View source for HMX

{{other uses}}
{{chembox
| Watchedfields = changed
| verifiedrevid = 443852936
| Name = 
| ImageFile = HMX.png
| ImageSize = 
| ImageFile2 = HMX-3D-balls.png
| PIN = 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane
| SystematicName = 
| OtherNames = Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine
| IUPACName = 
| Section1 = {{Chembox Identifiers
 | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
 | ChemSpiderID = 16636
 | InChI = 1/C4H8N8O8/c13-9(14)5-1-6(10(15)16)3-8(12(19)20)4-7(2-5)11(17)18/h1-4H2
 | InChIKey = UZGLIIJVICEWHF-UHFFFAOYAL
 | StdInChI_Ref = {{stdinchicite|correct|chemspider}}
 | StdInChI = 1S/C4H8N8O8/c13-9(14)5-1-6(10(15)16)3-8(12(19)20)4-7(2-5)11(17)18/h1-4H2
 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
 | StdInChIKey = UZGLIIJVICEWHF-UHFFFAOYSA-N
 | CASNo_Ref = {{cascite|correct|CAS}}
 | CASNo =	2691-41-0
 | UNII_Ref = {{fdacite|correct|FDA}}
 | UNII = LLW94W5BSJ
 | PubChem =17596
 | ChEBI_Ref = {{ebicite|correct|EBI}}
 | ChEBI = 33176
 | SMILES =C1N(CN(CN(CN1[N+](=O)[O-])[N+](=O)[O-])[N+](=O)[O-])[N+](=O)[O-]
 }}
| Section2 = {{Chembox Properties
 | Formula =C<sub>4</sub>H<sub>8</sub>N<sub>8</sub>O<sub>8</sub>
 | MolarMass =296.155 g/mol
 | Appearance =
 | Density =1.91 g/cm<sup>3</sup>, solid
 | MeltingPtC = 276 to 286
 | MeltingPt_notes = 
 | BoilingPt =
 | Solubility =
 }}
| Section3 = {{Chembox Explosive
 | ShockSens = Low
 | FrictionSens = Low
 | DetonationV = 9100 m/s
 | REFactor = 1.70 }}
 | Section4 = {{Chembox Hazards
 | GHSPictograms = {{GHS01}} {{GHS06}}
 | GHSSignalWord = '''DANGER'''
 | HPhrases = {{H-phrases|201|205|241|301|304|319|311}}
 | PPhrases = {{P-phrases|210|250|280|370+380|372|373}}
 | NFPA-F = 1
 | NFPA-H = 3
 | NFPA-R = 3
 | MainHazards = Explosive
 | FlashPt = 
 | AutoignitionPt = 
 }}
| Section5 = 
| Section6 = 
}}

'''HMX''', also called '''octogen''', is a powerful and relatively insensitive [[nitroamine]] [[high explosive]] chemically related to [[RDX]]. The compound's name is the subject of much speculation, having been variously listed as '''High Melting Explosive''', '''High-velocity Military Explosive''', or '''High-Molecular-weight RDX'''.<ref>Cooper, Paul W., ''Explosives Engineering'', New York: Wiley-VCH, 1996.  {{ISBN|0-471-18636-8}}</ref>

The molecular structure of HMX consists of an eight-membered ring of alternating carbon and nitrogen atoms, with a nitro group attached to each nitrogen atom. Because of its high mass-specific [[enthalpy of formation]], it is one of the most potent chemical explosives manufactured, although a number of newer ones, including [[Hexanitrohexaazaisowurtzitane|HNIW]], [[TKX-50]], and [[octanitrocubane|ONC]], are more powerful.<ref name="Klapötke1">{{citation|author=Niko Fischer, Dennis Fischer, Thomas M. Klapötke, Davin G. Piercey, Jörg Stierstorfer |date=2012 |doi=10.1039/C2JM33646D |issue=38 |pages=20418–20422 |periodical=Journal of Materials Chemistry |title=Pushing the limits of energetic materials – the synthesis and characterization of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate |volume=22}}<!-- auto-translated from German by Module:CS1 translator --></ref>

