Measurements of activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium ethylphosphonate [EMIM][(EtO)(H)PO2] using gas-liquid chromatography

Activity coefficients at infinite dilution γ12∞ and gas-liquid partition coefficients KL of selected hydrocarbons, alcohols, haloalkanes, nitrogen and sulfur containing compounds in the ionic liquid 1-ethyl-3-methylimidazolium ethylphosphonate [EMIM][(EtO)(H)PO2] were determined by inverse gas chromatography at five temperatures within the range (323.15 to 363.15) K. Retention data were used to calculate the selectivity and capacity for four separation problems hexane/benzene, hexane/thiophene, hexane/pyridine and cyclohexane/benzene. The selectivity values of 1-ethyl-3-methylimidazolium ethylphosphonate investigated in this study are greater than those obtained with sulfolane and N-methyl-2-pyrrolidone (NMP). These results indicate the potential use of the IL in extractive separation processes.