Process for preparing ortho-aminophenol by virtue of continuous catalytic hydrogenation

Abstract

The invention discloses a process for preparing ortho-aminophenol by virtue of continuous catalytic hydrogenation, and the process is implemented by taking o-nitrophenol as a raw material through carrying out a continuous catalytic hydrogenation reaction in a fixed bed reactor by using a Pd/Al2O3 catalyst, and then separating and purifying the obtained product so as to obtain a target product ortho-aminophenol. The process disclosed by the invention can be used for realizing a continuous catalytic hydrogenation reaction, and is short in technological process, high in degree of automation, low in labor strength, less in equipment investment, and large in production capacity; the Pd/Al2O3 catalyst is good in selectivity and high in activity, and can be used for improving the yield and purity of products, the yield reaches up to 97%, and the purity reaches up to over 99%; no material is discharged and spills over in the whole reaction process, so that the consumption is minimized, therefore, the process is beneficial to resource conservation and environmental conservation, and has good economic and social benefits; both the labor intensity of workers is reduced, and the whole site environment is clean and tidy, so that the intrinsic competitiveness and extrinsic appearance of products are promoted, and therefore, the process is suitable for being widely applied to industrial production.

Description

technical field [0001] The invention relates to a preparation process of o-aminophenol, in particular to a method using a supported catalyst Pd / Al 2 o 3 Process for preparing o-aminophenol by continuous catalytic hydrogenation. Background technique [0002] At present, Raney nickel is used as a catalyst in the industrial production of o-aminophenol to carry out batch-type hydrogenation reduction reaction to obtain o-aminophenol products. However, Raney nickel has its own shortcomings as a catalyst. The conditions for Raney nickel to act are relatively harsh, and it can only exert higher catalytic activity in an alkaline reaction system, which requires a high pH value of the solution. Otherwise, the catalyst activity will decrease. Soon, the proper catalytic effect will not be achieved, resulting in high catalyst consumption; at the same time, during the reaction process, side reactions will increase, a certain amount of solid by-products will be produced, and a large amoun...

AI Technical Summary

Problems solved by technology

[0003] Aiming at the deficiencies of the prior art, the present invention provides a process for preparing o-aminophenol by continuous catalytic hydrogenation, which solves the problems of cumbersome operation, heavy labor, harsh reaction conditions, and low yield of the batch hydrogenation reduction reaction process in the prior art. Low, poor product quality, and a large amount of waste water, difficult to handle, serious environmental pollution and other issues

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