Studies On Cinnamic Acid Hydrogenation Over Nickel-based Nano Catalysts

Catalytic hydrogenation, as the representative of the atom economy reactions, conformsto the concept of green chemistry and is regarded as one of the most attractive research spotsin recent years. Catalyst is the core of the catalytic reactions and plays a significant role in thestudy of catalytic hydrogenation. Considering the high cost of noble metal catalysts, transitionmetal nickel was selected as the active species in this paper. A series of nano nickel-basedcatalysts was prepared for catalytic hydrogenation with the selective hydrogenation ofcinnamic acid being chosen as a model reaction. The relationship between the structure andhydrogenation performance of catalysts was particularly investigated.Firstly, a series of metal modified nano NiB amorphous alloy catalysts was prepared bychemical reduction. It was found that a Co modified NiB amorphous alloy (NiCoB) exhibitedexcellent catalytic performance in cinnamic acid hydrogenation, and the target producthydrocinnamic acid can be obtained in100%selectivity.Then, in order to solve the poor stability of nano NiCoB amorphous alloy, a γ-Al2O3supported NiCoB amorphous alloy catalyst (NiCoB/γ-Al2O3-u) was prepared by anultrasound-assisted impregnation-reduction method and investigated in the hydrogenation ofcinnamic acid. The results showed that this catalyst markedly deactivated only after three runsin water; whereas it can be recycled effectively for nine times in t-butanol. An efficient andstable catalytic system involving NiCoB/γ-Al2O3-u and t-butanol was then established forcinnamic acid hydrogenation. Furthermore, the loss of Ni species and the hydration ofγ-Al2O3support are regarded as the main reasons for the catalyst deactivation in water.Finally, a new magnetic nano core-shell Fe3O4@SiO2@NiPd catalyst was preliminaryprepared using a modified St ber-self-assembly method and tested in the hydrogenation ofcinnamic acid. The catalyst showed good catalytic performance in water and can beeffectively magnetic separated after reaction and recycled for many times, showing potentialapplications in hydrogenation.