Controlling Transformation of Sorbitol into 1-Hexanol over Ru-MoO_x/Mo₂C Catalyst via Aqueous-Phase Hydrodeoxygenation

Abstract

Higher alcohols are important monohydric alcohols category of synthetic chemicals and fuels. Currently, research efforts in this catalytic synthesis have been devoted to providing desirable selectivity to specific higher alcohols. In this work, for the first time, the aqueous-phase hydrodeoxygenation of sorbitol derived from biomass was proposed to efficiently synthesize renewable 1-hexanol over a multifunctional Ru-MoO x /Mo 2 C catalyst in a continuous-flow tubular reactor. Compared with molybdenum nitride, phosphide, sulfide, and oxide catalysts, molybdenum carbide displayed promising catalytic performance in the selective transformation of sorbitol into 1-hexanol, representing the feasibility of selectively controlling the C−O bond cleavage and preserving the original carbon chain. Studies in catalyst characterization revealed that the synergism of Ru and Mo 2 C was the key to manipulate the main product selectivity between 1-hexanol and 1-hexane, while the 1hexanol selectivity was concurrently promoted by the presence of MoO x . The highest yield (28.7%) of 1-hexanol was achieved at 523 K under 6.0 MPa of hydrogen pressure. The present catalyst system was equally applicable to the selective hydrogenolysis of other sugar polyols such as xylitol, erythritol, glycerin, and ethylene glycol into the corresponding 1-pentanol, 1-butanol, 1-propanol, and ethanol. Thus, this catalytic strategy creates new opportunities for producing high value-added higher alcohols from sugar polyols over molybdenum carbide materials.

Highly Efficient Iridium–Iron–Molybdenum Catalysts Condensed on Boron Nitride for Biomass-Derived Diols’ Hydrogenolysis to Secondary Monoalcohols

“…Secondary alcohols with high yield were effectively synthesized over Ir–Fe 0.13 –Mo 0.08 /BN (20 wt % Ir) at a much shorter reaction time than previous Ir–Fe/support (support = BN or rutile) catalysts. , Importantly, 2,3-butanediol (2,3-BuD) was obtained with a higher yield (35.8%) at a short reaction time ( t = 30 h, m Ir = 0.01 g) over the Ir–Fe 0.13 –Mo 0.08 /BN (20 wt % Ir) catalyst than our previous reports (≤32.3% yield, Ir = 5 wt %, Fe/Ir = 0.25, m Ir = 0.02 or 0.025 g, t = 72 or 96 h). , The high yield of 2-pentanol (2-PeOH, 75%) was obtained from 1,2-pentanediol at a short reaction time (14 h). This yield of 2-PeOH was quite higher than previous reports for 2-PeOH synthesis from biomass-derived sugar alcohols . As a limited case of 2-PeOH synthesis from biomass, a similar yield of 2-PeOH (71%) was reported from furfural over Co–Cu/Al 2 O 3 catalysts under severe conditions (515 K, 4.5 MPa H 2 , 12 h) …”

Conversion of Isosorbide Diacetate to 1,6-Diacetoxyhexane by a Combined Hetero-/Homogeneous Tandem Catalyst System

“…Mannitol made by the hydrogenation of fructose could presumably also be used. The low solubility of sorbitol in any solvent other than water presents a different challenge here and several earlier reports on the conversion of sorbitol focused on total HDO to alkanes. − A selective conversion of sorbitol to 1-hexanol in ∼30% yield is also possible . The conversion of sorbitol into a blend of hexane, 1-hexanol, and hexane-diols has also been demonstrated with a maximum yield of 1,6-hexanediol of 6%, , as well as the direct conversion of depolymerized cellulose to hexanols and alkanes .…”

“…48−53 A selective conversion of sorbitol to 1-hexanol in ∼30% yield is also possible. 54 The conversion of sorbitol into a blend of hexane, 1-hexanol, and hexane-diols has also been demonstrated with a maximum yield of 1,6-hexanediol of 6%, 55,56 as well as the direct conversion of depolymerized cellulose to hexanols and alkanes. 57 A complex product spectrum results from the (formal) Ru/C catalyzed hydrogenolysis of sorbitol and other sugar polyols in neutral and acidic aqueous media.…”

Review and Outlook on Regulation of Catalyst Activity, Selectivity, and Stability for Biomass Hydrodeoxygenation Reaction in an Aqueous Environment

“…Consequently, the concentrated sorbitol solution alters the product distribution, favoring the generation of 1-hexane. 55 Abusuek et al 56 investigated the hydrogenation of levulinic acid (LA) over Ru-containing catalysts, which used ZSM-5 as a support, for the generation of γ-valerolactone (GVL) in aqueous medium. The results showed that the support acidity and surface content of RuO 2 strongly influence the catalytic activity.…”

“…This process leads to increased concentration of the sorbitol solution on the catalyst bed, facilitating prolonged engagement between the reactants and the catalyst surface. Consequently, the concentrated sorbitol solution alters the product distribution, favoring the generation of 1-hexane …”