Capacity of two 1-butyl-1-methylpyrrolidinium-based ionic liquids for the extraction of ethanol from its mixtures with heptane and hexane

In this work, the ionic liquids 1-butyl-1-methylpyrrolidinium dicyanamide, [BMpyr][N(CN)2], and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, [BMpyr][TfO], were studied as green solvents for the separation of ethanol from heptane and hexane. Liquid–liquid equilibrium (LLE) studies are important in the development of theoretical/semiempirical models for use in the design of extraction processes. Experimental liquid–liquid equilibrium (LLE) data were measured for the ternary systems {heptane or hexane (1) + ethanol (2) + [BMpyr][N(CN)2] (3)} and {heptane or hexane (1) + ethanol (2) + [BMpyr][TfO] (3)} at 298.15 K and atmospheric pressure. The effectiveness of the extraction of ethanol from the alkanes was evaluated by solute distribution ratio and selectivity values. Finally, the experimental tie-line data were accurately correlated with the non-random two liquid (NRTL) thermodynamic model.