缬氨酸阳离子型离子液体的实验与理论研究

摘要

Six new amino acid ionic liquids(ILs) derived from valine(Val) were studied using both experimental and theoretical methods. First, the Val fluoborate (ValBF4 ), Val hydrochloride (ValCl), Val nitrate ( ValNO3 ), paratoluenesulfonic acid Val salt ( ValTsO ), Val sulfate ( Val2SO4 ), and Val phosphate ( Val3 PO4 ) were synthesized with one-step microwave synthesis method, and their physicochemical properties,including the IR spectra, melting points, thermostability and optical rotation were studied experimentally. It was found that ValBF4 and ValPO4 have potential in further application for their low melting points (less than 100 ℃ ). Using the combination of n-heptane and thiophene as model gasoline, the physical desulfurization effect of ValNO3 was investigated. Quantum chemistry calculations were also performed and the theoretical results were used as the supplementation or explanation for experimental study. Geometry optimizations on the single molecules of the Val complexes in gas phase were performed with DFT B3LYP/6-311 + + G* method,and the vibration frequencies of each optimized molecule were analyzed at the same level method. The binding energies between ions were calculated and the natural bond analysis was also performed. It was found that the combination of experimental and theoretical methods can help us to explore such kind of system more deeply and can provide some new idea for further design of amino acid ionic liquids.%以缬氨酸(Val),氟硼酸、对甲苯磺酸、硝酸、盐酸、硫酸和磷酸为原料,采用一步法在微波反应仪中合成缬氨酸阳离子型离子液体,得到了缬氨酸氟硼酸盐(ValBF4)、缬氨酸盐酸盐(ValCl)、缬氨酸硝酸盐(ValNO3)、缬氨酸对甲苯磺酸盐(ValTsO)、缬氨酸硫酸盐(Val2SO4)和缬氨酸磷酸盐(Val3PO4)共6种产物,并对其理化性质进行了表征.其中ValBF4和Val3PO4具有较低的熔点(低于100 ℃),但热稳定性较传统的离子液体差.此外,研究了缬氨酸阳离子型离子液体在汽油脱硫中的应用,以正庚烷作溶剂、噻吩作含硫杂质组成模拟汽油体系,将缬氨酸硝酸盐作为脱硫剂加入模拟油中,在超声波振荡后利用色谱仪检测不同振荡时间的脱硫效果.同时采用量子化学方法对合成的6种化合物的单个分子进行了理论研究,在B3LYP/6-311++G**水平下获得了最稳能量构型,并在此基础上进行了红外光谱、离子间相互作用及自然键轨道分析,从理论上对上述实验结果进行了解释.