Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate

• γ∞γ∞ and KL for 65 solutes in the IL [C2OHmim][FAP] were determined by IGC.
• Partial molar thermodynamics functions ΔG1E,∞, ΔH1E,∞ and ΔS1E,∞ were calculated.
• Selectivities and capacities for alkanes/thiophene separation problems were calculated.
• LFER system constants as a function of T for [C2OHmim][FAP] were calculated.
• Results were compared to other ILs based on the same cation and anion.

This work presents new data of activity coefficients at infinite dilution, γ∞ of different organic solutes and water in the 1-(2-hydroxyethyl)-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate, [C2OHmim][FAP] ionic liquid. Values of γ∞ were determined for 65 organic solutes, including alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, aldehydes, acetonitrile and water by inverse gas chromatography within the temperature range from (318.15 to 368.15) K. The basic thermodynamic functions, such as partial molar excess Gibbs energies, ΔG1E,∞, enthalpies, ΔH1E,∞ and entropies, ΔS1E,∞ at infinite dilution were calculated from the experimental γ∞ values obtained over the temperature range. Additionally the gas–liquid partition coefficients, KL were determined. Experimental values of gas–liquid partition coefficients were used to determine the coefficients in the Abraham solvation parameter model (LFER). Results are compared to previously investigated ionic liquids with the same [C2OHmim]+ cation and [FAP]− anion. The selectivity and capacity at infinite dilution for alkanes/thiophene extraction problems were calculated from experimental γ∞ values to verify the possibility of investigated ionic liquid as an entrainer in liquid–liquid extraction.