Hydrogenation of nitrobenzene to p-aminophenol using Pt/C catalyst and carbon-based solid acid

Liquid phase hydrogenation of nitrobenzene to p-aminophenol (PAP) in water was studied over a catalyst system composed of Pt/C and carbon-based solid acid which was prepared by one-step hydrothermal carbonization of various carbon sources including starch, sucrose, glucose and furfural in sulfuric acid aqueous solution at 180 °C for 4 h. The effects of carbon-based solid acid type, Pt/C catalyst loading, hydrogen pressure and reaction temperature on nitrobenzene conversion and PAP selectivity were investigated. The results showed that PAP selectivity was favored at high acid density of the carbon-based solid acid. The carbon-based solid acid prepared from starch, with the highest SO3H amount, gave the highest PAP selectivity among the catalysts used. An increase in Pt/C catalyst loading led to an increased nitrobenzene conversion but a decreased PAP selectivity. A high reaction temperature was in favor of nitrobenzene conversion and PAP selectivity. Under the optimal reaction conditions, nitrobenzene conversion and PAP selectivity reached 61.0% and 77.8%, respectively.