PURPOSE: When crude 2-aminothiazole is purified by distillation, boric acid, sodium bisulfite and/or a phosphorous ester are added to the distillation system to inhibit the decomposition of 2-aminothiazole, thus increasing its recovery yield.
CONSTITUTION: For example, crude 2-aminothiazole is obtained by reaction of a chlorination product of vinyl acetate with thiourea in an aqueous medium followed by neutralization of the reaction product with caustic soda or so and it is subjected to disillation in the presence of a compound selected from boric acid, sodium sulfite and phosphorus esters of (RO)3P for purification. Thus, the high-purification 2-aminothiazole is obtained as the column top fraction and used as a diazo component of monoazoe dyes. The total amount of the compounds added for purification is preferably 0.5W1wt% based on 2-aminothiazole and almost all of them remain in the bottom on distillation.
SHINTANI TOSHISHIO
KAJIKAWA AKIRA
