Rearrangement of glucose to mannose catalysed by polymer-supported Mo catalysts in the liquid phase

Catalytic Isomerization of Biomass‐Derived Aldoses: A Review

“…[99,110] Nevertheless, the catalyst can be reoxidized upon treatment with dilute H 2 O 2 solution. [110,112] Lewis acids catalyze epimerization, but the selectivityfor epimeric aldosei sl ow comparedt ot hat of the ketose (Table 3). Bermejo-Deval et al suggest that glucose epimerization into mannoseo ver Sn-b takes place by two consecutiveh ydrogen shifts (Figure 12 b).…”

“…As low decrease in catalytic activity has been observed mostly because of leaching of the active species into the liquid phase. [110] Additionally,h eptamolybdate exchanged on quaternary ammonia modifiedS BA-15-type mesoporouss ilica exhibits good activity and stability. [111] Ta kagaki et al have recently demonstrated the catalytic activity of the layered niobium molybdates LiNbMoO 6 and HNbMoO 6 .T he latter is also efficient for the one-pot hydrolysis-epimerization of cellobiose, which leads to an equilibrium mixtureo fg lucose and mannose.…”

Enhancing tungsten oxide/SBA-15 catalysts for hydrolysis of cellobiose through doping ZrO2

“…It is interesting to note that the mannose yield on these tungstate rich catalysts is significantly higher than those on the Brønsted acid type catalysts, but is similar to those on the supported molybdate catalysts [54,55]. It has been reported that molybdate dimmer could adsorb glucose through interaction with the hydroxyl groups connecting to C1-C4 carbon atoms and facilitate the forming C1 C3 bond at the expense of breaking the C2 C3 bond, leading to the formation of mannose [56]. Since Mo and W are the elements of the same group, one may expect that the tungstate dimmers formed on the Zr stabilized WO 3 tiny clusters on WZr/SBA-15 catalysts are able to catalyze the isomerization of glucose to mannose in a similar way as that bas been proposed on the molybdate catalyst.…”

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

“…Furthermore, the selectivity of mannose reduces owing to the leaching of Na + ions, which makes it necessary to develop novel highly efficient catalysts to epimerize glucose to mannose selectively. It has been shown that molybdate catalysts can epimerize glucose to mannose almost without any by‐products . Additionally, acidic pH of solution has been found to be vital to epimerization, and the selectivity is close to 100 % without side reactions.…”

“…Additionally, acidic pH of solution has been found to be vital to epimerization, and the selectivity is close to 100 % without side reactions. However, as molybdates dissolve in water, it is crucial to develop a stable heterogeneous Mo‐based catalyst for this transformation . Lari et al.…”