Direct Synthesis of Diethyl Carbonate from CO2 and Ethanol Catalyzed by ZrO2/Molecular Sieve

The synthesis of diethyl carbonate starting from ethanol and carbon dioxide was studied. The ZrO 2 obtained by precipitation method was used as the catalyst. When the 3A molecular sieve was added as the co-catalyst, the DEC yield was effectively improved about 2.5-fold. The optimal mass ratio of ZrO 2 and 3A molecular sieve was 5:2. In addition, the catalyst was characterized by the means of XRD, BET, TEM, NH 3 -TPD and CO 2 -TPD. It was indicated that the crystal type, acidic-basic properties of ZrO 2 , and the pore size of molecular sieve might be the main factors impacting the catalytic activities. By the optimization of the catalyst and the reaction operating conditions, when CO 2 and ethanol were charged with the molar ratio of 514/225 mmol, the yield of DEC produced at 150 °C and 7.0 MPa was 0.384 mmol in 2 h with the selectivity of 85.1 %. Graphical Abstract