Chemistry · Ch 14 — Haloalkanes and Haloarenes
Nomenclature of Haloarenes
Nomenclature of Haloarenes
IUPAC names a haloarene by prefixing 'halo' (fluoro/chloro/bromo/iodo) to the aromatic hydrocarbon's name, exactly as for a substituted benzene -- e.g. C6H5Cl is chlorobenzene. For a disubstituted ring the 1,2-/1,3-/1,4- relationship is indicated by the ortho/meta/para prefixes respectively -- e.g. 1-chloro-2-nitrobenzene is o-chloronitrobenzene, and 1-bromo-4-chlorobenzene is p-bromochlorobenzene. For a polyhalogenated arene, numbering is chosen to give the lowest possible locants overall, and the individual halogens are cited in alphabetical order -- e.g. 1-bromo-3-chloro-5-iodobenzene. A key distinction to keep straight: the halogen must be bonded DIRECTLY to a ring carbon for the compound to be a haloarene (aryl halide) -- if it instead sits on a side-chain carbon, as in benzyl chloride (C6H5-CH2-Cl), …
| S.No | Compound | IUPAC name |
|---|---|---|
| 1 | 1,2-dichlorobenzene (Cl at C1, C2) | 1,2-Dichlorobenzene |
| 2 | 1,3-dibromobenzene (Br at C1, C3) | 1,3-Dibromobenzene |
| 3 | 1,3,5-tribromobenzene (Br at C1, C3, C5) | 1,3,5-Tribromobenzene |
| 4 | benzene with F, I, Br substituents | 1-Bromo-4-fluoro-2-iodobenzene |