【摘要】 通过在线取样法研究了三羟甲基丙烷分别和正庚酸、正辛酸、正壬酸的真空自催化酯化过程及反应动力学，获取了分步酯化的反应动力学参数，建立了反应动力学模型，分析了羧酸种类和反应温度对酯化率及产品性能的影响。结果表明：采用真空自催化酯化法合成三羟甲基丙烷酯无需催化剂，当反应温度为200～230℃、反应时间为5 h时，酯化率可达到90%以上，三酯摩尔分数可达到80%～97%；该反应为吸热反应，各步反应的活化能为19～44 kJ·mol^-1，建立的动力学模型计算值与实验值吻合较好；烷基链越长，反应越困难，酯化率越低，产品的三酯摩尔分数、运动黏度、黏度指数、闪点越高；提高反应温度有利于三酯的生成，在一定范围内温度对产品的性能影响较小。更多还原

【Abstract】 The vacuum autocatalytic esterification process and reaction kinetics of trimethylolpropane with n-heptanoic acid, octanoic acid, and nonanoic acid were studied using online sampling method. The reaction kinetics parameters of the stepwise esterification were obtained, and a reaction kinetics model was established. The influence of carboxylic acid type and reaction temperature on esterification rate and product properties was analyzed. The results showed that the synthesis of trimethylolpropane ester by vacuum self-catalytic esterification method did not require catalyst, when the reaction temperature was 200～230 ℃ and the reaction time was 5 h, the esterification rate was over 90%, and the mole fraction of triester reached 80%～97%. This reaction was an endothermic reaction, with activation energies ranging from 19 kJ·mol^-1 to 44 kJ·mol^-1 for each step. The calculated values from the established kinetic model were in good agreement with the experimental values. The longer the alkyl chain, the more difficult the reaction, the lower the esterification rate, and the higher the mole fraction, kinematic viscosity, viscosity index, and flash point of the product’s trimester. Raising the reaction temperature was beneficial for the formation of triglycerides, and the temperature had little effect on the performance of product within a certain range.更多还原