The invention discloses a method for synthesizing 4, 4 '-difluorobenzophenone from
fluorobenzene, which comprises the following steps: 1) adding p-fluorotoluene into a reactor, adding a catalyst and a
solvent, and introducing
oxygen to obtain p-fluorobenzoic acid; 2) adding p-fluorobenzoic acid into a first four-mouth
bottle, then adding
thionyl chloride, and heating by adopting an
oil bath to obtain p-fluorobenzoyl
chloride; 3) adding
fluorobenzene and a
solvent into a second four-opening
bottle, weighing
anhydrous aluminum
chloride, adding the weighed
anhydrous aluminum chloride into the second four-opening
bottle, adding p-fluorobenzoyl chloride into the second four-opening bottle, and heating in a water bath; 4) after the reaction is finished, pouring into
ice water, stirring, layering, separating liquid, and washing with water to separate an
oil phase; and 5) adding the
oil phase into a third four-neck flask for
distillation, adding
methanol and
activated carbon, decolorizing, carrying out suction
filtration, crystallizing and
drying to obtain the 4, 4 '-difluorobenzophenone. The process steps are simple, the purity of the 4, 4 '-difluorobenzophenone product is higher than 99%, the yield is 90% or above, byproducts are reduced, the purification difficulty is low, and the industrial production cost is reduced.