Conductometric and Refractometric Studies of 1-Propyl-3-methylimidazolium Bromide Ionic Liquid in Water + Ethylene Carbonate Mixtures at T = (298.2, 308.2 and 318.2) K

Abstract

In this work, we determined thermophysical properties such as electrical conductivity and refractive index for 1-propyl-3-methylimidazolium bromide, [PrMIm]Br in ternary mixtures of [PrMIm]Br + ethylene carbonate + water at T = (298.2, 308.2 and 318.2) K and 0.1MPa. Conductometric measurements were carried out for [PrMIm]Br ionic liquid in ethylene carbonate + water solvent mixture in various composition 10, 20 and 30 mass% of ethylene carbonate (EC) in the ionic strength ranging from 0.0029 to 0.2500 mol.kg-1. These data were treated by Fuoss-Onsager equation, and the values of limiting molar conductivity ( ) and ion association constant (KA) were obtained. These results used to calculate the Walden product ( ) and the corresponding standard thermodynamic functions of ion association process including Gibbs free energy ( ), enthalpy ( ) and entropy ( ) for the investigated system. In addition, refractive indices were measured for the binary and ternary [PrMIm]Br + water + EC mixtures at T = (298.2, 308.2 and 318.2) K. The refractive index deviations (ΔnD) were calculated and the binary and ternary data of ΔnD were correlated using Redlich-Kister and the Cibulka equations, respectively. Also, the measured refractive indices were compared to the calculated values using some mixing rules.