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Ethylbenzene transformation over a ZSM-5-based catalyst in a riser simulator / Al-Khattaf, S. 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. 2836–2843 Titre : Ethylbenzene transformation over a ZSM-5-based catalyst in a riser simulator Type de document : texte imprimé Auteurs : Al-Khattaf, S., Auteur ; N. M. Tukur, Auteur ; S. Rabiu, Auteur Année de publication : 2009 Article en page(s) : pp. 2836–2843 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Ethylbenzene  transformation  ZSM-5-type  catalyst  Fluidized-bed  reactor  Cracking Résumé : The transformation of ethylbenzene has been studied over a ZSM-5-type catalyst in a riser simulator that mimics the operation of a fluidized-bed reactor. The study was conducted at 350, 375, 400, 450, and 500 °C for reaction times of 3, 5, 7, 10, 13, and 15 s. The effect of reaction conditions on the ratio of cracking to disproportionation products (C/D), the distribution of diethylbenzene (DEB) isomers (m-DEB and p-DEB), and the ratio of benzene/diethylbenzenes (B/DEB) are reported. The experimental results were modeled using quasi-steady-state approximation. Disproportionation was determined to dominate at low temperatures (350−400 °C), while cracking reaction becomes significant as higher temperatures (>400 °C). Thus, two mechanisms were postulated to represent the disappearance of ethylbenzene during the transformation reaction (one mechanism for low temperature, and another for the complete temperature range considered). Kinetic parameters that were used for the disappearance of ethylbenzene during the transformation reaction, and in its conversion into cracking and disproportionation products, were calculated using the catalyst activity decay function, based on the time-on-stream (TOS). The apparent activation energies were determined to decrease: Ecracking > Edisproportionation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801609x [article] Ethylbenzene transformation over a ZSM-5-based catalyst in a riser simulator [texte imprimé] / Al-Khattaf, S., Auteur ; N. M. Tukur, Auteur ; S. Rabiu, Auteur . - 2009 . - pp. 2836–2843. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 6 (Mars 2009) . - pp. 2836–2843 Mots-clés : Ethylbenzene  transformation  ZSM-5-type  catalyst  Fluidized-bed  reactor  Cracking Résumé : The transformation of ethylbenzene has been studied over a ZSM-5-type catalyst in a riser simulator that mimics the operation of a fluidized-bed reactor. The study was conducted at 350, 375, 400, 450, and 500 °C for reaction times of 3, 5, 7, 10, 13, and 15 s. The effect of reaction conditions on the ratio of cracking to disproportionation products (C/D), the distribution of diethylbenzene (DEB) isomers (m-DEB and p-DEB), and the ratio of benzene/diethylbenzenes (B/DEB) are reported. The experimental results were modeled using quasi-steady-state approximation. Disproportionation was determined to dominate at low temperatures (350−400 °C), while cracking reaction becomes significant as higher temperatures (>400 °C). Thus, two mechanisms were postulated to represent the disappearance of ethylbenzene during the transformation reaction (one mechanism for low temperature, and another for the complete temperature range considered). Kinetic parameters that were used for the disappearance of ethylbenzene during the transformation reaction, and in its conversion into cracking and disproportionation products, were calculated using the catalyst activity decay function, based on the time-on-stream (TOS). The apparent activation energies were determined to decrease: Ecracking > Edisproportionation. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801609x

Kinetic investigation of benzene ethylation with ethanol over USY zeolite in a riser simulator / Odedairo, T. in Industrial & engineering chemistry research, Vol. 49 N° 4 (Fevrier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1642–1651 Titre : Kinetic investigation of benzene ethylation with ethanol over USY zeolite in a riser simulator Type de document : texte imprimé Auteurs : Odedairo, T., Auteur ; Al-Khattaf, S., Auteur Année de publication : 2010 Article en page(s) : pp 1642–1651 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetic  Benzene  Ethylation  Zeolite. Résumé : The ethylation of benzene with ethanol over USY zeolite catalysts has been investigated at three different temperatures (300, 350, and 400 °C) for reaction times of 3, 5, 7, 10, 13, and 15 s with constant benzene to ethanol mole ratio of 1:1. Significant benzene conversion was found in the ethylation of benzene with ethanol over USY-2 catalyst as compared with the negligible conversion observed over USY-1 catalyst of lower acidity. The cracking of ethylbenzene (EB) was found to dominate at high temperatures (350 and 400 °C) in the ethylation of benzene with ethanol over USY-2 catalyst while ethylbenzene ethylation becomes significant at lower temperature (300 °C). Considerable amount of toluene was observed in the ethylation of benzene over USY-2 catalyst and was found to increase with increasing reaction temperature. The effect of reaction conditions on ethylbenzene selectivity, toluene selectivity, toluene-to-EB ratio, and total diethylbenzene (DEB) selectivity, are reported. Kinetic parameters for the ethylation of benzene with ethanol (E1), cracking of EB (E2), ethylation of ethylbenzene with ethanol (E3), and the cracking of diethylbenzene (E4) over USY-2 catalyst were determined using the catalyst activity decay function based on time-on-stream model. The apparent activation energies were found to decrease as follows: E2 > E3 > E4 > E1. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901526d [article] Kinetic investigation of benzene ethylation with ethanol over USY zeolite in a riser simulator [texte imprimé] / Odedairo, T., Auteur ; Al-Khattaf, S., Auteur . - 2010 . - pp 1642–1651. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1642–1651 Mots-clés : Kinetic  Benzene  Ethylation  Zeolite. Résumé : The ethylation of benzene with ethanol over USY zeolite catalysts has been investigated at three different temperatures (300, 350, and 400 °C) for reaction times of 3, 5, 7, 10, 13, and 15 s with constant benzene to ethanol mole ratio of 1:1. Significant benzene conversion was found in the ethylation of benzene with ethanol over USY-2 catalyst as compared with the negligible conversion observed over USY-1 catalyst of lower acidity. The cracking of ethylbenzene (EB) was found to dominate at high temperatures (350 and 400 °C) in the ethylation of benzene with ethanol over USY-2 catalyst while ethylbenzene ethylation becomes significant at lower temperature (300 °C). Considerable amount of toluene was observed in the ethylation of benzene over USY-2 catalyst and was found to increase with increasing reaction temperature. The effect of reaction conditions on ethylbenzene selectivity, toluene selectivity, toluene-to-EB ratio, and total diethylbenzene (DEB) selectivity, are reported. Kinetic parameters for the ethylation of benzene with ethanol (E1), cracking of EB (E2), ethylation of ethylbenzene with ethanol (E3), and the cracking of diethylbenzene (E4) over USY-2 catalyst were determined using the catalyst activity decay function based on time-on-stream model. The apparent activation energies were found to decrease as follows: E2 > E3 > E4 > E1. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901526d

