1-Hexene

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1-Hexene

Chemical name	Hex-1-ene
Chemical formula	C₆H₁₂
Molecular mass	84.1608 g/mol
CAS number	[592-41-6]
DOT #:	UN 2370
State at STP	Liquid
Water solubility	insoluble
Density	0.673 g/cm³
Melting point	-139.8 °C
Boiling point	63 °C
Flashpoint	-26 °C
vapor density	3
vapor pressure	2.6 PSIA
Critical temperature	447.40 °F
Critical pressure	458 psi
Critical density	0.241 g/ml
Refractive index	1.3879
SMILES	C=CCCCC
Disclaimer and references

1-hexene is a higher olefin, or alkene, with a formula C₆H₁₂. 1-hexene is an alpha-olefin, meaning that the double bond is located at the alpha (primary) position, endowing this compound with higher reactivity and thus useful chemical properties. 1-hexene is one of industrially important linear alpha olefins.

1 Synthesis
2 Applications
3 Synonyms
4 External links

[edit] Synthesis

Industrially, 1-hexene is commonly manufactured by two main routes: oligomerization of ethene and by Fischer-Tropsch synthesis followed by purification. Another route to 1-hexene which has been used commercially on small scale is dehydration of alcohols. Prior to about 1970's 1-hexene was also manufactured by thermal cracking of waxes, whereas linear internal hexenes were also manufactured by chlorination/dehydrochlorination of linear paraffins.

There are five commercial processes which oligomerize ethene to 1-hexene. Four of these processes produce 1-hexene as a part of a wide distribution of alpha-olefins. Typically, 1-hexene content of the entire distribution of alpha-olefins ranges from about 20% of the distribution in the Ethyl (Innovene) process to about 12% of distribution in some modes of the Gulf (CP Chemicals) and Idemitsu processes.

The only commercial process to isolate 1-hexene from a wide mixture of C₆ hydrocarbons is practised by Sasol Ltd., a South African oil and gas and petrochemical company. Sasol commercially employs Fischer-Tropsch synthesis to make fuels from synthesis gas derived from coal and recovers 1-hexene from these fuel streams, where the initial 1-hexene concentration in a narrow distillation cut may be 60%, with the remainder being vinylidenes, linear and branched internal olefins, linear and branched paraffins, alcohols, aldehydes, carboxylic acids and aromatic compounds.

Synthesis of 1-hexene as a part of multi-product ethene oligomerization process or a Fischer-Tropsch process is covered in an article on Linear alpha olefins.

One process, the Phillips ethene trimerization process, produces only 1-hexene.

[edit] Applications

The primary, even overwhelming, 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, respectively.

Another significant use of 1-hexene is for production of linear aldehyde via OXO Synthesis (hydroformulation) for later production of the short-chain fatty acid heptanoic acid, a carboxylic acid, by oxidation of an intermediate aldehyde or linear alcohols for plasticizer application by hydrogenation of the aldehyde.