Isobaric vapor–liquid equilibrium for binary and ternary systems with toluene, 2-methoxyethanol and dimethyl sulfoxide at 101.3 kPa

Isobaric vapor–liquid equilibrium (VLE) data for binary systems of toluene + 2-methoxyethanol, 2-methoxyethanol + dimethyl sulfoxide (DMSO) and toluene + DMSO were obtained by using a Fischer VLE 602 equipment at 101.3 kPa, as well as for the ternary system of toluene + 2-methoxyethanol + DMSO. The binary VLE data were considered to be thermodynamically consistent according to the Wisniakʹs modification of the Herington test and the Wisniakʹs L–W test. It was determined that toluene and 2-methoxyethanol form binary azeotrope at 379.08 K, 70.2 mol% toluene at 101.3 kPa. The binary VLE data were correlated by using Wilson, NRTL and UNIQUAC models with minor deviations. The ternary system was well predicted from binary interaction parameters and passed both the Wisniak–Tamirʹs modification of McDermott–Ellis test and the Wisniakʹs L–W test. Besides, the ternary VLE data were also satisfactorily correlated by using Wilson, NRTL and UNIQUAC models. Moreover, the change of phase equilibria behavior of toluene and 2-methoxyethanol due to the addition of DMSO is significant. Therefore, DMSO is recommended as a promising entrainer for the separation of toluene and 2-methoxyethanol azeotropic mixture by extractive distillation.