Rate constants for the reactions of free radicals with oxygen in solution

Abstract

The kinetics of the reactions of several free radicals with oxygen have been examined in solution at 300 K using laser flash photolysis techniques. The reactions of resonance-stabilized radicals are only slightly slower than those of nonstabilized radicals: for example, for tert-butyl (in cyclohexane), 4.93 × 109; benzyl, 2.36 × 109 (in cyclohexane); cyclohexadienyl (in benzene), 1.64 × 109 M-1 s-1. The reaction of n-Bu3Sn• radicals is unusually fast (7.5 × 109 M-1 s-), a fact that has been tentatively attributed to a relaxation of spin selection rules due to heavy atom effects. © 1983 American Chemical Society.