Experimental and predicted phase equilibria and excess properties for systems with ionic liquids

Vapor–liquid equilibria (VLE) for the binary systems methylcyclohexane–toluene and 1-octene–n-octane and the ternary systems with the ionic liquid 1-hexyl-3-methyl-imidazolium bis(trifluoro-methylsulfonyl)imide [HMIM]+[BTI]− as entrainer were measured. The addition of the ionic liquid leads to an increase of the separation factors. Excess enthalpies (HE) were measured for methylcyclohexane and n-octane in the same ionic liquid as well. Furthermore activity coefficients at infinite dilution (γ∞) were determined for a few solutes in various ionic liquids such as 1-hexyl-3-methyl-imidazolium bis(trifluoro-methylsulfonyl)imide [HMIM]+[BTI]−, 1-hexyl-3-methyl-imidazolium trifluoro-methanesulfonate [HMIM]+[OTF]−, 1-methyl-1-octyl-pyrrolidinium bis(trifluoromethyl-sulfonyl)imide [MOPYR]+[BTI]−, 1-methyl-1-butyl-pyrrolidinium trifluoromethanesulfonate [MBPYR]+ [OTF]− and 1-ethyl-3-methyl-imidazolium ethyl sulfate [EMIM]+[EtOSO3]−. The γ∞-values were used to determine the selectivities Sij∞=γi∞/γj∞ and the capacities ki=1/γi∞ at infinite dilution. The experimental data with [R1R2IM]+[BTI]− were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.