Free Radicals as Stabilizers

In connection with this problem, we undertook an attempt to use radicals produced by replacing the active amine hydrogen with an oxygen atom according to the scheme-. 

These radicals are comparatively stable and are good antioxidants of polypropylene and a number of liquid hydrocarbons. 

The fact that the azotoxide radical, produced by the oxidation of diphenylamine, is itself an antioxidant was noted by Thomas, who compared the inhibition of the oxidation of white oil by additives of small amounts of diphenylamine and diphenylazotoxide [82]. 

Likhtenshtein [83] has shown that diphenylazotoxide is consumed very slowly during the induction period of the oxidation of cetane at 150 C, apparently at a rate equal to the rate of initiation. Only at the end of the induction period does the rate of consumption of diphenylazotoxide increase (Fig. 29). 

A number of aliphatic azotoxides [84], the structural formulas of which are cited below, have also been synthesized from triacetone-amine I  

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