Is Flory's model the best tool for studying the thermodynamic properties of any kind of binary mixtures? A critical study of selected binary systems of hydrocarbons

The asymmetric and symmetric Flory equations describing the excess molar enthalpy, H-E, for 13 systems divided into four groups ((a) hexane + heptane or octane or dodecane or hexadecane; (b) dodecane + hexane or 2-methylpentane or 3-methylpentane or 2,2-dimethylbutane or 23-dimethylbutane; (c) hexane + cyclohexane or benzene, cyclohexane + benzene; (d) cyclohexane + cis-decalin or trans-decalin) were used. On the basis of this, the interaction parameters, X-AB, were obtained, and next, they were used for the prediction of excess molar volumes, V-E, for all the mixtures under test. The Prigogine-Flory-Patterson contributions to H-E and V-E were established. The results obtained were compared with those found in the literature that have been calculated by the Flory's model in the traditional way. The discussion on the prediction abilities of the model used for all the systems is given. (c) 2005 Elsevier B.V. All rights reserved.