Use of Polyoxometalate Catalysts in Ionic Liquids to Enhance the Dissolution and Delignification of Woody Biomass

Sun, Ning; Jiang, Xinyu; Maxim, Mirela L.; Metlen, Andreas; Rogers, Robin D.

doi:10.1002/cssc.201000272

Cited by 73 publications

(60 citation statements)

References 24 publications

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“…As observed in Table 1 and Figure 2, the addition of POM to [C 2 mim][OAc] leads to a lower residue yield (63.0 wt % for Trial 1 vs 44.5 wt % for Trial 2) and a higher yield of CRM (16.8 wt % for Trial 1 vs 36.1 wt % for Trial 2) with lower lignin content (13.6 wt % for Trial 1 vs 10.5 wt % for Trial 2), in accordance with our previous results; 6 nonetheless, the bulk of the pine sample remains undissolved under these conditions. It is apparent, however, that complete dissolution of the pine can be easily achieved when bubbling O 2 into the IL solution under the same cooking conditions (110°C, 6 h) even when using only a small amount of POM (0.01 g [C 2 mim]POM, Trial 5).…”

Section: ■ Characterizationsupporting

confidence: 92%

“…11 −15 In addition, Ru, Rh, or Pt nanoparticles, combined with a series of Brønsted acidic imidazolium ILs, can hydrogenate and deoxygenate phenolic lignin model compounds to nonaromatic hexane species. 16 According to the reported mechanism of POM action (eqs 1 and 2), 9,17−19 6 All other solvents were obtained from Sigma-Aldrich(St. Louis, MO) and used as received.…”

Section: ■ Introductionmentioning

confidence: 99%

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Oxygen Enhances Polyoxometalate-based Catalytic Dissolution and Delignification of Woody Biomass in Ionic Liquids

Cheng

Wang

Rogers

2014

ACS Sustainable Chem. Eng.

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Complete dissolution and over 90% delignification of Southern yellow pine (<0.125 mm) can be achieved in the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C 2 mim][OAc]) at 110°C for 6 h by the catalytic action of polyoxometalate in the presence of an appropriate O 2 feed. Cellulose-rich materials (CRMs), or pulps, and hemicellulose with a limited lignin content and free lignin were subsequently recovered by adding antisolvents to the IL solution, followed by filtration. Comparison of wood processing in [C 2 mim][OAc]/POM with or without O 2 revealed that the presence of oxygen can greatly facilitate the dissolution, delignification, separation of hemicellulose, and oxidation of lignin. The main products from lignin oxidation were extracted from the IL using benzene and then tetrahydrofuran, and were shown by gas chromatography−mass spectrometry (GC−MS) to be methyl vanillate, acetovanillone, vanillic acid, methyl 3-(3-methoxy-4-hydroxyphenyl) propionate, and methyl 4-hydroxybenzoate. This study suggests that treating wood with a [C 2 mim][OAc]/POM/O 2 system could be a viable strategy to separate wood components with high efficiency and obtain cellulose with high purity for materials or biorefinery applications, particularly those that desire smaller lignin oxidation fragments for further processing. ■ INTRODUCTIONIonic liquids (ILs), generally defined as salts that are liquid below 100°C, 1 have been recognized as promising solvents for the processing of lignocellulosic biomass, one of the potentially sustainable energy sources. 2,3 However, the complex recalcitrant structure and the entangled and covalently cross-linked polymeric matrix of wood, greatly hinder its rapid dissolution and efficient fractionation in ILs. 3,4 In 2011, we showed that the polyoxometalate (POM, a transition metal oxide anionic cluster 5 ) [PV 2 Mo 10 O 40 ] 5− could efficiently catalyze the dissolution and delignification of Southern yellow pine in 1-ethyl-3-methylimidazolium acetate ([C 2 mim][OAc]). 6 The time for complete dissolution of 0.5 g of pine in 10 g of [C 2 mim][OAc] was reduced from 46 to 16 h in the presence of POM, and the recovered cellulose-rich materials (CRMs) had a lower lignin content (5.4−18.3 wt % vs 23.5 wt %), although the yield of isolated lignin decreased (8.0−27.0 wt % vs 31.4 wt %) due to degradation of lignin. Although the addition of POM greatly enhanced the dissolution of wood in the IL, it still required a relatively long time to completely dissolve the wood (e.g., 16 h at 110°C for pine) and the lignin content of the recovered CRM was high, ranging from 5.4 to 18.3 wt %.POMs have previously been explored in the delignification and bleaching of lignocellulosic pulp in aqueous solution, 7,8 and the oxidation of starch in ILs. 9 Recently, Albert et al. reported the oxidation of woody biomass to formic acid at 90°C under 30 bar O 2 in aqueous solution using POM (H 5 PV 2 Mo 10 O 40 ) as the catalyst, and formic acid yields reached 15.8 wt % in the processing of pine. 10 Besides POMs, metal chlor...

