Chapter 23, Problem 23.29P

Interpretation Introduction

Interpretation:

It is to be shown how to synthesize benzene-1, 4-dicarboxylic acid from benzene, using ethanol as the only other source of carbon.

Concept introduction:

An aromatic compound undergoes electrophilic substitution reaction with electrophiles. Carbonations act as an electrophile and can be prepared from an alkene or alcohol under acidic conditions and also from an alkyl halide using a strong Lewis acid, ${\text{AlCl}}_{\text{3}}$ as a catalyst. In the first step, an electrophilic addition of the carbocation takes place to the carbon of the aromatic ring. In the second step, electrophilic elimination takes place, in which, the proton is departs from the substrate to form the final product. When benzene is treated with an alkyl halide in the presence of a strong Lewis acid (e.g. ${\text{AlCl}}_{\text{3}}$), as a catalyst, alkylation takes place at the benzene ring known as a Friedel-Crafts alkylation reaction. The complete oxidation of the alkyl group (which onto the aromatic ring) to a carboxylic acid group (${\text{CO}}_{\text{2}}\text{H}$) is done by refluxing it with alkaline ${\text{KMnO}}_{\text{4}}$.