Hexanitrohexaazaisowurtzitane

Hexanitrohexaazaisowurtzitane
Names
IUPAC name
2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane
Other names
CL-20
Identifiers
Abbreviations CL-20, HNIW
135285-90-4 Yes
ChEBI CHEBI:77327 
ChemSpider 8064994 Yes
9223599 (3R,9R)-dodec Yes
9594121 (3R,5S,9R,11S)- dodec Yes
Jmol-3D images Image
Image
PubChem 9889323
11048432 (3R,9R)-dodec
11419235 (3R,5S,9R,11S)- dodec
Properties
C
6N
12H
6O
12
Molar mass 438.1850 g mol−1
Density 2.044 g cm−3
Explosive data
Detonation velocity 9.38 km s−1
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
  verify (what is: Yes/?)
Infobox references

Hexanitrohexaazaisowurtzitane /ˈhɛksɑːˈnaɪtroʊˈhɛksɑːˌæzɑːˌaɪsoʊˈvʊərtsɪteɪn/, also called HNIW and CL-20, is a nitroamine explosive with the formula C6H6N12O12, developed by the China Lake facility, primarily to be used in propellants. It has a better oxidizer-to-fuel ratio than conventional HMX or RDX. It produces 20% more energy than traditional HMX-based propellants, and is widely superior to conventional high-energy propellants and explosives.

While most development of CL-20 has been fielded by the Thiokol Corporation, the US Navy (through ONR) has also been interested in CL-20 for use in rocket propellants, such as for missiles, as it has lower observability characteristics such as less visible smoke.[1]

CL-20 has not yet been fielded in any production weapons system, but is undergoing testing for stability, production capabilities, and other weapons characteristics.

Synthesis

Synthesis of CL20

First, benzylamine (1) is condensed with glyoxal (2) under acidic and dehydrating conditions to yield the first intermediate compound, hexabenzylhexaazaisowurtzitane (3). Four benzyl groups selectively undergo hydrogenolysis using palladium on carbon and hydrogen. The amino groups are then acetylated during the same step using acetic anhydride as the solvent, yielding dibenzyltetraethanoylhexaazaisowurtzitane (4). Finally, compound 4 is reacted with nitronium tetrafluoroborate and nitrosonium tetrafluoroborate, resulting in HNIW.

Cocrystal product with HMX

In August 2012, Onas Bolton et al published results showing that a cocrystal of 2 parts CL-20 and 1 part HMX had similar safety properties to HMX, but with a greater firing power closer to CL-20. [2][3]

Cocrystal product with TNT

In August 2011, Adam Matzger and Onas Bolton published results showing that a cocrystal of CL-20 and TNT had twice the stability of CL-20—safe enough to transport, e.g. -- but by heating to 136 C can be separated into TNT and a form of CL-20 with structural defects that is somewhat less stable than CL-20.[4]

See also

References

  1. ↑ Yirka, Bob (9 September 2011). "University chemists devise means to stabilize explosive CL-20". Physorg.com. Retrieved 8 July 2012.
  2. ↑ High Power Explosive with Good Sensitivity: A 2:1 Cocrystal of CL-20:HMX, Crystal Growth & Design (American Chemical Society), 2012, 12 (9), pp 4311–4314, DOI: 10.1021/cg3010882, Publication Date (Web): August 7, 2012, accessed 7 September 2012
  3. ↑ Powerful new explosive could replace today's state-of-the-art military explosive, SpaceWar.com, 6 September 2012, accessed 7 September 2012
  4. ↑ Angewandte Chemie International Edition]

Further reading