维生素C催化合成尼泊金甲酯

摘要

Methyl paraben is synthesized by p-hydroxybenzonic acid and methanol with Vitamin C as catalyst.The optimum conditions for synthesis are studied by investigating the effects of key factors in the experiment,such as molar ratio of alcohol to acid,catalyst amount and reaction time.The ex-perimental results show that the optimum conditions are determined as follows:molar ratio of alcohol to acid is 4∶1,reaction time is 4 h,and the amount of catalyst is 15%.Under the optimal conditions, the yield of the product is more than 92.3%.Meanwhile,compare the catalytic effects of Vitamin C, concentrate sulfuric acid and ionic liquids[H mim]+BF4 -,which shows that Vitamin C has a lot of advantages,such as high catalytic activity,green and environmental protection,without producing much waste acid and with low requirement for facilities.So it is one of the better catalysts for esterifi-cation reaction.%以维生素C为催化剂，以对羟基苯甲酸和甲醇为原料合成尼泊金甲酯。考察了醇酸摩尔比、催化剂的用量、反应时间等对酯产率的影响，并优化了合成工艺条件。实验结果表明：最优合成条件为醇酸的摩尔配比4∶1，反应时间4 h，催化剂的用量为对羟基苯甲酸质量的15％。在最优合成条件下酯的产率可达到92．3％。同时，比较了维生素C与浓硫酸和液体离子[H mim]＋BF4-的催化酯化效果，表明维生素C具有催化活性高、绿色、环保、不产生废酸、对设备要求不高等优点，是酯化反应较好的催化剂之一。