The study of intermolecular interactions in [Bmim][PF6] + 1-octyl-2-pyrrolidone binary mixtures from volumetric, acoustic, optical and spectroscopic measurements

Abstract

Under 101.3 kPa pressure, the densities, speeds of sound, and refractive indices of [Bmim][PF6] + 1-octyl-2-pyrrolidone mixtures were determined experimentally over the whole composition range and at 303.15 to 323.15 K. The excess molar volumes (VmE), excess values of partial molar volumes (V¯mE), partial molar volumes at infinite dilution (V¯mE,∞), excess values of isentropic compressibility (KsE), speeds of sound (uE) and isobaric thermal expansion coefficient (αPE) have been calculated using these experimental data. The Redlich–Kister polynomial equation has been adequately fitted to the computed data. Intermolecular interactions between like and unlike molecules have been interpreted using the experimental and computed data. The Prigogine–Flory–Patterson theory of excess molar volume and IR spectroscopic studies supported the conclusions drawn from volumetric and acoustic properties.