Niobium phosphotungstates: excellent solid acid catalysts for the dehydration of fructose to 5-hydroxymethylfurfural under mild conditions

Qiu, Guo; Wang, Xincheng; Huang, Chongpin; Li, Yingxia; Chen, Biaohua

doi:10.1039/c8ra05940c

Cited by 15 publications

(13 citation statements)

References 61 publications

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“…The Sn loading decreased, i.e., Sn 3d 3/2 was decomposed into two peaks located at 493.38 and 495.98 eV, respectively, demonstrating the presence of a small amount of Sn (II) oxide in the sample. According to the literature for magnetite Qiu et al, 2018), the main peaks at 36.18 and 38.28 eV shown in the W 4f spectrum corresponded to W 4f 7/2 and W 4f 5/2 (Figure 3B). The binding energies of W 4f 7/2 and W 4f 5/2 in Sn 0.1 PW and Sn 0.75 PW showed a blueshift and slight decrease, respectively, and were weaker than that of pure HPW likely due to the interaction of the metal ion Sn n+ (n 2,4) with the anionic Keggin structural unit (Zhao et al, 2015).…”

Section: Catalyst Characterizationsupporting

confidence: 56%

Catalytic Conversion of Starch to 5-Hydroxymethylfurfural by Tin Phosphotungstate

et al. 2021

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Heteropoly acids containing Brønsted and Lewis acids show excellent catalytic activity. Brønsted acids promote the depolymerization of polysaccharides (such as starch and cellulose) into glucose, while Lewis acids catalyze the conversion of glucose to 5-hydroxymethylfurfural (HMF). Designing stable Brønsted-Lewis acid-containing bifunctional heterogeneous catalysts is crucial for the efficient catalytic conversion of polysaccharides to HMF. In this study, a series of Brønsted -Lewis acid bifunctional catalysts (SnxPW, X = 0.10–0.75) were investigated for the conversion of cassava starch to HMF. The structure of the catalysts was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Pyridine Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The acid strength and acid capacity were also investigated. The effects of reaction time, temperature, catalyst concentration, and cassava starch concentration on the selectivity, conversion rate, and yield were examined. The results showed that, among the analyzed catalysts, Sn0.1PW presented the best ability under the test conditions for catalyzing the conversion of starch to HMF. At the optimized conditions of a reaction temperature of 160°C, a catalyst dosage of 0.50 mmol/gstarch, and a 1 h reaction time, the starch conversion rate was 90.61%, and the selectivity and yield of HMF were 59.77 and 54.12%, respectively. Our findings contribute to the development of HMF production by the dehydration of carbohydrates.

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Section: Catalyst Characterizationsupporting

confidence: 56%

Catalytic Conversion of Starch to 5-Hydroxymethylfurfural by Tin Phosphotungstate

et al. 2021

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“…Then, it can be noted that the system tested here with niobia treated at 100 • C for hour has one of the highest yields (13.7%) in a relatively short reaction time (two hours). Niobia-based catalysts [16,66,67] and supported WO 3 on zirconia [16,68] also demonstrated promising results. In a recent study, solid acid TiO 2 -SO 3 H showed a very high selectivity (71%) using low fructose concentration (0.1 mol L −1 ), 18 mg of catalyst at 140 • C for 1 h [26].…”

Section: Comparison With Other Catalysts For Aqueous Fructose Dehydra...mentioning

confidence: 96%

Dehydration of Fructose to 5-Hydroxymethylfurfural: Effects of Acidity and Porosity of Different Catalysts in the Conversion, Selectivity, and Yield

et al. 2021

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There is a demand for renewable resources, such as biomass, to produce compounds considered as platform molecules. This study deals with dehydration of fructose for the formation of 5-hydroxymethylfurfural (HMF), a feedstock molecule. Different catalysts (aluminosilicates, niobic acid, 12-tungstophosphoric acid—HPW, and supported HPW/Niobia) were studied for this reaction in an aqueous medium. The catalysts were characterized by XRD, FT-IR, N2 sorption at −196 °C and pyridine adsorption. It was evident that the nature of the sites (Brønsted and Lewis), strength, quantity and accessibility to the acidic sites are critical to the conversion and yield results. A synergic effect of acidity and mesoporous area are key factors affecting the activity and selectivity of the solid acids. Niobic acid (Nb2O5·nH2O) revealed the best efficiency (highest TON, yield, selectivity and conversion). It was determined that the optimum acidity strength of catalysts should be between 80 to 100 kJ mol−1, with about 0.20 to 0.30 mmol g−1 of acid sites, density about 1 site nm−2 and mesoporous area about 100 m2 g−1. These values fit well within the general order of the observed selectivity (i.e., Nb2O5 > HZSM-5 > 20%HPW/Nb2O5 > SiO2-Al2O3 > HY > HBEA).

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“…For the recycling of the catalyst, the humins were filtered out first, while the catalyst remained in the liquid phase and was recovered via liquid-liquid extraction (Figure 5 a). Hence, pseudo-liquid phase [47] (Table 2, entries 2-4), [41,48,49] of which Nb x H y PW [49] achieves the best catalytic results combining mild reaction conditions and good stability. For the hydrothermal synthesis of LA from different carbohydrate feedstocks (Table 2, entry 5), Kumar et al synthesized GaHPMo salts based on a sonochemical approach.…”

Section: Miscellaneous Saltsmentioning

confidence: 99%

“…Reproduced from Tao et al with permission from Elsevier [47]. (Table2, entries 2-4),[41,48,49] of which Nb x H y PW[49] achieves the best catalytic results combining mild reaction conditions and good stability. For the hydrothermal synthesis of LA from different carbohydrate feedstocks (Table2, entry 5), Kumar et al synthesized GaHPMo salts based on a sonochemical approach [50].…”

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confidence: 99%

Solidified and Immobilized Heteropolyacids for the Valorization of Lignocellulose

et al. 2022

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Heteropolyacids have been identified as promising for catalyzing the reaction types, hydration and dehydration, which play an important role in the valorization of lignocellulose. Not only do they possess adaptable Brønsted acidity, but they also show a redox multi functionality. To increase the industrial applicability of this promising class of catalysts and to enable recycling, many different approaches for immobilization (such as multiphasic catalysis or grafting) and solidification (such as salt formation) have been pursued in recent years. This review summarizes these efforts and highlights the studied acidcatalyzed lignocellulose conversions, trends and current challenges.

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Niobium phosphotungstates: excellent solid acid catalysts for the dehydration of fructose to 5-hydroxymethylfurfural under mild conditions

Abstract: A 5-HMF yield of 96.7% was obtained over an excellent heterogeneous catalyst NbPW-06 in DMSO at 80 °C.

Cited by 15 publications

References 61 publications

Catalytic Conversion of Starch to 5-Hydroxymethylfurfural by Tin Phosphotungstate

Catalytic Conversion of Starch to 5-Hydroxymethylfurfural by Tin Phosphotungstate

Dehydration of Fructose to 5-Hydroxymethylfurfural: Effects of Acidity and Porosity of Different Catalysts in the Conversion, Selectivity, and Yield

Solidified and Immobilized Heteropolyacids for the Valorization of Lignocellulose

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