Neutral radicals are observed at 77 K following radiolysis of cyclohep
tatriene and cyclohexane adsorbed on ZSM-5 zeolites. The mechanism of
radical formation is assigned to proton transfer from the sorbate radi
cal cations to the zeolite lattice. In the case of cycloheptatriene, t
he ratio C7H7/C7H8+. increases with the zeolite Al content. Cyclohepta
triene adsorbs to at least two types of sites; the more basic sites in
crease in number as the Al content increases, are lower in energy and
are populated first.