THERMAL-DECOMPOSITION MECHANISM OF NTO

Thin films of NTO (5-nitro-2,4-dihydro-3H-1,2,4-triazol-3-one) are sub jected to transient pyrolysis using a pulsed infrared laser in order t o determine the initial steps of the thermal decomposition mechanism u nder rapid heating conditions, After heating, the film is quenched to 77 K in about 2 ms, thereby trapping reaction products which are subse quently detected by transmission Fourier-transform infrared spectrosco py, The first observed product of the decomposition is CO2; no evidenc e has been found for formation of NO2 or HONO in the early stages of t hermal decomposition. The experimental results show that the CO2 react ion product is formed by bimolecular oxygenation of the carbonyl group by the nitro group of an adjacent NTO molecule. This conclusion is co ntrasted with mechanisms proposed by other research groups based on sl ow heating experiments.