Catalytic agent for preparing p-aminophenol by using nitrobenzene catalytic hydrogenation and preparation method thereof

Abstract

The invention relates to a novel catalytic agent for preparing p-aminophenol by using nitrobenzene catalytic hydrogenation and a preparation method thereof. The catalytic agent enables active carbon to serve as a carrier, enables Pt to serve as a main catalytic agent and enables MoS2 to serve as an auxiliary catalytic agent. The preparation step of the catalytic agent comprises (1) preparing Pt/C catalytic agent, namely enabling the Pt to be loaded on the activated carbon through an infusion process; and (2) restoring the auxiliary catalytic agent MoS2 through steeping and roasting under certain H2, loading on the Pt/C, and finally obtaining the catalytic agent for preparing the p-aminophenol. The catalytic agent for synthesizing the p-aminophenol is high in productivity and high in selectivity, and the catalytic agent is good in stability. After 23 times of circulation, the catalytic agent keeps good activity, yield coefficient of the p-aminophenol is above 83%, and the catalytic agent has good industrial application prospect.

Description

technical field [0001] The invention relates to the technical field of catalysts, in particular to a catalyst for preparing p-aminophenol from nitrobenzene and a preparation method thereof. Background technique [0002] P-aminophenol (abbreviated as PAP) is a widely used intermediate in organic synthesis. The traditional production route is the chlorobenzene route. Chlorobenzene is nitrated to obtain p-nitrochlorobenzene, then hydrolyzed to obtain p-nitrophenol, and finally undergoes a reduction method (iron powder, alkali sulfide or hydrogen) and other three-step chemical reactions and a series of separations. Process for the production of p-aminophenol. [0003] The route using nitrobenzene as a raw material, first, nitrobenzene is reduced by zinc powder, electrolysis or catalytic hydrogenation to generate p-hydroxyaniline, which can be directly rearranged by Bamberge to generate p-aminophenol under acidic conditions without separation. Among them, due to the low yield a...

AI Technical Summary

Problems solved by technology

The p-aminophenol synthetic method disclosed in US6403833 and CN1075489C has used nickel / ZSM-5 or Pt / nylon, although catalytic stability is better, but the selectivity of PAP is poor

In CN1562465A, Pt is loaded on the acidic bifunctional carrier, and there is a problem that the carrier is dissolved and lost by the acidic solution, and the life of the catalyst is unstable

CN1061808A electrolytically reduces nitrobenzene in acidic medium to generate p-aminophenol without using expensive catalysts. The disadvantage of this method is that the electrode material is difficult to resist corrosion