Measurements of activity coefficients at infinite dilution of organic solutes and water in 1-propyl-1-methylpiperidinium bis{(trifluoromethyl)sulfonyl}imide ionic liquid using g.l.c.

Abstract

Activity coefficients at infinite dilution ( γ 13 ∞ ) of 38 different solutes (including alkanes, cyclohydrocarbons, alkenes, alkynes, benzene, alkylbenzenes, alcohols, water, thiophene, THF, MTBE, ethers, acetone, and n-ketones) in the ionic liquid 1-propyl-1-methylpiperidinium bis{(trifluoromethyl)sulfonyl}imide have been determined by using the g.l.c. method and have been reported over the temperature range from (308.15 to 358.15) K. The partial molar excess enthalpies of mixing at infinite dilution have been determined based on temperature dependence of γ 13 ∞ and discussed in terms of the intermolecular interactions. Selectivity and capacity at infinite dilution has been also calculated for chosen separation processes in systems ( n-hexane + benzene) and (cyclohexane + benzene) to evaluate if the studied ionic liquid is capable to be a good entrainer for these processes, e.g. in the liquid–liquid extraction. The results obtained are much better than many other ionic liquids with bis{(trifluoromethyl)sulfonyl}imide-based anion. However, the results are worse than for the thiocyanate-based ionic liquids.