A kind of method for continuously preparing methyl anthranilate

Abstract

The invention relates to the field of biomedicine, more specifically, to a method for continuously preparing methyl anthranilate. In this method, sodium o-formamide benzoate methanol solution and sodium hypochlorite solution prepared by mixing phthalimide, liquid caustic soda, methanol and water are injected into its reaction chamber from one end of a flat tubular reactor, and o-formamide benzoate The injection of sodium formate methanol solution and sodium hypochlorite solution pushes the materials in the reaction chamber to advance to the other end of the tubular reactor while mixing and reacting. Under the agitation of the stirring column vertical to the axial direction of the tubular reactor, they are mixed in the front section of the tubular reactor. The Hofmann degradation reaction is carried out in the middle section and the back section of the tubular reactor, and finally advances to the other end of the tubular reactor to be discharged, and is hydrolyzed to obtain the methyl anthranilate. The method of the invention can eliminate partial back-mixing in the preparation process, has good mass transfer effect, short reaction residence time, high yield, large reaction flux, can avoid reactor clogging, and can be put into continuous large-scale production.

Description

technical field [0001] The invention relates to the field of biomedicine, more specifically, to a method for continuously preparing methyl anthranilate. Background technique [0002] Methyl anthranilate is mainly used as an intermediate in the synthesis of dyes, medicines, pesticides, and spices. In terms of dyes, it is used in the manufacture of azo dyes, anthraquinone dyes, and indigo dyes. In medicine, it is used in the manufacture of antiarrhythmic drugs changroline, vitamin L, non-steroidal anti-inflammatory analgesics mefenamic acid, yantongjing, non-barbiturate hypnotic methaphenone, and strong tranquilizer Thiel ascend. At present, there are mainly two methods for synthesizing methyl anthranilate. One is to perform amidation reaction of phthalic anhydride and ammonia to generate sodium anthranilate, which is degraded by sodium hypochlorite to generate sodium anthranilate, and finally neutralized The other is the reductive esterification of o-nitrobenzoic acid or t...

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Problems solved by technology

But, need variable temperature operation in the preparation methyl anthranilate process, the required temperature of mixing reaction is higher, and neutralization reaction temperature is lower, under this low temperature condition, methyl anthranilate crystallization is separated out, is unfavorable for microchannel The normal operation of the small pipeline of the reactor is easy to be blocked. In addition, the flux of the microchannel reactor is small, which limits the large-scale production application, and it is easy to have uneven mixing during the reaction process, relatively poor heat transfer effect and easy to produce backflow. Mixing phenomenon leads to inconsistencies in the reaction rate at different positions of the reactor, which affects the mass transfer rate and product yield

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