Temperature dependence of the self‐decay rate constants of some phenoxyl radicals in aqueous solution

The Arrhenius parameters of the bimolecular rate constants for the decay of several phenoxyl radicals in aqueous solution were measured. The p‐halophenoxyl radicals (F, Cl, and Br) decay in a diffusion controlled reaction as the activation energies are the same as that of diffusion of water (16 ± 1.5 kJ · mol−1). The A factors are 1012.2 ± 0.2. For alkyl and alkoxy substituted phenoxyl, slightly higher activation energies were found (19.5 − 21.9 kJ · mol−1).