Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Densities and viscosities for three binary systems, cyclohexane + toluene, cyclohexane + decalin, and toluene + decalin, at T ) (283.15, 293.15, 303.15, 313.15, and 323.15) K have been measured over the whole composition range and atmospheric pressure along with the properties of the pure components. Viscosities deviations and excess molar volumes for the binary systems at the above-mentioned temperatures were calculated from experimental data and fitted to the Redlich-Kister expansion. In addition, the Prigogine-Flory-Patterson (PFP) model was used to correlate experimental density data. The Redlich-Kister expansion well correlated viscosity deviation and excess volume values. Shape and length asymmetries and molecular interaction asymmetries impact on viscosity deviations, but the latter had a more pronounced influence. Negative excess molar volumes were found when only shape and length asymmetries were present, while molecular interaction asymmetries led to positive values. The effects of simultaneous molecular interaction and length asymmetries were somehow additive for excess volume. The Prigogine-Flory-Patterson model well correlates density data and predicts qualitatively the excess molar volumes, but does not predict the temperature dependence on this property. Moreover, the results lead to the conclusion that the model fails when the molecular interaction term is omitted, even when the system presents only shape and length asymmetries.