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Method for producing 3-methyl-4-aminobenzoic acid through catalytic hydrogenation method

A technology of aminobenzoic acid and nitrobenzoic acid, which is applied in chemical instruments and methods, preparation of organic compounds, physical/chemical process catalysts, etc., can solve problems such as iron mud environmental pollution, poor working conditions, and time to wait. Achieve the effect of reducing environmental pressure, low cost and good product quality

Inactive Publication Date: 2017-08-01
济南和润化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The production of 3-methyl-4-aminobenzoic acid by iron powder reduction method is relatively low in cost and mature in production, but the working conditions are poor and the environmental pollution caused by iron sludge is serious, so it is generally not used.
Indian scholar Gowda used hydrazine formate as a reducing agent and also achieved success with iron powder reduction, but so far it has only been tested in the laboratory, and it will take time to further apply it in large-scale industrial production

Method used

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  • Method for producing 3-methyl-4-aminobenzoic acid through catalytic hydrogenation method

Examples

Experimental program
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Effect test

Embodiment 1

[0017] Taking 200 kg of 3-methyl-4-nitrobenzoic acid as an example, the catalyst used is a self-made catalyst. The total amount of catalyst used in the production process is 0.1-3% (0.2-6 kg) of the raw material, and the total amount of water is the raw material 8 times (1600 kg), before hydrogenation, 3-methyl-4-nitrobenzoic acid, water and catalyst are put into the tank in the following order.

[0018] 1. Put 200 kg of 3-methyl-4-nitrobenzoic acid and 1600 kg of water into the reaction kettle, and adjust the pH value of the reaction solution to 7-8 by adding sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate, etc. , gas displacement.

[0019] 2. Introduce hydrogen to start the hydrogenation reaction, control the reaction temperature to 80±5°C, and control the reaction pressure to 0.3-1.0Mpa.

[0020] 3. After the reaction is finished, filter the catalyst, and add acidifying agents such as hydrochloric acid and sulfuric acid to the filtrate to adj...

Embodiment 2

[0023] Taking 200 kg of 3-methyl-4-nitrobenzoic acid to produce 3-methyl-4-aminobenzoic acid as an example, the catalyst used in the production process is a noble metal catalyst (self-made), and the dosage is 3-methyl-4-nitrobenzoic acid 0.1-3% (0.2-6 kg) of benzoic acid, and the total amount of water is 8 times (1600 kg) of the raw material. In continuous production, 3-methyl-4-nitrobenzoic acid, water and catalyst are based on (1) was added in order. In order to investigate the stability of the process, five consecutive experiments were carried out, and the results are shown in Table 1 as follows:

[0024]

[0025] Reaction conditions: temperature 80±5°C, pressure 0.3-1.0Mpa, ph7-8.

[0026] As can be seen from the table, the conversion rate of 3-methyl-4-nitrobenzoic acid is 100%, the selectivity of 3-methyl-4-aminobenzoic acid is more than 99.5%, and the finished product content is more than 99.7%. Above 97%.

Embodiment 3

[0028] Taking 200 kilograms of 3-methyl-4-nitrobenzoic acid to produce 3-methyl-4-aminobenzoic acid as an example, the catalyst used in the production process is a noble metal catalyst, and the dosage is 3-methyl-4-nitrobenzoic acid 0.1-3% (0.2-6 kg), the total amount of water is 8 times (1600 kg) of the raw material, during continuous production, the reaction is carried out according to the production process of Example 1, the difference is that the catalyst is recycled. After the reaction in each kettle is completed, after the catalyst is filtered by pressure, the catalyst is blown back into the reaction kettle, and 0.1-0.5 kg of catalyst is added, and the catalyst is recycled. After the catalyst started to be used mechanically, the amount of new catalyst added was greatly reduced, only 5%-25% of the original, which greatly reduced the cost. After mass production experiments, this catalyst can be used continuously for more than ten times.

[0029] In order to reduce the amou...

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Abstract

The invention discloses a method for producing 3-methyl-4-aminobenzoic acid through a catalytic hydrogenation method. According to the method, 3-methyl-4-nitrobenzoic acid is dissolved in an aqueous solution, the obtained solution is added in a hydrogenation kettle, a catalyst is added, hydrogen is led in, a hydrogenation reaction is carried out, and acidification, crystallization, and drying are carried out to obtain 3-methyl-4-aminobenzoic acid. The raw material conversion rate is 100%, and the obtained product is white powder, has the chromatogram purity no less than 99%, and has the yield no less than 95%.

Description

technical field [0001] The invention relates to a method for producing organic acid, in particular to a method for producing 3-methyl-4-aminobenzoic acid by catalytic hydrogenation. Background technique [0002] 3-Methyl-4-aminobenzoic acid is an important class of dyes and pharmaceutical intermediates, using it as a raw material, many downstream products with high added value can be developed. A series of yellow reactive dyes derived from it can be used as deep yellow dyes or as yellow components in black dyes, and are currently in great demand in the market. 3-methyl-4-aminobenzoic acid is generally obtained from 3-methyl-4-nitrobenzoic acid through reduction reaction. In the literature, there are three ways to prepare 3-methyl-4-aminobenzoic acid by reduction of 3-methyl-4-nitrobenzoic acid: iron powder reduction, hydrazine reduction and hydrogenation reduction. The production of 3-methyl-4-aminobenzoic acid by iron powder reduction method is relatively low in cost and ...

Claims

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Application Information

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IPC IPC(8): C07C227/04C07C229/60B01J23/38
CPCC07C227/04B01J23/38C07C229/60
Inventor 侯卫波唐国武韩龙凯王超李娟王光
Owner 济南和润化工科技有限公司
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