Benzophenone Hydrogenation Catalyzed By Ni-B Amorphous Alloy Catalysts

Catalytic hydrogenation is one of the most effective methods of green chemistry. Presently, most studies are focused on precious metal catalysts. However, the high price and the shortage of such precious metals will become increasingly problematic in industrial applications, so it is of great importance to find active, non-precious metal catalysts to replace current precious metal catalysts. In past decades, amorphous alloy catalysts have been widely studied owing to their higher activity and better selectivity than the corresponding crystalline catalysts.The liquid-phase selective hydrogenation of benzophenone to benzhydrol has been investigated over Ni-B amorphous alloy catalysts, and a detailed reaction mechanism has been proposed based on GC-MS. La-doped Ni-B exhibits smaller particle sizes and more active centers, but more obvious agglomeration compared with Ni-B. The agglomeration can be inhibited by application of ultrasound; wherein the surface of the catalyst becomes homogeneous and the coverage of Ni centers is decreased correspondingly. The ultrasonic-assisted Ni-La-B catalyst is found to have better catalytic performance than Ni-B, Ni-La-B and Raney Ni, which can be attributed to the synergistic effect between La addition and ultrasound. The conversion of raw material reached 99.8% and the selectivity to benzhydrol was about 90.0% under the optimal reaction conditions.Considering the surface area, mechanical strength, thermo stability, active centers could be enhanced by supports and some interactions between supports and active centers may improve the performance of catalysts. A series of supported amorphous alloy catalysts were prepared by the chemical reduction method. Ultrasonic was introduced into the preparation step. The catalysts activity was tested in the selective hydrogenation of benzophenond to benzhydrol. SiO₂ andγ-Al₂O₃ were found to have better function among all the supports studied. Through the contrast research of the two supported catalysts, found that have different performances in reaction activity and life conversion. The catalysts with these two supports were characterized by BET, XRD, SEM, XPS, NH3-TPD and H2-TPD. The result shows that the different performances were based on the different physicochemical properties of the two carriers.