Physicochemical properties of aqueous solution of 1-methylimidazolium acetate ionic liquid at several temperatures

Densities ( ρ ) and viscosities ( η ) of 1-methylimidazolium acetate ([Mim]Ac) protic ionic liquid   +   water mixture were measured at T   =   (293.15, 298.15, 303.15, 308.15 and 313.15) K under atmospheric pressure. Refractive indices ( n D ) and electrical conductivities ( κ ) of the above-mentioned system over the entire composition range were measured at 298.15   K. Excess molar volumes ( V E ), viscosity deviations (Δ η ) and refractive index deviations (Δ n D ) were obtained from the experimental data and fitted to the Redlich–Kister equation with satisfactory results. The results show that V E values of the system are negative over the whole composition range, whereas Δ η and Δ n D values are positive. Other volumetric properties such as apparent molar volumes ( V ϕi ), partial molar volumes ( V ¯ m , i ) and excess partial molar volumes ( V ¯ m , i E ) of the system were calculated from the density data. The concentration dependence of κ was fitted according to the empirical Casteel–Amis equation. The measured and derived properties were employed to investigate the intermolecular interactions of the system.