Kinetics of zeolite-catalysed toluene isopropylation

Abstract

The isopropylation of toluene to cymene was studied over medium-pore zeolite ZSM-5. The influence of the operating parameters on the product distribution was studied and a reaction mechanism already established was used to develop a kinetic model. At temperatures above 548 K negative apparent activation energies were obtained which were ascribed to the increased diffusion resistances at higher temperatures. Apparent activation energies were corrected to intrinsic activation energies by taking into account the heats of adsorption and the activation energy for diffusion.