Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The work presented focused on the experimental liquid-liquid phase equilibrium measurements in ternary systems {ionic liquid (1) + hex-1-ene (2) + hexane (3)} and (ionic liquid (1) + cyclohexene (2) + cyclohexane (3)} at temperature T = 298.15 K and ambient pressure. The dicyanamide-based ionic liquids (ILs) were discussed as solvents for two types of separation problems of hexane/hex-1-ene and cyclohexane/ cyclohexene. The objective of this work was to explore the feasibility of six ILs, namely N-ethyl-Nmethylmorpholinium dicyanamide, [EMMor][DCA], (3-hydroxypropyl)-1-methylmorpholinium dicyanamide, [N-C3OHMMor][DCA], 1-(3-hydroxypropyl)-3-methylimidazolium dicyanamide, [N-C3OHMIM] [DCA], 1-(3-hydroxypropyl)pyridinium dicyanamide, [N-C3OHPy][DCA], (3-cyanopropyl)pyridinium dicyanamide, [N-C3CNPy][DCA] and (3-cyanopropyl)methylpyrrolidinium dicyanamide,[N-C3CNMPyr] [DCA]. The separating ability of the investigated ILs was compared with the previously measured by us in ternary LLE ILs for these chosen separation problems. The effect of cation for the same anion was examined with respect to the selectivity and solute distribution ratio in these processes. The separation effectiveness of the [N-C3CNMPyr][DCA] in comparison with other ILs used in this work is the best for hexane/ hex-1-ene separations but lower than those presented by us earlier for [EMIM][DCA], however with better solute distribution coefficient. The experimental tie-lines were correlated with the non-random two liquid NRTL model. The proposed [N-C3CNMPyr][DCA] may be used as an alternative solvent for the separation of alkenes from alkanes and [EMMor][DCA] for cyclohexane/cyclohexene separation.