Hydrazine: Difference between revisions

{{Short description|Colorless flammable liquid with an ammonia-like odor}}

{{cs1 config|name-list-style=vanc}}

{{For|the class of antidepressants|hydrazine (antidepressant)}}

{{Distinguish|hydralazine|hydroxyzine}}

{{Use American English|date=July 2019}}<!-- This article uses American spelling.-->

|Verifiedfields = changed

|Watchedfields = changed

|verifiedrevid = 458641690

|ImageFileL1 = Hydrazin.svg

|ImageFileL1_Ref = {{chemboximage|correct|??}}

|ImageNameL1 = Skeletal formula of hydrazine with all explicit hydrogens added

|ImageFileR1 = Hydrazine-3D-vdW.png

|ImageFileR1_Ref = {{chemboximage|correct|??}}

|ImageNameR1 = Spacefill model of hydrazine

|ImageFileL2 = Hydrazine-2D-A1.png

|ImageFileL2_Ref = {{chemboximage|correct|??}}

|ImageNameL2 = Stereo, skeletal formula of hydrazine with all explicit hydrogens added

|ImageFileR2 = Hydrazine-3D-balls.png

|ImageFileR2_Ref = {{chemboximage|correct|??}}

|ImageNameR2 = Ball and stick model of hydrazine

|ImageFile3 = Anhydrous hydrazine.png

|ImageCaption3 = Anhydrous hydrazine

| ImageSize3 = 180px

|IUPACName = Hydrazine<ref name = "hydrazine - PubChem Public Chemical Database" >{{Cite web|url=https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=9321|title=hydrazine—PubChem Public Chemical Database|work=The PubChem Project|location=USA|publisher=National Center for Biotechnology Information}}</ref>

|SystematicName = Diazane<ref name = "hydrazine - PubChem Public Chemical Database" />

|OtherNames = Diamine<ref name=NIOSH>{{Cite web|title=NIOSH Guide—Hydrazine|url=https://www.cdc.gov/niosh/npg/npgd0329.html|publisher=Centers for Disease Control|access-date=16 Aug 2012}}</ref><br />Tetrahydridodinitrogen(''N''-''N'')<br />Diamidogen

|Section1={{Chembox Identifiers

|CASNo = 302-01-2

|CASNo_Ref = {{cascite|correct|CAS}}

|PubChem = 9321

|ChemSpiderID = 8960

|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

|UNII = 27RFH0GB4R

|UNII_Ref = {{fdacite|correct|FDA}}

|EINECS = 206-114-9

|UNNumber = 2029

|KEGG = C05361

|KEGG_Ref = {{keggcite|correct|kegg}}

|MeSHName = Hydrazine

|ChEBI_Ref = {{ebicite|correct|EBI}}

|ChEBI = 15571

|ChEMBL = 1237174

|ChEMBL_Ref = {{ebicite|changed|EBI}}

|RTECS = MU7175000

|Beilstein = 878137

|Gmelin = 190

|3DMet = B00770

|SMILES = NN

|StdInChI = 1S/H4N2/c1-2/h1-2H2

|StdInChI_Ref = {{stdinchicite|correct|chemspider}}

|InChI = 1/H4N2/c1-2/h1-2H2

|StdInChIKey = OAKJQQAXSVQMHS-UHFFFAOYSA-N

|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

|InChIKey = OAKJQQAXSVQMHS-UHFFFAOYAZ

}}

|Section2={{Chembox Properties

|Formula = {{Chem2|N2H4}}

|MolarMass = 32.0452 g/mol

|Appearance = Colorless, fuming, oily liquid<ref name=PGCH/>

|Odor = [[Ammonia]]-like<ref name=PGCH/>

|Density = 1.021 g/cm³

|MeltingPtK = 275

|BoilingPtK = 387

|LogP = 0.67

|VaporPressure = 1 kPa (at 30.7 °C)

|pKa = 8.10 ({{chem2|[N2H5]+}})<ref>{{Cite journal |display-authors=et al|vauthors=Hall HK|year=1957|title=Correlation of the Base Strengths of Amines1|journal=[[Journal of the American Chemical Society|J. Am. Chem. Soc.]]|volume=79|issue=20|page=5441|doi=10.1021/ja01577a030}}</ref>

|ConjugateAcid = [[Hydrazinium]]

|pKb = 5.90

|RefractIndex = 1.46044 (at 22 °C)

|Viscosity = 0.876 cP

|Solubility = Miscible<ref name=PGCH/>

|Section3={{Chembox Structure

|MolShape = Triangular pyramidal at N

|Dipole = 1.85 D<ref name="Greenwood 1997">{{Greenwood&Earnshaw2nd}}</ref>

|Section4={{Chembox Thermochemistry

|DeltaHf = 50.63 kJ/mol

|Entropy = 121.52 J/(K·mol)

|Section5={{Chembox Hazards

|ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics0281.htm ICSC 0281]

|GHSPictograms = {{GHS flame}} {{GHS corrosion}} {{GHS skull and crossbones}} {{GHS health hazard}} {{GHS environment}}

|GHSSignalWord = '''DANGER'''

|HPhrases = {{H-phrases|226|301|311|314|317|331|350|410}}

|PPhrases = {{P-phrases|201|261|273|280|301+310|305+351+338}}

|NFPA-F = 4

|NFPA-H = 4

|NFPA-R = 3

|FlashPtC = 52

|AutoignitionPtC = 24 to 270

|ExploLimits = 1.8–100%

|LD50 = 59–60 mg/kg (oral in rats, mice)<ref>{{Cite book |display-authors=et al|vauthors=Martel B, Cassidy K|title=Chemical Risk Analysis: A Practical Handbook|publisher=Butterworth–Heinemann |location=Amsterdam|year=2004|page=361|isbn=978-1-903996-65-2|oclc=939257974}}</ref>

|PEL = TWA 1 ppm (1.3 mg/m³) [skin]<ref name=PGCH>{{PGCH|0329}}</ref>

|IDLH = Ca [50 ppm]<ref name=PGCH/>

|REL = Ca C 0.03 ppm (0.04 mg/m³) [2-hour]<ref name=PGCH/>

|LC50 = 260 ppm (rat, 4 [[hour|h]])<br/>630 ppm (rat, 1 h)<br/>570 ppm (rat, 4 h)<br/>252 ppm (mouse, 4&nbsp;h)<ref name=IDLH>{{IDLH|302012|Hydrazine}}</ref>

|Section6={{Chembox Related

|OtherCations = [[Hydrazines|Organic hydrazines]]

|OtherAnions = [[Tetrafluorohydrazine]]<br/>[[Hydrogen peroxide]]<br/>[[Diphosphane]]<br/>[[Diphosphorus tetraiodide]]

|OtherFunction_label = Binary [[azane]]s

|OtherFunction = [[Ammonia]]<br/>[[Triazane]]

|OtherCompounds = [[Diazene]]<br/>[[Triazene]]<br/>[[Tetrazene]]<br/>[[Diphosphene]]

'''Hydrazine''' is an [[inorganic compound]] with the [[chemical formula]] {{Chem2|N2H4|auto=yes}}. It is a simple [[pnictogen hydride]], and is a colourless flammable liquid with an [[ammonia]]-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, '''hydrazine hydrate''' ({{Chem2|N2H4*''x''H2O}}).

