How do phenols typically react during electrophilic substitution?

Phenols typically react during electrophilic substitution by activating the aromatic ring and directing further substitutions to specific positions on the ring. The presence of the hydroxyl (-OH) group in phenols enhances the electron density of the aromatic system due to resonance. This means that when an electrophile approaches the ring, the increased electron density makes it more likely for the electrophile to attack, thus facilitating electrophilic substitution reactions.

The hydroxyl group also influences the position where substitutions occur, primarily directing them to the ortho and para positions relative to itself. The reason for this preferential directing is again linked to the resonance stabilization provided by the hydroxyl group, which can delocalize positive charge generated during the formation of the sigma complex intermediate. This characteristic makes phenols more reactive than unsubstituted aromatic compounds.

The other options do not accurately describe the behavior of phenols. For instance, phenols do not deactivate the aromatic ring; instead, they significantly enhance its reactivity. Additionally, while electrophilic substitution is indeed a key aspect of aromatic chemistry, it is not correct to say that phenols do not participate in these reactions. Finally, the notion that phenols always form a stable dimer is misleading, as dimerization is not a characteristic reaction of