Beilstein J. Org. Chem.2006,2, No. 22, doi:10.1186/1860-5397-2-22
Scheme 7 is a possible explanation of this situation but fails to account for reality as no detectable oxygen is observed during the reaction between peroxydisulfate and either 2-quinolone or 2-quinolone-4-carboxylic acid. [16]
An alternative explanation, not strictly catalytic, is shown in Scheme 8