Physicochemical properties of dilute aqueous solutions of 1-Ethyl-3-Methylimidazolium Ethylsulfate, 1-Ethyl-3-Methylimidazolium Methylsulfate, 1-Ethyl-3-Methylimidazolium Tosylate and 1, 3-Dimethylimidazolium Methylsulfate at different temperatures and at atmospheric pressure

Abstract

This work presents the experimental data on thermophysical properties of aqueous solutions of imidazolium-based ionic liquids (ILs) such as 1-Ethyl-3-Methylimidazolium Ethylsulfate [EMIM][EtSO4], 1-Ethyl-3-Methylimidazolium Methylsulfate [EMIM][MeSO4], 1-Ethyl-3-Methylimidazolium Tosylate [EMIM][Tos], and 1,3-Dimethylimidazolium Methylsulfate [MMIM][MeSO4] in water at different temperatures. Many researchers have studied imidazolium based ILs in different solvents but there is scarcity of data in dilute region. So the aim of this work is to understand the interactions between imidazolium based ILs and water in dilute region. To understand the ion-ion and ion–solvent interactions between IL and water, the thermophysical properties such as density (ρ), speed of sound (u), and viscosity (η) have been measured at temperatures T = (298.15, 303.15, 308.15 and 313.15) K and at atmospheric pressure. The properties like apparent molar volume, limiting apparent molar volume and coefficient of thermal expansion have been derived from the density data. The speeds of sound and density data were combined to evaluate isentropic and isothermal compressibilities. Using Jones-Dole equation, the viscosity A and B coefficients have been determined. The influence of IL cation chain length, different anions and temperature on the sign, magnitude of BV (the deviation parameter from Debye-Hückel theory) and on viscosity B-coefficient has been discussed.