Studies on the Hydroalkylation of Benzene and Methylbenzenes in the Presence of a Combination Catalyst of Pd-Al₂O₃ and NaCl-AlCl₃

Abstract

The mechanism of the hydroalkylation of benzene and methylbenzenes to cyclohexylbenzenes was studied in the presence of a palladium-fused salt (NaCl-AlCl₃) catalyst under hydrogen pressure. The activities of the hydrogenation catalyst and the alkylation catalyst were each estimated kinetically. The activity of the fused salt was compared with that of anhydrous aluminum chloride for the alkylation of aromatic compounds. The rate constants and Arrhenius parameters of the hydrogenation on palladium and the alkylation on the fused salt supported the presence of the cyclohexyl cation as an intermediate species in the hydroalkylation.