Competitive Electron Attachment in Gaseous Halobenzenendash;Benzyl Chloride Mixtures. Evidence for Electron Transfer from the Chlorobenzene Anion to Benzyl Chloride

摘要

The yield of benzyl radicals formed by dissociative electron attachment to benzyl chloride in pulsehyphen;irradiated gaseous cyclohexanendash;benzyl chloride mixtures is reduced by the addition of halobenzenes. The results are interpreted in terms of competitive electron scavenging by the halobenzenes and the ratio of the rate constants,kC6H5Xthinsp;sol;thinsp;kBZCl, for electron attachment at 120deg;C is found to be 20, 0.9, 0.6, and le;thinsp;0.005, for iodohyphen;, bromohyphen;, chlorohyphen;, and fluorobenzene, respectively. In the case of chlorobenzene, the data do not obey simple competition kinetics. This is explained in terms of the formation of a chlorobenzene anion which subsequently undergoes electron transfer to benzyl chloride in competition with ion recombination. The rate constant for electron transfer is estimated to be5thinsp;times;thinsp;10minus;11cm3sol;sec.