Hydrothermal degradation of alkali lignin to bio-phenolic compounds in sub/supercritical ethanol and water–ethanol co-solvent

Cheng, Shuna; Wilks, Carolynne; Yuan, Zhongshun; Leitch, Mathew; Xu, Chunbao

doi:10.1016/j.polymdegradstab.2012.03.044

Cited by 191 publications

(143 citation statements)

References 26 publications

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“…The AL sample had a smaller percentage of detectable phenolic compounds because it was composed of simpler structural units or smaller molecules due to the alkali hydrolysis in the cooking process (Table 2). GPC results from past studies (Cheng et al 2012) also supported this observation. Additionally, the following trends were observed: The guaiacol and 2,6-dimethoxyphenol from AL sample accounted for 16.52% and 18.01% of the total peak area over 10 min, respectively.…”

Section: Liquid Product Analysis Qualitative Analyses Of Phenolic Comsupporting

confidence: 75%

“…The aliphatic side-chain containing phenylproane units in lignin was relatively plasma insensitive, but easily cleaved when treated under supercritical water conditions as observed by Tang et al (2010). Thus, alcohols could be generated by the cleavage of both ether linkages and lignin side chains (Cheng et al 2012). The AL sample had a smaller percentage of detectable phenolic compounds because it was composed of simpler structural units or smaller molecules due to the alkali hydrolysis in the cooking process (Table 2).…”

Section: Liquid Product Analysis Qualitative Analyses Of Phenolic Commentioning

confidence: 97%

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Supercritical Water-induced Lignin Decomposition Reactions: A Structural and Quantitative Study

Jiang¹,

Lyu²,

Wu³

et al. 2016

BioResources

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The use of supercritical water for the decomposition of lignin and evaluation of its influence on lignin decomposition and conversion to various products was the thrust of the current study. Poplar alkali lignin (AL), corncob-to-xylitol residue lignin (XRL), and cornstalk-to-ethanol residue lignin (ERL) were the lignin species studied because they constitute the main residual lignins available in the biomass refinery industry. The lignins were characterized by elementary analysis, Fourier transform infrared spectrometry (FT-IR), phosphorus nuclear magnetic resonance ( 31 P-NMR), and X-ray diffraction (XRD), and their hydrothermal depolymerization products were analyzed by gas chromatography-mass spectrometer (GC-MS). The results showed that the residual lignin is a potential source for valuable aromatics. The XRL had the best total phenolics yield, 140 mg/g, while AL had the lowest, 90 mg/g. The maximum yields of phenol (28.94 mg/g) and 4-ethylphenol (36.21 mg/g) were obtained from XRL depolymerization at 375 °C for 30 min, and the optimal yields of guaiacol (14.34 mg/g) and 2,6-dimethoxyphenol (15.67 mg/g) were achieved by AL at 375 °C for 30 min. The information here provides some insights toward developing selective biorefinery methods for lignin-to-organic products conversion processes.

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Section: Liquid Product Analysis Qualitative Analyses Of Phenolic Comsupporting

confidence: 75%

Section: Liquid Product Analysis Qualitative Analyses Of Phenolic Commentioning

confidence: 97%

Supercritical Water-induced Lignin Decomposition Reactions: A Structural and Quantitative Study

Jiang¹,

Lyu²,

Wu³

et al. 2016

BioResources

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“…At the end of the reaction, aliphatic compounds in C 6 alcohols and C 8 -C 10 esters, as well as aromatic compounds in the form of C 8 -C 10 arenes, phenols and benzyl alcohols were produced. 25 products were identified and quantified and their overall total yield was 1.64 g per gram of lignin; almost 15 times more than the yield obtained with noble metal-based catalysts [70]. Due to the fact that the obtained yield is over 100%, it can be assumed that ethanol participates in the reaction.…”

Section: Ligninmentioning

confidence: 99%

Metal Carbides for Biomass Valorization

Chan‐Thaw

Villa

2018

Applied Sciences

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Transition metal carbides have been utilized as an alternative catalyst to expensive noble metals for the conversion of biomass. Tungsten and molybdenum carbides have been shown to be effective catalysts for hydrogenation, hydrodeoxygenation and isomerization reactions. The satisfactory activities of these metal carbides and their low costs, compared with noble metals, make them appealing alternatives and worthy of further investigation. In this review, we succinctly describe common synthesis techniques, including temperature-programmed reaction and carbothermal hydrogen reduction, utilized to prepare metal carbides used for biomass transformation. Attention will be focused, successively, on the application of transition metal carbide catalysts in the transformation of first-generation (oils) and second-generation (lignocellulose) biomass to biofuels and fine chemicals.

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“…The yield rates of DEL increased with temperature until reaching a maximum at 250 °C. Various studies (Yuan et al 2010;Cheng et al 2012) of lignin have shown that the β-O-4 bond is readily ruptured at temperatures ranging from 200 to 300 °C (degradative reaction of lignin in various solvents). However, when the temperature was increased from 250 to 300 °C, the yield rate and reactivity toward formaldehyde of DEL considerably reduced, and residue rate largely increased.…”

Section: Effect Of Degradation Temperaturementioning

confidence: 99%

Hydrothermal Degradation of Enzymatic Hydrolysis Lignin in Water-Isopropyl Alcohol Co-Solvent

Qiao

et al. 2016

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The effect of hydrothermal conditions on enzymatic hydrolysis lignin (EHL) degradation in water-isopropyl alcohol co-solvent and optimal conditions were investigated. The yields and reactivity toward formaldehyde of degraded enzymatic hydrolysis lignin (DEL) were determined. The optimal conditions of temperature, time, and ratio of solids to liquids were 250 °C, 60 min, and 1:10 (w/v), respectively. The EHL and DEL were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), 1 H nuclear magnetic resonance ( 1 H NMR), thermal gravity (TG), and differential scanning calorimetry (DSC) analyses. The results revealed that the molecular weight and polydispersity of DEL were lower than that of EHL. Although the fundamental structure of lignin before and after hydrothermal degradation was retained, the ether (β-O-4, α-O-4, etc.) content decreased, while that of hydroxyl (phenolic and aliphatic) increased. The DTGmax and Tg values shifted from 334 and 117 °C to 304 and 105 °C, respectively.

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Hydrothermal degradation of alkali lignin to bio-phenolic compounds in sub/supercritical ethanol and water–ethanol co-solvent

Cited by 191 publications

References 26 publications

Supercritical Water-induced Lignin Decomposition Reactions: A Structural and Quantitative Study

Supercritical Water-induced Lignin Decomposition Reactions: A Structural and Quantitative Study

Metal Carbides for Biomass Valorization

Hydrothermal Degradation of Enzymatic Hydrolysis Lignin in Water-Isopropyl Alcohol Co-Solvent

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