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Method and device for recycling hydrazine hydrate in preparation process of 3-chloro-2-hydrazinopyridine intermediate

A technology of hydrazine pyridine and hydrazine hydrate, which is applied in the field of recovery and reuse of hydrazine hydrate, can solve the problems of waste of hydrazine hydrate and less effective recovery of hydrazine hydrate, and achieves the effects of saving production cost, improving heat exchange efficiency and promoting effective precipitation

Active Publication Date: 2021-11-30
天长高能环保科技有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

3-Chloro-2-hydrazinopyridine is an intermediate used in the synthesis of the pesticide chlorantraniliprole, and its synthesis method is mainly prepared by reacting 2,3-dichloropyridine with hydrazine hydrate as a raw material. Excessive hydrazine hydrate is required, which will cause a large amount of waste of hydrazine hydrate. In order to reduce the preparation cost of products and protect the environment, it is necessary to effectively recycle hydrazine hydrate and reuse it. However, there are few studies on the effective recovery of hydrazine hydrate at present.

Method used

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  • Method and device for recycling hydrazine hydrate in preparation process of 3-chloro-2-hydrazinopyridine intermediate
  • Method and device for recycling hydrazine hydrate in preparation process of 3-chloro-2-hydrazinopyridine intermediate

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Embodiment 1

[0033] A method for recovering and reusing hydrazine hydrate in a 3-chloro-2-hydrazinopyridine intermediate preparation process, comprising the following steps: adding 1mol / L sodium hydroxide solution to a hydrazine-containing solution to adjust the solution to neutrality, and then adding The cooling coil in the crystallization tank is fed with liquid ammonia to quickly cool down to -3°C, and the precipitate is filtered out. The filtered filtrate is evaporated in the circulating evaporator at 110°C for 1 hour, and the evaporated gas is condensed by the condenser and then re-enters the reused in the reactor.

Embodiment 2

[0035] A method for recovering and reusing hydrazine hydrate in a 3-chloro-2-hydrazinopyridine intermediate preparation process, comprising the following steps: adding 1mol / L sodium hydroxide solution to a hydrazine-containing solution to adjust the solution to neutrality, and then adding Liquid ammonia is passed into the cooling coil in the crystallization kettle to quickly cool down to ~0°C, and the precipitate is removed by filtration. The filtered filtrate is evaporated in the circulating evaporator at 120°C for 2 hours, and the evaporated gas is condensed by the condenser and then re-enters the reused in the reactor.

Embodiment 3

[0037] A method for recovering and reusing hydrazine hydrate in a 3-chloro-2-hydrazinopyridine intermediate preparation process, comprising the following steps: adding 1mol / L sodium hydroxide solution to a hydrazine-containing solution to adjust the solution to neutrality, and then adding The cooling coil in the crystallization kettle is fed with liquid ammonia to quickly cool down to -3°C, and the precipitate is filtered out. The filtered filtrate is evaporated in the circulating evaporator at 120°C for 1 hour, and the evaporated gas is condensed by the condenser and then re-enters the reused in the reactor.

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Abstract

The invention discloses a method for recycling hydrazine hydrate in a preparation process of a 3-chloro-2-hydrazinopyridine intermediate. The method is characterized by comprising the following steps: adding alkali liquor into a hydrazine-containing solution for neutralization, then conducting rapidly cooling to -3 to 0 DEG C, carrying out filtering to remove a precipitate, carrying out evaporation treatment on a filtered filtrate, condensing evaporated gas and then allowing the condensed gas to enterreaction liquid for preparing 3-chloro-2-hydrazinopyridine again to be reused. The method is simple to operate, and hydrazine hydrate can be effectively recycled.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a method and device for recycling hydrazine hydrate in the preparation process of a 3-chloro-2-hydrazinopyridine intermediate. Background technique [0002] Hydrazinopyridine and its halogenated derivatives are a very important class of fine chemical intermediates, widely used in the fields of medicine and pesticides. They can be used to synthesize various heterocyclic compounds such as pyrazoles, pyridazines, and triazoles. 3-Chloro-2-hydrazinopyridine is an intermediate used in the synthesis of the pesticide chlorantraniliprole, and its synthesis method is mainly prepared by reacting 2,3-dichloropyridine with hydrazine hydrate as a raw material. Excessive hydrazine hydrate is required, which will cause a large amount of waste of hydrazine hydrate. In order to reduce the preparation cost of the product and protect the environment, it is necessary to effectively recycl...

Claims

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Application Information

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IPC IPC(8): C01B21/16B01D36/00C07D213/77C09K5/14
CPCC01B21/16C07D213/77B01D36/00C09K5/14
Inventor 孙连兵李偲程鹤鸣万勇
Owner 天长高能环保科技有限责任公司