Preparation method of p-aminophenol

Abstract

The invention relates to a preparation method of p-aminophenol in the technical field of fine chemical products. It discloses a process for obtaining p-aminophenol by using an aqueous solution of sodium p-nitrophenolate for continuous hydrogenation reduction reaction and acidification reaction. The whole process flow is short and the production capacity is high. Large, low equipment investment, low overall cost, improved product yield, reduced labor intensity, reduced waste water generation, and no waste residue. The invention has significant economic and social benefits. The anti-aging agent for the synthesis of related products in the rubber industry and the production of related dyes in the dye industry create conditions for providing high-quality raw materials.

Description

technical field [0001] The invention relates to a preparation method in the technical field of fine chemical products, in particular to a preparation method of p-aminophenol. Background technique [0002] p-Aminophenol, referred to as PAP, is an important fine chemical product. In the pharmaceutical industry, PAP is mainly used to synthesize paracetamol, clofibrate, vitamin B, and complex agent nicotinamide. In the rubber industry, 4010NA, 4020, 4030 and other p-phenylenediamine antioxidants can be synthesized. It is also an intermediate for the production of disperse dyes, acid dyes, direct dyes, sulfur dyes and fur dyes. [0003] The existing production methods of p-aminophenol include iron powder method, p-nitrophenol hydrogenation reduction method, nitrobenzene hydrogenation reduction method and nitrobenzene electrolytic reduction method. The so-called iron powder method uses p-nitrochlorobenzene as a raw material and hydrolyzes it in an autoclave at 168-175°C and 0.75-...

AI Technical Summary

Problems solved by technology

[0006] 2. The "pollution" of the three wastes by iron powder reduction is serious, and there is waste water, waste residue and iron sludge. Every ton of p-aminophenol produced produces 30 tons of waste water and 3 tons of iron sludge

[0007] 3. The nitrobenzene catalytic reduction method has defects such as difficulty in catalyst recovery and mechanical application, high equipment requirements, troublesome post-treatment separation, high overall cost, and slow industrialization process

[0008] 4. There are many by-products in the nitrobenzene electrolytic reduction method, and the yield is restricted by various factors. At present, it only stays in the stage of small-scale and pilot-scale research. The real industrialization still needs to solve a series of engineering problems

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