The Far Ultraviolet Photolysis of Alkenes: The Use of Hydrogen Sulfide as a Radical Scavenger

Abstract

The far u.v. photolysis of cis-2-butene, n-1-pentene, and cis-2-pentene was carried out in the presence of various quantities of hydrogen sulfide. We showed that in these systems, hydrogen atoms add to the double bond and are not scavenged by 5–10% hydrogen sulfide. On the other hand, alkyl radicals such as methyl, ethyl, s-butyl, and s-pentyl react with hydrogen sulfide, and the formation of the corresponding alkanes may be used to measure the absolute yields of the radical species. The same holds true for vinyl radicals. We also report some experiments published elsewhere. In particular, in the case of 1,3-butadiene, identification of the principal radicals is possible; however, measurement of absolute yields becomes more difficult.