Decomposition, radiation induced

Gehringer P, Proksch E, Szinovatz W, et al. 1988. Radiation-induced decomposition of aqueous trichloroethylene solutions. Int J Appl Instrum [A] 39 1227-1231. 

Considerable research has been done in many industrial countries, especially in Japan and in the former U.S.S.R., on the radiation treatment of waste water and other liquid wastes (see Pikaev and Shubin, 1984 Sakumoto and Miyata, 1984). Apart from disinfection or sterilization, the processes involve the radiation treatment of polluted water, the radiation-induced decomposition of dyes, phenols, cyanides, and so forth, (vide supra). At the basis of purification of aqueous waste... 

This effect is not due to deformation impact on hydroperoxide stability rate constants of thermal decomposition of hydroperoxide in PP are the same for both isotropic and deformed samples. Moreover, even at 20°C, when hydroperoxide is stable, its escape during radiation-induced oxidation sharply drops with the growth of X. 

Hydrogen atom abstraction from the 5-methyl group of T produces the 5-(2 -deoxyuridinyl)methyl radical (T(—H) ), which is one of the main reactive radiation-induced decomposition products of As outlined in Scheme 10,... 

Radiation-induced decomposition, 5,6-dihydrothymine, 930 Radiation stress, polymers, 685 Radical polymerization dialkyl peroxides, 707 peroxycarboxylic esters, 697 Radicals... 

For low radiation doses, peroxides accumulate almost linearly with dose. However, after a certain dose has been reached, their concentration tends to level off. This conclusion can be derived from the observed change in the rate of graft copolymerization initiated by polymers subjected to increasing doses of preirradiation in air. Figure 2 illustrates this effect in the case of grafting acrylonitrile onto polyethylene (2). The drop in the yield of peroxide production presumably results from the efficient radiation-induced decomposition of these peroxides. Peroxides are known to decompose under free radical attack, and selective destruction of peroxides under irradiation has been established experimentally (8). This decomposition can become autocatalytic, and sometimes the concentration of peroxides may reach a maximum at a certain dose and decrease on further irradiation. Such an effect was observed in the case of poly (vinyl chloride). Figure 3 shows the influence of preirradiation dose on the grafting ratio obtained with poly (vinyl chlo-... 

The radical polymerization of ethylene, in practice, is initiated by free-radical initiators, although radiation-induced,155 210 photoinduced,211-213 and thermal213,214 initiations are also possible. The temperature of high-pressure polymerization should not exceed 350°C since above this temperature a rapid exothermic (AH = —30.4kcal/mol) thermal decomposition of ethylene can take place leading to a runaway reaction ... 

The introduction of silver ions which act as electron traps enhances the radiation-induced changes in the thermal decomposition of ammonium perchlorate. Irradiated samples containing silver show thermal decomposition similar to samples without silver, but which received a considerably greater radiation dose. 

Anon, Radiation-Induced Solid Propellant Decomposition , RAI-347, Radiation Applications, Inc, Long Island City (1965) (AD-612536)... 

Studies on Radiation-Induced Dislocations and the Decomposition Kinetics of Ammonium Perchlorate , Proc 7th InternSymp on Reactivity of Solids, J.S. Anderson et al, Eds, Chapman Hall, London (1972), 387 212) A.B. Zimmer-... 

In non-polar liquids, then, the evidence seems conclusive that most of the electrons are recaptured by parent ions, at least in the absence of reactive scavengers, and that ionic processes therefore do not contribute significantly to the radiation-induced decomposition. However, in polar liquids where the electron could be solvated, the situation may be quite different. 

Krishnamurthy, M.V., Sampathkumar, R. 1992. Radiation-induced decomposition of the tributyl phosphate-nitric acid system role of nitric acid. J. Radioanal. Nucl. Chem. Lett. 166(5) 421 129. 

ESCA studies on these hexadentate complexes by Lazarus, Hoselton, and Chou191) were not successful. It has been found that the broad satellite structure in the observed 2 p X-ray photoelectron spectra were due to a radiation-induced decomposition of the HS isomer in the spectrometer rather than the result of the multiplet splitting. 

Many groundwaters are contaminated with the cleaning solvents trichloroethylene (TCE) and perchloroethylene (PCE). They are two of the most common organochlorine compounds found in Superfund sites. Radiation-induced decomposition of TCE in aqueous solutions has been the subject of several recent studies [15-20]. In most of the referenced studies, the complete destruction of TCE was observed. Dechlorination by a combination of oxidative and reductive radiolysis was stoichiometric. Gehringer et al. [15] and Proksch et al. [18] have characterized the kinetics and mechanism of OH radical attack on TCE and PCE in y-ray-irradiated aqueous solution. Trichloroethylene was readily decomposed in exponential fashion, with a reported G value of 0.54 pmol J-1. A 10 ppm (76 pM) solution was decontaminated with an absorbed dose of less than 600 Gy. For each OH captured, one C02 molecule, one formic acid molecule and three Cl- ions were generated. These products were created by a series of reactions initiated by OH addition to the unsaturated TCE carbon, which is shown in Eq. (45) ... 

Proksch E, Gehringer P, Szinovatz W, Eschweiler H. Radiation-induced decomposition of small amounts of perchloroethylene in drinking water. Appl Radiat Isot 1987 38 911-919. 

Getoff N, Solar S. Radiation induced decomposition of chlorinated phenols in water. Radiat Phys Chem 1988 31 121-130. 

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