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Preparation method of 3-methyl phenylhydrazine sulfate

A technology of methylphenylhydrazine 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 output of products, and achieve the effects of improving purity, easy operation, and less impurities

Inactive Publication Date: 2018-03-20
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 3-methylphenylhydrazine sulfate 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

[0018] A preparation method of 3-methylphenylhydrazine sulfate, comprising the following steps:

[0019] ⑴Diazotization

[0020] Add 50g 3-methylaniline and 150ml 37% concentrated hydrochloric acid in a 1L three-necked flask, cool to 2°C with ice salt, add 85.7g of 35% aqueous sodium nitrite solution while stirring, and keep the temperature at 2°C to react for 1 hour.

[0021] ⑵Restore

[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 ​​to 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, The temperature was kept at 5°C for 1 hour, crystals were precipitated, and 26.4 g of crude 3-methylphenylhydrazine was obtained by filtration.

[0023] (3) Purification

[0024] Dissolve 26.4g of 3-methylphenylhydrazine crude product in 528g of water, heat to 60°C to diss...

Embodiment 2

[0028] A preparation method of 3-methylphenylhydrazine sulfate, comprising the following steps:

[0029] ⑴Diazotization

[0030] Add 200g of 3-methylaniline and 600ml of 37% concentrated hydrochloric acid in a 5L there-necked flask, cool to 2°C with ice salt, add 343g of 35% aqueous sodium nitrite solution while stirring, and keep the temperature at 2°C to react for 1.5 hours.

[0031] ⑵Restore

[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 becomes off-white, and then add 25% sodium hydroxide solution until the pH value of the reaction solution is 10 , 5 °C for 1.5 hours, crystals were precipitated, and 121g of crude 3-methylphenylhydrazine was obtained by filtration.

[0033] (3) Purification

[0034] Dissolve 121g of crude 3-methylphenylhydrazine in 2420g of water, heat it to 60°C to dissolve it completely, add an...

Embodiment 3

[0038] A preparation method of 3-methylphenylhydrazine sulfate, comprising the following steps:

[0039] ⑴Diazotization

[0040] In the there-necked flask of 10L, add 500g 3-methylaniline and 1500ml 37% concentrated hydrochloric acid, cool to 2 ℃ with ice salt, add 857g of 35% aqueous sodium nitrite solution while stirring, keep the temperature at 0~5 ℃ and react 1.5 Hour.

[0041] ⑵Restore

[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 becomes off-white, and 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-methylphenylhydrazine was obtained by filtration.

[0043] (3) Purification

[0044] Dissolve 292g of crude 3-methylphenylhydrazine in 5840g of water, heat to 60°C to make it completely dissolved, a...

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Abstract

The invention relates to a preparation method of 3-methylphenylhydrazine sulfate, comprising the steps of diazotization, reduction, purification and salt formation. In the steps of diazotization and reduction, concentrated hydrochloric acid is used to keep the reaction solution in strong acidity, so as to ensure the smooth and complete progress of the reaction. In the reduction step, zinc powder-concentrated hydrochloric acid is used as the reducing agent instead of sodium thiosulfate, sodium bisulfite, stannous chloride-hydrochloric acid, etc., which not only has good reduction performance, high yield, shortens the reaction time, and generates Impurities such as zinc hydroxide are easy to remove, so that the product has less impurities and high purity. Washing with acetone in the salt-forming step not only improves the purity of the product, but also ensures the appearance of the product. The preparation method has stable and reliable process, easy operation, high product purity (the content measured by high-performance liquid chromatography is more than 99.1%), and the yield is more than 42%, which fully meets the needs of the market for 3-methylphenylhydrazine sulfate.

Description

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

Claims

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Application Information

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IPC IPC(8): C07C241/02C07C243/22
CPCC07C241/02C07C245/20C07C243/22
Inventor 申倩
Owner TIANJIN CHEM REAGENT RES INST
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