Bismuth iron oxide nanocomposite supported on graphene oxides as the high efficient, stable and reusable catalysts for the reduction of nitroarenes under continuous flow conditions

Abstract

An efficient catalyst made of bismuth, iron and graphene oxide composite was developed for the reduction of nitroarenes with hydrazine hydrate to afford corresponding anilines. We found that the bismuth and graphene remarkably promoted the activity of iron oxide catalyst, so that a mixture of ferric chloride, bismuth nitrate and graphene oxide catalyzed the complete conversion of 4-nitrophenol into 4-aminophenol. Moreover, a catalyst prepared from the co-precipitation of bismuth, iron and graphene oxide nanocomposite (BFGO) exhibited perfect performance, and it could be recovered magnetically and reused for ten cycles without any activity losing. Furthermore, another heterogeneous catalyst tBFGO was constructed from the bismuth iron oxide nanocomposite with thermal exfoliated graphene. It was a robust and sustainable catalyst and was suitable to be used in the continuous flow microreactor. Applying a catalyst cartridge that filled up with tBFGO, a series of functionalized nitroarenes were successfully converted into corresponding anilines with excellent selectivity, and the work-up procedure was very easy. The catalytic activity of the catalyst did not decline within more than 600min under a flow rate of 1mL/min.