Theory of Binary Azeotropes

Abstract

WE have recently had occasion to survey critically the sparse literature concerned with the theory of azeotropes and have been led to the conclusion that the most general, albeit formally exact, thermodynamic treatment is of little practical use^1,2. Logical extension of the statistical thermodynamic treatment of strictly regular solutions³ indicates that azeotropes formed by such solutions would obey the empirical rules of behaviour of real azeotropes which have been advanced by Timmermans, Merriman and Wrewsky. Moreover, we find that closely approximate relations between N₂, P and T (N₂ being the mol fraction of component 2), derivable from the treatment, do in fact describe the behaviour of many of the azeotropic systems which have been experimentally studied.