Magnetic carbon nanotubes mesoporous silica nanocomposite functionalized with copper: Synthesis, characterization, and application for the efficient catalytic preparation of dihydrano-choromenes

Abstract

Nanoparticles of Fe3O4 were prepared and immobilized onto the surface of carbon nanotube (CNTs), followed by copper immobilization on the nanoparticles. The resulting MWCNT@Fe3O4@SiO2@CPTMO@DEA/Cu(II) nanocatalysts were characterized using Fourier transform infrared spectroscopy, X-ray diffraction patterns, scanning electron microscopy, energy dispersive X-ray spectroscopy, vibrating sample magnetometer, and thermal gravimetric analysis. The catalyst was then employed for the benign synthesis of 3,4-dihydropyrano[3,2-c]chromene derivatives. The main advantages of this work are high efficiency, short reaction time, simple operation and easy separation of the catalyst from the reaction mixture using an external magnet. The catalyst was magnetically retrieved and reused for six sequential cycles without significant loss of activity or re-selection. Furthermore, this method exhibits superior characteristics, including high efficiency, short reaction time and simple separation operation, compared to traditional dihydropyran-chromene reactions and other methods.