Graphene encapsulated low-load nitrogen-doped bimetallic magnetic Pd/Fe@N/C catalyst for the reductive amination of nitroarene under mild conditions

Abstract

Aniline is a group of important platform molecules and is widely used in the synthesis of other high-value chemicals and pharmaceutical products. How to produce high-value anilines as the high-value chemical intermediates more efficiently and more environmentally has always been a research topic in the industry. Catalytic hydrogenation is an environmentally friendly method for preparing halogenated anilines. Traditional noble metals catalysis face cost and noble metals residue problems. To improve the purity of the product and the activity and recyclability of the catalyst, we prepared a Pd/Fe magnetic bimetallic catalyst supported on N-doped carbon materials to reduce nitrobenzene to aniline under mild conditions. The loading of Pd was very low, which was 1/10 of the content of common commercial precious metal Pd/C and Pt/C catalysts, which was only 0.5%. And the prepared bimetallic Pd/Fe@N/C catalyst showed excellent catalytic reactivity with the conversion rate of nitrobenzene > 99%, and the selectivity of aniline 99% under mild reaction conditions of 0.8 MPa H2 and 40 °C. A variety of halogenated and aliphatic nitro compounds were well tolerated and had been transformed to the corresponding target amine products with excellent selectivity. In addition, the novel N-doped graphene-encapsulated bimetallic magnetic Pd/Fe@N/C catalyst not only had magnetic physical properties, which was easy to separate, recover, and used for the recycling of the catalyst without metal leaching but also catalyzed highly selective reductive amination of aromatics was a green, economical and environmentally friendly reaction with the only H2O as a by-product.