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

Abstract

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 (nD) and electrical conductivities (κ) of the above-mentioned system over the entire composition range were measured at 298.15K. Excess molar volumes (VE), viscosity deviations (Δη) and refractive index deviations (ΔnD) were obtained from the experimental data and fitted to the Redlich–Kister equation with satisfactory results. The results show that VE values of the system are negative over the whole composition range, whereas Δη and ΔnD values are positive. Other volumetric properties such as apparent molar volumes (Vϕi), partial molar volumes (V¯m,i) and excess partial molar volumes (V¯m,iE) 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.