What happens if 2,4,6-tribromophenol is forced to undergo further bromination?
In phenol, the benzene ring is activated towards electrophilic substitution. Therefore, phenol on bromination gives 2,4,6-tribromophenol. If now, 2, 4, 6-tribromophenol is forced to undergo bromination, the group attached to the benzene nucleus makes phenol not suitable to undergo Friedel–Crafts reaction due to adduct formation with Lewis acid.