Design and synthesis of Fe3O4/MPL-[IL] as a novel and efficient magnetic nanocatalyst for the synthesis of benzo[5,6]chromeno[2,3-b]quinolin derivatives

The magnetic lignin particles were successfully functionalized with the Brønsted-acidic ionic liquid, 1-(propyl-3-sulfonate) vinyl imidazolium hydrogen sulfate, through surface anchoring techniques. To characterize the resulting Fe3O4/MPL-[IL] nanocomposite, various analytical methods, including FE-SEM, EDS, FT-IR, XRD, TEM, and VSM analysis, were used. The combined effect of the magnetic support structure and the flexible imidazolium-based ionic liquid enabled catalytic performance comparable to that seen in homogeneous systems. This hybrid catalyst demonstrated high effectiveness in the reaction between cyclohexanone and 2-amino-4-aryl-4H-benzo[f]chromene-3-carbonitrile derivatives, resulting in the synthesis of benzo [5,6]chromeno[2,3-b]quinolins. Key features of the Fe₃O₄/MPL-[IL] catalyst include its environmentally friendly nature, easy recovery through magnetic separation, and reliable reusability over multiple reaction cycles without losing magnetic integrity.