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Kinetics of ethylbenzene ethylation with ethanol over a ZSM-5-based catalyst in a riser simulator / S. M. Waziri 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. 8341–8348 Titre : Kinetics of ethylbenzene ethylation with ethanol over a ZSM-5-based catalyst in a riser simulator Type de document : texte imprimé Auteurs : S. M. Waziri, Auteur ; Al-Khattaf, S., Auteur Année de publication : 2010 Article en page(s) : pp. 8341–8348 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ethylbenzene  Catalytic  ethylation  Fluidized-bed  reactors Résumé : The catalytic ethylation of ethylbenzene with ethanol over ZSM-5 based catalyst has been investigated in a riser simulator that closely mimics the operation of fluidized-bed reactors. Experimental runs were conducted with a constant ethylbenzene to ethanol molar ratio of 1:1 over the temperature range of 300−500 °C and reaction times of 3−15 s. The effect of reaction conditions on the variation of ethylbenzene conversion, distribution of diethylbenzene isomers, and values of benzene/diethylbenzene ratios are reported. The results show that at low temperatures (300−400 °C) alkylation is the predominant reaction while at higher temperatures other competing reactions such as disproportionation and cracking are also important. On the basis of these observations, two mechanisms (one for low temperatures and the other for both low and high temperatures) were proposed to represent the ethylation of ethylbenzene with ethanol. The experimental results were modeled using a quasi-steady state approximation with catalyst deactivation function based on a time on stream (TOS) model. Kinetic parameters for ethylation of ethylbenzene with ethanol, disproportionation of ethylbenzene, and cracking of diethylbenzene were estimated by nonlinear regression analysis. The apparent activation energies were found to increase as follows: Ee < Ed < Ec. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900497d [article] Kinetics of ethylbenzene ethylation with ethanol over a ZSM-5-based catalyst in a riser simulator [texte imprimé] / S. M. Waziri, Auteur ; Al-Khattaf, S., Auteur . - 2010 . - pp. 8341–8348. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8341–8348 Mots-clés : Ethylbenzene  Catalytic  ethylation  Fluidized-bed  reactors Résumé : The catalytic ethylation of ethylbenzene with ethanol over ZSM-5 based catalyst has been investigated in a riser simulator that closely mimics the operation of fluidized-bed reactors. Experimental runs were conducted with a constant ethylbenzene to ethanol molar ratio of 1:1 over the temperature range of 300−500 °C and reaction times of 3−15 s. The effect of reaction conditions on the variation of ethylbenzene conversion, distribution of diethylbenzene isomers, and values of benzene/diethylbenzene ratios are reported. The results show that at low temperatures (300−400 °C) alkylation is the predominant reaction while at higher temperatures other competing reactions such as disproportionation and cracking are also important. On the basis of these observations, two mechanisms (one for low temperatures and the other for both low and high temperatures) were proposed to represent the ethylation of ethylbenzene with ethanol. The experimental results were modeled using a quasi-steady state approximation with catalyst deactivation function based on a time on stream (TOS) model. Kinetic parameters for ethylation of ethylbenzene with ethanol, disproportionation of ethylbenzene, and cracking of diethylbenzene were estimated by nonlinear regression analysis. The apparent activation energies were found to increase as follows: Ee < Ed < Ec. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900497d

Transformation of toluene and 1 , 2 , 4 - trimethylbenzene over ZSM - 5 and mordenite catalysts / S. M. Waziri in Industrial & engineering chemistry research, Vol. 49 N° 14 (Juillet 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 14 (Juillet 2010) . - pp. 6376–6387 Titre : Transformation of toluene and 1 , 2 , 4 - trimethylbenzene over ZSM - 5 and mordenite catalysts : A comprehensive kinetic model with reversibility Type de document : texte imprimé Auteurs : S. M. Waziri, Auteur ; A. M. Aitani, Auteur ; Al-Khattaf, S., Auteur Année de publication : 2010 Article en page(s) : pp. 6376–6387 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalytic  transformations  toluene Résumé : The catalytic transformations of toluene, 1,2,4-trimethylbenzene (TMB), and an equimolar mixture of the two compounds were investigated over H-mordenite and H-ZSM-5 catalysts. A series of experiments were conducted in a riser simulator over a temperature range of 300−400 °C and reaction times of 5−20 s. The influence of reaction conditions on variation of 1,2,4-TMB conversion, toluene conversion, para- to ortho-xylene ratio, xylenes to TMB isomers ratio, 1,3,5-TMB to 1,2,3-TMB ratio, and xylenes to benzene ratio were discussed. The study also includes the development of comprehensive kinetic models for isomerization, disproportionation, and transalkylation reactions of 1,2,4-TMB and toluene. The models account for reversibility of the isomerization reaction based on values of temperature dependent thermodynamic equilibrium constants. Catalysts deactivation was modeled using an activity decay function based on time-on-stream (TOS). The developed models gave a good match with experimental data based on a statistically significant estimate of the kinetic parameters in the models. For the 1,2,4-TMB reaction and transalkylation of 1,2,4-TMB with toluene, the apparent activation energy over H-ZSM-5 was higher than that over H-mordenite (i.e., Eapp,(H-ZSM-5) > Eapp,(H-Mordenite)) while the reverse order was observed for the toluene reaction over the two catalysts. A simple correlation that gives accurate representation of the temperature dependency of thermodynamic equilibrium compositions of TMB isomers was also reported. Note de contenu : Industrial chemistry ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100527x [article] Transformation of toluene and 1 , 2 , 4 - trimethylbenzene over ZSM - 5 and mordenite catalysts : A comprehensive kinetic model with reversibility [texte imprimé] / S. M. Waziri, Auteur ; A. M. Aitani, Auteur ; Al-Khattaf, S., Auteur . - 2010 . - pp. 6376–6387. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 14 (Juillet 2010) . - pp. 6376–6387 Mots-clés : Catalytic  transformations  toluene Résumé : The catalytic transformations of toluene, 1,2,4-trimethylbenzene (TMB), and an equimolar mixture of the two compounds were investigated over H-mordenite and H-ZSM-5 catalysts. A series of experiments were conducted in a riser simulator over a temperature range of 300−400 °C and reaction times of 5−20 s. The influence of reaction conditions on variation of 1,2,4-TMB conversion, toluene conversion, para- to ortho-xylene ratio, xylenes to TMB isomers ratio, 1,3,5-TMB to 1,2,3-TMB ratio, and xylenes to benzene ratio were discussed. The study also includes the development of comprehensive kinetic models for isomerization, disproportionation, and transalkylation reactions of 1,2,4-TMB and toluene. The models account for reversibility of the isomerization reaction based on values of temperature dependent thermodynamic equilibrium constants. Catalysts deactivation was modeled using an activity decay function based on time-on-stream (TOS). The developed models gave a good match with experimental data based on a statistically significant estimate of the kinetic parameters in the models. For the 1,2,4-TMB reaction and transalkylation of 1,2,4-TMB with toluene, the apparent activation energy over H-ZSM-5 was higher than that over H-mordenite (i.e., Eapp,(H-ZSM-5) > Eapp,(H-Mordenite)) while the reverse order was observed for the toluene reaction over the two catalysts. A simple correlation that gives accurate representation of the temperature dependency of thermodynamic equilibrium compositions of TMB isomers was also reported. Note de contenu : Industrial chemistry ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100527x