| Abstract | CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), C₆H₆N₁₂O₁₂, is an emerging energetic chemical that may replace RDX, but its degradation pathways are not well-known. In the present study, zerovalent iron was used to degrade CL-20 with the aim of determining its products and degradation pathways. In the absence of O₂, CL-20 underwent a rapid decomposition with the concurrent formation of nitrite to ultimately produce nitrous oxide, ammonium, formate, glyoxal, and glycolate. LC/MS (ES-) showed the presence of several key products carrying important information on the initial reactions involved in the degradation of CL-20. For instance, a doubly denitrated intermediate of CL-20 was detected together with the mono- and dinitroso derivatives of the energetic chemical. Two other intermediates with [M − H]⁻ at 392 and 376 Da, matching empirical formulas of C₆H₇N₁₁O₁₀ and C₆H₇N₁₁O₉, respectively, were detected. Using ¹⁵N-labeled CL-20, the two intermediates were tentatively identified as the denitrohydrogenated products of CL-20 and its mononitroso derivative, respectively. The present experimental findings suggest that CL-20 degraded via at least two initial routes: one involving denitration and the second involving sequential reduction of the N−NO₂ to the corresponding nitroso (N−NO) derivatives prior to denitration and ring cleavage. |
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