碳酸二甲酯与乙醇酯交换反应动力学

Reaction Kinetics of Trans-Esterification between Dimethyl Carbonate and Ethanol

在间歇反应釜内,以甲醇钠为催化剂,对碳酸二甲酯与乙醇酯交换合成碳酸二乙酯反应进行了研究,考察了催化剂浓度、反应温度、乙醇与碳酸二甲酯的摩尔配比等因素对酯交换反应的影响,通过数据校正优化了实验原始数据,建立了动力学模型并进行严格的模型检验,得到了可靠的模型参数。结果表明,该反应为连串反应,中间产物为碳酸甲乙酯,反应焓分别为ΔH10=-1.595 kJ?mol-1,ΔH20=0.809 kJ?mol-1;两个反应均为可逆反应,活化能分别为Ea1+=45.633 kJ?mol-1和Ea1-=47.228 kJ?mol-1、Ea2+=55.058 kJ?mol-1和Ea2-=54.249 kJ?mol-1。

The synthesis of diethyl carbonate using dimethyl carbonate and ethanol and catalyzed by sodium methoxide was studied experimentally in a batch stirred tank reactor. The effects of catalyst dosage, temperature, and molar ratio of ethanol to dimethyl carbonate on trans-esterification were investigated. A kinetic mathematical model was built to describe the reaction. It is found that the reaction consists two parts, and the intermediate product is methyl ethyl carbonate. The reaction heat is -1.595kJ·mol-1 for the first trans-esterification reaction and 0.809 kJ·mol-1 for the second one. Both of them are reversible. The forward and reverse activation energies of the first reaction are 45.633 kJ·mol-1 and 47.228 kJ·mol-1, respectively, while the second one shows that of 55.058 kJ·mol-1 and 54.249 kJ·mol-1, respectively.