Conductivity studies of tetrabutylammonium salts in 1-propoxy-2-propanol: Ion-association in dilute solutions

Abstract

The molar conductivities ? of n-tetrabutylammonium bromide, n-tetrabutylammonium nitrate, n-tetrabutylammonium thiocyanate and n-tetrabutylammonium acetate solutions in 1-propoxy-2-propanol (PnP) have been measured. The temperature and concentration range covered is from 248.15 to 313.15 K and 0.18 × 10-3 to 6.4 × 10-3 mol L-1, respectively. Accurate viscosity, density and permittivity data were additionally determined for the pure solvent. Data analysis was performed on the basis of the low concentration Chemical Model (lcCM), including short-range forces. Values for the limiting molar conductivities (A∞) and the association constants KA are derived. Thermodynamic results on the ion-pair formation process are discussed in terms of coulombic and non-coulombic forces by an appropriate splitting of the Gibbs free energy.