Iodine as a radical scavenger in the radiolysis of cyclopentane

Abstract

Scavenging techniques with iodine in the concentration range of 0.1 to 30 mM were used to elucidate the radical yields in the γ-radiolysis of cyclopentane. In solutions below about 1 mM iodine reacts solely with alkyl radicals in the bulk of the medium. However, above this concentration the scavenging of thermal hydrogen atoms becomes significant and virtually all of the hydrogen atoms are scavenged at an iodine concentration of 30 mM. High concentrations of iodine are also found to reduce the cyclopentene yield, probably by reaction with ionic species produced as intermediates in cyclopentane radiolysis. At low iodine concentrations the yield of the main scavenging product, cyclopentyl iodide, and thereby the yield of the scavenged cyclopentyl radicals that escape the spur into the bulk medium was found to be 4.0 radicals/100 eV. The total cyclopentyl radical yield derived from the observed k d/ k c ratio and the bicyclopentyl yield is estimated to be 4.9 radicals/100 eV.