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Method for preparing 3-chlorophenylhydrazine sulfate

The technology of chlorophenylhydrazine and sulfate, which is applied in the field of preparation of organic compounds, can solve the problems of high impurity content, poor stability and small yield of products, and achieve the effects of improving purity, easy operation and less impurities.

Inactive Publication Date: 2015-12-30
TIANJIN CHEM REAGENT RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

And the product impurity content made by the preparation method of existing 3-chlorophenylhydrazine sulfate is high, purity is low, stability is poor, yield is little, can not satisfy the needs of market

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A preparation method for 3-chlorophenylhydrazine sulfate, comprising the following steps:

[0023] ⑴ diazotization

[0024] Add 50g of 3-chloroaniline and 150ml of 37% concentrated hydrochloric acid into a 1L three-necked flask, cool to 2°C with ice salt, add 85.7g of 35% sodium nitrite aqueous solution while stirring, and keep the temperature at 2°C for 1 hour.

[0025] ⑵ reduction

[0026] Add 450ml of 37% concentrated hydrochloric acid, 450ml of water and 120g of zinc powder in the reaction solution, keep the temperature at 18°C ​​and react until the reaction is complete, the reaction solution becomes off-white, then add 20% sodium hydroxide solution until the pH value of the reaction solution is 10, After 1 hour of heat preservation at 5°C, crystals were precipitated, and 26.4 g of crude 3-chlorophenylhydrazine was obtained by filtration.

[0027] ⑶ Purification

[0028] Dissolve 26.4g of crude 3-chlorophenylhydrazine in 528g of water, heat it to 60°C to dissolve...

Embodiment 2

[0032] A preparation method for 3-chlorophenylhydrazine sulfate, comprising the following steps:

[0033] ⑴ diazotization

[0034] Add 200g of 3-chloroaniline and 600ml of 37% concentrated hydrochloric acid into a 5L three-necked flask, cool to 2°C with ice salt, add 343g of 35% sodium nitrite aqueous solution while stirring, and keep the temperature at 2°C for 1.5 hours.

[0035] ⑵ reduction

[0036] Add 730ml of 37% concentrated hydrochloric acid, 730ml of water and 195g of zinc powder to the reaction solution, keep the temperature at 18°C ​​until the reaction is complete, the reaction solution turns off-white, then add 25% sodium hydroxide solution until the pH value of the reaction solution is 10 , kept at 5°C for 1.5 hours, crystals were precipitated, and 121g of crude 3-chlorophenylhydrazine was obtained by filtration.

[0037] ⑶ Purification

[0038] Dissolve 121g of crude 3-chlorophenylhydrazine in 2420g of water, heat to 60°C to dissolve it completely, then add an ...

Embodiment 3

[0042] A preparation method for 3-chlorophenylhydrazine sulfate, comprising the following steps:

[0043] ⑴ diazotization

[0044] Add 500g of 3-chloroaniline and 1500ml of 37% concentrated hydrochloric acid into a 10L three-necked flask, cool to 2°C with ice salt, add 857g of 35% sodium nitrite aqueous solution while stirring, and keep the temperature between 0 and 5°C for 1.5 hours.

[0045] ⑵ reduction

[0046] Add 730ml of 37% concentrated hydrochloric acid, 730ml of water and 480g of zinc powder to the reaction solution, keep the temperature at 18°C ​​until the reaction is complete, the reaction solution turns off-white, then add 30% sodium hydroxide solution until the pH value of the reaction solution is 10 , kept at 5°C for 2 hours, crystals were precipitated, and 292g of crude 3-chlorophenylhydrazine was obtained by filtration.

[0047] ⑶ Purification

[0048] Dissolve 292g of crude 3-chlorophenylhydrazine in 5840g of water, heat it to 60°C to dissolve it completely...

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Abstract

The invention relates to a method for preparing 3-chlorophenylhydrazine sulfate. The method includes the steps of diazotization, reduction, purification and salt formation. According to the steps of diazotization and reduction, concentrated hydrochloric acid is adopted for keeping reaction liquid to be strongly acidic, and it is guaranteed that reacting can be conducted smoothly and completely. According to the step of reduction, zinc powder and concentrated hydrochloric acid are used as reducing agents to replace sodium thiosulfate, sodium hydrogen sulfite, stannous chloride-hydrochloric acid and the like, so that the reducing property is good, the yield is high, reaction time is shortened, impurities such as zinc hydroxide generated after reacting can be removed conveniently, the quantity of the impurities of the product is small, and the purity is high. According to the step of salt formation, acetone is used for drip washing, so that the purity of the product is improved, and meanwhile the appearance of the product is guaranteed. The preparation method is stable and reliable in technology and easy to operate, the product purity (the content is larger than or equal to 99.1% through high performance liquid chromatography detection) is high, the yield is larger than or equal to 42%, and the requirement for the 3-chlorophenylhydrazine sulfate on the market can be met completely.

Description

technical field [0001] The invention relates to the technical field of preparation of organic compounds, in particular to a preparation method of 3-chlorophenylhydrazine sulfate. Background technique [0002] As an important intermediate in organic synthesis, 3-chlorophenylhydrazine sulfate is widely used in the dye and pharmaceutical manufacturing industries, and has a broad market prospect. And the prepared product of existing 3-chlorophenylhydrazine sulfate has high impurity content, low purity, poor stability and small output, which cannot meet the needs of the market. Contents of the invention [0003] The purpose of the invention is to overcome the deficiencies in the prior art, and provide a kind of preparation method of 3-chlorophenylhydrazine sulfate with high purity, large output and good stability. [0004] In order to achieve the above object, the present invention adopts the following technical solutions: [0005] A preparation method of 3-chlorophenylhydraz...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C241/02C07C243/22
Inventor 何金
Owner TIANJIN CHEM REAGENT RES INST
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