onto the ends of poly(ether sulfone)s. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100236y

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Preliminary observations of the role of material morphology on protein - electrophoretic transport in gold nanocomposite hydrogels / Jeffery W. Thompson in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12104–12110 Titre : Preliminary observations of the role of material morphology on protein - electrophoretic transport in gold nanocomposite hydrogels Type de document : texte imprimé Auteurs : Jeffery W. Thompson, Auteur ; Holly A. Stretz, Auteur ; Pedro E. Arce, Auteur Année de publication : 2011 Article en page(s) : pp. 12104–12110 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Gold Nanocomposite Résumé : Nanocomposite polymeric hydrogels have potential to play an important role in clinical diagnostics, therapeutic agents, and electroanalytical devices, among other biotechnological applications. However, the relationship between nanocomposite structure (morphology) and transport specifically of proteins has not been systematically described. In this study, polyacrylamide (PAM) nanocomposites have been synthesized containing various compositions and aspect ratios of gold nanoparticles (GNP). These nanocomposite hydrogels have been characterized for morphology, and examined for their ability to change the effective electrophoretic mobility of a model protein, ovum serum albumin (OSA), under a low applied electric field of 6.7 V/cm. Addition of spherical (low aspect ratio) gold nanoparticles reduces the effective mobility of OSA, a result that cannot be explained by the lower effective cross-link density noted in swelling studies. However, the effective mobility of OSA can be predicted using simple tortuous path models, specifically the Lape−Cussler. An increase in aspect ratio of the nanoparticles produced further reductions in mobility, and this reduction was so significant that tortuous path contribution could not explain it. We expect that percolation of the higher aspect ratio gold nanoparticles (as seen in TEM images) led to preferred conduction through the gold network, and therefore resulted in lower mobility in the buffer. The structure−mobility relationships found here help establish one possible regime for transport of proteins through nanocomposite hydrogels. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100291b [article] Preliminary observations of the role of material morphology on protein - electrophoretic transport in gold nanocomposite hydrogels [texte imprimé] / Jeffery W. Thompson, Auteur ; Holly A. Stretz, Auteur ; Pedro E. Arce, Auteur . - 2011 . - pp. 12104–12110. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12104–12110 Mots-clés : Gold Nanocomposite Résumé : Nanocomposite polymeric hydrogels have potential to play an important role in clinical diagnostics, therapeutic agents, and electroanalytical devices, among other biotechnological applications. However, the relationship between nanocomposite structure (morphology) and transport specifically of proteins has not been systematically described. In this study, polyacrylamide (PAM) nanocomposites have been synthesized containing various compositions and aspect ratios of gold nanoparticles (GNP). These nanocomposite hydrogels have been characterized for morphology, and examined for their ability to change the effective electrophoretic mobility of a model protein, ovum serum albumin (OSA), under a low applied electric field of 6.7 V/cm. Addition of spherical (low aspect ratio) gold nanoparticles reduces the effective mobility of OSA, a result that cannot be explained by the lower effective cross-link density noted in swelling studies. However, the effective mobility of OSA can be predicted using simple tortuous path models, specifically the Lape−Cussler. An increase in aspect ratio of the nanoparticles produced further reductions in mobility, and this reduction was so significant that tortuous path contribution could not explain it. We expect that percolation of the higher aspect ratio gold nanoparticles (as seen in TEM images) led to preferred conduction through the gold network, and therefore resulted in lower mobility in the buffer. The structure−mobility relationships found here help establish one possible regime for transport of proteins through nanocomposite hydrogels. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100291b

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Gradient multilayer films by forced assembly coextrusion / Michael Ponting in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12111–12118 Titre : Gradient multilayer films by forced assembly coextrusion Type de document : texte imprimé Auteurs : Michael Ponting, Auteur ; Tiffani M. Burt, Auteur ; LaShanda T. J. Korley, Auteur Année de publication : 2011 Article en page(s) : pp. 12111–12118 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymer Layer multiplication Résumé : Forced assembly polymer coextrusion utilizes layer multiplication to produce films with tens or thousands of micrometer to nanometer thick layers. The development of novel uneven split layer multiplying dies has produced gradient multilayer films with at least a 10 times difference between the thickest and thinnest layers. Coextrusion through a series of equal and uneven split multiplier dies allows for flexibility in the unique design of layer thickness distributions by: (1) altering the multiplier offset and (2) changing the sequence of a series of uneven split multiplying dies with different splitting ratios. This new technology has created highly reflective, multilayered photonic films with gradient layer thickness distributions exhibiting, as examples, a 600 nm wide reflection band and dual optical reflection bands within a single film. Also, gradient multilayers exhibit unique mechanical behavior. A layer thickness dependent craze to shear banding deformation mechanism was observed. In addition, gradient controlled buckling was observed across a single film due to foaming-induced layer delamination. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100321h [article] Gradient multilayer films by forced assembly coextrusion [texte imprimé] / Michael Ponting, Auteur ; Tiffani M. Burt, Auteur ; LaShanda T. J. Korley, Auteur . - 2011 . - pp. 12111–12118. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12111–12118 Mots-clés : Polymer Layer multiplication Résumé : Forced assembly polymer coextrusion utilizes layer multiplication to produce films with tens or thousands of micrometer to nanometer thick layers. The development of novel uneven split layer multiplying dies has produced gradient multilayer films with at least a 10 times difference between the thickest and thinnest layers. Coextrusion through a series of equal and uneven split multiplier dies allows for flexibility in the unique design of layer thickness distributions by: (1) altering the multiplier offset and (2) changing the sequence of a series of uneven split multiplying dies with different splitting ratios. This new technology has created highly reflective, multilayered photonic films with gradient layer thickness distributions exhibiting, as examples, a 600 nm wide reflection band and dual optical reflection bands within a single film. Also, gradient multilayers exhibit unique mechanical behavior. A layer thickness dependent craze to shear banding deformation mechanism was observed. In addition, gradient controlled buckling was observed across a single film due to foaming-induced layer delamination. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100321h

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Vacancy diffusion with time - dependent length scale / Aaron W. Thornton in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12119–12124 Titre : Vacancy diffusion with time - dependent length scale : an insightful new model for physical aging in polymers Type de document : texte imprimé Auteurs : Aaron W. Thornton, Auteur ; Anita J. Hill, Auteur Année de publication : 2011 Article en page(s) : pp. 12119–12124 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymers Résumé : Physical aging models are reviewed and further developed to describe the physical aging within thin (>100 nm) and ultrathin polymer films ( DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100696t [article] Vacancy diffusion with time - dependent length scale : an insightful new model for physical aging in polymers [texte imprimé] / Aaron W. Thornton, Auteur ; Anita J. Hill, Auteur . - 2011 . - pp. 12119–12124. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12119–12124 Mots-clés : Polymers Résumé : Physical aging models are reviewed and further developed to describe the physical aging within thin (>100 nm) and ultrathin polymer films ( DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100696t

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Synthesis and characterization of phenolphthalein - based poly(arylene ether sulfone) hydrophilic - hydrophobic multiblock copolymers for proton exchange membranes / Ruilan Guo in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12125–12134 Titre : Synthesis and characterization of phenolphthalein - based poly(arylene ether sulfone) hydrophilic - hydrophobic multiblock copolymers for proton exchange membranes Type de document : texte imprimé Auteurs : Ruilan Guo, Auteur ; Ozma Lane, Auteur ; Desmond VanHouten, Auteur Année de publication : 2011 Article en page(s) : pp.12125–12134 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hydrophilic Hydrophobic Copolymers Résumé : Hydrophilic−hydrophobic alternating multiblock poly(arylene ether sulfone) copolymers containing 4,4′-biphenol (BP) or phenolphthalein (PPH) were synthesized via a coupling reaction between phenoxide-terminated hydrophilic oligomers (BPS100 and PPH100) and highly reactive decafluorobiphenyl end-capped hydrophobic oligomers (BPS0 and PPH0). The block length and block combination of copolymers were varied by precisely controlling the molecular weight Mn and end group functionality of oligomers. The resulting hydrophilic−hydrophobic sequenced multiblock copolymers afforded transparent, ductile, and tough membranes by solution casting from DMAc. Membrane properties of these copolymers were characterized including intrinsic viscosity, thermal stabilities, morphology, water uptake, and proton conductivity. Results were compared among copolymers with various block lengths and block types. Proton conductivity measurements revealed that PPH0-BPS100 copolymers having high IEC values showed better performance than copolymers with PPH100 as hydrophilic blocks. Well-defined nanophase separated morphologies of the multiblock copolymers were demonstrated by tapping mode atomic force microscopy (AFM), confirming that the hydrophilic domains provide a pathway for water and proton transport. It was also shown that the volume fraction of hydrophobic/hydrophilic domains, as well as IEC values, played a critical role in determining the morphological structures and thus the proton transport. Preliminary studies on exploring the film drying temperature and annealing effect on the membrane properties were also reported. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100785t [article] Synthesis and characterization of phenolphthalein - based poly(arylene ether sulfone) hydrophilic - hydrophobic multiblock copolymers for proton exchange membranes [texte imprimé] / Ruilan Guo, Auteur ; Ozma Lane, Auteur ; Desmond VanHouten, Auteur . - 2011 . - pp.12125–12134. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12125–12134 Mots-clés : Hydrophilic Hydrophobic Copolymers Résumé : Hydrophilic−hydrophobic alternating multiblock poly(arylene ether sulfone) copolymers containing 4,4′-biphenol (BP) or phenolphthalein (PPH) were synthesized via a coupling reaction between phenoxide-terminated hydrophilic oligomers (BPS100 and PPH100) and highly reactive decafluorobiphenyl end-capped hydrophobic oligomers (BPS0 and PPH0). The block length and block combination of copolymers were varied by precisely controlling the molecular weight Mn and end group functionality of oligomers. The resulting hydrophilic−hydrophobic sequenced multiblock copolymers afforded transparent, ductile, and tough membranes by solution casting from DMAc. Membrane properties of these copolymers were characterized including intrinsic viscosity, thermal stabilities, morphology, water uptake, and proton conductivity. Results were compared among copolymers with various block lengths and block types. Proton conductivity measurements revealed that PPH0-BPS100 copolymers having high IEC values showed better performance than copolymers with PPH100 as hydrophilic blocks. Well-defined nanophase separated morphologies of the multiblock copolymers were demonstrated by tapping mode atomic force microscopy (AFM), confirming that the hydrophilic domains provide a pathway for water and proton transport. It was also shown that the volume fraction of hydrophobic/hydrophilic domains, as well as IEC values, played a critical role in determining the morphological structures and thus the proton transport. Preliminary studies on exploring the film drying temperature and annealing effect on the membrane properties were also reported. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100785t

