ABSTRACT:
A novel iron oxide nanoparticlc (Fe 3 0 4 @C-S 0 3 H) fabricated with carbon and sulfonic acid was prepared w,ing the concept of green chemistTy protocol. The usage of agro-waste extract for core -shell Fe 3 0 4 preparation and its biochar powder a.<;a carbon source for the fabrication of the catalyst was the dual benefit. T his prepared catalyst was employed for the synthesis of 4H-chromene derivative via a three-componen t one-pot reaction of resorcinol, aryl aldehyde , and malononitrile in ethanol under microwave irradiation. The method was found to be nontoxic, inexpensive, faster, and simple work-up with greener solvent, and gave excellent product isolation with about 91 % yield in 4 min microwave irradiation in the presence of 25 mg catalyst. The catalyst could be recovered after the reaction by an elttemal magnet and reused for up to four runs without any considerable loss in its catalytic activity. The prepared catalyst was characterized by Ff -TR, and prominent bands were observed for surface functionalization. The XRD data revealed prominent peaks for the formation ofFe 3 0 4 @C-S 0 3 H, and the results arc comparable with the reported literature; the VSM data gives a clear idea about the magnetic nature of the catalyst and respective surface-modified core shells, the surface morphology, and the required elements present are confirmed by FE-SEM and EDX . TGA admits that the thermal stability of the catalyst is up to 600 °C under a nitrogen atmosphere. The 1 H- & 13 C-NMR and LC-MS analysis arc explored for the analysis of the fonnation of final 2-arnino-4H-chromene derivatives. Further antimicrobial activities of the selected compounds were performed, and the results arc promising and comparable with the reference.
