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Chitin microstructure formation by rapid expansion techniques with supercritical carbon dioxide / Ricardo Salinas-Hernández in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 769–778 Titre : Chitin microstructure formation by rapid expansion techniques with supercritical carbon dioxide Type de document : texte imprimé Auteurs : Ricardo Salinas-Hernández, Auteur ; F. Alberto Ruiz-Trevino, Auteur ; Ciro H. Ortiz-Estrada, Auteur Année de publication : 2009 Article en page(s) : p. 769–778 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : Carbon  Dioxide Résumé : Rapid expansion techniques (of supercritical solution (RESS) and into a liquid solvent (RESOLV)) with supercritical carbon dioxide are used to form chitin microstructures. The effect of the pre-expansion conditions, temperature (40−60 °C), pressure (104−208 bar), chitin concentration (1−6 mg/mL), and nozzle diameter (100−500 μm), on the morphology and the size of the chitin microstructures formed with both RESS and RESOLV are studied. Depending on the experimental conditions, it is found that spherical microparticles, with average diameters of 1.7−5.3 μm, are obtained with RESS, while continuous microfibers, with average diameters of 11.5−19.3 μm, are obtained with RESOLV. For both RESS and RESOLV it was observed that the pre-expansion temperature−pressure conditions studied here have practically no effect on the average diameters of the formed material. On the contrary, it is shown that concentration and nozzle diameter directly influence the morphology and size obtaining that lower concentrations and smaller diameter nozzles lead to the production of smaller diameter microstructures and closed-size distributions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800084x [article] Chitin microstructure formation by rapid expansion techniques with supercritical carbon dioxide [texte imprimé] / Ricardo Salinas-Hernández, Auteur ; F. Alberto Ruiz-Trevino, Auteur ; Ciro H. Ortiz-Estrada, Auteur . - 2009 . - p. 769–778. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 769–778 Mots-clés : Carbon  Dioxide Résumé : Rapid expansion techniques (of supercritical solution (RESS) and into a liquid solvent (RESOLV)) with supercritical carbon dioxide are used to form chitin microstructures. The effect of the pre-expansion conditions, temperature (40−60 °C), pressure (104−208 bar), chitin concentration (1−6 mg/mL), and nozzle diameter (100−500 μm), on the morphology and the size of the chitin microstructures formed with both RESS and RESOLV are studied. Depending on the experimental conditions, it is found that spherical microparticles, with average diameters of 1.7−5.3 μm, are obtained with RESS, while continuous microfibers, with average diameters of 11.5−19.3 μm, are obtained with RESOLV. For both RESS and RESOLV it was observed that the pre-expansion temperature−pressure conditions studied here have practically no effect on the average diameters of the formed material. On the contrary, it is shown that concentration and nozzle diameter directly influence the morphology and size obtaining that lower concentrations and smaller diameter nozzles lead to the production of smaller diameter microstructures and closed-size distributions. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800084x

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]  in Industrial & 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  equilibrium  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  equilibrium  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