Transfer hydrogenation of cellulose to sugar alcohols over supported ruthenium catalysts

Ru/C catalysts are active for the conversion of cellulose using 2-propanol or H2 of 0.8 MPa as sources of hydrogen, whereas Ru/Al2O3 catalyst is inactive in both reactions, indicating that the Ru/C catalysts are remarkably effective for the cellulose conversion

Simultaneous formation of sorbitol and gluconic acid from cellobiose using carbon-supported ruthenium catalysts

A carbon-supported Ru catalyst, Ru/BP2000, is able to simultaneously convert cellobiose into sorbitol and gluconic acid. This reaction occurs as the result of hydrolytic disproportionation in water at 393 K under an Ar atmosphere, without bases or sacrificial reagents. In-situ XANES measurements suggest that the active Ru species involved is composed of partially oxidized Ru metal

Catalysis and characterization of carbon-supported ruthenium for cellulose hydrolysis

Ru catalyst supported on mesoporous carbon CMK-3 shows high activity and durability for the hydrolysis of cellulose to glucose in hot compressed water at 503 K. The Ru/CMK-3 catalyst also hydrolyzes cellobiose to glucose in water at 393 K. Several physicochemical methods such as XRD, TEM, XPS, H2-TPR, O2-titration, and XAFS were used to characterize active Ru species on CMK-3 and to clarify the formation pathway of the active species. From these studies, we conclude that hydrous Ru oxide RuO2・2H2O is formed on CMK-3 after H2-reduction of RuCl3/CMK-3 at 673 K and subsequent passivation at room temperature, and that the Ru oxide nanoparticles with a mean diameter of 1.1 nm are highly dispersed on CMK-3

Chemo-microbial conversion of cellulose into polyhydroxybutyrate through ruthenium-catalyzed hydrolysis of cellulose into glucose

Cellulose-derived glucose generated using the supported ruthenium catalyst was applied to poly(3-hydroxybutyrate) [P(3HB)] production in recombinant Escherichia coli. By the reaction with the catalyst at 220 ℃, 15 to 20 carbon mol% of cellulose was converted into glucose. The hydrolysate also contained byproducts such as fructose, mannose, levoglucosan, oligomeric cellulose, 5-hydroxymethylfurfural (5-HMF), and furfural together with unidentified compounds. Setting the reaction temperature lower (215 ℃) improved the ratio of glucose to 5-HMF, which was a main inhibiting factor for the cell growth. Indeed, the recombinant E. coil exhibited better performance on the hydrolysate generated at 215 ℃ and accumulated P(3HB) up to 42 wt%, which was the same as the case of the same concentration of analytical grade glucose. The result indicated that the ruthenium-mediated cellulose hydrolysis has a potency as a useful biorefinery process for production of bio-based plastic from cellulosic biomass

Synthesis of sugar alcohols by hydrolytic hydrogenation of cellulose over supported metal catalysts

Cellulose is converted into sorbitol and related sugar compounds over water-tolerant and durable carbon-supported Pt catalysts under aqueous hydrogenation conditions. Pre-treatment of cellulose with ball-milling effectively reduces the crystallinity and particle size of cellulose, which results in high conversion of cellulose to sorbitol and mannitol. The selectivity of sorbitol increases by using Cl-free metal precursors in the catalyst preparation as residual Cl on the catalysts promotes the side-reactions. The transformation of cellulose to sorbitol consists of the hydrolysis of cellulose to glucose via water-soluble oligosaccharides and the successive hydrogenation of glucose to sorbitol. The hydrolysis of cellulose is the rate-determining step, and the Pt catalysts promote both the hydrolysis and the hydrogenation steps

Electronic Effect of Ruthenium Nanoparticles on Efficient Reductive Amination of Carbonyl Compounds

Highly selective synthesis of primary amines over heterogeneous catalysts is still a challenge for the chemical industry. Ruthenium nanoparticles supported on Nb₂O₅ act as a highly selective and reusable heterogeneous catalyst for the low-temperature reductive amination of various carbonyl compounds that contain reduction-sensitive functional groups such as heterocycles and halogens with NH₃ and H₂ and prevent the formation of secondary amines and undesired hydrogenated byproducts. The selective catalysis of these materials is likely attributable to the weak electron-donating capability of Ru particles on the Nb₂O₅ surface. The combination of this catalyst and homogeneous Ru systems was used to synthesize 2,5-bis­(aminomethyl)­furan, a monomer for aramid production, from 5-(hydroxymethyl)­furfural without a complex mixture of imine byproducts