| -6.3 °C|
| 620 kg/m³|
1-Butene is an organic chemical compound, linear alpha-olefin (alkene), and one of the isomers of butene. The formula is CH3CH2CH=CH2. It is a highly flammable, easily condensed gas.
1-Butene is stable in itself but polymerizes readily to polybutene. Its main application is as a comonomer in the production of certain kinds of polyethylene, such as linear low-density polyethylene (LLDPE). It has also been used as a precursor to polypropylene resins, butylene oxide, and butanone.
1-Butene is produced either by separation from crude C4 refinery streams or from the dimerization of ethylene. It is distilled to give a very high-purity product. An estimated 12 billion kilograms were produced in 2011, usually as a mixture with isomeric butenes.