The kinetics of the molybdate-catalysed epimerization of D-glucose and D-mannose in aqueous solutions

Cybulski, Andrzej; Kuster, Bfm Ben; Marin, Gbmm Guy

doi:10.1016/0304-5102(91)80063-9

Cited by 17 publications

(11 citation statements)

References 23 publications

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“…Comparison of these calculated values with other apparent activation barriers reported in the literature using other catalytic systems evidences that the Ea,epim achieved here for the MOF-type catalysts are lower than those reported for glucose epimerization using molybdate catalysts (126 kJ/mol for ammonium heptamolybdate 40 and 97 kJ/mol for molybdenum-based polyoxometalates 41 ) and that the Ea,isom values are similar for the glucose isomerization catalyzed by Sn-Beta (93 kJ/mol). 15,42…”

Section: Figure 5 Kinetic Profiles With Glucose Conversion (Grey Squares)supporting

confidence: 73%

Unraveling the Reaction Mechanism and Active Sites of Metal–Organic Frameworks for Glucose Transformations in Water: Experimental and Theoretical Studies

Rojas‐Buzo

Corma

Boronat

et al. 2020

ACS Sustainable Chem. Eng.

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The catalytic performance of two different metalorganic frameworks, UiO-66 and MOF-808, containing Lewis acid active sites has been evaluated for the transformation of glucose in water, and compared with that of analogous Lewis acid Zr-Beta zeolite. While fructose is the main product obtained on Zr-Beta, the mannose production increases when using Zr-MOFs as catalysts. Kinetic studies reveal a lower activation energy barrier for glucose epimerization to mannose when using Zr-MOF catalysts (83-88 and 100 kJ/mol for glucose epimerization and isomerization, respectively). A 13 C NMR study using 13 C1-labelled glucose allows confirming that on Zr-MOF catalysts mannose is exclusively formed following the glucose epimerization route through 1,2intramolecular carbon shift, whereas the two step glucose → fructose → mannose isomerization via 1,2-intramolecular proton shifts is the preferred pathway on Zr-Beta. A computational study reveals a different mode of adsorption of deprotonated glucose on Zr-MOFs that allows decreasing the activation barrier for the 1,2intramolecular carbon shift. The combination of spectroscopic, kinetic and theoretical studies allows unraveling the nature of the metal sites in Zr-MOFs and Zr-Beta catalysts and to propose a structure-activity relationship between the different Lewis acid sites and the glucose transformation reactions. The results presented here could permit new rationalized MOF catalyst designs with the specific active sites to facilitate particular reaction mechanisms.

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Section: Figure 5 Kinetic Profiles With Glucose Conversion (Grey Squares)supporting

confidence: 73%

Unraveling the Reaction Mechanism and Active Sites of Metal–Organic Frameworks for Glucose Transformations in Water: Experimental and Theoretical Studies

Rojas‐Buzo

Corma

Boronat

et al. 2020

ACS Sustainable Chem. Eng.

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“…Figure b also shows Arrhenius plots for the epimerization. The apparent activation energy, E a was 73 kJ mol −1 , which is much lower than that of a homogeneous molybdate catalyst (126 kJ mol −1 ) and Mo‐based polyoxometalates (96–99 kJ mol −1 ), and comparable to that of Sn‐beta zeolite in methanol (70 kJ mol −1 ) . The reaction mechanism is similar to Scheme because Mo is crucial for the activity.…”

Section: Methodsmentioning

confidence: 79%

“…This carbon rearrangement reaction is known as the Bílik reaction, first discovered over homogeneous Mo‐based catalysts in acidic aqueous solution where a binuclear molybdate–glucose complex was proposed as the transition state (Scheme ) . Homogeneous molybdate catalysts including molybdic acid and heptamolybdate can catalyze the glucose–mannose epimerization as well as the xylose–lyxose epimerization in acidic aqueous solutions . Recently, a polymer‐supported Mo catalyst and Mo‐based polyoxometalates were found to exhibit high activity for epimerization of carbohydrates in water according to the same reaction mechanism …”

Section: Methodsmentioning

confidence: 99%

Efficient Epimerization of Aldoses Using Layered Niobium Molybdates

et al. 2015

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Both non-acidic LiNbMoO6 and strongly acidic HNbMoO6 efficiently catalyze the epimerization of sugars including glucose, mannose, xylose, and arabinose in water. The reactions over these oxides reached almost equilibrium within a few hours where yields of corresponding epimers from glucose, xylose, and arabinose were 24-29%. The layered mixed oxides functioned as heterogeneous catalysts and could be reused without loss of activity, whereas bulk molybdenum oxide MoO3 was completely dissolved during the reaction. A (13)C substitution experiment showed that the reaction proceeds through a 1,2-rearrangement mechanism. The surface Mo octahedra were responsible for the activity. The layered HNbMoO6 could also afford mannose from cellobiose through hydrolysis and successive epimerization.

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“…In an extensive investigation, Bilik and co-workers (Bilik, 1972;Bilik and Caplovic, 1973;Bilik and Stancovik, 1973;Bilik et al, 1975;Bílik et al, 1978aBílik et al, ,1978bBilik and Petrus, 1978;Bilik and Knezek, 1990;Cybulsk et al, 1991) reported homogeneous molybdate ion based catalyst for the epimerization of aldopentose and aldohexoses. Tanase et al (1988) also reported the epimerization of glucose catalyzed by Fig.…”

Section: Carbohydrate Conversion Reactions: Isomerization Epimerizatmentioning

confidence: 96%

Multiscale molecular modeling can be an effective tool to aid the development of biomass conversion technology: A perspective

Mushrif

Vasudevan

Krishnamurthy

et al. 2015

Chemical Engineering Science

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The kinetics of the molybdate-catalysed epimerization of D-glucose and D-mannose in aqueous solutions

Cited by 17 publications

References 23 publications

Unraveling the Reaction Mechanism and Active Sites of Metal–Organic Frameworks for Glucose Transformations in Water: Experimental and Theoretical Studies

Unraveling the Reaction Mechanism and Active Sites of Metal–Organic Frameworks for Glucose Transformations in Water: Experimental and Theoretical Studies

Efficient Epimerization of Aldoses Using Layered Niobium Molybdates

Multiscale molecular modeling can be an effective tool to aid the development of biomass conversion technology: A perspective

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