Evidence of a Critical Anomaly of the Electrical Conductivity in Highly Concentrated Nonaqueous Ionic Mixtures

Abstract

We present the first electrical conductivity measurements performed in highly concentrated electrolyte solutions near a critical consolute point. The critical binary mixtures studied are tetra-n-butylammonium picrate in 1-dodecanol and 1,4-butanediol solvents. An accurate determination of the regular conductivity in the one-phase region indicates the presence of a critical anomaly in the electrical conductivity for $\ensuremath{\tau}<{10}^{\ensuremath{-}2}$, where \ensuremath{\tau} is the reduced temperature. The nature of the anomaly does not correlate with the values of the viscosity, the dielectric constant, or the free ion concentration of the mixtures.