Hydrazine is mainly used as a [[foaming agent]] in preparing [[Polymeric foam|polymer foams]], but applications also include its uses as a [[precursor (chemistry)|precursor]] to [[pharmaceutical]]s and [[agrochemical]]s, as well as a long-term [[storable propellant]] for in-[[outer space|space]] spacecraft propulsion. Additionally, hydrazine is used in various [[rocket propellant|rocket fuels]] and to prepare the gas precursors used in [[air bags]]. Hydrazine is used within both nuclear and conventional electrical [[power plant]] steam cycles as an [[oxygen scavenger]] to control concentrations of dissolved oxygen in an effort to reduce corrosion.<ref>{{Cite journal |vauthors=Tsubakizaki S, Takada M, Gotou H, Mawatari K, Ishihara N, Kai R |date=2009 |title=Alternatives to Hydrazine in Water Treatment at Thermal Power Plants |url=https://www.mhi.co.jp/technology/review/pdf/e462/e462043.pdf |journal=Mitsubishi Heavy Industries Technical Review |volume=6 |issue=2 |pages=43–47}}</ref>

{{asof|2000}}, approximately 120,000 tons of hydrazine hydrate (corresponding to a 64% solution of hydrazine in water by weight) were manufactured worldwide per year.<ref name="Ullmann"/>

[[Hydrazines]] are a class of organic substances derived by replacing one or more hydrogen atoms in hydrazine by an organic group.<ref name="Ullmann"/>

==Etymology==

The nomenclature is a bi-valent form, with prefix ''hydr-'' used to indicate the presence of [[hydrogen]] atoms and suffix beginning with ''-az-'', from ''azote'', the French word for [[nitrogen]].

==Applications==

===Gas producers and propellants===

The largest use of hydrazine is as a precursor to [[blowing agent]]s. Specific compounds include [[azodicarbonamide]] and [[azobisisobutyronitrile]], which produce {{nowrap|100–200 mL}} of gas per gram of precursor. In a related application, [[sodium azide]], the gas-forming agent in [[air bags]], is produced from hydrazine by reaction with [[sodium nitrite]].<ref name=Ullmann/>

Hydrazine is also used as a long-term [[storable propellant]] on board [[outer space|space]] vehicles, such as the [[Dawn (spacecraft)#Propulsion system|''Dawn'']] mission to Ceres and Vesta, and to both reduce the concentration of dissolved oxygen in and control pH of water used in large industrial boilers. The [[General Dynamics F-16 Fighting Falcon|F-16]] fighter jet, [[Eurofighter Typhoon]],<ref>{{Cite journal |title=A Summary of NASA and USAF Hypergolic Propellant Related Spills and Fires |url=https://ntrs.nasa.gov/api/citations/20100038321/downloads/20100038321.pdf |journal=Kennedy Space Center}}</ref> [[Space Shuttle]], and [[Lockheed U-2|U-2]] spy plane use hydrazine to fuel their Emergency Start System in the event of an engine stall.<ref>{{Cite web |url=http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA065595 |title=Exhaust Gas Composition of the F-16 Emergency Power Unit |last1=Suggs |first1=HJ|last2=Luskus|first2=LJ|date=1979|publisher=[[United States Air Force|USAF]]|type=technical report |id=SAM-TR-79-2|archive-url=https://web.archive.org/web/20160304084802/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA065595 |archive-date=4 March 2016|access-date=23 Jan 2019 |last3=Kilian|first3=HJ|last4=Mokry|first4=JW}}</ref>

===Precursor to pesticides and pharmaceuticals===

[[Image:Fluconazole skeletal formula.svg|thumb|left|180 px|[[Fluconazole]], synthesized using hydrazine, is an [[antifungal]] medication.]]

Hydrazine is a precursor to several pharmaceuticals and pesticides. Often these applications involve conversion of hydrazine to [[Heterocyclic compound|heterocyclic rings]] such as [[pyrazole]]s and [[pyridazine]]s. Examples of commercialized bioactive [[Hydrazines|hydrazine derivatives]] include [[cefazolin]], [[rizatriptan]], [[anastrozole]], [[fluconazole]], metazachlor, metamitron, [[metribuzin]], [[paclobutrazol]], diclobutrazole, [[propiconazole]], [[hydrazine sulfate]],<ref name="OrgSynth"/> [[diimide]], [[triadimefon]],<ref name="Ullmann"/> and [[dibenzoylhydrazine]].

Hydrazine compounds can be effective as active ingredients in insecticides, miticides, [[nematicide]]s, fungicides, antiviral agents, attractants, herbicides, or plant growth regulators.<ref>{{Cite web|url=https://patents.google.com/patent/US5304657A/en|title=Hydrazine compounds useful as pesticides|last1=Toki|first1=T|last2=Koyanagi|first2=T|date=1994|type=US patent|others=Ishihara Sangyo Kaisha Ltd (original assignee)|id=US5304657A|last3=Yoshida|first3=K|last4=Yamamoto|first4=K|last5=Morita|first5=M}}</ref>

===Small-scale, niche, and research===

The Italian [[catalyst]] manufacturer Acta (chemical company) has proposed using hydrazine as an alternative to [[hydrogen]] in [[fuel cell]]s. The chief benefit of using hydrazine is that it can produce over 200 m[[watt|W]]/cm² more than a similar hydrogen cell without requiring (expensive) [[platinum]] catalysts.<ref name=":0">{{Cite news|url=https://www.theengineer.co.uk/liquid-asset-3/|title=Liquid asset|date=15 Jan 2008|work=[[The Engineer (UK magazine)|The Engineer]]|access-date=23 Jan 2019|publisher=Centaur Media plc}}</ref> Because the fuel is liquid at room temperature, it can be handled and stored more easily than hydrogen. By storing the hydrazine in a tank full of a double-bonded [[carbon]]-[[oxygen]] [[carbonyl]], the fuel reacts and forms a safe solid called [[hydrazone]]. By then flushing the tank with warm water, the liquid hydrazine hydrate is released. Hydrazine has a higher [[electromotive force]] of 1.56 [[volt|V]] compared to 1.23 V for hydrogen. Hydrazine breaks down in the cell to form [[nitrogen]] and [[hydrogen]] which bonds with oxygen, releasing water.<ref name=":0" /> Hydrazine was used in fuel cells manufactured by [[Allis-Chalmers|Allis-Chalmers Corp.]], including some that provided electric power in space satellites in the 1960s.

