Cyclohexene

Cyclohexene
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 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	906737
ChEBI	CHEBI:36404 ;
ChEMBL	ChEMBL16396 ;
ChemSpider	7788 ;
ECHA InfoCard	100.003.462
EC Number	203-807-8;
Gmelin Reference	1659
PubChem CID	8079;
RTECS number	GW2500000;
UNII	12L0P8F7GN ;
CompTox Dashboard (EPA)	DTXSID9038717 ;
	InChI InChI=1S/C6H10/c1-2-4-6-5-3-1/h1-2H,3-6H2 Key: HGCIXCUEYOPUTN-UHFFFAOYSA-N ; 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	insoluble 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
Safety data sheet	External MSDS
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H225, H302, H304, H311, H411
GHS precautionary statements	P210, P233, P240, P241, P242, P243, P264, P270, P273, P280, P301+310, P301+312, P302+352, P303+361+353, P312, P322, P330, P331, P361, P363, P370+378, P391, P403+235, P405, P501
NFPA 704 (fire diamond)	3 1 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)	1946 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/m3)
REL (Recommended)	TWA 300 ppm (1015 mg/m3)
IDLH (Immediate danger)	2000 ppm
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Cyclohexene is a hydrocarbon with the formula C₆H₁₀. This cycloalkene is a colorless liquid with a sharp smell. It is an intermediate in various industrial processes. Cyclohexene is not very stable upon long term storage with exposure to light and air because it forms peroxides.

Production and uses

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

Reactions and uses

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

Hydration of cyclohexene gives cyclohexanol, which can be dehydrogenated to give cyclohexanone, a precursor to caprolactam.^[5]

The oxidative cleavage of cyclohexene gives adipic acid. Hydrogen peroxide is used as the oxidant, in the presence of a tungsten catalyst.^[6]

Cyclohexene is also a precursor to maleic acid, dicyclohexyladipate, and cyclohexene oxide. Furthermore, it is used as a solvent.

Structure

Cyclohexene is most stable in a half-chair conformation,^[7] 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.

External links

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

References

^ ^a ^b ^c NIOSH Pocket Guide to Chemical Hazards. "#0167". National Institute for Occupational Safety and Health (NIOSH).
^ "Cyclohexene". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ [1], Narisawa, Naoki & Katsutoshi Tanaka, "Cyclohexanol, method for producing cyclohexanol, and method for producing adipic acid"
^ 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.
^ Musser, Michael T. (2005). "Cyclohexanol and Cyclohexanone". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_217.
^ 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.
^ 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.

[PGCH-1] NIOSH Pocket Guide to Chemical Hazards. "#0167". National Institute for Occupational Safety and Health (NIOSH).

[2] "Cyclohexene". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[3] [1], Narisawa, Naoki & Katsutoshi Tanaka, "Cyclohexanol, method for producing cyclohexanol, and method for producing adipic acid"

[acs_phenol-4] 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.

[Ullmann-5] Musser, Michael T. (2005). "Cyclohexanol and Cyclohexanone". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_217.

[6] 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.

[7] 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.

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