FOX-7

FOX-7 or 1,1-diamino-2,2-dinitroethylene (DADNE)[3] is an insensitive high explosive compound. It was first synthesized in 1998 by the Swedish National Defence Research Institute (FOS).[4] The name FOX-7 is derived from the acronym of the Swedish Defence Research Agency (FOI), with the I replaced by an X to indicate an explosive, as in RDX and HMX.[5]

FOX-7

Names
IUPAC name 2,2-dinitroethene-1,1-diamine
Other names FOX-7 FOX7
Identifiers
CAS Number	145250-81-3
3D model (JSmol)	Interactive image
ChemSpider	467536
ECHA InfoCard	100.130.630
EC Number	604-466-1
PubChem CID	536770
UNII	3B2KYV7C3F
CompTox Dashboard (EPA)	DTXSID70894014
InChI InChI=1S/C2H4N4O4/c3-1(4)2(5(7)8)6(9)10/h3-4H2 Key: FUHQFAMVYDIUKL-UHFFFAOYSA-N
SMILES N/C(N)=C([N+]([O-])=O)\[N+]([O-])=O
Properties
Chemical formula	C2H4N4O4
Molar mass	148.08
Appearance	Bright yellow crystalline powder[1]
Density	1.885 g cm^−3
Melting point	238 °C (460 °F; 511 K) (decomposes)
Solubility in water	Soluble in dipolar aprotic solvents such as dimethyl sulfoxide (DMSO), N,N-Dimethylformamide (DMF), and N-Methyl-2-pyrrolidone (NMP)[1]
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H201, H228, H302
GHS precautionary statements	P210, P230, P240, P241, P250, P264, P270, P280, P301+312, P330, P370+378, P370+380, P372, P373, P401, P501
Explosive data
Friction sensitivity	>350N[2]
Detonation velocity	8870 m/s at density 1.885 g cm^−3 (estimated) 8335 m/s at density 1.756 g cm^−3 (measured, small-scale testing)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
verify (what is  ?)
Infobox references

FOX-7 is similar to the insensitive chemical compound TATB, which is a benzene ring compound with three amino and three nitro groups.[6] FOX-7 has a two-carbon backbone rather than a benzene ring, but the amino and nitro groups have similar effects in both cases according to published reports on the sensitivity and chemical decay processes of FOX-7.[1] FOX-7 is stoichiometrically identical (but structurally unrelated)[2] to the explosives and propellants RDX and HMX, and therefore produces the same quantity of gas per gram, a key determinant of performance.[1]

By various measures, such as dropped-weight impact, friction force, temperature of ignition, and response to heating under confinement, it is less sensitive than the benchmark explosive RDX, while having performance slightly greater than the same.[2] Its explosive properties appear extremely favorable; in addition to its insensitive properties, the detonation velocity of mixtures of 80% FOX-7 plus binders is as high as Composition B, and nearly pure FOX-7 based plastic bonded explosives are slightly superior to RDX.[7] FOX-7 has been calculated to have a detonation velocity of 8,870 m/s.[8] Charges composed of EVA-coated FOX-7 granules pressed into pellets of 92% theoretical maximum density were found to have a detonation velocity of 7730 m/s, compared to 7630 m/s for a similar RDX/EVA composition, and 5% greater detonation pressure.[2]

FOX-7 is produced as of 2018 by EURENCO Bofors AB of Sweden,[9] having been made in batches up to 7kg in 2001.[10] In laboratory scale synthesis, material costs were calculated at ~AU$3000/kg (prices in 2002 AUD) using prices from research chemical suppliers. At that time, FOX-7 could be purchased from NEXPLO Bofors AB at SEK3200/kg.[2] Due to its small-scale production, the cost of FOX-7 is relatively high. However, the production is based on commercial starting material and the synthesis is uncomplicated.[11]

FOX-7 is an attractive subject for research and development due to its combination of insensitivity and power. FOX-7 performs similarly to RDX, one of the most powerful explosives and propellants in use, unlike other insensitive high explosives under investigation, such as TATB, nitrotriazolone, TEX, and 2,6-Diamino-3,5-Dinitropyrazine-1-Oxide (LLM-105). Due to the need for less sensitive munitions, FOX-7 is being investigated at many military research centers,[1] including in Australia, India, the USA, and Sweden.

