Activity coefficients at infinite dilution measurements for organic solutes and water in the 1-hexyloxymethyl-3-methyl-imidazolium and 1,3-dihexyloxymethyl-imidazolium bis(trifluoromethylsulfonyl)-imide ionic liquids—The cation influence

The activity coefficients at infinite dilution, γ 13 ∞ for 35 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, acetone and water in the ionic liquids 1-hexyloxymethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)-imide [C6H13OCH2MIM][NTf2] and 1,3-dihexyloxymethyl-imidazolium bis(trifluoromethylsulfonyl)-imide [(C6H13OCH2)2IM][NTf2] were determined by gas–liquid chromatography over a wide range of temperature from (298.15–368.15) K. The values of the partial molar excess enthalpies at infinite dilution, Δ H 1 E , ∞ , were calculated from the experimental γ 13 ∞ values obtained in the temperature range investigated. The selectivity for the separation of n-hexane/benzene, cyclohexane/benzene, n-hexane/thiophene, hex-1-ene/n-hexane and hex-1-ene/benzene by the extractive distillation or solvent extraction processes were calculated from the γ 13 ∞ values and were compared to the literature values for other ionic liquids, and popular entrainers as NMP and sulfolane at temperature T = 298.15 K.