Pulse radiolysis studies of the oxidation of phenols by. SO/sub 4//sup -/ and Br/sub 2//sup -/ in aqueous solutions
The reactions of SO/sub 4//sup -/ and Br/sub 2//sup -/ with phenol, o-, m-, and p-cresol, and tyrosine have been studied by pulse radiolysis methods using optical absorption and conductometric detectors. The reaction of SO/sub 4//sup -/ with the undissociated phenols was found to be very rapid; in the case of tyrosine the rate constant was measured to be (3.0 +- 0.2) x 10/sup 9/ M/sup -1/ sec/sup -1/. With tyrosine, formation of the phenoxyl radical was shown to be complementary to the disappearance of SO/sub 4//sup -/ with no intermediate having a lifetime greater than 0.1 ..mu..sec being possible. Thus, the reaction proceeds most probably by a direct oxidative electron transfer from the phenol. Reaction of Br/sub 2//sup -/ with the phenoxide ions gave similar spectra. Calculated extinction coefficients based on reaction of Br/sub 2//sup -/ and SO/sub 4//sup -/ agreed to within the experimental error of +-5 percent. Conductometric experiments (SO/sub 4//sup -/ reaction) showed identical behavior for all phenols in near neutral solution with exactly the same yield of strong acid produced as when SO/sub 4//sup -/ abstracts from CH/sub 3/OH. Thus quantitative direct oxidation to a phenoxyl radical must occur in each case.
- Research Organization:
- Carnegie-Mellon Univ., Pittsburgh
- OSTI ID:
- 7343074
- Journal Information:
- Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 67:1; ISSN RAREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AQUEOUS SOLUTIONS
AROMATICS
BIOCHEMICAL REACTION KINETICS
BROMINE COMPOUNDS
CATIONS
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DISPERSIONS
ELECTRON TRANSFER
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
HALOGEN COMPOUNDS
HYDROXY COMPOUNDS
IONS
IRRADIATION
KINETICS
LEPTONS
MIXTURES
ORGANIC COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PHENOLS
PULSED IRRADIATION
RADIATION CHEMISTRY
RADIATION EFFECTS
RADICALS
RADIOLYSIS
REACTION KINETICS
SOLUTIONS
SULFATES
SULFUR COMPOUNDS