Unimolecular Decomposition of CL20: Strained Cage Fragmentation

Abstract Unimolecular decomposition of caged nitroamines, such as CL20, can exhibit numerous decomposition reaction ways. Apart from the conventional, well‐known mechanisms of “nitro fission” and “HONO elimination” observed for other nitroamines, the presence of strained caging leads to “strained cage fragmentation,” as demonstrated in this theoretical study. Detailed potential energy surface of the reaction pathway involving transition steps and activation energy barriers, along with validation of the products against experimental mass spectrometry results of previous experimental investigations in literature, demonstrates the alternative decomposition mechanism. This decomposition mechanism is valid for three different polymorphs of CL20. Based on changes in free energy, this decomposition mechanism (initiated under external stimuli such as shock, temperature rise, or electromagnetic excitation) is shown to be the most probable mechanism for unimolecular decomposition with final products as CO 2 , N 2 O, HCN, C 2 H 2 , HNO 3 , HCOOH and HN 3 O 4 .