Selective catalytic oxidation of naphthol to 2-hydroxyl-1,4-naphthoquinoneby hydrogen peroxide over metalloporphyrin catalysts

The reactions of 1-naphthol and 2-naphthol were catalytically converted int o 2-hydroxyl-1,4-naphthoquinone (HNQ, lawsone) in the presence of H2O2 over metalloporphyrin catalysts. The catalytic data showed conversion at 57% an d single product of lawsone, which were investigated by UV-Vis, LR, NMR, MS , mp determination, and element analysis. Influences of solvents, amounts o f NaOH, H2O2, and metalloporphyrins, as well as temperature in the catalyti c reaction, were carried out, and a proposed catalytic mechanism based on U V-Vis and EPR measurements was discussed. (C) 2000 Elsevier Science B.V. Al l rights reserved.