Catalytic Hydrogenation Of Synthetic Aminophenol

p-Aminophenol (PAP for short) is an important intermediate and it is starting material for manufacture of pharmaceuticals and dyes, etc. But at present, the manufacture of p-Aminophenol in China is unsatisfactory with low yield and high pollutions.The synthesis of p-aminophenol was investigated and improved in this paper. Nitrobenzene was hydrogenated to give p-aminophenol. In aqueous sulfuric acid, nitrobenzene was hydrogenated with Pt/C catalyst to give p-aminophenol. Many factors which affect the reaction, such as reaction temperature, pressure of hydrogen, the dosage of surfactant, catalyst, pH value and reaction time have been studied. Best conditions are found in orthogonal test. The optimum reaction conditions are that the volume of nitrobenzene is 20mL; reaction temperature is 75℃; pressure of hydrogen is 2kPa; the reaction time is 4h; the amount of hexadecyltrimethylammonium bromide is 0.1 g; sulfuric acid concentration is 13%. Under the optimum condition, by using 2% catalyst, the selectivity of p-aminophenol could reach 90% .