Halogenation

Halogenation is a chemical reaction that replaces a hydrogen atom with a halogen atom. More specific descriptions exist that specify the type of halogen: fluorination, chlorination, bromination, and iodination.

In a Markovnikov addition reaction, a halogen like bromine is reacted with an alkene which causes the π-bond to break forming an haloalkane. This makes the hydrocarbon more reactive and bromine as it turns out, is a good leaving group in further chemical reactions such as nucleophilic aliphatic substitution reactions and elimination reactions

Several types of halogenation exist, including:
* free radical halogenation
* ketone halogenation
* Electrophilic halogenation
* Halogen addition reaction

An example of halogenation can be found in the organic synthesis of the anesthetic halothane from trichloroethylene which involves a high temperature bromination in the second step :

Halothane synthesis

See also

*Halogenoalkanes (Alkyl halides)
*Halogenoarenes (Aryl halides)
*Haloketones
*Electrophilic substitution

References

# Synthesis of essential drugs, Ruben Vardanyan, Victor Hruby; Elsevier 2005 ISBN 0444521666