The largest body of literature on solvent effects on reaction rates is in bimolecular hydrogen abstraction reactions. Nearly four decades ago, Das et al. used laser flash photolysis to study the reaction of tert-butoxyl radicals with phenols in six solvents . The rate decreased in polar solvents, explained by the capability of the phenolic OH group to hydrogen bond with solvent molecules. Ingold and co-workers have attempted since to further deduce these solvent effects in hydrogen abstraction reactions. Valgimigli et al. found that the solvent effect on abstraction of the phenolic hydrogen from α-tocopherol by both tert-butoxyl radical and 2,2,-diphenyl-1-picrylhydrazyl (DPPH•) is independent of the radical in almost every solvent they tested (see Figure ). This result is especially surprising, since for these two radicals, the reaction rate in the same solvent differs by over 10 6 . Any deviation from this behavior, as in tert-butyl alcohol, is thought to be due to the reaction being partially diffusion controlled. The reaction of α-tocopherol with tertbutoxyl was further investigated in four solvents; the rate constant decreased with increasing β H 2 value , a measure of solvent basicity. In solvents with both high dielectric constant and basicity, different behavior is observed, discovered in a study of the reaction between Trolox and 2.0 )