Brønsted Acid Property of Alumina-Supported Niobium Oxide Calcined at High Temperatures: Characterization by Acid-Catalyzed Reactions and Spectroscopic Methods

Kitano, Tomoyuki; Shishido, Tetsuya; Teramura, Kentaro; Tanaka, Tsunehiro

doi:10.1021/jp3032429

Cited by 42 publications

(29 citation statements)

References 82 publications

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“…This means that Nb2O5 reacted with Al2O3 at the high temperatures. This trend was also reported by Shishido et al 11),13) . The BET surface area decreased as the calcination temperature was raised as summarized in Table 1.…”

Section: Effect Of Calcination Temperature Andsupporting

confidence: 87%

“…Zaki et al investigated the acidic properties of supported WO3 catalysts by pyridine adsorption and reported that strong Brønsted acid sites appeared on WO3/TiO2, whereas mainly Lewis acid sites existed on WO3/Al2O3 12) . Nb2O5/Al2O3 catalysts were reported to possess both Lewis acid sites and Brønsted acid sites 13) . At 250 in Fig.…”

Section: Dme Hydrolysis Over Supported Solid Acidmentioning

confidence: 99%

See 1 more Smart Citation

Steam Reforming of Dimethyl Ether over Composite Catalysts of Supported Transition Metal Oxides and Cu/ZnO/Al2O3

文人

昌平

隆司

2016

J. Jpn. Petrol. Inst.

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Section: Effect Of Calcination Temperature Andsupporting

confidence: 87%

Section: Dme Hydrolysis Over Supported Solid Acidmentioning

confidence: 99%

Steam Reforming of Dimethyl Ether over Composite Catalysts of Supported Transition Metal Oxides and Cu/ZnO/Al2O3

文人

昌平

隆司

2016

J. Jpn. Petrol. Inst.

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“…2) All of the NbO 6 units have the same cross-section. [23] On 16 wt % Nb 2 O 5 /Al 2 O 3 catalysts that were calcined at 1073 K and 1123 K, S 0 was comparable to S occupied . [24] The surface area decreases as the calcination temperature and Nb 2 O 5 loading increase.…”

Section: Physical Propertiesmentioning

confidence: 95%

“…[21][22][23] The activities of Nb 2 O 5 /Al 2 O 3 towards these reactions were proportional to its Brønsted acidity, thus indicating that these reactions occurred at the Brønsted acid sites on the Nb 2 O 5 /Al 2 O 3 catalysts. [21][22][23] The activities of Nb 2 O 5 /Al 2 O 3 towards these reactions were proportional to its Brønsted acidity, thus indicating that these reactions occurred at the Brønsted acid sites on the Nb 2 O 5 /Al 2 O 3 catalysts.…”

Section: Introductionmentioning

confidence: 97%

Characterization of Thermally Stable Brønsted Acid Sites on Alumina‐Supported Niobium Oxide after Calcination at High Temperatures

et al. 2013

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Thermally stable Brønsted acid sites were generated on alumina-supported niobium oxide (Nb2O5/Al2O3) by calcination at high temperatures, such as 1123 K. The results of structural characterization by using Fourier-transform infrared (FTIR) spectroscopy, TEM, scanning transmission electron microscopy (STEM), and energy-dispersive X-ray (EDX) analysis indicated that the Nb2O5 monolayer domains were highly dispersed over alumina at low Nb2O5 loadings, such as 5 wt%, and no Brønsted acid sites were presents. The coverage of Nb2O5 monolayer domains over Al2O3 increased with increasing Nb2O5 loading and almost-full coverage was obtained at a loading of 16 wt%. A sharp increase in the number of hydroxy groups, which acted as Brønsted acid sites, was observed at this loading level. The relationship between the acidic properties and the structure of the material suggested that the bridging hydroxy groups (Nb-O(H)-Nb), which were formed at the boundaries between the domains of the Nb2O5 monolayer, acted as thermally stable Brønsted acid sites.

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“…A niobic oxide monolayer with distorted octahedral NbO 6 units stabilized by an alumina surface exhibited Brønsted acidity after calcination at 1123 K toward organic reactions such as benzylation of anisole, cumene cracking, and α-pinene isomerization [38,39]. The Brønsted acid sites are probably generated at boundaries between two niobic oxide monolayer domains.…”

Section: New Catalytic Systemsmentioning

confidence: 99%

Mechanistic Studies of Solid Acids and Base‐Catalyzed Clean Technologies

Takagaki

Nishimura

Ebitani

2013

Heterogeneous Catalysts for Clean Technology

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IntroductionThe importance of solid acid and base catalysts in clean technologies has been recognized for a long time, and many books and reviews have been published since the text by Tanabe [1]. Tanabe et al.[2] revised their book in 1989, reviewing the definition and classification of solid acids and bases, determination of acidic and basic properties, and catalysis for isomerization, acylation, hydration of alkenes, methanol conversion, dehydration, dehydrogenation, esterification, hydrolysis, hydrocraking (hydrogenolysis), and oxidation reactions. The development of solid acid catalysts has been surveyed in several reviews [3][4][5][6][7][8][9][10]. Catalysis by solid bases and the mechanism of base-catalyzed reactions such as isomerization of alkenes and alkynes, aldol addition and aldol condensation, Henry reaction (nitro-aldol reaction), Knoevenagel condensation, Michael addition, the Tishchenko reaction, alkylation reactions, and addition reactions such as addition of amines to epoxides, transfer hydrogenation (Meerwein-Ponndorf-Verley (MPV) reaction), esterification and transesterification, and liquid-phase oxidations including Baeyer-Villiger oxidation and alkene epoxidation have been recently emphasized by Ono and Hattori [11], encompassing many splendid reviews and papers [12][13][14][15][16][17][18][19][20].The first part of this chapter is intended to survey recent literature on new catalytic materials because the development of new types of metal oxides and layered-and carbon-based materials with different morphologies opens up novel acid-base catalysis that enables new type of clean reaction technologies. Mechanistic considerations of acid-and base-catalyzed reactions should result in new clean catalytic processes for Green and Sustainable Chemistry, for example, transformations of biorenewable feedstock into value-added chemicals and fuels [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. The latter part of this chapter, therefore, focuses on biomass conversion using solid acid and base catalysts, which covers recent developments on acid-base, one-pot reaction systems for carbon-carbon bond formations, and biomass conversion including synthesis of furfurals from sugars, biodiesel production, and glycerol utilization.

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Brønsted Acid Property of Alumina-Supported Niobium Oxide Calcined at High Temperatures: Characterization by Acid-Catalyzed Reactions and Spectroscopic Methods

Cited by 42 publications

References 82 publications

Steam Reforming of Dimethyl Ether over Composite Catalysts of Supported Transition Metal Oxides and Cu/ZnO/Al<sub>2</sub>O<sub>3</sub>

Steam Reforming of Dimethyl Ether over Composite Catalysts of Supported Transition Metal Oxides and Cu/ZnO/Al<sub>2</sub>O<sub>3</sub>

Characterization of Thermally Stable Brønsted Acid Sites on Alumina‐Supported Niobium Oxide after Calcination at High Temperatures

Mechanistic Studies of Solid Acids and Base‐Catalyzed Clean Technologies

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