Green catalytic synthesis of p-aminophenol via hydrogenation of nitrobenzene

p-aminophenol(PAP) is an important chemical raw material and organic intermediates.A variety of synthesis routes and catalysts for the preparation of PAP form hydrogenation of nitrobenzene in absence of sulphuric acid medium had been studied in our early studies and was summarized in the paper.The catalyst system includes highly dispersed platinum-acidic ionic liquid catalyst,Pt/SiO2and acidic ionic liquid solid-liquid phase bifunctional catalyst,immobilized Pt-ionic liquid catalyst,Pt-superacid bifunctional catalyst,Pt-heteroatom substituted aluminophosphate molecular sieve catalyst,Pt-carbon-based solid acid catalyst and Pt-Lewis acid metal salt catalyst.The activity and selectivity of Pt-Lewis acid metal salt catalyst system are very close to the results of the industrial production catalyzed by sulphuric acid.This process has a good prospect for industrial application and the studies on industrial scale are now in progress.