cyclohexene

Cyclohexene is an unsaturated hydrocarbon with the chemical formula C6H10. It is a cycloalkene containing a single carbon–carbon double bond within a six-membered ring. The molecule is not aromatic and the double bond endows it with typical alkene reactivity. In its pure form, cyclohexene is a colorless liquid with a sharp odor. It is flammable, immiscible with water, and has a boiling point around 83°C.

Production and preparation methods center on dehydration and dehydrogenation processes. The most common industrial route is the acid-catalyzed dehydration of cyclohexanol. It can also be formed by partial dehydrogenation of cyclohexane under specific catalytic conditions. As a reactive alkene, cyclohexene readily undergoes addition reactions such as hydrogenation to cyclohexane, halogenation, and hydrohalogenation. It can act as a dienophile in Diels–Alder reactions and, by hydration, be converted to cyclohexanol, which can subsequently be oxidized to cyclohexanone.

Applications and significance stem from its role as a versatile synthetic building block. Cyclohexene serves as an important feedstock for preparing cyclohexanol and cyclohexanone, derivatives that are central to the production of adipic acid, a precursor for nylon. It also finds use as a solvent and as a starting material in various laboratory and industrial syntheses.

Safety and storage considerations include its flammability and irritant nature. It should be handled in well-ventilated areas away from heat and oxidizers, with appropriate protective equipment. Storage may require measures to minimize peroxide formation and other instability.