Patent ID: 8507691

Claim:
A process for producing 3-isothiazolinone derivatives, comprising continuously carrying out the following four steps: (1) continuously adding a compound of formula I, sulfur and H 2 S to a first reaction device to obtain a first reaction solution comprising a compound of formula II and a compound of formula III by way of a first reaction: wherein the first reaction is carried out in an aqueous solution of ammonium sulfide; (2) continuously adding the first reaction solution and an aqueous solution of sodium sulfite to a second reaction device to obtain a second reaction solution comprising a compound of formula II by way of a second reaction: wherein step (2) comprises i) continuously adding a mixture of a compound of formula II and a compound of formula III and an aqueous solution of sodium sulfite to a first counter-current extraction column; and ii) continuously adding the organic phase obtained from step i) and water to a second counter-current extraction column to obtain the compound of formula II; (3) continuously adding the second reaction solution and a primary amine of formula IV to a third reaction device to obtain a compound of formula V by way of a third reaction: wherein R represents C 1 -C 18 alkyl or C 3 -C 18 cycloalkyl; and (4) continuously adding the compound of formula V and chlorine to a fourth reaction device to obtain a compound of formula VI by way of a fourth reaction: R represents C 1 -C 18 alkyl or C 3 -C 18 cycloalkyl, and R 1 and R 2 independently represent H or chlorine, and the fourth reaction is carried out in the presence of an ester.