Physical and excess properties of a room temperature ionic liquid (1-methyl-3-octylimidazolium tetrafluoroborate) with n-alkoxyethanols (C 1E m, m = 1 to 3) at T = (298.15 to 318.15) K

Abstract

Physical properties, such as densities, ρ, and refractive indices, n, for the binary mixtures of 1-methyl-3-octylimidazolium tetrafluoroborate [Omim][BF 4] with ethylene glycol monomethyl ether (EGMME; C 1E 1), diethylene glycol monomethyl ether (DEGMME; C 1E 2), and triethylene glycol monomethyl ether (TEGMME; C 1E 3) have been measured over the whole composition range. Experimental densities were used to estimate excess molar volumes, V m E , apparent molar volumes, V ϕ, i , partial molar volumes, V ¯ m, i , excess partial molar volumes, V ¯ m, i E , and their limiting values at infinite dilution, V ϕ , i ∞ , V ¯ m, i ∞ , and V ¯ m, i E, ∞ , respectively. Volumetric results have been analyzed in the light of Prigogine–Flory–Patterson (PFP) statistical mechanical theory. Deviations in refractive indices Δ ϕ n have been calculated from experimental measurements of refractive indices, n. Excess properties are fitted to the Redlich–Kister polynomial equation to obtain the binary coefficients and the standard errors. The results are compared with those of binary mixtures of 1-methyl-3-octylimidazolium tetrafluoroborate containing alcohols reported in the literature or the binary mixtures of 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF 6] with an alkoxyethanol reported in an earlier communication.