EPR investigation of thermal decay of radiation-induced species of benzoic acid and its sodium and potassium salts.

The structural and kinetic features of the radiation-induced radicals of benzoic acid and its sodium and potassium salts were investigated using electron paramagnetic resonance (EPR) spectroscopy. Two main different radicals were found to be responsible for the measured spectra of the irradiated samples. It is concluded that these two radicals have a structure similar to that of cyclohexadienyl-type (CHD) and benzyl-type (BNZ) radicals. The relative contributions of the CHD and BNZ radicals to the measured peak-to-peak amplitude and to the total spectra were calculated. The room-temperature stability of the EPR signals and the decay kinetic features of the radiation-induced radicals derived from annealing at high temperatures were determined.