Difference between revisions of "2-Methylpropene"
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| IUPACName = 2-Methylpropene | | IUPACName = 2-Methylpropene | ||
| − | | OtherNames = Isobutene<br> | + | | OtherNames = Isobutylene<br/>Isobutene<br/>γ-Butylene<br/>2-Methylpropylene |
| Section1 = {{Chembox Identifiers | | Section1 = {{Chembox Identifiers | ||
| + | | InChI = 1/C4H8/c1-4(2)3/h1H2,2-3H3 | ||
| + | | StdInChI = 1S/C4H8/c1-4(2)3/h1H2,2-3H3 | ||
| + | | InChIKey = VQTUBCCKSQIDNK-UHFFFAOYAW | ||
| + | | StdInChIKey = VQTUBCCKSQIDNK-UHFFFAOYSA-N | ||
| CASNo = 115-11-7 | | CASNo = 115-11-7 | ||
| CASNo_Ref = {{cascite}} | | CASNo_Ref = {{cascite}} | ||
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| PubChem = 8255 | | PubChem = 8255 | ||
| SMILES = CC(=C)C | | SMILES = CC(=C)C | ||
| − | |||
| RTECS = UD0890000 | | RTECS = UD0890000 | ||
}} | }} | ||
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}} | }} | ||
| Section7 = {{Chembox Hazards | | Section7 = {{Chembox Hazards | ||
| − | | Reference = <ref name="ICSC">{{ICSC-ref|1027|name=Isobutene|date=April 2000}}</ref> | + | | Reference = <ref>{{CLP Regulation|index=601-012-00-4|page=450}}</ref><ref name="ICSC">{{ICSC-ref|1027|name=Isobutene|date=April 2000}}</ref> |
| EUIndex = 601-012-00-4 | | EUIndex = 601-012-00-4 | ||
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| GHSPictograms = {{GHS02|Flam. Gas 1}}{{GHS04|Press. Gas}} | | GHSPictograms = {{GHS02|Flam. Gas 1}}{{GHS04|Press. Gas}} | ||
| GHSSignalWord = DANGER | | GHSSignalWord = DANGER | ||
| HPhrases = {{H-phrases|220}} | | HPhrases = {{H-phrases|220}} | ||
| PPhrases = {{P-phrases|210|377|381|403}} | | PPhrases = {{P-phrases|210|377|381|403}} | ||
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| − | |||
| − | |||
| − | |||
| FlashPt = flammable gas | | FlashPt = flammable gas | ||
| Autoignition = 465 °C (869 ºF) | | Autoignition = 465 °C (869 ºF) | ||
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}} | }} | ||
| Section8 = {{Chembox Related | | Section8 = {{Chembox Related | ||
| − | | OtherFunctn = [[1- | + | | OtherFunctn = [[But-1-ene]]<br/>[[(E)-But-2-ene|(''E'')-But-2-ene]]<br/>[[(Z)-But-2-ene|(''Z'')-But-2-ene]] |
| Function = [[butene]]s | | Function = [[butene]]s | ||
| OtherCpds = [[Isobutane]] | | OtherCpds = [[Isobutane]] | ||
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}} | }} | ||
| − | ''' | + | '''2-Methylpropene''' (or '''isobutylene''') is a [[hydrocarbon]] of significant industrial importance. It is a four-carbon branched [[alkene]] (olefin), one of the four [[isomers of butylene]]. At standard temperature and pressure it is a colorless flammable gas. |
==Uses== | ==Uses== | ||
| − | + | 2-Methylpropene is used as an intermediate in the production of a variety of products. It is reacted with [[methanol]] and [[ethanol]] in the manufacture of the gasoline oxygenates [[methyl tert-butyl ether]] (MTBE) and [[ethyl tert-butyl ether]] (ETBE), respectively. [[Alkylation]] with butane produces [[isooctane]], another fuel additive. 2-Methylpropene is also used in the production of [[methacrolein]]. [[Polymerization]] of isobutylene produces [[butyl rubber]] (polyisobutylene). Antioxidants such as [[butylated hydroxytoluene]] (BHT) and [[butylated hydroxyanisole]] (BHA) are produced by [[Friedel-Crafts alkylation]] of [[phenol]]s using 2-methylpropene. | |
==Manufacture== | ==Manufacture== | ||
| − | + | 2-Methylpropene can be isolated from refinery streams by reaction with [[sulfuric acid]], but the most common industrial method for its production is by [[catalysis|catalytic]] [[dehydrogenation]] of [[isobutane]].<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 2-methylpropene increased dramatically as the demand for oxygenates such as MTBE grew. Key manufacturers of this product are Texas Petrochemicals and Lyondell in North America. | |
==Safety== | ==Safety== | ||
| − | + | 2-Methylpropene 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"/> | |
==See also== | ==See also== | ||
