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

Abstract

(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 α-pinene to form cis-pinane. The conversion of α-pinene was 99.1% and the selectivity for cis-pinane reached 97.6% at 120 °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 α-pinene conversion and the cis-pinane selectivity also can reach 97.8% and 96.9%, respectively.