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
PubChemCID	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	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)	-57.5·10−6cm3/mol
Refractive index(nD)	1.4465
Hazards
	GHSlabelling:
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)	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 doseor 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/m3)
REL(Recommended)	TWA 300 ppm (1015 mg/m3)
IDLH(Immediate danger)	2000 ppm
Safety data sheet(SDS)	External MSDS
	Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa). verify(what is?) Infobox references

Cyclohexeneis ahydrocarbonwith the formula(CH₂)₄C₂H₂.It is an example of acycloalkene.At room temperature, cyclohexene is a colorlessliquidwith a sharp odor. Among its uses, it is anintermediatein the commercial synthesis ofnylon.^[3]

Production and uses

Cyclohexene is produced by the partialhydrogenationofbenzene,a process developed by theAsahi Chemicalcompany.^[4]The main product of the process is cyclohexane because cyclohexene is more easily hydrogenated than benzene.

In the laboratory, it can be prepared bydehydrationofcyclohexanol.^[5]

C₆H₁₁OH → C₆H₁₀+ H₂O

Reactions and uses

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

Hydration of cyclohexene givescyclohexanol,which can bedehydrogenatedto givecyclohexanone,a precursor tocaprolactam.^[8]

Theoxidative cleavageof cyclohexene givesadipic acid.Hydrogen peroxideis used as the oxidant in the presence of a tungsten catalyst.^[9]

1,5-Hexadieneis produced byethenolysisof cyclohexene. Bromination gives 1,2-dibromocyclohexane.^[10]

Structure

Cyclohexene is most stable in a half-chairconformation,^[11]unlike the preference for a chair form ofcyclohexane.One basis for thecyclohexane conformationalpreference for a chair is that it allows each bond of the ring to adopt astaggered conformation.For cyclohexene, however, the alkene is planar, equivalent to an eclipsed conformation at that bond.

References

^^a ^b ^cNIOSH Pocket Guide to Chemical Hazards."#0167".National Institute for Occupational Safety and Health(NIOSH).
^"Cyclohexene".Immediately Dangerous to Life or Health Concentrations (IDLH).National Institute for Occupational Safety and Health(NIOSH).
^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.PMC10933443.PMID 38472202.
^US 9771313,Narisawa, Naoki & Tanaka, Katsutoshi, "Cyclohexanol, method for producing cyclohexanol, and method for producing adipic acid", published 26 Sep 2017
^G. H. Coleman, H. F. Johnstone (1925). "Cyclohexene".Organic Syntheses.5:33.doi:10.15227/orgsyn.005.0033.
^B. B. Corson, V. N. Ipatieff (1939). "Cyclohexylbenzene".Organic Syntheses.19:36.doi:10.15227/orgsyn.019.0036.
^Plotkin, Jeffrey S. (2016-03-21)."What's New in Phenol Production?".American Chemical Society. Archived fromthe originalon 2019-10-27.Retrieved2018-01-02.
^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.
^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.
^H. R. Snyder, L. A. Brooks (1932). "1,2-Dibromocyclohexane".Organic Syntheses.12:26.doi:10.15227/orgsyn.012.0026.
^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

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

[PGCH-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.PMC10933443.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.

[acs_phenol-7] Plotkin, Jeffrey S. (2016-03-21)."What's New in Phenol Production?".American Chemical Society. Archived fromthe originalon 2019-10-27.Retrieved2018-01-02.

[Ullmann-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.

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