17.0 Friedel Craft's acylation

  Alkyl Halides and Aryl Halides

The reaction between chlorobenzene with acetyl chloride in the presence of anhydrous aluminum chloride produces $4$-chloroacetophenone as the major product and $2$-chloroacetophenone as the minor product.

Mechanism:

Step 1: Generation of acylium ion (electrophile)

Step 2: Attack of acylium ion at ortho- and para- positions

Step 3: Loss of proton and regeneration of catalysts