Assessment of a Pd–Fe3O4-biochar nanocomposite as a heterogeneous catalyst for the solvent-free Suzuki-Miyaura reaction

Abstract

The objective of this study was the development of a novel, biochar-based Pd nanocatalyst and its evaluation for the promotion of the Suzuki-Miyaura coupling reaction. The Fe3O4–Pd-biochar composite was successfully characterized through a range of spectroscopic and elemental analysis techniques. Its catalytic activity was initially assessed using p-NO2C6H4I as a model reactant and later for the production of biaryls from a wide range of aryl halides, under microwave irradiation and solvent-free conditions. The optimum yield of 99% was obtained at a catalyst dosage of 8 mg, microwave irradiation of 400 W, 6 min residence time, using K2CO3 as the base. Furthermore, the catalyst promoted the Suzuki-Miyaura reaction of aryl iodides and bromides (yields in the range of 88–97 and 86–97%, respectively), but was less successful for aryl chlorides (yields 78–83%). The presence of Fe3O4 allowed for the quick recovery of the catalyst, whereas repeated runs established its recyclability.