View source for Monomethylhydrazine

{{Chembox
| Watchedfields  = changed
| verifiedrevid  = 412518770
| ImageFile      = Monomethylhydrazine.png
| ImageClass     = skin-invert
| ImageFile_Ref  = {{chemboximage|correct|??}}
| ImageSize      = 100
| ImageName      = Skeletal formula of monomethylhydrazine with some implicit hydrogens shown
| ImageFile1     = Methylhydrazine-3D-balls.png
| ImageFile1_Ref = {{chemboximage|correct|??}}
| ImageSize1     = 100
| ImageName1     = Ball and stick model of monomethylhydrazine
| PIN            = Methylhydrazine<ref>{{Cite web|title=Monomethylhydrazine - Compound Summary|url=https://pubchem.ncbi.nlm.nih.gov/compound/6061|work=PubChem Compound|publisher=National Center for Biotechnology Information|access-date=2 May 2012|location=USA|date=26 March 2005|at=Identification and Related Records}}</ref>
| OtherNames     = Methyldiazane, monomethyl hydrazine
| Section1       = {{Chembox Identifiers
|CASNo = 60-34-4
|CASNo_Ref = {{cascite|correct|CAS}}
|UNII_Ref = {{fdacite|correct|FDA}}
|UNII = UWA30B5Z1J
|PubChem = 6061
|ChemSpiderID = 5837
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
|EINECS = 200-471-4
|UNNumber = 1244
|MeSHName = Monomethylhydrazine
|ChEMBL = 160520
|ChEMBL_Ref = {{ebicite|correct|EBI}}
|RTECS = MV5600000
|Beilstein = 635645
|SMILES = CNN
|StdInChI = 1S/CH6N2/c1-3-2/h3H,2H2,1H3
|StdInChI_Ref = {{stdinchicite|correct|chemspider}}
|StdInChIKey = HDZGCSFEDULWCS-UHFFFAOYSA-N
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
| Section2       = {{Chembox Properties
|Formula = {{chem2|CH6N2}}
|C=1|H=6|N=2
|Appearance = Fuming, colourless liquid
|Odor = Fish-like <ref>Methylhydrazine: odor</ref> 
|Density = 875 mg/mL (at 20&nbsp;°C)
|MeltingPtC = -52
|BoilingPtK = 360.65
|LogP = −1.318
|VaporPressure = 5.00 kPa (at 20&nbsp;°C)
|RefractIndex = 1.4325
|Solubility = Miscible<ref name=PGCH/>
}}
| Section3       = {{Chembox Thermochemistry
|DeltaHf = 54.14 kJ/mol
|DeltaHc = −1305.8 to −1304.6 kJ/mol
|Entropy = 165.94 J/(K·mol)
|HeatCapacity = 134.93 J/(K·mol)
}}
| Section4       = {{Chembox Hazards
|MainHazards= highly toxic and reactive liquid
|ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics0180.htm inchem.org]
|GHSPictograms = {{GHS flame}} {{GHS skull and crossbones}} {{GHS health hazard}} {{GHS environment}}
|GHSSignalWord = '''DANGER'''
|HPhrases = {{H-phrases|225|300|301|311|314|330|351|411}}
|PPhrases = {{P-phrases|210|260|273|280|284}}
|NFPA-H = 4
|NFPA-F = 3
|NFPA-R = 2
|NFPA-S = 
|FlashPtF = 17
|FlashPt_ref = <ref name=PGCH/>
|AutoignitionPtC = 196
|ExploLimits = 2.5–92%<ref name=PGCH/>
|LD50 = 32 mg/kg (oral, rat)
|IDLH = Ca [20 ppm]<ref name=PGCH>{{PGCH|0419}}</ref>
|LC50 = {{ubl|34 ppm (rat, 4 hr)|74 ppm (rat, 4 hr)|162 ppm (monkey, 1 hr)|195 ppm (dog, 30 min)|145 ppm (monkey, 30 min)|272 ppm (mouse, 30 min)|427 ppm (rat, 30 min)|56 ppm (mouse, 4 hr)|143 ppm (hamster, 4 hr)}}<ref>{{IDLH|60344|Methylhydrazine}}</ref>
|PEL = C 0.2 ppm (0.35 mg/m<sup>3</sup>) [skin]<ref name=PGCH/>
|REL = Ca C 0.04 ppm (0.08 mg/m<sup>3</sup>) [2-hr]<ref name=PGCH/>
}}
| Section5       = {{Chembox Related
|OtherCompounds = {{Ubl|[[Methylamine]]|[[Ethylamine]]|[[Ethylenediamine]]}}
}}
}}
'''Monomethylhydrazine''' ('''MMH''') is a highly [[toxic]], [[volatility (chemistry)|volatile]] [[hydrazine]] derivative with the [[chemical formula]] {{chem2|CH6N2}}. It is used as a [[rocket propellant]] in [[bipropellant rocket]] [[engine]]s because it is [[hypergolic propellant|hypergolic]] with various oxidizers such as [[nitrogen tetroxide]] ({{chem2|N2O4}}) and [[nitric acid]] ({{chem2|HNO3}}). As a propellant, it is described in specification MIL-PRF-27404.<ref>{{cite web |title=Propellant, Monomethylhydrazine |url=https://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=18796 |author=Air Force Petroleum Office |id=MIL-PRF-27404D |date=2012-04-20 |website=ASSIST (Database for Military Specifications and Military Standards) |via=Defense Standardization Program Automation Office |access-date=2025-02-06 |url-status=live |archive-url=https://web.archive.org/web/20250206182405/https://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=18796 |archive-date=2025-02-06 }}</ref>

