Global phase diagram for reacting systems

The global phase diagram of a chemically reactive system is described for a model which can be thought of as the "regular-solution" model of a ternary mixture. We consider the particular addition reaction X + Y → Z and analyze the significant features of the phase diagrams which result from the intersection of the chemical equilibrium surface and the phase coexistence manifolds for all possible values of the energy parameters. Based on the nature of molecular interactions, six different general kinds of mixtures can be identified where interesting phenomena such as triple and quadruple points, closed-loop phase coexistence curves, lower and upper areatropy, and critical areatropy appear as a consequence of chemical and phase equilibrium interaction.