How is 4-(2,4-Dichlorophenoxy)butanoic acid (CAS: 94-82-6) typically synthesized?

4-(2,4-Dichlorophenoxy)butanoic acid is typically synthesized via the reaction of 2,4-dichlorophenol with acetic anhydride followed by hydrolysis. The synthesis involves the condensation of 2,4-dichlorophenol with acetic anhydride, yielding 2,4-dichlorophenylacetic acid, which is then hydrolyzed to give the final product. Commonly, the reaction is performed in the presence of a catalyst such as sulfuric acid or p-toluenesulfonic acid, with high yields and good selectivity.