POLYMORPHIC KINETICS: CHAOS IN LINEAR HOMOGENEOUS CHEMICAL REACTIONS

The study of the mechanisms and causes of critical phenomena and chaotic oscillations in the kinetics of homogeneous chemical reactions, as well as the search for appropriate examples of such reactions, is a relevant area of development of ideas about self-organization processes that play an important role in the evolution of living nature. It is known that the main condition for the existence of complex-periodic and chaotic undamped oscillations is the transition of a dynamic chemical system to such an unstable stationary state in which stable stationary states are inaccessible (absolute instability). The literature contains the necessary conditions for the emergence of unstable stationary states (the Bendixson-Dulac criterion, etc.). The exact conditions for the birth and death of chaotic regimes are still unknown. Dynamic models of chemical reactions are systems of ordinary differential equations based on reaction mechanisms and the corresponding kinetic laws associated with the reaction environment (ideal, non-ideal). At present, examples of chaotic dynamics models are known for homogeneous chemical reactions proceeding according to nonlinear stage schemes with classical kinetics of the law of mass action. In this paper, the possibility of describing chaotic oscillations in homogeneous chemical reactions proceeding according to linear stage schemes in an isothermal reactor of ideal mixing with a new kinetic law, which is called "polymorphic", is investigated. Polymorphic kinetics generalizes the known kinetic laws - the ideal law of Hulbert-Waage mass action and the non-ideal kinetic law of Marcelin-De Donde. Unlike these laws, polymorphic kinetics takes into account the possible mutual influence of reagents in each elementary stage of a chemical reaction. It is shown that polymorphic kinetics allows describing complex oscillatory and chaotic dynamics of chemical reactions by simple linear mechanisms with respect to key (determining the dynamics) reagents. Examples of reactions are given for which, within the framework of polymorphic kinetics, the existence of experimentally observed chaos has been numerically reproduced and proven using the Shilnikov criterion and Lyapunov exponents. For citation: Kol'tsov N.I. Polymorphic kinetics: chaos in linear homogeneous chemical reactions. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 2. P. 50-58. DOI: 10.6060/ivkkt.20266902.7208.