Substitution of the phenolic Hydroxyl Hydrogen

As with the alcohols, the phenolic hydroxyl hydrogen is rather easily replaced by other substituents. For example, phenol reacts easily with acetic anhydride to give phenyl acetate. Likewise, the phenolate anion is an effective nucleophile in S_N2 reactions, as in the second example below.

C₆H₅–OH   +  (CH₃CO)₂O     C₆H₅–O–COCH₃   +  CH₃CO₂H

C₆H₅–O^(–) Na⁽⁺⁾   +  CH₃CH₂CH₃–Br     C₆H₅–O–CH₂CH₂CH₃   +  NaBr