Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (11): 2663-2670.doi: 10.3866/PKU.WHXB201607292

• ARTICLE • Previous Articles     Next Articles

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

Ling ZHENG1,Yi PAN1,Hong-Xiang JI1,Xiao-Xue MA1,3,*(),Nan-Nan XING1,Wei GUAN1,2,*()   

  1. 1 College of Chemistry, Liaoning University, Shenyang 110036, P. R. China
    2 School of Environmental Science, Liaoning University, Shenyang 110036, P. R. China
    3 Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
  • Received:2016-06-14 Published:2016-11-08
  • Contact: Xiao-Xue MA,Wei GUAN E-mail:mxx_1985@163.com;guanweiy@sina.com
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21373104);The project was supported by the National Natural Science Foundation of China(21273003);Program for Liaoning Excellent Talents in University, China(LR2015025)

Abstract:

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 W values. Several experiments were conducted to evaluate the validity of this model. Eight different ILs, including five N-alkyl-pyridinium dicyanamide ILs[Cnpy] [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 W values 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.

Key words: Ionic liquid, Conductivity, Viscosity, Transition model, Walden product

MSC2000: 

  • O642