how to prpare phenol from aniline
Answers
Phenol are the organic compounds containing benzene ring bonded to a hydroxyl group. They are also known as carbolic acids. They are weak acids and generally form phenoxide ions by losing one positive hydrogen ion (H+) from hydroxyl group. In earlier days, phenol were primarily synthesized from coal tar. Nowadays, with advancements in technologies, certain new methods have come up for the preparation of phenols in laboratories. In laboratories, phenol is primarily synthesized from benzene derivatives. Some of the methods of preparation of phenols are explained below:
Preparation of phenols from haloarenes: Chlorobenzene is an example of haloarenes which is formed by mono substitution of benzene ring. When chlorobenzene is fused with sodium hydroxide at 623K and 320 atm sodium phenoxide is produced. Finally, sodium phenoxide on acidification gives phenols.
Aniline can be converted to phenol by converting it to a diazonium salt and hydrolysing with water.
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When an aniline is treated with nitrous (NaNO2 + HCl) acid at 273 – 278 K, diazonium salts are obtained. These diazonium salts are highly reactive in nature. Upon warming with water, these diazonium salts finally hydrolyse to phenols. Phenols can also be obtained from diazonium salts by treating it with dilute acids.
