ACS Catalysis
·
2016
·
IF 9.307
Nengchao Luo,Min Wang,Hongji Li,Jian Zhang,Huifang Liu,Feng Wang
One of the challenges of depolymerizing lignin to valuable aromatics lies in the selective cleavage of the abundant C–O bonds of β-O-4 linkages. Herein we report a photocatalytic oxidation–hydrogenolysis tandem method for cleaving C–O bonds of β-O-4 alcohols. The Pd/ZnIn2S4 catalyst is used in the aerobic oxidation of α-C–OH of β-O-4 alcohols to α-C═O with 455 nm light, and then a TiO2–NaOAc system is employed for cleaving C–O bonds neighboring the α-C═O bonds through a hydrogenolysis reaction by switching to 365 nm light. Interestingly, the oxidation–hydrogenolysis tandem reaction can be conducted in one pot to offer ketones and phenols (up to 90% selectivity) via a dual light wavelength switching (DLWS) strategy. EPR and metal loading experiments elucidate that Ti3+ in TiO2 is formed in situ and is responsible for the photocatalytic hydrogenolysis through electron transfer from Ti3+ to the β-O-4 ketones.
研究领域:
化学工程
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2021
·
IF 3.605
Bin Hu,Wen-luan Xie,Yang Li,Zhen-xi Zhang,Ji Liu,Bing Zhang,Ti-peng Wang,Qiang Lu
The lignin pyrolysis process involves complex interaction reactions, where the bimolecular concerted interactions have been rarely studied. In the present work, an extended concerted interaction mechanism, hydroxyl-assisted hydrogen transfer (hydroxyl-AHT), was proposed based on the pyrolysis of the typical nonsubstituted and α-hydroxyl-substituted β-O-4 type lignin models (2-phenylethyl phenyl ether, PPE, and 2-phenoxy-1-phenylethanol, α-OH-PPE). This hydroxyl-AHT mechanism was investigated and confirmed with the combined fast pyrolysis experiments and quantum chemistry modeling. The results indicate that phenolic, watery, alcoholic, and enolic hydroxy compounds all can act as mediators for the concerted hydrogen transfer process in lignin pyrolysis and have similar assistant effects. Whereas, the hydroxyl-AHT has a great influence on the competitiveness of different concerted reactions to break the Cβ–O, Cα–Cβ, and Cα–OH bonds, respectively. To compare the pyrolysis of PPE and α-OH-PPE, the α-hydroxyl substituent leads to a significant promotion to the Cβ–O cleavage based on hydroxyl-AHT because there are more hydroxyl mediators and more concerted reaction types that can be involved in the bimolecular hydrogen transfer in α-OH-PPE pyrolysis. Hence, more phenol derived from the Cβ–O breakage was detected in the pyrolysis experiment of α-OH-PPE than that of PPE. In addition, this bimolecular hydroxyl-AHT interaction mechanism is universal in the concerted pyrolysis processes of lignin, also accelerating the cleavage of α-O-4 linkage, β-1 linkage, etc.
研究领域:
化学工程
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能源科学
✓ 已验证
DOI
高影响因子
iScience
·
2023
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IF 5.8
Luxian Guo,Yangming Ding,Hua Wang,Yuxuan Liu,Qian Qiang,Qi Luo,Fei Song,Changzhi Li
The catalytic conversion of lignin into N-containing chemicals is of great significance for the realization of value-added biorefinery concept. In this article, a one-pot strategy was designed for the transformation of lignin β-O-4 model compounds to imidazo[1,2-a]pyridines in yields up to 95% using 2-aminopyridine as a nitrogen source. This transformation involves highly coupled cleavage of C-O bonds, sp 3 C-H bond oxidative activation, and intramolecular dehydrative coupling reaction to construction of N-heterobicyclic ring. With this protocol, a wide range of functionalized imidazo[1,2-a]pyridines sharing the same structure skeleton as those commercial drug molecules, such as Zolimidine, Alpidem, Saripidem, etc., were synthesized from different lignin β-O-4 model compounds and one β-O-4 polymer, emphasizing the application feasibility of lignin derivatives in N-heterobicyclic pharmaceutical synthesis.
