The Residual Volume Approach II: Simple Prediction of Ionic Conductivity of Ionic Liquids

Abstract

The Residual Volume Approach (RVA), a recently developed method for the prediction of fundamental physical properties of ionic liquids (ILs) is extended and now allows the estimation of ionic conductivity of unknown ILs, using a simple linear correlation between the ionic conductivity and previously defined substituent parameters - βx. The proposed method is applied to the conductivity correlations of 61 n-alkyl substituted imidazolium, tetraalkylammonium, pyrrolidinium, piperidinium, sulfonium and phosphonium homologous ILs, containing [BF4]−, [Tf2 N]−, [C2 F5PF]−, [CF3BF3]−, [C2H5BF3]−, [F(HF)2.3]−, [Br]−, [I]−, and [formate]− as anions. The influence of the ion type - both anion and cation - on the property changes is discussed. Moreover, it is shown that relatively rigid cations with C2 symmetry decrease the expected conductivity in the same manner as they increase the viscosity of the ILs.