Question

Treatment of p-hydroxybenzoic acid with aqueous bromine leads to the evolution of carbon dioxide and the formation of 2,4,6-tribromophenol. Explain.

Answer 1

Answer:

Aromatization leads to evolution of carbon dioxide

Explanation:

In p-hydroxybenzoic acid, -OH and -COOH groups remain in para position.

The directing effect of -OH and -COOH group act synergistically to react with three equivalent of bromine.

In para position of -OH group, -COOH remains attached along with a Br atom in a same carbon atom. During aromatization of benzene group, this -COOH group decomposes to give carbon dioxide.

Reaction scheme has been shown below.