Silica sulfuric acid coated on SnFe₂O₄ MNPs: synthesis, characterization and catalytic applications in the synthesis of polyhydroquinolines

An efficient and heterogeneous novel magnetic solid sulfuric acid, immobilized on silica functionalized SnFe₂O₄, was successfully synthesized, characterized, and employed as a novel recoverable nanocatalyst for the synthesis of biologically active polyhydroquinoline derivatives. The SnFe₂O₄@SiO₂-SO₃H was easily synthesized and confirmed using various spectroscopic techniques, including FT-IR, XRD, EDX, Map, TGA, SEM and TEM analyses. The catalytic behavior of the resulting catalyst system was investigated in the Hantzsch synthesis of polyhydroquinoline derivatives. The desired products were obtained with high conversions and excellent reusability.