A mixture of 63% hydrazine, 32% [[hydrazine nitrate]] and 5% water is a standard propellant for experimental [[Bulk loaded liquid propellants|bulk-loaded liquid propellant artillery]]. The propellant mixture above is one of the most predictable and stable, with a flat pressure profile during firing. Misfires are usually caused by inadequate ignition. The movement of the shell after a mis-ignition causes a large bubble with a larger ignition surface area, and the greater rate of gas production causes very high pressure, sometimes including catastrophic tube failures (i.e. explosions).<ref name=":1">{{Cite web|url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a263143.pdf|archive-url=https://web.archive.org/web/20200307105240/https://apps.dtic.mil/dtic/tr/fulltext/u2/a263143.pdf|url-status=live|archive-date=March 7, 2020|title=A Review of the Bulk-Loaded Liquid Propellant Gun Program for Possible Relevance to the Electrothermal Chemical Propulsion Program|last1=Knapton|first1=JD|last2=Stobie|first2=IC|date=Mar 1993|publisher=Army Research Laboratory|id=[https://apps.dtic.mil/docs/citations/ADA263143 ADA263143]|last3=Elmore|first3=L}}</ref> From January–June 1991, the [[U.S. Army Research Laboratory]] conducted a review of early bulk-loaded liquid propellant gun programs for possible relevance to the electrothermal chemical propulsion program.<ref name=":1" />

The [[United States Air Force]] (USAF) regularly uses H-70, a 70% hydrazine 30% water mixture, in operations employing the [[General Dynamics F-16 Fighting Falcon|General Dynamics F-16 "Fighting Falcon"]] fighter aircraft and the [[Lockheed U-2|Lockheed U-2 "Dragon Lady"]] reconnaissance aircraft. The single jet engine F-16 utilizes hydrazine to power its Emergency Power Unit (EPU), which provides emergency electrical and hydraulic power in the event of an engine flame out. The EPU activates automatically, or manually by pilot control, in the event of loss of hydraulic pressure or electrical power in order to provide emergency flight controls. The single jet engine U-2 utilizes hydrazine to power its Emergency Starting System (ESS), which provides a highly reliable method to restart the engine in flight in the event of a stall.<ref>{{Cite web|url=https://www.robins.af.mil/Portals/59/documents/technicalorders/00-25-172.pdf?ver=2016-08-22-142719-060|title=Ground Servicing of Aircraft and Static Grounding/Bonding|date=13 Mar 2017|website=[[United States Air Force|USAF]]|type=technical manual|id=TO 00-25-172|access-date=23 Nov 2018}}</ref>

====Rocket fuel====

[[File:Hypergolic Fuel for MESSENGER.jpg|thumb|upright|[[Anhydrous]] (pure, not in solution) hydrazine being loaded into the ''[[MESSENGER]]'' space probe (orbital reconnaissance mission of the planet [[Mercury (planet)|Mercury]]). The technician is wearing a safety suit in overpressure with an external air supply.]]

Hydrazine was first used as a component in [[rocket fuel]]s during [[World War II]]. A 30% mix by weight with 57% [[methanol]] (named [[List of stoffs|M-Stoff]] in the German [[Luftwaffe]]) and 13% water was called [[C-Stoff]] by the Germans.<ref name=Clark2018>{{cite book |isbn = 978-0-8135-9918-2 |title = Ignition!: An Informal History of Liquid Rocket Propellants |last1 = Clark |first1 = John Drury |author-link=John Drury Clark |date = 23 May 2018 |publisher = Rutgers University Press |url=https://books.google.com/books?id=BdU4DwAAQBAJ&q=C-Stoff |pages=302}}</ref> The mixture was used to power the [[Messerschmitt Me 163#Me 163 B|Messerschmitt Me 163B]] rocket-powered fighter plane, in which the German [[high test peroxide]] ''[[T-Stoff]]'' was used as an oxidizer. Unmixed hydrazine was referred to as [[List of stoffs|B-Stoff]] by the Germans, a designation also used later for the ethanol/water fuel for the [[V-2 missile]].<ref>{{cite report |author1=T. W. Price|author2=D. D. Evans|date= |title=Technical Report 32-7227 The Status of Monopropellant Hydrazine Technology| url=https://ntrs.nasa.gov/api/citations/19680006875/downloads/19680006875.pdf|publisher=National Aeronautics and Space Administration (NASA) |page=1|access-date=22 February 2022}}</ref>

Hydrazine is used as a low-power [[monopropellant]] for the maneuvering (RCS/Reaction control system) thrusters of spacecraft, and was used to power the [[Space Shuttle]]'s auxiliary power units (APUs). In addition, mono-propellant hydrazine-fueled rocket engines are often used in terminal descent of spacecraft. Such engines were used on the [[Viking program]] landers in the 1970s as well as the Mars landers ''[[Phoenix (spacecraft)|Phoenix]]'' (May 2008), ''[[Curiosity rover|Curiosity]]'' (August 2012), and ''[[Perseverance (rover)|Perseverance]]'' (February 2021).

A mixture of hydrazine and [[red fuming nitric acid]] ({{chem2|HNO3 + N2H4}}) was used as liquid rocket fuel during the [[Soviet space program]], where it became known as "[[devil's venom]]" due to its highly dangerous nature.<ref>{{Cite web|url=http://www.spacesafetymagazine.com/space-disasters/nedelin-catastrophe/historys-launch-padfailures-nedelin-disaster-part-1/|title=The Nedelin Catastrophe, Part 1|date=28 October 2014|archive-url=https://archive.today/20220215233340/http://www.spacesafetymagazine.com/space-disasters/nedelin-catastrophe/historys-launch-padfailures-nedelin-disaster-part-1/|access-date=15 February 2022|archive-date=15 February 2022|url-status=live}}</ref>

In all hydrazine mono-propellant engines, the hydrazine is passed over a [[catalyst]] such as [[iridium]] metal supported by high-surface-area [[alumina]] (aluminium oxide), which causes it to decompose into [[ammonia]] ({{chem2|NH3}}), nitrogen gas ({{chem2|N2}}), and hydrogen ({{chem2|H2}}) gas according to the three following reactions:<ref name="Haws">{{cite journal|vauthors=Haws JL, Harden DG|date=1965|title=Thermodynamic Properties of Hydrazine|journal= Journal of Spacecraft and Rockets |volume=2|issue=6|pages=972–974|bibcode=1965JSpRo...2..972H|doi=10.2514/3.28327}}</ref>

: Reaction 1:&emsp;{{chem2|N2H4 → N2 + 2 H2}}

: Reaction 2:&emsp;{{chem2|3 N2H4 → 4 NH3 + N2}}

: Reaction 3:&emsp;{{chem2|4 NH3 + N2H4 → 3 N2 + 8 H2}}

The first two reactions are extremely [[exothermic]] (the catalyst chamber can reach 800&nbsp;°C in a matter of milliseconds,<ref name="Vieira">{{cite journal|vauthors=Vieira R, Pham-Huu C, Kellera N, Ledouxa MJ|year=2002|title=New carbon nanofiber/graphite felt composite for use as a catalyst support for hydrazine catalytic decomposition|journal=[[Chemical Communications|Chem. Comm.]]|volume=44|issue=9|pages=954–955|doi=10.1039/b202032g|pmid=12123065}}</ref>) and they produce large volumes of hot gas from a small volume of liquid,<ref name="Chen">{{cite journal|vauthors=Chen X, Zhang T, Xia L, Li T, Zheng M, Wu Z, Wang X, Wei Z, Xin Q, Li C|date=Apr 2002|title=Catalytic Decomposition of Hydrazine over Supported Molybdenum Nitride Catalysts in a Monopropellant Thruster|journal=[[Catalysis Letters]]|volume=79|pages=21–25|doi=10.1023/A:1015343922044|s2cid=92094908}}</ref> making hydrazine a fairly efficient thruster propellant with a vacuum [[specific impulse]] of about 220 seconds.<ref>{{Cite web|url=https://www.eso-io.com/my.logout.php3?errorcode=20|archive-url=https://web.archive.org/web/20080623224048/http://cs.astrium.eads.net/sp/SpacecraftPropulsion/MonopropellantThrusters.html|title=BIG-IP logout page|archive-date=June 23, 2008|website=www.eso-io.com|access-date=May 20, 2020}}</ref> Reaction 2 is the most exothermic, but produces a smaller number of molecules than that of reaction 1. Reaction 3 is [[endothermic]] and reverts the effect of reaction 2 back to the same effect as reaction 1 alone (lower temperature, greater number of molecules). The catalyst structure affects the proportion of the {{chem2|NH3}} that is dissociated in reaction 3; a higher temperature is desirable for rocket thrusters, while more molecules are desirable when the reactions are intended to produce greater quantities of gas.<ref>{{Cite journal |last1=Valera-Medina |first1=A |last2=Xiao |first2=H |last3=Owen-Jones |first3=M |last4=David |first4=W. I. F. |last5=Bowen |first5=P. J. |date=2018-11-01 |title=Ammonia for power |journal=Progress in Energy and Combustion Science |language=en|volume=69 |pages=63–102 |doi=10.1016/j.pecs.2018.07.001 |s2cid=106214840 |issn=0360-1285|doi-access=free}}</ref>

