以磷钨酸为催化剂的丁二酸二丁酯的合成及其动力学研究

Study on Synthesis of Dibutyl Succinate Catalyzed by Phosphtungstic Acid and its Reaction Kinetics

采用磷钨酸为催化剂、甲苯为带水剂,以丁二酸和丁醇合成丁二酸二丁酯。利用均匀设计实验考察醇酸摩尔比、带水剂用量、催化剂用量、反应时间因素对收率的影响,筛选出最佳工艺条件:醇酸摩尔比为3.0:1;催化剂用量为酸质量的1.1%;带水剂用量为体系总质量的22%;反应时间为2h,丁二酸二丁酯收率可达99.47%以上。对实验数据进行回归处理,获得不同反应条件下动力学参数,结果表明,该酯化反应服从二级不可逆动力学模型。反应表观活化能Ea=80.435kJ·mol-1,指前因子k0=7.066×108mol-1·L·min-1。

Dibutyl succinate was synthesized by using succinate acid and n-butanol as reactants, phosphotungstic acid as catalyst and toluene as azeotropic agent. The optimum synthesis conditions affecting the yield of dibutyl succinate, such as the amount of catalyst, molecular ratio of n-butanol to succinate acid, amount of azeotropic agent used and reaction time, were investigated by the experiments according to uniform design. The results indicate that 99.47% yield of dibutyl succinate could be obtained with following optimal reaction conditions： the molecular ratio of n-butanol to succinate acid 3.0：1, the amount of catalyst 1.1% by mass of acid, the amount of azeotropic used 22% of total mass and the reaction time 2 h. The kinetic parameters, such as the apparent activation energy Ea and the frequency factor k0, were obtained by regression of the experimental data achieved under various reaction conditions, and the kinetic equation of the esterification reaction was proposed. According to the kinetic equation proposed, the synthetic reaction of dibutyl succinate is a second order irreversible reaction. The proposed kinetic equation was also examined by the experimental results and got a satisfactory result.