| Revision as of 14:04, 10 January 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,066 edits Saving copy of the {{chembox}} taken from revid 443830500 of page Triethylborane for the Chem/Drugbox validation project (updated: ''). |
Latest revision as of 00:58, 10 January 2025 edit Stickhandler (talk | contribs)Extended confirmed users7,547 edits →Turbojet engines: name mf1 |
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{{short description|Pyrophoric liquid}} |
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{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}} |
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{{chembox |
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{{Distinguish|triethyl borate}}{{chembox |
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| verifiedrevid = 413645687 |
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|verifiedrevid = 470614232 |
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| Name = Triethylborane |
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|Name = Triethylborane |
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| ImageFileL1_Ref = {{chemboximage|correct|??}} |
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|ImageFileL1_Ref = {{chemboximage|correct|??}} |
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| ImageFileL1 = Triethylborane.svg |
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|ImageFileL1 = Triethylborane.svg |
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|ImageNameL1 = Triethylborane |
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| ImageSizeL1 = 120px |
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| ImageNameL1 = Triethylborane |
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|ImageFileR1 = Triethylborane-3D-balls.png |
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|ImageNameR1 = Ball-and-stick model of triethylborane |
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| ImageFileR1 = Triethylborane-3D-balls.png |
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|PIN = Triethylborane |
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| ImageSizeR1 = 120px |
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|OtherNames = Triethylborine, triethylboron |
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| ImageNameR1 = Ball-and-stick model of triethylborane |
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|Section1={{Chembox Identifiers |
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| IUPACName = Triethylborane |
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|SMILES = B(CC)(CC)CC |
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| OtherNames = triethylborine, triethylboron |
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|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| Section1 = {{Chembox Identifiers |
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|ChemSpiderID = 7079 |
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| SMILES = B(CC)(CC)CC |
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|PubChem = 7357 |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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|InChI = 1/C6H15B/c1-4-7(5-2)6-3/h4-6H2,1-3H3 |
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| ChemSpiderID = 7079 |
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|InChIKey = LALRXNPLTWZJIJ-UHFFFAOYAU |
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| PubChem = 7357 |
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|StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
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| InChI = 1/C6H15B/c1-4-7(5-2)6-3/h4-6H2,1-3H3 |
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|StdInChI = 1S/C6H15B/c1-4-7(5-2)6-3/h4-6H2,1-3H3 |
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| InChIKey = LALRXNPLTWZJIJ-UHFFFAOYAU |
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| StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
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|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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|StdInChIKey = LALRXNPLTWZJIJ-UHFFFAOYSA-N |
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| StdInChI = 1S/C6H15B/c1-4-7(5-2)6-3/h4-6H2,1-3H3 |
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| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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|CASNo_Ref = {{cascite|correct|CAS}} |
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|CASNo = 97-94-9 |
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| StdInChIKey = LALRXNPLTWZJIJ-UHFFFAOYSA-N |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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|UNII_Ref = {{fdacite|correct|FDA}} |
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|UNII = Z3S980Z4P3 |
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| CASNo = 97-94-9 |
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| EINECS = 202-620-9 |
