Study on the Conductivities of Pure and Aqueous Bromide-Based Ionic Liquids at Different Temperatures

Electrical conductivities were measured for the pure ionic liquids [C6mim][Br] (1-hexyl-3-methylimidazolium bromide) and [C8mim][Br] (1-octyl-3-methylimidazolium bromide) at 0.1 MPa from 293.15 to 333.15 K. Conductivity measurements were also made for the binary water + [C6mim][Br] and water + [C8mim][Br] systems and their ternary water + [C6mim][Br] + [C8mim][Br] system at 0.1 MPa and 293.15, 298.15, and 303.15 K. The conductivity data of the pure ionic liquids were correlated by the VFT (Vogel-Tamman-Fulcher) equation, and the fitting parameters and mean absolute deviations were determined. New explanations are presented for the molality-dependent behavior of the conductivity of the binary water + [C6mim][Br] and water + [C8mim][Br] systems. The generalized Young’s rule and the semi-ideal solution theory for conductivity were used to predict the conductivities of the ternary water + [C6mim][Br] + [C8mim][Br] system from the conductivities of its corresponding binary water + [C6mim][Br] and water + [C8mim][Br] subsystems. The predictions are in good agreement with the measured values.