PURPOSE: To obtain high purity chlorophosphite useful as a raw material of organophosphorus pesticides, in a short time, in high yield, by reacting phosphorus trichloride with phosphorous acid triester in the presence of a lactam having a specific structure.
CONSTITUTION: The objective compound of formula II[R' is RO or Cl (R is (substituted) alkyl or (substituted) phenyl]is obtained by (1) dissolving or dispersing (A) one or more lactams of formulaI(R" is H or 1W5C alkyl; n is 1W 5) (e.g. -caprolactam) as a catalyst in (B) a phosphorous acid triester of formula (RO)3P at a concentration of 0.5W15wt%, and (2) adding (C) phosphorus trichloride to the solution and reacting at -30W+80°C. When the molar ratio of C/B is 1/(1.8W2.2), the resultant compound is chlorophosphite, and when it is 1/(0.45W0.55), the product is dichlorophosphite.
OOTSUBO ITARU
HASHIMOTO MICHINORI
