An improved kinetic model for the reaction of biphenyl with benzyl chloride over an MCM-41 solid acid catalyst

Abstract

Several samples of a mesoporous MCM-41 aluminosilicate were synthesized and most of their properties were found to be well reproduced, slightly less so the catalytic activity in preliminary runs of the title reaction. Two of the samples were mixed, to obtain a solid acid catalyst for systematic runs. The reaction of biphenyl with benzyl chloride in cyclohexane at 80°C was carried out in a slurry batch reactor, over the MCM-41 catalyst. The concentration of benzyl chloride and of the products, benzylbiphenyl isomers (M) and some dibenzyl derivatives (D), was determined as a function of time, in runs where several values of the initial concentrations of both reactants were tested ( C BzCl 0 from 0.03 to 0.10 mol/l; C BIP 0 from 0.20 to 0.50 mol/l). Kinetic models were applied on the basis of an optimization procedure. The best interpretation of the results was given by a Langmuir–Hinshelwood model, taking into account the adsorption of both biphenyl and benzyl chloride, that compete for the same active sites of the catalyst.