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), Vol. 67:1; Conference: 23. Radiation Research Society meeting, Miami Beach, FL, USA, 11 May 1975
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BROMINE COMPOUNDS
BIOCHEMICAL REACTION KINETICS
PHENOLS
RADIOLYSIS
SULFATES
AQUEOUS SOLUTIONS
CATIONS
ELECTRON TRANSFER
ELECTRONS
OXIDATION
PULSED IRRADIATION
RADICALS
AROMATICS
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DISPERSIONS
ELEMENTARY PARTICLES
FERMIONS
HALOGEN COMPOUNDS
HYDROXY COMPOUNDS
IONS
IRRADIATION
KINETICS
LEPTONS
MIXTURES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
REACTION KINETICS
SOLUTIONS
SULFUR COMPOUNDS
560111* - Radiation Effects on Biochemicals- In Vitro- (-1987)