[Determination of thermodynamic parameters for ionic liquid 1-hexyl-3-methylimidazolium trifluoromethansulfonate by inverse gas chromatography].

The thermodynamic parameters of ionic liquid 1-hexyl-3-methylimidazolium trifluoromethansulfonate ([HMIM] OTF) were investigated by inverse gas chromatography in the temperature range of 343.15-373.15 K. Eighteen probe solvents were used to calculate the molar enthalpy of sorption, molar enthalpy of mixing at infinite dilution, molar enthalpy of vaporization and the mass fraction activity coefficients. Furthermore, Flory-Huggins interaction parameters, the solubility parameter of the ionic liquid were calculated to judge the interactions between [HMIM] OTF and the 18 probes solvents. The results showed that among the selected solvents, n-C6-9, tetrahydrofuran, diethyl ether, cyclohexane and benzene are the poor solvents for [HMIM] OTF, while dichloromethane, acetone, chloroform, ethyl acetate, carbon tetrachloride, methyl acetate, toluene and methanol are the favorite solvents for [HMIM] OTF. In addition, the solubility parameter of [HMIM] OTF at room temperature (298.15 K), which was obtained by linear extrapolation method, was 20.74 (J/cm3)0.5. This study could be used as a reference to the application and research of the ionic liquids.