Preparation process of 4-amino diphenylamine

Abstract

The invention relates to a method for preparing 4-aminodiphenylamine by a nitrobenzene method. It mainly solves the need to use precious metals in the catalyst in the past technology, which makes the catalyst preparation cost high; the main impurities produced in the process, azobenzene oxide / azobenzene and / or hydroazobenzene need to be recovered separately or only pure raw materials can be used question. In the present invention, condensation reaction occurs with aniline and nitrobenzene in the presence of water and alkali, and then the condensation liquid containing strong alkali or strong organic base is reacted with water and alkali in the presence of skeleton nickel, especially modified skeleton nickel catalyst. Aromatic amine is used as a solvent, and the technical scheme of hydrogenation reduction reaction to generate 4-aminodiphenylamine solves this problem well, and realizes nitro, nitroso, azo or / and oxidized diphenylamine in one step through hydrogenation reduction reaction. The reduction of nitrogen compounds can be used in the industrial production of 4-aminodiphenylamine.

Description

technical field [0001] The invention relates to a method for preparing 4-aminodiphenylamine, in particular to a method for preparing 4-aminodiphenylamine by a nitrobenzene method. Background technique [0002] 4-aminodiphenylamine (4-aminodiphenylamine), also known as p-aminodiphenylamine, N-phenyl-p-phenylenediamine or RT base, is mainly used in the production of p-phenylenediamine rubber antioxidants 4010NA, 4020, 4010 and 688, etc. . In addition, it can also be used in the synthesis of blue salt VRT for dyes, textiles, printing and pharmaceutical industries. [0003] There are more than ten kinds of production methods for 4-aminodiphenylamine, and the currently industrialized methods mainly include aniline method, formanilide method, diphenylamine method and nitrobenzene method. These several methods all first synthesize 4-nitrodiphenylamine or 4-nitrosodiphenylamine, and then reduce to obtain 4-aminodiphenylamine. [0004] The aniline me...

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Problems solved by technology

[0016] The technical problem to be solved by this invention is that in the literature about nitrobenzene method to prepare 4-aminodiphenylamine in the past, there are catalyzers that need precious metals, so that the catalyst preparation cost is high; the main impurity azobenzene oxide / azobenzene and / or hydroazobenzene needs to be recovered separately, prolonging the operation steps, increasing the production cost, or only using the shortcomings of pure raw materials, providing a new method for preparing 4-aminodiphenylamine