Synthesis of 2-amino-4,6-diarylnicotinonitrile in the presence of CoFe2O4@SiO2-SO3H as a reusable solid acid nanocatalyst under microwave irradiation in solvent-freeconditions

The modification of silica-coated CoFe2O4 magnetic nanoparticles (CoFe2O4@SiO2) with chlorosulfonic acid, which can be utilized as an organic-inorganic hybrid heterogeneous catalyst, introduces an astonishing and efficient system for the synthesis and simplicity of the recovery of the catalyst. The applied CoFe2O4 magnetic nanoparticles are 22.98-45.30 nm measured that can be utilized as a catalyst for the preparation of 2-amino-4,6-diarylnicotinonitrile under microwave irradiation in solvent-free conditions by four component reaction of aromatic acetophenone, aldehydes analogues, malononitrile and ammonium acetate. The so synthesized magnetic nanocatalyst was characterized by X-ray powder diffraction, SEM, TGA and FT-IR techniques. This simple protocol suggests advantages such as shorter reaction times, high yield, catalyst recovery, achieving the high purity of products by simple recrystallization and facile work-up. Other noticeable characteristics contain the catalyst can be recovered at least five times without any clear decrease in its catalytic activity. Graphical abstract Synthesis of 2-amino-4,6-diarylnicotinonitrile in the presence of CoFe2O4@SiO2-SO3H as a reusable solid acid catalyst under microwave irradiation in solvent-free conditions.