Fabrication and characterization of nickel ferrite encapsulated silica particles bearing triazine as an effective reusable solid base nanocatalyst for the synthesis of 4H-chromenes under mild conditions

Abstract

In this study, a core–shell nickel ferrite immobilized on a triazine-based nanocomposite was designed and prepared. This nanocomposite was prepared in four steps and characterized using FT-IR, XRD, FE-SEM, BET, TGA, EDS, elemental mapping, and VSM techniques. The tris(NiFe2O4@SiO2–PTT)–TA nano-sized powder was successfully employed as a heterogeneous nanocatalyst for the synthesis of 4H-chromenes from aromatic aldehydes, malononitrile, and 1,3-dimethyl dimedone in ethanol under reflux conditions. The reactions yielded products in good to excellent yields with short reaction times. The products were identified using melting points, FT-IR and 1H NMR analyses. Furthermore, the catalyst was easily separated using an external magnet and reused six times with only a marginal loss in its activity. The FT-IR and FESEM analyses of the recovered catalyst confirmed the preservation of its structure and morphology that remained intact. This method offers several advantages, including cost-effectiveness, easy access to materials, catalyst reusability, use of a green solvent, high product yields, simple separation, and mild reaction conditions.