Conversion of methanol into light hydrocarbons on erionite–offretite(T) zeolite

Abstract

The reaction of methanol on T-type zeolites has been studied at 400 °C in a flow reactor [weight hourly space velocity 1 g (methanol) per g (catalyst) per hour]. The results demonstrate the influence of decationization and dealumination of zeolites on catalytic lifetimes (maximum 4 h). To reduce the deactivation of HT zeolites by coke formation, Ni- and Pt-exchanged samples have been used, and the reaction has been studied in the presence of hydrogen. The deactivation of Pt-HT is much slower than that of HT but only paraffinic hydrocarbons are produced. Observations by infrared spectroscopy of the conversion of deuterated methanol in the 20–400 °C region are embodied in a mechanism of propylene formation invoking dimethyl ether, methoxy groups and zeolite-T hydroxy groups.