Synthesis of silanized magnetic Ru/Fe3O4@SiO2 nanospheres and their high selectivity to prepare cis-pinane

(3-Aminopropyl)-triethoxysilane (APTS) and (3-mercaptopropyl)-trimethoxysilane (MPTS) grafted SiO2-coated iron oxide (Fe3O4@SiO2) magnetic supports were prepared. Various noble metal nanoparticles such as Ru, Pt, Rh and Pd were directly grown on the surfaces of the magnetic supports with ultrasmall and nearly monodisperse sizes, especially the APTS grafted Fe3O4@SiO2 (Fe3O4@SiO2/APTS) nanospheres. The Fe3O4@SiO2/APTS/Ru catalyst demonstrated a high catalytic activity towards the hydrogenation of alpha-pinene to form cis-pinane. The conversion of alpha-pinene was 99.1% and the selectivity for cis-pinane reached 97.6% at 120 degrees C after 4 h. The Fe3O4@SiO2/APTS/Ru catalyst was easily separated from the reaction mixture when applying an external magnetic field, and the separated Fe3O4@SiO2/APTS/Ru had good reusability. After being reused eight times, the alpha-pinene conversion and the cis-pinane selectivity also can reach 97.8% and 96.9%, respectively.