关键词: 丁二酸二甲酯, 离子液体, 酯化反应, 催化剂, 反应机理

Abstract: Seven kinds of ionic liquids, N-methyl-imidazolium bisulfate（［Hmim］HSO₄),1-butyl-3-methyl imidazole phosphate（［Bmim］H₂PO₄), 1-butyl-3-methyl imidazole bisulfate(［Bmim］HSO₄), 1-butyl-3-methyl imidazole tetrafluoroborate（［Bmim］BF₄), N-butyl-pyridine bisulfate（［Bpy］HSO₄), N-butyl-pyridine phosphate（［Bpy］H₂PO₄), N-ethyl-pyridine bisulfate（［Epy］HSO₄), were designed and synthesized.The synthesis of dimethyl succinate catalyzed by ionic liquids was studied for the first time.It was shown that［Epy］HSO₄ had the best catalytic performance, and optimal conditions for the synthesis of dimethyl succinate were obtained, succinic acid and methanol molar ratio 1∶3.0, amount of catalyst 5%（g/g)of succinic acid, reaction temperature 70℃ and reaction time 2 h.Under the optimal conditions, the yield of dimethyl succinate was up to 91.83%, esterification rate was 96.32%.The catalyst was recycled 7 times without substantial decrease in activity.Moreover, compared to conventional industrial catalysts, ionic liquid catalyst had the superiority of smaller catalyst dosage, less by-product, mild reaction conditions, high yield, and recycled catalyst usage.Finally, the mechanism of esterification catalyzed by ionic liquids was discussed.

Key words: dimethyl succinate, ionic liquid, esterification, catalyst, reaction mechanism