New core-shell catalyst for catalyzing hydrogenation of α-pinene to cis-pinane

Improving the selectivity of catalytic hydrogenation by designing new catalysts is an effective strategy for preparing cis-pinane. However, the stability of the reported catalyst is generally poor, and one of the main reasons is that metal active site is easy to drop. To address the issues, a new type of core–shell catalyst SiO2@Pd-Ni@mSiO2 is designed. The active metals can sandwich between the core and the shell, effectively preventing the dropping to enhance the related stability. The SiO2@Pd-Ni@mSiO2 shows outstanding stereoselectivity for the desired product, owing to its adsorption characteristics of shell pores, which can effectively promote α-pinene molecules directional adsorption, consequently enhancing the directional selective hydrogenation reaction of α-pinene with active metals and active hydrogen occurs in the interlayer. The conversion of α-pinene and the selectivity for cis-pinane are 99.4% and 93.3% under mild reaction conditions, respectively. Meanwhile, the catalyst SiO2@Pd-Ni@mSiO2 also has outstanding reusability. The preparation strategy of the new catalyst provides a new path for preparing efficient and stable catalysts for the hydrogenation of α-pinene.