BENZYLATION OF BIPHENYL WITH BENZYL-CHLORIDE OVER HY ZEOLITES - A KINETIC-MODEL FOR REACTION AND CATALYST DEACTIVATION

Two dealuminated HY zeolites were employed as catalysts for the Friede l-Crafts reaction of biphenyl with benzyl chloride in a slurry batch r eactor, with solvents cyclopentane, cyclohexane, and methylcyclohexane , at temperature from 50 to 100 degrees C. Mainly benzylbiphenyl isome rs (M), but also appreciable quantities of dibenzyl derivatives (D) we re obtained and determined. Within the monobenzylated fraction, a para -selectivity of 65-70% at 60% conversion was reached. Magnetic stirrin g was found to be adequate for a chemically controlled reaction kineti cs. Kinetic models, including equations for the process itself and for the catalyst deactivation, and applied on the basis of optimization p rocedures, were used to correlate the results. The model of choice was able to interpret runs carried out at different doses of catalyst and different initial concentrations of the benzylating agent. A solvent effect on the kinetics was evidenced. Deactivated catalysts were regen erated for a few reaction-regeneration cycles.