Thermophysical properties of dimethylsulfoxide with ionic liquids at various temperatures

Abstract

In this article, we present densities ( ρ), ultrasonic sound velocities ( u) and viscosities ( η) for the binary systems of the highly polar compound dimethylsulfoxide (DMSO) with ionic liquids (ILs) over the whole composition range at temperature ranging from 298.15 to 328.15 K under atmospheric pressure. The ILs investigated in the present study included diethyl ammonium hydrogen sulfate ([Et 2NH][HSO 4], DEAS) is an ammonium salt (protic IL) and 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) is an imidazolium salt (aprotic IL). Further, to gain some insight into the several aggregations of molecular interactions present in these mixed solvents, we predicted the excess molar volume ( V E), the deviation in isentropic compressibilities (Δ K s ) and deviation in viscosity (Δ η) as a function of the concentration of IL using the measured properties of ρ, u and η, respectively. Redlich–Kister polynomial was used to correlate the results. The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. A qualitative analysis of the results is discussed in terms of the ion–dipole, ion-pair interactions, and hydrogen bonding between ILs and DMSO molecules and their structural factors. Comparison of these properties of DMSO with ILs explicitly elucidates the influence of ions and also the temperature effects on the thermophysical properties.