Novel crystallizing method of p-acetamidobenzene sulfonyl chloride

Abstract

The invention relates to the technical field of chemical purification, and discloses a novel crystallizing method of p-acetamidobenzene sulfonyl chloride. The method includes the steps of adding acetanilide and chlorosulfonic acid into a reaction still to be stirred to form first-stage slurry, conducting continuous thermal insulation stirring to form second-stage slurry, adding ice water to the second-stage slurry to form third-stage slurry, introducing the third-stage slurry into a first-stage vacuum crystallizer, gradually concentrating the third-stage slurry to finally form first-stage magma, and gradually separating crystal grains out of the first-stage magma. By arranging the first-stage vacuum crystallizer and a second-stage vacuum crystallizer, the third-stage slurry and acid liquorare automatically cooled, no heat exchange face needs to be arranged, it is avoided that a large amount of crystal scales are generated by crystal grains on the heat exchange face, and the number andgrowth speed of crystal nucleus are more conveniently controlled; by means of a first-stage ultrasonic auxiliary crystallizer and a second-stage ultrasonic auxiliary crystallizer, the nucleating speed is high, the crystallizing time is shortened, and the prepared crystal grains are uniform in size.

Description

Technical field [0001] The invention relates to the technical field of chemical purification, in particular to a novel crystallization method of paraacetamidobenzenesulfonyl chloride. Background technique [0002] Paraacetamidobenzene sulfonyl chloride is an important chemical intermediate. It is a commonly used pharmaceutical intermediate for the preparation of sulfa bactericidal and fungicidal drugs. It can be used directly to synthesize dyes, and can also be used to synthesize para esters and para amino oils. Dyestuff intermediates are widely used in the fields of medicine, coatings, plastics and pesticides. At present, most of the production of acetaminobenzene sulfonyl chloride adopts the traditional process of excess chlorosulfonic acid method. The synthetic intermediate product hydrolyzed material needs to be diluted with water to precipitate For paraacetamidobenzene sulfonyl chloride crystals, a common method is to use a stirred dilution kettle, storage tank and discharge...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the deficiencies of the prior art, the present invention provides a new crystallization method for acetaminobenzenesulfonyl chloride, which has the advantages of uniform grain size, fast crystallization speed, and not easy to scale, and solves the problem that the solution is easily affected by the temperature of the cooling liquid and Problems with easy fouling, non-uniform grain size, and longer crystallization times