Kinetic study for ionic liquid catalyzed green O-methylation of cresols using dimethyl carbonate

Abstract

In this work, we have systematically studied the kinetics and mechanism of ionic liquid catalyzed solvent less liquid-phase O-methylation of p-cresol with dimethyl carbonate (DMC). The effect of various parameters such as mass transfer resistance, catalyst loading, mole ratio, initial CO2 pressure, and temperature was studied. The reaction was found to be pseudo zero order with respect to p-cresol and first order with respect to DMC. o- and m-Cresols were also used. The values of apparent activation energy for o-, m-, and p-cresol are found as 32.5, 34.0, and 32.5 kcal/mol, respectively. Our study also suggests that type of cation and anion affects the catalytic acitivity of ionic liquids. Ionic liquid, tetra butyl phosphonium bromide, offers excellent activity, selectivity, reusability, recyclability and stability.