Direct Synthesis of Diethyl Carbonate From Ethanol and Carbon Dioxide Using CexZr1-XO2 Catalysts

Direct synthesis of diethyl carbonate from ethanol and CO₂ is attractive since starting materials are cheap and easily obtainable, and the initial operational procedures are quite simple. We present results showing that Ce_xZr_1-xO₂ solid solution catalysts are effective and selective for producing diethyl carbonate and could be recyclable without loss of any activity. High calcination temperature is favorable based on results of catalytic test. X-ray diffraction and temperature-programmed desorption of NH_x and CO₂ provide evidence indicating that catalytic properties of Ce_xZr_1-xO₂ are closely dependent on the crystal structures and the acid–base sites on the surface with varied Ce/Zr ratios. Strong acid–base sites on the surfaces of catalysts are unfavorable for diethyl carbonate formation.