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Cyclohexene

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Cyclohexene
Names
Preferred IUPAC name Cyclohexene
Other names Tetrahydrobenzene, 1,2,3,4-Tetrahydrobenzene, Benzenetetrahydride, Cyclohex-1-ene, Hexanaphthylene, UN 2256
Identifiers
CAS Number
3D model (JSmol)
Beilstein Reference 906737
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.462 Edit this at Wikidata
EC Number
  • 203-807-8
Gmelin Reference 1659
PubChem CID
RTECS number
  • GW2500000
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C6H10/c1-2-4-6-5-3-1/h1-2H,3-6H2Key: HGCIXCUEYOPUTN-UHFFFAOYSA-N
  • InChI=1/C6H10/c1-2-4-6-5-3-1/h1-2H,3-6H2Key: HGCIXCUEYOPUTN-UHFFFAOYAQ
SMILES
  • C1CCC=CC1
Properties
Chemical formula C6H10
Molar mass 82.143 g/mol
Appearance colorless liquid
Odor sweet
Density 0.8110 g/cm
Melting point −103.5 °C (−154.3 °F; 169.7 K)
Boiling point 82.98 °C (181.36 °F; 356.13 K)
Solubility in water slightly soluble in water
Solubility miscible with organic solvents
Vapor pressure 8.93 kPa (20 °C)

11.9 kPa (25 °C)

Henry's law
constant (kH) 		0.022 mol·kg·bar
Magnetic susceptibility (χ) -57.5·10 cm/mol
Refractive index (nD) 1.4465
Hazards
GHS labelling:
Pictograms GHS02: FlammableGHS06: ToxicGHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Signal word Danger
Hazard statements H225, H302, H305, H311, H411
Precautionary statements P210, P233, P240, P241, P242, P243, P264, P270, P273, P280, P301+P310, P301+P312, P302+P352, P303+P361+P353, P312, P322, P330, P331, P361, P363, P370+P378, P391, P403+P235, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1 3 0
Flash point −12 °C (10 °F; 261 K)
Autoignition
temperature 		244 °C (471 °F; 517 K)
Explosive limits 0.8–5 %
Lethal dose or concentration (LD, LC):
LD50 (median dose) 1407 mg/kg (oral, rat)
LCLo (lowest published) 13,196 ppm (mouse, 2 hr)
NIOSH (US health exposure limits):
PEL (Permissible) TWA 300 ppm (1015 mg/m)
REL (Recommended) TWA 300 ppm (1015 mg/m)
IDLH (Immediate danger) 2000 ppm
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). checkY verify (what is  ?) Infobox references
Chemical compound

Cyclohexene is a hydrocarbon with the formula (CH2)4C2H2. It is an example of a cycloalkene. At room temperature, cyclohexene is a colorless liquid with a sharp odor. Among its uses, it is an intermediate in the commercial synthesis of nylon.

Production and uses

Cyclohexene is produced by the partial hydrogenation of benzene, a process developed by the Asahi Chemical company. The main product of the process is cyclohexane because cyclohexene is more easily hydrogenated than benzene.

In the laboratory, it can be prepared by dehydration of cyclohexanol.

C6H11OH → C6H10 + H2O

Reactions and uses

Benzene is converted to cyclohexylbenzene by acid-catalyzed alkylation with cyclohexene. Cyclohexylbenzene is a precursor to both phenol and cyclohexanone.

Hydration of cyclohexene gives cyclohexanol, which can be dehydrogenated to give cyclohexanone, a precursor to caprolactam.

The oxidative cleavage of cyclohexene gives adipic acid. Hydrogen peroxide is used as the oxidant in the presence of a tungsten catalyst.

1,5-Hexadiene is produced by ethenolysis of cyclohexene. Bromination gives 1,2-dibromocyclohexane.

Structure

Cyclohexene is most stable in a half-chair conformation, unlike the preference for a chair form of cyclohexane. One basis for the cyclohexane conformational preference for a chair is that it allows each bond of the ring to adopt a staggered conformation. For cyclohexene, however, the alkene is planar, equivalent to an eclipsed conformation at that bond.

See also

References

  1. ^ NIOSH Pocket Guide to Chemical Hazards. "#0167". National Institute for Occupational Safety and Health (NIOSH).
  2. "Cyclohexene". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. Xie, Feng; Chen, Lihang; Cedeño Morales, Eder Moisés; Ullah, Saif; Fu, Yiwen; Thonhauser, Timo; Tan, Kui; Bao, Zongbi; Li, Jing (2024). "Complete separation of benzene-cyclohexene-cyclohexane mixtures via temperature-dependent molecular sieving by a flexible chain-like coordination polymer". Nature Communications. 15 (1): 2240. Bibcode:2024NatCo..15.2240X. doi:10.1038/s41467-024-46556-6. PMC 10933443. PMID 38472202.
  4. US 9771313, Narisawa, Naoki & Tanaka, Katsutoshi, "Cyclohexanol, method for producing cyclohexanol, and method for producing adipic acid", published 26 Sep 2017 
  5. G. H. Coleman, H. F. Johnstone (1925). "Cyclohexene". Organic Syntheses. 5: 33. doi:10.15227/orgsyn.005.0033.
  6. B. B. Corson, V. N. Ipatieff (1939). "Cyclohexylbenzene". Organic Syntheses. 19: 36. doi:10.15227/orgsyn.019.0036.
  7. Plotkin, Jeffrey S. (2016-03-21). "What's New in Phenol Production?". American Chemical Society. Archived from the original on 2019-10-27. Retrieved 2018-01-02.
  8. Musser, Michael T. (2005). "Cyclohexanol and Cyclohexanone". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_217. ISBN 978-3527306732.
  9. Reed, Scott M.; Hutchison, James E. (2000). "Green Chemistry in the Organic Teaching Laboratory: An Environmentally Benign Synthesis of Adipic Acid". J. Chem. Educ. 77 (12): 1627–1629. Bibcode:2000JChEd..77.1627R. doi:10.1021/ed077p1627.
  10. H. R. Snyder, L. A. Brooks (1932). "1,2-Dibromocyclohexane". Organic Syntheses. 12: 26. doi:10.15227/orgsyn.012.0026.
  11. Jensen, Frederick R.; Bushweller, C. Hackett (1969). "Conformational preferences and interconversion barriers in cyclohexene and derivatives". J. Am. Chem. Soc. 91 (21): 5774–5782. doi:10.1021/ja01049a013.

External links

Cycloalkenes
Alkenes
Dienes
Trienes
Tetraenes
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