Facile One-Pot Ultrasound-Assisted Reduction Synthesis of Pd/C Nanocatalyst for Green Suzuki-Miyaura Coupling

摘要

Palladium nanoparticles (Pd NPs) supported on active carbon was prepared via ultrasonically treating Pd precursors in ethylene glycol without any protective agents. The Pd/C nanocatalysts were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2-adsorption analysis, and X-ray photoelectron spectrometry (XPS). The results suggested that Pd NPs with an average particle size of 7.54 nm are formed in Pd/C-600W. Pd NPs of Pd/C-600 W nanocatalysts were highly distributed on the surface of active carbon. Even under mild conditions, Pd/C-600 W catalyst exhibited a better catalytic performance than that of Pd/C-T catalysts in Suzuki-Miyaura coupling reactions. The yield of 4-bromonitrobenzene reached 94.28% with only 0.1 mmol% Pd/C-600 W catalyst. Pd/C-600 W catalyst could be easily separated by filtration. It could be recycled four times with limited activity decrease. The catalytic activity and recyclability of Pd/C-600 W is higher than Pd/C-T. This ascribed to smaller size and more uniform dispersion of Pd/C-600 W.