Synthesis of pharmaceutical intermediates by toluene benzylation over heteropoly acids on different support

Abstract

Selective formation of pharmaceutical intermediates like diphenylmethane, dimethyl-diphenylmethane, benzyl toluene and benzole acid by liquid phase, toluene benzylation with benzyl chloride as a benzylating agent, was systematically studied over plane clay (K-10, montmorillonite), plane H-Beta, plane MFI structured titanosilicate (TS-1) and heteropoly acids [HPA, namely dodeca-tungstophosphoric acid [H₃PO₄·-12WO₃·x H₂O] (TPA), dodeca-molybdo phosphoric acid ammonium salt hydrate [H₁₂Mo₁₂N₃O₄₀P+aq] (DMAA), sodium tungstate hydrated purified [Na₁₂WO₄-2H₂O] (STH)] supported on clay, H-beta and TS-1. The 20%TPA/Clay, 30%TPA/H-Beta and 30%TPA/TS-1, were observed to be the best catalyst samples over plane clay, plane H-Beta and plane TS-1. The catalyst samples are compared with respect to benzyl chloride conversion and selectivities for diphenylmethane, dimethyl-diphenylmethane, benzyl toluene and benzole acid. The reaction follows the pseudo-first order rate power law model. The apparent rate constants are calculated and compared with the reported ones.