Case study on 4-Isopropyl-ortho-xylene production

Abstract

We have experimentally studied the alkylation reaction of o-xylene with propylene under kinetic control conditions followed by realkylation under thermodynamic control conditions. The paper provides an analysis of the alkylation reaction products obtained under kinetic control as well as kinetic analysis and thermodynamic analysis of the overalkylation process. The authors have considered the methyl group migration reactions during overalkylation and have given kinetic analyses of these reactions. We found that the optimal method for the preparation of 4 isopropyl-o-xylene is to conduct the process in two stages. The first one is a liquid-phase alkylation of o-xylene under kinetic control at 353 K. The second stage is liquid-phase realkylation of the obtained alkylation reaction mass until reaching thermodynamic equilibrium at a temperature range of 303-353 K under certain conditions. These conditions should ensure minimal migration of methyl groups, i.e. with minimum contact time and alkyl-/aryl- < 0.5 ratio in the reaction products.