直链多磺酸基官能化Keggin型杂多酸离子杂化体催化的环己酮无溶剂氧化研究

Oxidation of Cyclohexanone Catalyzed by Straight Chain Multi -SO3H Functionalized Keggin-type Heteropolyacid Ionic Hybrids under

摘要:

研究以脂肪多胺、1, 4-丁烷磺内酯、磷钨酸、硅钨酸为起始原料，经季铵化、酸化二步反应，合成了二种直链多磺酸基官能团Keggin型杂多酸离子杂化体HPAILs-1-2，目标杂化体的结构经红外光谱、核磁共振、XRD等得到确认。以HPAILs-1-2为非均相催化剂、工业级35%H2O2为氧化剂，在无溶剂反应条件下探索了环己酮的Baeyer-Villiger氧化，结果表明，当HPAILs-1-2/环己酮/过氧化氢=0.05:1:2.5（摩尔比），反应温度50℃时，反应在3h完成，ε-己内酯产率分别为75%、70%。HPAILs-1-2经过滤、水洗、乙醚洗涤、真空干燥后可循环使用，循环使用5次催化活性基本保持不变。

Abstract:

Two straight chain multi SO3H-functionlized Keggin-type heteropolyacid ionic hybrids (HPAILs-1-2) were synthesized by using aliphatic polyamines, 1,4-butane-sultone and Keggin type heteropolyacid as the sources chemicals via quaternarization and acidification two step reaction。Their structure were confirmed by FT-IR,1H NMP and XRD.HPAILs-1-2 acted as heterogeneous catalysts for oxidation of cyclohexanones using 35% H2O2 as oxidant under solvent-free conditions was studied. Upon the optimized conditions，when the mole ratio of HPAILs-1-2/cyclohexanone/H2O2 =0.05:1:2.5,the reaction could completed at 50℃ within 3 hour and gave ε-caprolactone in the isolated yields of 75% and 70%. HPAILs-1-2 could be easily recovered after filtration, washed with water, diethyl ether and drying under vacuum and reused five times without significant loss in their catalytic activity.