An experimental investigation of molecular interactions between [Emim][triflate] ionic liquid & 2-alkoxyethanols and theoretical comparison by PFP theory

Physical properties, such as density (rho) and speed of sound (u) of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 2-ethoxyethanol/2-propoxyethanol and their binary mixtures are measured over the whole composition range as a function of temperature between 298.15 K and 318.15 K at atmospheric pressure. Experimental values were used to calculate the excess molar volumes (V-m(E)), excess values of partial molar volumes (V-m(E)), excess values of isentropic compressibility (kappa(E)(S)), free length (L-f(E)), speeds of sound (u(E)) and isobaric thermal expansion coefficient (alpha(E)(P)) for the binary mixtures. These excess properties were fitted to the Redlich-Kister type equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates the interaction decreases with the increase in chain length. This was further supported by Prigogine-Flory-Patterson (PFP) theory of excess molar volume. (C) 2019 Elsevier Ltd.