1-Octene is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

with a formula CH₂CHC₆H₁₃. The

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, an ...

is classified as a higher olefin and

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 ...

, meaning that the

double bond In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betwee ...

is located at the alpha (primary) position, endowing this compound with higher reactivity and thus useful chemical properties. 1-Octene is one of the important

linear alpha olefin Linear alpha olefins (LAO) or normal alpha olefins (NAO) are olefins or alkenes with a chemical formula Cx H2x, distinguished from other mono-olefins with a similar molecular formula by linearity of the hydrocarbon chain and the position of the d ...

s in industry. It is a colourless liquid.

Synthesis

In industry, 1-octene is commonly manufactured by two main routes:

oligomerization In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomers.Quote: ''Oligomer molecule: A molecule of intermediate relativ ...

of ethylene and by Fischer–Tropsch synthesis followed by purification. Another route to 1-octene that has been used commercially on a small scale is

dehydration In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...

of alcohols. Prior to the 1970s, 1-octene was also manufactured by thermal cracking of

wax Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to giv ...

es, whereas linear internal

octene Octene is an alkene with the formula . Several isomers of octene are known, depending on the position and the geometry of the double bond in the carbon chain. The simplest isomer is 1-octene, an alpha-olefin used primarily as a co-monomer in p ...

s were also manufactured by

chlorination Chlorination may refer to: * Chlorination reaction In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transform ...

dehydrochlorination In chemistry, dehydrohalogenation is an elimination reaction which removes a hydrogen halide from a substrate. The reaction is usually associated with the synthesis of alkenes, but it has wider applications. Dehydrohalogenation from alkyl halid ...

linear alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in whic ...

s. There are five commercial processes that

oligomerize In chemistry and biochemistry, an oligomer () is a molecule that consists of a few repeating units which could be derived, actually or conceptually, from smaller molecules, monomer, monomers.Quote: ''Oligomer molecule: A molecule of intermediate ...

ethylene to 1-octene. Four of these processes produce 1-octene as a part of a wide distribution of alpha-olefins. In typical circumstances, 1-hexene content of the entire distribution of alpha-olefins ranges from about 25% of the distribution in the Ethyl ( Innovene) process to about 8% of distribution in some modes of the

Gulf A gulf is a large inlet from the ocean into the landmass, typically with a narrower opening than a bay, but that is not observable in all geographic areas so named. The term gulf was traditionally used for large highly-indented navigable bodies ...

(CP Chemicals) and

Idemitsu is a Japanese petroleum company. It owns and operates oil platforms, refineries, produces and sells petroleum, oils and petrochemical products, and also operates gas stations under the brand and (until 2023) in its own ''Idemitsu'' and ''Shell ...

processes. The only commercial process to isolate 1-octene from a wide mixture of C₈ hydrocarbons is practiced by

Sasol Sasol Limited is an integrated energy and chemical company based in Sandton, South Africa. The company was formed in 1950 in Sasolburg, South Africa and built on processes that were first developed by German chemists and engineers in the early ...

, a

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

n oil and gas and petrochemical company. For commercial purposes, Sasol employs Fischer–Tropsch synthesis to make fuels from

synthesis gas Syngas, or synthesis gas, is a mixture of hydrogen and carbon monoxide, in various ratios. The gas often contains some carbon dioxide and methane. It is principly used for producing ammonia or methanol. Syngas is combustible and can be used ...

derived from coal and recovers 1-octene from these fuel streams, where the initial 1-octene concentration in a narrow

distillation Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heat ...

cut may be 60%, with the remainder being vinylidenes, linear and branched internal olefins, linear and branched paraffins, alcohols,

aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...

s, carboxylic acids, and

aromatic hydrocarbon Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past groupin ...

s. In recent years, two on-purpose 1-octene technologies have been commercialised: a butadiene

telomerization Telomerization is a reaction that produces a particular kind of oligomer with two distinct end groups. The oligomer is called a telomer. Some telomerizations proceed by radical pathways, many do not. A generic equation is: : A-B + n M -> A-M_ ...

plant (Dow, Tarragona), and a 1-heptene to 1-octene plant based on a Fischer-Tropsch-derived C₇ olefin stream (Sasol, Secunda). Sasol is currently in the engineering phase of a new 1-octene technology based on selective tetramerisation of ethylene.

Applications

The main use of 1-octene is as a

comonomer In polymer chemistry, a comonomer refers to a polymerizable precursor to a copolymer aside from the principal monomer. In some cases, only small amounts of a comonomer are employed, in other cases substantial amounts of comonomers are used. Furthe ...

in production of polyethylene.

High-density polyethylene High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a thermoplastic polymer produced from the monomer ethylene. It is sometimes called "alkathene" or "polythene" when used for HDPE pipes. With a high strength-to-density ratio, ...

(HDPE) and

linear low-density polyethylene Linear low-density polyethylene (LLDPE) is a substantially linear polymer (polyethylene), with significant numbers of short branches, commonly made by copolymerization of ethylene with longer-chain olefins. Linear low-density polyethylene differs ...

(LLDPE) use approximately 2–4% and 8–10% of comonomers, respectively. Another significant use of 1-octene is for production of linear

via oxo synthesis (

hydroformylation Hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes from alkenes. This chemical reaction entails the net addition of a formyl group (CHO) and a hydrogen atom to a carbon-carbon d ...

) to give the C9 aldehyde (

nonanal Nonanal, also called nonanaldehyde, pelargonaldehyde or Aldehyde C-9, is an aldehyde. A colourless, oily liquid, nonanal is a component of perfumes. Although it occurs in several natural oils, it is produced commercially by hydroformylation of 1- ...

). Oxidation of this aldehyde gives the short-chain

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, ...

nonanoic acid. Hydrogenation of the same aldehyde gives the fatty alcohol

1-nonanol 1-Nonanol is a straight chain fatty alcohol with nine carbon atoms and the molecular formula CH3(CH2)8OH. It is a colorless oily liquid with a citrus odor similar to citronella oil. Nonanol occurs naturally in orange oil. The primary use of no ...

, which is used as a

plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...

References

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