Since hydrazine is a solid below 2&nbsp;°C, it is not suitable as a general purpose rocket propellant for military applications. Other [[Hydrazines|variants of hydrazine]] that are used as rocket fuel are [[monomethylhydrazine]], {{chem2|CH3NHNH2}}, also known as MMH (melting point −52&nbsp;°C), and [[unsymmetrical dimethylhydrazine]], {{chem2|(CH3)2NNH2}}, also known as UDMH (melting point −57&nbsp;°C). These derivatives are used in two-component rocket fuels, often together with [[dinitrogen tetroxide]], {{chem2|N2O4}}. A 50:50 mixture by weight of hydrazine and UDMH was used in the engine of the service propulsion system of the [[Apollo command and service module]], both the ascent and descent engines of the [[Apollo Lunar Module]] and [[Titan II]] [[Intercontinental ballistic missile|ICBMs]] and is known as [[Aerozine 50]].<ref name=Clark2018/> These reactions are extremely exothermic, and the burning is also [[Hypergolic propellant|hypergolic]] (it starts burning without any external ignition).<ref name="Mitchell">{{cite journal |vauthors=Mitchell MC, Rakoff RW, Jobe TO, Sanchez DL, Wilson B |date=2007 |title=Thermodynamic analysis of equations of state for the monopropellant hydrazine |journal= Journal of Thermophysics and Heat Transfer |volume=21 |issue=1 |pages=243–246 |doi=10.2514/1.22798}}</ref>

In the fictional book [[The Martian (Weir_novel)|The Martian]] (also adapted to a [[The Martian (film)|feature film]]) the titular character uses an [[iridium]] catalyst to separate [[hydrogen]] gas from surplus hydrazine fuel, which he then burns to generate water for survival.

There are ongoing efforts in the aerospace industry to find a replacement for hydrazine, given its potential ban across the European Union.<ref>{{Cite web |date=2017-10-25 |title=Hydrazine ban could cost Europe's space industry billions |url=https://spacenews.com/hydrazine-ban-could-cost-europes-space-industry-billions/ |access-date=2022-08-19 |website=SpaceNews |language=en-US}}</ref><ref>{{Cite web |title=International research projects {{!}} Ministry of Business, Innovation & Employment |url=https://www.mbie.govt.nz/science-and-technology/space/nzspacetalk/international-research-projects/ |access-date=2022-08-19 |website=www.mbie.govt.nz}}</ref><ref>{{Cite web |last=Urban |first=Viktoria |date=2022-07-15 |title=Dawn Aerospace granted €1.4 million by EU for green propulsion technology |url=https://spacewatch.global/2022/07/dawn-aerospace-granted-e1-4-million-by-eu-for-green-propulsion-technology/ |access-date=2022-08-19 |website=SpaceWatch.Global |language=en-US}}</ref> Promising alternatives include [[nitrous oxide]]-based propellant combinations, with development being led by commercial companies [[Dawn Aerospace]], [[Impulse Space]],<ref>{{Cite web |last=Berger |first=Eric |date=2022-07-19 |title=Two companies join SpaceX in the race to Mars, with a launch possible in 2024 |url=https://arstechnica.com/science/2022/07/relativity-and-impulse-space-say-theyre-flying-to-mars-in-late-2024/ |access-date=2022-08-19 |website=Ars Technica |language=en-us}}</ref> and [[Launcher (company)|Launcher]].<ref>{{Cite web |date=2021-06-15 |title=Launcher to develop orbital transfer vehicle |url=https://spacenews.com/launcher-to-develop-orbital-transfer-vehicle/ |access-date=2022-08-19 |website=SpaceNews |language=en-US}}</ref> The first nitrous oxide-based system ever flown in space was by [[D-Orbit]] onboard their [[ION Satellite Carrier]] in 2021, using six Dawn Aerospace B20 thrusters.<ref>{{Cite web |title=Dawn Aerospace validates B20 Thrusters in space – Bits&Chips |url=https://bits-chips.nl/artikel/dawn-aerospace-validates-b20-thrusters-in-space/ |access-date=2022-08-19 |language=en-US}}</ref><ref>{{Cite web |title=Dawn B20 Thrusters Proven In Space |url=https://www.dawnaerospace.com/latest-news/b20-thrusters-proven-in-space |access-date=2022-08-19 |website=Dawn Aerospace |language=en-US}}</ref>

== Occupational hazards ==

=== Health effects ===

Potential routes of hydrazine exposure include dermal, ocular, inhalation and ingestion.<ref name=":3">{{Cite web |url=https://www.cdc.gov/niosh/docs/81-123/pdfs/0329.pdf |title=Occupational Safety and Health Guideline for Hydrazine—Potential Human Carcinogen |date=1988 |website=[[National Institute for Occupational Safety and Health|NIOSH]]|access-date=23 Nov 2018}}</ref>

Hydrazine exposure can cause skin irritation/contact dermatitis and burning, irritation to the eyes/nose/throat, nausea/vomiting, shortness of breath, pulmonary edema, headache, dizziness, central nervous system depression, lethargy, temporary blindness, seizures and coma. Exposure can also cause organ damage to the liver, kidneys and central nervous system.<ref name=":3" /><ref name=":2">{{Cite web |url=https://www.epa.gov/sites/production/files/2016-09/documents/hydrazine.pdf |title=Hydrazine 302-01-2 |website=[[United States Environmental Protection Agency|US EPA]] |access-date=23 Nov 2018}}</ref> Hydrazine is documented as a strong skin sensitizer with potential for cross-sensitization to hydrazine derivatives following initial exposure.<ref name=":4">{{Cite web |url=http://www.inchem.org/documents/hsg/hsg/hsg056.htm |title=International Programme on Chemical Safety—Health and Safety Guide No. 56—Hydrazine |date=1991 |website=IPCS INCHEM |publisher=[[World Health Organization|WHO]] |location=Geneva |access-date=24 Nov 2018}}</ref> In addition to occupational uses reviewed above, exposure to hydrazine is also possible in small amounts from tobacco smoke.<ref name=":2" />

The official U.S. guidance on hydrazine as a carcinogen is mixed but generally there is recognition of potential cancer-causing effects. The [[National Institute for Occupational Safety and Health|National Institute for Occupational Safety and Health (NIOSH)]] lists it as a "potential occupational carcinogen". The National Toxicology Program (NTP) finds it is "reasonably anticipated to be a human carcinogen". The [[American Conference of Governmental Industrial Hygienists|American Conference of Governmental Industrial Hygienists (ACGIH)]] grades hydrazine as "A3—confirmed animal carcinogen with unknown relevance to humans". The U.S. Environmental Protection Agency (EPA) grades it as "B2—a probable human carcinogen based on animal study evidence".<ref name=":5">{{Cite web |url=https://www.osha.gov/chemicaldata/chemResult.html?recNo=347 |title=Occupational Chemical Database—Hydrazine |website=www.osha.gov |publisher=[[Occupational Safety and Health Administration|OSHA]] |access-date=24 Nov 2018}}</ref>

