Phenol on reaction with Br2 in CS2∕273K undergoes an electrophilic substitution reaction by Br+(electrophile) in aprotic solvent CS2 to give 4-bromophenol as the major product.
Phenol on reaction withCHCl3,NaOH followed by hydrolysis gives Phenol on reaction with CHCl3,Na salicylaldehyde as a major product. It is Reimer-Tiemann reaction. It is also an electrophilic substitution reaction of phenol by dichlorocarbene CCl2 (electrophilic).