The invention discloses a preparation method of a phosphite
antioxidant 168 and belongs to the technical field of
antioxidant preparation. The preparation method is as follows: adding excessive 2,4-di-tert-butylphenol and a catalyst into a reaction kettle, adding
phosphorus trichloride, and carrying out a synthetic reaction to generate tri(2,4-di-tert-butyl)phosphite; then, adding an anti-hydrolytic agent, then, carrying out
filtration, and evaporating the excessive 2,4-di-tert-butylphenol in filtrate to obtain a crude product of tri(2,4-di-tert-butyl)phosphite; and then, crystallizing the crude product, and carrying out centrifuging, washing and
drying to obtain a final finished product. By using the preparation method of the phosphite
antioxidant 168, the consumption of raw materials isreduced, a reaction
solvent is reduced, the reaction time is shortened, and the generation amount of byproducts is low; and a phosphite antioxidant 168 product prepared by using the preparation methodhas the characteristics of high purity (larger than or equal to 99%, low
acid value (smaller than or equal to 0.3 mgKOH / g) and good
hydrolysis resistance (PH is larger than or equal to 7).