低熔点低粘度的季铵盐类离子液体的合成与表征

Synthesis and characterization of novel quaternary ammonium ionic liquids with low melting point and viscosity

烷基链的长短和对称性影响着四烷基季铵离子液体的理化性质,影响着其应用前景.本实验室设计、合成了系列新型丁基三乙基季铵型功能化离子液体,该类离子液体与之前报道的相应离子液体相比,具有相对较低的熔点,同时也具有更低的粘度.合成的离子液体中阴离子分别是三氟甲基磺酰根((CF3SO2)2N-)、六氟磷酸根(PF6-)、四氟硼酸根(BF4-)、硫酸氢根(HSO4-)、硫氰酸根(SCN-)和对甲苯磺酸根(PTSA-);利用核磁共振仪、密度仪、热分析仪、黏度仪、元素分析仪对其进行表征;研究了其与常规溶剂的相溶性,并对其结构和性质之间的关系进行探讨.

The length of the alkyl groups and the symmetry of the cations in tetraalkylammonium-based ionic liquids affect the physical properties and their applications. A novel class of ionic liquids based on triethylbutylammonium cation was prepared in our group. In this series, （ CF3SO2 ）2N E bis （trifluoromethanesufonyl）imide, PF6- , BF , HSO4 , SCN-and PTSA- （p-toluenesulfonic acid） were assigned to be the counter ions for the ionic liquids. The synthesis of ionic liquids started with the reaction of triethylamine and n-butyl bromide, followed by the ionic exchange using LiNTf2 , KPF6 , NH4BF4 , （Ag2O and H2SO4 ）, KSCN and （Ag2O and PTSA） as the reactants. Then the residue was extracted with diethyl ether for several times to get the pure product. -H NMR, thermal analysis, cone-plate viscometry, densitometer method, element analysis are applied to determine the structures and properties of these ionic liquids. It is found that these ILs have lower melting points and viscosities compared to the corresponding ionic liquids with symmetrical tetraalkyammonium cations,indicating the significant importance of the asymmetrical cation on the physical properties of the ILs. The miscibility of these ILs with some common solvents was studied, and the relationship between configuration and property of the ILs were also discussed.