Assembly and Post-modification of Fe 3 O 4 @MIL-100(Fe) for Knoevenagel Condensation

Many efforts have been devoted to the integration of magnetic nanoparticles and metal organic frameworks, which makes it easy and simple to separate the nano-sized metal organic frameworks from liquid phase. Amino-functionalized magnetic metal organic frameworks[Fe3O4@MIL-100(Fe)-NH2] were prepared by a stepwise assembly method followed by post-modification with electron-rich reagent. This magnetic catalyst was characterized by means of X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM) and nitrogen adsorption, and tested in Knoevenagel condensation as a base catalyst. The magnetic catalyst exhibits a core-shell structure and can afford a high activity for the Knoevenagel condensation due to its bifunctional property and reduced diffusion limitation. Furthermore, it could be recovered magnetically and recycled three times. Although activity loss was observed in the recycle experiments, it could be reactivated by dispersing in a fresh modifier solution.