Experimental study and modelling of volumetric properties, viscosities and refractive indices of binary liquid mixtures benzene + PEG 200/PEG 400 and toluene + PEG 200/PEG 400

Densities, viscosities and refractive indices of four binary systems benzene + PEG 200, benzene + PEG 400, toluene + PEG 200 and toluene + PEG 400 were measured at ten temperatures (288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, 323.15, 328.15, 333.15 K) and at atmospheric pressure. From these data, excess molar volumes, viscosity deviations and deviations in refractive index were calculated and fitted to the Redlich–Kister equation. The obtained results have been analyzed in terms of specific molecular interactions and mixing behaviour between mixture components, taking into considerations effect of temperature on them. The refractive indices of binary mixtures were predicted by various mixing rules and compared with experimental data. The viscosity modelling was done by two types of models: group contribution UNIFAC–VISCO and ASOG–VISCO and correlative Teja–Rice and McAllister equations. The experimental values of viscosity were used to determine the interaction parameters of following groups CHarCH2O, CHarCar, CarCH3, CarCH2, CarOH and CarCH2O for their application in the UNIFAC–VISCO model. The same approach was used for calculation of following binary interaction parameters used in ASOG–VISCO model: CHarCH2O, CHarCar, CarCH2, CarOH and CarCH2O.

► Experimental values of ρ, nD and η of benzene (or toluene) + PEG 200 (or + PEG 400).
► Negative VE and Δη for all binary systems – strong hydrogen bonding interactions.
► Limited miscibility of toluene + PEG 200 system.
► Viscosity modelling with UNIFAC–VISCO and ASOG–VISCO models.