Urea methanolysis to dimethyl carbonate over ZnO–CeO2–MO (MO: La2O3, Y2O3, Co2O3, Ga2O3, and ZrO2) catalysts

A series of ZnO(0.64)–CeO2(0.26)–MO(0.1) (MO: La2O3, Y2O3, Co2O3, Ga2O3, and ZrO2) and ZnO(0.7)–CeO2(0.3) catalysts with a fixed molar composition (value in parenthesis) were prepared by a sol–gel method for use in the urea methanolysis to dimethyl carbonate (DMC). Effect of acidity and basicity of ZnO(0.64)–CeO2(0.26)–MO(0.1) on the catalytic performance was investigated. Experimental results revealed that basicity of the catalysts played more important role in determining the catalytic performance than acidity. Yield of DMC increased with increasing basicity of the catalyst. Among the catalysts tested, ZnO(0.64)–CeO2(0.26)–La2O3(0.1) with the largest basicity exhibited the best catalytic performance (50.4% of DMC yield).