3.4.6 Aromatic Chemistry - Friedel.Crafts acylation reactions
Students should:
|
Friedel-Crafts acylation
Friedel Crafts catalysis involves the use of aluminium chloride to polarise chlorine containing compounds, making them susceptible to electrophilic substitution in aromatic compounds.
Acylation means substitution of an alkyl group attached to a carbonyl group. This is a useful way of introducing a carbon chain with a reactive functional group onto an aromatic ring.
The reaction is as follows:
The aluminium trichloride is electron deficient and behaves as a Lewis acid. It can accept an electron pair from the chlorine atom in other chlorine containing molecules. Aluminium chloride is an example of a Friedel-Crafts catalyst:
