By analysing two examples, i.e. the Langmuir type of exchange process and the autocatalytic reaction system, introduced by Schlogle to simulate phase tration of first order, it is demonstrated that critical phenomena of the bistability in chemical reactions can be also cast into the standard formulation of Landau (mean-field) theory of transitions. This reveals further the feature of second-order-like transition at the critical point of line of discontinuous transitions in bistable systems and shows also the generality of critical phenmena in different bistable systems, including the chemical ones. The Landau theory of transitions, related initially to the condensed matter in equilibrium state, is generalized to more varied and intersting systems, far from equilibrium.

Key words: PHASE EQUILIBRIUM, CHEMICAL REACTION, PHASE TRANSFORMATION THEORY, MEANFIELD THEORY, SELF-CATALYSIS, CRITICAL PHENOMENA