Variable-temperature EPR was used to investigate reactions of olefin r
adical cations generated radiolytically in nonacidic and acidic ZSM-5
zeolites. The olefin radical cations undergo isomerization reactions e
ven at 4 K. Radical cation reactions are presumably driven by the exot
hermicity of charge transfer, which is not efficiently quenched by the
vibrational modes of the zeolite lattice. The observation of H-additi
on type radicals indicates Bronsted acid-catalyzed rearrangements prio
r to irradiation on the more acidic zeolites.