基于离子交换跃迁模型和实验法对离子液体Walden乘积的研究

Evaluation of the Walden Product of Ionic Liquids Using Experiments and a New Theory:An Ion Exchange Transition Model

提出了关于离子液体的新理论——离子交换跃迁模型,通过理论推导得出1:1型离子液体的Walden乘积仅取决于离子对和离子簇直径的统计平均值,即离子液体的阴阳离子结构不同,Walden乘积不同。为了验证模型的正确性,本文合成8种N-烷基-吡啶二氰胺类和N-烷基-咪唑丝氨酸类离子液体,利用上述离子液体的电导率和动力粘度的实验值及文献数据,计算了33种离子液体的Walden乘积。通过比较发现,不同离子液体的Walden乘积不同,即对于离子液体来说,Walden乘积是它的特征物理量。

A new theory has been developed to evaluate the Walden product, W, of ionic liquids using an ion exchange transition model. This model showed that the product （Walden） of molar conductivity and dynamic viscosity is related to the average diameters of the ion pairs and ion clusters of ionic liquids （ILs） with 1 ： 1 charge ratios, namely, different ILs have different Wvalues. Several experiments were conducted to evaluate the validity of this model. Eight different ILs, including five N-alkyl-pyridinium dicyanamide ILs [C,py][DCA] （n = 2-6） and three N-alkyl-3-methyllimidazolium serine ILs [Cnmim][Ser] （n = 2-4） were successfully synthesized and evaluated in terms of their conductivity and dynamic viscosity properties. The Wvalues of 33 different ILs were calculated based on their experimentally determined molar conductivity and dynamic viscosity values, and the results revealed that these values were consistent with those of the ion exchange transition model. Taken together, these results demonstrate that W is a key physical parameter for ILs.