Method for preparing o-phenylenediamine by catalytic hydrogenation of o-nitrophenylamine
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A technology of o-nitroaniline and o-phenylenediamine, which is applied in the field of preparing o-phenylenediamine by catalytic hydrogenation of o-nitroaniline, can solve the problems of many amine impurities and difficulties, and achieve short production cycle, low pollution, The effect of short reaction times
Inactive Publication Date: 2012-08-15
JIANGSU KANGHENG CHEM
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[0006] The direct ammoniation of o-dichlorobenzene to produce o-phenylenediamine has a lot of amine impurities, which makes subsequent refining difficult. If this industrialization problem can be solved, it will have a better application prospect in the future.
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example 1
[0026] 150g of o-nitroaniline and 300g of methanol were added to the autoclave, and 7.5g of self-made 200 mesh Ni catalyst was added at the same time, the autoclave was closed, the hydrogen valve was opened, hydrogen gas was introduced into the autoclave, and the pressure of the autoclave was adjusted for 3 times. 2.0 MPa, stir and heat up to 60-70°C to react, so that the pressure does not change (about 2-3h), take a sample, and the result of gas chromatography analysis shows that the content of o-phenylenediamine is 98.50%.
example 2
[0028] Add 500 g of o-nitroaniline and 1000 g of methanol into the autoclave, and at the same time add 25 g of self-made Ni catalyst, close the autoclave, open the hydrogen valve, feed hydrogen into the autoclave, ventilate 3 times, and adjust the pressure of the autoclave to 2.0 MPa , stir and heat up to 60-70°C to react, so that the pressure does not change (about 2-3h), take a sample, and the gas chromatography analysis results show that the content of o-phenylenediamine is 98.78%. After the reaction solution is filtered, the solvent is recovered, and then rectified to obtain a white o-phenylenediamine 360g of phenylenediamine, GC detection 99.9%, yield 92.0%.
example 3
[0030] Add 2000 g of o-nitroaniline and 4000 g of methanol into the autoclave, and at the same time add 25 g of self-made Ni catalyst, close the autoclave, open the hydrogen valve, feed hydrogen into the autoclave, ventilate 3 times, and adjust the pressure of the autoclave to 2.0 MPa , stir and heat up to 60-70°C for reaction, so that the pressure does not change (about 2-3h), sampling, and the result of gas chromatography analysis shows that the content of o-phenylenediamine is 99.00%. After the reaction solution is filtered, the solvent is recovered, and then rectified to obtain a white o-phenylenediamine 1455g of phenylenediamine, GC detection 99.9%, yield 92.95%.
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Abstract
The invention discloses a method for preparing o-phenylenediamine by catalytic hydrogenation of o-nitrophenylamine. The method is characterized in that: in the hydrogenation reaction of o-nitrophenylamine, alcohol is used as a solvent, nickel is used as a catalyst, reduction reaction is performed for 2 to 10 hours under the hydrogen pressure of 1.0 to 6 MPa at the temperature of between 40 and 80 DEG C, and the reaction product is rectified to form the while o-phenylenediamine. The method has the advantages that the alcohol is used as the solvent in the catalytic hydrogenation for producing o-phenylenediamine, the alcohol can be reclaimed and directly used for next reaction, and the waste residue produced by distillation can be used as an organic fuel, so that the problem that a large amount of waste water containing organic substances is produced in reduction of iron powder or sodium sulfide in the conventional process is solved; and thick acid and thick alkali used in the conventional process are avoided in the hydrogenation process, so that corrosion of equipment is greatly reduced, pollution is reduced, and almost zero pollution is realized. In addition, compared with the conventional iron powder or sodium sulfide reduction, the catalytic hydrogenation process has the advantages of low pollution, high yield, high quality, short production period and low energy consumption.
Description
technical field [0001] The invention relates to a method for preparing o-phenylenediamine through catalytic hydrogenation of o-nitroaniline. Background technique [0002] O-phenylenediamine is an important intermediate of dyes, pesticides, additives, photosensitive materials, etc. Itself is the dye fur yellow brown M. Used in the manufacture of polyamide, polyurethane, fungicides carbendazim and thiophanate, vat red GG, leveling agent, anti-aging agent MB, also used in the preparation of developers, surfactants, etc. [0003] There are currently three possible routes: [0004] 1: Direct ammoniation of o-dichlorobenzene to produce o-phenylenediamine [0005] [0006] The direct ammoniation of o-dichlorobenzene to produce o-phenylenediamine has a lot of amine impurities, which makes subsequent refining difficult. If this industrialization problem can be solved, it will have a better application prospect in the future. [0007] 2: Preparation of o-phenylenediamine by red...
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