The invention provides a synthetic method for 1,2,4-trifluorobenzene, belongs to the field of
pesticide,
medicine, and
liquid crystal material intermediate preparation, and solves the problem of harshreaction conditions of a current method for synthesizing 1,2,4-trifluorobenzene. The synthetic method for the 1,2,4-trifluorobenzene is characterized by comprising the following steps: performing
nitration by using 2,4-dichlorofluorobenzene as a
raw material and
nitric acid as a nitrating agent to form 2,4-dichloro-5-fluoronitrobenzene in the presence of
sulfuric acid; dissolving the 2,4-dichloro-5-fluoronitrobenzene into an
organic solvent, adding
potassium fluoride and a first catalyst, and performing fluorination under the
catalysis of the first catalyst to obtain 2,4,5-trifluoronitrobenzene; dissolving the 2,4,5-trifluoronitrobenzene into a
solvent, and performing hydrogenation reduction with
hydrogen under the
catalysis of a second catalyst to obtain 2,4,5-trifluoroaniline; and performing a reaction on the 2,4,5-trifluoroaniline and
sulfuric acid, after a salt is formed, performing a diazotization reaction on the salt and
nitroso-
sulfuric acid, performing a
deamination reductionreaction with
sodium hypophosphite under the
catalysis of a
copper salt, and finally performing
steam distillation to obtain the 1,2,4-trifluorobenzene. The method provided by the invention has the advantages of mild
reaction conditions and the like