The Friedel-Crafts reaction of biphenyl with benzyl chloride in cyclohexane was carried out in a slurry batch reactor, under magnetic stirring, over solid acid catalysts of amorphous or mesoporous MCM-41 aluminosilicates. Mainly benzylbiphenyl isomers (M), but also some dibenzyl derivatives (D), were obtained and determined. The chemically controlled reaction kinetics corresponded to two consecutive reactions. Kinetic models were applied on the basis of an optimization procedure, and the behavior of the amorphous silica-alumina and of the mesoporous aluminosilicates was compared with that of other materials, among which were HY zeolites, previously used as catalysts.