Influence of the Si/Al ratio and ZSM-5 crystallite size on the methylation of toluene

The alkylation of toluene with methanol over ZSM-5 was studied using crystallites of different dimensions and Si/Al ratios. The products of the reaction consisted of 70–80% xylenes. Some benzene and ethyltoluene are also formed. The formation of para-xylene was strongly influenced by the number of aluminium atoms per unit cell of the zeolite and the gel composition utilized in its preparation. For the conditions studied here, no relationship between the crystallite dimensions and the para-selectivity was observed.