Combustion mechanism of tetrazole derivatives

Burning of tetrazole and 5-chlorotetrazole and temperature distribution in the combustion wave are studied. The basic peculiarity of tetrazole burning is shown to consist in that in samples with no oxidizer the combustion pro ducts contain stable high-energy nitrite derivatives rather than equilibriu m adiabatic species. As a result, only part of the energy stored in the ene rgetic material is released. Although the decomposition reactions are rare controlling steps in the combustion mechanism of these compounds, they turn out other than those controlling thermal decomposition at temperatures bet ween 150 and 250 degrees C. It is revealed that tetrazole bums in an unusua l regime in which the surface temperature undergoes cyclic variations. The process underlying this phenomenon is periodical build-up of a decompositio n product in the surface layer. The boiling/decomposition point of this pro duct is much higher than the tetrazole boiling point. The layer is periodic ally removed to clean the burning surface.