Mechanistic studies on the transformation of ethanol into ethene over Fe-ZSM-5 zeolite.

Thana Maihom, Pipat Khongpracha, Jakkapan Sirijaraensre, Jumras Limtrakul

Laboratory for Computational and Applied Chemistry, Department of Chemistry, Faculty of Science and Center of Nanotechnology, Kasetsart University Research and Development Institute, Kasetsart University, Bangkok 10900, Thailand.

Chemphyschem : a European journal of chemical physics and physical chemistry 2013 Jan 14

filter terms:

Ethanol, through the utilization of bioethanol as a chemical resource, has received considerable industrial attention as it provides an alternative route to produce more valuable hydrocarbons. Using a density functional theory approach incorporating the M06-L functional, which includes dispersion interactions, a large 34T nanocluster model of Fe-ZSM-5 zeolite in which T is a Si or Al atom is employed to examine both the stepwise and concerted mechanisms of the transformation of ethanol into ethene. For the stepwise mechanism, ethanol dehydration commences from the first hydrogen abstraction of the ethanol OH group to form the ethoxide-hydroxide intermediate with a low activation energy of 17.7 kcal mol(-1). Consequently, the ethoxide-hydroxide intermediate is decomposed into ethene through hydrogen abstraction from the ethoxide methyl carbon to either the OH group of hydroxide or the oxygen of the ethoxide group with high activation energies of 64.8 and 63.5 kcal mol(-1), respectively. For the concerted mechanism, ethanol transformation into the ethene product occurs in a single step without intermediate formation, with an activation energy of 32.9 kcal mol(-1). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Citation

Thana Maihom, Pipat Khongpracha, Jakkapan Sirijaraensre, Jumras Limtrakul. Mechanistic studies on the transformation of ethanol into ethene over Fe-ZSM-5 zeolite. Chemphyschem : a European journal of chemical physics and physical chemistry. 2013 Jan 14;14(1):101-7