Isomerization of glucose into fructose in the presence of cation-exchanged zeolites and hydrotalcites

Catalytic Isomerization of Biomass‐Derived Aldoses: A Review

“…In this respect, solid catalysts are beneficial owing to facile catalysts eparation and recycling. Materialss uch as hydrotalcites, [30][31][32][33]39] immobilized amines, [34] zeolites in alkaline-exchange form, [30,40] mesoporous ordered molecular sieves of the M41S family, [41] zirconium carbonate, [42] and anion-exchanged resins [43] have been reported as efficient solid base catalysts. In the interest of productivity, the experiments are conducted at elevated temperatures, thoughs accharides, especially ketoses, are not stable under harsh conditions.…”

“…[40] The catalytic activity decreases in ar ow: NaA > NaX > NaY,t hat is, lower Si/Al ratios provideh igher concentrations of basic sites and greater activity. [30,40] Considering the exchangedc ation, the following series of activity is observed for the isomerizationo fg lucose: Ca 2 + < Ba 2 + < Li + < Na + < K + < Cs + . [30] Interestingly,Azeolite outperforms Xzeolite and Yzeolite in terms of catalytic activity,a nd as mall pore aperture of 4.1 d oes not seem to cause diffusionali ssues.…”

“…[30,40] Considering the exchangedc ation, the following series of activity is observed for the isomerizationo fg lucose: Ca 2 + < Ba 2 + < Li + < Na + < K + < Cs + . [30] Interestingly,Azeolite outperforms Xzeolite and Yzeolite in terms of catalytic activity,a nd as mall pore aperture of 4.1 d oes not seem to cause diffusionali ssues. [30] An obstacle for the application of sodium-exchanged zeolites is ratherl eaching of sodium into the aqueous medium.…”

Green Chemicals from d-glucose: Systematic Studies on Catalytic Effects of Inorganic Salts on the Chemo-Selectivity and Yield in Aqueous Solutions

“…It is well possible that the salt promotes the isomerisation of D-glucose to D-mannose and D-fructose. This isomerisation reaction is well known to be catalysed by solids (cation ion exchange resins, hydrotalcites and metal oxides such as ZrO 2 and TiO 2 ) and involves an 1,2-enediol as the intermediate [10,[22][23][24]. The D-fructose and D-mannose formed in the isomerisation reaction are not inert and also known to react to, among others, HMF and levulinic acid [1].…”

Conversion of Carbohydrates into Platform Chemicals Catalyzed by Alkaline Ionic Liquids

“…An alkaline catalyst can promote glucose to be isomerized to fructose, which is known as the Lobry-de Bruyn-van Ekenstein transformation. Thus, [TMG]BF 4 is clearly an effective catalyst, regarded as a key step in the conversion of glucose into 5-HMF [38][39][40]. On the other hand, compared to glucopyranose (α-D-glucopyranose and β-D-glucopyranose), the structure of glucofuranose (α-D-glucofuranose and β-D-glucofuranose) is more suitable for the synthesis of 5-HMF.…”