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Method for preparing 3-amino-2-methyl benzoic acid

A technology of methyl benzoic acid and amino, which is applied in chemical instruments and methods, cyanide reaction preparation, organic compound preparation, etc., can solve the problems of high environmental risk, low conversion rate, environmental pollution, etc., and achieve environmental friendliness, treatment Simple process and wide range of effects

Inactive Publication Date: 2014-10-01
四川北方红光特种化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] For a long time, the iron powder reduction method was mostly used in the preparation of 3-amino-2-methylbenzoic acid. This method utilizes the reducibility of iron powder in an acidic solution environment to convert 3-nitro-2-methylbenzoic acid into 3- Amino-2-methylbenzoic acid, about 95% conversion rate, produces a large amount of poisonous iron sludge (3 tons / ton product) and waste water that contain aromatic amine in the conversion process, can cause serious environmental pollution problem, also needs during aftertreatment After decolorization and other refining processes, the cost is relatively high
[0003] As an improvement, the alkali sulfide reduction method is adopted. In this method, alkali sulfide (such as sodium sulfide) and sulfur are configured into a solution of a certain concentration in a certain proportion, and 3-nitro-2-methylbenzoic acid is added. This method converts The conversion rate is 76-80%, the conversion rate is low, there is sulfite in the wastewater, and the environmental risk is large

Method used

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  • Method for preparing 3-amino-2-methyl benzoic acid
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  • Method for preparing 3-amino-2-methyl benzoic acid

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experiment example

[0018] 1. Catalyst selection

[0019] Using Raney nickel catalyst, diatom ooze-supported nickel catalyst, and 6504k nickel catalyst respectively, the hydrogenation test was carried out according to the operation procedure of step (2) in Example 2, and the test data are shown in Table 1.

[0020] Table 1 Hydrogenation data table of different catalysts

[0021]

[0022] From the above data, it can be seen that it is feasible to use Raney nickel catalyst, diatom mud-supported nickel catalyst, and 6504K nickel catalyst for liquid phase hydrogenation of 3-nitro-2-methylbenzoic acid. From the perspective of hydrogen absorption speed, the absorption rate of 6504K nickel catalyst Hydrogen has the fastest speed. From the perspective of reaction time, the total reaction time of diatom ooze-supported nickel catalyst and 6504K nickel catalyst is equivalent, and the reaction time of Raney nickel catalyst is relatively long. On the whole, it is relatively better to use 6504K nickel cata...

Embodiment 1

[0034] Embodiment 1 prepares the method for 3-amino-2-methylbenzoic acid

[0035] The method for preparing 3-amino-2-methylbenzoic acid comprises the following steps:

[0036] 1) Salt-forming reaction:

[0037]

[0038] The catalyst is 6504K nickel, pure water is used as the solvent in the liquid phase, and the solvent ratio is 2.5:1, the hydrogenation reaction pressure is controlled at 2.0 MPa, and the temperature is 125°C.

[0039] 3) Adjust the reducing solution obtained in step 2) to pH=5.4 with hydrochloric acid to obtain the product with a yield of over 95%.

Embodiment 2

[0040] Embodiment 2 prepares the method for 3-amino-2-methylbenzoic acid

[0041] (1) Raw material into salt

[0042] Weigh 1000g of 3-nitro-2-methylbenzoic acid, add 2000g of distilled water, stir evenly, add caustic soda (mass percentage content 99%) under stirring, adjust pH=7~8, now the solution is clear, wait for use.

[0043] (2) Hydrogenation reduction

[0044] In a 2L autoclave, add 500ml of distilled water, 10g of 6504K nickel catalyst (nickel catalyst supported by carbon powder, manufactured by Luina, Germany), control the pressure at 1.0MPa, raise the temperature to 100°C, and activate for 1h. After activation, draw out the distilled water, add 480g of 3-nitro-2-methylbenzoic acid sodium solution at 80°C, that is, 150g of 3-nitro-2-methylbenzoic acid raw material, seal the autoclave, replace it with nitrogen for 3 times, and then use hydrogen Replace 3 times, open the hydrogen inlet valve, control the pressure at 2.0MPa, start stirring to 1000n / min, raise the tem...

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Abstract

The invention discloses a method for preparing 3-amino-2-methyl benzoic acid. The method comprises the following steps: by using 3-nitryl-2-methyl benzoic acid as a raw material, salifying; and carrying out liquid phase catalytic hydrogenation to prepare the 3-amino-2-methyl benzoic acid. The method for preparing 3-amino-2-methyl benzoic acid provided by the invention is environmentally friendly and wide in application range, and many different solvents can be selected as liquid phases. The method is simple in post-treatment process and free from purification and is just filtered and dried after acidification. The product purity can reach over 99% and the yield is high (over 95%).

Description

technical field [0001] The invention relates to the field of organic preparation, in particular to a method for preparing 3-amino-2-methylbenzoic acid. Background technique [0002] For a long time, the iron powder reduction method was mostly used in the preparation of 3-amino-2-methylbenzoic acid. This method utilizes the reducibility of iron powder in an acidic solution environment to convert 3-nitro-2-methylbenzoic acid into 3- Amino-2-methylbenzoic acid, about 95% conversion rate, produces a large amount of poisonous iron sludge (3 tons / ton product) and waste water that contain aromatic amine in the conversion process, can cause serious environmental pollution problem, also needs during aftertreatment After refining processes such as decolorization, the cost is relatively high. [0003] As an improvement, the alkali sulfide reduction method is adopted. In this method, alkali sulfide (such as sodium sulfide) and sulfur are configured into a solution of a certain concentr...

Claims

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Application Information

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IPC IPC(8): C07C229/60C07C227/04C07C227/18
Inventor 刘晓燕刘传刚姜能贺龙海向勇蒲祖伦杜成平李永红
Owner 四川北方红光特种化工有限公司
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