A2 4 39 © RWGrime (Chemsheets.co.uk)
24/10/19
4.6 – NAMING AROMATIC COMPOUNDS
Aromatic compounds are often named as derivatives of benzene, so benzene forms the root of the name. Some aromatic
compounds have old non-systematic names – some of these are shown underneath. However, chemists seem to deviate
and break the rules when it comes to naming aromatic compounds, and at A level the crucial thing is to be able to work out
the structure from the name.
CH3
Cl
methylbenzene
(toluene)
NO2
chlorobenzene
COOH
nitrobenzene
benzenecarboxylic acid
(benzoic acid)
If two or more substituents are present on the benzene ring, their positions must be indicated by the use of numbers. This
should be done to give the lowest possible numbers to the substituents. When two or more different substituents are
present, they are listed in alphabetical order.
COOH
CH3
CH3
COOH
OH
CH3
O2N
NO2
Cl
1,3-dimethylbenzene
(m-xylene)
4-methyl-1-chlorobenzene
2-hydroxybenzenecarboxylic
acid
3,5-dinitrobenzenecarboxylic
acid
The bezene ring can be regarded as a substituent on another molecule, like alkyl groups are. The C 6H5- group is known as
the phenyl group.
NH2
CH
CH2
CH3
CH2
CH2
CH3
O
CH3
C
phenylamine
(aniline)
phenylethene
O
O
O
C
phenylethanone
O
CH3
C
O
2-phenylbutane
NH
C
CH3
CH3
phenyl ethanoate
methyl benzenecarboxylate
(methyl benzoate)
N-phenylethanamide
There are some other compounds to be aware of, such as phenol.
OH
OH
OH
Cl
Cl
OH
OH
NO2
Cl
phenol
2,4,6-trichlorophenol
(TCP)
benzene-1,2-diol
2-nitrophenol