Chapter 16.SE, Problem 29MP

Interpretation Introduction

Interpretation:

Given that sulfonation of aromatic ring with SO₃ and H₂SO₄ is reversible. The product benzenesulfonic acid on heating with H₂SO₄ yields benzene. The mechanism of the desulfonation reaction is to be given and the electrophile involved is to be identified.

Concept introduction:

Sulfonation is a reversible process. Therefore the mechanism of desulfonation is exactly reverse of the sulfonation process.

To propose:

The mechanism for the desulfonation of benzenesulfonic acid to benzene on heating with H₂SO₄. The electrophile involved is to be identified.