The International Agency for Research on Cancer (IARC) rates hydrazine as "2A—probably carcinogenic to humans" with a positive association observed between hydrazine exposure and lung cancer.<ref name=":03">{{Cite web |url=https://monographs.iarc.fr/wp-content/uploads/2018/06/mono115-06.pdf |title=Hydrazine |date=Jun 2018 |publisher=[[International Agency for Research on Cancer|IARC]] |access-date=23 Nov 2018 |archive-date=26 November 2020 |archive-url=https://web.archive.org/web/20201126130626/https://monographs.iarc.fr/wp-content/uploads/2018/06/mono115-06.pdf }}</ref> Based on cohort and cross-sectional studies of occupational hydrazine exposure, a committee from the [[National Academy of Sciences|National Academies of Sciences]], Engineering and Medicine concluded that there is suggestive evidence of an association between hydrazine exposure and lung cancer, with insufficient evidence of association with cancer at other sites.<ref>{{Cite book |title=Gulf War and Health: Fuels, Combustion Products, and Propellants |last=Institute of Medicine |publisher=The National Academies Press |year=2005 |isbn=978-0-309-09527-3 |volume=3 |location=Washington, DC |page=347 |chapter=Ch. 9: Hydrazines and Nitric Acid |doi=10.17226/11180 |s2cid=228274601 }}</ref> The [[European Commission]]'s [[Scientific Committee on Occupational Exposure Limit Values|Scientific Committee on Occupational Exposure Limits]] (SCOEL) places hydrazine in carcinogen "group B—a genotoxic carcinogen". The genotoxic mechanism the committee cited references hydrazine's reaction with endogenous formaldehyde and formation of a DNA-methylating agent.<ref>{{Cite web |url=http://ec.europa.eu/social/BlobServlet?docId=6516&langId=en |title=Recommendation from the Scientific Committee on Occupational Exposure Limits for Hydrazine |date=Aug 2010 |website=European Commission |format=PDF|access-date=23 Nov 2018}}</ref>

In the event of a hydrazine exposure-related emergency, [[National Institute for Occupational Safety and Health|NIOSH]] recommends removing contaminated clothing immediately, washing skin with soap and water, and for eye exposure removing contact lenses and flushing eyes with water for at least 15 minutes. [[NIOSH]] also recommends anyone with potential hydrazine exposure to seek medical attention as soon as possible.<ref name=":3" /> There are no specific post-exposure laboratory or medical imaging recommendations, and the medical work-up may depend on the type and severity of symptoms. The [[World Health Organization]] (WHO) recommends potential exposures be treated symptomatically with special attention given to potential lung and liver damage. Past cases of hydrazine exposure have documented success with pyridoxine ([[vitamin B6]]) treatment.<ref name=":4" />

=== Occupational exposure limits ===

* [[National Institute for Occupational Safety and Health|NIOSH]] Recommended Exposure Limit (REL): 0.03 [[Parts-per notation|ppm]] (0.04&nbsp;mg/m³) 2-hour ceiling<ref name=":5" />

* [[Occupational Safety and Health Administration|OSHA]] Permissible Exposure Limit (PEL): 1 ppm (1.3&nbsp;mg/m³) 8-hour Time Weighted Average<ref name=":5" />

* [[American Conference of Governmental Industrial Hygienists|ACGIH]] Threshold Limit Value (TLV): 0.01 ppm (0.013&nbsp;mg/m³) 8-hour Time Weighted Average<ref name=":5" />

The odor threshold for hydrazine is 3.7 ppm, thus if a worker is able to smell an ammonia-like odor then they are likely over the exposure limit. However, this odor threshold varies greatly and should not be used to determine potentially hazardous exposures.<ref name=":12">{{Cite web |url=https://nj.gov/health/eoh/rtkweb/documents/fs/1006.pdf |title=Hazardous Substance Fact Sheet—Hydrazine |date=Nov 2009 |website=New Jersey Department of Public Health |access-date=23 Nov 2018}}</ref>

For aerospace personnel, the [[United States Air Force]] uses an emergency exposure guideline, developed by the [[National Academy of Sciences]] Committee on Toxicology, which is utilized for non-routine exposures of the general public and is called the Short-Term Public Emergency Exposure Guideline (SPEGL). The SPEGL, which does not apply to occupational exposures, is defined as the acceptable peak concentration for unpredicted, single, short-term emergency exposures of the general public and represents rare exposures in a worker's lifetime. For hydrazine the 1-hour SPEGL is 2 ppm, with a 24-hour SPEGL of 0.08 ppm.<ref name=":6">{{Cite web |url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/821003/FID177/pubs/af/48/afoshstd48-8/afoshstd48-8.pdf |title=Air Force Occupational Safety and Health (AFOSH) Standard 48-8 |date=1 Sep 1997 |website=[[United States Air Force|USAF]] |access-date=23 Nov 2018}}</ref>

=== Handling and medical surveillance ===

A complete surveillance programme for hydrazine should include systematic analysis of biologic monitoring, medical screening and morbidity/mortality information. The [[Centers for Disease Control and Prevention|CDC]] recommends surveillance summaries and education be provided for supervisors and workers. Pre-placement and periodic medical screening should be conducted with specific focus on potential effects of hydrazine upon functioning of the eyes, skin, liver, kidneys, hematopoietic, nervous and respiratory systems.<ref name=":3" />

Common controls used for hydrazine include process enclosure, local exhaust ventilation and [[personal protective equipment]] (PPE).<ref name=":3" /> Guidelines for hydrazine PPE include non-permeable gloves and clothing, indirect-vent splash resistant goggles, face shield and in some cases a respirator.<ref name=":12" /> The use of respirators for the handling of hydrazine should be the last resort as a method of controlling worker exposure. In cases where respirators are needed, proper respirator selection and a complete respiratory protection program consistent with [[Occupational Safety and Health Administration|OSHA]] guidelines should be implemented.<ref name=":3"/>

For [[United States Air Force|USAF]] personnel, Air Force Occupational Safety and Health (AFOSH) Standard 48-8, Attachment 8 reviews the considerations for occupational exposure to hydrazine in missile, aircraft and spacecraft systems. Specific guidance for exposure response includes mandatory emergency shower and eyewash stations and a process for decontaminating protective clothing. The guidance also assigns responsibilities and requirements for proper PPE, employee training, medical surveillance and emergency response.<ref name=":6" /> USAF bases requiring the use of hydrazine generally have specific base regulations governing local requirements for safe hydrazine use and emergency response.

