O-Methylation of Phenol for High Selective Synthesis of Anisole over Calcium Oxide Catalyst

Abstract

In this article, a CaO-based catalyst was prepared by impregnating potassium salt on CaO to develop a highly efficient heterogeneous catalyst for highly selective synthesis of anisole (AN) from phenol and dimethyl carbonate by a O-methylation. KF/CaO catalysts are highly active and selective towards formation of anisole via methylation of phenol with the highest yield of 97.48% AN was obtained at 200°C. Various reaction parameters including KF loading, the amount of catalyst and the calcination temperature on the catalytic activity were investigated. Scanning electron microscopy (SEM), X-ray diffraction (XRD), BET, CO₂‑TPD and thermogravimetric (TG) were used to characterize the prepared catalyst. It was found that the high catalytic activity of CaO after modification with KF is associated with the structural aspects and the amount of basicity of the catalyst. Temperature programmed desorption of CO₂ and XRD studies revealed the K₂O species, a strong basic site formed by the substitution of the Ca²⁺ in CaO lattice by K⁺, might have great contribution for the high conversion of phenol and good selectivity of anisole.