Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Preparation method of 3-bromohydrazinobenzene hydrochloride

A technology of bromophenylhydrazine hydrochloride and bromophenylhydrazine, which is applied in the field of preparation of 3-bromophenylhydrazine hydrochloride, can solve the problems of high impurity content, poor stability, small output and the like in the product, and achieves improved purity and easy operation. , the effect of less impurities

Inactive Publication Date: 2013-11-20
TIANJIN CHEM REAGENT RES INST
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

And the product obtained by the preparation method of existing 3-bromophenylhydrazine hydrochloride has high impurity content, low purity, poor stability, and small output, which cannot meet the needs of the market

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A preparation method for 3-bromophenylhydrazine hydrochloride, comprising the following steps:

[0019] ⑴ diazotization

[0020] Add 50g of 3-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.

[0021] ⑵ reduction

[0022] Add 450ml of 37% concentrated hydrochloric acid, 450ml of water and 120g 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 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 24 g of crude 3-bromophenylhydrazine was obtained by filtration.

[0023] ⑶ Purification

[0024] Dissolve 24g of crude 3-bromophenylhydrazine in 480g of water, heat to 60°C to dissolve it completely, the...

Embodiment 2

[0028] A preparation method for 3-bromophenylhydrazine hydrochloride, comprising the following steps:

[0029] ⑴ diazotization

[0030] Add 200g of 3-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.

[0031] ⑵ reduction

[0032] 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 115g of crude 3-bromophenylhydrazine was obtained by filtration.

[0033] ⑶ Purification

[0034] Dissolve 115g of crude 3-bromophenylhydrazine in 2300g of water, heat to 60°C to dissolve it completely, then add a...

Embodiment 3

[0038] A preparation method for 3-bromophenylhydrazine hydrochloride, comprising the following steps:

[0039] ⑴ diazotization

[0040] Add 500g of 3-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.

[0041] ⑵ reduction

[0042] 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 269g of crude 3-bromophenylhydrazine was obtained by filtration.

[0043] ⑶ Purification

[0044] Dissolve 269g of crude 3-bromophenylhydrazine in 5380g of water, heat to 60°C to dissolve it completely, add an app...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention relates to a preparation method of 3-bromohydrazinobenzene hydrochloride, which comprises the steps of diazotization, reduction, purification and salification. In the diazotization and reduction steps, concentrated hydrochloric acid is adopted to keep the reaction solution strongly acidic, thereby ensuring the smooth performance of the reaction. In the reduction step, the zinc powder-concentrated hydrochloric acid is used as the reducer instead of sodium thiosulfate, sodium bisulfite, stannous chloride-hydrochloric acid or the like, and thus, has the advantages of favorable reducibility, high yield and shorter reaction time; and zinc hydroxide and other impurities generated in the reaction are convenient to remove, and thus, the product has fewer impurities and higher purity. In the salification step, acetone is used for rinsing, thereby enhancing the purity of the product and ensuring the appearance of the product. The preparation method is stable and reliable in technique and easy to operate; the product purity is high (the content by high performance liquid chromatography is at least 99%), and the yield is at least 38%; and thus, the invention completely satisfies the demands of the market for 3-bromohydrazinobenzene hydrochloride.

Description

technical field [0001] The invention relates to the technical field of preparation of organic compounds, in particular to a preparation method of 3-bromophenylhydrazine hydrochloride. Background technique [0002] As an important organic synthesis intermediate, 3-bromophenylhydrazine hydrochloride is widely used in the pharmaceutical manufacturing industry and has a broad market prospect. And the product obtained by the preparation method of existing 3-bromophenylhydrazine hydrochloride 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 preparation method of 3-bromophenylhydrazine hydrochloride 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...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C07C243/22C07C241/02
Inventor 何金
Owner TIANJIN CHEM REAGENT RES INST
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com