Oxidation of 2,6-Di-tert-butylphenol by Molecular Oxygen. 2. Catalysis by Cobaltous Polyamine Chelates through Their (μ-Peroxo)- and (μ-Peroxo)(μ-hydroxo)dicobalt(III) Complexes

Article abstract of DOI:10.1021/ja00312a018

The oxidation of 2,6-di-tert-butylphenol by molecular oxygen is catalyzed by the cobaltous chelates of tetraethylenepentamine (TETREN), dipicolyldiethylenetriamine (PYDIEN), and 1,4,10,13-tetraaza-7-thiatridecane (TATTD), through their (μ-peroxo)dicobalt(III) complexes and by those of dipicolylethylenediamine (PYEN), tris(aminoethyl)amine (TREN), and triethylenetetramine (TRIEN) through their (μ-hydroxo)(μ-peroxo)dicobalt(III) complexes.Reaction products are identified as the oxidative coupling product 3,3'5,5'-tetra-tert-butyldiphenoquinone and the partial oxygen insertion product, 2,6-di-tert-butylbenzoquinone.The rates of reaction of the substrate as well as the formation of products are shown to be first order with respect to the concentrations of both the cobalt-dioxygen complex and the substrate.The reaction with (4+) does not occur in the absence of free molecular oxygen in solution and occurs at a reduced rate under air relative to oxygen.