对甲苯磺酸铜催化氯乙酸与醇的酯化反应

Esterification of Chloroacetic Acid and Alcohols Catalyzed by Cupric p-Tolenesulfonate

合成了对甲苯磺酸铜,用热重分析仪和红外光谱分析仪对其表征。以对甲苯磺酸铜作为氯乙酸和异丙醇反应的催化剂,考察了醇酸摩尔比、催化剂用量、带水剂用量、反应时间对反应的酯化率的影响。实验表明:氯乙酸0.167 mol,醇酸摩尔比1.1:1,催化剂用量1.0摩尔百分数,反应时间2.5 h,反应温度85-90℃,环己烷(带水剂)的用量2.5 mL,酯化率可达97.0％。与SnCl4等Lewis酸催化剂比较.对甲苯磺酸铜具有较高的催化活性,且反应后易与产物分离。催化剂重复使用8次,酯化率仍达到94.6％。对甲苯磺酸铜在催化氯乙酸和其它醇的酯化反应中亦保持良好的催化性能,相应的酯化率大都高于90％。

Copper p-tolenesulfonate was synthesized and characterized by TG and FTIR. It was employed as the catalyst in the esterification of chloroacetic acid with isopropanol. The molar ratio of isopropanol and chloroacetic acid, the amount of catalyst, the amount water-carrying agent (cyclohexane) and reaction time were observed to influence the reaction results clearly. Under the conditions of 0.167 mol chloroacetic acid, the 1.1:1molar ratio of isopropanol to chloroacetic acid, 1.0 molar percentage of catalyst in chloroacetic acid, 2.5 h reaction time, 2.5 mL cyclohexane and reaction temperature 85-90℃, the yield of reaction was 97.0%. Compared with some Lewis acids such as SnCl4, copper p-tolenesulfonate exhibited higher catalytic activity and could be easily separated from the reaction mixture after reaction. After the catalyst was reused 8 times, the yield of isopropyl chloroacetate was 94.6%. Copper p-tolenesulfonate also exhibited high catalytic activity in the esterification of chloroacetic acid with other alcohols. In most cases, the yield of chloroacetate was higher than 90%.