在工业甲醇与粗菜籽油摩尔比为6:1、KOH催化剂质量分数0.5%(基于菜籽油)的条件下,在500mL高压搅拌反应釜中进行加压催化合成生物柴油的酯交换反应,研究了在反应温度高于甲醇常压沸点(64.5℃)时酯交换反应的动力学,采用最小二乘法回归实验数据,获得幂函数形式的加压催化条件下粗菜籽油与工业甲醇酯交换反应的宏观动力学模型。实验结果表明,酯交换反应的反应级数为1.86,反应活化能为23.493kJ/mol,与文献值相近,频率因子为2782min^-1。F检验表明,幂函数模型与实验数据吻合良好,说明该宏观动力学模型可用于描述加压催化下粗菜籽油与工业甲醇的酯交换反应。
Transesterification of crude rapeseed oil and methanol with KOH catalyst to produce biodiesel were carried out at temperatures higher than boiling point of methanol and pressure higher than atmospheric presure in a 500 mL batch reactor. The mole ratio of methanol to rapeseed oil was 6 : 1 and the concentration of catalyst was 0.5 % of rapeseed oil mass. Experimental data seem to be fit to a second-order kinetic equation, A macro-kinetic equation for the transesterification was established based on both the least square method and experimental data. In this equation, reaction order is 1.86, reaction rate constant is 2 782 min^-1 and activation energy is 23. 493 kJ/mol. Results of F-test show that the predicted values from the macro-kinetics equation are in accord with the experimental data. It denotes that the proposed equation can be applied to describe the kinetics of transesterification of crude rapeseed oil with methanol in batch reactor.