Chemistry:Cyclohexene

From HandWiki

Cyclohexene is a hydrocarbon with the formula (CH
2
)
4
C
2
H
2
. It is 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]

C
6
H
11
OH → C
6
H
10
+ H
2
O

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.[6]

The oxidative cleavage of cyclohexene gives adipic acid. Hydrogen peroxide is used as the oxidant in the presence of a tungsten catalyst.[7]

1,5-Octadiene is produced by ethenolysis of cyclohexene.[8] Bromination gives 1,2-dibromocyclohexane.[9]

Structure

Cyclohexene is most stable in a half-chair conformation,[10] 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. Xie, Feng; Chen, Lihang; Cedeño Morales, Eder Moisés; Ullah, Saif; Fu, Yiwen; Thonhauser, Timo; Tan, Kui; Bao, Zongbi et al. (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. doi:10.1038/s41467-024-46556-6. PMID 38472202. Bibcode2024NatCo..15.2240X. 
  2. Narisawa, Naoki & Katsutoshi Tanaka, "Cyclohexanol, method for producing cyclohexanol, and method for producing adipic acid", US patent 9771313, published 26 Sep 2017
  3. G. H. Coleman, H. F. Johnstone (1925). "Cyclohexene". Organic Syntheses 5: 33. doi:10.15227/orgsyn.005.0033. 
  4. B. B. Corson, V. N. Ipatieff (1939). "Cyclohexylbenzene". Organic Syntheses 19: 36. doi:10.15227/orgsyn.019.0036. 
  5. Plotkin, Jeffrey S. (2016-03-21). "What's New in Phenol Production?". American Chemical Society. https://www.acs.org/content/acs/en/pressroom/cutting-edge-chemistry/what-s-new-in-phenol-production-.html. 
  6. Musser, Michael T. (2005). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_217. 
  7. 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. doi:10.1021/ed077p1627. Bibcode2000JChEd..77.1627R. 
  8. Kustov, L. M.; Furman, D. B. (2018-07-15). "Catalytic synthesis of octadiene-1,7 from ethylene and cyclohexene". Journal of Organometallic Chemistry. Special Issue dedicated to Prof. Irina Beletskaya 867: 261–265. doi:10.1016/j.jorganchem.2018.01.059. ISSN 0022-328X. https://www.sciencedirect.com/science/article/pii/S0022328X18300779. 
  9. H. R. Snyder, L. A. Brooks (1932). "1,2-Dibromocyclohexane". Organic Syntheses 12: 26. doi:10.15227/orgsyn.012.0026. 
  10. 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.