Can. J. Chem. 54, 275 (1976). It is shown that e,,,,, He, and OH formed by the radiolysis of water by 3 MeV electrons are trapped by nitroso and nitrone compounds to give nitroxides with well defined esr spectra. Three spin trapping agents were used, nitroso-t-butane, phenyl-t-butyl nitrone, and 5,s'-dimethyl pyrroline-I-oxide. The latter was shown to be an excellent con~pound for these studies. Complications due to the instability of some of the nitroxides were overcome by coupling the electron accelerator to the esr spectron~eter to permit direct observation of the spectra. On a montrC que les e,,,,,, Ha, et OH formts par radiolyse de I'eau par des Clectrons B 3 MeV sont captCs par des composes nitroso et nitrone et conduisent B des nitroxydes avec des spectres rpe bien dtfinis. On a utilise trois agents de piCgeage; L e nitroso t-butane, la phtnyl t-butyl nitrone et la dimethyl-5,5' pyrroline oxyde-I. On a n~o n t r i que ce dernier composC est excellent pour ces ttudes. On a CliminC les con~plications dues a I'instabilitC de q~~elques nitroxydes en couplant directement I'acctICrateur d'Clectron au spectromktre de rpe pour permettre une observation directe du spectre.[Traduit par le journal]

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FREDERICK PETER SARGEKT and EDWARD M~CHAEL CARDY. Can. J. Chem. 52,3645 (1974). The radicals produced during y radiolysis of methanol, ethanol, I-propanol, 2-propanol, and t-butanol have been trapped by reaction with 2-nitroso-2-niethylpropane (t-nitrosobutane) to give nitroxides which are detected by e.s.r.All the alcohols gave alkoxy radicals and, with the exception of t-butanol, radicals derived by the loss of an H atom from the carbon atom adjacent to the OH group. Methyl radicals were detected in t-butanol.FREDERICK PETER SARGENT et EDWARD MICHAEL GARDY. Can. J. Chem. 52,3645 (1974). On a piege les radicaux produits loss de la radiolyse gamma du methanol, de l'ethanol, du propanol-I, du propanol-2, et du rerr-butanol avec du nitroso-2 methyle-2 propane (rerr-nitrosobutane) qui conduisent a des radicaux nitroxydes q~~i peuvent Etre detectes par r.p.e. R . + t-BuNO + t-BUN-R

FREDERICK PETER SARGENT, MARSHALL GRANT BAILEY, and EDWARD MICHAEL GARDY. Can. J. Chern. 52, 2171 (1974).A comparison of both the e.s.r. spectra and the thermal stability of the radicals produced in y radiolysis and 185 nm photolysis of acetonitrile shows that the former are not free methyl radicals. The initial species formed by y radiolysis can be converted by photobleaching into a methyl radical weakly associated with a cyanide ion. The methyl radical of this CH3---CNpair decays via hydrogen abstraction, whereas the free methyl radicals produced by 185 n m photolysis of acetonitrile are quite stable at 77 K. We ascribe the low energy of activation for the hydrogen abstraction reaction in the y irradiated samples not primarily to quantum mechanical tunnelling but to perturbation by the cyanide ion.

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