固体超强酸Tm-SO_4^(2-)/TiO_2催化合成柠檬酸三丁酯

Synthesis of tributyl citrate catalyzed by solid superacid Tm-SO_4^(2-)/TiO_2

制备固体超强酸催化剂Tm SO2-4/TiO2,应用于柠檬酸和正丁醇的酯化反应,与浓硫酸和SO2-4/TiO2等不同催化剂进行比较,并通过单因素实验对酸醇摩尔比、催化剂用量和反应时间等酯化反应条件进行了优化。实验结果表明,Tm SO2-4/TiO2的催化性能优于其他催化剂,用于合成柠檬酸三丁酯反应的柠檬酸转化率达94 4%,柠檬酸三丁酯选择性为99 2%,产率达93 6%,产品纯度>99%。重复使用5次后,催化活性仍高达93 1%。Tm SO2-4/TiO2催化合成柠檬酸三丁酯的最佳合成条件为n(柠檬酸)∶n(正丁醇)=1∶4,反应时间3 5h,催化剂用量占总投料量的质量分数为1 5%。

Solid superacid catalyst TmSO2-4/TiO2 was prepared and applied to esterification reaction of citric acid with butanol and compared with other catalysts such as sulfuric acid and SO2-4/TiO2. The reaction condition including initial citric acid/ butanol molar ratio, reaction time and catalyst amount were optimized. The results showed that TmSO2-4/TiO2 exhibited better catalytic properties than other catalysts, with citric acid conversion of 944%, selectivity to TBC of 992%, ester yield of 936% and product purity of over 99%. Citric acid conversion remained up to 931% after five runcycles. It was shown that the optimum synthesis condition for TBC over TmSO2-4/TiO2 were as follows: citric acid : butanol = 1∶4(molar), reaction time 35 h, catalyst amount = 15% (wt) of the amount of starting materials.