Activity coefficients at infinite dilution of organic solutes in the ionic liquid ethyl(2-hydroxyethyl)dimethyl-ammonium diethylphosphate using gas–liquid chromatography

The activity coefficients at infinite dilution, γi∞, of 22 organic solutes in the ionic liquid ethyl(2-hydroxyethyl)dimethyl-ammonium diethylphosphate have been determined using gas–liquid chromatography at the temperatures ranging from 323.15 to 363.15 K. The partial molar excess enthalpies at infinite dilution, HiE,∞, of the solutes in the ionic liquid were calculated from the temperature dependence of the experimental γi∞ values. The selectivity for the hexane/benzene and cyclohexane/benzene separation problems were also derived from γi∞ and compared to the literature values for other ionic liquids and N-methyl-2-pyrrolidone.

► A hydroxyl contained ionic liquid
► One-step synthesis and cheap.
► Acceptable selectivity for the separation of aliphatics from aromatics.