P-aminophenol

P-aminophenol (PAP) is a vital chemical material and organic intermediate, wide employed in medicine, dye, rubber and different fields. In the process of producing p-aminophenol, the catalytic hydrogenation of nitrobenzene (NB) to p-aminophenol is the most industrially exploitable value. The reaction requires the hydrogenation catalyst and the acid catalyst to constitute the catalyst system. In traditional methods, sulfuric acid is used as the acid catalyst, and noble metals such as Pt, Pd, and Ru are used as the hydrogenation catalyst, and the catalytic activity is decreased in the order of Pt>Pd>Ru. However, the use of sulfuric acid can easily cause equipment corrosion and environmental pollution. Therefore, the use of environmentally friendly solid acid instead of traditional sulfuric acid can reduce waste liquid discharge, and the solid acid is easy to separate, non-corrosive, reusable, safe to transport, and easy to use. Sulfated metal oxides (SO42-/MxOy type) solid superacids, aluminosilicate molecular sieves1and other catalytic systems composed of solid acids and precious metals have shown good catalytic activity.