==Molecular structure==

Hydrazine, {{chem2|H2N\sNH2}}, contains two amine groups {{chem2|NH2}} connected by a single bond between the two nitrogen atoms. Each {{chem2|N\sNH2}} subunit is pyramidal. The structure of the free molecules was determined by [[gas electron diffraction]] and [[microwave spectroscopy]]. The N–N single bond length is 1.447(2) [[Angstrom|Å]] (144.7(2) [[picometer|pm]]), the N-H distance is 1.015(2) [[Angstrom|Å]], the N-N-H angles are 106(2)° and 112(2)°, the H-N-H angle is 107°.<ref>{{Cite journal |last1=Kohata |first1=Kunio |last2=Fukuyama |first2=Tsutomu |last3=Kuchitsu |first3=Kozo |date=March 1982 |title=Molecular structure of hydrazine as studied by gas electron diffraction |journal=The Journal of Physical Chemistry |volume=86 |issue=5 |pages=602–606 |doi=10.1021/j100394a005 |issn=0022-3654}}</ref> The molecule adopts a [[Gauche effect|gauche conformation]] with a torsion angle of 91(2)° (dihedral angle between the planes containing the N-N bond and the bisectors of the H-N-H angles). The [[rotational barrier]] is twice that of [[ethane]]. These structural properties resemble those of gaseous [[hydrogen peroxide]], which adopts a "skewed" [[Linear alkane conformation|anticlinal]] conformation, and also experiences a strong rotational barrier.

The structure of solid hydrazine was determined by X-ray diffraction. In this phase the N-N bond has a length of 1.46 [[Angstrom|Å]] and the nearest non-bonded distances are 3.19, 3.25 and 3.30 [[Angstrom|Å]].<ref>{{Cite journal |last1=Collin |first1=R. L. |last2=Lipscomb |first2=W. N. |date=1951-01-01 |title=The crystal structure of hydrazine |journal=Acta Crystallographica |volume=4 |issue=1 |pages=10–14 |doi=10.1107/s0365110x51000027 |issn=0365-110X|doi-access=free |bibcode=1951AcCry...4...10C }}</ref>

==Synthesis and production==

Diverse synthetic pathways for hydrazine production have been developed.<ref name="Ullmann">{{Ullmann|doi=10.1002/14356007.a13_177 |title=Hydrazine |year=2001 |last1=Schirmann |first1=Jean-Pierre |last2=Bourdauducq |first2=Paul |isbn=3-527-30673-0}}</ref> The key step is the creation of the [[Nitrogen|N]]–N single bond. The many routes can be divided into those that use chlorine oxidants (and generate salt) and those that do not.

===Oxidation of ammonia via oxaziridines from peroxide===

Hydrazine can be synthesized from ammonia and hydrogen peroxide with a ketone catalyst, in a procedure called the [[Peroxide process]] (sometimes called Pechiney-Ugine-Kuhlmann process, the Atofina–PCUK cycle, or ketazine process).<ref name="Ullmann"/> The net reaction is:<ref>{{Cite book |url=https://www.elsevier.com/books/chemistry-of-petrochemical-processes/matar-ph-d/978-0-88415-315-3 |title=Chemistry of Petrochemical Processes |last1=Matar |first1=Sami |last2=Hatch |first2=Lewis F. |date=2001 |publisher=Gulf Professional Publishing |isbn=978-1-4933-0346-5 |edition=2nd |location=Burlington |page=148 |oclc=990470096 |via=Elsevier}}</ref>

:{{chem2|2 NH3 + H2O2 → N2H4 + 2 H2O}}

In this route, the ketone and ammonia first condense to give the [[imine]], which is oxidised by hydrogen peroxide to the [[oxaziridine]], a three-membered ring containing carbon, oxygen, and nitrogen. Next, the oxaziridine gives the [[hydrazone]] by [[ammonolysis|treatment with ammonia]], which process creates the nitrogen-nitrogen single bond. This hydrazone condenses with one more equivalent of ketone.

:[[File:Pechiney-Ugine-Kuhlmann process.png|506px]]

The resulting [[acetone azine|azine]] is hydrolyzed to give hydrazine and regenerate the ketone, [[methyl ethyl ketone]]:

:{{chem2|[[Methyl group|Me]]([[Ethyl group|Et]])C\dN\sN\dC(Et)Me + 2 H2O → 2 Me(Et)C\dO + N2H4}}

Unlike most other processes, this approach does not produce a salt as a by-product.<ref>{{Cite book |chapter-url=https://www.academia.edu/9511336 |title=Riegel's handbook of industrial chemistry |last1=Riegel |first1=Emil Raymond |last2=Kent |first2=James Albert |date=2003 |publisher=Springer Science & Business Media |isbn=978-0-306-47411-8 |edition=10th |location=New York |page=192 |chapter=Hydrazine |oclc=55023601 }}</ref>

===Chlorine-based oxidations===

The [[Olin Raschig process]], first announced in 1907, produces hydrazine from [[sodium hypochlorite]] (the active ingredient in many [[bleach]]es) and ammonia without the use of a ketone catalyst. This method relies on the reaction of [[monochloramine]] with [[ammonia]] to create the [[Nitrogen|N]]–N [[single bond]] as well as a [[hydrogen chloride]] byproduct:<ref name="OrgSynth">{{cite journal |vauthors=Adams R, Brown BK |year=1922 |title=Hydrazine Sulfate |journal=[[Organic Syntheses|Org. Synth.]] |volume=2 |page=37 |doi=10.15227/orgsyn.002.0037 |s2cid=221547391 }}</ref>

:{{chem2|NH2Cl + NH3 → N2H4 + HCl}}

Related to the Raschig process, [[urea]] can be oxidized instead of ammonia. Again sodium hypochlorite serves as the oxidant. The net reaction is shown:<ref>{{cite web |url=http://chemindustry.ru/Hydrazine.php |title=Hydrazine: Chemical product info |website=chemindustry.ru |archive-url=https://web.archive.org/web/20180122212817/http://chemindustry.ru/Hydrazine.php |archive-date=22 January 2018 |access-date=8 Jan 2007}}</ref>

:{{chem2|(NH2)2CO + NaOCl + 2 NaOH → N2H4 + H2O + NaCl + Na2CO3}}

The process generates significant by-products and is mainly practised in Asia.<ref name="Ullmann"/>

The [[Peroxide process#Bayer ketazine process|Bayer Ketazine Process]] is the predecessor to the peroxide process. It employs sodium hypochlorite as oxidant instead of hydrogen peroxide. Like all hypochlorite-based routes, this method produces an equivalent of salt for each equivalent of hydrazine.<ref name="Ullmann"/>

==Reactions==

===Acid-base behavior===

[[File:Sample of hydrazine hydrate.jpg|thumb|Hydrazine hydrate]]

Hydrazine forms a [[monohydrate]] {{chem2|N2H4*H2O}} that is denser (1.032 g/cm³) than the [[anhydrous]] form {{chem2|N2H4}} (1.021 g/cm³). Hydrazine has [[base (chemistry)|basic]] ([[alkali]]) chemical properties comparable to those of [[ammonia]]:<ref>{{cite book |title = Handbook of Chemistry and Physics |edition = 83rd |publisher = CRC Press |date = 2002}}</ref>

:{{chem2|N2H4 + H2O → [N2H5]+ + OH-}}, ''K''_b = 1.3 × 10⁻⁶, p''K''_b = 5.9

(for ammonia ''K''_b = 1.78 × 10⁻⁵)

It is difficult to diprotonate:<ref>{{Cite book |title=Inorganic chemistry |vauthors=Holleman AF, Wiberg E, Wiberg N|date=2001 |publisher=Academic Press |isbn=978-0-12-352651-9 |edition=1st Eng. |location=San Diego |oclc=813400418}}</ref>

:{{chem2|[N2H5]+ + H2O → [N2H6](2+) + OH-}}, ''K''_b = 8.4 × 10⁻¹⁶, p''K''_b = 15