==Synthesis==
HMX is more complicated to manufacture than most explosives, and this confines it to specialist applications. It and [[RDX]] are both produced by the [[RDX#Bachmann process|Bachmann process]]—nitration of [[hexamine]] using a mixture of [[ammonium nitrate]] and [[nitric acid]] in a mixture of [[acetic acid]] and [[acetic anhydride]] as solvent—with the major product determined by the specific reaction conditions.<ref name="globalsecurity1">{{cite web|author=John Pike |url=http://www.globalsecurity.org/military/systems/munitions/explosives-nitramines.htm |title=Nitramine Explosives |publisher=Globalsecurity.org |date=1996-06-19 |access-date=2012-05-24}}</ref>

==Applications==
Also known as cyclotetramethylene-tetranitramine, tetrahexamine tetranitramine, or {{chem name|octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine}}, HMX was first made in 1930. In 1949 it was discovered that HMX can be prepared by [[nitrolysis]] of RDX. Nitrolysis of RDX is performed by dissolving RDX in a 55% [[Nitric acid|HNO<sub>3</sub>]] solution, followed by placing the solution on a steambath for about six hours.<ref>WE Bachmann, JC Sheehan (1949). "A New Method of Preparing the High Explosive RDX1". ''Journal of the American Chemical Society'', 1949 (5):1842–1845.</ref> HMX is used almost exclusively in military applications, including as the detonator in [[atomic weapon|nuclear weapons]], in the form of [[polymer-bonded explosive]], and as a solid-[[rocket]] [[solid propellant|propellant]].

HMX is used in melt-castable explosives when mixed with [[trinitrotoluene|TNT]], which as a class are referred to as "[[octol]]s". Additionally, [[polymer-bonded explosive]] compositions containing HMX are used in the manufacture of missile [[warhead]]s and armor-piercing [[shaped charge]]s.

HMX is also used in the process of [[Perforation (oil well)|perforating the steel casing in oil and gas wells]].  The HMX is built into a shaped charge that is detonated within the wellbore to punch a hole through the steel casing and surrounding cement out into the hydrocarbon-bearing formations.  The pathway that is created allows formation fluids to flow into the wellbore and onward to the surface.<ref>{{Citation|title=Casing Perforation Overview|first = Brad|last = Hansen|contribution = Technical Presentation Session 3: Drilling and Completion Casing Perforating Overview|contribution-url=https://www.epa.gov/sites/default/files/documents/casingperforatedoverview.pdf|series = EPA's Study of Hydraulic Fracturing and Its Potential Impact on Drinking Water Resources| date=11 March 2013 |publisher = U.S. Environmental Protection Agency | url = https://www.epa.gov/hfstudy/casing-perforating-overview| archive-url = https://web.archive.org/web/20131020080109/http://www2.epa.gov/hfstudy/casing-perforating-overview| archive-date = October 20, 2013}}</ref><ref>{{cite journal |last1=Liu |first1=He |last2=Wang |first2=Feng |last3=Weng |first3=Yucai |last4=Gao |first4=Yang |last5=Cheng |first5=Jianlong |date=December 2014 |title= Oil well perforation technology: Status and prospects|journal= Petroleum Exploration and Development|volume= 41|issue= 6|pages=798–804 |doi=10.1016/S1876-3804(14)60096-3 |bibcode=2014PEDO...41..798L |doi-access=free }}</ref>

The ''[[Hayabusa2]]'' space probe used HMX to excavate a hole in an [[asteroid]] in order to access material that had not been exposed to the [[solar wind]].<ref>{{cite journal | doi =10.1016/j.actaastro.2012.11.010|bibcode = 2013AcAau..84..227S | title =Small carry-on impactor of Hayabusa2 mission | year =2013 | last1 =Saiki | first1 =Takanao | last2 =Sawada | first2 =Hirotaka | last3 =Okamoto | first3 =Chisato | last4 =Yano | first4 =Hajime | last5 =Takagi | first5 =Yasuhiko | last6 =Akahoshi | first6 =Yasuhiro | last7 =Yoshikawa | first7 =Makoto | journal =Acta Astronautica | volume =84 | pages =227–236 }}</ref>

