Pulse radiolysis studies on reaction of triacetoneamine-N-oxyl with radiation-induced free radicals

Abstract

Absolute rate constants for the reactions of the stable free radical triacetoneamine-N-oxyl (TAN) with a variety of radiation-induced radicals have been determined by direct observation or by competition methods. Like oxygen, TAN reacts rapidly with the electron adducts of acetophenone, thymine and nicotinamide adenine dinucleotide (k= 10⁸-10⁹ M^–1 s^–1) and reacts slowly, if at all, with the electron adducts of p-nitroacetophenone and benzoquinone. Absolute rate constants for the reaction of TAN with neutral aliphatic radicals are, in general, an order of magnitude lower than the analogous reactions with oxygen. Unlike oxygen, TAN also reacts with halide radical anions, X^– ₂ at near diffusion-controlled rates.