| Revision as of 15:32, 5 April 2011 editWikitanvirBot (talk | contribs)144,145 editsm r2.7.1) (robot Adding: nl:Isobuteen← Previous edit |
Latest revision as of 19:14, 24 October 2024 edit undoSmokefoot (talk | contribs)Autopatrolled, Extended confirmed users, Pending changes reviewers, Rollbackers74,550 edits →Production: diisobutene |
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{{short description|1=Unsaturated hydrocarbon compound (H2C=C(CH3)2)}} |
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{{chembox |
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{{chembox |
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|Verifiedfields = changed |
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| verifiedrevid = 402129369 |
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|Watchedfields = changed |
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| ImageFileL1 = Isobutylene-2D-skeletal.png |
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|verifiedrevid = 451537760 |
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| ImageSizeL1 = 110px |
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|ImageFile1 = Isobutylene.svg |
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| ImageNameL1 = Skeletal formula |
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|ImageName1 = Skeletal formula of isobutylene |
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| ImageFileR1 = Isobutylene-3D-vdW.png |
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| ImageSizeR1 = 120px |
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|ImageSize1 = 120px |
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|ImageFileL2 = Isobutylene-3D-balls.png |
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| ImageNameR1 = Space-filling model |
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|ImageNameL2 = Ball-and-stick model of isobutylene |
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| ImageFile2 = Isobutylene-3D-balls.png |
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|ImageFileR2 = Isobutylene-3D-vdW.png |
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| ImageSize2 = 180px |
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| ImageName2 = Ball-and-stick model |
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|ImageNameR2 = Space-filling model of isobutylene |
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|PIN = 2-Methylprop-1-ene |
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| IUPACName = 2-Methylpropene |
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| OtherNames = Isobutene<br/>γ-Butylene<br/>2-Methylpropylene |
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|OtherNames = 2-Methylpropene<br />Isobutene<br/>γ-Butylene<br/>2-Methylpropylene<br />Methylpropene |
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| Section1 = {{Chembox Identifiers |
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|Section1={{Chembox Identifiers |
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| StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
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|StdInChI_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChI = 1S/C4H8/c1-4(2)3/h1H2,2-3H3 |
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|StdInChI = 1S/C4H8/c1-4(2)3/h1H2,2-3H3 |
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| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChIKey = VQTUBCCKSQIDNK-UHFFFAOYSA-N |
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|StdInChIKey = VQTUBCCKSQIDNK-UHFFFAOYSA-N |
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| CASNo = 115-11-7 |
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|CASNo = 115-11-7 |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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|CASNo_Ref = {{cascite|correct|CAS}} |
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| UNNumber = ]<br/>''In ]: ''] |
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|UNNumber = ]<br/>''In ]: ''] |
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| EINECS = 204-066-3 |
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|EINECS = 204-066-3 |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID = 7957 |
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|ChemSpiderID = 7957 |
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| PubChem = 8255 |
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|PubChem = 8255 |
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|ChEBI_Ref = {{ebicite|changed|EBI}} |
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| SMILES = CC(=C)C |
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|ChEBI = 43907 |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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|SMILES = CC(=C)C |
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| UNII = QA2LMR467H |
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|UNII_Ref = {{fdacite|correct|FDA}} |
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| InChI = 1/C4H8/c1-4(2)3/h1H2,2-3H3 |
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|UNII = QA2LMR467H |
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| RTECS = UD0890000 |
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|InChI = 1/C4H8/c1-4(2)3/h1H2,2-3H3 |
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}} |
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|RTECS = UD0890000 |
