Chapter 17.2, Problem 17.2P

Interpretation Introduction

Interpretation:

A mechanism for the aluminum chloride-catalysed reaction of benzene with chlorine has to be proposed.

Concept introduction:

One of the most important reactions of aromatic compound is electrophilic aromatic substitution. The pi electron cloud of benzene readily attacks a strong electrophile which results in the formation of a carbocation. This carbocation is resonance stablised. It is known as a sigma complex. This complex is not aromatic due to ${\text{sp}}^{\text{3}}$ hybrid carbon atom. The aromaticity is regained by the loss of proton on the tetrahedral carbon atom.