Cyclohexene: Structure, Properties, and Uses

Structure and properties

The ring backbone is a six-membered arrangement with one carbon–carbon double bond; this gives a combination of sp2 and sp3 hybridized carbon atoms and affects bond angles and reactivity. The double bond is the site of typical alkene chemistry (addition reactions and oxidation). Spectroscopic methods such as infrared and nuclear magnetic resonance readily detect the olefinic group and help distinguish cyclohexene from saturated or acyclic hydrocarbons.

Conformation and stereochemistry

Unlike fully saturated cyclohexane, cyclohexene cannot adopt a single perfect chair conformation because the double bond imposes planarity on two adjacent carbons. The ring adopts a distorted geometry to accommodate the sp2 centers; this influences how substituents are presented and how additions across the double bond proceed. Because the double bond is locked into the ring, cyclohexene does not display E/Z stereoisomerism in the same way linear alkenes do.

Production and applications

Cyclohexene is produced and used mainly as an intermediate in organic synthesis. It can arise in partial hydrogenation or dehydrogenation processes and serves as a precursor to cyclohexanol, cyclohexanone and other derivatives that are important in the manufacture of polymers, coatings and fine chemicals. In the laboratory it is a common substrate for hydrogenation, halogenation, epoxidation and hydroboration–oxidation reactions.

Safety and handling

Cyclohexene is flammable and can be irritating to the skin and respiratory tract; industrial and laboratory use requires adequate ventilation, grounding of containers and avoidance of ignition sources. It should be handled using appropriate personal protective equipment and stored in a cool, well-ventilated area away from oxidizers.

Related topics and further reading

• six-membered ring
• hydrocarbon
• carbon atoms
• atoms and bonding
• hydrogen atoms
• solvents and miscibility