Oxidative dehydrogenation of ethylbenzene over supported iron oxide by using CO2 as an oxidant

Oxidative dehydrogenation of ethylbenzene with carbon dioxide has been carried out over gamma-Al2O3-supported iron oxide catalyst as well as commercial catalyst (K-Fe2O3) for comparison. In the dehydrogenation over the gamma-Al2O3-supported iron oxide catalyst, carbon dioxide is found to play a key role as an oxidant for promoting catalytic activity. The enhancement of the dehydrogenation activity in the presence of carbon dioxide is certainly ascribed to the promotion of this oxidative process by excess carbon dioxide. On the other hand, the commercial catalyst exhibits considerable decrease in catalytic activity under the same condition. It is suggested that an active phase for the dehydrogenation with carbon dioxide over gamma-Al2O3-supported iron oxide catalyst would be rather a reduced and isolated magnetite (Fe3O4)-like phase having oxygen deficiency in the alumina support matrix.