Process for synthesizing p-aminophenol by nitrobenzene catalytic hydrogenation

Abstract

The invention relates to a technique of synthesizing paraaminophenol by catalyzing and dydrogenating nitrobenzene, and belongs to the technical field of aminophenol. The invention is the technique of producing the paraaminophenol from the nitrobenzene catalyzing dydrogenating device in the metal salt liquors, wherein, the quality compounding rate of the material has a mass distribution ratio that Lewis acid metal salt: load metal Pt activator: nitrobenzene: hexadecyl trimethyl ammonium bromide: water is equal to 0.5 to 5 : 0.1 to 0.3 : 1 to 5 : 0.01 : 50. The invention has the reacting conditions that: a branch pressure of the hydrogen is 0.1 to 1.0 M Pa, a reacting temperature is 80 to 200 DEG C, and a reacting time is 1 to 10 hours. The reaction which is proceed in the neutral or acidulous metal salt liquors has not high requirements to the device material, thereby preventing using abundant ammonia during the managing process, simplifying the production craftworks and overcoming the problems of the canker of the device and the serious environmental pollution; the metal salt and the activators can be separated from the reaction system for being reused repeatedly; therefore, the invention reduces the production cost, also prevents the discharging of the waste liquids and makes the yield of PAP highly reach to 25 to 73 percents.

Description

Technical field [0001] The technical scheme of the present invention belongs to aminophenol, specifically a process for synthesizing p-aminophenol from nitrobenzene catalytic hydrogenation. Background technique [0002] P-Aminophenol (PAP for short) is an important intermediate in the synthesis of medicines, pesticides and dyes, and can be used as rubber antioxidants. The world's demand for PAP is increasing year by year. There are many reports on the synthesis of p-aminophenol at home and abroad, mainly including: p-nitrophenol iron powder reduction method, nitrobenzene catalytic hydrogenation method and nitrobenzene electrolytic reduction method. The p-nitrophenol iron powder reduction method (also known as the Boqian method) has gradually restricted its production due to high production costs, poor product quality, and serious pollution from the "three wastes". Two processes, catalytic hydrogenation of nitrobenzene and electrolytic reduction of nitrobenzene, are the most advan...

AI Technical Summary

Problems solved by technology

[0005] US 6028227 proposes to use ion exchange resin and Pt-S / C at the same time, mix nitrobenzene with water and carry out catalytic hydrogenation under the conditions of reaction pressure 20-27atm and reaction temperature 80°C, but the yield of PAP is only 13.9%

CN1562465A discloses with HF-SiO2, H-ZSM5 and load-type heteropolyacid as the method for carrier preparation Pt-solid acid bifunctional catalyst, although this catalyzer has reduced reaction to the demand of sulfuric acid concentration to a certain extent, but in non- Catalyst activity in acidic media is very low