Method for preparing diisopropyl phosphite

Abstract

The invention relates to a method for preparing diisopropyl phosphate via the esterification of phosphorus trichloride and isopropanol, which comprises adding phosphorus trichloride into benzene solvent to form a first mixture, adding benzene, isopropanol and weak alkaline organic catalyst into a reactor to form a second mixture, slowly adding the first mixture into the second mixture to form a reaction system, increasing and controlling temperature, reacting for 4.5-9h to obtain the mixture containing diisopropyl phosphate, deacidifying the mixture via pure alkali, filtering, distilling, depressurizing and distilling to obtain final diisopropyl phosphate product. The preparation method has low cost and high yield.

Description

technical field [0001] The invention relates to a preparation method of phosphite. Background technique [0002] Both phosphite and phosphate are intermediates for the preparation of organophosphorus pesticides. At present, when preparing (phosphite) esters, phosphorus trichloride, phosphorus oxychloride or phosphorus thionium chloride are generally used for esterification reaction with alcohols (such as methanol, ethanol) or phenols (such as phenol), and the reaction releases hydrogen chloride. And other chlorides; the mixture containing liquid hydrogen chloride and crude ester generated by the reaction is deacidified (that is, the mixture flows into the deacidification tank after being cooled by the condenser, and is heated and deacidified) to obtain the crude (phosphite) ester . The crude product is subjected to fractional distillation under reduced pressure to obtain the corresponding pure (phosphite) ester. In this preparation method, because the esterification react...

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Problems solved by technology

[0004] The Chinese invention patent with the patent number "02146607.6" discloses a method for preparing phosphite, which uses a mixed solution composed of a weak acid salt of ammonium and phosphite to react the reaction system during the esterification reaction. Cooling is carried out to weaken the decomposition of hydrogen chloride to phosphate, and ammonia gas deacidification is used to ensure the yield of phosphite, and diisopropyl phosphite is prepared by this method, using weak acid salt of ammonium and phosphite The premise of cooling the reaction system by the mixed liquid formed is first to obtain phosphite by other methods, which undoubtedly brings about cost increase and complicated operation. In addition, the use of ammonia gas for deacidification, although the yield can be guaranteed to a certain extent, But the equipment cost is higher