Synthesis of Hexabenzylhexaazaisowurtzitane (HBIW) under Ultrasound Irradiation with Fe3O4@PCA Nanoparticles as an Efficient and Reusable Nanomagnetic Catalyst

Magnetic Fe3O4@polycitric acid (Fe3O4@PCA) nanoparticles were prepared by the reaction of Fe3O4 nanoparticles with an excess amount of citric acid at 100-160 °C. The magnetic Fe3O4@PCA nanoparticles were characterized by infrared spectroscopy (FTIR), scanning electron microscope (SEM), Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA) and powder X-ray diffraction (XRD). Finally, the synthesized magnetic Fe3O4@PCA nanoparticles were used as a heterogeneous solid acid catalyst for the synthesis of HBIW from benzylamine and glyoxal in acetonitrile-water solvent under ultrasonic irradiation conditions. The catalyst could be reused up to 6 times without significant loss of activity.