Halogenation

Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs.

[clarification needed] Many specialized reagents exist for and introducing halogens into diverse substrates, e.g. thionyl chloride.

The regiochemistry of the halogenation of alkanes is largely determined by the relative weakness of the C–H bonds.

[3] The iodoform reaction, which involves degradation of methyl ketones, proceeds by the free radical iodination.

Most organic compounds, saturated or otherwise, burn upon contact with F2, ultimately yielding carbon tetrafluoride.

Unsaturated compounds, especially alkenes and alkynes, add halogens: In oxychlorination, the combination of hydrogen chloride and oxygen serves as the equivalent of chlorine, as illustrated by this route to 1,2-dichloroethane: The addition of halogens to alkenes proceeds via intermediate halonium ions.

Aromatic compounds are subject to electrophilic halogenation: This kind of reaction typically works well for chlorine and bromine.

The carboxylic acid is first converted to its silver salt, which is then oxidized with halogen: Many organometallic compounds react with halogens to give the organic halide: All elements aside from argon, neon, and helium form fluorides by direct reaction with fluorine.

Where chlorination of inorganic compounds is practiced on a relatively large scale is for the production of phosphorus trichloride and disulfur dichloride.