Highly Active Mesoporous Nb–W Oxide Solid‐Acid Catalyst

Tagusagawa, Caio; Takagaki, Atsushi; Iguchi, Akihiro; Takanabe, Kazuhiro; Kondo, Junko N.; Ebitani, Kohki; Hayashi, Shigenobu; Tatsumi, Takashi; Domen, Kazunari

doi:10.1002/anie.200904791

Cited by 125 publications

(72 citation statements)

References 77 publications

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“…Nevertheless, the sol-gel strategy, directly incorporating tungsten species into metal oxide composites, is supposed to afford a homogenous distribution of tungsten oxide, as well as a high stability for anti-aggregation. [18][19][20][21][22] Mesoporous TiO 2 is widely studied due to the variety of its potential applications. 23 It was reported that the crystallization temperature of TiO 2 was much lower than that of tungsten oxide, 24 and the solid solution of TiO 2 and WO 3 was formed over 700 C.…”

Section: Introductionmentioning

confidence: 99%

Mesoporous Ti–W oxide: synthesis, characterization, and performance in selective hydrogenolysis of glycerol

et al. 2013

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Mesoporous Ti-W oxides, bearing high surface area, large pore volume, uniform pore size and tunable W/Ti ratios in a wide range (10-40 mol%), were successfully fabricated via an evaporation-induced selfassembly (EISA) strategy. In this approach, the incorporation of W species not only effectively resulted in well-ordered mesoporous structures when calcined below 400 C but also modified the acidic properties of the obtained oxide composites. The optimal acid amounts (0.47-0.67 mmol g À1 for 400 C calcinations, 0.25-0.27 mmol g À1 for 500 C calcinations) were obtained when the W concentration was between 10 and 20 mol%. When calcined at 500 C, Brønsted acids were generated in Ti 90 W 10 -500 and Ti 80 W 20 -500. The catalytic performance of these mesoporous solid acids in glycerol hydrogenolysis was studied with a loading of 2 wt% Pt. Pt/Ti 100Àn W n -500s exhibited high selectivity to 1,3-propanediol (33.5% and 40.3%) and promising catalytic activities (18.4% and 24.2% glycerol conversion) when n is 10 and 20, respectively. This work presents a step forward in the development of highly efficient glycerol hydrogenolysis catalysts and a new understanding of the reaction mechanism of glycerol hydrogenolysis to 1,3-propanediol.

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Section: Introductionmentioning

confidence: 99%

Mesoporous Ti–W oxide: synthesis, characterization, and performance in selective hydrogenolysis of glycerol

et al. 2013

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“…These materials have been used in the isomerization of alkanes and other petrochemical processes such as alkylation of aromatics and hydrocarbon cracking [105]. Monometallic oxides such as MgO [106], SnO2 [107], WO3 [108], ZrO2 [109], TiO2 [110], Al2O3 [111], Nb2O5 [112], Ta2O5 [113], and bimetallic oxides such as Nb-Ta oxides [114,115], Mg-Ta oxides [116], Nb-W oxides [117], Sn-W oxides [118], Zr-W oxides [119], and WO3-TiO2 [120,121] have been extensively explored. The transition-metal centers in the inorganic frameworks of porous structures also possess variable oxidation states and empty d-orbitals, which allow electron transfer to occur between the reactants and active sites during the catalytic process [122].…”

Section: Mo-sno2 Metal Oxide Nanocomposite Catalystsmentioning

confidence: 99%

Sn-based catalysts for Baeyer-Villiger oxidations by using hydrogen peroxide as oxidant

Cui

Shi

2016

Sci. China Mater.

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Baeyer-Villiger (BV) oxidation is one of the most important transformation reactions in synthetic organic chemistry. Catalytic versions of the BV oxidation are particularly attractive in practical applications, because the catalytic transformation substantially simplifies reaction process while minimizing reactant consumption as well as waste production. Further benefits are expected from replacing peracids, the traditionally used oxidant, by low cost and environmentally friendly hydrogen peroxide (H2O2). This review will first introduce very briefly the features of BV oxidation reactions, and the corresponding oxidants traditionally used. Afterwards, the emphasis will be placed on the specific Sn-based catalysts, their performance comparison for the BV oxidation reaction by using H2O2 as oxidant, and the catalytic mechanisms of most Sn-based catalysts reported so far, including homogeneous Sn-based catalysts (such as Sn-based fluorous biphase system catalysts), heterogeneous Sn-based catalysts (such as Sn-based zeolite catalysts, Sn-based mesoporous composites, Sn-incorporated clay catalysts, Sn-based metal oxide composites and polymer supported Sn catalysts). Finally, the Sn-based catalysts for BV oxidation are outlooked for their potentials and perspectives in enhancing the performance and then accelerating the practical applications of BV oxidations by using H2O2. The developing direction of the Sn-based catalytic BV reaction is also illustrated.

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“…Mesoporous Nb-W and Ta-W mixed oxides were found to exhibit remarkable acid catalytic activity for Friedel-Crafts alkylation and the hydrolysis of sugars and esterification, surpassing conventional solid acids owing to their high surface area, mesoporous structure, and strong Brønsted acid sites (−12 ≤ H 0 < −6.6) [61,62]. In addition, mesoporous Nb-W and Ta-W oxides have the significant advantages of recyclability and thermal stability.…”

Section: New Catalytic Systemsmentioning

confidence: 99%

“…Water-tolerant solid acids, such as layered HNbMoO 6 [55,151], HTaMoO 6 [54], mesoporous Nb-W oxides [61], and Ta-W oxides [62], showed high activity for cellobiose hydrolysis, a unit of cellulose. The high performance of layered oxides is attributed to facile intercalation of cellobiose into the interlayer gallery containing strong Brønsted acid sites.…”

Section: Hydrolysis Of Cellulosementioning

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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Highly Active Mesoporous Nb–W Oxide Solid‐Acid Catalyst

Cited by 125 publications

References 77 publications

Mesoporous Ti–W oxide: synthesis, characterization, and performance in selective hydrogenolysis of glycerol

Mesoporous Ti–W oxide: synthesis, characterization, and performance in selective hydrogenolysis of glycerol

Sn-based catalysts for Baeyer-Villiger oxidations by using hydrogen peroxide as oxidant

Mechanistic Studies of Solid Acids and Base‐Catalyzed Clean Technologies

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