Underlying Mechanisms of Reductive Amination on Pd-Catalysts: The Unique Role of Hydroxyl Group in Generating Sterically Hindered Amine

Zeng Hong; Xin Ge; Shaodong Zhou

doi:10.3390/ijms23147621

Underlying Mechanisms of Reductive Amination on Pd-Catalysts: The Unique Role of Hydroxyl Group in Generating Sterically Hindered Amine

Int J Mol Sci. 2022 Jul 10;23(14):7621. doi: 10.3390/ijms23147621.

Authors

Zeng Hong^{1

2}, Xin Ge³, Shaodong Zhou^{1

2}

Affiliations

¹ Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
² Institute of Zhejiang University-Quzhou, 78 Jiuhua Boulevard North, Quzhou 324000, China.
³ School of Chemical and Material Engineering, Jiangnan University, Lihu Avenue 1800, Wuxi 214122, China.

Abstract

Pd nanospecies supported on porous g-C3N4 nanosheets were prepared for efficient reductive amination reactions. The structures of the catalysts were characterized via FTIR, XRD, XPS, SEM, TEM, and TG analysis, and the mechanisms were investigated using in situ ATR−FTIR spectroscopic analysis complemented by theoretical calculation. It transpired that the valence state of the Pd is not the dominating factor; rather, the hydroxyl group of the Pd(OH)2 cluster is crucial. Thus, by passing protons between different molecules, the hydroxyl group facilitates both the generation of the imine intermediate and the reduction of the C=N unit. As a result, the sterically hindered amines can be obtained at high selectivity (>90%) at room temperature.

Keywords: Pd-catalyst; competing mechanisms; in situ ATR–FTIR analysis; reductive amination; sterically hindered amine.

Underlying Mechanisms of Reductive Amination on Pd-Catalysts: The Unique Role of Hydroxyl Group in Generating Sterically Hindered Amine

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