Liquid–liquid equilibrium (LLE) data for ternary mixtures of [C4DMIM]—[PF6]+[PCP]+[water] and [C4DMIM][PF6]+[PA]+[water] at T = 298.15 K and p = 1 atm

• LLE of pentachlorophenol/phthalic acid–[C4DMIM][PF6]–water was reported.
• Ternary plots indicate favorable sloping of the tie lines toward the ionic liquid.
• High values of selectivity ∼24–29 for PA and ∼106–293 for PCP was obtained.
• The UNIQUAC and NRTL models were used to correlate the experimental data.
• Reliability of experimental tie-line results were also confirmed using models.

Pentachlorophenol (PCP) and phthalic acid (PA) are toxic chemicals and are commonly known as endocrine disrupting compounds (EDCs). This study reports the extraction of these two EDC compounds from aqueous phase using imidazolium based ionic liquid (IL) namely 1-butyl-2,3-dimethylimidazolium hexaflourophosphate [C4DMIM][PF6]. An experimental investigation of liquid–liquid equilibrium (LLE) behavior of [C4DMIM][PF6] (1) + PCP (2) + water (3) and [C4DMIM][PF6] (1) + PA (2) + water (3) was carried out at T = 298.15 K and p = 1 bar. Information obtained from the ternary plots indicates a favorable sloping of the tie lines toward the IL. The selectivity and distribution coefficients determined from the tie line data confirmed high values of selectivity ∼24–29 for PA and ∼106–293 for PCP. The UNIQUAC and NRTL models were then used to correlate the experimental data and to predict the equilibrium phase compositions with a Root Mean Square Deviation (RMSD) value below unity. For each ternary system, the Othmer–Tobias and Bachman correlation was also studied to verify the reliability of the experimental tie–line results.