SOLVENT EFFECT ON THE RATE OF BETA-SCISSION OF THE TERT-BUTOXYL RADICAL

The transient absorption spectrum of the tert-butoxyl radical in the U V region was obtained by the laser flash photolysis technique. The rat e constants for beta-scission and self-termination reactions of tert-b utoxyl radicals were measured in five solvents; the Arrhenius paramete rs of the rate constant for beta-scission k(beta) were determined. It was shown that both the solvent polarity and ability for hydrogen bond ing accelerate the reaction of beta-scission. The solvent effect on th e rate constant of the p-scission reaction is discussed in terms of a simple Onzager-Betcher model, a point dipole model, and a model of the H-bonded complex of the radical with the solvent molecule.