Acid sites characterization of niobium phosphate catalysts and their activity in fructose dehydration to 5-hydroxymethyl-2-furaldehyde

Armaroli, Tiziana; Busca, Guido; Carlini, Carlo; Giuttari, Mario; Galletti, Anna Maria Raspolli; Sbrana, Glauco

doi:10.1016/s1381-1169(99)00248-4

Cited by 200 publications

(127 citation statements)

References 39 publications

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“…900 cm -1 can be assigned to the same vibrational modes corresponding to the similar Raman features observed in the Raman spectra of these 54 The absorption observed at 1630 cm -1 corresponds to the HOH bending mode of the water present in the catalyst. Furthermore, new absorptions emerge upon acidic treatments which are also displayed in Table 3.…”

Section: Catalysts Characterizationsupporting

confidence: 55%

“…The respective asymmetric stretching modes are observed in the FT-IR spectrum at 1011 and 1149 cm -1 (see Table 3). It is worth to mention that Amaroli et al 54 have observed strong absorptions between 1040 and 1100 cm -1 in the IR spectra of niobate catalysts treated with phosphoric acid which were assigned to the O=P=O asymmetric stretching modes of phosphate or polyphosphate species.…”

Section: Catalysts Characterizationmentioning

confidence: 99%

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Synthesis, characterization and use of Nb2O5 based catalysts in producing biofuels by transesterification, esterification and pyrolysis

Brandão¹,

Quirino²,

Mello³

et al. 2009

J. Braz. Chem. Soc.

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2 O have been investigated as catalysts for the transesterification, esterification and pyrolysis of vegetable oils. The compounds were characterized by thermal analysis (DTA-TGA), spectroscopy (DRX, FT-IR and FT-Raman), surface area (BET) and the acidity (Ho) determined by n-butylamine titration using the Hammet´s indicator method. It was observed that after the acid treatment both the surface area and the acidity decreased as compared to the starting Nb 2 O 5 •xH 2 O. The only exception was a higher acidity verified when nitric acid was used. Among the catalyst investigated, the Nb 2 O 5 /H 3 PO 4 presented the highest activity in the alcoholysis of soybean oil with different mono-alcohols (methanol, ethanol, 2-propanol, n-butanol

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Section: Catalysts Characterizationsupporting

confidence: 55%

Section: Catalysts Characterizationmentioning

confidence: 99%

Synthesis, characterization and use of Nb2O5 based catalysts in producing biofuels by transesterification, esterification and pyrolysis

Brandão¹,

Quirino²,

Mello³

et al. 2009

J. Braz. Chem. Soc.

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“…Niobic acid (sample NBA) shows a major strong band centered at 586 cm −1 and a shoulder band at 933 cm −1 . This spectrum is consistent with the skeletal vibration previously reported for amorphous niobic acid [12,21,22]. The spectrum of niobium oxide crystals (sample NBO) exhibits two strong bands at 615 and 850 cm −1 .…”

Section: Catalysts Characterizationsupporting

confidence: 90%

Characterization and Catalytic Performance of Niobic Acid Dispersed over Titanium Silicalite

Prasetyoko

Ramli

Endud

et al. 2008

Advances in Materials Science and Engineering

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Niobic acid, Nb 2 O 5 ·nH 2 O, has been supported on the titanium silicalite by impregnation method. The obtained materials were characterized by X-ray diffraction, infrared, and ultra-violet-visible diffuse reflectance spectroscopy, temperature programmed reduction, pyridine adsorption, and field emission scanning electron microscopy techniques. It was demonstrated that the tetrahedral titanium species still retained after impregnation of niobic acid. The results revealed that niobium species interacted with hydroxyl groups on the surface of TS-1. The niobium species in the catalysts are predominantly polymerized niobium oxides species or bulk niobium oxide with the octahedral structure. All catalysts showed both Brønsted and Lewis acid sites. The catalysts have been tested for epoxidation of 1-octene with aqueous hydrogen peroxide. It was found that the presence of niobic acid in the catalysts enhanced the rate of the formation of epoxide at the initial reaction time. Diol as a side product was also observed due to the acidic properties of the catalysts.

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“…Scheme 2 summarizes the structures of Brönsted and Lewis acid sites over the tested catalysts. According to Scheme 2, the Lewis acid sites over NbP catalyst were assigned to coordinatively unsaturated Nb 5+ sites, whereas the Brönsted acid sites on NbP catalyst were attributed to either Nb-OH or P-OH sites [35]. Table 3 shows the effect of organic phase on xylose conversion and furfural yield over NbP catalysts.…”

Section: Scheme 1 Suggested Reaction Mechanism Of Xylose Dehydrationmentioning

confidence: 99%

Dehydration of xylose to furfural over niobium phosphate catalyst in biphasic solvent system

Pholjaroen

Wang

et al. 2013

Journal of Energy Chemistry

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Acid sites characterization of niobium phosphate catalysts and their activity in fructose dehydration to 5-hydroxymethyl-2-furaldehyde

Cited by 200 publications

References 39 publications

Synthesis, characterization and use of Nb2O5 based catalysts in producing biofuels by transesterification, esterification and pyrolysis

Synthesis, characterization and use of Nb2O5 based catalysts in producing biofuels by transesterification, esterification and pyrolysis

Characterization and Catalytic Performance of Niobic Acid Dispersed over Titanium Silicalite

Dehydration of xylose to furfural over niobium phosphate catalyst in biphasic solvent system

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