Coal tar- and residual oil-derived porous carbon as metal-free catalyst for nitroarene reduction to aminoarene

Abstract

Nitroarenes reduction is an important technology in the industrial production of aminoarenes. In this work, we presented an environment-friendly and low-cost green synthesis route for preparation of oxygen and nitrogen co-doped porous carbon (ONPC) via acid oxidation and alkali activation methods using coal tar- and residual oil-based as starting materials, and the prepared ONPC was employed as metal-free carbon catalyst for nitroarenes reduction to aminoarenes in the presence of hydrazine hydrate. This ONPC catalyst showed much higher catalytic activity as compared to those of un-doped porous carbon (PC), activated carbon (AC) and carbon black, which was attributed to its large surface area and developed pore structure as well as O and N co-doping. Additionally, it also exhibited a versatility in various aromatic nitro-compounds reduction to relative aromatic amines. Experimental results by using model catalysts to simulate different carbons with various oxygen-containing groups proved that carbonyl groups were more favorable for nitrobenzene reduction to aniline. Upon co-doping O and N into PC, the two kinds of introduced species synergistically promoted the catalytic activity of PC. Good performance together with low-cost preparation makes oxygen and nitrogen co-doped porous carbon a potential substitution of supported metal catalyst for nitroarenes reduction.