An air oxidation reaction is an oxidation in which molecular oxygen supplied as air functions as the terminal oxidant for an organic substrate. The substrate transfers reducing equivalents to O2 either directly or, more commonly, through a catalyst and redox mediator that cycle between oxidation states [1]. Depending on the mechanism, oxygen may be incorporated into the product or reduced to water or hydrogen peroxide while another reagent supplies the product oxygen atom. Catalytic aerobic alcohol oxidation, for example, couples substrate dehydrogenation to O2 reduction through metal and organic redox cycles [2]. The defining criterion is consumption of atmospheric oxygen as the stoichiometric electron acceptor; a reaction merely conducted in an open flask but oxidized by an unrelated reagent is not air oxidation. Autoxidation through radical chains and controlled catalytic aerobic oxidation both belong to the class, but they differ in initiation, propagation, selectivity, and the identity of oxygen-derived intermediates such as peroxyl radicals or metal–oxygen species.
Catalysis and Oxidation Reactions • Catalysis • Chemical Engineering • Physical Sciences