Liquid-Liquid Extraction of Toluene from Heptane Using [emim][DCA], [bmim][DCA], and [emim][TCM] Ionic Liquids

The performance of the 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]), 1-butyl-3-methylirnidazolium dicyanamide ([bmim][DCA]), and 1-ethyl-3-methylimidazolium tricyanomethanide ([emim][TCM]) ionic liquids (ILs) as alternative solvents in the liquid-liquid extraction of toluene from heptane was evaluated at 313.2 K. These ILs were selected due to their low viscosity and their highly aromatic character. Densities and viscosities of the ILs have also been determined over the temperature range from 293.15 to 353.15 K. To analyze the potential of the ILs to be applied in an industrial aromatic extraction process, toluene and heptane distribution ratios, separation factors, and physical properties of the ILs have been compared to the sulfolane values. In addition, the nonrandom two-liquid model successfully correlated the liquid-liquid equilibrium data for the three ternary systems studied.