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Experimental and theoretical study of chemical equilibria in the reactive systems of acetals synthesis / Viviana M. T. M. Silva in Industrial & engineering chemistry research, Vol. 51 N° 39 (Octobre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12723-12729 Titre : Experimental and theoretical study of chemical equilibria in the reactive systems of acetals synthesis Type de document : texte imprimé Auteurs : Viviana M. T. M. Silva, Auteur ; Carla S. M. Pereira, Auteur ; Alirio E. Rodrigues, Auteur Année de publication : 2012 Article en page(s) : pp. 12723-12729 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Chemical  equilibrium Résumé : The chemical equilibria of acetals of acetaldehyde reactive systems (with methanol, ethanol, and n-butanol to form 1,1-dimethoxyethane, 1,1-diethoxyethane, and 1,1-dibuthoxyethane, respectively) were studied in the temperature range (293-333 K) in the liquid phase. The three reactive systems exhibit a strong nonideal behavior in the liquid phase. The knowledge of the activity coefficients is required to obtain the thermodynamic equilibrium constants Ka. The activity coefficients were estimated by the modified UNIFAC method, which already includes the parameters for the acetal group. The reaction enthalpies for the three acetalizations in the liquid phase were obtained from the temperature dependences of the corresponding thermodynamic equilibrium constants. These values were compared to those obtained by high-level ab initio calculations of the reaction participants using the Gaussian 03 program package. Absolute electronic energy values of the molecules have been obtained using G3(MP2) level. Using these results, calculated equilibrium constants and enthalpies of reaction of the acetals synthesis in the liquid phase based on the principles of statistical thermodynamics are found to be in acceptable agreement with the data obtained from the thermochemical measurements. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419227 [article] Experimental and theoretical study of chemical equilibria in the reactive systems of acetals synthesis [texte imprimé] / Viviana M. T. M. Silva, Auteur ; Carla S. M. Pereira, Auteur ; Alirio E. Rodrigues, Auteur . - 2012 . - pp. 12723-12729. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 39 (Octobre 2012) . - pp. 12723-12729 Mots-clés : Chemical  equilibrium Résumé : The chemical equilibria of acetals of acetaldehyde reactive systems (with methanol, ethanol, and n-butanol to form 1,1-dimethoxyethane, 1,1-diethoxyethane, and 1,1-dibuthoxyethane, respectively) were studied in the temperature range (293-333 K) in the liquid phase. The three reactive systems exhibit a strong nonideal behavior in the liquid phase. The knowledge of the activity coefficients is required to obtain the thermodynamic equilibrium constants Ka. The activity coefficients were estimated by the modified UNIFAC method, which already includes the parameters for the acetal group. The reaction enthalpies for the three acetalizations in the liquid phase were obtained from the temperature dependences of the corresponding thermodynamic equilibrium constants. These values were compared to those obtained by high-level ab initio calculations of the reaction participants using the Gaussian 03 program package. Absolute electronic energy values of the molecules have been obtained using G3(MP2) level. Using these results, calculated equilibrium constants and enthalpies of reaction of the acetals synthesis in the liquid phase based on the principles of statistical thermodynamics are found to be in acceptable agreement with the data obtained from the thermochemical measurements. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26419227

