Belousov-Zhabotinskii reaction mechanism

Qualitative description of mechanism of the Belousov-Zhabotinskii reaction (the Fields-Koros-Noyes mechanism)... 

The mechanism of the Belousov-Zhabotinskii reaction can be considered using a simple Oregonator model. For the reaction... 

I present in this chapter a short discussion of chemical reaction rate laws and mechanisms, and of nonlinear ordinary and partial differential equations. To strengthen the connection between this review material and the later chapters, I have drawn the examples and problems here from literature relevant to the Belousov-Zhabotinskii reaction. 

To illustrate the experimental determination of rate constants and mechanisms we turn to another set of reactions important in the mechanism of the Belousov-Zhabotinskii reaction. The overall reaction for the bromination of malonic acid is... 

Show that the differential equation (4.9) (the induced kinetic differential equation of the Field-Koros-Noyes mechanism model of the Belousov-Zhabotinskii reaction) does have periodic solutions at certain values of the parameters. 

Belousov-Zhabotinskii reaction (B-Z reaction) An oscillating chemical reaction in which there are periodic oscillations in the color of a mixture of sulfuric acid, potassium bromate, cerium (or iron) sulfate, and propanedioic acid. The period of oscillation is about one minute. The color changes are caused by repeated oxidations and reductions of cerium (or iron) ions. The reaction was first observed by the Russian chemist B. P. Belousov in the case of cerium and modified to iron by A. M. Zhabotinskii in 1963. The mechanism of the B-Z reaction is highly complicated and involves a large number of individual steps. 

Field, R. J. Forsterling, H. D. 1986. On the Oxybromine Chemistry Rate Constants with Cerium Ions in the Field-Koros-Noyes Mechanism of the Belousov Zhabotinskii Reaction, J. Phys. Chem. 90, 5400-5407. 

Recently there has been an increasing interest in self-oscillatory phenomena and also in formation of spatio-temporal structure, accompanied by the rapid development of theory concerning dynamics of such systems under nonlinear, nonequilibrium conditions. The discovery of model chemical reactions to produce self-oscillations and spatio-temporal structures has accelerated the studies on nonlinear dynamics in chemistry. The Belousov-Zhabotinskii(B-Z) reaction is the most famous among such types of oscillatory chemical reactions, and has been studied most frequently during the past couple of decades [1,2]. The B-Z reaction has attracted much interest from scientists with various discipline, because in this reaction, the rhythmic change between oxidation and reduction states can be easily observed in a test tube. As the reproducibility of the amplitude, period and some other experimental measures is rather high under a found condition, the mechanism of the B-Z reaction has been almost fully understood until now. The most important step in the induction of oscillations is the existence of auto-catalytic process in the reaction network. 

Oscillatory reactions are a typical class of phenomena, which display unusual features. After the discovery of Belousov-Zhabotinskii (B-Z) reaction, there has been a tremendous flurry of activity [1] and a large number of such reactions have been discovered during recent years. Biochemical reactions [2-10] such as glycolytic oscillations and peroxidase catalysed oxidation of nicotinamide adenosine deoxyhydrogenase (NADH) have also generated considerable interest. The interest in such reactions is stiU sustained in view of their importance in understanding cardiac and neuronal oscillations. In the case of many oscillatory chemical reactions [1], detailed reaction mechanisms have been postulated and verified with the help of numerical computation. This has also been particularly so for B-Z reaction where Field-Koros-Noyes (FKN) mechanism [11] has been invoked. 

Effects of added salts on the Belousov-Zhabotinskii oscillating reaction have also been attributed to solvent structural factors, through the influence of the cations (Li+, Na+, K+, Me4N+) on the water structure. Specific effects of added salts on transition states have been proposed for the reactions of cobalt(ii) with chlorophyllic acid (in methanol) and the conversion of / - into -dodeca-molybdosilicate. In the former case added lithium nitrate is thought to inhibit solvation of the transition state, but in the latter added ions are believed actually to enter the transition state. Salt effects on the kinetics and mechanism of formation of monofluoro-complexes of a range of M + and Al + cations in aqueous media are described in a conference report comprehensible only to readers of Russian. 

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