How is 2,4-Dichloro-5-fluorobenzoic acid (CAS: 86522-89-6) typically synthesized?

2,4-Dichloro-5-fluorobenzoic acid is typically synthesized by the reaction of 4-chloro-5-fluorobenzoic acid with chlorine gas. The reaction involves chlorination at the 2-position, followed by the removal of the hydrogen from the carboxylic acid group to form the acid chloride intermediate, which is then hydrolyzed to yield the desired product. The use of aluminum chloride as a catalyst can improve the selectivity and yield of the reaction.