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Unsymmetrical dimethylhydrazine
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<h2 id="synthesis">Synthesis</h2> <p>In 1875, UDMH was first prepared by <a href="/facts/Emil_Fischer/5wxbfBtu">Emil Fischer</a>, who discovered and named the class of <a href="/facts/Hydrazines/3LTsArMQ">hydrazines</a>, by reducing <a href="/facts/N-Nitrosodimethylamine/cTSmj134">N-Nitrosodimethylamine</a> with zinc in boiling <a href="/facts/Acetic_acid/uyBKA2Pd">acetic acid</a>.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a><a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> Fischer's student <a href="/facts/Edward_Renouf_(chemist)/PS02bdPV">Edward Renouf</a> later studied UDMH more extensively as part of his doctoral dissertation. Other historical lab routes include <a href="/facts/Methylation/EvDMWVW5">methylation</a> of <a href="/facts/Hydrazine/G7P5ITzU">hydrazine</a>, reduction of nitrodimethylamine and <a href="/facts/Amination/M9LurC2g">amination</a> of <a href="/facts/Dimethylamine/6ehYB5m0">dimethylamine</a> with aminopersulfuric acid.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> </p><p>UDMH is produced industrially by two routes.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> Based on the <a href="/facts/Olin_Raschig_process/uzKjF6Bb">Olin Raschig process</a>, one method involves reaction of <a href="/facts/Monochloramine/NI4tsT8m">monochloramine</a> with <a href="/facts/Dimethylamine/6ehYB5m0">dimethylamine</a> giving 1,1-dimethylhydrazinium chloride: </p> (CH3)2NH + NH2Cl → (CH3)2NNH2 ⋅ HCl <p>In the presence of suitable catalysts, acetylhydrazine can be N-dimethylated using <a href="/facts/Formaldehyde/Ck8RLfqk">formaldehyde</a> and hydrogen to give the N,N-dimethyl-N'-acetylhydrazine, which can subsequently be hydrolyzed: </p> CH3C(O)NHNH2 + 2CH2O + 2H2 → CH3C(O)NHN(CH3)2 + 2H2O CH3C(O)NHN(CH3)2 + H2O → CH3COOH + H2NN(CH3)2 <h2 id="uses">Uses</h2> <p>UDMH is often used in <a href="/facts/Hypergolic/p0Goa3rn">hypergolic</a> <a href="/facts/Rocket_fuel/IyFhQEA2">rocket fuels</a> as a <a href="/facts/Bipropellant/s0KadvqW">bipropellant</a> in combination with the oxidizer <a href="/facts/Nitrogen_tetroxide/01WfnHJh">nitrogen tetroxide</a> and less frequently with <a href="/facts/IRFNA/nPLqRxdo">IRFNA</a> (inhibited red fuming nitric acid) or <a href="/facts/Liquid_oxygen/qnI0KDTb">liquid oxygen</a>.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> UDMH is a derivative of <a href="/facts/Hydrazine/G7P5ITzU">hydrazine</a> and is sometimes referred to as a hydrazine. As a fuel, it is described in specification MIL-PRF-25604 in the United States.<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p><p>UDMH is stable and can be kept loaded in rocket fuel systems for long periods, which makes it appealing for use in many <a href="/facts/Liquid_rocket/TAonrVDn">liquid rocket</a> engines, despite its cost. In some applications, such as the OMS in the <a href="/facts/Space_Shuttle/7BoyetEv">Space Shuttle</a> or <a href="/facts/Orbital_maneuvering_system/HAlEFRSJ">maneuvering engines</a>, <a href="/facts/Monomethylhydrazine/2DPIl19F">monomethylhydrazine</a> is used instead due to its slightly higher <a href="/facts/Specific_impulse/JKGgw2I4">specific impulse</a>. In some kerosene-fueled rockets, UDMH functions as a starter fuel to start combustion and warm the rocket engine prior to switching to kerosene. </p><p>UDMH has higher stability than hydrazine, especially at elevated temperatures, and can be used as its replacement or together in a mixture. UDMH is used in many European, Russian, Indian, and Chinese rocket designs. The Russian <a href="/facts/UR-100/3WpHtj8H">SS-11 Sego</a> (aka 8K84) ICBM, <a href="/facts/UR-100N/D9mDCMFp">SS-19 Stiletto</a> (aka 15A30) ICBM, <a href="/facts/Proton_(rocket)/susmVN0U">Proton</a>, <a href="/facts/Kosmos-3M/AVHjqXC9">Kosmos-3M</a>, <a href="/facts/R-29RMU2_Layner/2NLfDE9l">R-29RMU2 Layner</a>, <a href="/facts/R-36M/ga1aBeDt">R-36M</a>, <a href="/facts/Rokot/xXx9Gzg7">Rokot</a> (based on 15A30) and the Chinese <a href="/facts/Long_March_2/15Vmhlvn">Long March 2</a> are the most notable users of UDMH (which is referred to as "heptyl" (codename from <a href="/facts/USSR/m7wWsPto">Soviet era</a>) by Russian engineers<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a>). The <a href="/facts/Titan_(rocket_family)/sTTkEDps">Titan</a>, <a href="/facts/Geosynchronous_Satellite_Launch_Vehicle/PBneb7NS">GSLV</a>, and <a href="/facts/Delta_rocket/gQH4EUYB">Delta rocket</a> families use a mixture of 50% hydrazine and 50% UDMH, called <a href="/facts/Aerozine_50/WPBKUnMV">Aerozine 50</a>, in different stages.