Electrophilic Aromatic Substitution ReactionsCertain compounds (electrophilic) can react with phenols (nucleophilic). The nucleophilic activity can be either in the aromatic ring or the oxygen in the hydroxyl group. Examples of electrophilic aromatic substitution include nitration, halogenation, Friedel-Crafts reactions (alkylation and acylation), and sulfonation. The halogenation example shown below is a polysubstitution reaction involving bromine. The polysubstitution usually occurs when polar solvents are used.
Monobromination can be achieved by using nonpolar solvents.