Liquid−Liquid Equilibria of Ternary Systems Sulfide + Octane + Solvents at Different Temperatures

Abstract

Liquid-liquid equilibria (LLE) data of five ternary systems of sulfide + octane + solvents were measured at 313.15 K, 323.15 K, and 333.15 K, respectively, under atmospheric pressure. Dimethyl sulfoxide, sulfolane, and tetraethylene glycol were used as solvents, respectively. The distribution of sulfide (thiophene, n-butyl mercaptan, n-dibutyl sulfide) between the extract phase and the raffinate phase was obtained. The experimental data were correlated through the well-known NRTL and UNIQUAC models for the activity coefficient, and the model parameters were estimated using the simplex minimization method and a composition-based objective function. The results were analyzed in terms of average absolute deviations between experimental and calculated mass percentage of thiophene, n-butyl mercaptan, and n-dibutyl sulfide. The results were considered satisfactory, with the NRTL model yielding a better representation of the equilibria data for the systems studied. The two models were suitable for calculating the LLE data of these systems.