The Research Of Diethyl Carbonate From Carbon Dioxide-ethanol Over Cerium Oxide/Molecular Sieve Catalysts

Diethyl carbonate (DEC) has the extremely widespread application prospect, becauseDEC is a kind of environmentally friendly chemical product. The reasonable utilization ofCO2has made a significant contribution to improve the environment, that it not only relievesthe energy crisis, but also reduces emissions of carbon dioxide. Direct synthesis of DEC bycerium oxide (CeO2) and3A molecular sieves from carbon dioxide-ethanol was studied,including the selection of catalysts and the preparation methods of catalysts.Cerium oxide and3A molecular sieves had effective catalytic activity for the directsynthesis of DEC from carbon dioxide and ethanol in this work. The CeO2was prepared byprecipitation method from Ce(NO3)3and calcined at600℃.Then the CeO2was mixed withthe3A molecular sieves which was dried at100℃before using. When CO2and ethanol werecharged with343.2mmol and223.7mmol,0.152mmol DEC was obtained at the optimalconditions:0.3g CeO2,1.0g3A molecular sieves, reaction pressure of7Mpa, reactiontemperature of150℃, reaction time of2h. The main by-product was found to be Acetal, andthe selectivity was up to86.1%.In addition, the ethylene was tried to introduce into the reaction as a dehydrating agent. Itis indicated that when ethylene of14.48mmol was added, there was no new by-productproduced, but both of the DEC yield (0.142mmol) and selectivity (80.3%) decreased.The catalysts were characterized by the XRD, BET, TEM, and TGA methods, whichcould help to analyze the influence of the catalyst structure on the catalytic performance. It isdemonstrated that the CeO2has a cubic fluorite structure, and it has good pore structure.Furthermore, it was also indicated that there was no direact correlation between the specificsurface area and the catalytic activity in this reaction.