Thermodynamics Research Center / ThermoML | International Journal of Thermophysics

ABSTRACT

Osmotic coefficients, , electrical conductance data, ?, and refractive indices nD of aqueous solutions of ionic liquid, 1-pentyl-3-methylimidazolium chloride [PnMIm]Cl have been measured at T = (298.15, 308.15, 318.15, and 328.15) K. Measurements of osmotic coefficients were carried out by the vapor pressure osmometry method (VPO). Osmotic coefficient values show that ion-solvent interactions are stronger at low temperature. The osmotic coefficients were correlated to the Pitzer ion-interaction and modified NRTL (MNRTL) models. From these data, mean activity coefficients, +- and excess Gibbs free energies, GE have been calculated. Electrical conductance data have been applied for determination of association constants, Ka, limiting molar conductance, ?0, using low concentration Chemical model (lcCM).Calculated ion-association constant, Ka, values represent that ion-association effects increase at high temperatures which is in agreement with osmotic coefficient results. Experimental results of refractive indices for binary system are reported, and have been fitted by a polynomial expansion.