Chemical reactions oscillating

Transition metal coordination compounds in oscillating chemical reactions. K. B. Yatsimirskii and L. P. Tikhonova, Coord. Chem. Rev., 1985, 63,241 (90). 

Subsequent to a fire in a teaching laboratory, it was discovered that a mixture of equal weights of the three dry solids, itself stable, reacted violently when wetted with up to two parts of water and was capable of igniting paper. All components (which exhibit an oscillating chemical reaction in solution) were necessary for this effect. 

The Belousov-Zhabotinskii reaction is a typical oscillating chemical reaction. Spiral structures form periodically, disappear and reappear as the result of an autocatalytic reaction, the oxidation of Ce3+ and Mn2+ by bromate (lessen, 1978). 

KOrOs and M. Burger, Bromide selective electrode for use in following the Zhabotindu-type oscillating chemical reaction, in Ion-Selective Electrodes (ed. E Pungor), Symposium 1972, Akademiai Kiad6, Budapest (1973), p. 191. Koryta,y4na/. Chim. Acta 61, 329 (1972). 

Fig. 19. 2-D MR image of an oscillating chemical reaction occurring within a bed of diameter 15 mm packed with 1-mm-diameter glass beads. In-plane resolution was 195 pm x 195 pm, and the image slice thickness was 1 mm. A single image was acquired in 1 s. Chemical waves are imaged as a result of the...

I. R. Epstein and J. A. Pojman, An Introduction to Nonlinear Chemical Dynamics Oscillations, Waves, Patterns, and Chaos (New York Oxford University Press, 1998) I. R. Epstein, K. Kustin, P. De Kepper, and M. Orban, Scientific American, March 1983, p. 112 and H. Degn, Oscillating Chemical Reactions in Homogeneous Phase, J. Chem. Ed. 1972,49. 302. 

Gray, B. F. and Morley-Buchanan, T., 1985, Some criticism concerning the Brusselator model of an oscillating chemical reaction. J. Chem. Soc. Faraday Trans. 2 81, 77. 

The major characteristics of excitable media, such as oscillating chemical reactions, and some important concepts necessary for understanding their behaviour have been discussed. The capacity of Belousov-Zhabotinsky (BZ) reactions for spontaneous spatiotemporal auto-organization is described 289... 

Very large affinity values may cause instability, and lead to new states that are no larger homogeneous in space. This causes a discontinuous decrease of entropy, and has important consequences in oscillating chemical reactions. Such reactions are far from equilibrium, and present undamped fluctuation on a macroscopic scale. Oscillations around a stationary state are possible as long as the total entropy production is positive. 

The first observation of chemical oscillations was made at the end of the 17th century by Robert Boyle. In the 19th century, several oscillating chemical reactions were discovered, mostly heterogeneous ones. At that time, oscillating chemical reactions did not attract much attention. Chemical kinetics did not yet exist as a branch of science and there was no commonly accepted view of the proper way for a chemical reaction to proceed. 

At approximately the same time, Lotka proposed his famous models of oscillating chemical reactions based on irreversible autocatalytic processes. The first model included one autocatalytic step and gave damped oscillations. The second model became a paradigm in oscillating chemistry. It consists of two consecutive autocatalytic steps, resulting in undamped oscillations. The Lotka models attracted great attention from theoretical biologists, because... 

Many skeptics of oscillating reactions dismisses these classic examples as aberrations due to contamination. Concerns that oscillating reactions could not exist because of apparent violations of thermodynamic laws have recently been refuted by careful studies that establish that oscillating reactions are in accord with thermodynamic laws. Oscillating chemical reactions are unlike the oscillations of a pendulum. Oscillating chemical re-... 

Because a closed system must eventually reach equilibrium, closed systems can sustain oscillating chemical reactions for only a limited time. Sustained oscillating reactions require an open system with a constant influx of reactants, energy and removal of products. 

H. Qian, S. Saffarian, E.L. Elson, Concentration fluctuations in a mesoscopic oscillating chemical reaction system. Proc. Natl. Acad. Sci. USA 99(16), 10376-10381 (2002)... 

Rl) 1972 Degn, H. Oscillating Chemical Reactions in Homogeneous Phase, J. Chem. Education,... 

IIIC) Farage, V. J., Janjic, D. 43. Oscillating Chemical Reactions, III. The Effects of the 1980-2 Temperature and of the Chemical Composition on the Induction Period of the Systems BrOj /Ce(IV)/Cyclohexanone and BrOj" /Ce(IV)/Cyelopentanone, Helvetica Chimia Acta 63,433-437. (Eng.)... 

IIIC) Tikhonova, L. P., Zayats, V. Ya. Study of Oscillating Chemical Reactions with Catalyst,... 

Oscillating Chemical Reactions Involving Macrocyclic Copper Complexes. Dokl. Akad. 

R) Zhabotinskii, A. M. Oscillating Chemical Reactions. Periodic Reactions Based on... 

Oscillating chemical reactions have been known for almost two centuries, i.e., they are as old as chemistry itself. Some involve homogeneous kinetics, i.e., with the participating species either all in solution or all in the vapor phase. More commonly they involve heterogeneous kinetics, such as electrochemical oscillators, of which some were known already to Faraday. Moreover, it is now known that many biological systems incorporate oscillating reactions as clocks, which maintain biologically important rhythms, such as the circadian (approximately daily) cycle. 

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