Photolysis of hydrogen peroxide

Hambly, D.M. Gross, M.L. Laser flash photolysis of hydrogen peroxide to oxidize protein solvent-accessible residues on the microsecond timescale. J. Am. Soc. Mass Spectrom. 

The stoichiometric yield of OH0 is the greatest from the photolysis of hydrogen peroxide. But - as already mentioned - the photolysis of ozone yields more OH0 than that from hydrogen peroxide because of the higher molar extinction coefficient of ozone compared to hydrogen peroxide (see Table 2-3). 

Baxendale, J.H. and Wilson, J.A., The photolysis of hydrogen peroxide at high light intensity, Trans. Faraday Soc., 53, 344-356, 1957. 

Stefan, M.I., Hoy, A.R., and Bolton, J.R., Kinetics and mechanism of the degradation and mineralization of acetone in dilute aqueous solution sensitized by the UV photolysis of hydrogen peroxide, Environ. Sci. Technol., 30, 2382-2390, 1996. 

Reactions of ozone can be initiated by HO or HOO or by photolysis of hydrogen peroxide. Ozone can also be decomposed through the following reaction pathways ... 

Photolysis of hydrogen peroxide was first studied by Baxendale and Wilson [99]. They reported that the decomposition of 1 mol of hydrogen peroxide needed one Einstein of incident 254 nm UV radiation ... 

Baxendale JH, Wilson JA. Photolysis of hydrogen peroxide at high light intensities. Trans Faraday Soc 1957 53 344-356. 

Figure 3. Effect of MWCNT on a) amount of hydroxyl radicals generated by photolysis of hydrogen peroxide, measured by ESR/spin trapping technique b) amount of superoxide radicals generated by a xantine/xantine oxidase system, measured by UV spectroscopy. Light gray bars no NT, dark gray bars in the presence of NT.31...

Photolysis of Hydrogen Peroxide - A Direct Source of Hydroxyl Radical. . 108... 

Nitrate photolysis is a relevant source of hydroxyl in natural waters. A study carried out on the Greifensee Lake water indicates that nitrate photolysis is a much more important source of hydroxyl when compared with the photolysis of hydrogen peroxide or the Fenton reaction [12]. Nitrate photochemistry can thus lead to a steady-state hydroxyl concentration around 5 x 10 16 M [8]. 

Fenton type reactions are particularly important in atmospheric waters [10], which are acidic. An additional source of hydroxyl radical that is significant only when using UV light of wavelength shorter than about 300 nm (i.e. in the case of water treatment using UV lamps, but not for sunlight) is represented by photolysis of hydrogen peroxide ... 

Other peroxygen species can also be photolytically cleaved to yield the hydroxyl radical and another radical centre. For example, homolysis of peroxymonosulfate (HOOSO3) generates OH and SO4-. The concentration of the generated hydroxyl radical can be controlled by variation of the wavelength and the intensity used. The photolysis of hydrogen peroxide in the presence of alcohol produces EPR (electron paramagnetic resonance) spectra which indi-... 

Stefan MI, Hoy AR, Bolton JR (1996) Kinetics and Mechanism of the Degradation and Mineralization of Acetone in Dilute Aqueous Solution Sensitized by the UV Photolysis of Hydrogen Peroxide, Environ. Sci. Technol. 30, No. 7 2382-2390. 

Free radicals can be formed by thermolytic cleavage, photolysis (nltravi-olet light photolysis of hydrogen peroxide to form hydroxyl radicals), radiolysis (ionizing radiation of water to form hydroxyl radicals), or by homolytic cleavage with the participation of another molecule (i.e., Fenton reaction). Perkins, J., Radical Chemistry The Eundamentals, Oxford University Press, Oxford, UK, 2000. 

Hydroxyl radicals generated by photolysis of hydrogen peroxide have been used to oxidize ethanol by abstraction of hydrogen from Kinetics have... 

In addition to the photoelectrochemical (catalysed by Ti02) mechanism discussed above, also the chemical and photochemical mechanisms of H2O2 decomposition are to be considered. In strongly irradiated, alkaline solutions the direct photolysis of hydrogen peroxide (strictly speaking-of HO2 ions) should seriously be taken into account for the... 

Radiolysis of oxygenated water or photolysis of hydrogen peroxide solutions yields two oxidative species, the -OH radical and the perhy-droxyl radical (HO2 02" + H ). As previously discussed, the final reaction product of hydroxyl radicals interaction with ascorbate above pH 6 is predominantly the ascorbate anion radical (A ). To account for the stoichiometry of ascorbic acid consumption in a Co gamma ray study of oxygenated ascorbic acid solutions, the ascorbic acid free radical was thought (3) to react with molecular oxygen to yield a transient adduct ... 

The oxidation of ascorbic acid/ascorbate by H02/02 radicals was studied (27) in the pH range 2.75-7.78. The H02/02 radicals were generated by flash photolysis of hydrogen peroxide in presence of ascorbic acid/ascorbate ... 

Secondary radicals may be formed by reaction between primary radicals and solvent. Thus hydroxyl radicals are produced by the photolysis of hydrogen peroxide in an isopropanol glass . At 110° K a seven-line spectrum, with intensities of 1 6 15 20 15 6 1, was observed. Such a structure is to be expected from an unpaired electron which interacts equally with six protons, and since it is known that there is no interaction with the proton of the -OH group in alcohol radicals, the spectrum suggests that the radical is (CH3)2COH. 

There was a strong possibility that initiation occurred via photosensitized formation of hydrogen peroxide on the metal oxide surface followed by desorption and subsequent photolysis of hydrogen peroxide to form free radicals. Radicals formed by this means would lead to abstraction of hydrogen from the fiber surface and subsequent grafting of poly(methyl acrylate) at these sites. 

The rate coefficients for the gas-phase reaction of OH radicals with dimethyl sulphide were determined using a relative rate method. The kinetic experiments were performed at a total pressure of 1000 mbar diluent gas (N2, synthetic air, or N2/O2 mixtmes), at three different O2 partial pressure ( 0 mbar, 205 mbar, and 500 mbar) and six different temperatures (250 K, 260 K, 270 K, 280 K, 290 K, and 299 K). The photolysis of hydrogen peroxide (H2O2) was used as the OH radical source ... 

The hydroxy radical, which can be formed either by the photolysis of hydrogen peroxide and per-acid, by Reaction 5, or by non-terminating... 

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