Thermal Decomposition of Energetic Materials 33: The Thermolysis Pathway of the Azidodinitromethyl Group

Abstract

Rapid-scan FT-IR studies are reported for the thermal decomposition of R (CH₂)₃C(NO₂)₂N₃ (R = CH₃OC(O)-, HO-, -OC(O)O-, and O₂NO-) at a heating rate of 70°C/s or higher. The thermolysis is initiated by the -C(NO₂)₂N, group. At 15 psi Ar, a sharp exotherm occurs at about 180°C. Except when R = O₂NO-, the gas products are NO₂, N₂ (inferred), and R(CH₂)₃CN, making the rapid thermal decomposition one of the most straightforward yet observed for an energetic functional group. At an Ar gas pressure of 500 psi, the products are altered only to the extent that partial oxidation of the organonitrile occurs. The exotherm remains at about 180°C but is greatly accentuated. When R = O₂NO-, the thermolysis temperature profile is very similar to the other compounds, but an organonitrile is not detected. Instead, at 15 psi Ar, a mixture of gas products resulting from the reaction of NO, with the backbone is detected, indicating that the nitrate ester also reacts. At 500 psi Ar, the products and thermal profile of this compound are characteristic of an explosion.