Synthesis method of Tricresyl phosphate

Synthesis method of Tricresyl phosphate:
(1) Catalytic synthesis of Tricresyl phosphate by immobilized heteropolyacid salt:
(1) Preparation of supported heteropolyacid salt catalyst: Take a certain amount of TiCl4, add 12% ammonia water to adjust the pH to 7-8, precipitate, filter and wash until Cl ion is checked with 0.1 mol/LAg NO3. drying. The above raw materials were reacted with a certain amount of pre-heat treated H4SiW12O40·ηH2O for 1.5 h, and the whole process solution was kept in a near-boiling state, and the water was slowly distilled off and dried to obtain a catalyst having a composition of TiSiW12O40/TiO2.
(2) Synthesis: adding quantitative cresol to the reactor, preparing the prepared TiSiW12O40/TiO2 catalyst (1.0% of the total amount of raw materials), stirring, heating to 60 ° C, starting to add phosphorus oxychloride, adding in about 1 h . The reaction was continued to 100 ° C, and the humidity was controlled at 100-120 ° C until substantially no HCI evolution, and the reaction was about 8 h. The catalyst was filtered off, and then the fraction was distilled off under reduced pressure to obtain Tricresyl phosphate.
(2) Indirect synthesis of Tricresyl phosphate by phosphorus trichloride:
Mixed cresol and phosphorus trichloride are reacted at 15-20 ° C to form tricresyl phosphite; then chlorine gas is introduced at 60-70 ° C to form tricresyl dichlorophosphite; hydrolysis is further carried out at 50 ° C And produces tricresyl phosphate. Finally, the water was washed, neutralized, evaporated and dehydrated, and distilled under reduced pressure, and the fraction of 340-360 ° CkPa was taken as the finished Tricresyl phosphate.
Purification method: It is difficult to separate the isomers, and impurities other than the isomers are generally removed only under reduced pressure.