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Acethydrazide synthesizing method

A technology of acetylhydrazide and hydrazine hydrate, which is applied in the field of synthesizing acetylhydrazine, can solve the problems of environmental pollution, increased reaction steps, and high production costs, and achieve the effects of reducing production costs, shortening reaction steps, and low production costs

Inactive Publication Date: 2018-06-22
重庆晶萃化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, there are two main methods for the synthesis of acetylhydrazide: (1) acetic acid method: the acetic acid method mainly uses acetic acid and hydrazine hydrate as raw materials, and synthesizes acetylhydrazide through hydrazide reaction under the action of a catalyst. The catalyst is expensive, and the recovery of the catalyst is difficult, the post-treatment is complicated, the reaction yield is low (less than 80%), and the production cost is high; (2) Ethyl acetate method: The ethyl acetate method uses ethyl acetate and hydrazine hydrate as raw materials. Using absolute ethanol as a solvent, acetylhydrazide is synthesized through hydrazinolysis reaction. Compared with the acetic acid method, although the yield has been improved, it needs to carry out esterification reaction between acetic acid and ethanol first, which increases the number of reaction steps and increases the yield. In addition, because the esterification reaction uses concentrated sulfuric acid as a catalyst, a large amount of acidic organic wastewater will be produced. After neutralization with alkali, the salt content and COD content in the wastewater are very high, and the wastewater treatment is difficult and expensive. Large amount of waste discharge, easy to cause environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Put 300g of acetic acid, 330g of hydrazine hydrate with a content of 90% and 30g of mordenite molecular sieve into a four-necked flask with stirring, a thermometer and a rectification column, start stirring, heat up to reflux, and when the steam enters the rectification column, Extract water vapor at a column top temperature of 98°C to 100°C, react at reflux temperature for 4 to 6 hours, stop the reaction when no condensed water flows out from the top of the rectification column, continue heating and distillation, and recover at a column top temperature of 110°C to 120°C Unreacted acetic acid and hydrazine hydrate, when the acetic acid and hydrazine hydrate are all evaporated, the liquid in the flask is poured out while hot and filtered to recover the mordenite molecular sieve catalyst, and the filtrate is cooled and crystallized, washed with pure water, and vacuum-dried to obtain acetylhydrazide 336.9 g.

Embodiment 2

[0014] Put 300g of acetic acid, 395g of hydrazine hydrate with a content of 95% and 60g of mordenite molecular sieve into a four-necked flask with stirring, a thermometer and a rectification column, start stirring, heat up to reflux, and when the steam enters the rectification column, Extract water vapor at a column top temperature of 98°C to 100°C, react at reflux temperature for 4 to 6 hours, stop the reaction when no condensed water flows out from the top of the rectification column, continue heating and distillation, and recover at a column top temperature of 110°C to 120°C Unreacted acetic acid and hydrazine hydrate, when the acetic acid and hydrazine hydrate are all evaporated, the liquid in the flask is poured out while hot and filtered to recover the mordenite molecular sieve catalyst, and the filtrate is cooled and crystallized, washed with pure water, and vacuum-dried to obtain acetylhydrazide 344.7g.

Embodiment 3

[0016] Put 300g of acetic acid, 480g of hydrazine hydrate with a content of 99% and 90g of mordenite molecular sieve into a four-necked flask with stirring, a thermometer and a rectification column, start stirring, heat up to reflux, and when the steam enters the rectification column, Extract water vapor at a column top temperature of 98°C to 100°C, react at reflux temperature for 4 to 6 hours, stop the reaction when no condensed water flows out from the top of the rectification column, continue heating and distillation, and recover at a column top temperature of 110°C to 120°C Unreacted acetic acid and hydrazine hydrate, when the acetic acid and hydrazine hydrate are all evaporated, the liquid in the flask is poured out while hot and filtered to recover the mordenite molecular sieve catalyst, and the filtrate is cooled and crystallized, washed with pure water, and vacuum-dried to obtain acetylhydrazide 355.5g.

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Abstract

The invention discloses an acethydrazide synthesizing method. According to the method, acethydrazide is synthesized from acetic acid and hydrazine hydrate as raw materials and a mordenite molecular sieve as a catalyst by reaction at certain temperature. Excessive hydrazine hydrate is maintained in a reaction system, water generated in the reaction is separated out continuously from the reaction system, acetic acid and hydrazine hydrate which do not participate in the reaction are distilled out and recovered after the reaction, the catalyst is recovered by filtering while the reaction system isstill hot, a filtrate is subjected to cooling crystallization, washed with pure water and dried in vacuum, and a finished acethydrazide product is obtained. Compared with the prior art, the mordenitemolecular sieve taken as the catalyst has good catalytic effect, reaction yield is high, the catalyst is easy to recover and recyclable, esterification is omitted, production cost is reduced, waste is not produced or discharged in the reaction process, and the method is an environment-friendly production process.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a method for synthesizing acetylhydrazide. Background technique [0002] Acetylhydrazide is a white crystal with a melting point of 58-68 °C and is easily soluble in water. It is an important chemical raw material and can be used to synthesize analgesics, anticancer drugs, tooth corrosion inhibitors, lamellar activity index inhibitors, Anti-fogging agent, stabilizer for color fixer, metal pickling preservative, etc. In particular, the use of acetylhydrazide as a raw material to prepare carbamate insecticides can avoid the poisoning of human body and environment caused by the direct use of methyl isocyanate. [0003] At present, there are two main methods for the synthesis of acetylhydrazide: (1) acetic acid method: the acetic acid method mainly uses acetic acid and hydrazine hydrate as raw materials, and synthesizes acetylhydrazide through hydrazide reacti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C241/04C07C243/28
CPCC07C241/04C07C243/28
Inventor 不公告发明人
Owner 重庆晶萃化工科技有限公司