Transformations of toluene radical cation in ZSM-5 and Silicalite

摘要

Toluene radical cations produced by (gamma) irradiation at 77 K in ZSM-5 and Silicalite (isomorphous with ZSM-5 but nonpolar) undergo a reversible transformation to the norbornadiene radical cation at temperatures (le)150K. The transformation occurs to a greater extent in the more polar zeolite (ZSM-5). The substrate concentration plays an important role. Toluene radical cations undergo ion-molecule reactions to give benzyl radicals at low substrate loading at temperatures >200 K. At higher concentration, different adsorption sites become populated which allow the transformation to norbornadiene radical cation to take place.