JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2024
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IF 5.8
Yang-Yang Xu,Xing Fan,Feng-Yun Ma,Hai-Xu Zou,Xian-Yong Wei
Directly converting lignite into arenes as commodity chemicals and drop-in fuels is a highly desirable target for researchers. However, this is severely limited by the presence of stable inter unit C-O linkages in lignite. Herein, a highly active catalyst, Co-MoS 2 , has been designed and prepared to be used for the selective catalytic cleavage of inter unit C-O bridged bonds (BBs) in the conversion of Naomaohu (NMH), a lignite, to yield arenes. Both catalytic hydrogenation conversion (CHC) and thermal dissolution (a non-catalytic process, named NCHC) of NMH were conducted using n-hexane as the solvent. The soluble fractions from the first stage of NCHC (SF NCHC-1 ) and CHC (SF CHC-1 ), as well as the second stage of NCHC (SF NCHC-2 ) and CHC (SF CHC-2 ) were obtained using the same solvent. After the first-stage catalytic treatment, the relative contents of arenes and alkanes in SF CHC-1 increased by 16.7 % and 9.3 %, respectively, compared to those in SF NCHC-1 , and the relative content of oxygen-containing compounds (OCCs), such as alcohols, phenols , esters, ketones , acids, and furans, decreased by 13.2 %. For the second-stage conversion, the relative contents of arenes and alkanes in SF CHC-2 were 53.5 % and 15.5 % higher than those in SF NCHC-2 , and the relative contents of OCCs was only 6.6 % in SF CHC-2 . The catalytic mechanisms of cleavage of C-O BBs and deoxygenation were proposed based on the CHC of model compounds and density functional theory (DFT) calculation. The adsorption of OCCs and the activation of released hydrogen radical (H·) by Co-MoS 2 , followed by H· addition to the carbon atom connected to oxygen in C-O BBs and oxygen-containing functional groups, are crucial for the cleavage of C-O BBs and formation of deoxygenated compounds, particularly arenes.
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
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IF 3.8
Chuhan Zhang,Yanchang Chu,Linying Fu,Qiuyue Wang,Rui Ma,Donghai Xu,Le Yang
Lignin, a renewable resource rich in aromatic ring structures in nature, is an ideal natural source to produce aromatic compounds and cycloparaffin. Herein, we prepare MOF-derived Ni–MoxC/C and Co–MoxC/C as catalysts for the depolymerization of lignin and dimeric model compounds. Diphenyl ether (DPE) with 4-O-5 bond, benzyl phenyl ether (BPE) with α-O-4, and phenethyl phenyl ether (PPE) with β-O-4 are chosen as dimeric model compounds. Overall, Ni–MoxC/C and Co–MoxC/C show distinguished different activity toward product distribution. Ni–MoxC/C facilitates both C–O bond cleavage and hydrogenation of the benzene ring, and the main products are ethyl cyclohexane and cyclohexanol for all three model compounds. In contrast, Co–MoxC/C only facilitates C–O bond cleavage and obtains phenol and ethylbenzene as products. Similarly, for the depolymerization of lignin, cycloparaffins are obtained on Ni–MoxC/C, while phenol, guaiacol, 2,6-dimethoxyphenol, and their respective derivatives are obtained on Co–MoxC/C.