Exposure to extremely strong bases or alkali metals generates deprotonated hydrazide salts. Most explode on exposure to air or moisture.<ref>{{Kirk-Othmer|title=Hydrazine and its derivatives|year=2004|author=Eugene&nbsp;F. Rothgery|doi=10.1002/0471238961.0825041819030809.a01.pub2}} </ref>

===Redox reactions===

Ideally, the combustion of hydrazine in oxygen produces nitrogen and water:

:{{chem2|N2H4 + O2 → N2 + 2 H2O}}

An excess of oxygen gives oxides of nitrogen, including [[nitrogen monoxide]] and [[nitrogen dioxide]]:

:{{chem2|N2H4 + 2 O2 → 2 NO + 2 H2O}}

:{{chem2|N2H4 + 3 O2 → 2 NO2 + 2 H2O}}

The heat of combustion of hydrazine in oxygen (air) is 19.41 MJ/kg (8345 BTU/lb).<ref>{{cite web |url=http://cameochemicals.noaa.gov/chris/HDZ.pdf |title=Hydrazine—Chemical Hazard Properties Table |date=1999 |website=NOAA.gov}}</ref>

Hydrazine is a convenient reductant because the by-products are typically nitrogen gas and water. This property makes it useful as an [[antioxidant]], an oxygen [[scavenger (chemistry)|scavenger]], and a [[corrosion inhibitor]] in water boilers and heating systems. It also directly reduces salts of less active metals (e.g., bismuth, arsenic, copper, mercury, silver, lead, platinum, and palladium) to the element.<ref>{{cite book|url=https://archive.org/details/cftri.2662nonaqueoussolven0000ludw/page/133/|page=133|title=Non-aqueous solvents|first1=Ludwig F.|last1=Audrieth|first2=Jacob|last2=Kleinberg|publisher=John Wiley & Sons|location=New York|year=1953|lccn=52-12057}}</ref> That property has commercial application in [[electroless nickel plating|electroless]] [[nickel]] plating and [[plutonium]] extraction from [[nuclear waste|nuclear reactor waste]]. Some colour photographic processes also use a weak solution of hydrazine as a stabilising wash, as it scavenges [[dye coupler]] and unreacted silver halides. Hydrazine is the most common and effective reducing agent used to convert [[graphene oxide]] (GO) to reduced graphene oxide (rGO) via hydrothermal treatment.<ref>{{cite journal |vauthors=Stankovich S, Dikin DA, Piner RD, Kohlhaas KA, Kleinhammes A, Jia Y, Wu Y, Nguyen ST, Ruoff RS |date=2007 |title=Synthesis of graphene-based nanosheets via chemical reduction of exfoliated graphite oxide |journal=[[Carbon (journal)|Carbon]] |volume=45 |issue=7 |pages=1558–1565 |doi=10.1016/j.carbon.2007.02.034|bibcode=2007Carbo..45.1558S |s2cid=14548921 }}</ref>

===Hydrazinium salts===

Hydrazine can be [[protonated]] to form various solid salts of the [[hydrazinium]] cation {{chem2|[N2H5]+}}, by treatment with mineral acids. A common salt is [[hydrazinium hydrogensulfate]], {{chem2|[N2H5]+[HSO4]-}}.<ref>{{cite web |url=http://hazard.com/msds/mf/baker/baker/files/h3633.htm |title=HYDRAZINE SULFATE |website=hazard.com |access-date=22 Jan 2019}}</ref> Hydrazinium hydrogensulfate was investigated as a treatment of cancer-induced [[cachexia]], but proved ineffective.<ref>{{cite journal |vauthors=Gagnon B, Bruera E |date=May 1998 |title=A review of the drug treatment of cachexia associated with cancer |journal=[[Drugs (journal)|Drugs]] |volume=55 |issue=5 |pages=675–88 |doi=10.2165/00003495-199855050-00005 |pmid=9585863 |s2cid=22180434}}</ref>

Double protonation gives the hydrazinium [[dication]] or hydrazinediium, {{chem2|[N2H6](2+)}}, of which various salts are known.<ref>{{cite web |url=http://www.easychem.org/en/subst-ref/?id=3969 |title=Diazanediium |website=CharChem |access-date=22 Jan 2019}}</ref>

===Organic chemistry===

Hydrazines are part of many [[organic synthesis|organic syntheses]], often those of practical significance in [[pharmaceutical]]s (see applications section), as well as in textile [[dye]]s and in photography.<ref name=Ullmann/>

Hydrazine is used in the [[Wolff–Kishner reduction]], a reaction that transforms the [[carbonyl]] group of a [[ketone]] into a [[methylene bridge]] (or an [[aldehyde]] into a [[methyl group]]) via a [[hydrazone]] intermediate. The production of the highly stable [[dinitrogen]] from the hydrazine derivative helps to drive the reaction.

Being bifunctional, with two amines, hydrazine is a key building block for the preparation of many heterocyclic compounds via condensation with a range of difunctional [[electrophiles]]. With [[2,4-pentanedione]], it condenses to give the [[3,5-Dimethylpyrazole|3,5-dimethylpyrazole]].<ref>{{Cite journal |vauthors=Wiley RH, Hexner PE |date=1951 |title=3,5-Dimethylpyrazole |journal=[[Organic Syntheses|Org. Synth.]] |volume=31 |page=43 |doi=10.15227/orgsyn.031.0043}}</ref> In the [[Einhorn-Brunner reaction]] hydrazines react with imides to give [[triazole]]s.

Being a good nucleophile, {{chem2|N2H4}} can attack sulfonyl halides and acyl halides.<ref>{{Cite journal |vauthors=Friedman L, Litle RL, Reichle WR |date=1960 |title=p-Toluenesulfonyl Hydrazide |journal=[[Organic Syntheses|Org. Synth.]] |volume=40 |page=93 |doi=10.15227/orgsyn.040.0093}}</ref> The [[tosyl]]hydrazine also forms hydrazones upon treatment with carbonyls.

Hydrazine is used to cleave ''N''-alkylated phthalimide derivatives. This scission reaction allows phthalimide anion to be used as amine precursor in the [[Gabriel synthesis]].<ref>{{Cite journal |vauthors=Weinshenker NM, Shen CM, Wong JY |date=1977 |title=Polymeric Carbodiimide. Preparation |journal=[[Organic Syntheses|Org. Synth.]] |volume=56 |page=95 |doi=10.15227/orgsyn.056.0095}}</ref>

====Hydrazone formation====

Illustrative of the condensation of hydrazine with a simple carbonyl is its reaction with acetone to give the [[acetone azine]]. The latter reacts further with hydrazine to yield [[acetone hydrazone]]:<ref>{{Cite journal |vauthors=Day AC, Whiting MC |date=1970 |title=Acetone Hydrazone |journal=Organic Syntheses |volume=50 |page=3 |doi=10.15227/orgsyn.050.0003}}</ref>

:{{chem2|2 (CH3)2CO + N2H4 → 2 H2O + ((CH3)2C\dN)2}}

:{{chem2|((CH3)2C\dN)2 + N2H4 → 2 (CH3)2C\dNNH2}}

The propanone azine is an intermediate in the Atofina-[[Pechiney–Ugine–Kuhlmann process|PCUK process]]. Direct [[alkylation]] of hydrazines with [[alkyl halides]] in the presence of base yields alkyl-substituted hydrazines, but the reaction is typically inefficient due to poor control on level of substitution (same as in ordinary [[amine]]s). The reduction of [[hydrazone]]s to hydrazines present a clean way to produce 1,1-dialkylated hydrazines.

