Synthesis, characterization, and a comparative study on the catalytic activity of the functionalized magnetic nanoparticles for the green oxidation of sulfides

Abstract

In the following research, meso-tetrakis(4-carboxyphenyl)porphyrinatomanganese (III) acetate (MnTCPP(OAc)) was immobilized onto the surface of two functionalized magnetic nanoparticles (MNPs) with different linker length via amide bond (Fe₃O₄@SiO₂-NH₂-MnTCPP(OAc) (A¹) and Fe₃O₄@SiO₂-NHCO-NH₂-MnTCPP(OAc) (A²)). The prepared catalysts were characterized by standard methods such as: atomic absorption spectroscopy (AAS), Ultra violet-visible (UV-Vis), Fourier-transform infrared (FT-IR), vibrating sample magnetometry (VSM), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) techniques and also the effect of the length of the linker on the catalytic activity of supported magnetic nanohybrids was investigated. The prepared magnetic nano-catalysts with different linker lengths were participated in a comparative study of the clean oxidation of sulfides with urea hydrogen peroxide (UHP) in ethanol. The higher catalytic activity, selectivity and also reusability were achieved in the presence of the catalyst with longer linker length (A²) at ambient temperature. Moreover, the turnover number (TON) of catalytic reactions using A² as catalyst was highly enough to consider the catalyst as an efficient material to oxidize various sulfides. Both A¹ and A² catalysts simply have accomplished 5 runs of recycling without significant decrease in the catalytic activity.