Highly dispersed and stable Pd nano-catalyst loaded on chitosan nanoporous carbon microspheres for one-pot reductive amination of amines with aldehydes

Under the background of green/sustainable chemistry, it is still a challenge to synthesize green, efficient and stable catalysts for important chemical products. Herein, we reported a series of Pd nano-catalysts supported on chitosan nanoporous carbon microspheres (CNCM) derived from renewable resource chitosan, and used them for one-pot reductive amination of amines with aldehydes. Various physicochemical characterizations provided reliable evidences that the Pd nanoparticles (NPs) were uniformly dispersed on these CNCM with mean diameters from about 2.29-9.74 nm. As the carrier, CNCM had a nanoporous structure, which was conducive to the adhesion and dispersion of Pd NPs. Meanwhile, the inherent N/O-containing groups in CNCM and the formed defect interfaces during calcination process could anchor the Pd NPs firmly. These CNCM supported catalysts were utilized in the reaction of one-pot reductive amination, which showed excellent catalytic activity compared to various commercial Pd catalysts, as well good cyclic stability and broad substrate suitability.