Mild Hydrogenation of alpha-Pinene Catalyzed by Ru Nanoparticles Loaded on Boron-doped Amphiphilic Core-Shell Mesoporous Molecular Sieves

摘要

Highly dispersed and stable catalysts comprising Ru nanoparticles supported on boron-doped amphiphilic core-shell mesoporous molecular sieves (MMS-C@MMS-NH2/B/Ru) with alkyl-modified hydrophobic silica core and NH2-functionalized hydrophilic silica shell are successfully prepared for use in hydrogenation of alpha-pinene for the first time. Dodecyl-modified MMS-C-12@MMS-NH2/B/Ru exhibits the best catalytic activity under mild hydrogenation conditions. The abundant -NH2 functional groups on the molecular sieve surface and their amphipathy allow the sieves to facilitate attachment of more Ru nanoparticles, and to simplify their dispersion in the water-organic reaction medium. Moreover, B-doped molecular sieves may adjust their acidity to meet the needs of alpha-pinene hydrogenation. Under mild reaction conditions (25 degrees C, 1 MPa H-2, and 1 h), alpha-pinene can be completely converted with 99 % selectivity to cis-pinane, because every nanocomposite is equivalent to a microreactor. The catalytic activity does not change much over 5 cycles, indicating that Ru nanoparticles are stably loaded on the molecular sieves.