Catalytic conversion of cellulose into ethylene glycol over supported carbide catalysts

Ji, Na; Zhang, Tao; Zheng, Mingyuan; Wang, Aiqin; Wang, Hui; Wang, Xiaodong; Shu, Yeqiang; Stottlemyer, Alan L.; Chen, Jingguang G.

doi:10.1016/j.cattod.2009.03.012

Cited by 157 publications

(105 citation statements)

References 27 publications

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“…16 Consistent with the breakthrough in the properties of water at or above 513 K, elevating the reaction temperature from 503 to 513 K led to an increase of cellulose conversion by ∼30% over W 2 C/AC catalyst. 7,21 Evidently, hot water plays a key role in promoting the dissolution and hydrolysis of cellulose, which in turn accelerates the subsequent hydrogenolysis reaction for production of EG. Actually, in other solvents such as ethanol or supercritical CO 2 , the conversion of cellulose was negligible.…”

Section: Reaction Mechanismmentioning

confidence: 99%

One-Pot Conversion of Cellulose to Ethylene Glycol with Multifunctional Tungsten-Based Catalysts

2013

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W ith diminishing fossil resources and increasing concerns about environmental issues, searching for alternative fuels has gained interest in recent years. Cellulose, as the most abundant nonfood biomass on earth, is a promising renewable feedstock for production of fuels and chemicals. In principle, the ample hydroxyl groups in the structure of cellulose make it an ideal feedstock for the production of industrially important polyols such as ethylene glycol (EG), according to the atom economy rule. However, effectively depolymerizing cellulose under mild conditions presents a challenge, due to the intra-and intermolecular hydrogen bonding network. In addition, control of product selectivity is complicated by the thermal instabilities of cellulosederived sugars. A one-pot catalytic process that combines hydrolysis of cellulose and hydrogenation/hydrogenolysis of cellulose-derived sugars proves to be an efficient way toward the selective production of polyols from cellulose.In this Account, we describe our efforts toward the one-pot catalytic conversion of cellulose to EG, a typical petroleumdependent bulk chemical widely applied in the polyester industry whose annual consumption reaches about 20 million metric tons. This reaction opens a novel route for the sustainable production of bulk chemicals from biomass and will greatly decrease the dependence on petroleum resources and the associated CO 2 emission. It has attracted much attention from both industrial and academic societies since we first described the reaction in 2008. The mechanism involves a cascade reaction. First, acid catalyzes the hydrolysis of cellulose to water-soluble oligosaccharides and glucose (R1). Then, oligosaccharides and glucose undergo CÀC bond cleavage to form glycolaldehyde with catalysis of tungsten species (R2). Finally, hydrogenation of glycolaldehyde by a transition metal catalyst produces the end product EG (R3). Due to the instabilities of glycolaldehyde and cellulose-derived sugars, the reaction rates should be r 1 , r 2 , r 3 in order to achieve a high yield of EG. Tuning the molar ratio of tungsten to transition metal and changing the reaction temperature successfully optimizes this reaction. No matter what tungsten compounds are used in the beginning reaction, tungsten bronze (H x WO 3 ) is always formed. It is then partially dissolved in hot water and acts as the active species to homogeneously catalyze CÀC bond cleavage of cellulose-derived sugars. Upon cooling and exposure to air, the dissolved H x WO 3 is transformed to insoluble tungsten acid and precipitated from the solution to facilitate the separation and recovery of the catalyst. On the basis of this temperature-dependent phase-transfer behavior, we have developed a highly active, selective, and reusable catalyst composed of tungsten acid and Ru/C. Our work has unearthed new understanding of this reaction, including how different catalysts perform and the underlying mechanism. It has also guided researchers to the rational design of catalysts for other reactions inv...