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

Toluene disproportionation and methylation over zeolites TNU-9, SSZ-33, ZSM-5, and mordenite using different reactor systems / T. Odedairo 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. 3169-3183 Titre : Toluene disproportionation and methylation over zeolites TNU-9, SSZ-33, ZSM-5, and mordenite using different reactor systems Type de document : texte imprimé Auteurs : T. Odedairo, Auteur ; R. J. Balasamy, Auteur ; Al-Khattaf, S., Auteur Année de publication : 2011 Article en page(s) : pp. 3169-3183 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Reactor  Zeolite  Methylation  Disproportionation Résumé : An array of zeolites varying in the channel structural design and acidity was investigated in toluene methylation with methanol, together with toluene disproportionation, using fluidized-bed and fixed-bed reactors. The conversions of toluene in the methylation and disproportionation reactions in the fixed-bed reactor were higher than those in the fluidized-bed reactor over the zeolite based catalysts at similar reaction conditions. The unique pore architecture of zeolite TNU-9, with 10-ring channel systems, being slightly larger zeolite compared with ZSM-5, can offer new opportunities for toluene disproportionation, as well as for toluene methylation. The medium pore zeolite TNU-9 was found to possess the highest conversion in toluene disproportionation as compared with other zeolite based catalysts under study. In toluene methylation, the highest toluene conversion was achieved with mordenite based catalyst (MOR-A), while the xylene selectivity follows the order: ZSM-5 > TNU-9 > MOR-A > SSZ-33 > MOR-B. This order indicates that xylene selectivity is directly related to the size of channels from medium to large pore zeolites. Using the fluidized bed, the apparent activation energies for toluene methylation follow the order: ZSM-5 (46.8 kJ/mol) > TNU-9 (33.9 kJ/mol) > MOR-B (13.9 kJ/mol) ≈ MOR-A (13.1 kJ/mol) > SSZ-33 (8.2 kJ/mol). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944482 [article] Toluene disproportionation and methylation over zeolites TNU-9, SSZ-33, ZSM-5, and mordenite using different reactor systems [texte imprimé] / T. Odedairo, Auteur ; R. J. Balasamy, Auteur ; Al-Khattaf, S., Auteur . - 2011 . - pp. 3169-3183. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3169-3183 Mots-clés : Reactor  Zeolite  Methylation  Disproportionation Résumé : An array of zeolites varying in the channel structural design and acidity was investigated in toluene methylation with methanol, together with toluene disproportionation, using fluidized-bed and fixed-bed reactors. The conversions of toluene in the methylation and disproportionation reactions in the fixed-bed reactor were higher than those in the fluidized-bed reactor over the zeolite based catalysts at similar reaction conditions. The unique pore architecture of zeolite TNU-9, with 10-ring channel systems, being slightly larger zeolite compared with ZSM-5, can offer new opportunities for toluene disproportionation, as well as for toluene methylation. The medium pore zeolite TNU-9 was found to possess the highest conversion in toluene disproportionation as compared with other zeolite based catalysts under study. In toluene methylation, the highest toluene conversion was achieved with mordenite based catalyst (MOR-A), while the xylene selectivity follows the order: ZSM-5 > TNU-9 > MOR-A > SSZ-33 > MOR-B. This order indicates that xylene selectivity is directly related to the size of channels from medium to large pore zeolites. Using the fluidized bed, the apparent activation energies for toluene methylation follow the order: ZSM-5 (46.8 kJ/mol) > TNU-9 (33.9 kJ/mol) > MOR-B (13.9 kJ/mol) ≈ MOR-A (13.1 kJ/mol) > SSZ-33 (8.2 kJ/mol). DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=23944482

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