Chapter 24: Phenols

Reaction of Benzene Sulfonic Acid with Hydroxide

Summary

• This is a useful industrial method for the synthesis of phenol.
• Reagents : Usually NaOH, 300-350 ^oC followed by an acidic work-up to neutralise the phenoxide.
• This represents the oldest method for the industrial preparation of phenol.
• The reaction occurs via the addition-elimination mechanism with SO₃^2- functioning as the leaving group.

• Can you remember how to prepare benzene sulfonic acid ?