Efficient Epimerization of Aldoses Using Layered Niobium Molybdates

Takagaki, Atsushi; Furusato, Shogo; Kikuchi, Ryuji; Oyama, S. Ted

doi:10.1002/cssc.201501093

Cited by 29 publications

(52 citation statements)

References 42 publications

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“…For instance non-acidic LiNbMoO 6 and strongly acidic HNbMoO 6 efficiently catalyze epimerization of glucose to mannose without any isomer formation. 20 In contrast, glucose isomerization into fructose via an intramolecular 1,2-hydride shift mechanism with Lewis acid catalysts such as Sn-β zeolites can be very efficient giving a 55% glucose conversion and a 32% yield of fructose in water at 110°C. 21 Besides fructose, an epimer -mannose -was also formed.…”

mentioning

confidence: 99%

Aldose to ketose interconversion: galactose and arabinose isomerization over heterogeneous catalysts

Murzin

Murzina

Aho

et al. 2017

Catal. Sci. Technol.

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Isomerization of glucose, galactose and arabinose to corresponding keto-sugars was studied in the present work over a range of heterogeneous catalysts. Magnesium aluminates with different ratios between oxides resulting in materials with a Mg/Al ratio from 0.2 to 0.9 were prepared, characterized and evaluated in terms of their catalytic behavior. The catalyst with a Mg/Al ratio close to hydrotalcites was the most efficient considering activity, selectivity and stability. The sugar structure was shown to have a minor influence on catalytic activity and selectivity.

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mentioning

confidence: 99%

Aldose to ketose interconversion: galactose and arabinose isomerization over heterogeneous catalysts

Murzin

Murzina

Aho

et al. 2017

Catal. Sci. Technol.

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“…The total sugar yields increased with milling time ( Figure 6). [50] The product distributions werem aintained from the beginning of ball milling,w hereas the total yields increased monotonically.T his suggests that short-chain oligomers were not depolymerized into smaller molecules. Mannose was formed because of the selective epimerizationo fg lucose over HNbMoO 6 ,a sw e recently reported.…”

Section: Characterization Of Mixed Powdersa Fter Ball Millingmentioning

confidence: 99%

“…Mannose was formed because of the selective epimerizationo fg lucose over HNbMoO 6 ,a sw e recently reported. [50] The product distributions werem aintained from the beginning of ball milling,w hereas the total yields increased monotonically.T his suggests that short-chain oligomers were not depolymerized into smaller molecules. In other words, most of the resultant water-soluble sugars were not produced by successive degradation of oligosaccharides but by random andd irect decomposition of cellulose.…”

Section: Mechanochemical Depolymerization Of Cellulose In the Presencmentioning

confidence: 99%

Mechanochemical Decomposition of Crystalline Cellulose in the Presence of Protonated Layered Niobium Molybdate Solid Acid Catalyst

et al. 2018

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Direct depolymerization of crystalline cellulose into water-soluble sugars by solvent-free ball milling was examined in the presence of a strongly acidic layered metal oxide, HNbMoO , resulting in full conversion with 72 % yield of water-soluble sugars. Measurements by C cross-polarization magic angle spinning NMR spectroscopy and X-ray diffraction revealed that amorphization of cellulose occurred rapidly within 10 min. Scanning electron microscopy equipped with an energy dispersive X-ray indicated that the substrate and the catalyst were well mixed during milling. The time course of the product distribution showed that most of the resultant water-soluble sugars were produced not by successive degradation of oligosaccharides but by direct depolymerization of cellulose chains. The products included glucose, mannose, and cello-oligomers, as well as anhydrosugars. Addition of small amounts of polar solvents increased the sugar yield, whereas further addition of water decreased the selectivity to anhydrosugars. Calculations of the mechanical energy required for the ball-milling process showed that 0.02 % was utilized for the chemical transformation under the conditions examined in this study.

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“…have demonstrated that Mo‐based polyoxometalates are stabilized by electrostatic interaction with heteroatoms . Niobium‐modified layered LiNbMoO 6 and HNbMoO 6 have been shown to be stable in the epimerization of glucose without the leaching of Mo species . Although molybdenum‐based polyoxometalates with Keggin structure can epimerize glucose to mannose efficiently, the synthetic processes of Mo‐based polyoxometalates are complex.…”

Section: Introductionmentioning

confidence: 99%

Efficient Epimerization of Glucose to Mannose over Molybdenum‐Based Catalyst in Aqueous Media

Liu

Zhang

et al. 2020

ChemistrySelect

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Herein, the high activity and selectivity of activated carbonsupported molybdenum oxide catalysts (Mo/AC) in the epimerization of glucose to mannose is described. The catalysts afforded near-equilibrium glucose conversion (29.2 %) and selectivity (94.5 %) toward mannose in the epimerization of glucose. The catalysts were characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. It was found that the Mo/AC catalysts were mainly composed of highly dispersed MoO 2 and MoO 3 species. Compared to the soluble MoO 3 catalyst, Mo/AC showed higher stability and better catalytic performances in the epimerization of glucose to mannose. Further, the deactivation of Mo/AC catalysts was attributed to the leaching of molybdenum oxides. Isotope labeling experiments revealed that the deuterium atom at the C-1 position of mannose is formed by glucose-D2 epimerization.

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Efficient Epimerization of Aldoses Using Layered Niobium Molybdates

Cited by 29 publications

References 42 publications

Aldose to ketose interconversion: galactose and arabinose isomerization over heterogeneous catalysts

Aldose to ketose interconversion: galactose and arabinose isomerization over heterogeneous catalysts

Mechanochemical Decomposition of Crystalline Cellulose in the Presence of Protonated Layered Niobium Molybdate Solid Acid Catalyst

Efficient Epimerization of Glucose to Mannose over Molybdenum‐Based Catalyst in Aqueous Media

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