But-2-ene
| But-2-ene | |
|---|---|
| Other names | 2-Butene β-Butylene |
| Identifiers[note 1] | |
| InChI | InChI=1/C4H8/c1-3-4-2/h3-4H,1-2H3 |
| InChIKey | IAQRGUVFOMOMEM-UHFFFAOYAW |
| Standard InChI | InChI=1S/C4H8/c1-3-4-2/h3-4H,1-2H3 |
| Standard InChIKey | IAQRGUVFOMOMEM-UHFFFAOYSA-N |
| CAS number | [] |
| EC number | |
| RTECS | EM2932000 |
| ChemSpider | |
| Properties | |
| Chemical formula | C4H8 |
| Molar mass | 56.106 g/mol |
| Hazards[1] | |
| 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. | 324 ºC (615 ºF) |
| Related compounds | |
| Other butenes | But-1-ene (E)-But-2-ene (Z)-But-2-ene 2-Methylpropene |
| Other compounds | Butane Butyne |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
But-2-ene is an acyclic alkene with four carbon atoms. It is the simplest alkene to shown (E/Z)-isomerism (also known as cis/trans-isomerism).
It is a petrochemical, produced by the catalytic cracking of crude oil. Its main uses are in the production of gasoline (petrol) and butadiene,[2] although some but-2-ene is also used to produce the solvent butanone (methyl ethyl ketone, MEK) via hydration to butan-2-ol and oxidation.
The two isomers are extremely difficult to separate by distillation because of the proximity of their boiling points. Fortunately, separation is unnecessary in industrial usage, as both isomers behave similarly in the desired reactions. A typical industrial but-2-ene mixture is 70% (Z)-but-2-ene (cis-isomer) and 30% (E)-but-2-ene (trans-isomer). Butane and but-1-ene are common impurities, present at 1% or more in industrial mixtures, which also contain smaller amounts of isobutene, butadiene and butyne (ethylacetylene).[2]
Notes
- ↑ The CAS registry number 107-01-7 is sometimes incorrectly used for a mixture of but-1-ene and isomers of but-2-ene: the EC number 203-452-9 can correctly be used for such a mixture.
References
- ↑ 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.
- ↑ 2.0 2.1 2-Butene; SIDS Initial Assessment Report; Organisation for Economic Co-operation and Development, February 1995, <http://www.inchem.org/documents/sids/sids/107017.pdf>.
External links
 |
See also the corresponding article on Wikipedia. |
- SIDS Initial Assessment Report for 2-Butene from the Organisation for Economic Co-operation and Development (OECD)
(E)-But-2-ene
(Z)-But-2-ene
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