Synthesis Of Diethy Carbonate From Carbon Dioxide Over Zr_x/(Fe-Ce)

As global warming becomes more and more serious,the carbon dioxide storage and utilization has become a global problem.The production of chemicals using carbon dioxide as a renewable carbon source could mitigate climate change.The main components of the stripping fermentation gas are carbon dioxide and ethanol,which is a very suitable raw material for the synthesis of diethyl carbonate.In this paper,Zrx/(Fe-Ce)was used as the catalyst to synthesize diethyl carbonate using carbon dioxide and the exhaust gas of fermentation as raw materials respectively.Additionally,the glycerol carbonate was synthesized from diethyl carbonate and its biodegradability was investigated.The specific results are as follows:1.Zrx/(Fe-Ce)was prepared by the co-precipitation method,and the optimal preparation conditions were obtained after screening.When ZrOCl2,Ce(NO3)3,Fe(NO3)3 are used as precursors,Zr/(Fe+Ce)is 0.1,the precipitation temperature is 50℃,the precipitation pH value is 10,and the calcination temperature is 800℃,the highest catalytic activity can be obtained.2.The diethyl carbonate was synthesized from carbon dioxide and the exhaust gas of ethanol fermentation respectively and the optimum reaction conditions were investigated.There is little difference between the two optimal reaction conditions.The same optimal reaction conditions are as follows:the reaction temperature is 170℃,the pressure is 4.5 MPa,the ethanol dosage is 4 mL,the catalyst dosage is 0.20 g.However,the optimal reaction time of CO2 synthesis of diethyl carbonate is 3 h,and that of the exhaust gas of ethanol fermentation is 2.5 h.The optimal selectivity and yield of the former is 96.69%and 3.78 mg/mL,respectively,while those of the latter are 56.65%and 0.32 mg/mL,respectively.The addition of dehydrating agent can promote the reaction to proceed forward.The catalyst can be reused for 3 times,indicating good reuse rate.3.The glycerol carbonate was synthesized by diethyl carbonate and glycerol.The conversion rate of glycerol reaches 90.67%,and the selectivity reaches 97.23%.The biodegradability of glycerol carbonate was investigated through biodegradation experiment of activated sludge.The degradation rate could reach more than 90%in three days,which proves the good biodegradability.