Liquid Liquid Equilibrium Data for the Separation of Acetone from <i>n</i>‑Heptane Using Four Imidazolium-Based Ionic Liquids

Ionic liquids (ILs) can serve as green alternative extractants to traditional solvents for the sustainable development of liquid–liquid extraction. Liquid–liquid equilibrium data for four systems of n-heptane + acetone + 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM]­[OTF]), n-heptane + acetone + 1-hexyl-3-methylimidazolium trifluoromethanesulfonate ([HMIM]­[OTF]), n-heptane + acetone + 1-butyl-3-methylimidazolium bis­((trifluoromethyl)­sulfonyl)­imide ([BMIM]­[NTf2]), and n-heptane + acetone + 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]­[PF6]) were tested at T = 298.15 K and P = 101.325 kPa in this work. By comparing the values of the distribution coefficients and separation factors, the experimental results showed that the order of extraction capacity of ILs as extraction solvent was [BMIM]­[OTF] > [BMIM]­[PF6] > [BMIM]­[NTf2] and [BMIM]­[OTF] > [HMIM]­[OTF]. Finally, the experimental data were regressed with the NRTL and UNIQUAC models, and the binary interaction parameters were obtained