Regulating the Alkalinity of Carbon Nitride by Magnesium Doping to Boost the Selective Isomerization of Glucose to Fructose

Abstract

Brønsted base catalyzed isomerization of glucose toward fructose is on the rise due to the high value and versatility of fructose in biorefinery. Herein, we report the discovery of alkali- and alkaline-earth-metal-doped carbon nitride (C3N4) as base catalysts for the selective isomerization of glucose to fructose. The characterizations proved that introducing a small quantity of alkali and alkaline-earth metals into C3N4 can remarkably improve the amount of strong basic sites. Among the tested materials, Mg-doped C3N4 afforded an excellent fructose yield (>32%) and selectivity (>84%) from a high loading (10 wt %) of glucose in water at 80 °C with the lowest apparent activation energy (107 kJ mol–1), far exceeding that of the pristine C3N4 material. Although more efforts are required to improve the reusability, the proof of strong alkalinity and superior catalytic performance should greatly extend the applications of metal-doped C3N4 materials.

The functional and synergetic optimization of the thermal-catalytic system for the selective oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran: a review

“…As shown in Fig. 1, the conversion of cellulose to HMF consists of three steps: hydrolysis of cellulose into glucose, 9–12 isomerization of glucose into fructose, 13 and the dehydration of fructose into HMF. 14…”

“…As shown in Fig. 1, the conversion of cellulose to HMF consists of three steps: hydrolysis of cellulose into glucose, [9][10][11][12] isomerization of glucose into fructose, 13 and the dehydration of fructose into HMF. 14 As one of the "top ten important bio-based chemicals that can be converted into various value-added products" recognized by the U.S. Department of Energy, HMF can be used to synthesize precursors for fuels and medical drugs as well as other platform compounds, such as 2,5-furandicarboxylic acid (FDCA), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) and 5-formyl-2-furancarboxylic acid (FFCA).…”

Revealing the contributions of homogeneous and heterogeneous catalysis to isomerization of d-glucose into d-fructose in the presence of basic salts with low solubility

“…15 Solid bases 16 and solid Lewis acids 17 exhibit comparable catalytic activity for the isomerization though the Lewis acids catalyze co-formation of D-mannose in somewhat higher amounts. A broad range of solid bases exhibit catalytic activity for the isomerization, which includes MgO 14,18,19 and other alkaline earth metal (hydr)oxides, 20 MgO-doped ordered mesoporous carbon, 21 Mg-Al hydrotalcites, 14,15,18,[22][23][24][25][26][27][28][29][30] Mg-or Ca-impregnated or exchanged zeolites, [31][32][33][34][35] attapulgite, 36,37 MgO-Nb phosphate, 38 Mg-doped carbon nitride, 39 Mg-containing titanosilicates, 40 CaO-ZrO 2 , 41 MgO-ZrO 2 , 42 MgO/biochar, 43 CaO-Al 2 O 3 , 44 CaO-MgO, 45 CaO/ C, 46 alkaline earth metal titanates, 47 soluble amines [48][49][50][51][52][53][54][55]…”

Hantzsch Reaction using Copper Nitrate Hydroxide- Containing Mesoporous Silica Nanoparticle with C 3 N 4 Framework as A Novel Powerful and Reusable Catalyst

“…Owing to its promising features, g-C 3 N 4 and its composites are applied in a variety of photocatalytic applications (49). So far, g-C 3 N 4 has been utilized as a catalyst or catalyst support in various organic reactions (50)(51)(52)(53)(54)(55). However, the practical application of g-C 3 N 4 is limited by its low surface area, insu cient light absorption, reduction potential, inappropriate rapid recombination, and large diffusion resistance of charges.…”