Decomposition of the polycyclic nitramine explosive, CL-20, by Fe(0)

• Published in: Environmental science & technology 2004-12, Vol.38 (24), p.6861
• Main Authors: Balakrishnan, Vimal K, Monteil-Rivera, Fanny, Halasz, Annamaria, Corbeanu, Aurelian, Hawari, Jalal
• Format: Article
• Language: English
• Subjects: Aza Compounds - chemistry; Hazardous Substances; Heterocyclic Compounds - chemistry; Iron - chemistry; Nitrogen - chemistry; Oxidation-Reduction; Soil Pollutants - analysis
• ISSN: 0013-936X
• DOI: 10.1021/es049423h

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.