Kinetics and chemistry of thermal decomposition of FOX 7

Formal kinetics of the two step decomposition of FOX 7 (1,1-diamino-2,2-dinitroethylene) was modelled using dynamic and isothermal DTA/TGA measurements. As a consequence of the extremely high values of the activation energy, FOX 7 is a very stable high explosive even at elevated temperatures. The reaction product (RP) remaining after the first decomposition step (corresponding to about 38 % mass loss) was investigated by NMR, X-ray diffraction, IR and HPLC. Surprisingly all methods seem to confirm the identity of the solid RP with the initial compound FOX 7. Consequently the compound decomposing in the first step is assumed to be a less stable amorphous fraction of FOX 7.