尿素醇解合成碳酸二乙酯的热力学分析

THERMODYNAMICS ANALYSIS OF ALCOHOLYSIS OF UREA WITH ETHANOL

采用Benson基团贡献法,计算了在常压和温度353～453 K反应条件下,尿素醇解合成碳酸二乙酯反应的焓变、熵变、吉布斯自由能变。对尿素和乙醇制备碳酸二乙酯的过程进行了热力学分析,计算了醇解反应的平衡常数。结果表明,由尿素醇解合成碳酸二乙酯反应在热力学上是可行的,但反应的热力学平衡常数小。

For the reaction of preparing diethyl carbonate （DEC） from urea and ethanol, standard molar formation enthalpy, standard molar entropy and molar heat capacity under constant pressure of reagents were evaluated by the Benson method of group contribution at the range of 353 - 453 K. The thermodynamics of the reaction for the synthesis of diethyl carbonate from ethanol and urea was studied and the equilibrium constant was evaluated according to the chemical thermodynamic principle. The results showed that the preparation of DEC from urea and ethanol is thermodynamically possible. To overcome the low thermodynamic equilibrium constant limitation, the by-product ammonia must be removed instantly to enhance DEC yield.