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Solid-acid-catalyzed esterification of oleic acid assisted by microwave heating / Carlos A. R. Melo Junior in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12135–12139 Titre : Solid-acid-catalyzed esterification of oleic acid assisted by microwave heating Type de document : texte imprimé Auteurs : Carlos A. R. Melo Junior, Auteur ; Carlos E. R. Albuquerque, Auteur ; Juliana S. A. Carneiro, Auteur Année de publication : 2011 Article en page(s) : pp. 12135–12139 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solid acid catalysts Résumé : This work aims to evaluate the activity and stability of solid acid catalysts (niobium oxide and sulfated zirconia) in the methyl esterification of oleic acid assisted by microwave heating, an alternative route to the base-catalyzed transesterification reaction using conventional heating. Both catalysts have yielded similar conversions (68% for Nb2O5 and 68.7% for sulfated zirconia at 200 °C, t = 20 min, methanol-to-fatty acid molar ratio = 10, 5% w/w catalyst), much higher than the one obtained without catalyst (39.3%), besides a small deactivation after the fourth use (3% for Nb2O5, 11% for sulfated zirconia, compared to the first use). The results have not indicated a pronounced increase on reaction conversions by using microwave heating when compared to conventional data found in the literature. However, microwave irradiation remains attractive for heating esterification systems, since it allows for achieving high temperatures at reduced times. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100501d [article] Solid-acid-catalyzed esterification of oleic acid assisted by microwave heating [texte imprimé] / Carlos A. R. Melo Junior, Auteur ; Carlos E. R. Albuquerque, Auteur ; Juliana S. A. Carneiro, Auteur . - 2011 . - pp. 12135–12139. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12135–12139 Mots-clés : Solid acid catalysts Résumé : This work aims to evaluate the activity and stability of solid acid catalysts (niobium oxide and sulfated zirconia) in the methyl esterification of oleic acid assisted by microwave heating, an alternative route to the base-catalyzed transesterification reaction using conventional heating. Both catalysts have yielded similar conversions (68% for Nb2O5 and 68.7% for sulfated zirconia at 200 °C, t = 20 min, methanol-to-fatty acid molar ratio = 10, 5% w/w catalyst), much higher than the one obtained without catalyst (39.3%), besides a small deactivation after the fourth use (3% for Nb2O5, 11% for sulfated zirconia, compared to the first use). The results have not indicated a pronounced increase on reaction conversions by using microwave heating when compared to conventional data found in the literature. However, microwave irradiation remains attractive for heating esterification systems, since it allows for achieving high temperatures at reduced times. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100501d

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Simultaneous removal of SO2 and NOx by calcium hydroxide at low temperature / Guoqing Chen in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12140–12147 Titre : Simultaneous removal of SO2 and NOx by calcium hydroxide at low temperature : effect of SO2 absorption on NO2 removal Type de document : texte imprimé Auteurs : Guoqing Chen, Auteur ; Jihui Gao, Auteur ; Jianmin Gao, Auteur Année de publication : 2011 Article en page(s) : pp.12140–12147 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Calcium Hydroxide Absorption Résumé : A fixed reactor was employed to investigate the influence of SO2 absorption process on NO2 removal by Ca(OH)2 under low-temperature and humid circumstance. The step experiments and pretreatment experiments were carried out to investigate the effect of the desulfurization product CaSO3 on NO2 removal. The roles of gas components (O2, H2O) and reaction temperature in SO2 enhancing NO2 removal were discussed by comparing their influences on NO2 removal in and without the presence of SO2. It is interesting to observe that NOx removal first increases and then decreases with the increase of SO2 concentration. The presence of SO2 in the flue gas was found to restrain NO release and enhance NO2 removal. SO2 removal product CaSO3 did provide an additional reaction path for NO2 removal, but the reaction rate of NO2 and CaSO3 was lower than that of Ca(OH)2 due to the lower solubility of CaSO3. The enhancement effect of SO2 on NO2 removal can be explained by the presence of SO32− and HSO3− ions derived from the hydrolysis of SO2 in the water layer. HSO3− and SO32− reacted with NO2 to form sulfate, which was detected in the spent absorbent by X-ray diffraction. The higher relative humidity can accelerate the hydrolysis of SO2 and the dissolution of Ca(OH)2, which are in favor of NO2 removal. However, the oxidization of SO32− to SO42− by O2 lowers NO2 removal. Reaction temperature has negligible influence on the enhancement of NOx removal by the presence of SO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101594x [article] Simultaneous removal of SO2 and NOx by calcium hydroxide at low temperature : effect of SO2 absorption on NO2 removal [texte imprimé] / Guoqing Chen, Auteur ; Jihui Gao, Auteur ; Jianmin Gao, Auteur . - 2011 . - pp.12140–12147. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12140–12147 Mots-clés : Calcium Hydroxide Absorption Résumé : A fixed reactor was employed to investigate the influence of SO2 absorption process on NO2 removal by Ca(OH)2 under low-temperature and humid circumstance. The step experiments and pretreatment experiments were carried out to investigate the effect of the desulfurization product CaSO3 on NO2 removal. The roles of gas components (O2, H2O) and reaction temperature in SO2 enhancing NO2 removal were discussed by comparing their influences on NO2 removal in and without the presence of SO2. It is interesting to observe that NOx removal first increases and then decreases with the increase of SO2 concentration. The presence of SO2 in the flue gas was found to restrain NO release and enhance NO2 removal. SO2 removal product CaSO3 did provide an additional reaction path for NO2 removal, but the reaction rate of NO2 and CaSO3 was lower than that of Ca(OH)2 due to the lower solubility of CaSO3. The enhancement effect of SO2 on NO2 removal can be explained by the presence of SO32− and HSO3− ions derived from the hydrolysis of SO2 in the water layer. HSO3− and SO32− reacted with NO2 to form sulfate, which was detected in the spent absorbent by X-ray diffraction. The higher relative humidity can accelerate the hydrolysis of SO2 and the dissolution of Ca(OH)2, which are in favor of NO2 removal. However, the oxidization of SO32− to SO42− by O2 lowers NO2 removal. Reaction temperature has negligible influence on the enhancement of NOx removal by the presence of SO2. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101594x

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A novel process to prepare ammonium polyphosphate with crystalline form II and its comparison with melamine polyphosphate / Gousheng Liu in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12148–12155 Titre : A novel process to prepare ammonium polyphosphate with crystalline form II and its comparison with melamine polyphosphate Type de document : texte imprimé Auteurs : Gousheng Liu, Auteur ; Wenyan Chen, Auteur ; Jianguo Yu, Auteur Année de publication : 2011 Article en page(s) : pp. 12148–12155 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ammonium polyphosphate Crystalline Résumé : P4O10 is highly deliquescent and reactive; techniques using non-P4O10 process are not only required for environmental protection, but also for consideration of safety and cost in industrial-scale production. A non-P4O10 process to prepare ammonium polyphosphate with crystalline form II (APP-II) was proposed by heating the mixture of diammonium hydrogen phosphate (DAP) and melamine under wet ammonia. Its water solubility, FT-IR, XRD, and 31P NMR spectra were compared with those of commercial APP-II and melamine polyphosphate (MPoly), and interesting results were obtained. Thermogravometric analysis (TGA) showed the synthesized APP-II had better thermal stability than commercial APP-II. The reaction mechanism and molecular structure for the subject compound were investigated and discussed in detail. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1014102 [article] A novel process to prepare ammonium polyphosphate with crystalline form II and its comparison with melamine polyphosphate [texte imprimé] / Gousheng Liu, Auteur ; Wenyan Chen, Auteur ; Jianguo Yu, Auteur . - 2011 . - pp. 12148–12155. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12148–12155 Mots-clés : Ammonium polyphosphate Crystalline Résumé : P4O10 is highly deliquescent and reactive; techniques using non-P4O10 process are not only required for environmental protection, but also for consideration of safety and cost in industrial-scale production. A non-P4O10 process to prepare ammonium polyphosphate with crystalline form II (APP-II) was proposed by heating the mixture of diammonium hydrogen phosphate (DAP) and melamine under wet ammonia. Its water solubility, FT-IR, XRD, and 31P NMR spectra were compared with those of commercial APP-II and melamine polyphosphate (MPoly), and interesting results were obtained. Thermogravometric analysis (TGA) showed the synthesized APP-II had better thermal stability than commercial APP-II. The reaction mechanism and molecular structure for the subject compound were investigated and discussed in detail. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1014102

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Preliminary study on converting hybrid poplar to high - value chemicals and lignin using organosolv ethanol process / Da-Eun Kim in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12156–12163 Titre : Preliminary study on converting hybrid poplar to high - value chemicals and lignin using organosolv ethanol process Type de document : texte imprimé Auteurs : Da-Eun Kim, Auteur ; Xuejun Pan, Auteur Année de publication : 2011 Article en page(s) : pp. 12156–12163 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Organosolv Ethanol process Résumé : The organosolv ethanol process was adapted for converting hybrid poplar (Populus nigra L. × P. maximowiczii) into organosolv lignin and saccharide-derived chemicals, such as levulinic acid (LA), hydroxymethylfurfural (HMF), and furfural. The effect of process conditions (temperature, ethanol concentration, sulfuric acid dosage, and reaction time) on product yields was investigated using an experimental matrix designed with response surface methodology (RSM) and small Hartley composite design. The conditions ranged over 173−207 °C, 15−66 min, 2.3−5.7% H2SO4 (SA) on oven-dry wood (w/w), and 33−67% ethanol concentration (v/v). Results indicated that temperature, sulfuric acid loading, and their interaction had a significant effect on the yields of lignin and saccharide-derived chemicals. Comparative investigation of the organosolv process and acid process indicated that ethanol not only enhanced the delignification and production of organosolv lignin, but also improved the conversion yields of pentoses to furfural and hexoses to HMF and LA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101671r [article] Preliminary study on converting hybrid poplar to high - value chemicals and lignin using organosolv ethanol process [texte imprimé] / Da-Eun Kim, Auteur ; Xuejun Pan, Auteur . - 2011 . - pp. 12156–12163. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12156–12163 Mots-clés : Organosolv Ethanol process Résumé : The organosolv ethanol process was adapted for converting hybrid poplar (Populus nigra L. × P. maximowiczii) into organosolv lignin and saccharide-derived chemicals, such as levulinic acid (LA), hydroxymethylfurfural (HMF), and furfural. The effect of process conditions (temperature, ethanol concentration, sulfuric acid dosage, and reaction time) on product yields was investigated using an experimental matrix designed with response surface methodology (RSM) and small Hartley composite design. The conditions ranged over 173−207 °C, 15−66 min, 2.3−5.7% H2SO4 (SA) on oven-dry wood (w/w), and 33−67% ethanol concentration (v/v). Results indicated that temperature, sulfuric acid loading, and their interaction had a significant effect on the yields of lignin and saccharide-derived chemicals. Comparative investigation of the organosolv process and acid process indicated that ethanol not only enhanced the delignification and production of organosolv lignin, but also improved the conversion yields of pentoses to furfural and hexoses to HMF and LA. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101671r

