Synthesis of dimethyl carbonate from urea and methanol over ZnO(X)–CeO2(1−X) catalysts prepared by a sol–gel method

ZnO(X)–CeO2(1−X) (X=0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0) catalysts were prepared by a sol–gel method with a variation of ZnO content (X, mol%), and they were applied to the synthesis of dimethyl carbonate from urea and methanol. To investigate the effect of acidity and basicity on the catalytic performance, NH3-TPD and CO2-TPD experiments were conducted. Experimental results revealed that basicity of the catalysts played more important role in determining catalytic performance than acidity. Yield for dimethyl carbonate increased with increasing basicity of the catalyst. Among the catalysts tested, ZnO(0.7)–CeO2(0.3) with the largest basicity exhibited the best catalytic performance.