研究领域:
有机化学
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生物炼制
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药物化学
✓ 已验证
DOI
高影响因子
Sustainable Energy & Fuels
·
2022
·Vol. 6
·期 11
·2745-2754
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IF 6.813
Hua Tan,Xuecheng Li,Hao Ma,Xiaolin Yang,Tong Zhan,Wenyu Xie,Suhua Wang,Jiaping Zhu
Herein, N-doped carbon embedded Ni catalysts were prepared by a co-impregnation method followed by pyrolysis in a N2 atmosphere for transfer hydrogenolysis of lignin β-O-4 alcohol and ketone model compounds using isopropanol as the hydrogen source. It was found that pyrolysis at 800 °C resulted in the formation of graphitic N-doped carbon shell encapsulated Ni nanoparticles (Ni@NC-800). The obtained Ni@NC-800 exhibited higher activity and selectivity to aromatics in the conversion of 2-phenoxy-1-phenylthanol and 2-phenoxyacetophenone, compared with Ni@NC-600 and Ni/NC-800. Moreover, the selectivity to aromatics could be further improved over Ni@NC-800-H, which is Ni@NC-800 after strong acid leaching. However, the presence of Cα–OH in lignin β-O-4 model compounds was essential for their product distributions. The control and characterization experiments suggested that the catalytic reaction occurred on the surface of N-doped carbon shells, because the encapsulated Ni NPs could donate electrons to the outer shells, leading to surface electron enrichment, thus making inert shells the new active sites in Ni@NC-800-H. In addition, Ni@NC-800-H was efficient for the conversion of various lignin β-O-4 alcohol and ketone model compounds with methoxyl groups with high yields of the aromatic products and also possessed high stability during consecutive reaction runs, which is because Ni nanoparticles are physically isolated from the reactive environment.
研究领域:
化学工程
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催化材料
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可再生资源转化
✓ 已验证
DOI
高影响因子
Journal of CO2 Utilization
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2018
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IF 5.503
Yu Cao,Ran Ma,Ning Wang,Mei-Yan Wang,Xue-Dong Li,Liang-Nian He
Selective hydrogenolysis is a crucial challenge for lignin valorization. A PdCl 2 -catalyzed hydrogenolysis of C OH bond of various lignin β-O-4 alcohol model compounds was developed for preparation of corresponding phenethoxybenzene in 78–98% isolated yield. Notably, the introduction of low-pressure CO 2 (1 MPa) remarkably improves the reaction efficiency and selectivity of phenethoxybenzene. Neither over-reduction of aromatic ring nor further debenzylation was detected. This is understandable that the in situ methylcarbonic acid generated from CO 2 and methanol acts as an acidic catalyst and enhances the leaving ability of hydroxyl group of β-O-4 alcohols. Besides, the present PdCl 2 /CO 2 /MeOH catalyst system proved to be effective for reductive cleavage of C O bonds of β-O-4 ketones, producing ethylbenzenes accompanied with phenols in high yields. Furthermore, this protocol could also be extended to selective hydrodeoxygenation of the carbonyl group to methylene in aromatic ketones. As a sound reaction medium, such in situ CO 2 /MeOH acidic system could be inherently neutralized by depressurizing CO 2 , providing feature advantages for simple post-processing and none waste disposal.
研究领域:
化学
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催化反应
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生物质转化
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Jia-Qi Wu,Qing He,Zhuang-Zhuang Li,Si-Wen Li,Wei Wang,Jian-She Zhao
Lignin, a major component in renewable plant biomass, serves as a potential source of high-value aromatic chemicals. However, efficiently decomposing lignin while maintaining its aromaticity for fossil fuel substitution remains a significant challenge. This study synthesized a [VimAm]Br@POM@AC catalyst, composed of a Keggin-type polyoxometalate (POM) modified by ionic liquid ([VimAm]Br) and supported on activated carbon (AC). The response-surface methodology was applied to explore the catalytic performance of this catalyst in the oxidative depolymerization of lignin β-O-4 model compounds. Under the reaction conditions of 160 °C, 3 mL H 2 O 2 , and 0.4 g catalyst within 8 h, the conversion rate of lignin model compounds reached 83.01 %. The reaction generated diverse aromatic products, with the selectivity of methyl mandelate and methyl benzoate reaching 27.70 % and 59.02 %, respectively. Mechanistic studies revealed that the [VimAm]Br@POM@AC catalyst selectively cleaves C O bonds in β-O-4 dimers, facilitating the formation of aromatic compounds. Moreover, FT-IR spectroscopy and SEM analysis confirmed the good stability of the recovered catalyst. This work achieves efficient directional conversion of lignin model compounds through the design of a multilevel-structured catalyst, precise optimization of reaction conditions, and innovative mechanistic interpretation. It offers a novel strategy with both academic significance and application potential for the high-value utilization of biomass resources.
研究领域:
催化
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绿色化学
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生物质转化
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材料科学
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有机化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）