Question

Predict the major products of treating the following compounds with hot, concentrated potassium permanganate, followed by acidification with dilute HCl.

(a) isopropylbenzene

(b) p-xylene

(c) tetralin

Short answer

(a) benzoic acid

(b) terephthalic acid

(c) phthalic acid

Step-by-step solution

Permanganate Oxidation.

Potassium permanganate is a strong oxidizing reagent so it plays a vital role in oxidation.An aromatic ring imparts extra stability to the nearest carbon atom of its side chains. The oxidation induced by KMnO₄ is known as permanganate oxidation.

Functional groups such as -NO₂ , halogens, -COOH, and -SO₃H usually survive this brutal oxidation.

Subpart (a) The major products of the reaction of isopropylbenzene.

On reacting isopropylbenzene with hot, concentrated potassium permanganate, followed by acidification with dilute HCl.

isopropylbenzene ->benzoic acid

Subpart (b) The major products of the reaction of p-xylene.

On reacting p-xylene with hot, concentrated potassium permanganate, followed by acidification with dilute HCl.

p-xylene -> terephthalic acid

Subpart (c) The major products of the reaction of tetralin.

On reacting tetralin with hot, concentrated potassium permanganate, followed by acidification with dilute HCl.

tetralin -> phthalic acid