Cyclic nitramine explosives

Thompson KT, FH Crocker, HE Fredrickson (2005) Mineralization of the cyclic nitramine explosive hexahydro-l,3,5-trinitro-l,3,5-triazine by Gordonia and Williamsia spp. Appl Environ Microbiol 71 8265-8272. 

In some related work, Lear and co-workers prepared the powerful cyclic nitramine explosive Keto-RDX (102) from the nitrolysis-nitration of2-oxa-5-tert-butyltriazone(101). Pagoria and co-workers " conducted a full study on the effect of different nitrating agents on the yield of Keto-RDX (Table 5.6). 

Bhushan B et al., Chemotaxis-mediated biodegradation of cyclic nitramine explosives RDX, HMX, and CL-20 by Clostridium sp. EDB2, Biochem. Biophys. Res. Commun., 316, 816, 2004. 

Rocheleau S et al., Toxicity and uptake of cyclic nitramine explosives in ryegrass Lolium perenne. Environ. Pollut., 156, 199, 2008. 

Dodard S et al., Survival and reproduction of enchytraeid worms (Oligochaeta) in different soil types amended with cyclic nitramine explosives, Environ. Toxicol. Chem., 24, 2579, 2005. 

Groom CA et al., Detection of the cyclic nitramine explosives hexahydro-l,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-l,3,5,7-tetranitro-l,3,5,7-tetrazine (HMX) and their degradation products in soil environments, J. Chromatogr. A, 909, 53, 2001. 

The cyclic nitramine explosives RDX, HMX, and CL-20 did not adversely affect plants at concentrations tested hence no plant-based ETVs could be developed for these MC. Similarly, soil invertebrate-based ETV could not be developed for HMX weathered and aged in amended soil, because the EC20 value was established only for one test species, F. Candida. HMX did not adversely affect reproduction of either earthworms or potworms in weathered and aged treatments at concentrations tested. The greatest concentrations of cyclic nitramine explosives that were tested in these studies that produced no adverse effects on the test species are shown in Table 12.5 and Table 12.6 as reference values only these values should not be considered ETVs for the respective explosives. 

A SB-P-CD-assisted EKC method for the determination of cyclic nitramine explosives and related degradation intermediates and the 14 ERA listed explosives (borate/SDS electrolyte) has been described. " A volatile electrolyte composed of SB- -CD modified ammonium acetate buffer was selected for the EKC-MS detection of nitroaromatic and cyclic nitramine compounds in soil and marine sediment, as detailed in Table 31.7. The use of phosphate/SDS electrolytes was reported in the separation of the 14 listed nitramine and nitroaromatic explosives for the analysis of extracts of high explosives such as C-4, tetrytol, and detonating cord. " ... 

C.A. Groom, A. Halasz, L. Paquet, P. D Cruz and J. Hawaii, Cuclodextrin-assisted capUlary electrophoresis for determination of the cyclic nitramine explosives RDX, HMS and CL-20. Comparison with high-performance liquid chromatography, J. Chromatogr. A, 999, 17-22, 2003. 

This nitrimine, the nominal monomer of the cyclic nitramine high explosives RDX and HMX, may be involved in their detonation and can be formed from them by pyrolysis. 

The importance of cyclic nitramines as military explosives has meant that an enormous amount of research has been conducted in this area. Only some of the rich array of products and by-products obtainable from hexamine nitrolysis are discussed in this section. For mechanistic smdies and detailed analysis of these reactions the primary research papers should be consulted. " ... 

The nitrolysis of hexamine at low temperature has led to the synthesis of a number of cyclic nitramines. The reaction of hexamine dinitrate (241) with 88 % nitric acid at -40 °C, followed by quenching the reaction mixture onto crushed ice, leads to the precipitation of 3,5-dinitro-3,5-diazapiperidinium nitrate (242) (PCX) in good yield PCX is an explosive equal in power to RDX but is slightly more sensitive to impact. The reaction of PCX (242) with sodium acetate in acetic anhydride yields l-acetyl-3,5-dinitro-l,3,5-triazacyclohexane (82) (TAX), which on further treatment with dilute alkali in ethanol yields the bicycle (243). ... 

D. Huang and R. R. Rindone, NNHT A New Low Cost Insensitive Cyclic Nitramine , Proc. Joint International Symposium on Compatibility of Plastics and Other Materials with Explosives,... 

Y. Du, M. Jiang, Q. Sun and X. Fu, Detonation Properties and Thermal Stabilities of Furazano-Fused Cyclic Nitramines , in Proc. International Symposium on Pyrotechnics and Explosives, China Academic Publishers, Beijing, China, 412 (1987). 

Nitroguanidine (NQ) is a nitramine compound containing one N-NOj group in its molecular structure. In contrast to cyclic nitramines such as HMX and RDX, its density is low and its heat of explosion is also comparatively low. However, the Mg of its combustion products is low because of the high mass fraction of hydrogen contained within the molecule. Incorporating NQ particles into a double-base propellant forms a composite propellant termed a triple-base propellant, as used in guns. 

The preceding discussion revealed that once an initial attack, whether biotic or abiotic, disturbed the cyclic nitramine (RDX, HMX, or CL-20), the subsequent degradation reactions are largely governed by the interactions of the newly formed intermediates with water to eventually produce N02, N20, NH3, HCHO, and HCOOH (Figures 2.2, 2.3, 2.5, and 2.6). Knowledge of the product distributions provides insight into the adverse effect of this family of explosives to various receptors in the environment. 

The wide use of nitro organic based energetic chemicals (NOCs), such as the aromatic TNT, and the nonaromatic cyclic nitramines RDX and HMX has resulted in the contamination of terrestrial and aquatic systems. Several reports (see Chapters 3-5 and 7-9 of this book) described the toxic and carcinogenic effects of explosives and their degradation products to various terrestrial, aquatic, and avian receptors. However, to determine the true identity of the chemicals that cause toxicity, the transport and transformation mechanisms of these chemicals must be understood. 

Zhao J-S et al., Phylogeny of cyclic nitramine-degrading psychrophilic bacteria in marine sediment and their potential role in the natural attenuation of explosives, FEMS Microbiol. Ecol., 49, 349, 2004. 

A relatively broad variety of aquatic toxicity studies exists for nitro-substituted phenol, toluene, and benzene explosives and related compounds, but very little toxicological information is available for tetryl, cyclic nitramines, and the other energetic compounds discussed in this chapter. Several explosives, such as tetryl, are no longer manufactured and are, therefore, of diminishing environmental concern, although their persistence and the nature, stability, and toxicity of their breakdown products is not understood in sufficient detail and should be further investigated. A variety of other energetic compounds, for example, perchlorates, are used in military operations, and due to environmental concerns with their release, additional studies on their fate and effects in aquatic systems are recommended. 

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