Benzylation of benzene in liquid phase by benzyl chloride to diphenylmethane over FeCl3, MnCl2, CoCl2, NiCl2, CuCl2, and ZnCl2 supported on acidic alumina (at 80degreesC) has been investigated. The redox property of alumina-supported transition metal chloride seems to play a very important role in the benzene benzylation process. Among the catalyst, the FeCl3/Al2O3 showed both high conversation and high selectivity for the benzylation of benzene. These catalysts can also be reused in the benzylation of benzene for several times. A plausible reaction mechanism for the benzene benzylation over the alumina-supported metal chloride catalysts is proposed. (C) 2003 Elsevier B.V. All rights reserved.