Measurement and Thermodynamic Modeling of Ternary (Liquid + Liquid) Equilibrium for Extraction of Phenols from Alkane with Furfural

The extraction process as a kind of energy-saving and environmental protection technology can be used to separate phenols from low-temperature coal tar. The liquid–liquid equilibrium (LLE) data regarding ternary systems n-heptane + phenols + furfural were determined experimentally at 303.2, 323.2, and 343.2 K under the atmospheric pressure condition, where phenols refer to phenol, p-cresol, and 2,6-xylenol. The solvent extraction capacity was assessed by the solute distribution coefficient and selectivity. Othmer–Tobias and Bachman equations were utilized to validate the consistency of the measured data, which the linear correlation (R 2) ≥ 0.99. Experimental LLE data were correlated utilizing the NRTL and UNIQUAC thermodynamic models with all of the RMSD and AARD values below 0.01, meaning that each ternary system is satisfactorily in agreement at temperatures studied and the NRTL model gives better agreement than the UNIQUAC model for ternary systems.