Selective oxidation of primary substituted aromatic amines to azoxy products using lacunary catalyses

Some of the substituted anilines were selectively converted in to the corresponding azoxy and azobenzenes by oxidation with 30% aqueous hydrogen peroxide. The reactions were catalyzed by various heteropolyoxometalates, at boiling point of the used solvents. An improvement in the product yield and selectivity towards azoxybenzens was also observed. Azobenzenes was obtained as by-product. In the all similar cases, the highest yield of azoxy compounds was observed using K5PW11ZnO39 as catalyst in N,N-dimethylformamide solvent.