微波加热下功能化离子液体催化合成辛酸苄酯

Synthesis of Benzyl Octanoate Catalyzed by Task-specific Ionic Liquids under Microwave Irradiation

目的:研究传统和微波加热下,以具有丙烷磺酸基功能基团的离子液体作催化剂催化苯甲醇和正辛酸合成辛酸苄酯,其阴、阳离子对催化剂活性的影响。催化剂用量、反应时间和微波功率等对酯化率的影响以及催化剂稳定性。方法:用NaOH-乙醇(0.1 mol/L)标准溶液滴定,通过酸值测定确定其酯化率。结果:[PSPy]HSO4、[TMAPS]HSO4作催化剂,固定7.5 mmol苯甲醇,5mmol正辛酸,催化剂量为正辛酸的20 mol%,反应温度为120℃,反应时间为20 min,功率为375W,酯化率分别为94.9%、93.5%。[TMAPS]HSO4催化剂重复使用10次后活性没有明显降低,酯化率仍有88.5%。结论:微波加热和传统加热,功能化离子液体的阴、阳离子对酯化率的影响规律相似,但微波加热显著地缩短了反应时间,具有潜在的应用价值。催化剂具有良好的稳定性。

Objective： A series of task- specific ionic liquids （TSILs） that bear an alkane sulfonic acid group were synthesized. Esterification yield of octylic acid with benzyl alcohol was investigated using these TSILs as catatlystys in both microwave irradiation and traditional heating ways. Effect of the anion and cation of the TSILs, catalyst amount, reaction time, microwave power on esterification yield, catalyst stability were systematically investigated. Method： The esterification yield determined by acid value which was titrated by NaOH-ethanol （0. 1 mol/L） standard solution. Result： Esterification yield reached 94. 9% and 93.5%, respectively, by using [ TMAPS ] HSO4 and [ PSPy ] HSO4 as the catalyst under the conditions of 5 mmol octylic acid, 7.5 mmol benzyl alcohol, molar fraction is 20% of octylie acid for TSILs, 120℃, 20 min and 375 W. [ TMAPS ] HSO4 could be reused ten times without considerable loss of activity and still had a conversion of 88.5%. Conclusion： Effect of the anion and cation of the TSILs on the esterification under microwave irradiation is similar to those traditional heating way. Compared with traditional heating way, TSILs exhibited a enhanced reaction efficiency and significantly short reaction time under microwave irradiation. The [ TMAPS ] HSO4 and [ PSPy] HSO4 which have potential value of application exhibited excellent stability and catalytic activity.