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*{{SIDS|id=115117|name=Isobutylene|date=November 2003}} | *{{SIDS|id=115117|name=Isobutylene|date=November 2003}} | ||
| + | {{DEFAULTSORT:Methylpropene-2}} | ||
[[Category:Alkenes]] | [[Category:Alkenes]] | ||
{{Imported from Wikipedia|name=Isobutylene|id=311420873}} | {{Imported from Wikipedia|name=Isobutylene|id=311420873}} | ||
Latest revision as of 01:29, 2 September 2009
| 2-Methylpropene | |
|---|---|
 |
 |
| |
| IUPAC name | 2-Methylpropene |
| Other names | Isobutylene Isobutene γ-Butylene 2-Methylpropylene |
| Identifiers | |
| InChI | InChI=1/C4H8/c1-4(2)3/h1H2,2-3H3 |
| InChIKey | VQTUBCCKSQIDNK-UHFFFAOYAW |
| Standard InChI | InChI=1S/C4H8/c1-4(2)3/h1H2,2-3H3 |
| Standard InChIKey | VQTUBCCKSQIDNK-UHFFFAOYSA-N |
| CAS number | [] |
| EC number | |
| UN number | 1055 In Liquefied petroleum gas: 1075 |
| RTECS | UD0890000 |
| ChemSpider | |
| PubChem | |
| SMILES | |
| Properties[1] | |
| Molecular formula | C4H8 |
| Molar mass | 56.11 g mol−1 |
| Appearance | Colorless gas |
| Density | 0.5879 g/cm3, liquid |
| Melting point |
−140.3 ºC |
| Boiling point |
-6.9 °C, 266 K, 20 °F |
| Solubility in water | Insoluble |
| Hazards[2][3] | |
| EU index number | 601-012-00-4 |
| GHS pictograms |  
|
| GHS signal word | DANGER |
| GHS hazard statements | H220 |
| GHS precautionary statements | P210, P377, P381, P403 |
| Flash point | flammable gas |
| Autoignition temp. | 465 °C (869 ºF) |
| Explosive limits | 1.8–9.6% |
| Related compounds | |
| Other butenes | But-1-ene (E)-But-2-ene (Z)-But-2-ene |
| Other compounds | Isobutane |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
2-Methylpropene (or isobutylene) is a hydrocarbon of significant industrial importance. It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. At standard temperature and pressure it is a colorless flammable gas.
Uses
2-Methylpropene is used as an intermediate in the production of a variety of products. It is reacted with methanol and ethanol in the manufacture of the gasoline oxygenates methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE), respectively. Alkylation with butane produces isooctane, another fuel additive. 2-Methylpropene is also used in the production of methacrolein. Polymerization of isobutylene produces butyl rubber (polyisobutylene). Antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are produced by Friedel-Crafts alkylation of phenols using 2-methylpropene.
Manufacture
2-Methylpropene can be isolated from refinery streams by reaction with sulfuric acid, but the most common industrial method for its production is by catalytic dehydrogenation of isobutane.[4] In the 1990s, the production of 2-methylpropene increased dramatically as the demand for oxygenates such as MTBE grew. Key manufacturers of this product are Texas Petrochemicals and Lyondell in North America.
Safety
2-Methylpropene 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.[3]
See also
References
- ↑ The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 11th ed.; Merck, 1989. ISBN 091191028X, 5024.
- ↑ Index no. 601-012-00-4 of Annex VI, Part 3, to Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006. OJEU L353, 31.12.2008, pp 1–1355 at p 450.
- ↑ 3.0 3.1 Isobutene; International Chemical Safety Card 1027; International Labour Organization: Geneva, April 2000, <http://www.inchem.org/documents/icsc/icsc/eics1027.htm>
- ↑ Olah, George A.; Molnár, Árpád Hydrocarbon Chemistry; Wiley-Interscience. ISBN 978-0471417828.
External links
- International Chemical Safety Card 1027
- SIDS Initial Assessment Report for Isobutylene from the Organisation for Economic Co-operation and Development (OECD)
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This page was originally imported from Wikipedia, specifically this version of the article "Isobutylene". Please see the history page on Wikipedia for the original authors. This WikiChem article may have been modified since it was imported. It is licensed under the Creative Commons Attribution–Share Alike 3.0 Unported license. |
