Iron-based nanoparticles embedded in a graphitic layer of carbon architectures as stable heterogeneous Friedel–Crafts acylation catalysts

Abstract

A series of carbon supported iron nanoparticle composites were prepared by pyrolysis of two kinds of Fe-MOF materials, Fe-diamine-dicarboxylic acid and Fe-dicarboxylic acid, and were characterized by a variety of characterization techniques. The composites pyrolyzed at higher temperatures are composed of iron-based nanoparticles (Fe₃C) and porous carbon architectures with graphitic characteristics. The catalytic properties of these composites were investigated for the Friedel–Crafts acylation of aromatic compounds with acyl chlorides. Among them, Fe@NC-800, derived from the pyrolysis of Fe-diamine-dicarboxylic acid at 800 °C, exhibited excellent catalytic activity and stability for the acylation reactions, and could be easily recycled several times without an obvious loss in activity. The excellent catalytic performance of Fe@NC-800 should be mainly attributed to the microstructural characteristics of the active sites, in which most of the small iron-based nanoparticles are encapsulated in the graphitic layer of the carbon architecture, thus providing a suitable geometric environment for stabilizing iron species. Besides, the electronic effects exerted by the graphitic layer of porous carbon may also play a positive role in improving the catalytic activity and stability of the carbon supported iron-based catalyst for Friedel–Crafts acylation reactions.