Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Four pyridinium-based ionic liquids {N-ethylpyridinium ([epy]), 2-methyl-N-ethylpyridinium ([2empy]), 3-methyl-N-ethylpyridinium ([3empy]), and 4-methyl-N-ethylpyridinium ([4empy]), all with the anion bis(trifluoromethylsulfonyl)imide ([Tf2N])} were investigated for the first time as solvents in the liquid-liquid extraction of aromatics. Liquid-liquid equilibrium (LLE) data for the four ternary systems {heptane + toluene + [epy][Tf2N], or [2empy][Tf2N], or [3empy][Tf2N], or [4empy][Tf2N]} were determined at T/K = 313.2 and atmospheric pressure. The degree of consistency of the experimental LLE data was ascertained by applying the Othmer-Tobias correlation. The phase diagrams for the ternary systems were plotted, and the tie lines correlated with the NRTL model were compared satisfactorily with the experimental data. Finally, the selectivity and extractive capacity, derived from the LLE data, were calculated and compared to those previously reported in the literature for the system {heptane + toluene + sulfolane} to evaluate the feasibility of using these ionic liquids as solvents for the extraction of aromatics from aliphatic hydrocarbons.