ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Investigations on the Chain Length Dependence of Radical Reactivity

A. Behazadi, U. Borgwardt, and W. Schnabel

Hahn — Meitner-Institut für Kernforschung Berlin GmbH, Sektor Strahlenchemie, 1 Berlin 39

Abstract: The rate constant of the reaction scavenger S with radical R. in aqueous solutions has been determined as a function of the size of the radical. Scavengers were tetranitromethane (TNM) and p-nitrosodimethylaniline (PNDA). The radicals were produced by hydrogen atom abstraction from ethylene oxide oligomers and polymers. I t was found that in both cases k_R+S is proportional to the diffusion coefficient of the radical R», but it could be demonstrated that the reaction R. + PNDA is not encounter-controlled. The reaction R. + TNM is almost encounter-controlled. Its chain length independence at long chain length leads to the conclusion that the reaction is essentially determined by the diffusion of the scavenger and that the diffusion of the latter is not hindered within the coil of a macromolecule.

Full paper in Portable Document Format: 263a242.pdf

Chemical Papers 26 (3) 242–249 (1972)