Controlled synthesis of Ru-single-atoms on ordered mesoporous phosphine polymers for microwave-assisted conversion of biomass-derived sugars to artificial sweeteners

Abstract

Atomically dispersed metal-single-atoms have become a frontier in solid catalysis due to their characteristics electronic properties. However, for biomass conversion employing metal-single-atoms as catalysts is rather challenging since it suffers...

Facile Hydrogenolysis of Sugars to 1,2-Glycols by Ru@PPh3/OPPh3 Confined Large-Pore Mesoporous Silica

“…The major peak as observed at 2.35 Å is clearly indicating Ru–P coordination as justified from a prior report that discloses atomic dispersion of Ru-single atom under the influence of phosphorus-based ligands . Additionally, reported phosphine ligands, i.e., ordered phosphine polymers, BINAP-POP, and other phosphine support, control the atomic dispersion of Ru due to its unique ligand effect, which is henceforth reflected in this research. Thus, based on the previous reports as well as from our experiments, it is indicated that better atomically dispersed single-atom ruthenium is formed in PPh 3 PO/PPh 3 P modified on the mesoporous silica host (Ru@SiP).…”

Recent Progress and Opportunity of Metal Single‐Atom Catalysts for Biomass Conversion Reactions

“…Ni SA as Lewis acid and the neighbouring pyridinic site as Lewis base promotes hydrogenation and is imperative as a stable catalyst. Modak et al [19] reported an interesting Ru single atom catalyst that shows catalytic transfer hydrogenation of xylose and glucose to xylitol and sorbitol respectively, in a microwave reactor involving a green and mild reaction protocol, avoiding the use of pressurized reactor. Importantly, Ru-SA on triphenylphosphinecontaining ordered mesoporous polymer has pronounced transfer hydrogenation activity than commercial Ru/C and Ru SA grafted on other polymers viz.…”

“…For example, Ru@PPhMesoSi is an excellent catalyst for the microwave synthesis of xylitol and sorbitol as important sugar substitutes from hydrogenation of xylose and glucose respectively. [19] On the contrary, Ru-nanoparticles [28] and other bimetallic nanoparticles [29] are inactive for xylose hydrogenation in the microwave, but is an active catalyst under the harsh condition in a Parr reactor (high T & P). Under such context, SACs have shown progressive attention in the upgradation of complex feedstocks like cellulose, hemicellulose, and lignin which are the rich sources of chemicals and fuels.…”

“…Although SACs are advantageous, but the stability of a single metal atom is subject to the design of effective support and suitable interactions [15] . SACs containing carbon, [16] oxides, [17] zeolite, [18] and ordered porous polymers [19] graphene [20] have advantages as support regarding their higher specific surface area, pore volume, and stability which may improve the interaction with single‐metal sites, as described by several researchers [21] . SACs are synthesized depending upon the methods, such as pyrolysis, sol‐gel, impregnation‐incipient precipitation, and atomic layer deposition, while stabilized by ionic or covalent interactions within the neighbouring groups.…”

“…Similarly, Ru single atoms supported over ordered polymers proved efficiency to narrow down the reaction conditions. For example, Ru@PPhMesoSi is an excellent catalyst for the microwave synthesis of xylitol and sorbitol as important sugar substitutes from hydrogenation of xylose and glucose respectively [19] . On the contrary, Ru‐nanoparticles [28] and other bimetallic nanoparticles [29] are inactive for xylose hydrogenation in the microwave, but is an active catalyst under the harsh condition in a Parr reactor (high T & P).…”