Liquid-liquid equilibrium data (LLE) for the mixtures of ionic liquid (IL) + alkane + aromatic {1-butylpyridinium nitrate, [BPy] [NO3] (1) + heptane, octane, or decane (2) + ethylbenzene (3)} and {[BPy][NO3] (1) + heptane, octane, or decane (2) + p-xylene (3)} at T = 298.15 K and P = 89 Kpa were measured. The degree of reliability of the experimental LLE data was examined by using the Othmer-Tobias and Hand correlation. For the six studied ternary mixtures, the separation factor and distribution ratio of aromatic hydrocarbons derived from LLE data and were applied to determine if [BPy] [NO3] can be used as dearomatization solvent. The separation of aromatic compounds with similar molecular weight (ethyl benzene and p-xylene) from alkanes demonstrates that p-xylene can be separated more easily from alkanes. The triangular phase diagrams for all studied systems were sketched, and the tie lines were compared with the NRTL model.