Apparatus for improving content of sulfonamide through base-dissolving acidification, and method thereof

Abstract

The invention discloses an apparatus for improving the content of sulfonamide through base-dissolving acidification. The apparatus comprises a base dissolving kettle, an acidification kettle, a filter, a hydrochloric acid tank and a pressure pump. The invention also provides a method for improving the content of sulfonamide through base-dissolving acidification. The method comprises the following steps: adding water and liquid caustic soda into the base dissolving kettle, adding crude o / p-toluenesulfonamide, heating, carrying out heat insulation, filtering by using the filter to make the obtained base solution enter the acidification kettle and obtain a filter intercepted filter cake layer which is an insoluble substance diphenyl sulfone, adding hydrochloric acid in a dropwise manner while stirring to adjust the pH value of the obtained base solution to 1-3 in order to completely precipitate o / p-toluenesulfonamide dissolved in the base solution, centrifuging, carrying out solid-liquid separation to obtain o / p-toluenesulfonamide with the content reaching above 98.5%, and re-crystallizing by using methanol to obtain a high-quality o / p-toluenesulfonamide product. Xylyl phenyl sulfone is insoluble in the base solution, and o / p-toluenesulfonamide is soluble in the base solution, so xylyl phenyl sulfone can be removed by using the base solution.

Description

technical field [0001] The invention relates to a device for increasing the content of sulfonamide through alkali dissolution and acid precipitation. [0002] The invention also relates to a method for increasing the content of sulfonamide through alkali dissolution and acid precipitation. Background technique [0003] The current process for producing o-p-toluenesulfonamide is obtained by amination of o-p-toluenesulfonyl chloride and ammonia water. Add water into the reaction kettle as a slow-release solvent, add measured ammonia water into the reaction kettle, add o-p-toluenesulfonyl chloride dropwise at below 50°C for amination to obtain o-p-toluenesulfonamide, and then obtain o-p-toluenesulfonamide by centrifuging solid-liquid separation The crude product of p-toluenesulfonamide was recrystallized from methanol to obtain the fine product of o-p-toluenesulfonamide. [0004] Since o-p-toluenesulfonyl chloride is obtained by sulfonation of toluene and chlorosulfonic acid ...

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Problems solved by technology

[0004] Since o-p-toluenesulfonyl chloride is obtained by sulfonation of toluene and chlorosulfonic acid at low temperature, a side reaction of sulfonyl chloride and toluene Friedel-Crafts reaction will occur in the sulfonation process to produce xylylphenyl sulfone, and the content of o-p-toluenesulfonyl chloride can only be Reach 93~95%, so the content of the crude o-toluenesulfonamide obtained after amination is less than 95%, and it is difficult to purify to more than 99% by methanol recrystallization, and the production cost is relatively high

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