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a> There is speculation that it is the fuel used in the ballistic missiles that North Korea has developed and tested in 2017.<a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> </p> <h2 id="safety">Safety</h2> <p>Hydrazine and its methyl derivatives are toxic but <a href="/facts/LD50/PSTer8Wv">LD50</a> values have not been reported.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> It is a precursor to <a href="/facts/Dimethylnitrosamine/cTSmj134">dimethylnitrosamine</a>, which is carcinogenic.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a> According to scientific data, usage of UDMH in rockets at <a href="/facts/Baikonur_Cosmodrome/sk16LwcH">Baikonur Cosmodrome</a> has had adverse effects on the environment.<a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> One such instance was the <a href="/facts/Nedelin_catastrophe/flEozlmy">Nedelin catastrophe</a> in 1960 when UDMH and <a href="/facts/Dinitrogen_tetroxide/01WfnHJh">dinitrogen tetroxide</a> leaked from a rocket after an explosion and killed a number of bystanders through burn injuries and its toxicity. </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Aerozine_50/WPBKUnMV">Aerozine 50</a></li> <li><a href="/facts/C-Stoff/eM4cQruo">C-Stoff</a></li> <li><a href="/facts/Devil%27s_venom/jCJYMyAb">Devil's venom</a></li> <li><a href="/facts/UH_25/nc61HvRb">UH 25</a></li></ul> <h2 id="further-reading">Further reading</h2> <ul><li>Schmidt, Eckart W. (2022). "Unsymmetrical Dimethylhydrazine". <i>Dimethylhydrazines</i>. <i>Encyclopedia of Liquid Fuels</i>. De Gruyter. pp. 1333–1562. <a href="/facts/Doi_(identifier)/muM9Etpq">doi</a>:<a href="https://doi.org/10.1515%2F9783110750287-016">10.1515/9783110750287-016</a>. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-11-075028-7.</li></ul> <h2 id="external-links">External links</h2> <ul><li><a href="https://web.archive.org/web/20030207030254/http://www.astronautix.com/props/n2o4udmh.htm">Encyclopedia Astronautica</a></li> <li><a href="https://www.cdc.gov/niosh/npg/npgd0227.html">CDC – NIOSH Pocket Guide to Chemical Hazards</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Semenkov, Ivan; Koroleva, Tatyana (1 December 2022). "Review on the environmental impact of emissions from space launches: a case study for areas affected by the Russian space programme". Environmental Science and Pollution Research. 29 (60): 89807–89822. Bibcode:2022ESPR...2989807S. doi:10.1007/s11356-022-23888-8. ISSN 1614-7499. PMID 36346528. S2CID 253396676. <a href="https://doi.org/10.1007/s11356-022-23888-8" target="_blank">https://doi.org/10.1007/s11356-022-23888-8</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Schirmann, Jean-Pierre; Bourdauducq, Paul (2001). "Hydrazine". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_177. ISBN 3-527-30673-0. <a href="3-527-30673-0" target="_blank">3-527-30673-0</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Aleksey Milyushkin, Anastasia Karnaeva (2023). "Unsymmetrical dimethylhydrazine transformation products: A review". Science of the Total Environment. 891: 164367. Bibcode:2023ScTEn.89164367M. doi:10.1016/j.scitotenv.2023.164367. PMID 37236454. S2CID 258899003. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Ul'yanovskii, Nikolay V.; Lakhmanov, Dmitry E.; Pikovskoi, Ilya I.; Falev, Danil I.; Popov, Mark S.; Kozhevnikov, Alexander Yu.; Kosyakov, Dmitry S. (15 July 2020). "Migration and transformation of 1,1-dimethylhydrazine in peat bog soil of rocket stage fall site in Russian North". Science of the Total Environment. 726: 138483. Bibcode:2020ScTEn.72638483U. doi:10.1016/j.scitotenv.2020.138483. ISSN 0048-9697. PMID 32315849. S2CID 216073493. <a href="https://www.sciencedirect.com/science/article/pii/S0048969720319963" target="_blank">https://www.sciencedirect.com/science/article/pii/S0048969720319963</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Koroleva, T. V.; Semenkov, I. N.; Lednev, S. A.; Soldatova, O. S. (1 February 2023). "Unsymmetrical Dimethylhydrazine (UDMH) and Its Transformation Products in Soils: A Review of the Sources, Detection, Behavior, Toxicity, and Remediation of Polluted Territories". Eurasian Soil Science. 