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Mechanistic Study of Ethanol Dehydrogenation over Silica‐Supported Silver
Author(s) -
Sushkevich Vitaly L.,
Ivanova Irina I.,
Taarning Esben
Publication year - 2013
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201300033
Subject(s) - dehydrogenation , chemistry , kinetic isotope effect , catalysis , hydride , acetaldehyde , photochemistry , reaction mechanism , bond cleavage , heterogeneous catalysis , infrared spectroscopy , hydrogen atom abstraction , fourier transform infrared spectroscopy , inorganic chemistry , ethanol , hydrogen , deuterium , organic chemistry , chemical engineering , physics , quantum mechanics , engineering
A silica‐supported Ag catalyst has been shown to be an efficient heterogeneous catalyst for the oxidant‐free dehydrogenation of ethanol into acetaldehyde. The reaction mechanism has been investigated by in situ FTIR spectroscopy. The kinetic isotope effects for proton and hydride abstraction have been studied by using CH 3 CD 2 OH and CH 3 CH 2 OD as labeled reactants. The results indicate that OH bond activation and the formation of a hydrogen‐bonded complex take place on the silica support and that the Ag particles are necessary for the activation of the CH bond. The kinetic isotope effect ( k H / k D ) is 1.9 for CH 3 CD 2 OH and 1.8 for CH 3 CH 2 OD. The concerted mechanism of CH cleavage on the Ag sites and proton abstraction on the silica sites is proposed to account for the results of the spectroscopic and kinetic experiments.