Pentenes are

alkene In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, a ...

s with the chemical formula . Each contains one double bond within its molecular structure. Six different compounds are in this class, differing from each other by whether the carbon atoms are attached linearly or in a branched structure, and whether the double bond has a ''cis'' or ''trans'' form.

Straight-chain isomers

1-Pentene is an

alpha-olefin In organic chemistry, alpha-olefins (or α-olefins) are a family of organic compounds which are alkenes (also known as olefins) with a chemical formula , distinguished by having a double bond at the primary or alpha (α) position.''Petrochemical ...

. Most often, 1-pentene is made as a byproduct of catalytic or

thermal cracking In petrochemistry, petroleum geology and organic chemistry, cracking is the process whereby complex organic molecules such as kerogens or long-chain hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of ...

of petroleum, or during production of

ethylene Ethylene ( IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene ...

and propylene via thermal cracking of hydrocarbon fractions. The only commercial manufacturer of 1-pentene is Sasol Ltd, where it is separated from crude made by the Fischer–Tropsch process. 2-Pentene has two geometric isomers, ''cis''-2-pentene and ''trans''-2-pentene. ''Cis''-2-Pentene is used in olefin metathesis.

Branched-chain isomers

The branched isomers are 2-methylbut-1-ene, 3-methylbut-1-ene (isopentene), and

2-methylbut-2-ene 2-Methyl-2-butene, 2m2b, 2-methylbut-2-ene, also beta-isoamylene is an alkene hydrocarbon with the molecular formula C5H10. Used as a free radical scavenger in trichloromethane (chloroform) and dichloromethane (methylene chloride). John Snow, t ...

(isoamylene). Isoamylene is one of three main byproducts of

deep catalytic cracking Deep or The Deep may refer to: Places United States * Deep Creek (Appomattox River tributary), Virginia * Deep Creek (Great Salt Lake), Idaho and Utah * Deep Creek (Mahantango Creek tributary), Pennsylvania * Deep Creek (Mojave River tributary ...

(DCC), which is very similar to the operation of the fluid catalytic cracking (FCC). The DCC uses

vacuum gas oil Diesel fuel , also called diesel oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and t ...

(VGO) as a feedstock to produce primarily propylene, isobutylene, and isoamylene. The rise in demand for polypropylene has encouraged the growth of the DCC, which is operated very much like FCC. Isobutylene and isoamylene feedstocks are necessary for the production of the much debated gasoline blending components methyl ''tert''-butyl ether and ''tert''-amyl methyl ether.

Production of fuels

Propylene, isobutene, and amylenes are feedstock in

alkylation unit An alkylation unit (alky) is one of the conversion processes used in petroleum refineries. It is used to convert isobutane and low-molecular-weight alkenes (primarily a mixture of propene and butene) into alkylate, a high octane gasoline componen ...

s of refineries. Using isobutane, blendstocks are generated with high branching for good combustion characteristics. Amylenes are valued as precursors to fuels, especially aviation fuels of relatively low volatility, as required by various regulations.

References

{{Hydrides by group Alkenes