Experimental research and mathematical modeling of vapor-liquid equilibrium in the ternary benzene—hexafluorobenzene—dimethyl sulfoxide system

Data on vapor-liquid equilibrium in benzene—DMSO, hexafluorobenzene—DMSO, and benzene—hexafluorobenzene—DMSO systems were obtained in the full-scale experiment. The ternary system is characterized by a specific ratio of the component boiling point differences: -0.5 °С in the biazeotropic component benzene—hexafluorobenzene and more than 100°C in the zeotropic benzene—DMSO and hexafluorobenzene—DMSO constituents. The Wilson equation parameters for the systems with large boiling point differences were evaluated using two sets of experimental data. A satisfactory description of the phase equilibrium was obtained. The values of the relative volatility of the hexafluorobenzene—benzene pair indicate the selectivity of DMSO in the process of extractive distillation of a biazeotropic mixture of different composition.