Free Radicals from the Flash Photolysis of Phenol

1960 ◽  
Vol 32 (1) ◽  
pp. 305-306 ◽  
Author(s):  
L. I. Grossweiner ◽  
E. F. Zwicker
Keyword(s):  
Free Radicals ◽  
Flash Photolysis ◽  
Photolysis Of Phenol

Flash-photolysis electron spin resonance in solution studies of free radicals

1984 ◽  
Vol 78 ◽  
pp. 257 ◽  
Author(s):  
Christopher D. Buckley ◽  
Andrew I. Grant ◽  
Keith A. McLauchlan ◽  
Andrew J. D. Ritchie
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Flash Photolysis ◽  
Solution Studies ◽  
Spin Resonance

Quantum Yields for the Photodegradation of Pollutants in Dilute Aqueous Solution: Phenol, 4-Chlorophenol and N-Nitrosodimethylamine

1996 ◽  
Vol 1 (2) ◽  
Author(s):  
Te-Fu L. Ho ◽  
James R. Bolton ◽  
Ewa Lipczynska-Kochany
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Quantum Yield ◽  
High Performance ◽  
Flash Photolysis ◽  
Quantum Yields ◽  
Visible Absorption ◽  
Dilute Aqueous Solution ◽  
Uv Visible ◽  
Photolysis Of Phenol

AbstractA broadband method has been applied to determine the quantum yields for the photochemical removal of three common pollutants: phenol, 4-chlorophenol and N-nitrosodimethylamine (NDMA) in dilute aqueous solution. Flash photolysis (xenon flash lamps) was used to cause a significant amount of photolysis without photolyzing intermediates. The analysis of reactant depletion following a single flash was carried out by high- performance liquid chromatography (HPLC) or UV/visible absorption spectroscopy. The method for determining quantum-yields employed p-benzoquinone as an actinometer and was validated by determining the average (200-400 nm) quantum yield for the generation of hydroxyl radicals from the photolysis of hydrogen peroxide (0.90 ± 0.10) and the quantum yields for the photolysis of phenol (0.13 ± 0.02) and 4-chlorophenol (0.24 ± 0.04). The values determined agree very well with the literature ones obtained with monochromatic radiation. The quantum yield for the direct photolysis of NDMA was found to be 0.11 ± 0.03 at neutral pH and 0.27 ± 0.02 at pH 2-4. Under conditions where hydrogen peroxide is the principal absorber, the NDMA quantum yield is 0.32 ± 0.04, independent of pH in the range 2-8.

Thiophosphonyl Radicals Photolytic Generation and Reactivity Towards Olefinic Compounds

1985 ◽  
Vol 40 (6) ◽  
pp. 541-543 ◽  
Author(s):  
T. Sumiyoshi ◽  
W. Weber ◽  
W. Schnabel
Keyword(s):  
Absorption Spectrum ◽  
Free Radicals ◽  
Optical Absorption ◽  
Vinyl Acetate ◽  
Optical Absorption Spectrum ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Uv Light ◽  
Strong Band

Upon irradiation with UV light (λ = 347 nm), 2,4,6-trimethylbenzoyldiphenylphosphine sulfide was found to be fragmented into free radicals by α-scission (F(k) = 0.3 ± 0.1): Flash photolysis studies revealed that the optical absorption spectrum of diphenylthiophosphonyl radicals, S = P(Ph)2. possesses a strong band with λmax = 340 nm and a somewhat weaker band with λmax ≈ 500 nm (e340nm = 1.2 ± 0.2) · 104 1/mol cm). The reactivity towards olefinic compounds, M, is 10 to 30 times lower than in the case of O = P(Ph)2 radicals. Typical bimolecular rate constants (in 1/mol s) of the reaction of S = P(Ph)2 with M are: 4 x 106 (styrene), 6.2 x 105 (methylacrylate), 4.2 x 104 (vinyl acetate).

scholarly journals Identification of Free Radicals in Flash Photolysis

Nature ◽  
1964 ◽  
Vol 204 (4962) ◽  
pp. 988-988 ◽  
Author(s):  
G. HERZBERG ◽  
D. N. TRAVIS
Keyword(s):  
Free Radicals ◽  
Flash Photolysis
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