Ongoing research aims to reduce its sensitivity and improve some manufacturing properties.<ref>{{Cite journal|last1=Kosareva|first1=Ekaterina K.|last2=Zharkov|first2=Mikhail N.|last3=Meerov|first3=Dmitry B.|last4=Gainutdinov|first4=Radmir V.|last5=Fomenkov|first5=Igor V.|last6=Zlotin|first6=Sergei G.|last7=Pivkina|first7=Alla N.|last8=Kuchurov|first8=Ilya V.|last9=Muravyev|first9=Nikita V.|date=January 2022|title=HMX surface modification with polymers via sc-CO2 antisolvent process: A way to safe and easy-to-handle energetic materials|url=https://linkinghub.elsevier.com/retrieve/pii/S1385894721029442|journal=Chemical Engineering Journal|language=en|volume=428|article-number=131363|doi=10.1016/j.cej.2021.131363|url-access=subscription}}</ref><ref>{{Cite journal|last1=Lin|first1=Congmei|last2=Zeng|first2=Chengcheng|last3=Wen|first3=Yushi|last4=Gong|first4=Feiyan|last5=He|first5=Guansong|last6=Li|first6=Yubin|last7=Yang|first7=Zhijian|last8=Ding|first8=Ling|last9=Li|first9=Jiang|last10=Guo|first10=Shaoyun|date=2020-01-22|title=Litchi-like Core–Shell HMX@HPW@PDA Microparticles for Polymer-Bonded Energetic Composites with Low Sensitivity and High Mechanical Properties|url=https://pubs.acs.org/doi/10.1021/acsami.9b20323|journal=ACS Applied Materials & Interfaces|language=en|volume=12|issue=3|pages=4002–4013|doi=10.1021/acsami.9b20323|pmid=31874021 |s2cid=209473864 |issn=1944-8244|url-access=subscription}}</ref>

== Health and environmental fate ==

=== Analytical methods ===
HMX enters the environment through air, water, and soil because it is widely used in military and civil applications. At present, reverse-phase HPLC and more sensitive LC-MS methods have been developed to accurately quantify the concentration of HMX in a variety of matrices in environmental assessments.<ref>{{Cite journal|last1=Liu|first1=Jun|last2=Severt|first2=Scott A.|last3=Pan|first3=Xiaoping|last4=Smith|first4=Philip N.|last5=McMurry|first5=Scott T.|last6=Cobb|first6=George P.|date=2007-02-15|title=Development of an extraction and cleanup procedure for a liquid chromatographic–mass spectrometric method to analyze octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine in eggs|journal=Talanta|volume=71|issue=2|pages=627–631|doi=10.1016/j.talanta.2006.05.007|pmid=19071351}}</ref><ref>{{Cite journal|last1=Pan|first1=Xiaoping|last2=Zhang|first2=Baohong|last3=Tian|first3=Kang|last4=Jones|first4=Lindsey E.|last5=Liu|first5=Jun|last6=Anderson|first6=Todd A.|last7=Wang|first7=Jia-Sheng|last8=Cobb|first8=George P.|date=2006-07-30|title=Liquid chromatography/electrospray ionization tandem mass spectrometry analysis of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)|journal=Rapid Communications in Mass Spectrometry|language=en|volume=20|issue=14|pages=2222–2226|doi=10.1002/rcm.2576|pmid=1679187|bibcode=2006RCMS...20.2222P |issn=1097-0231}}</ref>

=== Toxicity ===
At present, the information needed to determine if HMX causes cancer is insufficient. Due to the lack of information, EPA has determined that HMX is not classifiable as to its human carcinogenicity.<ref>"Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetr... (HMX) (CASRN 2691-41-0) | IRIS | US EPA." EPA. Environmental Protection Agency, n.d. Web. 15 Nov. 2012.[https://archive.today/20120729231844/http://www.epa.gov/iris/subst/0311.htm]</ref>

The available data on the effects on human health of exposure to HMX are limited. HMX causes CNS effects similar to those of RDX, but at considerably higher doses. In one study, volunteers submitted to [[patch test]]ing, which produced skin irritation. Another study of a cohort of 93 workers at an ammunition plant found no hematological, hepatic, autoimmune, or renal diseases. However, the study did not quantify the levels of exposure to HMX.

HMX exposure has been investigated in several studies on animals. Overall, the toxicity appears to be quite low. HMX is poorly absorbed by ingestion. When applied to the dermis, it induces mild skin irritation but not delayed contact sensitization. Various acute and subchronic neurobehavioral effects have been reported in rabbits and rodents, including ataxia, sedation, hyperkinesia, and convulsions. The chronic effects of HMX that have been documented through animal studies include decreased hemoglobin, increased serum alkaline phosphatase, and decreased albumin. Pathological changes were also observed in the animals' livers and kidneys.

