The study of solute–solvent interactions in 1-ethyl-3-methylimidazolium ethylsulfate + 2-ethoxyethanol from density, speed of sound and refractive index measurements

Abstract

Physical properties, such as density (ρ), speed of sound (u) and refractive index (nD) for pure [Emim][EtSO4], 2-ethoxyethanol and their binary mixtures are measured using Anton Paar vibrating tube density, sound velocity meter (DSA 5000M) and automatic refract meter over the whole composition range as a function of temperature between (298.15–328.15)K at atmospheric pressure. Experimental values were used to calculate the excess molar volumes (VmE), excess values of partial molar volumes (V̅mE), partial molar volumes at infinite dilution (V̅mE,∞), excess/deviation values of isentropic compressibility (κsE), isothermal compressibility (κTE), free length (LfE), speed of sound (uE), refractive index (ΔϕnD), internal pressure (πiE), free volume (VfE) and isobaric thermal expansion coefficient (αPE) for the binary mixtures. These excess/deviation properties were fitted to the Redlich–Kister type equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates strong intermolecular interactions between the liquids in study. This was further supported by IR spectroscopy.