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|EINECS = 202-620-9 |
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| RTECS = |
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}} |
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| Section2 = {{Chembox Properties |
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| Formula = C<sub>6</sub>H<sub>15</sub>B |
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| MolarMass = 98.00 g/mol |
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| Appearance = Colorless to pale yellow liquid |
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| Density = 0.677 g/cm<sup>3</sup> |
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| Solubility = N/A, Highly reactive |
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| MeltingPtC = -93 |
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| BoilingPtC = 95 |
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| pKa = |
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| Viscosity = |
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}} |
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| Section3 = {{Chembox Structure |
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| MolShape = |
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}} |
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| Section7 = {{Chembox Hazards |
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| ExternalMSDS = |
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| MainHazards = Spontaneously flammable in air; causes burns |
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| FlashPt = |
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| Autoignition = -20 °C |
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| RPhrases = {{R11}} {{R14/15}} {{R17}} {{R19}} {{R34}} {{R35}} {{R36/37}} |
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| SPhrases = {{S6}} {{S7/8}} {{S16}} {{S33}} {{S36/37/39}} {{S43}}A {{S45}} {{S29}} |
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}} |
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| Section8 = {{Chembox Related |
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| OtherCpds = ]<br />]<br />]<br/>] |
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}} |
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}} |
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|Section2={{Chembox Properties |
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|Formula = {{chem2|(CH3CH2)3B}} |
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|MolarMass = 98.00 g/mol |
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|Appearance = Colorless liquid |
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|Density = 0.677 g/cm<sup>3</sup> |
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|Solubility = Not applicable; highly reactive |
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|MeltingPtC = -93 |
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|BoilingPtC = 95 |
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}} |
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|Section7={{Chembox Hazards |
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|ExternalSDS = |
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|MainHazards = Spontaneously flammable in air; causes burns |
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|NFPA-F = 4 |
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|NFPA-H = 3 |
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|NFPA-R = 4 |
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|NFPA-S = W |
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|FlashPt = < |
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|FlashPtC = -20 |
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|AutoignitionPtC = -20 |
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| GHSPictograms = {{GHS02}}{{GHS05}}{{GHS06}}{{GHS08}} |
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| GHSSignalWord = Danger |
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| HPhrases = {{H-phrases|225|250|301|314|330|360}} |
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| PPhrases = {{P-phrases|201|202|210|222|233|240|241|242|243|260|264|270|271|280|281|284|301+310|301+330+331|302+334|303+361+353|304+340|305+351+338|308+313|310|320|321|330|363|370+378|403+233|403+235|405|422|501}} |
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}} |
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|Section8={{Chembox Related |
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|OtherCompounds = {{Unbulleted list |
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|] |
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|] |
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|] |
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|] |
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'''Triethylborane''' ('''TEB'''), also called '''triethylboron''', is an ] (a compound with a B–C bond). It is a colorless ] liquid. Its chemical formula is {{chem2|(CH3CH2)3B}} or {{chem2|(C2H5)3B}}, abbreviated {{chem2|]3B}}. It is soluble in organic solvents ] and ]. |