Gas exchange rate was used as an indicator of chemical stress in Northern bobwhite quail (''Colinus virginianus'') eggs, and no evidence of alterations in metabolic rates associated with HMX exposure was observed.<ref>{{Cite journal|last1=Liu|first1=Jun|last2=Cox|first2=Stephen B.|last3=Beall|first3=Blake|last4=Brunjes|first4=Kristina J.|last5=Pan|first5=Xiaoping|last6=Kendall|first6=Ronald J.|last7=Anderson|first7=Todd A.|last8=McMurry|first8=Scott T.|last9=Cobb|first9=George P.|date=2008-05-01|title=Effects of HMX exposure upon metabolic rate of northern bobwhite quail (Colinus virginianus) in ovo|journal=Chemosphere|volume=71|issue=10|pages=1945–1949|doi=10.1016/j.chemosphere.2007.12.024|issn=0045-6535|pmid=18279915|bibcode=2008Chmsp..71.1945L}}</ref> No data are available concerning the possible reproductive, developmental, or carcinogenic effects of HMX.<ref name="globalsecurity1" /><ref>{{cite web |url=http://mmr-iagwsp.org/community/facts/hmx.html |title=Fact Sheets |publisher=Mmr-iagwsp.org |access-date=2012-05-24 |archive-date=2014-02-22 |archive-url=https://web.archive.org/web/20140222040517/http://mmr-iagwsp.org/community/facts/hmx.html }}</ref> HMX is considered less toxic than [[trinitrotoluene|TNT]] or [[RDX]].<ref>{{cite web|url=http://www.osti.gov/bridge/servlets/purl/42530-YqJ6RG/webviewable/42530.pdf |title=Information Bridge: DOE Scientific and Technical Information - Sponsored by OSTI |publisher=Osti.gov |date= December 1994|access-date=2012-05-24|last1=Daniels |first1=J. I. |last2=Knezovich |first2=J. P. }}</ref> Remediating HMX-contaminated water supplies has proven to be successful.<ref>Newell, Charles. "Treatment of RDX & HMX Plumes Using Mulch Biowalls."  ESTCP Project ER-0426. 2008.</ref>

=== Biodegradation ===
Both wild and transgenic plants can [[phytoremediation|phytoremediate]] explosives from soil and water.<ref>{{cite journal|date=December 2012|title=Phytoremediation of explosives (TNT, RDX, HMX) by wild-type and transgenic plants|journal=Journal of Environmental Management|volume=113|pages=85–92|doi=10.1016/j.jenvman.2012.08.016|pmid=22996005|author1=Panz K|author2=Miksch K|bibcode=2012JEnvM.113...85P }}</ref>

==See also==
*[[2,4,6-Tris(trinitromethyl)-1,3,5-triazine]]
*[[4,4'-Dinitro-3,3'-diazenofuroxan]] (DDF)
*[[Heptanitrocubane]] (HNC)
*[[HHTDD]]
*[[Octanitrocubane]] (ONC)
*[[RE factor]]

==Notes==
{{Reflist}}

==References==
* {{cite book |last=Cooper |first=Paul W. |year=1996 |title=Explosives Engineering |url=https://books.google.com/books?id=5MlTAAAAMAAJ |location=New York |publisher=Wiley-VCH |isbn=978-0-471-18636-6 |oclc=34409473 |access-date=9 June 2014 }}
* {{cite book |last=Urbanski |first=Tadeusz |year=1967 |title=Chemistry and Technology of Explosives |others=Vol. III |location=Warszawa |publisher=Polish Scientific Publishers }}

== Further reading ==
*{{Cite encyclopedia |title=Nitramines |encyclopedia=Encyclopedia of Liquid Fuels |publisher=De Gruyter  |last=Schmidt |first=Eckart W. |date=2022 |pages=4327–4371 |doi=10.1515/9783110750287-035 |isbn=978-3-11-075028-7|chapter=1,3,5,7-Tetranitro-1,3,5,7-tetraazacyclooctane, Octogen (HMX)}}

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{{DEFAULTSORT:Hmx}}
[[Category:Explosive chemicals]]
[[Category:Nitroamines]]
[[Category:Nitrogen heterocycles]]
[[Category:Eight-membered rings]]