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Method for preparing 3-aminophthalic acid

A technology of aminophthalic acid and nitrophthalic acid, which is applied in the preparation of organic compounds, chemical instruments and methods, and the preparation of cyanide reactions, etc., which can solve the problems of large environmental pollution, high cost, and high risk , to achieve the effect of good product purity, low production cost and low environmental pollution

Inactive Publication Date: 2017-07-28
CHANGZHOU PHARMA FACTORY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

There are few literature reports on the preparation method of this product, and there are reports on palladium-carbon catalytic hydrogenation reduction, but the raw material is converted into a sodium salt form, and the solvent used is an organic solvent (such as: ethanol), which is dangerous, requires many process operations, and is expensive.
There are reports of using hydrazine hydrate for reduction. Using hydrazine hydrate as a reducing agent is dangerous, unfavorable for industrial production, and the cost is relatively high
Also have the report that adopts iron powder reduction to prepare - aminophthalic acid in addition, its environmental pollution is big, and yield is low

Method used

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  • Method for preparing 3-aminophthalic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] (1) Add 65g of purified water to a 200mL beaker, add 3.79g of NaOH and stir to dissolve, cool to room temperature (25-35°C), add 3-nitrophthalic acid (10g), stir to dissolve;

[0015] (2) Add the above 3-nitrophthalic acid solution into a 2L hydrogenation kettle, add 0.5g of palladium carbon, start stirring, replace the air with nitrogen, and then replace the nitrogen with hydrogen, and keep the hydrogen pressure at 0.7-0.9Mpa, Keep the temperature of the reaction solution at 55-65°C for hydrogenation. The reaction takes about 12h;

[0016] (3) After the reaction is over, replace the hydrogen with nitrogen, and filter out the palladium carbon;

[0017] (4) Pour the filtrate into a 2L flask, lower the temperature to -5-0°C, add about 18.8mL of concentrated hydrochloric acid dropwise, keep the temperature at -5-5°C, and drop it for about 30 minutes. After the dropwise addition, keep stirring for 0.5 h;

[0018] (5) Suction filter and rinse twice with ethyl acetate. Th...

Embodiment 2

[0020] (1) Add 65kg of purified water to a 200L enamel kettle, add 3.79kg of NaOH and stir to dissolve, cool to room temperature (25-35°C), add 3-nitrophthalic acid (10kg), stir and dissolve, then transfer to turnover in the barrel;

[0021] (2) Take about 20L of the above solution, disperse palladium carbon (dry weight 0.5kg) in it, pump it into a 200L hydrogenation kettle by vacuum, and then pump the remaining 3-nitrophthalic acid solution into a 200L hydrogenation kettle by vacuum In the kettle, start stirring, replace the air with nitrogen, and then replace the nitrogen with hydrogen, keep the hydrogen pressure at 0.7-0.9Mpa, and keep the temperature of the reaction solution at 55-65°C for hydrogenation. The reaction takes about 12h;

[0022] (3) After the reaction is over, replace the hydrogen with nitrogen, remove the palladium carbon by filtering with a sand filter rod filter, filter again with a filter added with diatomaceous earth, and vacuum the filtrate into a 200L...

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Abstract

The invention discloses a method for preparing 3-aminophthalic acid by means of carrying out hydrogenation reduction on 3-nitrophthalic acid in aqueous solution. The method includes generating sodium salt solution under the effects of the 3-nitrophthalic acid and sodium hydroxide solution; carrying out reduction on nitro by the aid of hydrogen under catalytic effects of palladium on carbon to obtain amino. The hydrogen is used as a reducing agent. The method has the advantages that the 3-aminophthalic acid with the yield of 95% and the purity higher than 98% can be obtained by the aid of the method; the method can be implemented easily and feasibly and is low in production cost and little in environmental pollution, technological processes are short, and products are good in purity and high in yield.

Description

technical field [0001] The invention relates to a method for preparing 3-aminophthalic acid by hydrogenating and reducing 3-nitrophthalic acid in aqueous solution. Background technique [0002] 3-Aminophthalic acid has a wide range of uses and is an important intermediate in pharmaceuticals, pesticides, pigments, dyes and other industries. There are few literature reports on the preparation method of this product, and there are reports on palladium-carbon catalytic hydrogenation reduction, but the raw material is converted into a sodium salt form, and the solvent used is an organic solvent (such as: ethanol), which is dangerous, requires many process operations, and is expensive. . There are reports of using hydrazine hydrate for reduction. Using hydrazine hydrate as a reducing agent is dangerous, unfavorable for industrial production, and has a high cost. In addition, there is also a report on the preparation of aminophthalic acid by reduction of iron powder, but the envi...

Claims

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Application Information

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IPC IPC(8): C07C227/08C07C227/18C07C229/62
CPCC07C201/12C07C227/08C07C227/18C07C229/62C07C205/57
Inventor 狄聚财巫美金
Owner CHANGZHOU PHARMA FACTORY
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