Temperature and pressure dependence of the electrical conductivity of two tetraalkylammonium tetraalkylborate salts

Electrical conductivities of molten trimethylpentylammonium triethyloctylbo rate (N1115B2228) and triethylpentylammonium triethylpentylborate (N2225B22 25) 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 equ ation, k = A exp[ - B/(T - T-o)]. The empirical nature of the pressure depe ndence of the B and T-o parameters has revealed the possibility of obtainin g an isothermal equation to explain the pressure dependence of the electric al conductivity. Accordingly, an empirical equation of the form k = a'exp(b 'P+c'P-2) has been found to describe the pressure dependence of the electri cal conductivity. The ideal glass transition temperature, T-o, is the key p arameter in controlling the pressure dependence of the electrical conductiv ity for both systems under study.