碱性离子液体催化合成碳酸二丙酯

以碱性离子液体催化正丙醇(n-PrOH)与碳酸二甲酯(DMC)进行酯交换反应合成碳酸二丙酯(DPC),筛选出催化性能和稳定性较好的碱性离子液体1-丁基-3-甲基咪唑咪唑盐(bmIm]Im)作为催化剂,并对该催化剂催化n-PrOH与DMC酯交换反应的条件进行了优化。实验结果表明,bmIm]Im对n-PrOH与DMC酯交换合成DPC反应具有较高的催化活性,在反应时间4 h(90℃1 h,95℃3 h)、催化剂用量(基于总反应物的质量分数)2.0%、n(DMC)∶n(n-PrOH)=1∶4的条件下,DPC的收率可达50.6%。bmIm]Im重复使用5次后,DPC的收率仍达47.4%,稳定性良好。通过GC-MS,FTIR,1H NMR分析,确认所合成的产物为DPC;并对反应机理进行了探讨。

Synthesis of Dipropyl Carbonate Catalyzed by Alkaline Ionic Liquid

The synthesis of dipropyl carbonate(DPC) through transesterification of dimethyl carbonate(DMC) and propyl alcohol(n-PrOH) with alkaline ionic liquids as the catalysts was studied,in which alkaline ionic liquid 1-butyl-3-methylimidazolium cation and imidazolide anion(Im) was selected due to its good catalytic performance and stability compared with the other two alkaline ionic liquids.The transesterification reaction conditions were optimized.The results showed that under reaction time 4 h(90 ℃ for 1 h and then 95 ℃ for 3 h),catalyst dosage(based on the total mass of the reactants) 2.0% and n(DMC) ∶ n(n-PrOH) 1 ∶ 4,DPC yield was 50.6%.After alkaline ionic liquid Im was reused 5 times,the DPC yield still reached 47.4%.The product was confirmed by means of GC-MS,FTIR and 1H NMR,and the reaction mechanism was discussed.