2-Butene
IUPAC name	But-2-ene
Other names	β-Butylene
Identifiers
CAS number	107-01-7 Y
EC-number	203-452-9
RTECS number	EM2932000
SMILES	C(=CC)C
InChI	1/C4H8/c1-3-4-2/h3-4H,1-2H3
InChI key	IAQRGUVFOMOMEM-UHFFFAOYAW
ChemSpider ID	11719
Properties
Molecular formula	C4H8
Molar mass	56.106 g/mol
Hazards[1]
EU Index	601-012-00-4
EU classification	Extremely flammable (F+)
R-phrases	R12
S-phrases	(S2), S9, S16, S33
NFPA 704	4 1 0
Flash point	flammable gas
Autoignition temperature	324 ºC (615 ºF)
Related compounds
Related butenes	1-Butene cis-2-Butene trans-2-Butene Isobutene
Related compounds	Butane Butyne
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

2-Butene is an acyclic alkene with four carbon atoms. It is the simplest alkene to shown cis/trans-isomerism (also known as (E/Z)-isomerism); that is, it exists as two geometrical isomers cis-2-Butene ((Z)-2-butene) and trans-2-Butene ((E)-2-butene).

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 2-butene 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 (4°C for -cis- and 1°C for trans-^[3]). However, 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]

[edit] References

[edit] External links

• SIDS Initial Assessment Report for 2-Butene from the Organisation for Economic Co-operation and Development (OECD)

This article about an organic compound is a stub. You can help Wikipedia by expanding it. v • d • e