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Preparation method of 4-bromo-2-aminophenol

A technology of aminophenol and bromophenol, applied in the field of preparation of 4-bromo-2-aminophenol, can solve problems such as low selectivity and low conversion rate, achieve low debromination rate, high conversion rate, and inhibit debromination side effects. effect of reaction

Active Publication Date: 2020-06-19
SINOPHARM CHEM REAGENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the defects of low conversion rate and low selectivity in the preparation of 4-bromo-2-aminophenol in the prior art, the present invention provides a method for preparing 4-bromo-2-aminophenol

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] A preparation method of 4-bromo-2-aminophenol, comprising the steps of:

[0026] (1) Raney-Ni catalyst 5.0g is added in water, then ferric nitrate and chromium nitrate are added, stirred and mixed uniformly to obtain a mixed solution;

[0027] Based on nickel moles, the addition of the iron nitrate is 0.023mol, and the addition of the chromium nitrate is 0.015mol;

[0028] (2) adding mass concentration to the mixed solution obtained in step (1) is 5wt% sodium hydroxide solution, adjusting the pH of the mixed solution to be 8 ± 0.5, continuing to stir and reacting for 30min, washing with water to neutrality, replacing water with methanol , obtain Fe-Cr modified Raney-Ni catalyst;

[0029] (3) Dissolve 1mol of 2-nitro-4-bromophenol in 500mL of methanol, add 0.8mol% of the Fe-Cr modified Raney-Ni catalyst obtained in step (2), and under normal pressure, feed hydrogen to carry out hydrogenation Reaction, after detecting the disappearance of the reaction of the central con...

Embodiment 2

[0033] A preparation method of 4-bromo-2-aminophenol, comprising the steps of:

[0034] (1) Raney-Ni catalyst 5.0g is added in water, then ferric nitrate and chromium nitrate are added, stirred and mixed uniformly to obtain a mixed solution;

[0035] Based on nickel moles, the addition of the iron nitrate is 0.025mol, and the addition of the chromium nitrate is 0.012mol;

[0036] (2) adding mass concentration to the mixed solution obtained in step (1) is 10wt% sodium hydroxide solution, adjusting the pH of the mixed solution to be 8 ± 0.5, continuing to stir and reacting for 30min, washing with water to neutrality, replacing water with methanol , obtain Fe-Cr modified Raney-Ni catalyst;

[0037] (3) Dissolve 1mol of 2-nitro-4-bromophenol in 500mL of methanol, add 1.0mol% of the Fe-Cr modified Raney-Ni catalyst obtained in step (2), and under normal pressure, feed hydrogen to carry out hydrogenation Reaction, after detecting the disappearance of the reaction of the central co...

Embodiment 3

[0041] A preparation method of 4-bromo-2-aminophenol, comprising the steps of:

[0042] (1) Raney-Ni catalyst 5.0g is added in water, then ferric nitrate and chromium nitrate are added, stirred and mixed uniformly to obtain a mixed solution;

[0043] Based on nickel moles, the addition of the iron nitrate is 0.027mol, and the addition of the chromium nitrate is 0.018mol;

[0044] (2) adding mass concentration to the mixed solution obtained in step (1) is 5wt% sodium hydroxide solution, adjusting the pH of the mixed solution to be 8 ± 0.5, continuing to stir and reacting for 30min, washing with water to neutrality, replacing water with methanol , obtain Fe-Cr modified Raney-Ni catalyst;

[0045] (3) Dissolve 1 mol of 2-nitro-4-bromophenol in 500 mL of methanol, add 1.2 mol% of the Fe-Cr modified Raney-Ni catalyst obtained in step (2), and under normal pressure, feed hydrogen to carry out hydrogenation Reaction, after detecting the disappearance of the reaction of the central ...

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Abstract

The invention belongs to the field of chemical synthesis, and particularly relates to a preparation method of 4-bromo-2-aminophenol. The method comprises the following steps: (1) adding a Raney-Ni catalyst into water, adding ferric nitrate and chromium nitrate, and stirring to obtain a mixed solution; (2) adding an alkaline solution into the mixed solution obtained in the step (1), continuously stirring, washing with water, and replacing water with methanol to obtain an Fe-Cr modified Raney-Ni catalyst; (3) dissolving 2-nitro-4-bromophenol in an alcohol solvent, adding the Fe-Cr modified Raney-Ni catalyst, and carrying out a hydrogenation reaction at normal pressure to obtain an alcohol solution of 4-bromo-2-aminophenol; and (4) filtering, desolventizing and refining to obtain the 4-bromo-2-aminophenol. According to the invention, the Fe-Cr modified Raney-Ni catalyst provided by the invention has the advantages of high conversion rate, good selectivity, capability of inhibiting debromination side reaction, low debromination rate and good durability.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a preparation method of 4-bromo-2-aminophenol. Background technique [0002] 4-Bromo-2-aminophenol is an important intermediate in the production of dyes, mainly used in the production of medicines, dyes and chemicals. In the prior art, most aromatic amines are obtained by reduction of nitroaromatics, among which iron powder reduction method is more common, but the post-treatment process of iron powder reduction method is relatively complicated, with high energy consumption and serious pollution. Catalytic hydrogenation is a green reduction technology, which is being used more and more. Among them, the Raney-Ni catalyst has the advantages of high activity and good sedimentation separation performance for the hydrogenation reaction of 4-bromo-2-aminophenol, but its own There are also many disadvantages. Direct use of commercial Raney-Ni catalysts for reductive hydro...

Claims

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Application Information

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IPC IPC(8): C07C213/02C07C215/76B01J25/02B01J23/86
CPCC07C213/02C07C215/76B01J25/02B01J23/862B01J23/002
Inventor 顾小焱吴孝兰郭建国吕文华
Owner SINOPHARM CHEM REAGENT
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