ChemSusChem
·
2016
·Vol. 10
·期 3
·523-532
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IF 7.116
Haiwei Guo,Bo Zhang,Zaojuan Qi,Changzhi Li,Jianwei Ji,Tao Dai,Aiqin Wang,Tao Zhang
Graphical W 2 C activity : Non-noble metal catalyst tungsten carbide shows high activity in the selective deconstruction of various lignin feedstocks to phenolic oils, and the impact of the structure differences on the activity of tungsten carbide is well studied. Softwood lignin shows lower hydrocracking efficiency than hardwood lignin, mainly owing to the higher molecular weights and the existence of more resistant linkages. Lignins isolated from representative hardwood, softwood, and grass materials were effectively hydrocracked to aromatics catalyzed by tungsten carbide over activated carbon (W 2 C/AC). The effects of botanical species and fractionation methods on lignin structure and the activity of W 2 C/AC were studied in detail. Gas permeation chromatography (GPC), FTIR, elemental analysis, and 2 D HSQC NMR showed that all the extracted samples shared the basic skeleton of lignin, whereas the fractionation method significantly affected the structure. The organosolv process provided lignin with a structure more similar to the native lignin, which was labile to be depolymerized by W 2 C/AC. Softwood lignins (i.e., spruce and pine) possessed higher molecular weights than hardwood lignins (i.e., poplar and basswood); whereas corn stalk lignin that has noncanonical subunits and exhibited the lowest molecular weight owing to its shorter growth period. β-O-4 bonds were the major linkages in all lignin samples, whereas softwood lignins contained more resistant linkages of β-5 and less β-β than corn stalk and hardwood lignins; as a result, lowest hydrocracking efficiency was obtained in softwood lignins, followed by corn stalk and hardwood lignins. 2 D HSQC NMR spectra of lignin and the liquid oil as well as the solid residue showed that W 2 C/AC exhibited high activity not only in β-O-4 cleavage, but also in deconstruction of other ether linkages between aromatic units, so that high yield of liquid oil was obtained from lignin.
研究领域:
化学工程
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生物质能
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DOI
PubMed
高影响因子
Polymers
·
2024
·Vol. 16
·期 10
·1403
·
IF 4.7
Shuyu Pang,Xin Wang,Jiali Pu,Chen Liang,Shuangquan Yao,Chengrong Qin
Hemicellulose extracted by alkali treatment is of interest because of the advantages of its intact sugar structure and high degree of polymerization. However, the hemicellulose extracted by alkali treatment contained more lignin fragments and the presence of a lignin–carbohydrate complex (LCC), which affected the isolation and purification of hemicellulose and its comprehensive utilization. Therefore, the evaluation of the LCC structure of different types of lignocellulosic resources is of great significance. In this study, the LCC structures of hardwoods and Gramineae were enriched in alkaline systems. Information on the composition, structural proportions, and connection patterns of LCC samples was discussed. The similarities and differences between the LCC structures of different units of raw materials were comparatively studied. The results indicated that the monosaccharide fractions were higher in the LCC of Gramineae compared to hardwoods. The composition of the lignin fraction was dominated by G and S units. The phenyl glycosidic (PhGlc) bond is the predominant LCC linkage under alkali-stabilized conditions. In addition, Gramineae PhGlc types are more numerous compared to hardwoods. The results of the study provide insights into the differences in the chemical composition and structural features of LCC in different plants and provide important guidance for the optimization of the process of purifying hemicellulose.
研究领域:
植物学
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生物化学
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DOI
PubMed
高影响因子
ChemSusChem
·
2023
·
IF 8.4
Jing Bai,Hao Li,Yuting Zhu,Yiping Zhu,Chenguang Wang,Haiyong Wang,Yuhe Liao
Graphical From the hardwood : A route was developed to transform hardwood lignin toward 2,6-dimethoxy- p -aminophenol with high yield and keeping the inherent functional groups. Lignin was first oxidized to syringaldehyde, which was converted toward 2,6-dimethoxy- p -aminophenol via oxidation, oximation, and hydrogenation. The presence of the methoxy group guaranteed the high selectivity. Although the multiple functional groups in biomass offer notable chances for producing high-value chemicals, most of the current studies focused on the (deep) defunctionalization of biomass and its derivates. Herein, we present a catalytic approach to valorize birch wood lignin with maintaining the methoxy and hydroxy groups in the final product (i. e., 2,6-dimethoxy- p -aminophenol), which has applications in different sectors such as pharmaceuticals. The proved approach involves four steps with a high yield (19.8 wt % on the basis of used lignin) to 2,6-dimethoxy- p -aminophenol. The native lignin in birch wood was first converted using alkaline aerobic oxidation in the presence of copper ions toward high-yield syringaldehyde, which was then selectively oxidized toward 2,6-dimethoxy-1,4-benzoquinone using H 2 O 2 and V 2 O 5 . Oximation of 2,6-dimethoxy-1,4-benzoquinone can selectively form 2,6-dimethoxy-1,4-benzoquinone-4-oxime, which can be quantitatively hydrogenated toward 2,6-dimethoxy- p -aminophenol. This work highlights the unique potential of biomass and its derivates for the sustainable production of high-value products with exploring the value of inherent functional groups.
