Cyclohexene Explained

Cyclohexene is a hydrocarbon with the formula . 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.^[1]

Production and uses

Cyclohexene is produced by the partial hydrogenation of benzene, a process developed by the Asahi Chemical company.^[2] 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.^[3]

Reactions and uses

Benzene is converted to cyclohexylbenzene by acid-catalyzed alkylation with cyclohexene.^[4] Cyclohexylbenzene is a precursor to both phenol and cyclohexanone.^[5]

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.^[6]

1,5-Hexadiene is produced by ethenolysis of cyclohexene. Bromination gives 1,2-dibromocyclohexane.^[7]

Structure

Cyclohexene is most stable in a half-chair conformation,^[8] 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

• Diels-Alder reaction
• Cyclohexa-1,3-diene
• Cyclohexa-1,4-diene

External links

• • • Material Safety Data Sheet for cyclohexene
• Safety MSDS data
• Reaction of Cyclohexene with Bromine and Potassium Permanganate
• Cyclohexene synthesis
• Data sheet at inchem.org

Notes and References

1. 10.1038/s41467-024-46556-6 . Complete separation of benzene-cyclohexene-cyclohexane mixtures via temperature-dependent molecular sieving by a flexible chain-like coordination polymer . 2024 . Xie . Feng . Chen . Lihang . Cedeño Morales . Eder Moisés . Ullah . Saif . Fu . Yiwen . Thonhauser . Timo . Tan . Kui . Bao . Zongbi . Li . Jing . Nature Communications . 15 . 1 . 2240 . 38472202 . 10933443 . 2024NatCo..15.2240X .
2. Cyclohexanol, method for producing cyclohexanol, and method for producing adipic acid. 26 Sep 2017. Narisawa. Tanaka. Naoki. Katsutoshi. US. 9771313.
3. 10.15227/orgsyn.005.0033. Cyclohexene. Organic Syntheses. 1925. 5. 33. G. H. Coleman, H. F. Johnstone.
4. 10.15227/orgsyn.019.0036. Cyclohexylbenzene. Organic Syntheses. 1939. 19. 36. B. B. Corson, V. N. Ipatieff.
5. Web site: What's New in Phenol Production? . Plotkin . Jeffrey S. . American Chemical Society . 2016-03-21 . 2018-01-02 . https://web.archive.org/web/20191027122212/https://www.acs.org/content/acs/en/pressroom/cutting-edge-chemistry/what-s-new-in-phenol-production-.html . 2019-10-27 . dead .
6. Green Chemistry in the Organic Teaching Laboratory: An Environmentally Benign Synthesis of Adipic Acid . Scott M. . Reed . James E. . Hutchison . J. Chem. Educ. . 2000 . 77 . 12 . 1627–1629 . 10.1021/ed077p1627. 2000JChEd..77.1627R .
7. 10.15227/orgsyn.012.0026. 1,2-Dibromocyclohexane. Organic Syntheses. 1932. 12. 26. H. R. Snyder, L. A. Brooks.
8. Conformational preferences and interconversion barriers in cyclohexene and derivatives . Frederick R. . Jensen . C. Hackett . Bushweller . J. Am. Chem. Soc. . 1969 . 91 . 21 . 5774–5782 . 10.1021/ja01049a013.