ANALYSIS OF FLUCTUATION PROCESSES IN SYSTEM OF CYSTEINE-OXYGENATED COBALT (II) COMPLEXES WITH o-DISALICYLIDENEPHENILENEDIAMINE AND CYTOSINE USING NON-EQUILIBRIUM THERMODYNAMIC METHOD

Abstract

The results of the analysis of chemical oscillations in a homogeneous system of cysteine - oxygenated cobalt (ΙΙ) complexes with o-disalicylidene phenylene diamine and cytosine based on the principles of nonlinear nonequilibrium thermodynamics are presented. The approach allows predicting the evolution of processes far from equilibrium, establishing criteria and driving forces for the developing of critical phenomena in the system. The thermodynamic description of highly nonequilibrium processes was performed on the basis of evaluation and analysis of the nature of the change in the second variation of entropy derivative δ2S, which is presented as the derivative of the Lyapunov thermodynamic function. In order to solve the problem, the mechanism was justified and a kinetic diagram of the processes occurring during the liquid-phase oxidation of cysteine in the presence of complex compounds of cobalt (II) with o-disalicylidenephenylenediamine, cytosine, and molecular oxygen was used. Based on the expressions of the variation in chemical affinity of the reaction mixture, referred to temperature, and the variation in thermodynamic flow, an expression for the derivative of the thermodynamic Lyapunov function was derived. The thermodynamic analysis of the liquid-phase oxidation of the biosubstrate under study in the presence of mixed ligand cobalt (II) complexes by the indicated ligands in the vibrational mode based on the nature of the change in the derivative of the Lyapunov function allows to establish the reasons of oscillation processes in the considered homogeneous catalytic system. The loss of stability during redox processes in the system under study and their transition to a fluctuation mode occurs as a result of the strong remoteness of the processes under consideration from chemical equilibrium and, associated with this, the nonlinearity of the system, the presence of autocatalytic stages, as well as positive feedbacks was found.