Chemical Turbulence : Belousov Zhabotinsky reaction Typically…

Chemical Turbulence : Belousov Zhabotinsky reaction

Typically one thinks about chemical reactions as walking down a straight path from home to destination.

A + B —-> C ( A reacts with B to give C). 

But this necessarily need not be true:

In a class of reactions known as Belousov–Zhabotinsky reaction, or BZ reaction. the reactions undergo a chaotic oscillating behavior for a substantial amount of time before they end up at the final product C .

Oxidation waves

It was observed in 1970 by Zaikin and Zhabotinsky that by using a thin
layer of unstirred solution with the ferroin-catalyzed BZ
reaction one could observe periodic propagation of
concentric chemical waves from point sources.

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The Belousov-Zhabotinsky oscillator reaction is known for the striking oxidation
waves that it produces.

In the above animation you can see symmetrical circular wave fronts being generated, but when the concentration parameters are tweaked it is possible to observe spiral waves as well.

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And when one propagating wave meets another, they mutually annihilate each other.

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One important note concerning this reaction is that this chaotic oscillating behavior that one observes does not last forever and dies out eventually.       

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                                     Source Video by nater06      

Another reaction that is analogous to the BZ reaction is the Briggs–Rauscher reaction (see below)

Simulating the BZ reaction

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Some of the  essential features of this reaction can be captured in a simple reaction model
involving three chemical substrate.

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The simulations are able to go so far as to predict the spirals and waves that one observes during the reaction.

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But the complete model for this nonlinear chemical oscillator is not entirely known and still remains a mystery..

References:

[1] The Belousov-Zhabotinsky Oscillator: An overview

[2] Ways in which the BZ reaction is studied

[3] Belousov-Zhabotinsky reaction on Scholarpedia

[4] A simple model of the BZ reaction from first principles.