Friedel-Crafts acylation
Benzene reacts with an acyl chloride or anhydride in the presence of anhydrous AlCl3 to give an aromatic ketone.
BenzeneC₆H₆Arene - Step 1
CH₃COCl, anhydrous AlCl₃
AcetophenoneC₆H₅COCH₃Ketone
How it works
- AlCl₃ removes Cl⁻ from RCOCl to give the acylium ion RCO⁺.
- The acylium ion attacks the ring.
- Loss of H⁺ gives the ketone and regenerates AlCl₃.
What it makes
Acetophenone and benzophenone.
Where it fails
The product ketone is deactivated, so it stops at one acyl group. It fails on strongly deactivated rings. Formyl chloride is unstable, so benzaldehyde needs Gattermann-Koch.
Class 12, Chapter 8 Aldehydes, Ketones and Carboxylic Acids
Friedel-Crafts acylation: quick answers
What is formed from benzene and CH3COCl with AlCl3?
Acetophenone (1-phenylethanone).
Why does acylation not give polysubstitution?
The C=O group deactivates the ring.
How do you turn acetophenone into ethylbenzene?
Reduce it by the Clemmensen or Wolff-Kishner reduction.