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Industrial Production of tert-Butyl-4-oxoazepane-1-carboxylate / Yun-Sheng Huang in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12164–12167 Titre : Industrial Production of tert-Butyl-4-oxoazepane-1-carboxylate Type de document : texte imprimé Auteurs : Yun-Sheng Huang, Auteur ; Wen-Qing Zhang, Auteur ; Pei-Feng Zhang, Auteur Année de publication : 2011 Article en page(s) : pp. 12164–12167 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Oxoazepane Carboxylate Résumé : A large-scale process for the preparation of tert-butyl 4-oxoazepane-1-carboxylate (1), a useful intermediate for many pharmaceutical products under development, is described. This process is based on the ring expansion of tert-butyl piperid-4-one-1-carboxylate using ethyl diazoacetate. The entire process can be operated safely, less expensively, and conveniently without the necessary purification for any of the intermediates. The production scale of over 33 kg of the final product was achieved with good overall yield. The main focuses of optimization were the large-scale preparation of ethyl diazoacetate and the ring expansion at low temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101807g [article] Industrial Production of tert-Butyl-4-oxoazepane-1-carboxylate [texte imprimé] / Yun-Sheng Huang, Auteur ; Wen-Qing Zhang, Auteur ; Pei-Feng Zhang, Auteur . - 2011 . - pp. 12164–12167. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12164–12167 Mots-clés : Oxoazepane Carboxylate Résumé : A large-scale process for the preparation of tert-butyl 4-oxoazepane-1-carboxylate (1), a useful intermediate for many pharmaceutical products under development, is described. This process is based on the ring expansion of tert-butyl piperid-4-one-1-carboxylate using ethyl diazoacetate. The entire process can be operated safely, less expensively, and conveniently without the necessary purification for any of the intermediates. The production scale of over 33 kg of the final product was achieved with good overall yield. The main focuses of optimization were the large-scale preparation of ethyl diazoacetate and the ring expansion at low temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101807g

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Methyl ester production from sunflower and waste cooking oils using alkali - doped metal oxide catalysts / Georgios Karavalakis in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12168–12172 Titre : Methyl ester production from sunflower and waste cooking oils using alkali - doped metal oxide catalysts Type de document : texte imprimé Auteurs : Georgios Karavalakis, Auteur ; Georgios Anastopoulos, Auteur ; Stamos Stournas, Auteur Année de publication : 2011 Article en page(s) : pp.12168–12172 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Methyl ester Metal oxide catalysts Résumé : The purpose of this study was to investigate a series of alkali-doped metal oxide catalysts for their activity in the transesterification of sunflower oil and waste cooking oil with methanol. The metal oxides used as supports were Al2O3 and ZnO loaded with KHCO3 and KNO3, respectively, at various concentrations and calcined at different temperatures. These catalysts appeared to be promising candidates to replace homogeneous catalysts for biodiesel production as the reaction times and catalyst amount are low enough in order to achieve high ester yields. In most cases, the increase in loading concentration favorably influenced oil conversion. On the other hand, at calcination temperatures above 750 °C, a noticeable drop in biodiesel yield was observed which may be ascribed to decomposition effects of the active sites. In general, the use of sunflower oil resulted in higher ester yields when compared to waste cooking oil which was characterized by a high amount of free fatty acids and moisture. Biodiesel ester content was also strongly related with catalyst amount, methanol to oil molar ratio, reaction time, and catalyst reusability. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101270e [article] Methyl ester production from sunflower and waste cooking oils using alkali - doped metal oxide catalysts [texte imprimé] / Georgios Karavalakis, Auteur ; Georgios Anastopoulos, Auteur ; Stamos Stournas, Auteur . - 2011 . - pp.12168–12172. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp.12168–12172 Mots-clés : Methyl ester Metal oxide catalysts Résumé : The purpose of this study was to investigate a series of alkali-doped metal oxide catalysts for their activity in the transesterification of sunflower oil and waste cooking oil with methanol. The metal oxides used as supports were Al2O3 and ZnO loaded with KHCO3 and KNO3, respectively, at various concentrations and calcined at different temperatures. These catalysts appeared to be promising candidates to replace homogeneous catalysts for biodiesel production as the reaction times and catalyst amount are low enough in order to achieve high ester yields. In most cases, the increase in loading concentration favorably influenced oil conversion. On the other hand, at calcination temperatures above 750 °C, a noticeable drop in biodiesel yield was observed which may be ascribed to decomposition effects of the active sites. In general, the use of sunflower oil resulted in higher ester yields when compared to waste cooking oil which was characterized by a high amount of free fatty acids and moisture. Biodiesel ester content was also strongly related with catalyst amount, methanol to oil molar ratio, reaction time, and catalyst reusability. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101270e

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Process analysis on photocatalyzed dye decomposition for water treatment with TiO2 - coated rotating disk reactor / Chih-Yi Chang in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12173–12179 Titre : Process analysis on photocatalyzed dye decomposition for water treatment with TiO2 - coated rotating disk reactor Type de document : texte imprimé Auteurs : Chih-Yi Chang, Auteur ; Nae-Lih Wu, Auteur Année de publication : 2011 Article en page(s) : pp. 12173–12179 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Photocatalyzed Water treatment Résumé : Wastewater treatment based on solar energy effected photocatalytic reaction is a green process that utilizes renewable energy resources and minimizes secondary pollution. Low conversion efficiency is one of the key issues to overcome for realizing its practical application. With an aim at significantly raising the process efficiency, a rotating disk reactor (RDR) has been evaluated for the application of photocatalytic decomposition of dye pollutants in water. In this process, photocatalyst (TiO2) particles are immobilized onto a disk (6 cm in diameter), and dye (methyl orange)-containing solution is allowed to flow in radial direction along the surface of the disk, which is rotating and illuminated with UV light. The correlations between the fundamental characteristics of the reactor, including residence time and film thickness, and its operating variables, including volumetric flow rate and disk rotating speed, have been established by the combination of fluid dynamic and kinetic models. The results indicate that the reactor can be operating beyond mass-transfer limitation by reducing the liquid film thickness, which is a complex function of both flow rate and disk rotating speed, below certain critical value. Even under such a condition, the overall reaction rate remains strongly affected by the liquid film thickness due to the intensity attenuation of incidence light through the liquid film before reaching the TiO2 surface. With selected operation conditions, conversions greater than 50% have been achieved within only a few seconds of residence time. A reactor design equation has been derived, indicating promising scale-up potential of the process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101330n [article] Process analysis on photocatalyzed dye decomposition for water treatment with TiO2 - coated rotating disk reactor [texte imprimé] / Chih-Yi Chang, Auteur ; Nae-Lih Wu, Auteur . - 2011 . - pp. 12173–12179. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12173–12179 Mots-clés : Photocatalyzed Water treatment Résumé : Wastewater treatment based on solar energy effected photocatalytic reaction is a green process that utilizes renewable energy resources and minimizes secondary pollution. Low conversion efficiency is one of the key issues to overcome for realizing its practical application. With an aim at significantly raising the process efficiency, a rotating disk reactor (RDR) has been evaluated for the application of photocatalytic decomposition of dye pollutants in water. In this process, photocatalyst (TiO2) particles are immobilized onto a disk (6 cm in diameter), and dye (methyl orange)-containing solution is allowed to flow in radial direction along the surface of the disk, which is rotating and illuminated with UV light. The correlations between the fundamental characteristics of the reactor, including residence time and film thickness, and its operating variables, including volumetric flow rate and disk rotating speed, have been established by the combination of fluid dynamic and kinetic models. The results indicate that the reactor can be operating beyond mass-transfer limitation by reducing the liquid film thickness, which is a complex function of both flow rate and disk rotating speed, below certain critical value. Even under such a condition, the overall reaction rate remains strongly affected by the liquid film thickness due to the intensity attenuation of incidence light through the liquid film before reaching the TiO2 surface. With selected operation conditions, conversions greater than 50% have been achieved within only a few seconds of residence time. A reactor design equation has been derived, indicating promising scale-up potential of the process. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101330n

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Ru(II) phenanthroline complex as catalyst for chemoselective hydrogenation of nitro - aryls in a green process / Amit A. Deshmukh in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12180–12184 Titre : Ru(II) phenanthroline complex as catalyst for chemoselective hydrogenation of nitro - aryls in a green process Type de document : texte imprimé Auteurs : Amit A. Deshmukh, Auteur ; Atul K. Prashar, Auteur ; Anil K. Kinage, Auteur Année de publication : 2011 Article en page(s) : pp. 12180–12184 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Hydrogenation Résumé : Ru(II) Phenanthroline [Ru(II)(Phen)n where n = 1,2,3] complexes were used as highly chemoselective catalysts for hydrogenation of nitro aryls using molecular hydrogen in an aqueous media. Water, universal solvent, was used as a reaction mixture for hydrogenation of nitro-aryls to make the process green. The chemoselectivity in hydrogenation of substituted nitrobenzene to substituted aniline was obtained as high as >99% at about complete conversion of substituted nitrobenzene. The parametric effects, including effect of solvent, effect of ligand, effect of metal to ligand ratio, effect of temperature and pressure, were studied in detail to obtain the best results. The Ru(Phen)n was characterized by FTIR, UV−vis, and XPS. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1015969 [article] Ru(II) phenanthroline complex as catalyst for chemoselective hydrogenation of nitro - aryls in a green process [texte imprimé] / Amit A. Deshmukh, Auteur ; Atul K. Prashar, Auteur ; Anil K. Kinage, Auteur . - 2011 . - pp. 12180–12184. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12180–12184 Mots-clés : Catalyst Hydrogenation Résumé : Ru(II) Phenanthroline [Ru(II)(Phen)n where n = 1,2,3] complexes were used as highly chemoselective catalysts for hydrogenation of nitro aryls using molecular hydrogen in an aqueous media. Water, universal solvent, was used as a reaction mixture for hydrogenation of nitro-aryls to make the process green. The chemoselectivity in hydrogenation of substituted nitrobenzene to substituted aniline was obtained as high as >99% at about complete conversion of substituted nitrobenzene. The parametric effects, including effect of solvent, effect of ligand, effect of metal to ligand ratio, effect of temperature and pressure, were studied in detail to obtain the best results. The Ru(Phen)n was characterized by FTIR, UV−vis, and XPS. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1015969

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Effects of dissolved organic compounds and electrolyte on precipitated calcium carbonate retention in papermaking / Sedat Ondaral in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12185–12190 Titre : Effects of dissolved organic compounds and electrolyte on precipitated calcium carbonate retention in papermaking Type de document : texte imprimé Auteurs : Sedat Ondaral, Auteur ; Mustafa Usta, Auteur Année de publication : 2011 Article en page(s) : pp. 12185–12190 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Organic compounds Electrolyte Résumé : The reuse of process water in paper mills causes increase in the concentration of contaminants such as dissolved and colloidal substances (DCS) and electrolyte in the suspension. In this study, the effect of these materials on the retention of precipitated calcium carbonate (PCC) was investigated. The cationic microgels (CMG) with low charge density and cross-linked structure were compared to linear poly-DADMAC with higher charge density in the different model white water systems (WWS) including different concentrations of DCS and electrolyte. The results indicated that the main mechanism behind PCC retention for these two kinds of polyelectrolyte was patch-type electrostatic interaction in less and medium contaminated WWSs. On the other hand, a nonionic interaction was found in the highly contaminated WWS. It was also determined that PCC retention decreased with increasing contaminant concentration. CMG2 was less influenced by the contaminants because it had lower charge density and more stable and cross-linked structure as compared to CMG1 and poly-DADMAC. Additionally, SEM photos showed that PCC retention took place with bigger PCC flocks in the medium contaminated water. Yet, the flock size decreased with further increase of contaminant concentration. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001718 [article] Effects of dissolved organic compounds and electrolyte on precipitated calcium carbonate retention in papermaking [texte imprimé] / Sedat Ondaral, Auteur ; Mustafa Usta, Auteur . - 2011 . - pp. 12185–12190. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12185–12190 Mots-clés : Organic compounds Electrolyte Résumé : The reuse of process water in paper mills causes increase in the concentration of contaminants such as dissolved and colloidal substances (DCS) and electrolyte in the suspension. In this study, the effect of these materials on the retention of precipitated calcium carbonate (PCC) was investigated. The cationic microgels (CMG) with low charge density and cross-linked structure were compared to linear poly-DADMAC with higher charge density in the different model white water systems (WWS) including different concentrations of DCS and electrolyte. The results indicated that the main mechanism behind PCC retention for these two kinds of polyelectrolyte was patch-type electrostatic interaction in less and medium contaminated WWSs. On the other hand, a nonionic interaction was found in the highly contaminated WWS. It was also determined that PCC retention decreased with increasing contaminant concentration. CMG2 was less influenced by the contaminants because it had lower charge density and more stable and cross-linked structure as compared to CMG1 and poly-DADMAC. Additionally, SEM photos showed that PCC retention took place with bigger PCC flocks in the medium contaminated water. Yet, the flock size decreased with further increase of contaminant concentration. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1001718

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Increasing the productivity of colloidal zeolite beta by posthydrolysis evaporation / Shun-Yi Fang in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12191–12196 Titre : Increasing the productivity of colloidal zeolite beta by posthydrolysis evaporation Type de document : texte imprimé Auteurs : Shun-Yi Fang, Auteur ; Anthony S. T. Chiang, Auteur ; Hsien-Ming Kao, Auteur Année de publication : 2011 Article en page(s) : pp. 12191–12196 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Zeolite Résumé : Colloidal beta zeolite is typically synthesized by the reaction of a clear precursor sol at temperatures below 100 °C. The process usually suffers from limited batch productivity with a long reaction time, because of the large amount of water used in the precursor sol. Reducing the water content is expected to shorten the reaction time, enhance the productivity, and reduce the particle size, but proper procedures are required to achieve a supersaturated, but pourable, composition. A precursor sol having a record low H2O/SiO2 ratio has been prepared by the addition of a posthydrolysis evaporation step. Compared to a conventional composition, which took 14 days to produce >100-nm particles at 60% yield of 55-nm redispersible zeolite beta particles in only 6 days. The formation of beta zeolite and the evolution of its particle size during the 90 °C reaction confirmed that aggregation always occurred before colloidal zeolite particles could be extracted. On the other hand, the “amorphous” residue was also found to be microporous, suggesting that it might be smaller zeolite particles that were undetectable by XRD and did not settle even with the high-speed centrifugation employed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100796d [article] Increasing the productivity of colloidal zeolite beta by posthydrolysis evaporation [texte imprimé] / Shun-Yi Fang, Auteur ; Anthony S. T. Chiang, Auteur ; Hsien-Ming Kao, Auteur . - 2011 . - pp. 12191–12196. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12191–12196 Mots-clés : Zeolite Résumé : Colloidal beta zeolite is typically synthesized by the reaction of a clear precursor sol at temperatures below 100 °C. The process usually suffers from limited batch productivity with a long reaction time, because of the large amount of water used in the precursor sol. Reducing the water content is expected to shorten the reaction time, enhance the productivity, and reduce the particle size, but proper procedures are required to achieve a supersaturated, but pourable, composition. A precursor sol having a record low H2O/SiO2 ratio has been prepared by the addition of a posthydrolysis evaporation step. Compared to a conventional composition, which took 14 days to produce >100-nm particles at 60% yield of 55-nm redispersible zeolite beta particles in only 6 days. The formation of beta zeolite and the evolution of its particle size during the 90 °C reaction confirmed that aggregation always occurred before colloidal zeolite particles could be extracted. On the other hand, the “amorphous” residue was also found to be microporous, suggesting that it might be smaller zeolite particles that were undetectable by XRD and did not settle even with the high-speed centrifugation employed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100796d

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Crystallization of spherical common salt in the submillimeter size range without habit modifier / Indrajit Mukhopadhyay in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12197–12203 Titre : Crystallization of spherical common salt in the submillimeter size range without habit modifier Type de document : texte imprimé Auteurs : Indrajit Mukhopadhyay, Auteur ; Vadake. P. Mohandas, Auteur ; Girish R. Desale, Auteur Année de publication : 2011 Article en page(s) : pp. 12197–12203 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Crystallization Spherical Résumé : Nearly spherical morphology of solution-grown NaCl particles in the size range of 300−1000 μm was achieved at 55−60 °C employing a suitable crystallizer equipped with a butterfly wing-shaped impeller operated at 250 rpm. Morphology control was equally effective with synthetic and natural brines and required no habit modifier. Sieved spherical salt of 350−500 μm size exhibited superior flow (ca. 20% greater mass flow rate through a funnel; angle of repose 16°)—as compared to commercial vacuum evaporated free flow cubic salt of comparable dimension—upon treatment with potassium ferrocyanide anticaking additive. The superior flow characteristic was retained even after 3 months of storage. Scanning electron microscopic studies revealed that the round polycrystalline particles were derived from the stacking of minute NaCl cubes and the average size of the spheres was amenable to reduction through use of ethanol as antisolvent. The process was successfully scaled up to 10 kg level. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1016317 [article] Crystallization of spherical common salt in the submillimeter size range without habit modifier [texte imprimé] / Indrajit Mukhopadhyay, Auteur ; Vadake. P. Mohandas, Auteur ; Girish R. Desale, Auteur . - 2011 . - pp. 12197–12203. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12197–12203 Mots-clés : Crystallization Spherical Résumé : Nearly spherical morphology of solution-grown NaCl particles in the size range of 300−1000 μm was achieved at 55−60 °C employing a suitable crystallizer equipped with a butterfly wing-shaped impeller operated at 250 rpm. Morphology control was equally effective with synthetic and natural brines and required no habit modifier. Sieved spherical salt of 350−500 μm size exhibited superior flow (ca. 20% greater mass flow rate through a funnel; angle of repose 16°)—as compared to commercial vacuum evaporated free flow cubic salt of comparable dimension—upon treatment with potassium ferrocyanide anticaking additive. The superior flow characteristic was retained even after 3 months of storage. Scanning electron microscopic studies revealed that the round polycrystalline particles were derived from the stacking of minute NaCl cubes and the average size of the spheres was amenable to reduction through use of ethanol as antisolvent. The process was successfully scaled up to 10 kg level. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1016317

