Selective Amination of Benzaldehyde over the Fine Ru Nanoparticles Anchored in NiO Catalysts

Abstract

The selective amination of benzaldehyde (BZH) is one of the important industrial reactions for the production of fine chemicals. Herein, we synthesized a Ru/NiO nanocatalyst with an extremely low loading of noble metals (0.22%) via a facile ball-milling method efficient for the conversion of BZH to N-benzylidenebenzylamine (N-BDB). Compared with the benchmark im-Ru/NiO catalyst prepared via the traditional impregnation (im) method, the Ru/NiO catalyst exhibited the higher yield of N-BDB, with a full conversion of BZH and a 91.5% selectivity to N-BDB in 0.1 MPa NH3 and 2 MPa H2 pressure. After that, various parameters that influenced the catalytic performance and potential reaction pathway were investigated. In addition, the catalyst maintained high stability, which could be recycled even for five runs without obvious deactivation. Extensive characterizations verified that the H2 activation ability of Ru and the overall acidity of the Ru/NiO catalyst were improved, which should account for the superior catalytic performance. This work provides a facile strategy of catalyst synthesis for the selective production of fine chemicals.