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| Section2 = {{Chembox Properties |
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| Reference = <ref>{{Merck11th|5024}}.</ref> |
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| C=4|H=8 |
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| MolarMass = 56.106 g/mol |
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| Appearance = Colorless gas |
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| Density = 0.5879 g/cm<sup>3</sup>, liquid |
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| MeltingPt = −140.3 ºC |
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| BoilingPtC = -6.9 |
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| Boiling_notes = |
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| Solubility = Insoluble |
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| SolubleOther = |
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| Solvent = |
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}} |
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| Section7 = {{Chembox Hazards |
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| Reference = <ref name="ICSC">{{ICSC-ref|1027|name=Isobutene|date=April 2000}}</ref> |
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| EUIndex = 601-012-00-4 |
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| EUClass = Extremely flammable ('''F+''') |
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| RPhrases = {{R12}} |
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| SPhrases = {{S2}}, {{S9}}, {{S16}}, {{S33}} |
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| GHSPictograms = {{GHS02|Flam. Gas 1}}{{GHS04|Press. Gas}} |
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| GHSSignalWord = DANGER |
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| HPhrases = {{H-phrases|220}} |
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| PPhrases = {{P-phrases|210|377|381|403}} |
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| NFPA-H = 1 |
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| NFPA-F = 4 |
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| NFPA-R = 0 |
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| NFPA-O = |
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| FlashPt = flammable gas |
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| Autoignition = 465 °C (869 ºF) |
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| ExploLimits = 1.8–9.6% |
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}} |
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| Section8 = {{Chembox Related |
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| OtherFunctn = ]<br/>]<br/>] |
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| Function = ]s |
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| OtherCpds = ] |
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}} |
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}} |
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}} |
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|Section2={{Chembox Properties |
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|Properties_ref = <ref>{{Merck11th|5024}}.</ref> |
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|C=4 | H=8 |
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|MolarMass = 56.106 g/mol |
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|Appearance = Colorless gas |
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|Density = 0.5879 g/cm<sup>3</sup>, liquid |
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|MeltingPtC = −140.3 |
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|BoilingPtC = -6.9 |
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|MagSus = -44.4·10<sup>−6</sup> cm<sup>3</sup>/mol }} |
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|Section7={{Chembox Hazards |
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|Hazards_ref = <ref name="ICSC">{{ICSC-ref|1027|name=Isobutene|date=April 2000}}</ref> |
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|GHSPictograms = {{GHS02|Flam. Gas 1}}{{GHS exclamation mark|Press. Gas}} |
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|GHSSignalWord = DANGER |
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|HPhrases = {{H-phrases|220}} |
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|PPhrases = {{P-phrases|210|377|381|403}} |
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|NFPA-H = 1 |
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|NFPA-F = 4 |
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|NFPA-R = 0 |
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|FlashPt = flammable gas |
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|AutoignitionPtC = 465 |
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|ExploLimits = 1.8–9.6% |
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}} |
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|Section8={{Chembox Related |
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|OtherFunction = ]<br/>]<br/>] |
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|OtherFunction_label = ]s |
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|OtherCompounds = ] |
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}} |
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}} |