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Synthesis and characterization of paraffin wax microcapsules with acrylic - based polymer shells / Luz Sanchez-Silva in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12204–12211 Titre : Synthesis and characterization of paraffin wax microcapsules with acrylic - based polymer shells Type de document : texte imprimé Auteurs : Luz Sanchez-Silva, Auteur ; John Tsavalas, Auteur ; Donald Sundberg, Auteur Année de publication : 2011 Article en page(s) : pp. 12204–12211 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microcapsules Polymer Résumé : Microencapsulation of PRS paraffin wax was carried out by means of suspension-like homopolymerization of methyl methacrylate (MMA) and by the copolymerization of this monomer with methyl acrylate (MA) and methacrylic acid (MAA). The influence of the type of monomers and their proportion as shell materials, the mass ratio of polyvinylpyrrolidone to monomers (PVP/monomers), and the mass ratio of PRS paraffin wax to monomers (PRS/monomers) on the properties of phase change material (PCM) microcapsules has been studied. The analytical techniques used for the characterization of the particles were differential scanning calorimetry (DSC) and modulated DSC, dynamic light scattering, environmental scanning electron microscopy (ESEM) and gel permeation chromatography (GPC). The chemical property differences between the encapsulating “shell” material, acrylic polymer in this case, compared to the “core” material (PRS paraffin wax), such as polarity and interfacial tensions, largely determine the thermodynamically favored morphology of the microcapsules. While the equilibrium morphology was a core/shell structure, kinetic factors relating to the competition between the fast acrylic polymerization rate and the diffusion limited rate of phase separation were found to constrain the ability of the system to approach that equilibrium structure. For both homopolymerization of methyl methacrylate (PMMA) and copolymerizations of methyl methacrylate with methyl acrylate (P(MMA-co-MA)), “pomegranate” microspheres were observed with a thin acrylic shell surrounding an inner composite structure constituted by a paraffin matrix with a dense assortment of PMMA spherical domains. Ter-polymerizations incorporating methacrylic acid (P(MMA-co-MA-co-MAA) had a remarkable effect on the morphology and average particle size, resulting again in “pomegranate” microparticles but where the internal PMMA spheroids were more densely populated closer to the outer portion of the capsule; approaching a core/shell structure. As the amount of polyvinylpyrrolidone stabilizer in the aqueous medium was increased and the PRS/monomers proportion was decreased, the mean particle size of the microcapsules decreased. However, higher PVP/monomer and PRS/monomer ratios led to less efficient encapsulation of the PRS paraffin wax. Near perfect encapsulation efficiency was obtained for two pairings of these ratios via P(MMA-co-MA-co-MAA) polymerization, but only up to an equal mass ratio of PRS to acrylic polymer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101727b [article] Synthesis and characterization of paraffin wax microcapsules with acrylic - based polymer shells [texte imprimé] / Luz Sanchez-Silva, Auteur ; John Tsavalas, Auteur ; Donald Sundberg, Auteur . - 2011 . - pp. 12204–12211. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12204–12211 Mots-clés : Microcapsules Polymer Résumé : Microencapsulation of PRS paraffin wax was carried out by means of suspension-like homopolymerization of methyl methacrylate (MMA) and by the copolymerization of this monomer with methyl acrylate (MA) and methacrylic acid (MAA). The influence of the type of monomers and their proportion as shell materials, the mass ratio of polyvinylpyrrolidone to monomers (PVP/monomers), and the mass ratio of PRS paraffin wax to monomers (PRS/monomers) on the properties of phase change material (PCM) microcapsules has been studied. The analytical techniques used for the characterization of the particles were differential scanning calorimetry (DSC) and modulated DSC, dynamic light scattering, environmental scanning electron microscopy (ESEM) and gel permeation chromatography (GPC). The chemical property differences between the encapsulating “shell” material, acrylic polymer in this case, compared to the “core” material (PRS paraffin wax), such as polarity and interfacial tensions, largely determine the thermodynamically favored morphology of the microcapsules. While the equilibrium morphology was a core/shell structure, kinetic factors relating to the competition between the fast acrylic polymerization rate and the diffusion limited rate of phase separation were found to constrain the ability of the system to approach that equilibrium structure. For both homopolymerization of methyl methacrylate (PMMA) and copolymerizations of methyl methacrylate with methyl acrylate (P(MMA-co-MA)), “pomegranate” microspheres were observed with a thin acrylic shell surrounding an inner composite structure constituted by a paraffin matrix with a dense assortment of PMMA spherical domains. Ter-polymerizations incorporating methacrylic acid (P(MMA-co-MA-co-MAA) had a remarkable effect on the morphology and average particle size, resulting again in “pomegranate” microparticles but where the internal PMMA spheroids were more densely populated closer to the outer portion of the capsule; approaching a core/shell structure. As the amount of polyvinylpyrrolidone stabilizer in the aqueous medium was increased and the PRS/monomers proportion was decreased, the mean particle size of the microcapsules decreased. However, higher PVP/monomer and PRS/monomer ratios led to less efficient encapsulation of the PRS paraffin wax. Near perfect encapsulation efficiency was obtained for two pairings of these ratios via P(MMA-co-MA-co-MAA) polymerization, but only up to an equal mass ratio of PRS to acrylic polymer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101727b

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Carbonation behavior of K2CO3 with different microstructure used as an active component of dry sorbents for CO2 capture / Chuanwen Zhao in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12212-12216 Titre : Carbonation behavior of K2CO3 with different microstructure used as an active component of dry sorbents for CO2 capture Type de document : texte imprimé Auteurs : Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur Année de publication : 2011 Article en page(s) : pp. 12212-12216 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Carbon dioxide Microstructure Carbonation Résumé : To choose the proper active component for potassium-based sorbents to capture CO2, the carbonation behavior of some potassium carbonate from different sources was investigated with thermogravimetric analysis (TGA) and a fixed-bed reactor. The results show that the carbonation reaction process and the reaction rate of the samples are different, although their crystal structures and elemental compositions are the same. K2CO3 calcined from KHCO3 shows excellent carbonation capacity through producing the active species of K4H2(CO3)3·1.5H2O The dimensionless weight increased to 1.36 in 27.7 min in TGA, corresponding to 80.2% conversion of the K2CO3 to KHCO3. The amount of CO2 capture reached 6.74 mol/(kg sorbent) within 23.3 min, corresponding to 93.0% conversion of the K2CO3 to KHCO3. The reason is that the particle morphologies of those sorbents are different: the surface area and pore volume of K2CO3 calcined from KHCO3 are the highest, and the porc distribution range is wider than that of other samples. Therefore, it is better to load potassium carbonate one? a support with a large surface area and pore volume, to improve the CO2 capture capacity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463385 [article] Carbonation behavior of K2CO3 with different microstructure used as an active component of dry sorbents for CO2 capture [texte imprimé] / Chuanwen Zhao, Auteur ; Xiaoping Chen, Auteur ; Changsui Zhao, Auteur . - 2011 . - pp. 12212-12216. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12212-12216 Mots-clés : Carbon dioxide Microstructure Carbonation Résumé : To choose the proper active component for potassium-based sorbents to capture CO2, the carbonation behavior of some potassium carbonate from different sources was investigated with thermogravimetric analysis (TGA) and a fixed-bed reactor. The results show that the carbonation reaction process and the reaction rate of the samples are different, although their crystal structures and elemental compositions are the same. K2CO3 calcined from KHCO3 shows excellent carbonation capacity through producing the active species of K4H2(CO3)3·1.5H2O The dimensionless weight increased to 1.36 in 27.7 min in TGA, corresponding to 80.2% conversion of the K2CO3 to KHCO3. The amount of CO2 capture reached 6.74 mol/(kg sorbent) within 23.3 min, corresponding to 93.0% conversion of the K2CO3 to KHCO3. The reason is that the particle morphologies of those sorbents are different: the surface area and pore volume of K2CO3 calcined from KHCO3 are the highest, and the porc distribution range is wider than that of other samples. Therefore, it is better to load potassium carbonate one? a support with a large surface area and pore volume, to improve the CO2 capture capacity. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463385

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The dechromatation step in wastewater treatment plants / Giuseppe Trunfio in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12217–12223 Titre : The dechromatation step in wastewater treatment plants : fundamental role and optimization Type de document : texte imprimé Auteurs : Giuseppe Trunfio, Auteur ; Gregorio Crini, Auteur Année de publication : 2011 Article en page(s) : pp. 12217–12223 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Wastewater treatment Dechromatation Optimization Résumé : Chromium compounds represent an important class of chemicals and are widely used in many industrial processes. Their release in the aquatic environment constitutes a concerning source of toxicity for flora and fauna. Chromium exists mainly in the trivalent and hexavalent forms, with the latter being much more soluble and toxic and requiring specific treatment before discharge. A review of the literature data reveals that there are few treatment methods applicable on an industrial scale, mainly because of efficiency and maintenance issues. Among them, the reduction at acidic pH by NaHSO3 and the further precipitation of the more insoluble Cr3+ species formed at neutral pH is the most employed technique, given the opportunity to automatically monitor the reaction by means of simple pH and ORP sensors. On this account, we optimized the setting of pH and ORP parameters, applying the method to synthetic solutions and real industrial wastewater from surface-treatment industries. The experimental results showed that optimization of the parameters (i.e., pH = 2.5 and ORP = 280 mV) leads to a reduction of reducing agent employment and fewer chemical compounds in the solution and final sludge. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101042a [article] The dechromatation step in wastewater treatment plants : fundamental role and optimization [texte imprimé] / Giuseppe Trunfio, Auteur ; Gregorio Crini, Auteur . - 2011 . - pp. 12217–12223. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12217–12223 Mots-clés : Wastewater treatment Dechromatation Optimization Résumé : Chromium compounds represent an important class of chemicals and are widely used in many industrial processes. Their release in the aquatic environment constitutes a concerning source of toxicity for flora and fauna. Chromium exists mainly in the trivalent and hexavalent forms, with the latter being much more soluble and toxic and requiring specific treatment before discharge. A review of the literature data reveals that there are few treatment methods applicable on an industrial scale, mainly because of efficiency and maintenance issues. Among them, the reduction at acidic pH by NaHSO3 and the further precipitation of the more insoluble Cr3+ species formed at neutral pH is the most employed technique, given the opportunity to automatically monitor the reaction by means of simple pH and ORP sensors. On this account, we optimized the setting of pH and ORP parameters, applying the method to synthetic solutions and real industrial wastewater from surface-treatment industries. The experimental results showed that optimization of the parameters (i.e., pH = 2.5 and ORP = 280 mV) leads to a reduction of reducing agent employment and fewer chemical compounds in the solution and final sludge. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101042a

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Design and control of a methyl acetate process using carbonylation of dimethyl ether / R. Bertrum Diemer in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12224–12241 Titre : Design and control of a methyl acetate process using carbonylation of dimethyl ether Type de document : texte imprimé Auteurs : R. Bertrum Diemer, Auteur ; William L. Luyben, Auteur Année de publication : 2011 Article en page(s) : pp. 12224–12241 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Methyl Acetate process Résumé : The production of methyl acetate from the raw materials of methanol and carbon monoxide offers a potentially attractive alternative to other routes. The process has two distinct reaction and separation steps. First, methanol is dehydrated to form dimethyl ether (DME). Then carbon monoxide is combined with DME to produce methyl acetate. Each section involves reactors and distillation columns with either liquid or gas recycle. The purpose of this paper is to develop the economically optimum design of the two-step process and to study its dynamic control. The economics consider capital costs (reactors, distillation columns, heat exchangers, and compressors), energy costs (compressor work, reboiler heat input, and condenser refrigeration), the value of steam produced from the exothermic reactions, the cost of the carbon monoxide, and the heating value of a vent stream that is necessary for purging off the inert hydrogen that enters in the fresh carbon monoxide feed. The process illustrates a number of important design trade-offs among the many design optimization variables: reactor temperatures, reactor pressures, distillation column pressures, reactor sizes and purge composition. A plantwide control structure is developed for the entire two-section process that is capable of effectively handling large disturbances in production rate and fresh feed compositions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101583j [article] Design and control of a methyl acetate process using carbonylation of dimethyl ether [texte imprimé] / R. Bertrum Diemer, Auteur ; William L. Luyben, Auteur . - 2011 . - pp. 12224–12241. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12224–12241 Mots-clés : Methyl Acetate process Résumé : The production of methyl acetate from the raw materials of methanol and carbon monoxide offers a potentially attractive alternative to other routes. The process has two distinct reaction and separation steps. First, methanol is dehydrated to form dimethyl ether (DME). Then carbon monoxide is combined with DME to produce methyl acetate. Each section involves reactors and distillation columns with either liquid or gas recycle. The purpose of this paper is to develop the economically optimum design of the two-step process and to study its dynamic control. The economics consider capital costs (reactors, distillation columns, heat exchangers, and compressors), energy costs (compressor work, reboiler heat input, and condenser refrigeration), the value of steam produced from the exothermic reactions, the cost of the carbon monoxide, and the heating value of a vent stream that is necessary for purging off the inert hydrogen that enters in the fresh carbon monoxide feed. The process illustrates a number of important design trade-offs among the many design optimization variables: reactor temperatures, reactor pressures, distillation column pressures, reactor sizes and purge composition. A plantwide control structure is developed for the entire two-section process that is capable of effectively handling large disturbances in production rate and fresh feed compositions. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101583j