In a related reaction, 2-cyanopyridines react with hydrazine to form amide hydrazides, which can be converted using [[diketone|1,2-diketones]] into [[triazine]]s.

===Biochemistry===

Hydrazine is the intermediate in the anaerobic oxidation of ammonia ([[anammox]]) process.<ref>{{cite journal |vauthors=Strous M, Jetten MS |date=2004 |title=Anaerobic Oxidation of Methane and Ammonium |journal=[[Annual Review of Microbiology|Annu Rev Microbiol]] |volume=58 |pages=99–117 |doi=10.1146/annurev.micro.58.030603.123605 |pmid=15487931|hdl=2066/60186 |hdl-access=free }}</ref> It is produced by some yeasts and the open ocean bacterium anammox (''[[Brocadia anammoxidans]]'').<ref>{{cite news |url=http://www.wildsingapore.com/news/20051112/051109-5.htm |title=Bacteria Eat Human Sewage, Produce Rocket Fuel |last=Handwerk |first=Brian |date=9 Nov 2005 |access-date=12 Nov 2007 |publisher=[[National Geographic Society|National Geographic]] |via=Wild Singapore}}</ref>

The [[false morel]] produces the poison [[gyromitrin]] which is an organic derivative of hydrazine that is converted to [[monomethylhydrazine]] by metabolic processes. Even the most popular edible "button" mushroom ''[[Agaricus bisporus]]'' produces organic hydrazine derivatives, including [[agaritine]], a [[Hydrazines|hydrazine derivative]] of an amino acid, and [[gyromitrin]].<ref>{{cite journal |vauthors=Hashida C, Hayashi K, Jie L, Haga S, Sakurai M, Shimizu H |date=1990 |title=[Quantities of agaritine in mushrooms (''Agaricus bisporus'') and the carcinogenicity of mushroom methanol extracts on the mouse bladder epithelium] |journal=Nippon Koshu Eisei Zasshi |language=ja |volume=37 |issue=6 |pages=400–5 |pmid=2132000}}</ref><ref>{{cite web |url=http://www.psms.org/sporeprints/sp338.html |title=Spore Prints #338 |veditors=Sieger AA |date=1 Jan 1998 |work=Bulletin of the Puget Sound Mycological Society |access-date=13 Oct 2008}}</ref>

==History==

The name "hydrazine" was coined by [[Emil Fischer]] in 1875; he was trying to produce organic compounds that consisted of mono-substituted hydrazine.<ref>{{Cite journal |vauthors=Fischer E |date=1875 |title=Über aromatische Hydrazinverbindungen |trans-title=On aromatic hydrazine compounds |url=https://gallica.bnf.fr/ark:/12148/bpt6k90680z/f596.image.langEN |journal=[[Berichte der Deutschen Chemischen Gesellschaft|Ber. Dtsch. Chem. Ges.]] |volume=8 |pages=589–594 |doi=10.1002/cber.187500801178}}</ref> By 1887, [[Theodor Curtius]] had produced hydrazine sulfate by treating organic diazides with dilute sulfuric acid; however, he was unable to obtain pure hydrazine, despite repeated efforts.<ref>{{Cite journal |vauthors=Curtius T |date=1887 |title=Über das Diamid (Hydrazin) |trans-title=On diamide (hydrazine) |url=https://gallica.bnf.fr/ark:/12148/bpt6k907102/f818.image.langEN |journal=[[Berichte der Deutschen Chemischen Gesellschaft|Ber. Dtsch. Chem. Ges.]] |volume=20 |pages=1632–1634 |doi=10.1002/cber.188702001368}}</ref><ref>{{Cite book |chapter-url=https://books.google.com/books?id=GHYMAAAAYAAJ&pg=PA27 |title=Journal für praktische Chemie |vauthors=Curtius T, Jay R |publisher=Verlag von Johann Ambrosius Barth |year=1889 |veditors=Erdmann OL |volume=147 |chapter=Diazo- und Azoverbindungen der Fettreihe. IV. Abhandlung. über das Hydrazin |trans-chapter=Diazo- and azo- compounds of alkanes. Fourth treatise. On hydrazine}} On p. 129, Curtius admits: "{{lang|de|''Das freie Diamid'' NH₂-NH₂ ''ist noch nicht analysiert worden''.|italic=unset}}" [Free hydrazine has not been analyzed yet.]</ref><ref>{{Cite book |title=Journal für praktische Chemie |vauthors=Curtius T, Schulz H |year=1890 |volume=150 |pages=521–549 |chapter=''Über Hydrazinehydrat und die Halogenverbindungen des Diammoniums'' |trans-chapter=On hydrazine hydrate and the halogen compounds of diammonium |chapter-url=https://gallica.bnf.fr/ark:/12148/bpt6k90790j/f527.image.langEN?lang=EN}}</ref> Pure anhydrous hydrazine was first prepared by the Dutch chemist [[Cornelis Adriaan Lobry van Troostenburg de Bruyn|Lobry de Bruyn]] in 1895.<ref>{{Cite journal |vauthors=Lobry de Bruyn CA |title=Sur l'hydrazine (diamide) libre |trans-title=On free hydrazine (diamide) |journal=[[Recueil des Travaux Chimiques des Pays-Bas|Recl. Trav. Chim. Pays-Bas]] |volume=13 |issue=8 |pages=433–440 |doi=10.1002/recl.18940130816 |year=1894}}</ref><ref>{{Cite journal |vauthors=Lobry de Bruyn CA |date=1895 |title=Sur l'hydrate d'hydrazine |trans-title=On the hydrate of hydrazine |journal=[[Recueil des Travaux Chimiques des Pays-Bas|Recl. Trav. Chim. Pays-Bas]] |volume=14 |issue=3 |pages=85–88 |doi=10.1002/recl.18950140302}}</ref><ref>{{Cite journal |vauthors=Lobry de Bruyn CA |date=1896 |title=L'hydrazine libre I |trans-title=Free hydrazine, Part 1 |journal=[[Recueil des Travaux Chimiques des Pays-Bas|Recl. Trav. Chim. Pays-Bas]] |language=en |volume=15 |issue=6 |pages=174–184 |doi=10.1002/recl.18960150606}}</ref>

*{{annotated link|Nitrous oxide fuel blend}}

*{{annotated link|USA-193}}

{{Reflist}}

* [http://www.princeton.edu/~orggroup/supergroup_pdf/rmatunasAGM5hydrazine.pdf The Late Show with Rob! Tonight's Special Guest: Hydrazine (PDF)]{{snd}}Robert Matunas

* [http://chemindustry.ru/Hydrazine.php Hydrazine{{snd}}chemical product info: properties, production, applications.]

* [https://web.archive.org/web/20120213081441/http://www.gasdetection.com/TECH/hydrazine.html Hydrazine toxicity]

* [https://www.cdc.gov/niosh/npg/npgd0329.html CDC{{snd}}NIOSH Pocket Guide to Chemical Hazards]

{{Nitrogen compounds}}

{{Authority control}}

{{Hydrides by group}}

[[Category:Hydrazines]]

[[Category:Bases (chemistry)]]

[[Category:IARC Group 2B carcinogens]]

[[Category:Chemical hazards]]