par Prigogine, Ilya ;Desmyter, Aline
Référence Transactions of the Faraday Society, 47, page (1137-1142)
Publication Publié, 1951
Article révisé par les pairs
Résumé : Considering an associated binary solution, e.g. alcohol + carbon tetrachloride, as a system of single molecules and associated complexes in equilibrium with one another, it has been shown in a previous paper, by using the principle of detailed balancing of elementary processes, that the relation fA/fB = α holds between the activity coefficients if the deviations from the laws of perfect solutions can be entirely ascribed to the presence of the complexes, α denotes the fraction of molecules of the associated constituent which appear as single molecules. This relation, which is completely independent of any hypothesis about the mode of association, can be checked by comparing thermodynamic measurements of fA and f B with values of α obtained from the spectroscopic study of the intensity of the OH vibration band. We have measured the partial vapour pressures of the system: tert.-butyl alcohol + carbon tetrachloride, tert.-butvl alcohol + cyclohexane, tert.-butyl alcohol + carbon disulphide, for which the spectroscopic values of α are known. In all three cases, as in those studied in our previous work, the relation fA/fB = α holds quite well, except for high concentrations of alcohol. The Gibbs excess free energy has been calculated for the systems mentioned above and for the system methanol + carbon tetrachloride. From the comparison of the thermodynamic data for fA/fB and the spectroscopic data for α it is possible to make a rather accurate estimation of the part of the excess free energy which must be attributed to the presence of the complexes.