56 (2): 210–225. Bibcode:2023EurSS..56..210K. doi:10.1134/S1064229322602001. ISSN 1556-195X. S2CID 257903133. <a href="https://doi.org/10.1134/S1064229322602001" target="_blank">https://doi.org/10.1134/S1064229322602001</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>Horst Kunz (2002). "Emil Fischer – Unequalled Classicist, Master of Organic Chemistry Research, and Inspired Trailblazer of Biological Chemistry". Angewandte Chemie International Edition. 41 (23): 4439–4451. doi:10.1002/1521-3773(20021202)41:23<4439::AID-ANIE4439>3.0.CO;2-6. PMID 12458504. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>Fischer, Emil (July 1875). "Ueber die Hydrazinverbindungen der Fettreihe". Berichte der deutschen chemischen Gesellschaft. 8 (2): 1587–1590. doi:10.1002/cber.187500802203. ISSN 0365-9496. <a href="https://books.google.com/books?id=6JdDAQAAMAAJ&pg=PA111" target="_blank">https://books.google.com/books?id=6JdDAQAAMAAJ&pg=PA111</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>"Organic Syntheses Procedure". orgsyn.org. Retrieved 2 November 2024. <a href="https://orgsyn.org/demo.aspx?prep=CV2P0211" target="_blank">https://orgsyn.org/demo.aspx?prep=CV2P0211</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Schirmann, Jean-Pierre; Bourdauducq, Paul (2001). "Hydrazine". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a13_177. ISBN 3-527-30673-0. <a href="3-527-30673-0" target="_blank">3-527-30673-0</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Semenkov, Ivan; Koroleva, Tatyana (1 December 2022). "Review on the environmental impact of emissions from space launches: a case study for areas affected by the Russian space programme". Environmental Science and Pollution Research. 29 (60): 89807–89822. Bibcode:2022ESPR...2989807S. doi:10.1007/s11356-022-23888-8. ISSN 1614-7499. PMID 36346528. S2CID 253396676. <a href="https://doi.org/10.1007/s11356-022-23888-8" target="_blank">https://doi.org/10.1007/s11356-022-23888-8</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>"Performance Specification Propellant, uns-Dimethylhydrazine (MIL-PRF-25604F)". ASSIST Database Quicksearch. 11 March 2014. Retrieved 26 May 2020. <a href="https://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=18058" target="_blank">https://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=18058</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>"Following Russian rocket explosion, experts warn of 'major contamination'". 2 July 2013. <a href="https://www.theverge.com/2013/7/2/4487096/russian-rocket-explosion-proton-heptyl-contamination" target="_blank">https://www.theverge.com/2013/7/2/4487096/russian-rocket-explosion-proton-heptyl-contamination</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Clark, John D. (1972). Ignition! An Informal History of Liquid Rocket Propellants. Rutgers University Press. p. 45. ISBN 0-8135-0725-1. <a href="0-8135-0725-1" target="_blank">0-8135-0725-1</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Broad, William J.; Sanger, David E. (17 September 2017). "The Rare, Potent Fuel Powering North Korea's Weapons". The New York Times. <a href="https://www.nytimes.com/2017/09/17/world/asia/north-korea-rocket-fuel-missiles.html" target="_blank">https://www.nytimes.com/2017/09/17/world/asia/north-korea-rocket-fuel-missiles.html</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>"unsym-Dimethylhydrazine Safedy data" (4 ed.). Archived from the original on 6 July 2018. Retrieved 23 January 2018. <a href="https://web.archive.org/web/20180706161800/https://www.fishersci.com/shop/msdsproxy?productName=AC116320100&productDescription=UNSYM-DIMETHYLHYDRAZINE%252C+10ML&catNo=AC116320100&vendorId=VN00032119&storeId=10652" target="_blank">https://web.archive.org/web/20180706161800/https://www.fishersci.com/shop/msdsproxy?productName=AC116320100&productDescription=UNSYM-DIMETHYLHYDRAZINE%252C+10ML&catNo=AC116320100&vendorId=VN00032119&storeId=10652</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Gangadhar Choudhary, Hugh Hansen (1998). "Human health perspective of environmental exposure to hydrazines: A review". Chemosphere. 37 (5): 801–843. Bibcode:1998Chmsp..37..801C. doi:10.1016/S0045-6535(98)00088-5. PMID 9717244. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>Abdrazak, P. Kh; Musa, K. Sh (21 June 2015). "The impact of the cosmodrome 'Baikonur' on the environment and human health". International Journal of Biology and Chemistry. 8 (1): 26–29. doi:10.26577/2218-7979-2015-8-1-26-29. Archived from the original on 8 August 2016. Retrieved 2 August 2016 – via ijbch.kaznu.kz. <a href="http://ijbch.kaznu.kz/index.php/kaznu/article/view/172" target="_blank">http://ijbch.kaznu.kz/index.php/kaznu/article/view/172</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> </ol>