Method for significant reduction of solvent dosage in oxfendazole production process

A technology of production process and usage amount, applied in the field of counter investment, can solve the problems of uneconomical, increased solvent amount, difficult to tolerate B crystal form crystal precipitation, etc. Effect

Inactive Publication Date: 2017-02-08
JIANGSU BAOZONG & BAODA PHARMACHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The fenbendazole produced by the existing technology mainly exists in the A crystal form, so when fenbendazole is first put into the solvent, it is relatively easy to dissolve, but in the solution state, a small number of crystal nuclei of the B crystal form will be formed quickly, thus Induced crystallization, resulting in the precipitation of a large number of intolerant Form B crystals
In order to prevent a large amount of solids from being precipitated in the reaction from affecting the reaction, the only way to increase the amount of solvent is to increase the amount of solvent. Generally, the amount of solvent used is 3 to 4 times that of the material. A large amount of solvent is used and cannot be recovered, which is neither economical nor environmentally friendly.

Method used

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  • Method for significant reduction of solvent dosage in oxfendazole production process

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Add 100.0g of fenbendazole and 400.0g of formic acid into a 1000ml four-necked flask with a thermometer and a stirring device, start stirring, and start adding 41.3Kg of hydrogen peroxide (concentration: 27.5%) dropwise after the material is dissolved, keeping the temperature at 20 ~ 25°C, about 1.5 hours to complete the dropwise addition, after the addition of hydrogen peroxide is completed, add 100.0 g of fenbendazole to the reaction system, and after the added fenbendazole is dissolved, start to drop 57.8Kg of hydrogen peroxide (concentration is 27.5% ), the temperature was kept at 20-25°C, and the dropwise addition was completed in about 1.5 hours. After the hydrogen peroxide was added dropwise, samples were taken and controlled. After the reaction was completed, 70.0 g of sodium sulfite aqueous solution (concentration: 16.5%) was added to the system to quench the reaction. Then concentrate the solvent by distillation under reduced pressure. After the solvent distil...

Embodiment 2

[0028] Add 100.0g of fenbendazole and 400.0g of mixed solvent (ethanol:concentrated sulfuric acid=20:1) into a 1000ml four-necked flask with a thermometer and a stirring device, start stirring, and start adding 41.3Kg of hydrogen peroxide ( The concentration is 27.5%), the temperature is kept at 20 ~ 25 ℃, and the dropwise addition is completed in about 1.5 hours. After the addition of hydrogen peroxide is completed, 100.0 fenbendazole is added to the reaction system. After the added fenbendazole is dissolved, start Add 57.8Kg of hydrogen peroxide (concentration: 27.5%) dropwise, keep the temperature at 20-25°C, and complete the dropwise addition in about 1.5 hours. After the hydrogen peroxide was added dropwise, the sample was controlled in the center. After the reaction was completed, 70.0 g of sodium sulfite aqueous solution (concentration: 16.5%) was added to the system to quench the reaction. Then 41.0 g of ammonia water (concentration is 25.0%) was added dropwise to the ...

Embodiment 3

[0031] Add 100.0g fenbendazole and 400.0g mixed solvent (ethanol: chloroform: concentrated hydrochloric acid = 2:2:1) into a 1000ml four-neck flask with a thermometer and a stirring device, start stirring, and start dripping after the material is dissolved Add 41.3Kg of hydrogen peroxide (concentration: 27.5%), keep the temperature at 20-25°C, and complete the dropwise addition in about 1.5 hours. After the addition of hydrogen peroxide is completed, add 100.0 g of fenbendazole to the reaction system. The fenbendazole to be added After the azole is dissolved, start to add 57.8Kg of hydrogen peroxide (concentration: 27.5%) dropwise, keep the temperature at 20-25°C, and complete the dropwise addition in about 1.5 hours. After the hydrogen peroxide was added dropwise, the sample was controlled in the center. After the reaction was completed, 70.0 g of sodium sulfite aqueous solution (concentration: 16.5%) was added to the system to quench the reaction. Then add 65.0g of ammonia w...

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Abstract

The invention discloses a method for significant reduction of solvent dosage in an oxfendazole production process. In the oxfendazole production process adopting fenbendazole as the starting material and using hydrogen peroxide as the oxidant, because of the poor solubility of fenbendazole, large solvent dosage and no recoverability, the process is high in cost and is environmentally unfriendly. According to the characteristics of material crystal transformation, through ingenious design of the feeding sequence, feeding mode, feeding amount and feeding time, the solvent dosage can be greatly saved. The process is simple to operate, also is economical and environmentally friendly, and is suitable for industrial production.

Description

technical field [0001] The invention relates to a method for greatly reducing the amount of solvent used in the production process of oxfendazole, in particular to [0002] The improvement of the feeding process is an ingenious and innovative feeding process design. Background technique [0003] Oxfendazole is a derivative of fenbendazole, which is a broad-spectrum, high-efficiency, and low-toxic new antihelminth drug. Its anthelmintic spectrum is roughly the same as fenbendazole, but its anthelmintic activity is stronger. Bendazole is used as a raw material, and hydrogen peroxide is used as an oxidizing agent. It is synthesized through an oxidation reaction. The reaction formula is as follows: [0004] . [0005] Due to the poor solubility of fenbendazole, the amount of solvent used in the reaction process is relatively large and cannot be recovered. after research, [0006] We found that the solubility of fenbendazole is not good, mainly because there are two crystal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D235/32
CPCC07D235/32
Inventor 王琳
Owner JIANGSU BAOZONG & BAODA PHARMACHEM
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