Relative reactivities of substituted phenyl radicals in elementary reactions

Abstract

The relative reactivities of phenyl, p-chlorophenyl, and p-nitrophenyl radicals, derived from arylazotriphenyl-methane, towards chlorine abstraction from carbon tetrachloride were estimated from the results of the competitive reaction of the radicals with carbon tetrachloride and iodine, assuming that the rate of scavenging of the radicals by iodine is almost invariant, irrespective of the substituent on the radical. On the basis of the results, the relative reactivities of these radicals in other elementary reactions such as hydrogen abstraction, bromine abstraction, addition to benzene or allyl sulphide, and S_H2 displacement on disulphide were estimated. These data show that p-chloro- and p-nitro-phenyl radicals are more reactive than phenyl towards electron-donating substrates and less reactive towards elecron-accepting substrates.