Catalytic Deoxygenation of Xylitol to Renewable Chemicals: Advances on Catalyst Design and Mechanistic Studies

Abstract

Xylitol is commonly known as one of the top platform intermediates for biomass conversion. Catalytic deoxygenation of xylitol provides an atomic and energetic efficient way to produce a variety of renewable chemicals including ethylene glycol, 1,2‐propanediol, lactic acid and 1,4‐anhydroxylitol. Despite a few initial attempts in converting xylitol into those products, improving catalyst selectivity towards C−O and C−C cleavage reactions remains a grand challenge in this area. To our best knowledge, there is lack of comprehensive review to summarize the most recent advances on catalyst design and mechanisms in deoxygenation of xylitol, offering important perspective into future development of xylitol transformation technologies. Therefore, in this mini‐review, we have critically discussed the conversion routes involved in xylitol deoxygenation over solid catalyst materials, the nanostructures of supported metal catalysts for C−H, C−C and C−O bond cleavage reactions, and mechanistic investigation for xylitol conversion. The outcome of this work provides new insights into rational design of effective deoxygenation catalyst materials for upgrading of xylitol and future process development in converting hemicellulosic biomass.

Hydrodeoxygenation of potential platform chemicals derived from biomass to fuels and chemicals

“…42,43 Bindwal and Vaidya reported the hydrogenolysis of levoglucosan over a Ru/C catalyst in water as a solvent. 44 The main products were 1,2-propanediol and ethylene glycol with a combined yield of 35%-C (94.8% conversion) at 413 K. These glycols can also be produced by the hydrogenolysis of various sugars and sugar alcohols such as cellulose, 45,46 sorbitol, [47][48][49] xylitol, 50 and glycerol. 51,52 The combined yields Fig.…”

Synthesis of Secondary Monoalcohols from Terminal Vicinal Alcohols over Silica-Supported Rhenium-Modified Ruthenium Catalyst

“…Traditionally, the petrochemical refinery has been the major route for the production of chemicals and fuels in human civilization. To overcome global warming and the depletion of fossil resources, green technology using biomass and biobased solid wastes as raw material for organic chemicals, so-called biorefinery, has been developed widely, since biomass is the only carbon-neutral and renewable source of organic carbon. , Due to the intrinsic properties (the complex mixture of polymers with various minor components) of raw biomass, the use of “platform chemicals”, which can be readily synthesized in pure form from biomass, as intermediates is a typical approach to synthesizing useful chemicals from biomass. , Sugar alcohols, polyols with an O/C ratio of 1, are typical platform chemicals and produced from these resources such as glycerol from the manufacturing process of biodiesel fuel, erythritol from sugars by fermentation, xylitol from hemicellulose by hydrolytic hydrogenation, and sorbitol from sugars or cellulose by (hydrolytic) hydrogenation . Many other polyols can also be produced from biomass via reduction of sugars or sugar-derived platform chemicals such as 1,2-propanediol from sugars, pentanediols from furfural, , 1,4-pentanediol from levulinic acid, and hexanetriols/hexanetetraols from sugar derivatives .…”

Ru on N‐doped Carbon for the Selective Hydrogenolysis of Sugars and Sugar Alcohols

“…[52] For ACÀ HNO 3 the ratio of O/C on the surface increases from 5.2 • 10 À 2 (AC) to 13.0 • 10 À 2 and nitrogen is introduced with a ratio of N/C of 1. ChemCatChem sp 3 -hybridized carbon on the surface, implying that the acid treatment creates defects in the aromatic carbon structure decreasing the degree of graphitization (Figure 3b). In the N 1s region, two signals occur which are assigned to NÀ O species such as in nitro or nitroso groups (405.7 eV) [53] and NÀ C species such as pyridinic, pyrollic and graphitic nitrogen (400.2 eV) (Figure 3c).…”

“…The production of glycols, used as monomers in the chemical industry, offers the possibility to substitute fossil by renewable raw materials [1–2] . Sugar alcohols such as the hemicellulose derived platform molecule xylitol (XYL) can be used as feedstock [3] . The conversion to ethylene and propylene glycol (EG and PG) involves many reaction mechanisms such as metal catalyzed dehydrogenation and hydrogenation or base promoted retro‐aldol splitting (Scheme 1).…”

“…[1][2] Sugar alcohols such as the hemicellulose derived platform molecule xylitol (XYL) can be used as feedstock. [3] The conversion to ethylene and propylene glycol (EG and PG) involves many reaction mechanisms such as metal catalyzed dehydrogenation and hydrogenation or base promoted retroaldol splitting (Scheme 1). [4][5][6][7] Glycerol (GLY) is formed in significant amounts as by-product as well as the side product lactic acid (LA).…”