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Calculation of pressure − temperature diagrams and distance for phase transition in polyethylene solutions / G. M. N. Costa in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12242-12253 Titre : Calculation of pressure − temperature diagrams and distance for phase transition in polyethylene solutions Type de document : texte imprimé Auteurs : G. M. N. Costa, Auteur ; S. Kislansky, Auteur ; Y. Guerrieri, Auteur Année de publication : 2011 Article en page(s) : pp. 12242-12253 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Phase transitions Résumé : Understanding the phase behavior of polymer solutions is of great theoretical and practical importance. Pressure versus temperature (P-T) isopleths allow one to determine the number of phases present at a given T, P, and overall mixture composition. In this work, the PC-SAFT (perturbed-chain statistical associating fluid theory) equation of state (EOS) was applied to simulate the curves that describe the boundaries between several distinct regions depicted in P—T isopleths. A new strategy was used, and the simulation results were found to show good agreement with experimental cloud-point isopleth data from the literature. In addition, a method was developed to calculate the distance between an operating point (pressure and temperature) and the corresponding point in the interface for fixed molecular weight and weight fraction of the polymer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463388 [article] Calculation of pressure − temperature diagrams and distance for phase transition in polyethylene solutions [texte imprimé] / G. M. N. Costa, Auteur ; S. Kislansky, Auteur ; Y. Guerrieri, Auteur . - 2011 . - pp. 12242-12253. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12242-12253 Mots-clés : Phase transitions Résumé : Understanding the phase behavior of polymer solutions is of great theoretical and practical importance. Pressure versus temperature (P-T) isopleths allow one to determine the number of phases present at a given T, P, and overall mixture composition. In this work, the PC-SAFT (perturbed-chain statistical associating fluid theory) equation of state (EOS) was applied to simulate the curves that describe the boundaries between several distinct regions depicted in P—T isopleths. A new strategy was used, and the simulation results were found to show good agreement with experimental cloud-point isopleth data from the literature. In addition, a method was developed to calculate the distance between an operating point (pressure and temperature) and the corresponding point in the interface for fixed molecular weight and weight fraction of the polymer. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463388

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Synthesis and characterization of iron (III) - coordinated amine - modified poly (glycidylmethacrylate) - grafted densified cellulose and its applicability in defluoridation from industry effluents / Thayyath S. Anirudhan in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12254–12262 Titre : Synthesis and characterization of iron (III) - coordinated amine - modified poly (glycidylmethacrylate) - grafted densified cellulose and its applicability in defluoridation from industry effluents Type de document : texte imprimé Auteurs : Thayyath S. Anirudhan, Auteur ; Padmajan S. Suchithra, Auteur Année de publication : 2011 Article en page(s) : pp. 12254–12262 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Iron Poly Industry effluents Résumé : In this study, the development and characterization of a novel adsorbent, iron(III)-coordinated amine-modified poly(glycidylmethacrylate)-grafted densified cellulose (AM-Fe-PGDC), for the removal and recovery of fluoride ions from aqueous solutions is reported. The adsorbent was characterized by FTIR, X-ray diffraction, SEM, TG/DTG, surface area analyzer, and potentiometric titration. The effect of process parameters such as agitation time, concentration, pH, ionic strength, adsorbent dose, and temperature on the extent of fluoride adsorption was investigated. The adsorbent exhibits very high adsorption potential (>99.9%) at an optimum equilibrium pH 7.0. The nonlinear form of a pseudo second-order kinetic model and Langmuir isotherm model adequately described the experimental kinetic and equilibrium data. The thermodynamic parameters showed that the adsorption of fluoride onto AM-Fe-PGDC was feasible, spontaneous, and exothermic. Adsorption experiments were also conducted using a commercial anion exchanger, Duolite-A7, for comparison. Utility of the adsorbent was tested with a simulated industry wastewater sample. Adsorbed fluoride ions were desorbed effectively by 0.1 M HCl. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100809f [article] Synthesis and characterization of iron (III) - coordinated amine - modified poly (glycidylmethacrylate) - grafted densified cellulose and its applicability in defluoridation from industry effluents [texte imprimé] / Thayyath S. Anirudhan, Auteur ; Padmajan S. Suchithra, Auteur . - 2011 . - pp. 12254–12262. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12254–12262 Mots-clés : Iron Poly Industry effluents Résumé : In this study, the development and characterization of a novel adsorbent, iron(III)-coordinated amine-modified poly(glycidylmethacrylate)-grafted densified cellulose (AM-Fe-PGDC), for the removal and recovery of fluoride ions from aqueous solutions is reported. The adsorbent was characterized by FTIR, X-ray diffraction, SEM, TG/DTG, surface area analyzer, and potentiometric titration. The effect of process parameters such as agitation time, concentration, pH, ionic strength, adsorbent dose, and temperature on the extent of fluoride adsorption was investigated. The adsorbent exhibits very high adsorption potential (>99.9%) at an optimum equilibrium pH 7.0. The nonlinear form of a pseudo second-order kinetic model and Langmuir isotherm model adequately described the experimental kinetic and equilibrium data. The thermodynamic parameters showed that the adsorption of fluoride onto AM-Fe-PGDC was feasible, spontaneous, and exothermic. Adsorption experiments were also conducted using a commercial anion exchanger, Duolite-A7, for comparison. Utility of the adsorbent was tested with a simulated industry wastewater sample. Adsorbed fluoride ions were desorbed effectively by 0.1 M HCl. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100809f

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Discriminatory analysis of marine - engine lubricants using hopane biomarkers / Masato Taki in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12263–12268 Titre : Discriminatory analysis of marine - engine lubricants using hopane biomarkers Type de document : texte imprimé Auteurs : Masato Taki, Auteur ; Masatoshi Nagai, Auteur Année de publication : 2011 Article en page(s) : pp. 12263–12268 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Engine lubricants Hopane biomarkers Résumé : Twenty marine-engine lubricants from five Japanese oil companies were discriminated on the basis on a hopane analysis using a gas chromatograph−mass spectrometer (GC−MS). The hopane ratios of 18α-22,29,30-trisnorneohopane (1) to 17α-22,29,30-trisnorhopane (2) and of 17α-21β(H)-norhopane (3) to 17α-21β(H)-hopane (5) were determined. Each lubricant can be discriminated by combining the figures represented by the 1 to 2 and 3 to 5 ratios and principal component analysis from 1 through (22R)-17α-21β(H)-29-pentakishomohopane (15). Oleanane (4), one of the biomarkers inherent in the crude oils from Southeast Asia, has been detected in the lubricants of eight out of 20 types, and 4 represents a significant feature for the discrimination. The discrimination of the lubricants in the spilled oils was also investigated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100904b [article] Discriminatory analysis of marine - engine lubricants using hopane biomarkers [texte imprimé] / Masato Taki, Auteur ; Masatoshi Nagai, Auteur . - 2011 . - pp. 12263–12268. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12263–12268 Mots-clés : Engine lubricants Hopane biomarkers Résumé : Twenty marine-engine lubricants from five Japanese oil companies were discriminated on the basis on a hopane analysis using a gas chromatograph−mass spectrometer (GC−MS). The hopane ratios of 18α-22,29,30-trisnorneohopane (1) to 17α-22,29,30-trisnorhopane (2) and of 17α-21β(H)-norhopane (3) to 17α-21β(H)-hopane (5) were determined. Each lubricant can be discriminated by combining the figures represented by the 1 to 2 and 3 to 5 ratios and principal component analysis from 1 through (22R)-17α-21β(H)-29-pentakishomohopane (15). Oleanane (4), one of the biomarkers inherent in the crude oils from Southeast Asia, has been detected in the lubricants of eight out of 20 types, and 4 represents a significant feature for the discrimination. The discrimination of the lubricants in the spilled oils was also investigated. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100904b

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Formation of a Ca12Al14O33 nanolayer and its effect on the attrition behavior of CO2 - adsorbent microspheres composed of CaO nanoparticles / Su F. Wu in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12269–12275 Titre : Formation of a Ca12Al14O33 nanolayer and its effect on the attrition behavior of CO2 - adsorbent microspheres composed of CaO nanoparticles Type de document : texte imprimé Auteurs : Su F. Wu, Auteur ; Ming Z. Jiang, Auteur Année de publication : 2011 Article en page(s) : pp. 12269–12275 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Nanolayer Microspheres Nanoparticles Résumé : The attrition behavior of microspheres composed of CaO nanoparticles that were used as high-temperature CO2-reactive adsorbents was investigated. The nano-CaO/Al2O3 microsphere adsorbents were prepared by a spray technique from a slurry containing a precursor of CaCO3 nanoparticles and an aluminum oxide gel. A mechanism of formation of the layer of nano-Ca12Al14O33 was proposed and optimized, with calcination temperatures ranging from 900 to 1000 °C and Ca/Al molar ratios between 2.3 and 3.5. The attrition behavior of the adsorbent was investigated in detail using the air jet method to measure fine loss, as well as with scanning electron microscopy and a particle size analyzer to examine the changes in surface morphology and particle size distribution. The attrition studies showed that complete formation of a Ca12Al14O33 nanoscale framework under calcination temperatures ranging from 900 to 1000 °C and Ca/Al molar ratios between 2.3 and 3.5 resulted in improved resistance to attrition and increased durability of the reactive sorption capacity of the adsorbent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901561e [article] Formation of a Ca12Al14O33 nanolayer and its effect on the attrition behavior of CO2 - adsorbent microspheres composed of CaO nanoparticles [texte imprimé] / Su F. Wu, Auteur ; Ming Z. Jiang, Auteur . - 2011 . - pp. 12269–12275. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12269–12275 Mots-clés : Nanolayer Microspheres Nanoparticles Résumé : The attrition behavior of microspheres composed of CaO nanoparticles that were used as high-temperature CO2-reactive adsorbents was investigated. The nano-CaO/Al2O3 microsphere adsorbents were prepared by a spray technique from a slurry containing a precursor of CaCO3 nanoparticles and an aluminum oxide gel. A mechanism of formation of the layer of nano-Ca12Al14O33 was proposed and optimized, with calcination temperatures ranging from 900 to 1000 °C and Ca/Al molar ratios between 2.3 and 3.5. The attrition behavior of the adsorbent was investigated in detail using the air jet method to measure fine loss, as well as with scanning electron microscopy and a particle size analyzer to examine the changes in surface morphology and particle size distribution. The attrition studies showed that complete formation of a Ca12Al14O33 nanoscale framework under calcination temperatures ranging from 900 to 1000 °C and Ca/Al molar ratios between 2.3 and 3.5 resulted in improved resistance to attrition and increased durability of the reactive sorption capacity of the adsorbent. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901561e