研究领域:
化学工程
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可再生资源利用
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产品关联
DOI
高影响因子
Catalysts
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2021
·Vol. 11
·期 3
·370
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IF 4.146
Yue Yang,Xiaochen Liu,Yuanjie Xu,Xing Gao,Yihu Dai,Yu Tang
Hydrodeoxygenation (HDO) is one of the promising catalytic routes for converting biomass derived molecules to high value products. A key step of HDO is the cleavage of an aromatic C–O bond to accomplish the deoxygenation step, however, which is energetically unfavorable. Herein, we report a series of palladium (Pd)-incorporated α-phase of molybdenum carbide (α-MoC) mesoporous composites for enhanced HDO activity of a biomass model molecule, anisole. The catalysts, x%Pd/α-MoC (x% is the molar ratio of Pd/Mo), were investigated by X-ray diffraction (XRD), temperature programmed reduction (TPR), temperature programmed desorption (TPD), Brunauer–Emmett–Teller (BET), Raman, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. Pd is highly dispersed on α-MoC when x% ≤ 1%, but aggregate to form nanoparticles when x% = 5%. The x%Pd/α-MoC catalysts (x% ≤ 1%) show enhanced HDO activity in terms of turnover frequency (TOF) and apparent activation energy barrier (Ea) compared with α-MoC and β-Mo2C catalysts. The TOF of 1%Pd/α-MoC catalyst at 160 °C is 0.115 h−1and the Ea is 48.2 kJ/mol. Moreover, the direct cleavage of aromatic C–O bond is preferred on 1%Pd/α-MoC catalyst. The enhanced HDO activity is attributed to superior H2dissociation ability by the highly dispersed Pd sites on carbide. This work brings new insights for rational design of the catalyst for selective C–O bond activation.Keywords:hydrodeoxygenation;carbide;palladium;anisole;biomass;C–O bond cleavage
研究领域:
催化
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化学工程
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材料科学
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DOI
高影响因子
JOURNAL OF CHEMICAL RESEARCH
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2021
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IF 0.782
Chun-Jing Li
We report a direct cross-coupling reaction between (het)aryl pivalates/tosylates and di(het)arylzinc species in 2-methyltetrahydrofuran/N-methyl pyrrolidone (1:1), which occurs via C–O bond cleavage under microwave irradiation. The reaction takes place smoothly in short reaction times without the addition of any catalyst or ligand. The reaction is suitable for a broad scope of substrates and exhibits good functional group compatibility, utilizes a simple work-up procedure, and gives the desired products in high purity.
研究领域:
有机化学
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合成化学
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DOI
高影响因子
FUEL
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2024
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IF 6.7
Yuqaio Ma,Xinping Ouyang,Lisha Zhao,Lifeng Li,Xueqing Qiu
The lignin-first strategy is a crucial approach for highly efficient depolymerization of lignin to produce aromatic monomers as the condensation of lignin occurred during the separating process which increased the difficulty in depolymerization. In this work, a cobalt atom clusters supported on nitrogen-doped carbon catalysts (Co/NC-15) was prepared by adjusting the dosage of melamine to control the morphology, structure, and pyridinic nitrogen content of the catalysts. DFT calculations based on lignin model showed that the doping of nitrogen increased the adsorption energy of the lignin on the supports and decreased the dissociation energy of C-O bonds. Under lignin first strategy, Co/NC-15 exhibited good ability to break C-O bonds at 220 °C of mild condition, in which 84.32 wt% of lignin in lignocellulosic biomass was converted into 40.62 wt% of aromatic monomers, while 84.02 wt% of cellulose was preserved. The atom clusters Co/NC-15 exhibited good catalytic activity to lignin depolymerization due to efficient cleavage of C-O bonds, and hence showed the promising prospect in potential industrial application.
研究领域:
生物化学
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催化化学
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产品关联
DOI
高影响因子
Molecular Catalysis
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2018
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IF 0
Jiang Li,Hui Sun,Jia-xing Liu,Jun-jie Zhang,Zhen-xing Li,Yao Fu
Lignin has recently attracted much attention as a promising resource to produce fuels and aromatic chemicals. The selective cleavage of C O bond while preserving the aromatic nature has become one of the major challenges in the catalytic valorization of lignin to aromatic chemicals. In this work, we report that the selective reductive cleavage of C O bond in lignin model compounds can be successfully achieved through heterogeneous iron catalysis. The hydrogenolysis of α-O-4 model linkage shows that the iron catalyst prepared by the simultaneous pyrolysis of iron acetate and 1,10-phenanthroline on activated carbon at 800 °C is the most active iron catalyst, affording phenol and toluene with yields of 95% and 90%, respectively. This aromatics selectivity is found to be much higher than that obtained over noble metal catalysts. The presence of N⋯Fe species as the active center of heterogeneous iron catalyst was confirmed by various technologies especially XPS and H 2 -TPR. For the β-O-4 model linkage, the vicinal OH group was essential for the iron-catalyzed hydrogenolysis of ether linkage. The oxidation of the α-carbon in the β-O-4 model compounds can significantly decrease the bond dissociation energy of ether linkage, giving depolymerization products in moderate to excellent yields.