研究领域:
化学工程
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生物质利用
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制药科学
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DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Xiaoning Tang,Gaozhe Liu,Heng Zhang,Xin Gao,Meng Li,Shumei Zhang
In this study, we report a novel, facile, and green method that was used for creating a new all-cellulose composite (ACC) based on inorganic molten salt solvent. Three representatively native fibers from softwood ( Pinus kesiya ), hardwood ( Eucalyptus globulus ), and agricultural straw ( Zea mays ) were selected to verify the effect of the method. The welded sheets were thoroughly characterized and compared. Cellulose sheets from the pine exhibited excellent mechanical properties (σb 16.94 MPa) and thermal stability (T max 265 °C) after the welding process, while the corn stalk sheets displayed more robust and thermostable features than the eucalyptus. The welding technique using inorganic metal salt hydrate provides a promising and convenient route to obtain firm sheet-materials with micro- or nano-structures from nature fibers.
研究领域:
材料科学
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林业工程
·
绿色化学
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DOI
PubMed
高影响因子
CELLULOSE
·
2017
·Vol. 24
·期 11
·4831-4844
·
IF 3.417
Chen Yufei,Geng Biyao,Ru Jing,Tong Congcong,Liu Hongzhi,Chen Jinzhou
Bamboo, softwood, and hardwood pulp fibers were used as starting materials to prepare TEMPO-oxidized nanofibrillated cellulose (TO-NFC) dispersions. The resulting TO-NFC dispersions were then used to fabricate cellulose nanopapers and to coat poly(lactic acid) (PLA) films. The chemical and morphological characteristics of the dispersions together with the physical properties of the resultant nanopaper and PLA films were systematically compared. The maximum degree of oxidation was achieved for the bamboo pulp fiber. Transmission electron microscopy micrographs revealed that the oxidized pulp fibers were successfully disintegrated into cellulose nanofibrils with an average width of 5–6 nm. However, bamboo-derived TO-NFC was more densely entangled and crimped, with a heterogeneous distribution in width. It was further revealed that morphologies of the obtained TO-NFC may arise from the organizational structure of microfibrils in the cellulose fibers rather than the presence of hemicelluloses or the pulping process. The PLA films coated with a thin layer of TO-NFC from the bamboo pulp exhibited the highest oxygen-barrier property, which was even slightly higher than commercial ethylene–vinyl alcohol copolymer film, known for its high oxygen-barrier functionality.
研究领域:
材料科学
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林业工程
·
高分子化学
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Yidong Zhang,Wangfang Deng,Chao Liu,Fei Yan,Meiyan Wu,Qiu Cui,Stefan Willför,Chunlin Xu,Bin Li
Dialdehyde nanocellulose (DANC), obtained via periodate oxidation, has been widely used in foods, cosmetics, and biomedical fields due to its unique characteristics. However, the high-crystallinity and tight structure of cellulose retards the efficiency of periodate oxidation for producing DANC. Herein, a novel sustainable and clean approach with less energy consumption and low cost was developed through LiBr·3H2O (LBTH) non-dissolving pretreatment, which can shorten the oxidation time of the followed periodate oxidation and reduce the oxidant consumption. It was shown that the cellulose Iβ structure of hardwood dissolving pulp (HDP) was largely transformed into an amorphous structure after LBTH non-dissolving pretreatment for 30 min, and the corresponding crystallinity of HDP was reduced from 83.2 to 48.7%. After pretreatment for 60 min, the aldehyde group content of the obtained DANC increased by around 30% compared to the control without pretreatment while the operational cost was reduced by 45%. Moreover, the fabricated DANC showed strong antibacterial activity against both Escherichia coli and Bacillus subtilis. LBTH was recovered and reused, and the pretreatment effectiveness was also maintained. This study provides a sustainable, cost-effective, and clean approach for the preparation of DANC and will promote the application of cellulose nanomaterials.
研究领域:
材料科学
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化学工程
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生物医学工程
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纳米技术
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DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2016
·
IF 4.917
Cheng Cai,Xueqing Qiu,Xuliang Lin,Hongming Lou,Yuxia Pang,Dongjie Yang,Siwei Chen,Kaifan Cai
Two pretreatment methods to overcome recalcitrance of lignocelluloses, sulfite pretreatment (SPORL) and dilute acid (DA), were conducted to pretreat softwood masson pine and hardwood eucalyptus for enzymatic hydrolysis. In the presence of corresponding pre-hydrolysates, adding moderate cetyltrimethylammonium bromide (CTAB) could enhance the enzymatic hydrolysis of the SPORL-pretreated substrates, but had no enhancement for the DA-pretreated substrates. The results showed that sodium lignosulfonate (SL) in pre-hydrolysates and CTAB together had a strong enhancement on the enzymatic hydrolysis of lignocelluloses. The compound of commercial lignosulfonate SXSL and CTAB (SXSL-CTAB) could enhance the substrate enzymatic digestibility (SED) of SPORL-pretreated masson pine from 27.1% to 71.0%, and that of DA-pretreated eucalyptus from 37.6% to 67.9%. The mechanism that CTAB increased the adsorption of SL on lignin to form more effective steric hindrance and reduced the non-productive adsorption of cellulase on lignin by neutralizing the negative charge of SL was proposed.
研究领域:
生物化学
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生物技术
·
化学工程
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DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）