Conductance of lithium and sodium perchlorates and tetraphenylborates in 2-butanone from -35 to 25°C

Abstract

Conductances of dilute solutions of LiClO4, NaClO4, LiBPh4 and NaBPh4 in 2-butanone were measured at seven temperatures from −35 to 25°C. The limiting molar conductivities and association constants were evaluated using the conductance equation of Fuoss and Justice (including the Chen effect). The distance parameter was fixed at the Bjerrum distance. The limiting ionic conductivities, determined by assuming equal ionic conductivities of the i-Am3 BuN+ and BPh 4 − ions at all temperatures, were related to the crystallographic ionic radii using the Hubbard–Onsager model of dielectric friction corrected for the inhomogeneity of the electric field. The activation enthalpy of ionic transport in 2-butanone is almost independent of the nature of the electrolyte. The Walden products do not vary with the temperature. The correction to the conductance parameters for dielectric saturation computed for M+ClO 4 − associates was found to be small. Thermodynamic functions characterizing the association process were evaluated from K A data and their dependences on the temperature. The short-range, noncoulombic contributions to the Gibbs energy were estimated using Bjerrum's theory.