甲苯-4-磺酸催化高效合成尼泊金正丁酯防腐剂

摘要

n-Butyl-p-hydroxybenzoate was synthesized from p-hydroxybenzoic acid and n-butanol with tolu-ene-4-sulfonic acid as catalyst and n-butanol as water entrainer. Effects of molar ratio of p-hydroxybenzoic acid to n-butanol,reaction temPerature and reaction time,etc. on the yield of the Product were studied. The result showed that the suitable reaction conditions were as follows:based on 0 . 02 mole p-hydroxy-benzoic acid,n-butanol/p-hydroxybenzoic acid molar ratio of 4: 1,toluene-4-sulfonic acid/p-hydroxy-benzoic acid mass ratio of 0 . 12:1 ,reaction temPerature 140 ℃,for 3 h reaction time give the highest yield of n-butyl-p-hydroxybenzoate above 99%.%以对羟基苯甲酸和正丁醇为主要原料，甲苯-4-磺酸为催化剂，正丁醇为带水剂，催化合成尼泊金正丁酯。考察了原料对羟基苯甲酸和正丁醇的摩尔比、催化剂用量、反应温度和反应时间等对反应的影响。结果表明，适宜的反应条件：以0.02 mol对羟基苯甲酸计，n（正丁醇）：n（对羟基苯甲酸）＝4：1，m（甲苯-4-磺酸）：m（对羟基苯甲酸）＝0.12：1，反应温度140℃，反应时间3 h。该条件下，重复实验3次，尼泊金正丁酯收率均达99%以上。