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Modeling of vapor - liquid equilibria for CO2 + 1 - alkanol binary systems with the PC - SAFT equation of state using polar contributions / Luis A. Roman-Ramirez in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12276-12283 Titre : Modeling of vapor - liquid equilibria for CO2 + 1 - alkanol binary systems with the PC - SAFT equation of state using polar contributions Type de document : texte imprimé Auteurs : Luis A. Roman-Ramirez, Auteur ; Fernando Garcia-Sanchez, Auteur ; Ciro H. Ortiz-Estrada, Auteur Année de publication : 2011 Article en page(s) : pp. 12276-12283 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic properties Equations of state Binary system Carbon dioxide Phase equilibrium Liquid vapor Modeling Résumé : In this work, we present the modeling of the vapor—liquid equilibria for the binary systems CO2 + 1-alkanol (from methanol to 1-nonanol) using the PC-SAFT equation of state as the thermodynamic model for the liquid and vapor phases. Four different versions of the PC-SAFT model were compared: the quadrupolar version for the CO2 moleculc, the dipolar version for alkanols, a dipolar + quadrupolar version for CO2 and alkanols without considering cross-interactions, and the original version of the PC-SAFT equation. For the modeling of these systems, binary interaction parameters were fitted to experimental binary vapor-liquid equilibrium data of the form kij = k0ij + k1ij/T. The results obtained showed that, for pure compounds, the inclusion of the dipolar term improved the predictions of the saturation region slightly, whereas for binary systems, the PC-SAFT model with dipolar and quadrupolar contributions yielded the best predictions of the experimental behavior, mainly because of the quadrupolar contribution for the CO2 molecule. The dipolar version of the PC-SAFT equation gave no better predictions than those obtained with the original PC-SAFT model with an association contribution. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463392 [article] Modeling of vapor - liquid equilibria for CO2 + 1 - alkanol binary systems with the PC - SAFT equation of state using polar contributions [texte imprimé] / Luis A. Roman-Ramirez, Auteur ; Fernando Garcia-Sanchez, Auteur ; Ciro H. Ortiz-Estrada, Auteur . - 2011 . - pp. 12276-12283. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12276-12283 Mots-clés : Thermodynamic properties Equations of state Binary system Carbon dioxide Phase equilibrium Liquid vapor Modeling Résumé : In this work, we present the modeling of the vapor—liquid equilibria for the binary systems CO2 + 1-alkanol (from methanol to 1-nonanol) using the PC-SAFT equation of state as the thermodynamic model for the liquid and vapor phases. Four different versions of the PC-SAFT model were compared: the quadrupolar version for the CO2 moleculc, the dipolar version for alkanols, a dipolar + quadrupolar version for CO2 and alkanols without considering cross-interactions, and the original version of the PC-SAFT equation. For the modeling of these systems, binary interaction parameters were fitted to experimental binary vapor-liquid equilibrium data of the form kij = k0ij + k1ij/T. The results obtained showed that, for pure compounds, the inclusion of the dipolar term improved the predictions of the saturation region slightly, whereas for binary systems, the PC-SAFT model with dipolar and quadrupolar contributions yielded the best predictions of the experimental behavior, mainly because of the quadrupolar contribution for the CO2 molecule. The dipolar version of the PC-SAFT equation gave no better predictions than those obtained with the original PC-SAFT model with an association contribution. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463392

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Using screening test results to predict the effective viscosity of swollen superabsorbent polymer particles extrusion through an open fracture / Zhang, Hao in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12284–12293 Titre : Using screening test results to predict the effective viscosity of swollen superabsorbent polymer particles extrusion through an open fracture Type de document : texte imprimé Auteurs : Zhang, Hao, Auteur ; Rajesh S. Challa, Auteur ; Baojun Bai, Auteur Année de publication : 2011 Article en page(s) : pp. 12284–12293 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Viscosity Polymer Résumé : Superabsorbent polymer particles, also called preformed particle gels (PPGs), have been successfully applied to reduce water production and enhance oil production in mature reservoirs with fractures or super-high-permeability streaks/channels. The applied particles usually range in size from a few hundred micrometers to a few millimeters and are irregular in shape, which make it impossible to measure their rheology behavior using a traditional rheometer. A simple method, a screen model test, was designed to evaluate the rheological behavior of the swollen PPG. The results show that a swollen PPG is a shear-thinning material with properties that can be expressed using a power-law equation from which an apparent consistency constant and an apparent flow index can be obtained. Considering the shear-thinning properties, we first developed a theoretical mathematical model using a general power-law equation to predict the pressure gradient of a swollen PPG during its extrusion through a fracture. Then, we modified the model by correlating screen test results with fracture experiment results so that the apparent consistency constant and the apparent flow index obtained from the screen tests were introduced to replace the consistency constant and flow index from the general power-law equation. These equations correlated effective viscosity with flow rate, fracture width, apparent consistency constant, and apparent flow index together. The newly developed correlations were validated, and the results showed that a single group of screen test measurements can be applied to determine the effective viscosity of a PPG in a fracture with limited errors. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100917m [article] Using screening test results to predict the effective viscosity of swollen superabsorbent polymer particles extrusion through an open fracture [texte imprimé] / Zhang, Hao, Auteur ; Rajesh S. Challa, Auteur ; Baojun Bai, Auteur . - 2011 . - pp. 12284–12293. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12284–12293 Mots-clés : Viscosity Polymer Résumé : Superabsorbent polymer particles, also called preformed particle gels (PPGs), have been successfully applied to reduce water production and enhance oil production in mature reservoirs with fractures or super-high-permeability streaks/channels. The applied particles usually range in size from a few hundred micrometers to a few millimeters and are irregular in shape, which make it impossible to measure their rheology behavior using a traditional rheometer. A simple method, a screen model test, was designed to evaluate the rheological behavior of the swollen PPG. The results show that a swollen PPG is a shear-thinning material with properties that can be expressed using a power-law equation from which an apparent consistency constant and an apparent flow index can be obtained. Considering the shear-thinning properties, we first developed a theoretical mathematical model using a general power-law equation to predict the pressure gradient of a swollen PPG during its extrusion through a fracture. Then, we modified the model by correlating screen test results with fracture experiment results so that the apparent consistency constant and the apparent flow index obtained from the screen tests were introduced to replace the consistency constant and flow index from the general power-law equation. These equations correlated effective viscosity with flow rate, fracture width, apparent consistency constant, and apparent flow index together. The newly developed correlations were validated, and the results showed that a single group of screen test measurements can be applied to determine the effective viscosity of a PPG in a fracture with limited errors. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100917m

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Thermodynamic properties of pentaerythritol - based species involved in degradation of aviation gas turbine lubricants / Spiridon Siouris in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12294–12301 Titre : Thermodynamic properties of pentaerythritol - based species involved in degradation of aviation gas turbine lubricants Type de document : texte imprimé Auteurs : Spiridon Siouris, Auteur ; Christopher W. Wilson, Auteur Année de publication : 2011 Article en page(s) : pp. 12294–12301 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Thermodynamic Gas Turbine Lubricants Résumé : The work in this Article deals with the estimation of thermodynamic data for the major species found during lubricant degradation. The organic group R on which the species were based was the pentaerythritol molecule. A computer code was developed that utilizes zero-order and bond additivity methods for the estimation of thermodynamic properties. The validation of the code was carried out against thermodynamic data for species found in published databases and showed that the computed values for heat capacity, enthalpy, and entropy were in close agreement with the reference values. Having gained confidence in the reliability of the developed code, the thermodynamic properties of species involved in aviation gas turbine lubricants were estimated and are presented in this Article. This work is the first part toward a study for the development of a lubricant degradation model in which the changes in the thermodynamic properties, and therefore heat transfer, due to chemical reactions are accounted for. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101236n [article] Thermodynamic properties of pentaerythritol - based species involved in degradation of aviation gas turbine lubricants [texte imprimé] / Spiridon Siouris, Auteur ; Christopher W. Wilson, Auteur . - 2011 . - pp. 12294–12301. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12294–12301 Mots-clés : Thermodynamic Gas Turbine Lubricants Résumé : The work in this Article deals with the estimation of thermodynamic data for the major species found during lubricant degradation. The organic group R on which the species were based was the pentaerythritol molecule. A computer code was developed that utilizes zero-order and bond additivity methods for the estimation of thermodynamic properties. The validation of the code was carried out against thermodynamic data for species found in published databases and showed that the computed values for heat capacity, enthalpy, and entropy were in close agreement with the reference values. Having gained confidence in the reliability of the developed code, the thermodynamic properties of species involved in aviation gas turbine lubricants were estimated and are presented in this Article. This work is the first part toward a study for the development of a lubricant degradation model in which the changes in the thermodynamic properties, and therefore heat transfer, due to chemical reactions are accounted for. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101236n

