Temperature and Pressure Dependence of the Electrical Conductivity of Two Tetraalkylammonium Tetraalkylborate Salts

Abstract

Electrical conductivities of molten trimethylpentylammonium triethyloctylborate (N1115B2228) and triethylpentylammonium triethylpentylborate (N2225B2225) were measured as functions of temperature (c. 293 · 15–383 · 15 K) and pressure (from 1 bar to 5 kbar). Analysis of the temperature dependence of the electrical conductivity was made by using the Vogel–Tammann–Fulcher equation, &kgr; = Aexp[ – B/(T – T₀)]. The empirical nature of the pressure dependence of the B and T₀ parameters has revealed the possibility of obtaining an isothermal equation to explain the pressure dependence of the electrical conductivity. Accordingly, an empirical equation of the form &kgr; = a′exp(b′ P+c′ P²) has been found to describe the pressure dependence of the electrical conductivity. The ideal glass transition temperature, T₀, is the key parameter in controlling the pressure dependence of the electrical conductivity for both systems under study.