Chemically modified cyclodextrins as supramolecular tools to generate carbon-supported ruthenium nanoparticles: An application towards gas phase hydrogenation

摘要

A series of carbon-supported ruthenium catalysts was synthesized from zerovalent ruthenium nanoparticles stabilized by randomly methylated cyclodextrins (α-,β- and γ-CD) followed by their adsorption onto the carbon support. The catalysts were characterized by N2 physisorption and thermal analyses. The deposited ruthenium nanoparticles were characterized by transmission electron microscopy, which has highlighted predominantly spherical shapes with a mean diameter of 2.4 nm. Catalytic activity was investigated in the gas phase hydrogenation of o-, m- and β-xylene at 85 °C, both separately and in a two-component mixture (o- and p-xylene). The catalyst prepared by a 1:3 concentration ratio of RuCl3 to randomly methylated β-cyclodextrin exhibited the highest hydrogenation activity and stereoselectivity toward the formation of trans-dimethylcyclohexane. The β-cyclodextrin appeared as multifunctional molecular receptors enabling the stabilization and dispersion of the metallic nanoparticles onto the support and the promotion of the catalytic reaction through host-guest interactions.