Magnetic silica supported propylamine/H3PW12O40: A powerful and highly stable nanocatalyst for synthesis of tetrahydrobenzopyrans

Herein, a novel propylamine-containing magnetic silica supported ammonium phosphotungstate (MS/AP-PTA) is prepared via grafting of propylamine on magnetic silica (MS) followed by treatment with phosphotungstic acid. The MS/AP-PTA nanocomposite was characterized by using FT-IR, PXRD, TGA, EDX, VSM and SEM techniques. These analyses showed a core-shell structure with high chemical and thermal stability for the designed material. The MS/AP-PTA nanocomposite was used as a powerful and efficient nanocatalyst in the synthesis of bioactive tetrahydrobenzo[b]pyrans at room temperature under green conditions. The desired products were obtained in high yields at short reaction time. The leaching and recovery tests as well as FT-IR analysis showed high stability of catalytically active species and also the heterogeneous nature of the MS/AP-PTA nanocatalyst.