Synthesis of diphenyl carbonate from phenol and carbon dioxide in carbon tetrachloride with zinc halides as catalyst

Abstract

Synthesis of diphenyl carbonate (DPC) from phenol and CO 2 has been explored in CCl 4 with zinc halides as catalyst. DPC yield and selectivity are influenced by the catalyst usage, reaction temperature, CO 2 pressure and initial composition of reactants. The main byproduct is phenyl salicylate (PS). Zinc halides as Lewis acid exhibit high catalytic activity for DPC synthesis; ZnCl 2 gives higher DPC yield and selectivity than ZnBr 2 and ZnI 2. High DPC yield was obtained with ZnCl 2 as catalyst at 120 °C and 4.0 MPa. Based on the experimental observation, a possible reaction scheme has been proposed. The electronegativity of halogen ligand may determine the formation of DPC and PS; the Cl ligand in ZnCl 2 with strong electronegativity may favor the formation of DPC.