Synthesis, Structural Analysis of Single Phase Nickel Ferrite (NiFe2O4) and their Application for Green Synthesis of 2-Amino-3-cyanopyridines

A single-phase nickel ferrite (NiFe2O4) catalyst was synthesized using a straightforward chemical oxalate method with oxalic acid as precipitating agent. The structural and morphological properties of the prepared nickel ferrite catalyst were analyzed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) techniques. The average crystallite size of NiFe2O4 was determined to be 37 nm, calculated using the Debye-Scherrer equation from the XRD analysis. Following the structural characterization, the catalytic efficiency of nickel ferrite was evaluated in the synthesis of 2-amino-3-cyanopyridine derivatives through a multicomponent reaction involving various aromatic aldehydes, malononitrile and cyclohexanone at room temperature. The NiFe2O4 effectively catalyzed the synthesis of 2-amino-3-cyanopyridine derivatives, yielding excellent product results in a very short reaction time under stirring at room temperature. Notably, the nickel ferrite catalyst could be easily recovered using an external magnet and reused four times without significant loss of catalytic efficiency.