Collect. Czech. Chem. Commun. 1979, 44, 1841-1851

New possibilities of applications of the Barker quasi-lattice theory. Some relations between excess functions at infinite dilution

Vladimír Dohnal, Robert Holub and Jiří Pick

Department of Physical Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


A relation for the limiting activity coefficient and for the partial excess enthalpy of binary solution was derived from the Barker quasi-lattice theory. On the basis of these equations we found the relations between γi##h or hiE ##h for some groups of related binary systems in an especially simple form so that is it possible to convert these quantities from one system to another without the evaluation or knowledge of adjustable energy parameters. For some predictions it is only necessary to choose a geometrical model of molecules involved in them. The relations were obtained for binary systems whose one component is formed by monotonous molecules varying in size (such as n-alkanes) and the other component is arbitrary. A very simple relation also holds for limiting activity coefficients of substances forming homologous series in two arbitrary solvents. The practical utility and accuracy of the relations obtained is demonstrated on a number of examples. The agreement with experimental data is excellent for absolute majority of the systems tested.