BIOCIDAL WATER-SOLUBLE 3-ISOTHIAZOLONE COMPOSITION

摘要

PROBLEM TO BE SOLVED: To obtain the subject composition, comprising hardly any or no nistrosamine impurity and useful for cosmetics or medicines by using a 3- isothiazolone obtained by cyclizing an intermediate amide prepared by using a specific raw material with a specified metallic nitrate in combination. SOLUTION: This biocidal water-soluble 3-isothiazolone material is prepared by amidating methyl 3-mercaptopropionate represented by formula I, cyclizing the prepared intermediate amide represented by formula II [(n) is 1-3] without substantially containing a nitrosamine precursor with a chlorinating agent and combining the resultant 3-isothiazolone represented by formula III with a metallic nitrate in an amount sufficient to stabilize the 3-isothiazolone. Magnesium nitrate is preferred as the metallic nitrate. A mixture of 60-90wt.% 5-chloro-2- methyl-4-isothiazolon-3-one with 40-10wt.% 2-methyl-4-isothiazolon-3-one is especially preferred as the 3-isothiazolone composition. The content of the nitrosamine impurity or its precursor in the compositin is preferably <=110ppm, especially preferably <=20ppm.