The invention discloses a preparation method of a phosphite
antioxidant P-EPQ, and relates to the technical field of antioxidants. The preparation method comprises the following steps: sequentially weighing
biphenyl and
phosphorus trichloride, adding into a reaction flask, stirring and dissolving at
room temperature, adding a catalyst A, stirring and heating, controlling the
internal temperature to be 70-76 DEG C, condensing and refluxing
phosphorus trichloride, reacting for a certain time, stopping the reaction, and distilling to obtain a product which is an intermediate 4, 4 '-
biphenyl bis-
phosphine dichloride; the method comprises the following steps: transferring an intermediate 4, 4 '-
biphenyl bis-dichlorophosphine into a three-neck flask, filling a
mixed solution of 2, 4-di-tert-butylphenol and a catalyst B into a constant-pressure
dropping funnel, dropwise adding the
mixed solution into a reaction flask, keeping the temperature for reaction after the dropwise addition is completed, adding a
solvent into a reaction solution after the reaction is stopped, raising the
internal temperature, stirring and dissolving, carrying out suction
filtration on the solution in the reaction flask, and
drying to obtain the 2, 4'-biphenyl bis-dichlorophosphine. And carrying out negative pressure rotary
evaporation on the filtrate to remove the
solvent, wherein the distilled product is the target product P-EPQ. The preparation method of the
antioxidant P-EPQ provided by the invention has relatively high yield.