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 ioni 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]-., [Tf2N] -., [C2F5PF]-., [CF 3BF3]-., [C2H5BF 3]-., [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 C 2 symmetry decrease the expected conductivity in the same manner as they increase the viscosity of the ILs. © 2009 Verlag der Zeitschrift für Naturforschung, Tübingen.