乙醇钠催化碳酸丙烯酯与乙醇酯交换反应动力学研究

以乙醇钠为催化剂,进行了碳酸丙烯酯与乙醇酯交换合成碳酸二乙酯联产1,2-丙二醇的动力学研究,考察了催化剂用量、反应温度、乙醇与碳酸丙烯酯的摩尔比等因素对酯交换反应的影响。实验结果表明,在308～313K、催化剂用量(质量分数,基于碳酸丙烯酯和乙醇的总质量)0.8%～1.0%、乙醇与碳酸丙烯酯的摩尔比8的条件下,碳酸丙烯酯的转化率可达到64%。建立了碳酸丙烯酯与乙醇酯交换反应的动力学模型,由实验数据通过Runge-Kutta法及最小二乘法估算了相应的模型参数,标准摩尔反应热为-16.86kJ/mol,活化能为31.29kJ/mol,指数前因子为1.9689×10~4。经统计检验结果表明,动力学模型在实验条件下是适用的。

Kinetics of Transesterification of Propylene Carbonate with Ethanol Catalyzed by Sodium Ethoxide

Synthesis of diethyl carbonate through transesterification of propylene carbonate with ethanol was carried out in the presence of C_2H_5ONa catalyst.Effects of catalyst dosage,mole ratio of ethanol to propylene and reaction temperatures on the transesterification were investigated.Under the appropriate conditions of catalyst dosage(mass fraction based on propylene carbonate and ethanol total mass)0.8%-1.0%,mole ratio of ethanol to propylene carbonate 8 and reaction temperature 308- 313 K,the conversion of propylene carbonate was 64%.The kinetics model for the transesterification was proposed.The model parameters were estimated through Runge-Kutta method and the least square method.Activation energy,standard molar reaction heat and pre-exponential factor for the transesterification were 31.29 kJ/mol,-16.86 kJ/mol and 1.9689×10~4,respectively.Statistical test showed the model calculation results were in good agreement with the experimental data