Liquid−Liquid(−Liquid) Equilibria in Ternary Systems of Aliphatic Hydrocarbons (Heptane or Octane) + Phenols + Water

Abstract

The liquid−liquid equilibria (LLE) and liquid−liquid−liquid equilibria (LLLE) in eight ternary systems were determined by photometric turbidity titration at atmospheric pressure. Additionally, the compositions of coexisting phases were determined with analytic methods. The measurements in the systems heptane or octane + phenol + water were realized at temperatures of (313.15 and 333.15) K. The equilibrium data in the systems heptane + 2-cresol or 3-cresol or 4-cresol + water and octane + 2-cresol or 3-cresol or 4-cresol + water were estimated at temperatures of (298.15 and 323.15) K. The excess Gibbs energy nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) activity coefficient models as well as the Elliott−Suresh−Donohue equation of state (ESD EoS) were used to predict the LLE or LLLE in the investigated ternary systems. The binary interaction parameters were calculated using vapor−liquid and LLE data from the literature or data predicted with the modified universal quasichemical functional-group activity coefficient (UNIFAC Dortmund) model.