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==Preparation and structure== |
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Triethylborane is prepared by the reaction of ] with ]:<ref name=Ullmann/> |
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:Et<sub>3</sub>Al + (MeO)<sub>3</sub>B → Et<sub>3</sub>B + (MeO)<sub>3</sub>Al |
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The molecule is monomeric, unlike H<sub>3</sub>B and Et<sub>3</sub>Al, which tend to dimerize. It has a planar BC<sub>3</sub> core.<ref name=Ullmann/> |
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==Applications== |
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===Turbojet engines=== |
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Triethylborane was used to ignite the ] fuel in the ] ]/] engines powering the ]<ref name=mf1>{{cite web| url = http://www.marchfield.org/sr71a.htm| title = Lockheed SR-71 Blackbird| accessdate = 2009-05-05| publisher = March Field Air Museum| url-status = dead| archiveurl = https://web.archive.org/web/20000304181849/http://www.marchfield.org/sr71a.htm| archivedate = 2000-03-04}}</ref> and its predecessor, the ]. Triethylborane is suitable because it ignites readily upon exposure to oxygen. It was chosen as an ignition method for reliability reasons, and in the case of the Blackbird, because JP-7 fuel has very low volatility and is difficult to ignite. Conventional ignition plugs posed a high risk of malfunction. Triethylborane was used to start each engine and to ignite the ]s.<ref name=sr71fm>{{cite web| url = http://www.sr-71.org/blackbird/manual/1/1-22.php| title = Lockheed SR-71 Blackbird Flight Manual| accessdate = 2011-01-26| publisher = www.sr-71.org| archive-date = 2011-02-02| archive-url = https://web.archive.org/web/20110202220020/http://www.sr-71.org/blackbird/manual/1/1-22.php| url-status = live}}</ref> |
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===Rocketry=== |
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Mixed with 10–15% ], it was used before lift-off to ignite the ] on the ] rocket.<ref>{{cite book| page = 86| title = The Saturn V F-1 Engine: Powering Apollo Into History| author =A. Young| publisher = Springer| year = 2008| isbn = 978-0-387-09629-2}}</ref> |
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The ] engines that power the ] ] rocket use a ]-triethylborane mixture (TEA-TEB) as a first- and second-stage ignitor.<ref> {{Webarchive|url=https://web.archive.org/web/20100530232910/http://www.spaceflightnow.com/tracking/index.html|date=May 30, 2010}}, '']'', accessed 2010-06-02, Quotation: "The flanges will link the rocket with ground storage tanks containing liquid oxygen, kerosene fuel, helium, gaseous nitrogen and the first stage ignitor source called triethylaluminum-triethylborane, better known as TEA-TEB."</ref> |
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The ] ] launch vehicle's Reaver engines are also ignited by a triethylaluminium-triethylborane mixture.<ref>{{Cite web |title=https://twitter.com/Firefly_Space/status/1090319933534334977 |url=https://twitter.com/Firefly_Space/status/1090319933534334977 |access-date=2023-02-05 |website=Twitter |language=en}}</ref> |
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===Organic chemistry=== |
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Industrially, triethylborane is used as an ] in ] reactions, where it is effective even at low temperatures.<ref name=Ullmann>{{cite encyclopedia|first1 = Robert J.|last1 = Brotherton|first2 = C. Joseph|last2 = Weber|first3 = Clarence R.|last3 = Guibert|first4 = John L.|last4 = Little|title = Boron Compounds|encyclopedia = ]|date = 15 June 2000|publisher = Wiley-VCH|doi = 10.1002/14356007.a04_309|isbn = 3-527-30673-0}}</ref> As an initiator, it can replace some ] compounds. |
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It reacts with metal ]s, yielding enoxytriethylborates that can be alkylated at the α-carbon atom of the ketone more selectively than in its absence. For example, the enolate from treating cyclohexanone with ] produces 2-allylcyclohexanone in 90% yield when triethylborane is present. Without it, the product mixture contains 43% of the mono-allylated product, 31% di-allylated cyclohexanones, and 28% unreacted starting material.<ref name = CrichBook>{{cite book|chapter-url = https://books.google.com/books?id=JEcSmEKtoT4C&pg=PT1847|series = Handbook of Reagents for Organic Synthesis|volume = 11|title = Reagents for Radical and Radical Ion Chemistry|editor-last = Crich|editor-first = David|year = 2008|publisher = ]|isbn = 978-0-470-06536-5|chapter = Enoxytriethylborates and Enoxydiethylboranes|access-date = 2019-01-27|archive-date = 2022-02-19|archive-url = https://web.archive.org/web/20220219194543/https://books.google.com/books?id=JEcSmEKtoT4C&pg=PT1847|url-status = live}}</ref> The choice of base and temperature influences whether the more or less stable enolate is produced, allowing control over the position of substituents. Starting from 2-], reacting with potassium hydride and triethylborane in THF at room temperature leads to the more substituted (and more stable) enolate, whilst reaction at −78 °C with ], {{chem|KN|2}} and triethylborane generates the less substituted (and less stable) enolate. After reaction with ] the former mixture gives 2,2-dimethylcyclohexanone in 90% yield while the latter produces 2,6-dimethylcyclohexanone in 93% yield.