Direct Synthesis Of Diethyl Carbonate From Carbon Dioxide, Ethanol And Epoxy Propane Over Catalysts

Diethyl carbonate(DEC) has the extremely widespread application prospect, because DEC was a kind of environmentally friendly chemical product. At present, the synthesis method of DEC has many insufficients, such as low catalyst activity, high toxicity, high prices of raw material and lower productivity. Direct synthesis of DEC from carbon dioxide and ethanol was received extensive attention at home and abroad. Using CO2 as a raw material in chemical reaction meets the requirement of green chemistry.The effect of the performance for the catalyst on the direct synthesis of DEC from carbon dioxide-ethanol-epoxy propane was studied, including the selection of catalysts and the preparation methods of catalysts. When the cerium oxide(Ce O2) was used as the catalysis, the yield of DEC was lower, only 0.27%. The multi-component catalysts were further prepared, and the relationship between the structure and catalytic activity was investigated.The Ce O2 was prepared by the precipitation method from Ce(NO3)3. Then different oxide was loaded onto the Ce O2 catalyst, and the K2O-Ce O2 was selected finally. The catalysts were characterized by the XRD, BET, TEM, and TGA methods, which could help to analyze the influence of the catalyst structures on the catalytic performances. It was demonstrated that the K2O-Ce O2 catalyst with 20% K2O(mol %), calcined at 500°C, had better catalytic activity. Under the optimal conditions: temperature of 150°C, pressure of 7MPa, reaction time of 2h, CO2: Ethanol: PO=0.29:0.17:0.14(mol/mol), the DEC yield was 2.1 mmol. The DEC yield was about 10-fold as that with Ce O2 catalyst.The Ce O2-KBr-KNO3 was prepared by volume impregnation method. The yield of DEC was increased further. It was demonstrated that Ce O2: KBr: KNO3 = 1: 0.6: 0.4(g/g), and calcined at 400°C, The catalyst had much better activity and the DEC yield was improved to 2.9%.