An EPR Study of the Thermal Decomposition of TNT/HMB Mixtures

When trinitrotoluene (TNT) is thermally decomposed, an observable radical signal is detected after several minutes at 240 C. Addition of hexamethylbenzene (HMB) has been found to greatly reduce the temperature at which radicals may be observed (175 C or lower) and produce a radical signal which seems to be free of the polymeric species observed in the latter stages of TNT decomposition. Mixtures of TNT and HMB (.05 to .95 mole fraction of TNT) were thermally decomposed at 175 C to obtain a better identification of the radical species present in the early stages of TNT decomposition. Radical signals are observed which result from at least two species. The experimental spectra are correlated with simulated spectra of radicals derived from TNT and HMB. The relative rates of reaction and the form of the kinetic profile are dependent on the mole fraction of TNT.