Why the colour of phenol changes on standing in air?

1 Answer
Ernest Z.
May 5, 2018

Here's what I find.

Explanation:

The #"OH"# group strongly activates the aromatic ring to attack by radicals and electrophilic species.

Thus, the oxygen in air slowly oxidizes the phenol to quinone.

One molecule of quinone bonds strongly to two molecules of phenol to form a brilliant red complex called phenoquinone.

The deepness of the colour depends on the extent of oxidation of the phenol.

i.stack.imgur.com

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