Theory of phase diagrams and azeotropic conditions for two-phase reactive systems

Abstract

Expressions for the partial derivatives of the intensive properties that characterize the equilibrium states in two-phase systems, in which the components undergo one equilibrium chemical reaction, are derived. The necessary and sufficient conditions for an azeotropic transformation to occur are found. It is shown that whereas stationary points in the isobaric temperature-composition or isothermal pressure-composition equilibrium surfaces correspond to the formation of reactive azeotropes, reactive azeotropes do not necessarily correspond to stationary points in these equilibrium surfaces. The conditions under which reactive azeotropes are not equivalent to stationary points in the equilibrium surfaces are presented.