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Method for reducing carbendazim impurity DAP in production process of carbendazim

A production process and technology of carbendazim, applied in the field of carbendazim production, can solve the problem of high DAP content and achieve the effect of improving quality

Inactive Publication Date: 2015-10-07
ANHUI DONGZHI GUANGXIN AGROCHEMICAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The traditional DAP control method is mainly to control the effect of the rectification tower in the early stage, but when the rectification effect is not good, the DAP content in the carbendazim product is relatively high, and the content after rectification is even higher

Method used

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  • Method for reducing carbendazim impurity DAP in production process of carbendazim

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] First carry out the synthesis of o-phenylenediamine; carry out the synthesis of methyl cyanamide; then carry out the synthesis of carbendazim: o-phenylenediamine and methyl cyanamide are transferred to the reactor for complexation reaction, and Add dropwise hydrochloric acid while the complexation reaction, and dropwise add hydrochloric acid at the end of the condensation, the pH in the reactor is 4.2 at this time, and relatively stable, then add 2.5kg of additive paraformaldehyde in the reactor, open the reactor stirring device to fully Stir, keep warm, and the temperature is 98 ° C, the holding time is 60 minutes, then filter the materials in the reactor, wash the filtered materials with water, then drain the washed materials, and finally drain the dried materials After drying, the DAP content reaches about 0.5ppm after rectification, and DAP does not rebound after being placed overnight, which can better meet the production requirements, that is, add additional additi...

Embodiment 2

[0020] First carry out the synthesis of o-phenylenediamine; carry out the synthesis of methyl cyanamide; then carry out the synthesis of carbendazim: o-phenylenediamine and methyl cyanamide are transferred to the reactor for complexation reaction, and Add hydrochloric acid dropwise while the complexation reaction, and drop hydrochloric acid at the end of condensation, at this moment, the pH in the reactor is 4.3, and relatively stable, then add the additive paraformaldehyde of 2.4kg in the reactor, open the reactor stirring device to carry out fully Stir, keep warm, and the temperature is 96°C, the holding time is 40min, then filter the material in the reactor, wash the filtered material with water, then drain the washed material, and finally drain the dried material After drying, the DAP content can reach about 0.5ppm after rectification, and the DAP will not rebound after being left overnight, which can better meet the production requirements, that is, add additives after the...

Embodiment 3

[0022] First carry out the synthesis of o-phenylenediamine; carry out the synthesis of methyl cyanamide; then carry out the synthesis of carbendazim: o-phenylenediamine and methyl cyanamide are transferred to the reactor for complexation reaction, and Add hydrochloric acid dropwise while the complexation reaction, and drop hydrochloric acid at the end of the condensation, the pH in the reactor is 4.4 at this time, and relatively stable, then add 2.3kg of additive paraformaldehyde in the reactor, open the reactor stirring device to fully Stir, keep warm, and the temperature is 95 ° C, the holding time is 30 minutes, then filter the materials in the reaction kettle, wash the filtered materials with water, then drain the washed materials, and finally drain the dried materials After drying, the DAP content reaches about 0.5ppm after rectification, and DAP does not rebound after being placed overnight, which can better meet the production requirements, that is, add additional additi...

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Abstract

The invention provides a method for reducing a carbendazim impurity DAP in the production process of carbendazim. The method includes: synthesizing o-phenylenediamie; synthesizing cyanamide based methyl formate; synthesizing carbendazim, namely transferring o-phenylenediamie and cyanamide based methyl formate into a reaction kettle for complexation, dropwise adding hydrochloric acid during complexation, adding an additive into the reaction kettle after dropwise condensation adding of hydrochloric acid is finished, starting a reaction kettle stirring device for sufficient stirring, maintaining temperature, filtering, using water for washing, swabbing-off and drying. The additive is added after condensation is finished on the basis of controlling DAP content, the DAP content can reach level A+ after material drying, the DAP content reaches about 0.5ppm after testing and rectification, DAP does not rebound after overnight placement, production requirements can be met better, and content of the impurity in the carbendazim is lowered. Consequently, through testing, the DAP content of carbendazim raw materials is lowered to be about 0.2ppm, so that quality is improved, carbendazim content is improved from 95% to 96.3%, and DAP+HAP is smaller than or equal to 1.5mg / kg.

Description

technical field [0001] The invention relates to the field of carbendazim production, in particular to a method for reducing carbendazim impurity DAP in the production process of carbendazim. Background technique [0002] 2,3 Diaminophenazine (DAP) is an important impurity in the finished product of carbendazim, and its impurity content directly affects the quality of carbendazim; by adding complexing agent, the content of carbendazim impurity is greatly reduced. [0003] The traditional DAP control method is mainly to control the effect of the rectification tower in the early stage, but when the rectification effect is not good, the DAP content in the carbendazim product is relatively high, and the content after the rectification is even higher. Contents of the invention [0004] Aiming at the above problems in the prior art, the present invention provides a method for reducing the impurity DAP of carbendazim in the production process of carbendazim, so as to reduce the co...

Claims

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Application Information

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IPC IPC(8): C07D235/32
CPCC07D235/32
Inventor 钱潮涌章子虎高伟黄晓平刘纯虎徐长胜高焰兵
Owner ANHUI DONGZHI GUANGXIN AGROCHEMICAL CO LTD
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