ESR STUDY OF ADSORBED MONOMER AND DIMER CATION RADICALS OF BENZENE AND ITS METHYL DERIVATIVES.

Benzene, toluene, o-, m-, p-xylene, and mesitylene adsorbed on silica gel were γ-irradiated at −196°C. ESR spectra observed at −196°C for these systems at low contents of the methylbenzenes were assigned to the respective monomer cations. Dimer cations of benzene, toluene, and p-xylene were produced on γ-irradiation at −196°C of the adsorbed systems at higher contents and also by the reaction of monomer cations and neutral molecules at higher temperature than −160°C.