A comparative mechanistic study of the oxidation of phenols in aqueous solution by oxomanganese(IV) and oxoiron(IV) 5,10,15,20-tetrakis(2-N-methylpyridyl)porphyrin

作者：Kamp NWJ; Smith JRL

来源：Journal of Molecular Catalysis A: Chemical , 1996, 113(1-2): 131-145.

DOI：10.1016/S1381-1169(96)00057-X

• Hammett equations
• monopersulphate
• oxidation
• iron
• manganese
• oxo complexes
• peroxidase
• phenol
• porphyrin

The kinetics of the reactions of phenol and six substituted phenols with oxomanganese(IV) tetra(2-N-methylpyridyl)porphyrin in aqueous solution (pH 7.7) have been studied. The reactions are shown to be first order in both phenol and the oxomanganese(IV) species. The second order rate constants have been measured and the influence of the substituents on these values have been analyzed using Hammett and modified Hammett equations. The magnitude of the rho values obtained and the good correlation of the data with sigma(.) and the dual parameter sigma(.) + sigma(+) suggest that, like the reactions of the analogous oxoiron(IV) tetra(2-N-methylpyridyl)porphyrin, the rate-determining step in these oxidations involves hydrogen atom abstraction from the phenol by the oxomanganese(IV) species in which the transition state has partial charge separation.

• 出版日期1996-11-25