Conductivity and ionic association of tetraalkylammonium halides in tert-butanol–water mixture at 25 °C

Abstract

The molar conductivities of Pr4NBr, Bu4NBr, Pr4NI, and BU4NI have been measured in tert-butanol–water (t-BuOH–H2O) mixtures (61.30 ≥ D ≥ 16.50) over the maximum concentration range (2 × D3 × 10−7 mol dm−3) along with the densities and viscosities of the solvent mixtures at 25 °C. The conductance data have been analysed by using the Fuoss-1978 (F78) conductance equation and the results compared with the values obtained from the Justice (J), Pitt's (P), and Fuoss–Onsager–Skinner (FOS) equations. Molar conductivities at infinite dilution (Λ0), the thermodynamic ion association constants (KA) and the distance or ion-size parameters (R0 or a0) are evaluated from these data. The F78 equation fitted the data better and yielded KA and R values which are in accord with the ion-association theories. The interpretation of these parameters is discussed to provide some insight on the magnitude of the ionic association and the ion–solvent interaction.