Effect of magnesium in the conversion of methanol on chryso-zeolite or zeolite ZSM-5 catalysts

Abstract

Methanol can be converted to a wide range of hydrocarbons using zeolite or chryso-zeolite ZSM-5 type catalysts. Chryso-zeolite ZSM-5 catalysts, which were prepared from asbestos fibers, were found to be active and very selective in the conversion of methanol when compared to a “pure” zeolite ZSM-5. Their peculiar catalytic properties were essentially related to the presence of magnesium coming from the asbestos microstructure. The amount of magnesium extracted from the fibers before the zeolite hydrothermal synthesis influenced the particle size, the selectivity and particularly the adsorption/desorption properties of the catalysts. The presence of a basic site generated by the magnesium led to catalysts with controlled selectivity and activity under normal reaction conditions.