The conversion of metal catalysts into inhibitors of autoxidation

It is demonstrated that certain cobalt compounds which are autoxidation catalysts at low concentrations become inhibitors at higher concentrations. In all these cases inhibition implies a lengthening of the induction period, but only in a few systems (N‐alkylamide + cobaltous acetate) is the inhibitory effect observable beyond the induction period. In the case of hydrocarbons and cobalt(II) salicylaldimines the rate of oxygen uptake beyond the substantially increased induction period is not reduced even at the highest catalyst concentrations. A reaction mechanism and a kinetic scheme, consistent with the novel experimental observations, are proposed.