Green fuel production using the permSMBR technology / Carla S. M. Pereira in Industrial & engineering chemistry research, Vol. 51 N° 26 (Juillet 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8928–8938 Titre : Green fuel production using the permSMBR technology Type de document : texte imprimé Auteurs : Carla S. M. Pereira, Auteur ; Viviana M. T. M. Silva, Auteur ; Alirio E. Rodrigues, Auteur Année de publication : 2012 Article en page(s) : pp. 8928–8938 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Green  fuel Résumé : The production of the green fuel acetaldehyde dibutylacetal (1,1-dibutoxyethane, DBE) was implemented by means of a new hybrid technology, the Simulated Moving Bed Membrane Reactor (PermSMBR), which consists in a Simulated Moving Bed Reactor (SMBR) integrated with membranes. The PermSMBR and SMBR processes performances were numerically evaluated and compared. The new hybrid technology proved to be a very efficient process for DBE production, leading to a productivity of 70.77 kgDBE·Lresin-1·day-1 with a desorbent consumption of 0.33 Ln-Butanol/kgDBE, which corresponds to a productivity enhancement of 31% and a desorbent consumption reduction of 88% when compared with the SMBR technology. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201951d [article] Green fuel production using the permSMBR technology [texte imprimé] / Carla S. M. Pereira, Auteur ; Viviana M. T. M. Silva, Auteur ; Alirio E. Rodrigues, Auteur . - 2012 . - pp. 8928–8938. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 26 (Juillet 2012) . - pp. 8928–8938 Mots-clés : Green  fuel Résumé : The production of the green fuel acetaldehyde dibutylacetal (1,1-dibutoxyethane, DBE) was implemented by means of a new hybrid technology, the Simulated Moving Bed Membrane Reactor (PermSMBR), which consists in a Simulated Moving Bed Reactor (SMBR) integrated with membranes. The PermSMBR and SMBR processes performances were numerically evaluated and compared. The new hybrid technology proved to be a very efficient process for DBE production, leading to a productivity of 70.77 kgDBE·Lresin-1·day-1 with a desorbent consumption of 0.33 Ln-Butanol/kgDBE, which corresponds to a productivity enhancement of 31% and a desorbent consumption reduction of 88% when compared with the SMBR technology. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201951d

Multifunctional reactor for the synthesis of dimethylacetal / Carla S. M. Pereira in Industrial & engineering chemistry research, Vol. 47 N°10 (Mai 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°10 (Mai 2008) . - p. 3515–3524 Titre : Multifunctional reactor for the synthesis of dimethylacetal Type de document : texte imprimé Auteurs : Carla S. M. Pereira, Auteur ; Pedro Sa Gomes, Auteur ; Ganesh K. Gandi, Auteur ; Viviana M. T. M. Silva, Auteur Année de publication : 2008 Article en page(s) : p. 3515–3524 Note générale : Bibliogr. p. 3523-3524 Langues : Anglais (eng) Mots-clés : Dimethylacetal;  Simulated  moving  bed  reactor Résumé : The synthesis of dimethylacetal (1,1-dimethoxyethane) was performed in a Simulated Moving Bed Reactor (SMBR) pilot unit LICOSEP 12-26 (Novasep, France) with 12 columns packed with the acid resin Amberlyst-15 wet (Rohm & Haas, France). For the operating conditions used, the performance parameters obtained were as follows:  acetal purity, 91.41%; productivity rate, 5.17 kgacetal/(Ladsorbent day); and desorbent consumption, 7.11 Lmethanol/kgacetal. The effect of the switching time, feed composition, and desorbent flow rate in the performance of the SMBR was studied by means of two mathematical models approaches:  the SMBR model (for the concentration profiles and performance parameters) and the True Moving Bed Reactor (TMBR) model (for the reaction separation regions). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070889t [article] Multifunctional reactor for the synthesis of dimethylacetal [texte imprimé] / Carla S. M. Pereira, Auteur ; Pedro Sa Gomes, Auteur ; Ganesh K. Gandi, Auteur ; Viviana M. T. M. Silva, Auteur . - 2008 . - p. 3515–3524. Bibliogr. p. 3523-3524 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°10 (Mai 2008) . - p. 3515–3524 Mots-clés : Dimethylacetal;  Simulated  moving  bed  reactor Résumé : The synthesis of dimethylacetal (1,1-dimethoxyethane) was performed in a Simulated Moving Bed Reactor (SMBR) pilot unit LICOSEP 12-26 (Novasep, France) with 12 columns packed with the acid resin Amberlyst-15 wet (Rohm & Haas, France). For the operating conditions used, the performance parameters obtained were as follows:  acetal purity, 91.41%; productivity rate, 5.17 kgacetal/(Ladsorbent day); and desorbent consumption, 7.11 Lmethanol/kgacetal. The effect of the switching time, feed composition, and desorbent flow rate in the performance of the SMBR was studied by means of two mathematical models approaches:  the SMBR model (for the concentration profiles and performance parameters) and the True Moving Bed Reactor (TMBR) model (for the reaction separation regions). En ligne : http://pubs.acs.org/doi/abs/10.1021/ie070889t