Ziliang Yuan,Xun Li,Guanghui Wang,Zhihua Zhu,Yuhe Liao,Zehui Zhang,Bing Liu
The selective hydrogenation of N -heteroarenes into N -heterocycles is a highly important organic transformation in fine chemical industry, as N -heterocycles are moieties in a variety of pharmaceutical and bioactive compounds. Here, we report highly efficient mesoporous CeO 2 supported Ni catalysts prepared by the incipient wet impregnation and following high-temperature reduction for the selective hydrogenation of N -heteroarenes. The experiments indicated that the synergistic effect between CeO 2 and Ni nanoparticles was responsible to the superior catalytic performance. Various kinds of N -heterocycles were obtained at 120 °C with yields of 86 ∼ >99%, demonstrating the versatility of the developed method. This work is valuable for guiding the design and manipulation of low metal loading, cost-effective and robust hydrogenation catalysts.
The development of bifunctional catalysts for the efficient hydrogenation and acceptorless dehydrogenation of N -heterocycles is a challenge. In this study, Ru 2 P/AC effectively promoted reversible transformations between unsaturated and saturated N -heterocycles affording yields of 98% and 99%, respectively. Moreover, a remarkable enhancement in the reusability of Ru 2 P/AC was observed compared with other Ru-based catalysts. According to density functional theory calculations, the superior performance of Ru 2 P/AC was ascribed to specific synergistic factors, namely geometric and electronic effects induced by P. P greatly reduced the large Ru-Ru ensembles and finely modified the electronic structures, leading to a low reaction barrier and high desorption ability of the catalyst, further boosting the hydrogenation and acceptorless dehydrogenation processes.
The development of highly efficient non-noble metal catalysts for the hydrogenation of N-heteroarenes under mild condition is of great importance for both theoretical and industrial applications, which can efficiently reduce energy consumption and environmental pollution. In this work, we found that the prepared CoCu nano-alloy catalyst after exposed in the air over 24 h (named Co 1 Cu 1 /C) exhibited a dramatically improved catalytic performance (yield from trace to >99%) for quinoline hydrogenation under mild reaction conditions (60 °C, 3 MPa H 2 ). According to the characterization, the catalyst Co 1 Cu 1 /C exhibited the strong interaction between Co and Cu. Meanwhile, it was endowed with a stable partial oxidation surface. The unsaturated oxygen coordinated surface of Co 1 Cu 1 /C presented a moderate binding for quinoline and 1, 2, 3, 4-tetrahydroquinoline, which could efficiently avoid the deactivation of catalyst and favor the hydrogenation kinetics. The density functional theory (DFT) calculations coupled with X ray-based structural analyses suggested that the unsaturated oxygen coordinated surface could lower the diffusion energy of the active hydrogen species and the reaction barrier for quinoline hydrogenation which resulted from the d - p orbital electron coupling. This work revealed that the catalytic performance of nano-alloy catalysts might not only be ascribed to the interaction between metals, while the unsaturated oxygen coordination of metallic surfaces played an important role.
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