'''MMH''' is a [[hydrazine]] derivative that was once used in the [[Space Shuttle Orbital Maneuvering System|orbital maneuvering system]] (OMS) and reaction control system (RCS) engines of [[NASA]]'s [[Space Shuttle]], which used MMH and [[Mixed oxides of nitrogen|MON-3]] (a mixture of nitrogen tetroxide with approximately 3% nitric oxide). This chemical is [[toxic]] and [[carcinogenic]],<ref>Monomethylhydrazine as toxic and carcinogenic chemical substance</ref> but it is easily stored in orbit, providing moderate performance for very low fuel tank system weight. MMH and its chemical relative [[unsymmetrical dimethylhydrazine]] (UDMH) have a key advantage that they are stable enough to be used in [[regenerative cooling (rocketry)|regeneratively cooled]] [[rocket engine|rocket engines]]. The [[European Space Agency]] (ESA) has attempted to seek new options in terms of [[bipropellant rocket]] combinations to avoid using deadly chemicals such as MMH and its relatives.<ref>{{cite conference |conference-url=http://esamultimedia.esa.int/conferences/01a05/index.html |conference=International Conference on Green Propellant for Space Propulsion |publisher=[[European Space Agency]] |title=Preliminary Programme |date=20–22 June 2001 |place=Noordwijk, NL}}</ref>

MMH is believed to be the primary active mycotoxin found in [[mushroom]]s of the genus ''[[Gyromitra]]'', especially the false morel (''[[Gyromitra esculenta]]''). In these cases, MMH is formed by the [[hydrolysis]] of [[gyromitrin]].<ref name=Pyysalo1975>{{cite journal |last=Pyysalo |first=H. |title=Some new toxic compounds in false morels, ''Gyromitra esculenta'' |journal=Naturwissenschaften |volume=62 |issue=8 |pages=395 |year=1975 |pmid=1238907 |doi=10.1007/BF00625355|bibcode=1975NW.....62..395P |s2cid=178876}}</ref>

Monomethylhydrazine is considered to be a possible occupational carcinogen,<ref>{{cite report |url=https://www.cdc.gov/niosh/idlh/60344.html |title=Immediately Dangerous to Life or Health Concentrations (IDLHs) |publisher=U.S. [[Centers for Disease Control and Prevention]]}}</ref> and the occupational exposure limits to MMH are set at protective levels to account for the possible carcinogenicity.<ref>{{cite report |url=https://www.cdc.gov/niosh/npg/npgd0419.html |title=NIOSH Pocket Guide to Chemical Hazards |id=NPGD&nbsp;#0419 |publisher=U.S. [[Centers for Disease Control and Prevention]]}}</ref>

A known use of MMH is in the synthesis of [[suritozole]].<ref>{{cite journal|doi=10.1021/jm00401a031 |title=2,4-Dihydro-3H-1,2,4-triazole-3-thiones as potential antidepressant agents |date=1988 |last1=Kane |first1=John M. |last2=Dudley |first2=Mark W. |last3=Sorensen |first3=Stephen M. |last4=Miller |first4=Francis P. |journal=Journal of Medicinal Chemistry |volume=31 |issue=6 |pages=1253–1258 |pmid=3373495 }}</ref>

MMH is also assumed to be the active methylating agent in the drug [[Temozolomide|temozolomide]].<ref>{{Cite web |title=Google Scholar |url=https://scholar.google.com/scholar?hl=de&as_sdt=0,5&q=temozolomide+monomethylhydrazine+&btnG=#d=gs_qabs&t=1650159695971&u=#p=V1-bTZMdygoJ |access-date=2022-04-17 |website=scholar.google.com}}</ref>

==References==
{{Reflist|25em}}

== Further reading ==
*{{Cite encyclopedia |title=Methylhydrazine |encyclopedia=Encyclopedia of Liquid Fuels |publisher=De Gruyter  |last=Schmidt |first=Eckart W.  |date=2022 |pages=3879–4202 |doi=10.1515/9783110750287-033 |isbn=978-3-11-075028-7}}
==External links==
*{{Commonscatinline}}

{{Hydrazines}}

[[Category:Rocket fuels]]
[[Category:Mycotoxins]]
[[Category:Hydrazines]]
[[Category:Monoamine oxidase inhibitors]]
[[Category:Vitamin B6 antagonists]]
[[Category:Organic compounds with 1 carbon atom]]
[[Category:Methyl compounds]]