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Density of ionic liquids using group contribution and artificial neural networks / José O. Valderrama in Industrial & engineering chemistry research, Vol. 48 N° 6 (Mars 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 3254–3259 Titre : Density of ionic liquids using group contribution and artificial neural networks Type de document : texte imprimé Auteurs : José O. Valderrama, Auteur ; Alfonso Reátegui, Auteur ; Roberto E. Rojas, Auteur Année de publication : 2009 Article en page(s) : pp. 3254–3259 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Artificial  neural  networks  Ionic  liquids  Artificial  neural  network Résumé : Artificial neural networks and the concept of group contribution are simultaneously used to correlate and predict the density of ionic liquids. Different topologies of a multilayer feed forward artificial neural network were studied and the optimum architecture was determined. Density data from the literature for 103 ionic liquids with 399 data points have been used for training the network. To discriminate among the different substances, the molecular mass and the structure of the molecule, defined by the concepts of the classical group contribution methods, were given as input variables. The capabilities of the designed network were tested by predicting densities for situations not considered during the training process of the network (82 density data points for 24 ionic liquids). The results demonstrate that the chosen network and the group contribution method employed are able to estimate the density of ionic liquids with acceptable accuracy for engineering calculations. The program codes and the necessary input files to calculate the density for other ionic liquids are provided. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801113x [article] Density of ionic liquids using group contribution and artificial neural networks [texte imprimé] / José O. Valderrama, Auteur ; Alfonso Reátegui, Auteur ; Roberto E. Rojas, Auteur . - 2009 . - pp. 3254–3259. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 3254–3259 Mots-clés : Artificial  neural  networks  Ionic  liquids  Artificial  neural  network Résumé : Artificial neural networks and the concept of group contribution are simultaneously used to correlate and predict the density of ionic liquids. Different topologies of a multilayer feed forward artificial neural network were studied and the optimum architecture was determined. Density data from the literature for 103 ionic liquids with 399 data points have been used for training the network. To discriminate among the different substances, the molecular mass and the structure of the molecule, defined by the concepts of the classical group contribution methods, were given as input variables. The capabilities of the designed network were tested by predicting densities for situations not considered during the training process of the network (82 density data points for 24 ionic liquids). The results demonstrate that the chosen network and the group contribution method employed are able to estimate the density of ionic liquids with acceptable accuracy for engineering calculations. The program codes and the necessary input files to calculate the density for other ionic liquids are provided. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801113x

Thermodynamic consistency test of vapor−liquid equilibrium data for mixtures containing ionic liquids / José O. Valderrama in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8416–8422 Titre : Thermodynamic consistency test of vapor−liquid equilibrium data for mixtures containing ionic liquids Type de document : texte imprimé Auteurs : José O. Valderrama, Auteur ; Alfonso Reátegui, Auteur ; Wilson W. Sanga, Auteur Année de publication : 2008 Article en page(s) : p. 8416–8422 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Thermodynamicionic  liquid Résumé : Vapor−liquid equilibrium of eight binary mixtures containing an ionic liquid and carbon dioxide have been tested for thermodynamic consistency. A method proposed by one of the authors has been modified to be applied to this special situation in which the gas phase contains practically one component (carbon dioxide) while the liquid phase contains both components in a wide concentration range. The method is based on the Gibbs−Duhem equation and on appropriate combination of equations of state, mixing rules, and combining rules. The Peng−Robinson equation of state with the Wong−Sandler mixing rules including the Van Laar model for the excess Gibbs free energy required in the mixing rules, are used. The experimental data were obtained from literature sources, and the adjustable parameters were found by minimizing the errors between predicted and experimental bubble pressure. It is shown that the proposed modified consistency test is accurate enough to decide about the thermodynamic consistency of this type of data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800763x [article] Thermodynamic consistency test of vapor−liquid equilibrium data for mixtures containing ionic liquids [texte imprimé] / José O. Valderrama, Auteur ; Alfonso Reátegui, Auteur ; Wilson W. Sanga, Auteur . - 2008 . - p. 8416–8422. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8416–8422 Mots-clés : Thermodynamicionic  liquid Résumé : Vapor−liquid equilibrium of eight binary mixtures containing an ionic liquid and carbon dioxide have been tested for thermodynamic consistency. A method proposed by one of the authors has been modified to be applied to this special situation in which the gas phase contains practically one component (carbon dioxide) while the liquid phase contains both components in a wide concentration range. The method is based on the Gibbs−Duhem equation and on appropriate combination of equations of state, mixing rules, and combining rules. The Peng−Robinson equation of state with the Wong−Sandler mixing rules including the Van Laar model for the excess Gibbs free energy required in the mixing rules, are used. The experimental data were obtained from literature sources, and the adjustable parameters were found by minimizing the errors between predicted and experimental bubble pressure. It is shown that the proposed modified consistency test is accurate enough to decide about the thermodynamic consistency of this type of data. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800763x