Cyclohexene

Cyclohexene  |  |

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Names
Preferred IUPAC name

Cyclohexene

Other names

Tetrahydrobenzene, 1,2,3,4-Tetrahydrobenzene, Benzenetetrahydride, Cyclohex-1-ene, Hexanaphthylene, UN 2256

Identifiers

CAS Number

* 110-83-8 Y

3D model (JSmol)

* Interactive image

Beilstein Reference

| 906737
ChEBI |

* CHEBI:36404 Y

ChEMBL |

* ChEMBL16396 Y

ChemSpider |

* 7788 Y

ECHA InfoCard | 100.003.462
EC Number |

* 203-807-8

Gmelin Reference

| 1659

PubChem CID

* 8079

RTECS number |

* GW2500000

UNII |

* 12L0P8F7GN Y

CompTox Dashboard (EPA)

* DTXSID9038717

InChI

* InChI=1S/C6H10/c1-2-4-6-5-3-1/h1-2H,3-6H2 Y

Key: HGCIXCUEYOPUTN-UHFFFAOYSA-N Y

* InChI=1/C6H10/c1-2-4-6-5-3-1/h1-2H,3-6H2

Key: HGCIXCUEYOPUTN-UHFFFAOYAQ

SMILES

* C1CCC=CC1

Properties

Chemical formula

| C6H10
Molar mass | 82.143 g/mol
Appearance  | colorless liquid
Odor | sweet
Density | 0.8110 g/cm3
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−1·bar−1

Magnetic susceptibility (χ)

| −57.5·10−6 cm3/mol

Refractive index (nD)

| 1.4465
Hazards
GHS labelling:

Pictograms

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)  |

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)[2]
NIOSH (US health exposure limits):

PEL (Permissible)

| TWA 300 ppm (1015 mg/m3)[1]

REL (Recommended)

| TWA 300 ppm (1015 mg/m3)[1]

IDLH (Immediate danger)

| 2000 ppm[1]
Safety data sheet (SDS)  | External MSDS

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Y verify (what is YN ?)

Infobox references

Chemical compound

Cyclohexene is a hydrocarbon with the formula (CH2)4C2H2. 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.[3]

## Production and uses

[edit]

Cyclohexene is produced by the partial hydrogenation of benzene, a process developed by the Asahi Chemical company.[4] 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.[5]

C6H11OH → C6H10 \+ H2O

## Reactions and uses

[edit]

Benzene is converted to cyclohexylbenzene by acid-catalyzed alkylation with cyclohexene.[6] Cyclohexylbenzene is a precursor to both phenol and cyclohexanone.[7]

Hydration of cyclohexene gives cyclohexanol, which can be dehydrogenated to give cyclohexanone, a precursor to caprolactam.[8]

The oxidative cleavage of cyclohexene gives adipic acid. Hydrogen peroxide is used as the oxidant in the presence of a tungsten catalyst.[9]

1,5-Hexadiene is produced by ethenolysis of cyclohexene. Bromination gives 1,2-dibromocyclohexane.[10]

## Structure

[edit]

Cyclohexene is most stable in a half-chair conformation,[11] 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

[edit]

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

## References

[edit]

1. ^ a b c 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 978-3-527-30673-2.
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

[edit]

* International Chemical Safety Card 1054
* NIOSH Pocket Guide to Chemical Hazards. "#0167". National Institute for Occupational Safety and Health (NIOSH).
* Material Safety Data Sheet for cyclohexene
* Safety MSDS data
* Reaction of Cyclohexene with Bromine and Potassium Permanganate
* Cyclohexene synthesis
* Data sheet at inchem.org

* v
* t
* e

Cycloalkenes

Alkenes|

* Cyclopropene
* Cyclobutene
* Cyclopentene
* Cyclohexene
* Cycloheptene
* Cyclooctene
* Cyclononene
* Cyclodecene

Dienes|

* Cyclobutadiene
* Cyclopentadiene
* Cyclohexadiene
* 1,3-Cyclohexadiene
* 1,4-Cyclohexadiene
* Cycloheptadiene
* 1,3-Cycloheptadiene
* 1,4-Cycloheptadiene
* Cyclooctadiene
* 1,5-Cyclooctadiene

Trienes|

* Benzene
* Cycloheptatriene

Tetraenes|

* Cyclooctatetraene
* Cyclononatetraene

*[CID]: Compound ID
*[EPA]: U.S. Environmental Protection Agency
*[H225]: H225: Highly flammable liquid and vapour
*[H302]: H302: Harmful if swallowed
*[H305]: H305: May be harmful if swallowed and enters airways
*[H311]: H311: Toxic in contact with skin
*[H411]: H411: Toxic to aquatic life with long lasting effects
*[P210]: P210: Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
*[P233]: P233: Keep container tightly closed.
*[P240]: P240: Ground and bond container and receiving equipment.
*[P241]: P241: Use explosion-proof electrical/ventilating/light/.../equipment.
*[P242]: P242: Use only non-sparking tools.
*[P243]: P243: Take precautionary measures to prevent static discharges.
*[P264]: P264: Wash ... thoroughly after handling.
*[P270]: P270: Do not eat, drink or smoke when using this product.
*[P273]: P273: Avoid release to the environment.
*[P280]: P280: Wear protective gloves/protective clothing/eye protection/face protection.
*[P301+P310]: P301+P310: IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician.
*[P301+P312]: P301+P312: IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell.
*[P302+P352]: P302+P352: IF ON SKIN: Wash with soap and water.
*[P303+P361+P353]: P303+P361+P353: IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water [or shower].
*[P312]: P312: Call a POISON CENTER or doctor/physician if you feel unwell.
*[P322]: P322: Specific measures (see ... on this label).
*[P330]: P330: Rinse mouth.
*[P331]: P331: Do NOT induce vomiting.
*[P361]: P361: Remove/Take off immediately all contaminated clothing.
*[P363]: P363: Wash contaminated clothing before reuse.
*[P370+P378]: P370+P378: In case of fire: Use ... to extinguish.
*[P391]: P391: Collect spillage.
*[P403+P235]: P403+P235: Store in a well ventilated place. Keep cool.
*[P405]: P405: Store locked up.
*[P501]: P501: Dispose of contents/container to ...
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