Pulse radiolysis of sulphur compounds. Part 2.—Free radical “repair” by hydrogen transfer from sulphydryl compounds

Abstract

The intense transient absorption spectrum of the radical-anion RSSR^– produced in the pulse radiolysis of cysteamine solutions NH₂CH₂CH₂SH, (RSH) by the reaction RS + RS^–⇌RSSR^– has been used to observe and measure the kinetics of hydrogen transfer reactions from the sulphydryl group to a number of simple organic radicals. This radical repair process is first order in cysteamine concentration and depends upon the dissociation constants of the SH group. In oxygenated solutions containing methanol, oxygen competes with cysteamine for the radical. CH₂OH. Rate data are presented and the mechanisms discussed.