<ref name = CrichBook /><ref>{{cite journal|title = Highly regioselective generation of "thermodynamic" enolates and their direct characterization by NMR|first1 = Ei-ichi|last1 = Negishi|authorlink1 = Ei-ichi Negishi|first2 = Sugata|last2 = Chatterjee|journal = ]|volume = 24|issue = 13|year = 1983|pages = 1341–1344|doi = 10.1016/S0040-4039(00)81651-2}}</ref> The Et stands for ] {{chem2|CH3CH2\s}}. |
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It is used in the ] reaction for deoxygenation of alcohols. In combination with lithium tri-''tert''-butoxyaluminum hydride it cleaves ethers. For example, THF is converted, after hydrolysis, to ]. It also promotes certain variants of the ].<ref>{{cite encyclopedia|first1 = Yoshinori|last1 = Yamamoto|first2 = Takehiko|last2 = Yoshimitsu|first3 = John L.|last3 = Wood|authorlink3 = John L. Wood|first4 = Laura Nicole|last4 = Schacherer|title = Triethylborane|encyclopedia = ]|doi = 10.1002/047084289X.rt219.pub3|date = 15 March 2007|publisher = Wiley|isbn = 978-0-471-93623-7}}</ref> |
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Triethylborane is the precursor to the reducing agents lithium triethylborohydride ("]") and ].<ref>{{cite book|last1 = Binger|first1 = P.|last2 = Köster|first2 = R.| chapter=Sodium Triethylhydroborate, Sodium Tetraethylborate, and Sodium Triethyl-1-Propynylborate |title = Inorganic Syntheses|series = ]|year = 1974|volume = 15|pages = 136–141|doi = 10.1002/9780470132463.ch31|isbn = 978-0-470-13246-3}}</ref> |
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:MH + Et<sub>3</sub>B → MBHEt<sub>3</sub> (M = Li, Na) |
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Triethylborane reacts with ] to form diethyl(methoxy)borane, which is used as the chelating agent in the ] for the stereoselective generation of ''syn''-1,3-]s from β-hydroxyketones.<ref>{{cite journal|title = A Novel Method for the ''In situ'' Generation of Alkoxydialkylboranes and Their Use in the Selective Preparation of 1,3-''syn'' Diols|last1 = Chen|first1 = Kau-Ming|last2 = Gunderson|first2 = Karl G.|last3 = Hardtmann|first3 = Goetz E.|last4 = Prasad|first4 = Kapa|last5 = Repic|first5 = Oljan|last6 = Shapiro|first6 = Michael J.|journal = ]|year = 1987|volume = 16|issue = 10|pages = 1923–1926|doi-access = free|doi = 10.1246/cl.1987.1923}}</ref><ref>{{Cite book|first = Jaemoon|last = Yang|chapter-url = https://books.google.com/books?id=A_vUdr6ABGIC&pg=PA151|chapter = Diastereoselective ''Syn''-Reduction of β-Hydroxy Ketones|title = Six-Membered Transition States in Organic Synthesis|year = 2008|publisher = ]|pages = 151–155|isbn = 978-0-470-19904-6|access-date = 2019-01-27|archive-date = 2022-02-19|archive-url = https://web.archive.org/web/20220219194529/https://books.google.com/books?id=A_vUdr6ABGIC&pg=PA151|url-status = live}}</ref> |
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==Safety== |
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Triethylborane is strongly ], with an ] temperature of {{convert|−20|C}},<ref>{{Cite web |url=http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html |title=Fuels and Chemicals - Autoignition Temperatures |access-date=2017-08-26 |archive-date=2015-05-04 |archive-url=https://web.archive.org/web/20150504022056/http://www.engineeringtoolbox.com/fuels-ignition-temperatures-d_171.html |url-status=live }}</ref> burning with an apple-green flame characteristic for boron compounds. Thus, it is typically handled and stored using ]s. Triethylborane is also acutely toxic if swallowed, with an {{LD50}} of 235 mg/kg in rat test subjects.<ref>{{Cite web |url=https://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=257192&brand=ALDRICH&PageToGoToURL=https%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F257192%3Flang%3Den |title=Archived copy |access-date=2020-09-26 |archive-date=2022-02-19 |archive-url=https://web.archive.org/web/20220219194531/https://www.sigmaaldrich.com/US/en/sds/ALDRICH/257192 |url-status=live }}</ref> |
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==See also== |
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*] |
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*] |
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*] |
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==References== |
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{{Reflist}}{{Boron compounds}} |
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] |
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] |