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'''Isobutylene''' (or '''2-methylpropene''') is a ] with the ] {{chem2|(CH3)2C\dCH2}}. It is a four-carbon branched ] (olefin), one of the four ]. It is a colorless flammable gas, and is of considerable industrial value.<ref>{{Ullmann|last1=Geilen|first1=Frank M.A.|last2=Stochniol|first2=Guido|last3=Peitz|first3=Stephan|last4=Schulte-Koerne|first4=Ekkehard|title=Butenes|year=2014|doi=10.1002/14356007.a04_483.pub3}}</ref> |
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==Production== |
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Polymer and chemical grade isobutylene is typically obtained by dehydrating ] (TBA) or ] ] of ] (Catofin or similar processes).<ref>{{citation | title = Hydrocarbon Chemistry | first1 = George A. | last1 = Olah | author-link1 = George Andrew Olah | first2 = Árpád | last2 = Molnár | date = May 2003 | publisher = Wiley-Interscience | isbn = 978-0-471-41782-8}}.</ref> Gasoline additives ] (MTBE) and ] (ETBE), respectively, are produced by reacting ] or ] with isobutylene contained in butene streams from olefin steam crackers or refineries, or with isobutylene from dehydrated TBA. Isobutylene is not isolated from the olefin or refinery butene stream before the reaction, as separating the ethers from the remaining butenes is simpler. Isobutylene can also be produced in high purities by "back-cracking" MTBE or ETBE at high temperatures and then separating the isobutylene by distillation from methanol. |
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Isobutylene is a byproduct in the ] of ] to prepare ]:<ref name=KO>{{cite encyclopedia|title=Metathesis|encyclopedia=Kirk-Othmer Encyclopedia of Chemical Technology|author=Lionel Delaude |author2=Alfred F. Noels |publisher=Wiley}}</ref> |
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:(CH<sub>3</sub>)<sub>3</sub>C-CH=C(CH<sub>3</sub>)<sub>2</sub> + {{red|1=CH<sub>2</sub>=CH<sub>2</sub>}} → (CH<sub>3</sub>)<sub>3</sub>C-CH={{red|CH<sub>2</sub>}} + (CH<sub>3</sub>)<sub>2</sub>C={{red|CH<sub>2</sub>}} |
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'''Isobutylene''' (or 2-methylpropene) is a ] of significant industrial importance. It is a four-carbon branched ] (olefin), one of the four ]. At standard temperature and pressure it is a colorless flammable gas. |
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==Uses== |
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==Uses== |
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Isobutylene is used as an intermediate in the production of a variety of products. It is reacted with ] and ] in the manufacture of the gasoline oxygenates ] (MTBE) and ] (ETBE), respectively. ] with butane produces ], another fuel additive. Isobutylene is also used in the production of ]. ] of isobutylene produces ] (polyisobutylene). Antioxidants such as ] (BHT) and ] (BHA) are produced by ] of ]s using isobutylene. |
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Isobutylene is used in the production of a variety of products. It is alkylated with butane to produce ] or dimerized to diisobutylene (DIB) and then hydrogenated to make ], a fuel additive. Isobutylene is also used in the production of ]. ] of isobutylene produces ] (polyisobutylene or PIB). Antioxidants such as ] (BHT) and ] (BHA) are produced by ] of ]s with isobutylene. |
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] is produced commercially by amination of isobutylene using ] ]s:<ref name=Ullmann>{{Ullmann|doi=10.1002/14356007.a02_001|title=Amines, Aliphatic|year=2000|last1= Eller|first1=Karsten|last2=Henkes|first2=Erhard|last3=Rossbacher|first3=Roland|last4=Höke|first4=Hartmut|isbn=3527306730}}</ref> |
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==Manufacture== |
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:{{chem2 | NH3 + CH2\dC(CH3)2 -> H2NC(CH3)3 }} |
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Isobutylene can be isolated from refinery streams by reaction with ], but the most common industrial method for its production is by ] ] of ].<ref>{{citation | title = Hydrocarbon Chemistry | first1 = George A. | last1 = Olah | authorlink1 = George Andrew Olah | first2 = Árpád | last2 = Molnár | publisher = Wiley-Interscience | isbn = 978-0471417828}}.</ref> In the 1990s, the production of isobutylene increased dramatically as the demand for oxygenates such as MTBE grew. Key manufacturers of this product are Texas Petrochemicals(TPC Group) and Lyondell in North America. |
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Applications are found in the calibration of ]s. |
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==Safety== |
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==Safety== |
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Isobutylene is a highly flammable gas. |
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Isobutylene is a highly flammable gas and presents an explosion danger. Usually stored as a compressed gas, if released it may produce an oxygen-deficient atmosphere that presents an asphyxiation hazard.<ref name="ICSC"/> |
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==See also== |
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==See also== |
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==References== |
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==References== |
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*{{SIDS|id=115117|name=Isobutylene|date=November 2003}} |
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*{{SIDS|id=115117|name=Isobutylene|date=November 2003}} |
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