1. Introduction: Aromatic
Chemistry

2. Arenes
• Arenes: aromatic hydrocarbons containing one
or more benzene ring.
• A benzene ring is a ring of 6 carbon molecules,
each bonded with one hydrogen molecule
with the formula C6H6.
• Represented like this:

3. Naming Benzene Compounds
• When a hydrogen on the benzene ring is
replaced by a molecule or group it takes the
form “(group)benzene”

4. Eg: C6H5Cl = “Chlorobenzene”
Common groups include:
-Cl (Chloro)
-Br (Bromo)
-I (Iodo)
-NO2 (Nitro)
-CH3 (Methyl)

5. Numbering Groups
• With 2 or more groups, the name must show
their positions on the ring.
• Smallest possible numbers are used.
• Groups are listed in alphabetical order. (Eg:
bromomethyl, not methylbromo).

6. Numbering based on methylbenzene at
position 1:

7. Benzene
• Used to synthesize many aromatic compounds
and materials.
• Derivatives used to make detergents,
explosives, dies.
• Component of crude oil, cigarette smoke and
petrol.

8. Properties of Benzene
• Colourless liquid, sweet smell, highly
flammable.
• Formed naturally (volcanoes + forest fires) and
artificially.