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Synthesis method of acethydrazide

A synthesis method and technology of acetyl hydrazide, applied in directions such as hydrazide preparation, can solve problems such as complicated process, high production cost, low total yield, etc., and achieve the effects of shortening process steps, eliminating esterification reaction, and reducing production cost

Inactive Publication Date: 2018-07-06
李博强
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of prior art synthesis of acetylhydrazine are as follows: (1) in the first step of esterification reaction, the used catalyst concentrated sulfuric acid is highly corrosive, requires high equipment, and will produce a large amount of acidic organic wastewater. And after the treatment, the salt content and COD content are very high, because the organic wastewater treatment is difficult, the treatment cost is high, and the discharge volume is large, it is easy to cause environmental pollution; (2) There are many operating steps in the preparation of acetylhydrazide by two-step reaction, and the process is cumbersome , complex process, high energy consumption, many impurities in side reactions, low total yield (only 80-90% based on acetic acid), high production cost, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Put 300g of acetic acid, 375g of hydrazine hydrate with a content of 80% and 30g of ZSM-5 acidic zeolite molecular sieve into a four-necked flask equipped with stirring, thermometer and rectification column, start stirring, heat up to reflux, when the steam enters the rectification After the column, extract water vapor at a column top temperature of 98°C to 100°C, and react at the reflux temperature for 4 to 6 hours. When no condensed water flows out from the top of the rectification column, the reaction is over, and continue heating and distillation. Recover acetic acid and hydrazine hydrate that did not participate in the reaction at 120°C. When the acetic acid and hydrazine hydrate were all evaporated, pour out the liquid in the flask and filter it while it was hot. The filtrate was crystallized by cooling, washed with pure water, and dried in vacuum to obtain 342.8g of acetylhydrazide .

Embodiment 2

[0015] Put 300g of acetic acid, 420g of hydrazine hydrate with a content of 90% and 45g of ZSM-5 acidic zeolite molecular sieve into a four-neck flask equipped with stirring, thermometer and rectification column, start stirring, heat up to reflux, when the steam enters the rectification After the column, extract water vapor at a column top temperature of 98°C to 100°C, and react at the reflux temperature for 4 to 6 hours. When no condensed water flows out from the top of the rectification column, the reaction is over, and continue heating and distillation. Recover acetic acid and hydrazine hydrate that did not participate in the reaction at 120°C. When the acetic acid and hydrazine hydrate were completely evaporated, pour out the liquid in the flask and filter it while it was hot. The filtrate was crystallized by cooling, washed with pure water, and dried in vacuum to obtain 348.2 g of acetylhydrazide .

Embodiment 3

[0017] Put 300g of acetic acid, 450g of hydrazine hydrate with a content of 99% and 60g of ZSM-5 acidic zeolite molecular sieve into a four-necked flask equipped with a stirring, thermometer and rectifying column, start stirring, heat up to reflux, and when the steam enters the rectifying After the column, extract water vapor at a column top temperature of 98°C to 100°C, and react at the reflux temperature for 4 to 6 hours. When no condensed water flows out from the top of the rectification column, the reaction is over, and continue heating and distillation. Recover acetic acid and hydrazine hydrate that did not participate in the reaction at 120°C. When the acetic acid and hydrazine hydrate were completely evaporated, pour out the liquid in the flask and filter it while it was hot. The filtrate was crystallized by cooling, washed with pure water, and dried in vacuum to obtain 353.1 g of acetylhydrazide .

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Abstract

The invention discloses a synthesis method of acethydrazide. According to the method, acetic acid and hydrazine hydrate are used as raw materials; a ZSM-5 (Zeolite Socony Mobil-5) acid zeolite molecular sieve is adopted as a catalyst; the acethydrazide is synthesized by a reaction at a certain temperature. The hydrazine hydrate is maintained to be excessive in a reaction system; water generated bythe reaction is continuously separated out from the reaction system; the performing of a hydrazidation reaction is effectively promoted; the reaction time is shortened; the reaction yield is improved. Compared with the prior art, the synthesis method adopts the ZSM-5 (Zeolite Socony Mobil-5) acid zeolite molecular sieve as the catalyst, and is good in catalytic effect and high in reaction yield;the catalyst is easily recovered, and can be repeatedly used; the acetic acid does not need to be esterified; process steps are reduced; the production cost is decreased, the discharge of waste is reduced, and the synthesis method is a green and 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. It is easily soluble in water and is an important chemical raw material. It 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, the synthesis method of acetylhydrazine is mainly based on acetic acid, ethanol and hydrazine hydrate as raw materials, and is obtained through two-step reactions (esterification reaction and hydrazinolysis reaction): the first step...

Claims

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Application Information

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IPC IPC(8): C07C241/04C07C243/28
CPCC07C241/04C07C243/28
Inventor 李博强
Owner 李博强
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