Thermophysical, excess and transport properties of organic solvents with imidazolium based ionic liquids

Ultrasonic velocity and refractive index have been evaluated for eight binary mixtures comprising imidazolium based ([BMIM][PF6], [HMIM][PF6], [OMIM][PF6] and [MMIM][CH3SO4]) ionic liquids with three organic solvents of varying nature, viz., 2-propanol, 2-butanone and ethylacetate, at three different temperatures (293.15, 298.15 and 303.15 K). Evaluation of refractive index has been carried out by eight approaches, whereas five methods have been employed for computation of ultrasonic velocity. Molecular interaction studies have been carried out with the help of intermolecular free length, and interaction parameter. Furthermore, the excess counterpart of the coefficient of thermal expansion has been determined to get a deeper understanding on the behavior in terms of nature and extent of interactions present in these systems.