Preparation of o-aminophenol by liquid phase hydrogenation

O-aminophenol (OAP) is an important chemical intermediate widely used in dyes, medicine, printing and biological fields. Its traditional synthesis method is to use o-nitrochlorobenzene as raw material, which is hydrolyzed and reduced to iron powder. The three wastes are seriously polluted during the reduction process, and the product is wrapped in iron sludge, so that the product yield is not high. The liquid phase hydrogenation method and the use of mixed solvent not only overcome the serious problem of three wastes pollution, but also improve the yield.
Using alcohol-water as the medium, o-nitrophenol was catalyzed by hydrogenation to produce o-aminophenol. The alcohol-to-water volume ratio is 2:1.
Pd/C and Raeneni nickel were used as catalysts for catalytic hydrogenation reaction, the dosage was 3% of the weight of nitro, and it still had high activity after more than five applications.
Under the optimized conditions, o-nitrophenol liquid phase catalytic hydrogenation to produce o-aminophenol products with a purity of more than 98%, and the yield was close to 80%.



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