酸性离子液体［HSO3-bpy］CF3SO3催化合成MDC

制备了一系列磺酸吡啶功能化酸性离子液体(ILs)，采用Hammett指示剂与紫外联用法测定了其酸强度。考察了各酸性离子液体在苯氨基甲酸甲酯(MPC)与甲醛缩合制备二苯甲烷二氨基甲酸甲酯(MDC)反应中的催化活性。结果表明，离子液体的酸强度与其催化活性关联较好;［HSO₃-bpy］CF₃SO₃酸强度最高，催化活性也最好。以［HSO₃-bpy］CF₃SO₃为催化剂兼溶剂，优化了MDC合成反应条件。在反应温度70℃，反应时间60 min，MPC与甲醛的摩尔比为12，离子液体与MPC的质量比为4的条件下，MDC产率最高可达91.5％。用水处理反应液，通过减压蒸馏后的离子液体可以循环使用5次以上。

MDC synthesis reaction catalyzed by CF3SO3 ionic liquid

A series of sulfonic acid-functional ionic liquids (ILs) were prepared and their acid strength was determined by the Hammett method combined with UV-visible spectroscopy.Then the catalytic activity of the ILs for the synthesis of methylene diphenyl dimethylcarbamate (MDC) from methyl phenyl carbamate (MPC) and formaldehyde (HCHO) was evaluated.The result showed that the acid strength of the ILs was well consistent with their catalytic activity.The acidity of ［HSO₃-bpy］CF₃SO₃ was the strongest and its catalytic activity was the highest.The reaction conditions for the synthesis of MDC were optimized using ［HSO₃-bpy］CF₃SO₃ as reaction media.Under the suitable reaction conditions of 70℃, 60 min, molar ratio of MPC to HCHO 12 and mass ratio of ILs to MPC 4, the yield of MDC was 91.5％.［HSO₃-bpy］CF₃SO₃ could be reused more than five times after the removal of water by vacuum distillation.