Cooperative Acid‐Base Sites of Solid Ba‐Zr Mixed Oxide Catalyst for Efficient Isomerization of Glucose to Fructose in Aqueous Medium

Abstract

Efficient and highly selective isomerization of glucose to fructose was achieved by using the inexpensive Ba−Zr mixed metal oxide catalyst. Catalyst was prepared by varying Ba−Zr ratios using co‐precipitation method. Various phases formed, planes exposed, morphology, elemental composition and particle size, basic site density and strength, oxidation state of elements were well studied by using various characterization techniques. The XRD analysis clearly indicates the presence of Ba+2 and Zr+4 in the form of BaO, ZrO2 and BaZrO3 phases. The SEM and HR‐TEM images indicate that, Ba−Zr (2 : 1) catalyst prepared showed uniform morphology with spherical and rod‐shaped particles ranging from 300 to 600 nm. Under the optimized reaction conditions Ba−Zr (2 : 1) catalyst exhibited excellent results in terms of 57 % of glucose conversion with 89 % selective formation of glucose. The presence of both acidic as well as basic sites play vital roles in activating the substrate molecules to selectively yield fructose. Ba−Zr (2 : 1) catalyst showed excellent recyclability performance up to four recycles.

Toward Understanding Base-Catalyzed Isomerization of Saccharides

“…It is noteworthy that isomerization in an organic or an aqueous–organic solvents resulted for most of solid bases in worse isomerization rates and yields compared to aqueous phase. Thus, H 2 O-DMSO, ,− H 2 O-THF (THF = tetrahydrofuran), H 2 O-DMF, , H 2 O-DMA (DMA = dimethylacetamide), H 2 O-sulfolane, H 2 O-acetone, H 2 O-methanol, , and H 2 O-ethanol, mixtures were exploited. In addition, pure DMA, DMF, ,,, DMSO, , methanol, ,,, ethanol, ,,, 1-propanol, iso-propanol, , 1-butanol, 2-butanol, γ-valerolactone (GVL), toluene, and sulfolane were tested.…”

Highly Selective Isomerization of Glucose to Fructose through a Biphasic and Recyclable Mimetic Enzyme Catalyst

“…[17] Recently, some heterogeneous catalysts have been attracted owing to the advantages of reusability and easy separation from the reaction system. Many solid base catalysts such as metal oxides, [18][19][20] solid organic amines polymer [21][22] and mesoporous molecular sieves [23][24] were used as catalysts for isomerization of glucose. Chadwick et al investigated the isomerization of glucose catalyzed by magnesium doped NaY molecular sieves and found that although the conversion of glucose increased with the increase of magnesium content, the selectivity of fructose significantly decreased, the 44.6 % conversion of glucose with 72.7 % selectivity of fructose was reached in the 10 wt% Mg-impregnated NaY catalytic system at 100 °C after 2 h. [25] A natural mineral bentonite was used as catalyst to obtain 39.2 % yield and 86.3 % selective of fructose in high catalyst load of 167 wt% at 110 °C and 60 min.…”

“…Recently, some heterogeneous catalysts have been attracted owing to the advantages of reusability and easy separation from the reaction system. Many solid base catalysts such as metal oxides, [18–20] solid organic amines polymer [21–22] and mesoporous molecular sieves [23–24] were used as catalysts for isomerization of glucose. Chadwick et al.…”

Enhanced conversion of glucose to fructose over naturalattapulgite catalyst promoted by CeO2 in water

“…Meanwhile, the process is high cost and was restricted by the lower stability and the short life cycle of enzyme. Therefore, various efforts have been transferred to the chemical routes on glucose isomerization into fructose by screening effective catalysts [15–22] . Some homogeneous catalysts such as alkali hydroxides and organic amines have been applied for glucose isomerization in water and the yield of fructose was achieved 10–40 % with the selectivity of 40–76 %, however, these homogeneous catalysts were separated difficultly from the reaction products accompanying with strong irritant odors.…”

“…Therefore, various efforts have been transferred to the chemical routes on glucose isomerization into fructose by screening effective catalysts. [15][16][17][18][19][20][21][22] Some homogeneous catalysts such as alkali hydroxides and organic amines have been applied for glucose isomerization in water and the yield of fructose was achieved 10-40 % with the selectivity of 40-76 %, however, these homogeneous catalysts were separated difficultly from the reaction products accompanying with strong irritant odors. Therefore, it is essential to adopt the heterogeneous catalysts for the fructose production.…”