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Application of COSMO-RS type models to the prediction of excess enthalpies / Dana Constantinescu in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8710–8725 Titre : Application of COSMO-RS type models to the prediction of excess enthalpies Type de document : texte imprimé Auteurs : Dana Constantinescu, Auteur ; Jürgen Rarey, Auteur ; Jürgen Gmehling, Auteur Année de publication : 2010 Article en page(s) : pp. 8710–8725 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : COSMO-SAC  models  COSMO-RS(Ol)  models  Excess  enthalpies  Binary  systems Résumé : This article presents a comparative study about the predictive capability of COSMO-SAC and COSMO-RS(Ol) models with respect to excess enthalpies of various binary systems. Results of the group contribution methods UNIFAC and modified UNIFAC (Do) are given for comparison. COSMO calculations were performed using σ profiles based on density functional theory (BP and B3LYP). These were generated by the quantum chemical programs Turbomole and Gaussian 03, with the basis sets used for the calculation being triple-ζ valence polarization (TZVP) for BP and 6-311G(d,p) in the case of B3LYP. All results are compared with experimental data stored in the Dortmund Data Bank for 10 851 binary data sets (5368 different binary mixtures) with over 165 000 experimental data points from nearly 2000 references and are analyzed according to the types of components in the mixture. As expected, the intensively trained mod. UNIFAC (Do) model performs best in predicting the excess enthalpy of binary systems in most cases, but also COSMO-RS type models often lead to astonishingly good results considering the very small number of parameters used. Overall, relative deviations for a common data set of 30.7% (mod. UNIFAC (Do)) and between 56.7% and 80.8% for the different COSMO-RS flavors were obtained. Whenever experimental data indicated a significant change of the excess enthalpy with temperature, the different COSMO-RS type models failed to reproduce this behavior. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900315p [article] Application of COSMO-RS type models to the prediction of excess enthalpies [texte imprimé] / Dana Constantinescu, Auteur ; Jürgen Rarey, Auteur ; Jürgen Gmehling, Auteur . - 2010 . - pp. 8710–8725. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8710–8725 Mots-clés : COSMO-SAC  models  COSMO-RS(Ol)  models  Excess  enthalpies  Binary  systems Résumé : This article presents a comparative study about the predictive capability of COSMO-SAC and COSMO-RS(Ol) models with respect to excess enthalpies of various binary systems. Results of the group contribution methods UNIFAC and modified UNIFAC (Do) are given for comparison. COSMO calculations were performed using σ profiles based on density functional theory (BP and B3LYP). These were generated by the quantum chemical programs Turbomole and Gaussian 03, with the basis sets used for the calculation being triple-ζ valence polarization (TZVP) for BP and 6-311G(d,p) in the case of B3LYP. All results are compared with experimental data stored in the Dortmund Data Bank for 10 851 binary data sets (5368 different binary mixtures) with over 165 000 experimental data points from nearly 2000 references and are analyzed according to the types of components in the mixture. As expected, the intensively trained mod. UNIFAC (Do) model performs best in predicting the excess enthalpy of binary systems in most cases, but also COSMO-RS type models often lead to astonishingly good results considering the very small number of parameters used. Overall, relative deviations for a common data set of 30.7% (mod. UNIFAC (Do)) and between 56.7% and 80.8% for the different COSMO-RS flavors were obtained. Whenever experimental data indicated a significant change of the excess enthalpy with temperature, the different COSMO-RS type models failed to reproduce this behavior. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900315p

Chemical equilibrium conversion of the tert - amyl - methyl - ether synthesis in the presence of n - pentane, tetrahydrofuran, or benzene / Vincent Liebert in Industrial & engineering chemistry research, Vol. 49 N° 9 (Mai 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4412-4419 Titre : Chemical equilibrium conversion of the tert - amyl - methyl - ether synthesis in the presence of n - pentane, tetrahydrofuran, or benzene Type de document : texte imprimé Auteurs : Vincent Liebert, Auteur ; Torben Hector, Auteur ; Jürgen Gmehling, Auteur Année de publication : 2010 Article en page(s) : pp. 4412-4419 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Chemical  equilibrium Résumé : The chemical equilibrium conversion of the reversible liquid-phase etherification of isoamylene with methanol to tert-amyl-methyl-ether using Amberlyst 36 as catalyst was investigated in a temperature range from 312.15 to 354.15 K. The experiments were also carried out in the presence of n-pentane, tetrahydrofuran, or benzene to investigate the influence of different inert solvents on the equilibrium conversion. From the results the standard enthalpy and standard Gibbs energy of reaction have been determined. The experimental conversions have been compared with the predicted conversions assuming ideal and nonideal behavior. For the predictions, tabulated standard thermodynamic properties at 298.15 in the ideal gas state (ΔHf0, ΔGf0), vapor pressures Pis, and standard molar heat capacities cp0 in the liquid phase have been used. The required activity coefficients were calculated with the help of the Wilson model or predicted using the group-contribution method modified UNIFAC (Dortmund). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732929 [article] Chemical equilibrium conversion of the tert - amyl - methyl - ether synthesis in the presence of n - pentane, tetrahydrofuran, or benzene [texte imprimé] / Vincent Liebert, Auteur ; Torben Hector, Auteur ; Jürgen Gmehling, Auteur . - 2010 . - pp. 4412-4419. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 9 (Mai 2010) . - pp. 4412-4419 Mots-clés : Chemical  equilibrium Résumé : The chemical equilibrium conversion of the reversible liquid-phase etherification of isoamylene with methanol to tert-amyl-methyl-ether using Amberlyst 36 as catalyst was investigated in a temperature range from 312.15 to 354.15 K. The experiments were also carried out in the presence of n-pentane, tetrahydrofuran, or benzene to investigate the influence of different inert solvents on the equilibrium conversion. From the results the standard enthalpy and standard Gibbs energy of reaction have been determined. The experimental conversions have been compared with the predicted conversions assuming ideal and nonideal behavior. For the predictions, tabulated standard thermodynamic properties at 298.15 in the ideal gas state (ΔHf0, ΔGf0), vapor pressures Pis, and standard molar heat capacities cp0 in the liquid phase have been used. The required activity coefficients were calculated with the help of the Wilson model or predicted using the group-contribution method modified UNIFAC (Dortmund). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=22732929

