Oxidation of ketones with ozone

Oxidation of methyl ethyl ketone with a mixture of oxygen and ozone in CC14 at 20—50° C yields acetic acid, diacetyl (intermediate) and hydrogen peroxide [280]. The reaction is second order with a rate coefficient, k = 3.6 X 109 exp(—17,000/RT) 1 mole 1 s 1. The oxidation of the ketone under these conditions is a radical non-chain reaction. Peroxy radicals react faster by a termination reaction than by a propagation reaction at these temperatures. In aqueous solution, ozone oxidizes the ketone as well as the enol form of methyl ethyl ketone [281] and therefore acid accelerates the rate of oxidation. 

Information has been obtained recently [282] on the oxidation of methyl ethyl ketone with ozone at low oxygen concentrations. The reaction rate was found to increase with decreasing concentration of oxygen in the ozone. The rate of ketone oxidation depended on [02] and [03] according to 

This result is explained by a chain reaction with an elementary propagation step R- + 03 - RO + 02, viz. 

W = fcJRH] [03] + 2feofe1fe21e[RH][03]2[02]-1 and agrees with the experimental expression with k = 2kakl fej e.  

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