Preparation method of cresyl diphenyl phosphate

Abstract

The invention relates to a preparation method of cresyl diphenyl phosphate. The method includes the steps of: 1) esterification reaction: mixing phosphorus oxychloride with a catalyst, then adding phenol dropwise, and at the end of the reaction, conducting reduced pressure distillation to obtain diphenoxy phosphoryl chloride; 2) reduced pressure reaction: reacting the intermediate diphenoxy phosphoryl chloride obtain in step 1) with m, p-cresol under a reduced pressure, and removing the reacted hydrogen chloride gas to obtain a cresyl diphenyl phosphate crude product; and 3) refining: carryingout alkali washing, washing and reduced pressure distillation on the cresyl diphenyl phosphate crude product obtained in step 2) to obtain cresyl diphenyl phosphate. Phosphorus oxychloride and phenolare employed for reaction to prepare the diphenoxy phosphoryl chloride intermediate, the generated intermediate reacts with m, p-cresol to prepare the product, the synthetic route reduces the impurities phenyl xylylphosphate, tricresyl phosphate and triphenyl phosphate, thus improving the purity.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a preparation method of toluene-diphenyl phosphate. Background technique [0002] Cresyl-diphenyl phosphate (referred to as CDP flame retardant), can also be cresyl diphenyl phosphate, cresyl diphenyl phosphate or phenylmethylphenyl phosphate, the English name is Cresyl Diphenyl Phosphate, and the CAS registration number is 26444 -49-5 molecular formula: C 19 h 17 o 4 P, molecular weight: 340.31, its structural formula is as follows: [0003] [0004] Colorless or yellowish transparent liquid, melting point: -38°C boiling point: 235-255°C, density: 1.20, slightly phenolic smell; has good flame retardant and plasticizing properties, mainly used for PVC, VC copolymer, nitrocellulose , cellulose acetate, butyl acetate cellulose, natural and synthetic rubber, etc. [0005] Currently about preparation methods such as: [0006] The method disclosed in Chinese patent ...

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Problems solved by technology

[0008] In the above-mentioned method: usually phenol and m-p-cresol mix, then add phosphorus oxychloride, but phosphorus oxychloride and phenol, the activity of the reaction of m-p-cresol are different, and the reaction of phenol and m-p-cresol is fast, and m-p-cresol P-cresol is slow, and the products produced by the reaction contain products with different components. Phenol and phosphorus oxychloride generate triphenyl phosphate, m-p-cresol and phosphorus oxychloride generate tricresyl phosphate, of which triphenyl phosphate, diphosphate Cresyl phenyl ester, tricresyl phosphate, the main component is about 95% of toluene-diphenyl phosphate, because the product contains xylyl phenyl phosphate, tricresyl phosphate, and triphenyl phosphate impurities, which limit some application fields In the field of military industry and aviation, the base oil in the speed control system of large power generating units is required to have high purity, good thermal stability and durability

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