Aromatic Chemistry - Benzene Nomenclature (A-Level Chemistry)

Benzene Nomenclature

Aromatic Compounds

Naming Aromatic Compounds

Compounds which contain a benzene ring are collectively known to as aromatic compounds or arenes.

Arenes can be named in two ways:

  • As substituted benzene rings – For example, chlorobenzne, benzoic acid (or benzene-carboxylic acid), and 1,3-dimethylbenzene
  • As compounds with a phenyl group – For example, phenol or phenylamine. The phenyl group has molecular formula Cā‚†Hā‚….

When a benzene ring has more than one functional groups substituted into it, the name of the resulting arene has to include the number of the C atom each functional group is attached to. When numbering C atoms in the benzene ring the following rules are followed:

  • If all functional groups are the same – Pick any of the functional groups and give number the carbon atom it is attached to as C number 1. Then count around so that you get the lowest possible numbers.
  • If the functional groups are different – Start from the functional group which gives the compound its suffix. Then count around so that you get the lowest possible numbers.

Worked example: Name the following aromatic compounds

Answer:

A. 3-nitro-4-ethyl-phenol

B. 3,5-dichlorophenylamine

C. methyl 3-nitrobenzoate

Still got a question? Leave a comment

Leave a comment

Post as ā€œAnonymousā€