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

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 p-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.

Zerovalent ruthenium nanoparticles can be efficiently stabilized by randomly methylated cyclodextrins (CDs) from chemical reduction of ruthenium salt in water followed by their adsorption onto a carbon support. The optimization of the Ru-CD catalytic systems has been carried out by evaluating the gas phase hydrogenation of xylenes under mild reaction conditions, tested separately and in a two-component mixture..Figure optionsDownload high-quality image (86 K)Download as PowerPoint slideResearch highlights▶ Preparation of ruthenium nanoparticles on activated carbon under mild conditions. ▶ Use of non toxic oligosaccharides as pre-stabilizers. ▶ Enhancement of catalytic performances in xylene hydrogenation at 85 °C. ▶ Best performances with RaMe-β-CD in a single and two-component mixture. ▶ No pre-reduction at high-temperature.