Activity coefficients at infinite dilution of organic solutes in methylphosphonate based ionic liquids using gas-liquid chromatography

• Measurements of activity coefficients at infinite dilution using GLC.
• Organic solvents in methylphosphonate based ionic liquids.
• High selectivity for different problems of separation.
• LSER correlation was presented.

Activity coefficients at infinite dilution γ12∞ were determined for organic solutes in two ionic liquids 1-ethyl-3-methylimidazolium methylphosphonate [EMIM][(MeO)(H)PO2] and 1.3-dimethylimidazolium methylphosphonate [DMIM][(MeO)(H)PO2] by gas-liquid chromatography at temperatures within the range (313.15 to 373.15) K. The values of the selectivity and capacity for few separation problems cyclohexane/benzene, cyclohexane/thiophene and cyclohexane/pyridine were calculated from activity coefficients at infinite dilution data and compared to literature values for other ionic liquids and some industrial solvents such as sulfolane, N-methyl-2-pyrrolidone (NMP) and N-formylmorpholine (NFM). The selectivity values of both ILs investigated in this study are greater than that for NMP, NFM, and sulfolane. These results indicate the potential use of the two ILs in extractive separation processes.

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