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Molten slag flow and phase transformation behaviors in a slagging entrained - flow coal gasifier / Jianjun Ni in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12302–12310 Titre : Molten slag flow and phase transformation behaviors in a slagging entrained - flow coal gasifier Type de document : texte imprimé Auteurs : Jianjun Ni, Auteur ; Zhijie Zhou, Auteur ; Guangsuo Yu, Auteur Année de publication : 2011 Article en page(s) : pp. 12302–12310 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Coal Phase transformation Slag Résumé : A slag flow submodel has been developed to simulate the slag flow and phase transformation behaviors in coal gasifiers. The volume of the fluid (VOF) model is used to capture the free surface of the slag flow, and the continuum surface force (CSF) model is employed to calculate the surface tension between the gas phase and the liquid slag phase. The slag is treated as a Newtonian fluid when the slag temperature is above the critical viscosity temperature (Tcv), and plastic fluid is treated when the slag temperature is between the flow temperature (Tf) and the Tcv. The ash particle deposition, viscosity−temperature dependence, and different thermal conductivity for different slag phase are all included in the present simulation. For membrane wall coal gasification, the liquid slag and solid slag layer increases along the flow and total slag thickness increases as the operating temperature decreases. The velocity profiles and viscosity profiles at different operating temperatures are performed. The liquid slag flow will produce fluctuations when the slag temperature decreases to the lowest at the bottom of the gasifier. In addition, the temperature difference (To − Tf) between 150 and 200 °C is suitable for a membrane wall coal entrained-flow gasifier. For refractory wall coal gasification, the thicker refractory bricks can effectively prevent the heat lost from the gasifier wall, so the slag flow is steady when the operating temperature is higher than the critical operating temperature. An expression of solid slag layer formation criterion has been deduced from heat-transfer balance. The critical operating temperature of the different slag mass flow rate is studied by heat-transfer balance. In addition, the solid slag layer will rapidly increase as the operating temperature decreases to critical operating temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463395 [article] Molten slag flow and phase transformation behaviors in a slagging entrained - flow coal gasifier [texte imprimé] / Jianjun Ni, Auteur ; Zhijie Zhou, Auteur ; Guangsuo Yu, Auteur . - 2011 . - pp. 12302–12310. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12302–12310 Mots-clés : Coal Phase transformation Slag Résumé : A slag flow submodel has been developed to simulate the slag flow and phase transformation behaviors in coal gasifiers. The volume of the fluid (VOF) model is used to capture the free surface of the slag flow, and the continuum surface force (CSF) model is employed to calculate the surface tension between the gas phase and the liquid slag phase. The slag is treated as a Newtonian fluid when the slag temperature is above the critical viscosity temperature (Tcv), and plastic fluid is treated when the slag temperature is between the flow temperature (Tf) and the Tcv. The ash particle deposition, viscosity−temperature dependence, and different thermal conductivity for different slag phase are all included in the present simulation. For membrane wall coal gasification, the liquid slag and solid slag layer increases along the flow and total slag thickness increases as the operating temperature decreases. The velocity profiles and viscosity profiles at different operating temperatures are performed. The liquid slag flow will produce fluctuations when the slag temperature decreases to the lowest at the bottom of the gasifier. In addition, the temperature difference (To − Tf) between 150 and 200 °C is suitable for a membrane wall coal entrained-flow gasifier. For refractory wall coal gasification, the thicker refractory bricks can effectively prevent the heat lost from the gasifier wall, so the slag flow is steady when the operating temperature is higher than the critical operating temperature. An expression of solid slag layer formation criterion has been deduced from heat-transfer balance. The critical operating temperature of the different slag mass flow rate is studied by heat-transfer balance. In addition, the solid slag layer will rapidly increase as the operating temperature decreases to critical operating temperature. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463395

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Comparative study of solid - phase extraction and liquid − liquid extraction for the reliable quantification of high value added compounds from oxidation processes of wood - derived lignin / Paula C. Rodrigues Pinto in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12311–12318 Titre : Comparative study of solid - phase extraction and liquid − liquid extraction for the reliable quantification of high value added compounds from oxidation processes of wood - derived lignin Type de document : texte imprimé Auteurs : Paula C. Rodrigues Pinto, Auteur ; Eduardo A. Borges da Silva, Auteur ; Alirio Egidio Rodrigues, Auteur Année de publication : 2011 Article en page(s) : pp. 12311–12318 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solid phase Liquid Oxidation processes Résumé : Technologies and processes for lignocellulosic conversion in biorefineries are emergent subjects of research for which a reliable analysis of raw materials and quantification of yields of reaction products are required. This paper presents the development of an analytical method, using solid-phase extraction (SPE), for application to the reaction mixture of the oxidation of wood-derived lignin. The aim of the method is to extract the high value added aldehydes for quantification by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). SPE and conventional liquid−liquid extraction (LLE) were evaluated and compared concerning recoveries and precision: (i) solutions of standard phenolic compounds (in alkaline medium and in lignin as matrix) and (ii) real samples and spiked real samples. The presence of lignin in the solutions decreases the recoveries of compounds from about 100% (no lignin) to 91% (for prepared solutions of lignin) and 94% (for real samples). This decrease was clearly evident with the increase of concentration of phenolic compounds in spiked real samples. The recovery averages and precision of SPE were higher than those of LLE and less affected by the presence of lignin. The results gathered and discussed in this work revealed SPE as an alternative to LLE: it is less time-consuming and has higher accuracy and precision for the quantification of phenolic compounds as reaction products of lignin oxidation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101680s [article] Comparative study of solid - phase extraction and liquid − liquid extraction for the reliable quantification of high value added compounds from oxidation processes of wood - derived lignin [texte imprimé] / Paula C. Rodrigues Pinto, Auteur ; Eduardo A. Borges da Silva, Auteur ; Alirio Egidio Rodrigues, Auteur . - 2011 . - pp. 12311–12318. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12311–12318 Mots-clés : Solid phase Liquid Oxidation processes Résumé : Technologies and processes for lignocellulosic conversion in biorefineries are emergent subjects of research for which a reliable analysis of raw materials and quantification of yields of reaction products are required. This paper presents the development of an analytical method, using solid-phase extraction (SPE), for application to the reaction mixture of the oxidation of wood-derived lignin. The aim of the method is to extract the high value added aldehydes for quantification by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). SPE and conventional liquid−liquid extraction (LLE) were evaluated and compared concerning recoveries and precision: (i) solutions of standard phenolic compounds (in alkaline medium and in lignin as matrix) and (ii) real samples and spiked real samples. The presence of lignin in the solutions decreases the recoveries of compounds from about 100% (no lignin) to 91% (for prepared solutions of lignin) and 94% (for real samples). This decrease was clearly evident with the increase of concentration of phenolic compounds in spiked real samples. The recovery averages and precision of SPE were higher than those of LLE and less affected by the presence of lignin. The results gathered and discussed in this work revealed SPE as an alternative to LLE: it is less time-consuming and has higher accuracy and precision for the quantification of phenolic compounds as reaction products of lignin oxidation. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101680s

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High - pressure differential scanning calorimetry measurements of the mass transfer resistance across a methane hydrate film as a function of time and subcooling / Simon R. Davies in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12319–12326 Titre : High - pressure differential scanning calorimetry measurements of the mass transfer resistance across a methane hydrate film as a function of time and subcooling Type de document : texte imprimé Auteurs : Simon R. Davies, Auteur ; Jason W. Lachance, Auteur ; E. Dendy Sloan, Auteur Année de publication : 2011 Article en page(s) : pp. 12319–12326 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mass transfer Methane Résumé : High pressure differential scanning calorimetry was utilized to study the mass transfer rates across methane hydrate films grown at hydrocarbon−water interfaces in a quiescent system, as a function of subcooling and the age of the film. Gas hydrate films formed at such interfaces provide a substantial barrier to further gas hydrate formation. The initially high mass transfer rates across the gas hydrate films formed at gas−water interfaces confirmed that the films were porous in nature containing varying degrees of porosity, with the films requiring up to >24 h to anneal. Conversely, films formed at water−liquid hydrocarbon interfaces exhibited much lower mass transfer rates. The mass transfer rate is also dependent on the formation conditions of the film and is at a maximum at around 22 K of subcooling. This maximum appears to be independent of gas hydrate structure and pressure. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017173 [article] High - pressure differential scanning calorimetry measurements of the mass transfer resistance across a methane hydrate film as a function of time and subcooling [texte imprimé] / Simon R. Davies, Auteur ; Jason W. Lachance, Auteur ; E. Dendy Sloan, Auteur . - 2011 . - pp. 12319–12326. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12319–12326 Mots-clés : Mass transfer Methane Résumé : High pressure differential scanning calorimetry was utilized to study the mass transfer rates across methane hydrate films grown at hydrocarbon−water interfaces in a quiescent system, as a function of subcooling and the age of the film. Gas hydrate films formed at such interfaces provide a substantial barrier to further gas hydrate formation. The initially high mass transfer rates across the gas hydrate films formed at gas−water interfaces confirmed that the films were porous in nature containing varying degrees of porosity, with the films requiring up to >24 h to anneal. Conversely, films formed at water−liquid hydrocarbon interfaces exhibited much lower mass transfer rates. The mass transfer rate is also dependent on the formation conditions of the film and is at a maximum at around 22 K of subcooling. This maximum appears to be independent of gas hydrate structure and pressure. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1017173

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Kinetic analysis of chalcone epoxidation in a biphasic system / Wai Wing Leung in Industrial & engineering chemistry research, Vol. 49 N° 23 (Décembre 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12327–12330 Titre : Kinetic analysis of chalcone epoxidation in a biphasic system Type de document : texte imprimé Auteurs : Wai Wing Leung, Auteur ; Ruben M. Savizky, Auteur Année de publication : 2011 Article en page(s) : pp. 12327–12330 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Biphasic system Epoxidation Kinetics Résumé : The kinetics of chalcone epoxidation in a biphasic water/heptane medium system consisting of chalcone as the substrate, hydrogen peroxide as the oxidant, sodium hydroxide as the base, and dodecyltrimethylammonium bromide (DTAB) as the surfactant was investigated. The empirical rate law was established to be described as follows: rate = k[chalcone]0.74[DTAB]0.50[NaOH]0.87[H2O2]1.53. As a preliminary study, the apparent activation energy of the reaction was determined to be 25.9 kJ/mol. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463398 [article] Kinetic analysis of chalcone epoxidation in a biphasic system [texte imprimé] / Wai Wing Leung, Auteur ; Ruben M. Savizky, Auteur . - 2011 . - pp. 12327–12330. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 23 (Décembre 2010) . - pp. 12327–12330 Mots-clés : Biphasic system Epoxidation Kinetics Résumé : The kinetics of chalcone epoxidation in a biphasic water/heptane medium system consisting of chalcone as the substrate, hydrogen peroxide as the oxidant, sodium hydroxide as the base, and dodecyltrimethylammonium bromide (DTAB) as the surfactant was investigated. The empirical rate law was established to be described as follows: rate = k[chalcone]0.74[DTAB]0.50[NaOH]0.87[H2O2]1.53. As a preliminary study, the apparent activation energy of the reaction was determined to be 25.9 kJ/mol. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23463398

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