Method for preparing 4-aminodiphenylamine

Abstract

The invention discloses a method for preparing 4-aminodiphenylamine, which comprises the following steps: (1) mixing aniline and an alkali water solution, and distilling out aniline-water azeotrope; (2) adding nitrobenzene to react; (3) adding water and a hydrogenation catalyst, and introducing hydrogen gas; (4) carrying out solid-liquid separation to separate the hydrogenation catalyst and a liquid phase, returning the hydrogenation catalyst to the step (3) or returning the hydrogenation catalyst to the step (3) after regeneration, separating the liquid phase to obtain an organic phase and an alkali water solution, rectifying the organic phase to obtain 4-aminodiphenylamine and aniline, and returning the aniline to the step (1); and (5) returning the alkali water solution to the step (1) or returning the alkali water solution to the step (1) after the alkali water solution is treated by activated carbon. In the method disclosed by the invention, the activated carbon is used for treating the circulating alkali water solution so as to remove impurities, thereby improving the purity of the circulating alkali water solution and avoiding the use of an expensive electrolytic process. Thus, the invention has the advantages of short process route and low equipment investment, is simple to operate, lowers the operating cost and reduces the environmental pollution.

Description

technical field [0001] The present invention relates to a kind of production method of 4-aminodiphenylamine. Background technique [0002] p-4-aminodiphenylamine (4-aminodiphenylamine) is an important fine chemical intermediate, which can be used in rubber additives, dyes, textiles, printing and pharmaceutical industries, etc., mainly used in the production of p-phenylenediamine rubber anti-aging Agent 4010NA, 4020, etc. There are four main production processes for p-4-aminodiphenylamine: aniline method, diphenylamine method, formanilide method and nitrobenzene method. Each of the four routes has its own characteristics. The aniline method is simple in process and low in cost, but has high reaction temperature, many side reactions, and poor product quality. The diphenylamine method mainly uses diphenylamine as a raw material. In the presence of inorganic acids, nitrosation is carried out with nitrite in an organic solvent to obtain N-nitrosodiphenylamine, which is then rea...

AI Technical Summary

Problems solved by technology

The four routes have their own characteristics. The aniline method is simple in process and low in cost, but the reaction temperature is high, side reactions are many, and the product quality is poor.

[0010] Although the electrolysis method can significantly improve the purity of the aqueous solution containing tetramethylammonium hydroxide, the investment in the electrolysis method equipment is very large, the power consumption is large, and the operating cost is high. Sometimes, fouling occurs on the anode during the electrolysis process and the electrolysis stops