UV-Stimulated HT Oxidation in Oxygen Atmosphere

Hasegawa, Kiyoshi; Fusumae, H.; Matsuyama, Masao; Watanabe, Kuniaki

doi:10.13182/fst92-a29796

Cited by 2 publications

(3 citation statements)

References 15 publications

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“…The characteristic features of this figure are: 1) the concentration of TCI HT oxidation [7][8][9]. Namely, there was no autocatalytic feature.…”

Section: Resultsmentioning

confidence: 92%

“…With respect to the extraordinarily fast reaction rate and the abnormal feature of the reaction curve, the formation of HC1 (TCI) appeared to be responsible, because its formation was predicted by inspection of the elementary reactions relevant to the UV-stimulated HT oxidation [8,[14][15][16][17][18] and to the photochemical reactions between CFCs and ozone responsible for the destruction of stratospheric ozone [10,11,14,15,[19][20][21][22] (Table 1). To examine this assumption, the hydrogen-ion concentration in water in the first bubbler was measured using a pH meter during the reaction.…”

Section: Resultsmentioning

confidence: 99%

“…This phenomenon was designated as the UV-stimulated HT oxidation [8,9], The rate of HTO formation in the UV-stimulated reaction is proportional to the pressure of O 2 , molar fraction of HT with respect to total hydrogen pressure (H 2 +HT), and square root of the total pressure [8]. A computer simulation consisting of 30 elementary reactions gives the same pressure and molar fraction dependence as the observed one [8,9]. It indicates that the UV-stimulated reaction is initiated by the photolysis of O 2 to produce O( 3 P), and subsequent formation of O 3 and OH(OT) plays an important role.…”

Section: Introductionmentioning

confidence: 99%

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Acceleration of the UV‐stimulated HT oxidation by CCl₄

Hasegawa

Fusumae

Miyahara

et al. 1994

Journal of Environmental Science and Health . Part A: Environme

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The effects of air pollutants on UV-stimulated HT oxidation were studied by selecting CCl 4 as a model pollutant. Mixture gases consisting of H 2 +HT, O 2 and CCl 4 were irradiated with a high pressure mercury lamp. The reaction products were found to be HTO and TCl. The role of CCl 4 was evaluated by measuring the formation rate of HTO+TCl as a function of the partial pressure of CCl 4 . The reaction took place in two stages. During the first stage, the extent of the reaction increased almost linearly with time. During the second stage, the rate became faster with time, showing a similar feature to 282 HASEGAWA ET AL.autocatalytic reactions. It was found that those rates were considerably increased with the pressure of CCl 4 . In the case of 1.0 Torr, the rate of the first stage was 60 times greater than that of the UV-stimulated HT oxidation previously reported, and that of the second stage was about 10 times that of the first stage. As a whole, the CCl 4 -assisted UV-stimulated HT oxidation showed a 5×10 4 -5×10 5 times greater reaction rate than the ß ray-induced radiochemical HT oxidation. With the aid of computer simulation including 47 relevant elementary reactions, the enhanced acceleration of the reaction was understood as a result of the formation of new reaction paths such as Cl H HO 2 H 2 O and Cl H HO 2 OH H 2 O, which lacked in the UV-stimulated HT oxidation mechanism.

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“…The characteristic features of this figure are: 1) the concentration of TCI HT oxidation [7][8][9]. Namely, there was no autocatalytic feature.…”

Section: Resultsmentioning

confidence: 92%