CL-20 analogues: Structure - Thermal stability/decomposition mechanism relationships

The thermal decomposition of a number of analogues of hexanitrohexaazaisowurtzitan (CL-20), in where one or more N-nitro groups have been replaced by another explosophoric unit (diverse N-alkylnitramine groups or N- trinitroethyl), has been studied by methods of isothermal and non-isothermal kinetics. It was found that replacing the N-nitro group with even a more thermally stable substituent leads to a decrease in the stability of the nitrated hexaazaisowurtzitane framework. It was suggested that the substituent distorts the symmetry of the strained hexaazaisowurtzitane cage, which affects the strength of the N–NO₂ bond. When a substituent less stable than the N-nitro group in the parent CL-20 is installed, the initial stage of degradation is determined by the decomposition kinetics of this substituent. One of the objects of this study, 4,10-dinitro-2,6,8,12-tetrakis (2,2,2-trinitroethyl) −2,4,6,8,10,12-hexaazaisowurtzitane (8), was synthesized for the first time; it was fully characterized and also confirmed by X-ray structural data.