长链多磺酸基官能化杂多酸离子液体催化的苯甲醇无溶剂H2O2选择性氧化研究

Selective Oxidation of Benzyl Alcohol with H2O2 Catalyzed by long ChainMulti -SO3H Functionalized Heteropolyanion-based Ionic Liquids underSolvent-free Conditions

摘要:

以十二烷基二甲基叔胺、1, 3-丙烷磺内酯、磷钨酸、硅钨酸为起始原料经季铵化、酸化两步原子经济反应，合成了两种室温下为液相的多磺酸基官能化杂多酸离子液S4ILs 和S3ILs。 目标离子液体的结构经红外光谱、核磁共振波谱得到确认。S4ILs 、S3ILs为均相催化剂、35%（质量分数）H2O2为氧化剂，在无溶剂条件下实现了系列苯甲醇的选择性氧化，当n(离子液体)：n(醇): n (过氧化氢)=0.05:30:45，反应温度70℃，反应时间4h时，S4ILs将苯甲醇氧化为对应的苯甲醛，产率81-100%，S3ILs则将苯甲醇一步氧化为对应的苯甲酸，产率64-94%。离子液体经除水、乙醚洗涤、真空干燥即可循环使用，循环使用5次催化活性保持不变。

Abstract:

Two novel long chain multi SO3H-functionlized heteropolyanion-based ionic liquids S4ILs 、S3ILs were synthesized by using aliphatic polyamines, 1,3-propane sultone and Keggin type heteropolyacid as the sources chemicals via quaternarization and acidification two step reaction. Their structures were confirmed by FT-IR, 1H NMP. Two ionic liquids acted as homogeneous catalysts for selective oxidation of benzyl alcohol using 35% H2O2 as oxidant under solvent-free conditions was studied. When the mole ratio of ionic liquids/alcohol/H2O2 =0.05:30:45,the reaction could completed at 70℃ within 4 hour, for S4ILs the corresponding benzaldehydes were obtained in the yields of 81% to 100%. But for S3ILs the corresponding benzoic acids were obtained with yields of 64% to 94%. Two ionic liquids could be easily recovered after removal of water, washed with diethyl ether and drying under vacuum and reused five times without loss in their catalytic activity.