季铵盐离子液体的合成及表征

Synthesis and Characterization of Quaternary Ammonium-based Ionic Liquids

摘要:

以三乙胺和苄氯为原料，通过中间体氯化苄基三乙胺盐([Nbz222]Cl) 的阴离子交换反应合成了五种目标产物：苄基三乙胺四氟硼酸盐([Nbz222]BF4)，苄基三乙胺六氟磷酸盐([Nbz222]PF6)，苄基三乙胺硫酸氢盐([Nbz222]HSO4)，苄基三乙胺磷酸二氢盐([Nbz222]H2PO4) 和苄基三乙胺咪唑盐([Nbz222]Im)，产物的结构通过FT-IR，1H NMR，13C NMR，ESI-MS, 元素分析得以确认。除[Nbz222]PF6之外，其余四种目标产物的熔点均低于100℃。热分析表明目标离子液体的热稳定性顺序为： [Nbz222]HSO4 > [Nbz222]BF4 > [Nbz222]Im > [Nbz222]H2PO4，其中[Nbz222]HSO4具有较好的热稳定性，热分解温度在260℃左右。目标离子液体均有一定的吸水性并在极性溶剂中有较好的溶解性。

Abstract:

The objective compounds, benzyltriethylammonium tetrafluoroborate([Nbz222]BF4), benzyltriethylammonium hexafluorophosphate([Nbz222]PF6), benzyltriethyl-ammonium hydrogen sulphate([Nbz222]HSO4), benzyltriethylammonium dihydrogen phosphate ([Nbz222]H2PO4), and benzyltriethylammonium imidazolideintermediate([Nbz222]Im) were designed and synthesized by anion exchange reaction of the intermediate benzyltriethylammonium chloride which was prepared using triethylamine and benzyl chloride as starting materials. All the compounds including the quaternary ammonium-type ionic liquids(ILs) were characterized by FT-IR, 1H NMR, 13C NMR, ESI-MS and element analysis respectively. Meanwhile, the physical properties of the ILs were investigated. It was found that the melting points of the ILs are below 100℃ except for [Nbz222]PF6. The TG results indicated that the thermostability of [Nbz222]HSO4 is higher than the others associated with the decomposition temperature decrease in the orders of [Nbz222]HSO4 > [Nbz222]BF4 > [Nbz222]Im > [Nbz222]H2PO4. In addition, the ILs exhibited water absorption and were miscible well with polar solvent.