Magnetically recyclable Pd/γ-AlOOH@Fe3O4 catalysts and their catalytic performance for the Heck coupling reaction

Novel magnetically recyclable Pd/gamma-AlOOH@Fe3O4 catalysts were prepared using gamma-AlOOH@Fe3O4 as a magnetic supporter and nano-Pd particles as the active catalytic component. The structure of the catalysts was characterized by XRD (X-ray diffraction), TEM (transmission electron microscopy), N-2 adsorption-desorption, and a VSM (vibration sample magnetometer). The catalytic activity and recyclability for the Heck coupling reaction were investigated. Results showed that the magnetic gamma-AlOOH@Fe3O4 possessed a core-shell structure, as well as that the nano-Pd particles were 6-8 nm and had been well dispersed in the gamma-AlOOH shell. In the Heck coupling reactions, the magnetic Pd/gamma-AlOOH@Fe3O4 catalysts exhibited good catalytic activity and recyclability. For the (0.021 mol%)Pd/gamma-AlOOH@Fe3O4 catalyst, the bromobenzene conversion and product yield reached about 100% and 96.3%, respectively, under a 120A degrees C reaction temperature and 12 h reaction time. After being recycled 8 times, the conversion of bromobenzene and the recovery of the catalyst were about 90% and 93%, respectively. The nano-Pd particles were kept well dispersed in the used Pd/gamma-AlOOH@Fe3O4 catalyst.