Cyclohexene is a
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
with the formula C
6H
10. This
cycloalkene
A cycloalkene or cycloolefin is a type of alkene hydrocarbon which contains a closed ring of carbon atoms and either one or more double bonds, but has no aromatic character. Some cycloalkenes, such as cyclobutene and cyclopentene, can be used as m ...
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
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organ ...
of
benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...
, a process developed by the
Asahi Chemical company. In the laboratory, it can be prepared by dehydration of
cyclohexanol
Cyclohexanol is the organic compound with the formula HOCH(CH2)5. The molecule is related to cyclohexane by replacement of one hydrogen atom by a hydroxyl group. This compound exists as a deliquescent colorless solid with a camphor-like odor, w ...
.
:
:
Reactions and uses
Benzene is converted to
cyclohexylbenzene by acid-catalyzed alkylation with cyclohexene. Cyclohexylbenzene is a precursor to both phenol and cyclohexanone.
Hydration of cyclohexene gives
cyclohexanol
Cyclohexanol is the organic compound with the formula HOCH(CH2)5. The molecule is related to cyclohexane by replacement of one hydrogen atom by a hydroxyl group. This compound exists as a deliquescent colorless solid with a camphor-like odor, w ...
, which can be
dehydrogenated to give
cyclohexanone, a precursor to
caprolactam
Caprolactam (CPL) is an organic compound with the formula (CH2)5C(O)NH. This colourless solid is a lactam (a cyclic amide) of caproic acid. Global demand for this compound is approximately five million tons per year, and the vast majority is use ...
.
The
oxidative cleavage of cyclohexene gives adipic acid.
Hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%� ...
is used as the oxidant in the presence of a tungsten catalyst. Bromination gives 1,2-dibromocyclohexane.
Structure
Cyclohexene is most stable in a half-chair
conformation,
unlike the preference for a chair form of
cyclohexane. One basis for the
cyclohexane conformation
In organic chemistry, cyclohexane conformations are any of several three-dimensional shapes adopted by molecules of cyclohexane. Because many compounds feature structurally similar six-membered rings, the structure and dynamics of cyclohexane ...
al preference for a chair is that it allows each bond of the ring to adopt a
staggered conformation
In organic chemistry, a staggered conformation is a chemical conformation of an ethane-like moiety abcX–Ydef in which the substituents a, b, and c are at the maximum distance from d, e, and f; this requires the torsion angles to be 60°. It ...
. 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*
ttp://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0183 Cyclohexene synthesisData sheet at inchem.org
References
{{cycloalkenes
Cycloalkenes
Hydrocarbon solvents
Foul-smelling chemicals