EVIDENCE OF AUTO-CATALYSIS IN METHANOL TO HYDROCARBON REACTIONS OVER ZEOLITE CATALYSTS

An analysis of the kinetic data for the conversion of methanol to hydrocarbons and the composition of light olefinic products suggests that autocatalytic reactions between methanol/dimethylether and olefins are important steps in the conversion process. Based on rate data obtained in an isothermal reaction system, the rate of higher olefin formation via an autocatalytic route is 50 times faster than the rate of initial formation of ethylene from methanol/dimethylether. This kinetic interpretation is supported by the observation that propylene instead of ethylene is the major hydrocarbon product at below 15% conversion (on a CH2 basis). A linear relationship exists between the intrinsic acid activity of the zeolite catalyst and the activity for methanol to hydrocarbon conversion. © 1979 Academic Press, Inc. All rights reserved.