The molar conductivity of some molten alkyl4NBF4 salts as a function of temperature

Abstract

The conductivities and densities of molten (n-pentyl)4NBF4, (n-hexyl)4NBF4, (n-heptyl)4NBF4 and (n-octyl)4NBF4 have been studied over a temperature range of 120°C at atmospheric pressure. The molar conductivity results are fitted both to a polynomial and to a f(1/(T-T o)) from which empirical activation energies are evaluated. The non-Arrhenius behaviour is discussed in terms of the free volume theory of Cohen and Turnbull and the theory of Adam and Gibbs. These two theories account for the observed temperature dependence of molar conductivity and empirical activation energy in these molten organic salts. The effect of large and increasing cationic radius with constant anionic radius is discussed.