Salt concentration dependence of the compensated Arrhenius equation for alcohol-based electrolytes

It has been previously shown that the temperature-dependent conductivity of dilute, organic liquid electrolytes is non-Arrhenius due to the temperature dependence of the dielectric constant contained in the exponential prefactor. Scaling the temperature-dependent conductivities to conductivities at a reference temperature removes the dielectric constant dependence: the log of the scaled conductivities is then linearly dependent on the inverse temperature. Previous applications of this analysis focused on 0.0055 M solutions of tetrabutylammonium triflate (TbaTf) dissolved in linear alcohols and linear ketones. This work expands the scope of this analysis to a range of salt concentrations and different salts in propanol solutions. The energy of activation in TbaTf-propanol solutions obtained by the analysis described above varied in a smooth but nonlinear fashion from 32.6 +/- 0.3 kJ mol(-1) at 4.30 x 10(-5) M to 39.4 +/- 0.3 kJ mol(-1) at 5.50 x 10(-3) M. An examination of the temperature dependence of six salts in propanol suggests that choice of the cation has a larger effect on the activation energy than the choice of the anion. (C) 2009 Elsevier Ltd. All rights reserved.