Comparison of the a priori COSMO - RS models and group contribution methods / Zhimin Xue in Industrial & engineering chemistry research, Vol. 51 N° 36 (Septembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11809-11817 Titre : Comparison of the a priori COSMO - RS models and group contribution methods : Original UNIFAC, modified UNIFAC(Do), and modified UNIFAC(Do) Co/nsortium Type de document : texte imprimé Auteurs : Zhimin Xue, Auteur ; Tiancheng Mu, Auteur ; Jürgen Gmehling, Auteur Année de publication : 2012 Article en page(s) : pp. 11809-11817 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Group  contribution  method  Modeling Résumé : A comparison of the performances of the COSMO-SAC, COSMO-RS(Ol), original UNIFAC, modified UNIFAC(Do), and modified UNIFAC(Do) Consortium for activity coefficients at infinite dilution and binary VLE data is presented. The σ-profiles used in performing COSMO-SAC and COSMO-RS(Ol) calculations were taken from the published σ-profile database VT 2005. The predicted results were compared with the experimental data stored in the Dortmund Data Bank and analyzed with respect to the types of components in the mixture. The results show that the UNIFAC models based on experimental data are superior to the a priori COSMO-RS models. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350348 [article] Comparison of the a priori COSMO - RS models and group contribution methods : Original UNIFAC, modified UNIFAC(Do), and modified UNIFAC(Do) Co/nsortium [texte imprimé] / Zhimin Xue, Auteur ; Tiancheng Mu, Auteur ; Jürgen Gmehling, Auteur . - 2012 . - pp. 11809-11817. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 36 (Septembre 2012) . - pp. 11809-11817 Mots-clés : Group  contribution  method  Modeling Résumé : A comparison of the performances of the COSMO-SAC, COSMO-RS(Ol), original UNIFAC, modified UNIFAC(Do), and modified UNIFAC(Do) Consortium for activity coefficients at infinite dilution and binary VLE data is presented. The σ-profiles used in performing COSMO-SAC and COSMO-RS(Ol) calculations were taken from the published σ-profile database VT 2005. The predicted results were compared with the experimental data stored in the Dortmund Data Bank and analyzed with respect to the types of components in the mixture. The results show that the UNIFAC models based on experimental data are superior to the a priori COSMO-RS models. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26350348

Thermodynamics of phase equilibria in aqueous strong electrolyte systems / Mi-Yi Li in Industrial & engineering chemistry research, Vol. 50 N° 6 (Mars 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3621-3631 Titre : Thermodynamics of phase equilibria in aqueous strong electrolyte systems Type de document : texte imprimé Auteurs : Mi-Yi Li, Auteur ; Li-Sheng Wang, Auteur ; Jürgen Gmehling, Auteur Année de publication : 2011 Article en page(s) : pp. 3621-3631 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Strong  electrolyte  Phase  equilibrium Résumé : The middle range (MR) parameters of the LIQUAC model were improved as a function of temperature to allow the calculation of the activities of all the species in the solution over a wide temperature and concentration range. New parameters were recorrelated by using the experimental data of osmotic coefficients, vapor-liquid equilibria (VLE), mean ion activity coefficients and salt solubilities from the Dortmund Data Bank (DDB). The coordinates of the eutectics, the peritectics, and the ice-water equilibria of the aqueous electrolyte systems were represented with the model. Standard Gibbs energies of formation, standard enthalpies of formation, and heat capacities of various solids were retrieved from the fitting of their solubility products with respect to temperature or estimated using the group contribution method. The schematic phase diagrams for the salts in aqueous systems are presented in this work. A good agreement of calculated results with the published measurements is observed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944530 [article] Thermodynamics of phase equilibria in aqueous strong electrolyte systems [texte imprimé] / Mi-Yi Li, Auteur ; Li-Sheng Wang, Auteur ; Jürgen Gmehling, Auteur . - 2011 . - pp. 3621-3631. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3621-3631 Mots-clés : Strong  electrolyte  Phase  equilibrium Résumé : The middle range (MR) parameters of the LIQUAC model were improved as a function of temperature to allow the calculation of the activities of all the species in the solution over a wide temperature and concentration range. New parameters were recorrelated by using the experimental data of osmotic coefficients, vapor-liquid equilibria (VLE), mean ion activity coefficients and salt solubilities from the Dortmund Data Bank (DDB). The coordinates of the eutectics, the peritectics, and the ice-water equilibria of the aqueous electrolyte systems were represented with the model. Standard Gibbs energies of formation, standard enthalpies of formation, and heat capacities of various solids were retrieved from the fitting of their solubility products with respect to temperature or estimated using the group contribution method. The schematic phase diagrams for the salts in aqueous systems are presented in this work. A good agreement of calculated results with the published measurements is observed. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944530