Determination of activity coefficients at infinite dilution of water and organic solutes (polar and non-polar) in the Ammoeng 100 ionic liquid at T = (308.15, 313.5, 323.15, and 333.15) K

Activity coefficients at infinite dilution (γ13∞) have been determined for 27 solutes, viz. water and organic compounds (n-alkanes, cycloalkanes, 1-alkenes, 1-alkynes, aromatics, alcohols, and ketones) in the ionic liquid Ammoeng 100, by gas–liquid chromatography at four different temperatures, T = (308.15, 313.15, 323.15, and 333.15) K. Columns with different phase loadings (20 to 24)% of the ionic liquid in the stationary phase were employed to obtain γ13∞ values at each temperature investigated. Partial molar excess enthalpies at infinite dilution (ΔH1E,∞) were calculated for the solutes from the temperature dependency relationship of the ln(γ13∞) values for the temperature range in this study. The uncertainties in the determinations of the γ13∞ and ΔH1E,∞ values are 6% and 10%, respectively. Selectivity values at infinite dilution (Sij∞), have been computed from the γ13∞ values to assess the potential candidacy of the Ammoeng 100 ionic liquid for the separation of alkane/alcohol mixtures. The results from this study have been compared to those available for several ionic liquids from previous investigations.

► Activity coefficients at infinite dilution in the ionic liquid Ammoeng 100. ► Twenty-seven solutes investigated at T = (308.15, 313.15, 323.15, and 333.15) K. ► Ammoeng 100 not suited to aromatic/aliphatic and alkane/alcohol separations.