Direct Production of Propene from Methoxy Species and Dimethyl Ether over H-ZSM-5

The mechanism of the initial C-C bond formation on methanol to olefin (MTO) and/or methanol to hydrocarbon (MTHC) reaction were not clarified. In this paper, the reaction mechanism and the reactivity of methoxy species on H-ZSM-5 zeolite with methanol or dimethyl ether (DME), which is the initial product of MTO and MTHC reactions, were observed by infrared (IR) spectroscopy. The direct production of propene from methoxy groups and DME is evidenced on H-ZSM-5 zeolite by isotopic studies of IR observation of surface species and GC-mass analysis of products. Stepwise reactions of DME to ethene and water followed by methylation of ethene by methoxy groups were negligible during the generation of propene by the reaction of methoxy groups and DME.