1-Butene (IUPAC name: But-1-ene, also known as 1-butylene) is the organic compound with the formula CH3CH2CH=CH2. It is a colorless gas. But-1-ene is an alkene easily condensed to give a colorless liquid. It is classified as a linear alpha-olefin (terminal alkene).[2] It is one of the isomersofbutene (butylene). It is a precursor to diverse products.
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| Names | |||
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| Preferred IUPAC name
But-1-ene[1] | |||
| Other names
Ethylethylene | |||
| Identifiers | |||
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3D model (JSmol) |
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| 1098262 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider |
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| ECHA InfoCard | 100.003.137 
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| EC Number |
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| 25205 | |||
PubChem CID |
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| UNII | |||
| UN number | 1012 | ||
CompTox Dashboard (EPA) |
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| Properties | |||
| C4H8 | |||
| Molar mass | 56.108 g·mol−1 | ||
| Appearance | Colorless Gas | ||
| Odor | slightly aromatic | ||
| Density | 0.62 g/cm3 | ||
| Melting point | −185.3 °C (−301.5 °F; 87.8 K) | ||
| Boiling point | −6.47 °C (20.35 °F; 266.68 K) | ||
| 0.221 g/100 mL | |||
| Solubility | soluble in alcohol, ether, benzene | ||
Refractive index (nD) |
1.3962 | ||
| Viscosity | 7.76 Pa | ||
| Hazards | |||
| GHS labelling: | |||
 
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| Danger | |||
| H220, H221, H280 | |||
| P210, P377, P381, P403, P410+P403 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | −79 °C; −110 °F; 194 K | ||
| 385 °C (725 °F; 658 K) | |||
| Explosive limits | 1.6-10% | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
Polymerization of but-1-ene gives polybutylene, which is used to make piping for domestic plumbing.[3] Another application is as a comonomer in the production of certain kinds of polyethylene, such as linear low-density polyethylene (LLDPE).[4] It has also been used as a precursor to polypropylene resins, butylene oxide, and butanone.[5]
But-1-ene is produced by separation from crude C4 refinery streams and by ethylene dimerization. The former affords a mixture of 1-and 2-butenes, while the latter affords only the terminal alkene.[6] It is distilled to give a very high purity product. An estimated 12 billion kilograms were produced in 2011.[7]