研究领域:
催化化学
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可再生资源化学
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产品关联
DOI
ACS Catalysis
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2016
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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
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产品关联
DOI
高影响因子
ChemSusChem
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2016
·Vol. 9
·期 22
·3220-3229
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IF 7.116
Haiwei Guo,Bo Zhang,Changzhi Li,Chang Peng,Tao Dai,Haibo Xie,Aiqin Wang,Tao Zhang
Graphical Breaking up : Tungsten carbide shows remarkable activity in selective C−O bond cleavage of typical β-O-4 model compounds and deconstruction of lignin feedstocks. High yields of C−O cleavage products from model compounds (up to 96.8 %) and from lignin feedstock (up to 70.7 %) are obtained without destroying the aromatic rings. A remarkably effective method for the chemoselective cleavage of the C−O bonds of typical β-O-4 model compounds and the deconstruction of lignin feedstock was developed by using tungsten carbide as the catalyst. High yields of C−O cleavage products (up to 96.8 %) from model compounds and liquid oils (up to 70.7 %) from lignin feedstock were obtained under low hydrogen pressure (0.69 MPa) in methanol. The conversion efficiency was determined to a large extent by solvent effects and was also affected by both the electronic and steric effects of the lignin model compounds. In situ W 2 C/activated carbon (AC)-catalyzed hydrogen transfer from methanol to the substrate was proposed to be responsible for the high performance in methanol solvent. The conversion of 2-(2-methoxyphenoxy)-1-phenylethanol showed that the catalyst could be reused five times without a significant loss in activity for C−O bond cleavage, whereas the selectivity to value-added styrene increased markedly owing to partial oxidation of the W 2 C phase according to X-ray diffraction, Raman spectroscopy, and transmission electron microscopy characterization. 2 D-HSQC-NMR spectroscopy analysis showed that W 2 C/AC exhibited high activity not only for β-O-4 cleavage but also for the deconstruction of more resistant α-O-4 and β-β linkages, so that a high yield of liquid oil was obtained from lignin. Corn stalk lignin was more liable to be depolymerized than birch lignin owing to its loosened structure (scanning electron microscopy results), larger surface area (BET results), and lower molecular weight (gel-permeation chromatography results), whereas its liquid oil composition was more complicated than that of birch wood lignin in that the former lignin contained more p -hydroxyphenyl units and the former contained noncanonical units.
研究领域:
化学工程
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材料科学
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生物质能
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产品关联
DOI
PubMed
高影响因子
RSC Advances
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2015
·Vol. 5
·期 55
·43972-43977
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IF 3.84
Jun Hu,Dekui Shen,Shiliang Wu,Huiyan Zhang,Rui Xiao
The microwave-assisted cleavage of C–O linkages in benzyl phenyl ether was investigated at 200 °C in the presence of ZrP or SBA-15 doped with or without metal catalyst (Pd/C or Ru/C). The total yield of phenol and benzyl alcohol from benzyl phenyl ether depolymerization with ZrP was 26.91%, while the yield of phenol reached 26.11% for that with Pd/C. Hybrid catalysts performed effectively for promoting the formation of phenol. A conversion of 85.70% was achieved with ZrP–Pd/C catalyst, and the selectivity to phenol reached 47.32%. The highest yield of phenol was obtained at 1 h, and repolymerization was remarkable at longer reaction time. Based on the reaction using phenol and benzyl alcohol as the reactants, benzyl phenyl ether might be decomposed into phenol and benzyl alcohol following with the repolymerization producing thermally stable polymers in the presence of Pd.
