Kinetic Characteristic Features of the Fast Relaxations of Chemical Reactions

• Published in: Russian journal of physical chemistry. B 2020-09, Vol.14 (5), p.765-772
• Main Author: Kol’tsov, N. I.
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Chemistry and Materials Science; Kinetics and Mechanism of Chemical Reactions; Physical Chemistry
• ISSN: 1990-7931; 1990-7923
• DOI: 10.1134/S1990793120050061

Fast changes in the kinetic characteristics occur at the beginning of the transition processes of nonlinear chemical reactions, which are often not observed during nonstationary experiments. These periods of fast relaxations may carry important information about the mechanisms of complex reactions. The evolution of the period of fast relaxations of typical chemical reactions as they move away from equilibrium is studied in this paper. A three-level classification of the forms of nonequilibrium kinetic dependences with respect to the level of informativity is introduced. Nonmonotonic curves with bends (ravines, hills) have the maximum informativity, monotonic curves with bends (waves) have the average informativity, and monotonic curves without bends (descents, ascents) have the minimum informativity. The criterion of existence of the period of fast relaxations, during which the informative forms of the kinetic curves (ravines, hills, waves) exist, is formulated. It is shown that the states of false equilibrium can be observed during their study in which kinetic curves seem to be constant far from the equilibrium. The obtained results may be useful in the reconstruction of the mechanisms of chemical reactions.