1-Hexene
Encyclopedia
1-Hexene is an organic compound
with the formula CH2CHC4H9. It is an alkene
that is classified in industry as higher olefin and an alpha-olefin
, the latter term meaning that the double bond is located at the alpha (primary) position, endowing the compound with higher reactivity and thus useful chemical properties. 1-Hexene is an industrially significant linear alpha olefin
. 1-Hexene is a colourless liquid.
and (ii) on-purpose technology. A minor route to 1-hexene, used commercially on smaller scales, is the dehydration of hexanol. Prior to the 1970s, 1-hexene was also manufactured by the thermal cracking of waxes. Linear internal hexenes were manufactured by chlorination
/dehydrochlorination of linear paraffins.
"Ethylene oligomerization" combines ethylene molecules to produce linear alpha-olefins of various chain lengths with an even number of carbon atoms. This approach result in a distribution or “full range” of alpha-olefins. The Shell higher olefin process
(SHOP) employs this approach. Linde and SABIC
have developed the α-SABLIN technology using the oligomerization of ethylene to produce 21 percent 1-hexene. CP Chemicals and Innovene also have full-range processes. Typically, 1-hexene content ranges from about twenty percent distribution in the Ethyl (Innovene) process, whereas only twelve percent of distribution in the CP Chemicals and Idemitsu processes.
An on-purpose route to 1-hexene using ethylene trimerization was first brought on stream in Qatar in 2003 by Chevron-Phillips. A second plant was scheduled to start in 2011 in Saudi Arabia and a third planned for 2014 in the US. The Sasol
process is also considered an on-purpose route to 1-hexene. Sasol commercially employs Fischer-Tropsch synthesis to make fuels from synthesis gas derived from coal. The synthesis recovers 1-hexene from the aforementioned fuel streams, where the initial 1-hexene concentration cut may be 60% in a narrow distillation, with the remainder being vinylidenes, linear and branched internal olefins, linear and branched paraffins, alcohols, aldehydes, carboxylic acids, and aromatic compounds. The trimerization of ethylene by homogeneous catalysts has been demonstrated.
Lummus Technology has recently developed a new on purpose route where 1-butene
reacts with itself (“autometathesis” or “self-disproportionation”) to produce 1-hexene. A semi-commercial unit has been in operation in Tianjin, China to demonstrate the Lummus technology.
Another significant use of 1-hexene is the production of the linear aldehyde heptanal
via hydroformylation
(oxo synthesis). Heptanal can be converted to the short-chain fatty acid
heptanoic acid
or the alcohol heptanol.
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula CH2CHC4H9. It is an alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
that is classified in industry as higher olefin and an alpha-olefin
Alpha-olefin
Alpha-olefins are a family of organic compounds which are olefins or alkenes with a chemical formula CxH2x, distinguished by having a double bond at the primary or alpha position...
, the latter term meaning that the double bond is located at the alpha (primary) position, endowing the compound with higher reactivity and thus useful chemical properties. 1-Hexene is an industrially significant linear alpha olefin
Linear alpha olefin
Linear Alpha Olefins or Normal Alpha Olefins are olefins or alkenes with a chemical formula CxH2x, distinguished from other mono-olefins with a similar molecular formula by linearity of the hydrocarbon chain and the position of the double bond at the primary or alpha position.Linear alpha olefins...
. 1-Hexene is a colourless liquid.
Production
1-Hexene is commonly manufactured by two general routes: (i) full-range processes via the oligomerization of ethyleneEthylene
Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...
and (ii) on-purpose technology. A minor route to 1-hexene, used commercially on smaller scales, is the dehydration of hexanol. Prior to the 1970s, 1-hexene was also manufactured by the thermal cracking of waxes. Linear internal hexenes were manufactured by chlorination
Chlorination
Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water...
/dehydrochlorination of linear paraffins.
"Ethylene oligomerization" combines ethylene molecules to produce linear alpha-olefins of various chain lengths with an even number of carbon atoms. This approach result in a distribution or “full range” of alpha-olefins. The Shell higher olefin process
Shell higher olefin process
The Shell higher olefin process is a chemical process for the production of linear alpha olefins via ethylene oligomerization and olefin metathesis invented and exploited by Royal Dutch Shell. The olefin products are converted to fatty aldehydes and then to fatty alcohols, which are precursors...
(SHOP) employs this approach. Linde and SABIC
SABIC
SABIC is a diversified manufacturing company, active in chemicals and intermediates, industrial polymers, fertilizers and metals. It is the largest public company in Saudi Arabia as listed in Tadawul, but the Saudi government still owns 70% of its shares...
have developed the α-SABLIN technology using the oligomerization of ethylene to produce 21 percent 1-hexene. CP Chemicals and Innovene also have full-range processes. Typically, 1-hexene content ranges from about twenty percent distribution in the Ethyl (Innovene) process, whereas only twelve percent of distribution in the CP Chemicals and Idemitsu processes.
An on-purpose route to 1-hexene using ethylene trimerization was first brought on stream in Qatar in 2003 by Chevron-Phillips. A second plant was scheduled to start in 2011 in Saudi Arabia and a third planned for 2014 in the US. The Sasol
Sasol
Sasol Ltd. is a South African company involved in mining, energy, chemicals and synfuels. In particular, they produce petrol and diesel profitably from coal and natural gas using Fischer-Tropsch process...
process is also considered an on-purpose route to 1-hexene. Sasol commercially employs Fischer-Tropsch synthesis to make fuels from synthesis gas derived from coal. The synthesis recovers 1-hexene from the aforementioned fuel streams, where the initial 1-hexene concentration cut may be 60% in a narrow distillation, with the remainder being vinylidenes, linear and branched internal olefins, linear and branched paraffins, alcohols, aldehydes, carboxylic acids, and aromatic compounds. The trimerization of ethylene by homogeneous catalysts has been demonstrated.
Lummus Technology has recently developed a new on purpose route where 1-butene
1-Butene
1-Butene is an organic chemical compound, linear alpha-olefin , and one of the isomers of butene. The formula is .-Stability:1-Butene is stable in itself but polymerizes exothermically. It is highly flammable and readily forms explosive mixtures with air...
reacts with itself (“autometathesis” or “self-disproportionation”) to produce 1-hexene. A semi-commercial unit has been in operation in Tianjin, China to demonstrate the Lummus technology.
Applications
The primary use of 1-hexene is as a comonomer in production of polyethene. High-density polyethene (HDPE) and linear low-density polyethene (LLDPE) use approximately 2–4% and 8–10% of comonomers, respectfully.Another significant use of 1-hexene is the production of the linear aldehyde heptanal
Heptanal
Heptanal or heptanaldehyde is an alkyl aldehyde with a strong fruity odor which is used as an ingredient in cosmetics, perfumes, and flavors. It can be obtained from castor oil by distillation under reduced pressure. Industrially, it is used in the manufacture of 1-heptanol and ethyl heptanoate....
via hydroformylation
Hydroformylation
Hydroformylation, also known as oxo synthesis or oxo process, is an important industrial process for the production of aldehydes from alkenes. This chemical reaction entails the addition of a formyl group and a hydrogen atom to a carbon-carbon double bond...
(oxo synthesis). Heptanal can be converted to the short-chain fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
heptanoic acid
Heptanoic acid
Heptanoic acid, also called enanthic acid, is an organic compound composed of a seven-carbon chain terminating in a carboxylic acid. It is an oily liquid with an unpleasant, rancid odor. It contributes to the odor of some rancid oils...
or the alcohol heptanol.