Propylamine-containing magnetic ethyl-based organosilica with a core–shell structure: an efficient and highly stable nanocatalyst

Abstract

In the present study, a novel propylamine-containing magnetic organosilica (Fe₃O₄@OS-NH₂) material with a core–shell structure is prepared and characterized, and its catalytic performance is investigated in the one-pot condensation of aldehydes with ethyl cyanoacetate. The Fe₃O₄@OS-NH₂ catalyst was prepared through simultaneous hydrolysis and condensation of bis(triethoxysilyl)ethane and (3-aminopropyl)trimethoxysilane around magnetic iron oxide nanoparticles. Several techniques such as energy-dispersive X-ray spectroscopy (EDX), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD) and vibrating sample magnetometry (VSM) were applied to characterize the Fe₃O₄@OS-NH₂ catalyst. This nanomaterial showed an excellent efficiency in the Knovenagel condensation of aldehydes with ethyl cyanoacetate and gave the corresponding coupling products in high yields. This catalyst was also recovered and reused several times while retaining its performance and stability.