What Contribution can Thermal Theory make to the Study of Hydrocarbon Oxidation

5 What Contribution can Thermal Theory make to the Study of Hydrocarbon Oxidation  

Most of the systems discussed so far show two distinct modes of reaction separated 

The first steps towards an explanation of these extra modes of hydrocarbon oxidation were taken by Frank-Kamenetskii who proposed that the multiple cool flames observed were oscillatory and that the period of oscillation reflected the underlying chemistry. Experimental investigations continued to concentrate upon traditional measurements of pressure versus time, of induction period, and o establishing the identity of stable intermediates and reaction pathways. Interpretations of these results continued to be made on isothermal degenerate branched-chain reactions direct measurements of temperature were not made. These interpretations were very incomplete, and much better understanding has emerged from application of thermokinetic theory. 

Early among the isothermal models used to ex ain periodic cool flames was the Lotka-Volterrascheme invoked - as a possible prototype by Frank-Kamenetskii. Two active intermediates X and Y are postulated in the scheme  

The model has acted as a useful stimulus. It is the only oscillatory model involving not more than two intermediates and having elementary reaction steps with only first- or second-order kinetics, and also satisfying sudi basic diranical reasonableness as non-native concentrations. However, a chemically satisfactory identification of X and Y with species known to be involved has never been attained it is now widely recognized that the conservative oscillations, to which this model in its isothermal form corresponds, cannot be the basis for those actually observed.  

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