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Section: Reaction Mechanismmentioning

confidence: 99%

One-Pot Conversion of Cellulose to Ethylene Glycol with Multifunctional Tungsten-Based Catalysts

2013

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“…Carbide catalysts have been the subject of numerous theoretical and experimental investigations since their activity was compared to platinum by Levy and Boudart [12], and have proven to be active for many different reactions [8,3,13]. Molybdenum carbide in particular has shown catalytic activity for conversion of syngas to hydrocarbons and alcohols [14,15,16,17,18,19,20,8,21,22], steam/dry reforming [6,18,3,10,23,24,25], water-gas shift [26,27,28], methane aromatization [7,29,30], hydrocarbon hydrogenolysis [6,19,14,18], hydrocarbon hydrogenation [8,31,32] and various other reactions involving hydrocarbons and alcohols [8,33,30,34,35]. The activity and selectivity of molybdenum carbide differs depending on the synthesis procedure and reaction conditions [17], and can be tuned using alkali metal promoters such as potassium or rubidium [36,37].…”

Section: Introductionmentioning

confidence: 99%

Elementary steps of syngas reactions on Mo2C(001): Adsorption thermochemistry and bond dissociation

Medford

Vojvodić

Studt

et al. 2012

Journal of Catalysis

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Density functional theory (DFT) and ab initio thermodynamics are applied in order to investigate the most stable surface and subsurface terminations of Mo 2 C(001) as a function of chemical potential and in the presence of syngas. The Mo-terminated (001) surface is then used as a model surface to evaluate the thermochemistry and energetic barriers for key elementary steps in syngas reactions. Adsorbtion energy scaling relations and Brønsted-Evans-Polanyi relationships are established and used to place Mo 2 C into the context of transition metal surfaces. The results indicate that the surface termination is a complex function of reaction conditions and kinetics. It is predicted that the surface will be covered by either C 2 H 2 or O depending on conditions. Comparisons to transition metals indicate that the Mo-terminated Mo 2 C(001) surface exhibits carbon reactivity similar to transition metals such as Ru and Ir, but is significantly more reactive towards oxygen.

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“…The chemical transformation of cellulose into valuable chemicals, such as polyols, is currently regarded as an important way to produce chemicals from renewable resources and thus, reduce our dependence on fossil resources [1][2][3][4][5][6]. Fukuoka et al [1] have developed an environmentally friendly process for the direct conversion of cellulose into sugar alcohols by combining the hydrolysis of cellulose in hot water with the hydrogenation of glucose.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization, and catalytic application of highly ordered mesoporous alumina-carbon nanocomposites

Wang

et al. 2010

Nano Res.

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Highly ordered mesoporous carbon-alumina nanocomposites (OMCA) have been synthesized for the first time by a multi-component co-assembly method followed by pyrolysis at high temperatures. In this synthesis, resol phenol-formaldehyde resin (PF resin) and alumina sol were respectively used as the carbon and alumina precursors and triblock copolymer Pluronic F127 as the template. N 2 -adsorption measurements, X-ray diffraction, and transmission electron microscopy revealed that, with an increase of the alumina content in the nanocomposite from 11 to 48 wt.%, the pore size increased from 2.9 to 5.0 nm while the ordered mesoporous structure was retained. Further increasing the alumina content to 53 wt.% resulted in wormhole-like structures, although the pore size distribution was still narrow. The nanocomposite walls are composed of continuous carbon and amorphous alumina, which allows the ordered mesostructure to be well preserved even after the removal of alumina by HF etching or the removal of carbon by calcination in air. The OMCA nanocomposites exhibited good thermostability below 1000 °C ; at higher temperatures the ordered mesostructure partially collapsed, associated with a phase transformation from amorphous alumina into γ-Al 2 O 3 . OMCA-supported Pt catalysts exhibited excellent performance in the one-pot transformation of cellulose into hexitols thanks to the unique surface properties of the nanocomposite.

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Catalytic conversion of cellulose into ethylene glycol over supported carbide catalysts

Cited by 157 publications

References 27 publications

One-Pot Conversion of Cellulose to Ethylene Glycol with Multifunctional Tungsten-Based Catalysts

One-Pot Conversion of Cellulose to Ethylene Glycol with Multifunctional Tungsten-Based Catalysts

Elementary steps of syngas reactions on Mo2C(001): Adsorption thermochemistry and bond dissociation

Synthesis, characterization, and catalytic application of highly ordered mesoporous alumina-carbon nanocomposites

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