3种氯铝酸离子液体的密度、黏度和电导率的研究

The density,viscosity and electrical conductivity of three chloroaluminate-based ionic liquids

合成了3种典型的氯铝酸离子液体,通过高精度振动管密度计、自动落球式微量黏度计、电导率仪对体系的密度、黏度和电导率进行了系统测定.所有实验值与经验公式吻合,并获得了相应的拟合参数.在此基础上,采用理论计算方法进一步研究了离子液体的构效关系.结果证明,氯铝酸离子液体具有较大的密度、较低的黏度和较高的电导率.阳离子上碳链的增长降低了分子的对称性,不利于离子的紧密堆积,从而使密度减小.另一方面,当阴阳离子间相互作用和氢键增强时,离子液体的黏度随之升高,电导率降低.

Three typical chloroaluminate-based ionic liquids were synthesized.The density,viscosity and electrical conductivity of these ionic liquids were measured by high-precision vibrating tube densimeter,automated falling ball microviscometer and conductivity meter,respectively.All the experimental data have been well fitted by the empirical equations.The corresponding adjustable parameters were also obtained.On this basis,theoretical calculations were carried out to investigate the structure-activity relationship of these ionic liquids.On the one hand it showed that chloroaluminate-based ionic liquids had higher density,lower viscosity and higher electrical conductivity than many other ionic liquids.The increasing length of alkyl chain on the cation reduced molecular symmetry,which was unfavorable to the close packing of ions.In this case,the density of ionic liquids decreased.On the other hand,the increasing viscosity reduced electrical conductivity of ionic liquids when the cation-anion interaction energy and hydrogen bonding was enhanced.