Temperature and composition dependence of the volumetric and acoustic properties of ionic liquid [emim][HSO4] with polar protic and aprotic co-solvents

In the present paper, we report new experimental data on density (p) and speed of sound (u) in binary liquid mixtures of 1-ethyl-3-methylimidazolium hydrogen sulphate, [emim][HSO4] with polar protic solvents ethanol (EtOH) and 1-propanol (n-PrOH) and aprotic solvent, dimethyl sulphoxide (DMSO) over the complete range of mole fraction at 298.15 K <= T <= 313.15 K, every 5 K, and 0.1 MPa pressure. The mixing behaviour of the binary systems of [emim][HSO4] with EtOH, n-PrOH, and DMSO has been studied by computing the excess volumes (V-E) and excess isentropic compressibilities (kappa(E)(s)) utilizing the measured densities (p) and speeds of sound (u). Further, the excess functions V-E and kappa(E)(s) are correlated with mole fraction, using Redlich-Kister equation to derive the fitting parameters. For the systems studied, the excess thermodynamic properties (V-E and kappa(E)(s)) are found to be negative over the whole range of composition at investigated temperatures. Also, the experimental results are discussed in terms of ion-ion, iondipole, hydrogen bonding interactions and interstitial accommodation between component molecules in the binary liquid mixtures. Moreover, the temperature dependence of the physicochemical and excess properties has been studied. (C) 2018 Elsevier Ltd.