Mechanism of bleaching by peroxides

Kinetics and mechanisms of the bleaching of methyl orange by H2O2 catalysed by MoO42− and WO42− have been studied from pH 8.95 to 11.0 in a variety of buffers. Contributory rate constants for both the peroxometalate catalyst and the singlet oxygen pathways were determined from experiments both without and with the singlet oxygen trap 2,5-dimethylfuran. The variation with pH of the singlet oxygen rate constants correlated well with 1O2 generation rates in the literature.