Highly active Si-MCM-41-Supported Ga2O3 and In2O3 catalysts for Friedel-Crafts-type benzylation and acylation reactions in the presence or absence of moisture

Ga2O3 and In2O3 (which are amphoteric and basic in nature, respectively) supported on mesoporous Si-MCM-41, or even on micro- or macroporous inert catalyst carriers, are highly active and reusable catalysts for the benzylation of benzene and acylation of aromatic compounds, even in the presence of moisture. Moisture has a beneficial effect, more particularly for the acylation reaction. It causes an increase in the reaction rates for both the reactions and also a large increase in the induction period for the benzylation reaction but not for the acylation. The induction period is due to the presence of moisture adsorbed on the catalyst, which is to be replaced by the reactant(s) to start the catalytic reaction. (C) 2000 Academic Press.