The activity coefficients at infinite dilution (γ13∞) for 31 solutes, from the following classes of compounds: alkanes, cycloalkanes, alkenes, cycloalkenes, aromatic hydrocarbons, alcohols, ketones, acetonitrile, thiophene and water were determined using an ionic liquid (IL) modified column utilizing gas liquid chromatography. In this work, N-(2′, 3′-epoxypropyl)-N-methyl-2-oxopyrrolidinium chloride IL was used to determine the activity coefficients of organic solutes in the range of temperatures from T = 323.15 K–343.15 K, using 10 K intervals, under atmospheric pressure. From these experimental γ13∞ data, the following thermodynamic properties at infinite dilution, including partial molar excess Gibbs free energies (ΔGiE,∞), enthalpies ΔHiE,∞and entropy TrefΔSiE,∞ were computed. Furthermore, selectivity (Sij∞) and capacity (Kj∞) were also calculated from experimental value of γ13∞ for separation of mixtures such as (heptane/benzene, heptane/thiophene, hexane/benzene, water/butanol and hexane/ethanol) at T = 323.15 K–343.15 K. Generally, the results of this work indicate that the investigated IL has good potential for separating aliphatic solutes from aromatic ones. Specifically, the chosen IL reduces the retention time of most of the solutes used, compared to other reported ILs. Furthermore, the findings of this study suggest that this IL [N(2′,3′-epoxypropyl)-N-methyl-2-oxopyrrolidinium chloride] may be useful for future applications such as separation and purification in petrochemical industries.
