Density and speed of sound measurements of imidazolium-based ionic liquids with acetonitrile at various temperatures

Abstract

In the present study, the interactions between acetonitrile and imidazolium-based ionic liquids (ILs) were discussed in terms of density (ρ) and speed of sound (u) measurements. The ILs used in this study were 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM]⁺[EtSO4]¯) and 1-butyl-3-methylimidazolium thiocyanate ([BMIM]+[SCN]−). The ρ and u of acetonitrile, ILs, and their binary systems {[EMIM]⁺[EtSO4]¯ or [BMIM]⁺[SCN]¯ (x₁) + acetonitrile (x₂)} were measured at 293.15, 298.15, 303.15, 308.15 and 313.15 K and at p = 0.1 MPa. The derived properties such as excess molar volumes, VmE, isentropic compressibility, κs, and deviation in isentropic compressibility, Δκs, were calculated from experimental density and speed of sound data, respectively. The Redlich–Kister polynomial equation was used to fit the excess/deviation properties. These results are useful for describing the intermolecular interactions, developing structure–property correlation and molecular modeling that exist between the acetonitrile and imidazolium-based IL mixtures.