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4-bromophenylhydrazine phosphate preparation method

A technology of bromophenylhydrazine phosphate and bromophenylhydrazine, which is applied in the field of preparation of 4-bromophenylhydrazine phosphate, can solve the problems of high impurity content, poor stability, and small output of products, and achieves improved purity, easy operation, and improved impurities. less effect

Inactive Publication Date: 2016-01-27
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 obtained by the preparation method of existing 4-bromophenylhydrazine phosphate has high impurity content, low purity, poor stability, and small output, which cannot meet the needs of the market

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A preparation method for 4-bromophenylhydrazine phosphate, comprising the following steps:

[0023] ⑴ diazotization

[0024] Add 50g of 4-bromoaniline and 150ml of 37% concentrated hydrochloric acid into a 1L three-necked flask, cool to 2°C with ice salt, add 65g 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 25.6 g of crude 4-bromophenylhydrazine was obtained by filtration.

[0027] ⑶ Purification

[0028] Dissolve 25.6g of crude 4-bromophenylhydrazine in 514g of water, heat it to 60°C to dissolve it ...

Embodiment 2

[0032] A preparation method for 4-bromophenylhydrazine phosphate, comprising the following steps:

[0033] ⑴ diazotization

[0034] Add 200g of 4-bromoaniline and 600ml of 37% concentrated hydrochloric acid into a 5L three-necked flask, cool to 2°C with ice salt, add 270g 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 118g of crude 4-bromophenylhydrazine was obtained by filtration.

[0037] ⑶ Purification

[0038] Dissolve 118g of crude 4-bromophenylhydrazine in 2380g of water, heat to 60°C to dissolve it completely, then add an ap...

Embodiment 3

[0042] A preparation method for 4-bromophenylhydrazine phosphate, comprising the following steps:

[0043] ⑴ diazotization

[0044] Add 500g of 4-bromoaniline and 1500ml of 37% concentrated hydrochloric acid into a 10L three-necked flask, cool to 2°C with ice salt, add 650g of 35% sodium nitrite aqueous solution while stirring, and keep the temperature at 2°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 272g of crude 4-bromophenylhydrazine was obtained by filtration.

[0047] ⑶ Purification

[0048] Dissolve 272g of crude 4-bromophenylhydrazine in 5420g of water, heat to 60°C to dissolve it completely, then add an ap...

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Abstract

The invention relates to a 4-bromophenylhydrazine phosphate preparation method. The method comprises the steps of diazotization, reduction, purification and salt formation. In the diazotization and reduction steps, a reaction liquid is kept strongly acidic with concentrated hydrochloric acid, such that smooth and complete reactions are ensured. In the reduction step, zinc powder-concentrated hydrochloric acid is adopted as a reducing agent for replacing sodium thiosulfate, sodium bisulfite, stannous chloride-hydrochloric acid and the like, such that reduction performance is good, yield is high, and reaction time is shortened. Impurities such as zinc hydroxide produced in the reaction are easy to remove, such that product impurity amount is low, and product purity is high. In the salt formation step, acetone is used for leaching, such that product purity is improved, and product appearance is ensured. The preparation method has the advantages of stable and reliable process, easy operation, and high product purity (product content is no lower than 99.2% as a result of high-performance liquid chromatography). A product yield is no lower than 42%. The method can completely satisfy market demands on 4-bromophenylhydrazine phosphate.

Description

technical field [0001] The invention relates to the technical field of preparation of organic compounds, in particular to a preparation method of 4-bromophenylhydrazine phosphate. Background technique [0002] As an important organic synthesis intermediate, 4-bromophenylhydrazine phosphate is widely used in the pharmaceutical manufacturing industry and has a broad market prospect. However, the product obtained by the existing 4-bromophenylhydrazine phosphate preparation method 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 method for preparing 4-bromophenylhydrazine phosphate 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 kind of preparation method of 4-br...

Claims

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Application Information

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IPC IPC(8): C07C241/02C07C243/22
Inventor 何金
Owner TIANJIN CHEM REAGENT RES INST
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