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Role of acidity in the ethylation of coking benzene with ethanol over nanosized HZSM-5 / Sun, Linping in Industrial & engineering chemistry research, Vol. 49 N° 2 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 506–514 Titre : Role of acidity in the ethylation of coking benzene with ethanol over nanosized HZSM-5 Type de document : texte imprimé Auteurs : Sun, Linping, Auteur ; Xinwen Guo, Auteur ; Liu, Min, Auteur Année de publication : 2010 Article en page(s) : pp 506–514 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Ethylation  Zeolites  Thermogravimetry  Dimethylpyridine. Résumé : Ethylation of coking benzene, the product of coke oven gas, with ethanol over nanosized HZSM-5 zeolites poisoned by 2,6-dimethylpyridine has been investigated in a fixed-bed reactor. Pyridine infrared (Py-IR), amonia temperature programmed desorption (NH3-TPD), thermogravimetry (TG), acidity titration with a Hammett indicator, and cyclohexane and n-hexane adsorption were used to characterize the changes in acidity and porosity of the nanosized HZSM-5 zeolites poisoned by 2,6-dimethylpyridine. Conversion and product distribution depend strongly on the degree of catalyst poisoning. The acidity−activity correlation indicates that acid sites with pKa < −3.0 are responsible for the ethylation of coking benzene and sites with pKa < 2.27 are responsibly for the thiophene conversion. The remaining acid sites, which are not active for the ethylation of coking benzene over the poisoned sample, act as active centers for ethanol dehydration to ethylene. 2,6-Dimethylpyridine not only adsorbs on the strong Brnsted acid sites but blocks the zeolite channels over the poisoned sample. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901218j [article] Role of acidity in the ethylation of coking benzene with ethanol over nanosized HZSM-5 [texte imprimé] / Sun, Linping, Auteur ; Xinwen Guo, Auteur ; Liu, Min, Auteur . - 2010 . - pp 506–514. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 506–514 Mots-clés : Ethylation  Zeolites  Thermogravimetry  Dimethylpyridine. Résumé : Ethylation of coking benzene, the product of coke oven gas, with ethanol over nanosized HZSM-5 zeolites poisoned by 2,6-dimethylpyridine has been investigated in a fixed-bed reactor. Pyridine infrared (Py-IR), amonia temperature programmed desorption (NH3-TPD), thermogravimetry (TG), acidity titration with a Hammett indicator, and cyclohexane and n-hexane adsorption were used to characterize the changes in acidity and porosity of the nanosized HZSM-5 zeolites poisoned by 2,6-dimethylpyridine. Conversion and product distribution depend strongly on the degree of catalyst poisoning. The acidity−activity correlation indicates that acid sites with pKa < −3.0 are responsible for the ethylation of coking benzene and sites with pKa < 2.27 are responsibly for the thiophene conversion. The remaining acid sites, which are not active for the ethylation of coking benzene over the poisoned sample, act as active centers for ethanol dehydration to ethylene. 2,6-Dimethylpyridine not only adsorbs on the strong Brnsted acid sites but blocks the zeolite channels over the poisoned sample. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901218j