Biosynthesis, characterization and catalytic activity of Cu/RGO/Fe3O4 for direct cyanation of aldehydes with K4[Fe(CN)6]

[Display omitted] •Green synthesis of Cu/RGO/Fe3O4 nanocomposite using Euphorbia bungei Boiss leaf extract.•Cyanation of aldehydes with K4[Fe(CN)6].•Characterization of catalyst by XRD, FESEM, EDS, elemental mapping and UV–Vis.•The catalyst can be recovered and reused for further catalytic reactions with almost no loss in activity. This work reports the green synthesis of the Cu/reduced graphene oxide/Fe3O4 (Cu/RGO/Fe3O4) nanocomposite as a new catalytic system for cyanation of aldehydes to nitriles. This nanocomposite catalytic system was synthesized by aqueous extract of leaves of Euphorbia bungei Boiss as a reducing and stabilizing agent. Various substituted aryl nitrile were prepared under optimized conditions and providing moderate to excellent yields. In this process the catalyst exhibited a strong magnet response and could be easily separated by an external magnet and reused with no loss of catalytic activity.