The study of solute–solvent interactions in 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate + acetonitrile from solvent activity, density, speed of sound, viscosity, electrical conductivity and refractive index measurements

Abstract

The solute–solvent interactions that occurred between the ionic liquid of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate and acetonitrile have been studied. For this purpose, the vapor–liquid equilibrium data (solvent activity, osmotic coefficient and vapor pressure) were determined for 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate in acetonitrile by the isopiestic method at 298.15K. Experimental osmotic coefficients are reliably correlated by Pitzer and Archer extension of Pitzer models. These models were also used to calculate the vapor pressure values. Density, speed of sound, viscosity, electrical conductivity and refractive index values were also measured for this binary system at T=288.15, 293.15 and 298.15K. Density and speed of sound values have been used to calculate the apparent molar volumes and apparent molar isentropic compression. The corresponding limiting apparent molar quantities were found by extrapolation to infinite dilution with using Redlich–Meyer equation. Viscosity B-coefficients were obtained from Jones–Dole equation. Low concentration Chemical Model (lcCM) of conductance equation in terms of ion association constant and limiting molar conductivity was used to analyze the electrical conductivity data. The standard Gibbs energy for the ion-association process was also calculated. Lorentz–Lorenz equation was used to calculate the values of molar refraction.