Influence of the Pore Geometry of Medium Pore Zeolites ZSM-5, -22, -23, -48 and -50 on Shape Selectivity in Reactions of Aromatic Hydrocarbons

Abstract

The isomerisation of meta xylene and methylation of toluene over ZSM-5, -22, -23, -48 and -50 reveal significant differences in shape selectivity amongst these medium pore zeolites. Both reactant/product shape selectivity as well as restricted transition state shape selectivity differ along the above series. It is concluded that in addition to the size of the pore openings, other parameters of pore geometry (like shape, the dimensionality of the pore system and the presence/absence of pore intersections and side pockets) have a significant effect on the shape selectivity of zeolites in catalysis.