References

1. Anniyappan, M.; Talawar, M.B.; Gore, G.M.; Venugopalan, S.; Gandhe, B.R. (2006). "Synthesis, characterization and thermolysis of 1,1-diamino-2,2-dinitroethylene (FOX-7) and its salts". Journal of Hazardous Materials. 137 (2): 812–9. doi:10.1016/j.jhazmat.2006.03.034. PMID 16701943.
2. Ian J., Lochert (November 2001). FOX-7 - A New Insensitive Explosive (PDF) (Technical report). Fisherman's Bend, Victoria, Australia: Defense Science & Technology Organization. DSTO-TR-1238. Archived (PDF) from the original on 2021-01-25. Retrieved 2021-01-25.CS1 maint: date and year (link)
3. US Patent 6340780 - Method of preparing salts of dinitromethane
4. Bemm, U.; Östmark, H. (1998) "1,1-Diamino-2,2-dinitroethylene: a Novel Energetic Material with Infinite Layers in Two Dimensions". Acta Cryst C54: 1997-1999. doi:10.1107/S0108270198007987.
5. Viswanath, Dabir S.; Ghosh, Tushar K.; Boddu, Veera M. (2018), "FOX-7 (1,1-Diamino-2,2-Dinitroethylene)", Emerging Energetic Materials: Synthesis, Physicochemical, and Detonation Properties, Dordrecht: Springer Netherlands, pp. 101–139, doi:10.1007/978-94-024-1201-7_3, ISBN 978-94-024-1199-7, retrieved 2021-01-25
6. Hervé, Grégoire; Jacob, Guy; Latypov, Nikolaj (2005). "The reactivity of 1,1-diamino-2,2-dinitroethene (FOX-7)". Tetrahedron. 61 (28): 6743. doi:10.1016/j.tet.2005.05.010.
7. Latypov, Nikolai V.; Bergman, Jan; Langlet, Abraham; Wellmar, Ulf; Bemm, Ulf (1998). "Synthesis and reactions of 1,1-diamino-2,2-dinitroethylene". Tetrahedron. 54 (38): 11525–11536. doi:10.1016/s0040-4020(98)00673-5.
8. Detonation and Sensitivity Properties of FOX-7 and Formulations Containing FOX-7 Archived 2005-05-22 at the Wayback Machine, Karlsson et al., 2002, accessed Aug 25, 2005
9. Sleadd, Bradley A.; Boruta, David T.; Clubb, Joseph W. (24 April 2018). Development of a CONUS manufacturing capability for FOX-7 (PDF) (Technical report). National Defense Industrial Association. Archived (PDF) from the original on 25 January 2021. Retrieved 25 January 2021.CS1 maint: date and year (link)
10. Ostmark, Henric; Bergman, Helena; Bemm, Ulf; Goede, Patrick (6 July 2001). "Energetic Materials: Ignition, Combustion and Detonation". 2, 2-dinitro-ethene-1, 1-diamine(FOX-7)- Properties, analysis and scale-up. 32nd International Conference of ICT. Karlsruhe, Germany: Fraunhofer-Institut für Chemische Technologie. pp. 26-1–26-21. Archived from the original on 2021-01-25. Retrieved 2021-01-25.
11. US Patent 6312538 - Chemical compound suitable for use as an explosive, intermediate and method for preparing the compound

Further reading

• Sorescu, Dan C.; Boatz, Jerry A.; Thompson, Donald L. (2001). "Classical and Quantum-Mechanical Studies of Crystalline FOX-7 (1,1-Diamino-2,2-dinitroethylene)". The Journal of Physical Chemistry A. 105 (20): 5010. Bibcode:2001JPCA..105.5010S. doi:10.1021/jp010289m.
• Evers, Jürgen; Klapötke, Thomas M.; Mayer, Peter; Oehlinger, Gilbert; Welch, Jan (2006). "Α- and β-FOX-7, Polymorphs of a High Energy Density Material, Studied by X-ray Single Crystal and Powder Investigations in the Temperature Range from 200 to 423 K". Inorganic Chemistry. 45 (13): 4996–5007. doi:10.1021/ic052150m. PMID 16780321.