Synthetic method of CLT acid

The invention belongs to the field of synthesis, and particularly relates to a CLT acid synthesis method which comprises the following steps: step 1, sulfonylation reaction: enabling m-toluidine and sulfuric acid to react to form sulfonylation reaction liquid; step 2, chlorination reaction: uniformly stirring the acylation reaction solution and ferric chloride, slowly introducing chlorine gas for reaction, and filtering after the reaction is finished to obtain a chlorination reaction solution; 3, transposition sulfonation: adding o-dichlorobenzene into the chlorination reaction liquid, carrying out heating reaction treatment for 5-8 hours, and stopping heating to obtain sulfonation reaction liquid; and step 4, performing post-treatment on the sulfonation reaction liquid to obtain a finished product CLT acid. According to the method, the defects of the existing CLT acid process are overcome, the synthesis of the CLT acid is realized by utilizing a one-pot method, intermediate transfer treatment is not needed,