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Section: ■ Characterizationsupporting

confidence: 92%

Section: ■ Introductionmentioning

confidence: 99%

Oxygen Enhances Polyoxometalate-based Catalytic Dissolution and Delignification of Woody Biomass in Ionic Liquids

Cheng

Wang

Rogers

2014

ACS Sustainable Chem. Eng.

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“…Fine-tuning of these properties is further possible by structural modification, and given the generally high molecular weight of the ions, the use of functional ions to make ILs or the addition of functional groups for specific tasks is moderately trivial and widely employed. [25,26] Major interest in IL for biomass dissolution and processing was triggered by the seminal paper of Rogers et al in 2002, [27] which 'rediscovered' and significantly advanced Graenacher's observation that the organic salt N-ethylpyridinium chloride mixed with pyridine could dissolve cellulose. [28] They found [Bmim]Cl to be the most effective solvent for cellulose, dissolving up to 25 wt-%.…”

Section: Dissolution Of Lignocellulosic Biomass With Ionic Liquidsmentioning

confidence: 98%

“…Li [26] or loss of polyoxometallates when employed in ILs as pulping agents. [25] Reported mass loss of IL is not necessarily a concern given the small scale most experiments are operated on, although contamination of the downstream products with IL is of more significant concern; [72] both can potentially be minimized on an industrial scale. One concern is the vast quantity of energy required for the distillation steps in the use of antisolvents, [29,30] which is where the selective removal of just one component followed by processing of that component in the IL is noted as a promising alternative.…”

Section: Utilizing [Emim][abs] [Emim] [Oac] and [Ch]mentioning

confidence: 99%

Ionic Liquids for Lignin Processing: Dissolution, Isolation, and Conversion

Hossain¹,

Aldous²

2012

Aust. J. Chem.

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We present a review on the multifunctional use of ionic liquids with respect to lignin processing. In a biorefinery context, lignocellulosics could be used to provide sustainable sources of fuels such as bioethanol, and feedstock molecules for the chemical industry such as phenols and other aromatics. However, separation of lignin from cellulose and hemicellulose is a vital step. Ionic liquids can dissolve extensive quantities of biomass, and even be designed to be multifunctional solvents. We highlight the use of ionic liquids in selectively or non-selectively dissolving lignin, the depolymerization reactions that have been attempted on lignin in ionic liquids, and the effect ionic liquids have been observed to have on such processes. Finally, we present some of the challenges and issues that must be addressed before the informed and large-scale application of ionic liquids can be realized for lignin processing.

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“…In addition, this is done from an agricultural residue with negligible cost. Although a number of ILs have been shown to directly dissolve lignocellulosic material, with partial separation of the constitutive major biopolymers, still a clean separation of cellulose cannot be attained (Sun et al 2009(Sun et al , 2010. Thus, a more conventional strategy has been followed for the pulping stage of production of cellulose from the agricultural waste, using an inorganic method based on sodium hydroxide.…”

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Physicochemical properties of maize cob cellulose powders reconstituted from ionic liquid solution

et al. 2011

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Suitable a-cellulose and cellulose II powders for use in the pharmaceutical industry can be derived from maize cob. a-Cellulose was extracted from an agricultural residue (maize cobs) using a nondissolving method based on inorganic substances. Modification of this a-cellulose was carried out by its dissolution in the ionic liquid 1-butyl-3-methylimidazolium chloride ([C 4 mim]Cl), and subsequent regeneration by addition of either water or acetone at room temperature, or of boiling water. X-ray diffraction and infrared spectroscopy results showed that the regenerated celluloses had lower crystallinity, and proved that the treatment with [C 4 mim]Cl led to the conversion of the crystalline structure of a-cellulose from cellulose I to cellulose II. Thermogravimetric analysis and differential scanning calorimetry data showed quite similar thermal behavior for all cellulose samples, although with somewhat lower stability for the regenerated celluloses, as expected. The comparison of physicochemical properties of the regenerated celluloses and the native cellulose mainly suggests that the regenerated ones might have better flow properties. For some of the characterizations carried out, it was generally observed that the sample regenerated with boiling water had more similar characteristics to the a-cellulose sample, evidencing an influence of the regeneration strategy on the resulting powder after the ionic liquid treatment.

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Use of Polyoxometalate Catalysts in Ionic Liquids to Enhance the Dissolution and Delignification of Woody Biomass

Cited by 73 publications

References 24 publications

Oxygen Enhances Polyoxometalate-based Catalytic Dissolution and Delignification of Woody Biomass in Ionic Liquids

Oxygen Enhances Polyoxometalate-based Catalytic Dissolution and Delignification of Woody Biomass in Ionic Liquids

Ionic Liquids for Lignin Processing: Dissolution, Isolation, and Conversion

Physicochemical properties of maize cob cellulose powders reconstituted from ionic liquid solution

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