Preparation and characterization of sulfamic acid-functionalized Fe₃O₄ nanoparticles as an efficient magnetic nanocatalyst for the facile and eco-friendly synthesis of quinoxalines, benzothiazoles, and benzoxazoles

In this study, we synthesized sulfamic acid-functionalized Fe₃O₄ nanoparticles (Fe₃O₄@EDA-SO₃H) as an effective nanomagnetic solid acid catalyst. This magnetically recoverable catalyst was well characterized by FT-IR, XRD, TGA, VSM, SEM, EDX, TEM, and CHN techniques. The prepared catalyst exhibited high efficiency in the synthesis of quinoxaline, benzothiazole, and benzoxazole derivatives such as 3,2-diphenylquinoxaline (97%), 2-phenyl-benzothiazole (97%), and 2-(4-chlorophenyl)benzoxazole (95%) via simple and mild conditions. The catalyst can be readily separated from the reaction medium by employing an external magnet and reused several times without significant loss of its catalytic activity.