alkenes

Variant: olefines; olefins

Unsaturated hydrocarbons that contain one or more double carbon-carbon bonds in their molecules. In systematic chemical nomenclature alkene names end in the suffix -ene. Alkenes that have only one double bond form a homologous series (the alkene series) starting ethene (ethylene), CH₂:CH₂, propene, CH₃CH:CH₂, etc. The general formula is C_nH_2n. Higher members of the series show isomerism depending on position of the double bond; for example, butene (C₄H₈) has two isomers, which are (1) but-1-ene (C₂H₅CH:CH₂) and (2) but-2-ene (CH₃CH:CHCH₃): see formulae. Alkenes can be made by dehydration of alcohols (passing the vapour over hot pumice):

An alternative method is the removal of a hydrogen atom and halogen atom from a haloalkane by potassium hydroxide in hot alcoholic solution:
Alkenes typically undergo addition reactions to the double bond. They can be tested for by the Baeyer test. See also hydrogenation; oxo process; ozonolysis; Ziegler process.


Alkenes

External Links:

• http://www.acdlabs.com/iupac/nomenclature/79/r79_53.htm -- Information about IUPAC nomenclature

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