The invention relates to a synthetic method of p-chlorophenylboronic acid, which belongs to the technical field of
organic synthesis, and comprises the following steps: S1, synthesis of p-chlorophenylboronic acid: adding
magnesium chips and
anhydrous tetrahydrofuran into a reaction container, adding p-bromochlorobenzene in batches while stirring, automatically initiating a reaction liquid, heating and blackening, stopping adding p-bromochlorobenzene, and cooling to
room temperature to obtain p-chlorophenylboronic acid; adding p-bromochlorobenzene when the temperature is reduced to 60 DEG C, repeating the operation, adding p-bromochlorobenzene until all p-bromochlorobenzene is added, carrying out cold bath when the temperature is reduced to 40 DEG C, adding
trimethyl borate at 10-15 DEG C, and continuing stirring when the
reaction system becomes viscous; and S2, purification of p-chlorophenylboronic acid: adding a
hydrochloric acid aqueous solution, stirring, standing to separate out organic phases, extracting a
water layer with
ethyl acetate, combining the organic phases,
drying with
anhydrous sodium sulfate, filtering, reducing pressure to remove the
solvent to obtain white solids, and
drying overnight to obtain gray solids, namely p-chlorophenylboronic acid. The method is simple in process step, safe and
environmentally friendly, and the chromatographic purity of the prepared p-chlorophenylboronic acid can reach 99.0% or above.