A Convenient Hybrid Method for Obtaining Liquid–Liquid Equilibrium Data in Ternary Systems

Liquid–liquid equilibrium data for ternary systems are scarce in literature, although they are important both for industry and simulations. Investigating ternary systems is usually costly and labor-intensive. We propose a nontraditional approach to determine liquid–liquid phase equilibrium in ternary systems. Our method generates tie line equilibrium compositional data based on a hybrid method combining traditional and noninvasive experimental procedures (cloud point titration and refractometry) and modern-day computational methodology centered on an-error-in-variables probability model. A series of Monte Carlo simulations were also conducted based on this computational methodology in order to estimate uncertainties in a mass balance numerical criterion derived from the lever rule. The results yielded by the model were validated by measuring four ternary systems containing acetonitrile, ethyl acetate, water, chloroform, ethanol, trichloroethylene, cyclohexane, and isooctane at atmospheric pressure and 294.15 K. The tie-lines for chloroform (1) + water (2) + acetonitrile (3) and cyclohexane (1) + ethyl acetate (2) + acetonitrile (3) are reported for the first time.