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Mechanistic modeling of hydrolysis and esterification for biofuel processes / Shujauddin Changi in Industrial & engineering chemistry research, Vol. 50 N° 22 (Novembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12471-12478 Titre : Mechanistic modeling of hydrolysis and esterification for biofuel processes Type de document : texte imprimé Auteurs : Shujauddin Changi, Auteur ; Tanawan Pinnarat, Auteur ; Phillip E. Savage, Auteur Année de publication : 2012 Article en page(s) : pp. 12471-12478 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Esterification  Hydrolysis  Modeling Résumé : We have elucidated the mechanism for ethyl oleate hydrolysis in high temperature water and its reverse reaction, oleic acid esterification in near- and supercritical ethanol in the absence of any other added compounds. Both reactions are acid catalyzed. H+ (from dissociation of water and oleic acid) and oleic acid serve as catalysts for hydrolysis and H+ alone is the catalyst for esterification. The rate equation arising from the proposed mechanism provided a good fit of experimental conversion data for both hydrolysis and esterification. The rate equation accurately predicted the influence of pH on hydrolysis for acidic and near-neutral conditions. The mechanistic model exhibits the ability to make quantitatively accurate predictions within and outside the original parameter space, especially for a multicomponent system. Sensitivity analysis shows that the values of the dissociation constant of oleic acid in ethanol, water, and ethanol-water systems strongly influence the predicted conversions. There is a need for experimental measurement of pKa for fatty acids in both water and alcohols at elevated temperatures. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745720 [article] Mechanistic modeling of hydrolysis and esterification for biofuel processes [texte imprimé] / Shujauddin Changi, Auteur ; Tanawan Pinnarat, Auteur ; Phillip E. Savage, Auteur . - 2012 . - pp. 12471-12478. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 22 (Novembre 2011) . - pp. 12471-12478 Mots-clés : Esterification  Hydrolysis  Modeling Résumé : We have elucidated the mechanism for ethyl oleate hydrolysis in high temperature water and its reverse reaction, oleic acid esterification in near- and supercritical ethanol in the absence of any other added compounds. Both reactions are acid catalyzed. H+ (from dissociation of water and oleic acid) and oleic acid serve as catalysts for hydrolysis and H+ alone is the catalyst for esterification. The rate equation arising from the proposed mechanism provided a good fit of experimental conversion data for both hydrolysis and esterification. The rate equation accurately predicted the influence of pH on hydrolysis for acidic and near-neutral conditions. The mechanistic model exhibits the ability to make quantitatively accurate predictions within and outside the original parameter space, especially for a multicomponent system. Sensitivity analysis shows that the values of the dissociation constant of oleic acid in ethanol, water, and ethanol-water systems strongly influence the predicted conversions. There is a need for experimental measurement of pKa for fatty acids in both water and alcohols at elevated temperatures. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24745720

Modeling hydrolysis and esterification kinetics for biofuel processes / Shujauddin Changi 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. 3206–3211 Titre : Modeling hydrolysis and esterification kinetics for biofuel processes Type de document : texte imprimé Auteurs : Shujauddin Changi, Auteur ; Tanawan Pinnarat, Auteur Année de publication : 2011 Article en page(s) : pp. 3206–3211 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics Résumé : We determined the kinetics for ethyl oleate hydrolysis in high-temperature water and for the reverse reaction, oleic acid esterification, in near- and supercritical ethanol. Hydrolysis was clearly autocatalytic. The experimental data, from reactions at 150−300 °C, times from 5 to 1440 min, and with different initial concentrations of reactants and products, were used to estimate thermodynamically and thermochemically consistent Arrhenius parameters for the forward and reverse reactions in an autocatalytic reaction model. The model provided a good correlation of the data and also exhibited the ability to make quantitatively accurate predictions within the parameter space investigated. The model also accurately predicted the experimental trends when extrapolated outside the original parameter space. Sensitivity analysis confirmed that data from both fatty acid esterification and fatty acid ester hydrolysis need to be used together if one desires reliable estimates for all of the Arrhenius parameters in the autocatalytic model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1023047 [article] Modeling hydrolysis and esterification kinetics for biofuel processes [texte imprimé] / Shujauddin Changi, Auteur ; Tanawan Pinnarat, Auteur . - 2011 . - pp. 3206–3211. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3206–3211 Mots-clés : Kinetics Résumé : We determined the kinetics for ethyl oleate hydrolysis in high-temperature water and for the reverse reaction, oleic acid esterification, in near- and supercritical ethanol. Hydrolysis was clearly autocatalytic. The experimental data, from reactions at 150−300 °C, times from 5 to 1440 min, and with different initial concentrations of reactants and products, were used to estimate thermodynamically and thermochemically consistent Arrhenius parameters for the forward and reverse reactions in an autocatalytic reaction model. The model provided a good correlation of the data and also exhibited the ability to make quantitatively accurate predictions within the parameter space investigated. The model also accurately predicted the experimental trends when extrapolated outside the original parameter space. Sensitivity analysis confirmed that data from both fatty acid esterification and fatty acid ester hydrolysis need to be used together if one desires reliable estimates for all of the Arrhenius parameters in the autocatalytic model. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1023047