研究领域:
化学工程
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Han-Bing Gao,Le-Le Qiu,Fa-Peng Wu,Jian Xiao,Yun-Peng Zhao,Jing Liang,Yong-Hui Bai,Fang-Jing Liu,Jing-Pei Cao
Catalytic hydrogenolysis of C O bonds in lignin provides a promising route to produce high value-added biofuels and chemicals. However, designing highly active and stable catalysts for this process is still a challenge. Herein, a series of Ni/Al 2 O 3 catalysts were synthesized by calcination and reduction of layered double hydroxide precursors, and their activities were evaluated in the catalytic conversion of lignin-derived compounds. Diphenyl ether was completely converted with a 100% monomeric selectivity (cyclohexane and cyclohexanol) over the optimized Ni/Al 2 O 3 -500 under the optimal conditions of 200 ℃, 0.5 MPa H 2 and 1.5 h, indicating the excellent catalytic activity in the cleavage of C O bonds of the catalyst. The excellent catalytic performances of Ni/Al 2 O 3 -500 were originated from its relatively large specific surface area, well-developed porosity, small crystallite size, high Ni 0 concentration and strong interaction between the active metal and support. The reusability experiments show that Ni/Al 2 O 3 -500 possesses a relatively high stability for six reuses. Moreover, various lignin model compounds can be completely converted to corresponding monomeric products over Ni/Al 2 O 3 -500, indicating the applicability of this ingenious catalyst. The application of the hydrotalcite-derived Ni-based catalysts with high activity and stability provides a promising approach for the efficient hydrogenolysis of lignin derivatives.
研究领域:
催化化学
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生物质转化
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL PHYSICS LETTERS
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2022
·
IF 2.719
Jie Xu,Feng Lin,Jingyu Wang,Yujie Wang
Photocatalytic cleavage of lignin C O bonds is a promising way to depolymerize lignin into aromatic value-added chemicals. However, the dispersibility of lignin in solvents and photocatalytic efficiency still face great challenges. Here, a micelle aqueous medium (CTAB-15) composed of hexadecyl trimethyl ammonium bromide and water was successfully prepared. 2-phenoxy-1-phenylethanol (lignin model compounds, PPol) and dioxanesolv poplar lignin have a good dispersion in CTAB-15. Compared to the previous reports, the highest photocatalytic efficiency can be obtained under optimal conditions by using the photocatalyst CdS. The main products formed by photocatalytic cleavage of lignin C O bonds are phenols and ketones. Mechanism studies show that CTAB-15 can provide sufficient hydrogen by photo-driven dissociation of water for photocatalytic cleavage of lignin C O bonds, which is critical to rapidly improving photocatalytic efficiency. The hydrogen, which is used to form acetophenone, comes from H 2 O and PPol. However, the hydrogen needed to form phenol comes only from PPol itself. In addition, the photocatalytic reaction follows a photogenerated electron-hole coupled redox process. This work develops a new direction for promoting the high-value utilization of lignin.
研究领域:
化学工程
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可再生资源利用
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产品关联
DOI
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
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2023
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IF 3.6
Benqiang Cui,Ye Tian,Yongchao Gao,Shaoyi Hua,Yanhui Shi,Changsheng Cao
Direct introduction of silyl radicals to forge C–Si bonds is of central importance in organic synthesis, owing to the formidable potential of silyl groups as coupling partners for further derivatization reactions to achieve more valuable compounds. Cleavage of heteroaromatic endocyclic carbon–heteroatom bonds to assemble C–Si bonds is scarce. Here, we demonstrate a dearomatization silylation of benzofurans and furopyridines via silyl radical addition and C(2)–O bond scission under metal-catalyst-free and mild conditions. Preliminary mechanistic experiments suggest that these transformations involve radical/single-electron transfer and [1,5]-Brook rearrangement processes. This protocol for the total synthesis of Doxepin and oxyresveratrol derivatives is carried out. The silylated products in several transformation reactions have proven to be useful as synthetic intermediates.
研究领域:
有机化学
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药物化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）