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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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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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
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DOI
高影响因子
FUEL
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2022
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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
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产品关联
DOI
高影响因子
CHEMICAL PHYSICS LETTERS
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2022
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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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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
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DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Jinghu Chen,Mingming Wang,Shude Zhang,Yaju Wang,Jingfeng Hua,Xiangtong Meng,Qineng Xia,Jieshan Qiu,Shaomin Liu
Glycerol hydrogenolysis to 1,3-propanediol (1,3-PDO) is of significance in promoting the biomass valorization. To achieve the efficient conversion, the selective activation of the secondary C–O bonds in the glycerol is vital. In this work, we comparatively investigated the catalytic performances of Pt/Nb 2 W 3 O 14 catalyst for glycerol hydrogenolysis controlled at the reacting conditions of 140 °C and 40 bar. Compared to Pt/WO 3 and Pt/NbO x , the space–time yield (STY) of 1,3-PDO over Pt/Nb 2 W 3 O 14 catalyst can be improved by a factor of 13, reaching 596.4 mg g cat −1 h −1 . The cation ordering of Nb and W on atomic-scale were fully synergized their unique advantages, showing preferential adsorption of the secondary C–O bond under in-situ DRIFTS tracking. The prepared Nb 2 W 3 O 14 is a tetragonal tungsten bronze (TTB) type complex oxides which can effectively promote the dispersion and reduction of Pt nanoparticles. Such strong interaction between Nb 2 W 3 O 14 and Pt can coordinate the precise adsorption and activation of the secondary C–O bond, simultaneously triggering subsequent hydrogenation. Pt/Nb 2 W 3 O 14 affords an ultrahigh activity in glycerol hydrogenolysis to produce 1,3-PDO, tripling the record productivity that was previously reported of these Pt-W based catalysts. This study reported the development of highly synergistic catalyst based on efficient and selective activation of the secondary C–O bond, which can be extended to catalyst design for other biomass valorization.
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
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产品关联
DOI
高影响因子
FUEL
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2020
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IF 5.578
Tianjin Li,Hongfei Lin,Xinping Ouyang,Xueqing Qiu,Zechen Wan,Tao Ruan
The selective cleavage of C–O bond in lignin is the key to convert them into aromatic compounds and then to produce liquid fuels and chemicals. N-doped carbon nanosheets were obtained by direct pyrolysis of glucosamine hydrochloride (GAH) and melamine. Highly-dispersed and small-sized Ru nanoparticles (NPs) supported N-doped carbon by impregnation method, which can efficiently convert lignin to obtain 40.70% aromatic monomers. It was 2.3 times than that of the commercial catalyst (Ru/C) and the catalyst could be used at least five runs with an insignificant loss in the yield of aromatic monomers. The morphology, specific surface area, nitrogen species and content of supports could be tuned by controlling the weight of melamine. The results showed that the melamine and GAH were condensed to form layered graphitic carbon nitride (g-C 3 N 4 ) and a carbon skeleton at 600 °C, respectively. Then, the produced N from the decomposition of g-C 3 N 4 at high temperature (>700 °C) could improve nitrogen concentration, increase the specific area and result in the graphene-like wrinkled morphology. The presence of pyridinic N not only served as metal coordination sites to stabilize and disperse Ru NPs but also enhanced the proportions of Ru 0 through the electronic interactions. The DFT calculations implied that the pyridinic N contributed to the highest adsorption energy for 2-phenoxy-1-phenethanol (PPE) and a reduction of the disassociation energy for C alkyl –O bond compared with graphite N and pure C.
研究领域:
化学工程
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催化材料
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产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2018
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IF 6.759
Huihuang Fang,Alberto Roldan,Chenchen Tian,Yanping Zheng,Xinping Duan,Kun Chen,Linmin Ye,Stefano Leoni,Youzhu Yuan
Tungsten carbides exhibit excellent performance in many heterogeneous processes because of their distinctive catalytic properties. Preparation of tungsten carbides with controllable phase composition relevant to their catalytic behavior is essential yet challenging. In this study, tungsten carbides embedded in carbon spheres (W x C@CS) were fabricated through carburization of organic–inorganic hybrid precursors. W 1.25 C@CS with rational structure-tuning properties exhibits promising regioselectivity (reaching 91.5%) toward aryl C O bond cleavage, specifically during hydrogenolysis of guaiacol to phenol. A structure reconstruction strategy was adopted to elucidate structure–performance relationship by transforming commercially available bulk WC from inert phase to composition-dependent active catalysts. Combined catalytic and characteristic analyses illustrate that the catalyst performance is dependent on the C-defect structure. The intimate connection between the phenol space time yield and the C/W atomic ratio on the exterior interface of the catalyst was verified. The C/W atomic ratio of 7.2 leads to the optimal catalytic performance. Density functional theory calculations were performed to define the catalytic mechanism at the atomic level. The theoretical analysis suggests an appropriate configuration of surface W and C atoms for activation of hydrogen and guaiacol molecules, rendering the intrinsic active sites for phenol production. This work provides insights into controlling the surface compositions of tungsten carbides to develop efficient C O bond cleavage catalysts, which verifies the importance of hydrogenolysis catalysis in lignin-derived compounds involving complex O-containing guaiacols and phenolics.
研究领域:
化学工程
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催化科学
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材料科学
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产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
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2013
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IF 2.915
Shuai Leng,Xinde Wang,Xiaobo He,Lin Liu,Yue'e Liu,Xing Zhong,Guilin Zhuang,Jian-guo Wang
NiFe bimetallic catalyst shows an excellent activity and selectivity for the hydrodeoxygenation (HDO) of three typical model compounds of bio-oil. The conversion of furfuryl alcohol, benzene alcohol and ethyl oenanthate is 100, 95.48 and 97.89% at 400 °C and the yield to 2-methylfuran, toluene and heptane is 98.85, 93.49 and 96.11% at 0.1 ml/min flow speed and atmospheric pressure. It indicates that the major reaction pathway is the cleavage of C–O rather than C–C. After the catalytic HDO of bio-oil over NiFe/Al 2 O 3 catalyst, the heating value changes from 37.8 to 43.9 MJ/kg, the pH changes from 6.65 to 7.50.
研究领域:
能源化学
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催化化学
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产品关联
DOI
高影响因子
ACS Catalysis
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2022
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IF 13.7
Liang Jiang,Guangyue Xu,Yao Fu
The conversion of lignin into value-added chemicals is one of the important ways for sustainable development. Herein, phytic acid, a biomass-derived chemical, was used as the phosphorus source and pore former to synthesize the AlPyOx support. After loading Ni, the Ni/AlPyOx catalysts were found to be highly active in the catalytic conversion of lignin model compounds to high-value-added chemicals under mild conditions. The benzyl phenyl ether (α-O-4 lignin model compound) could be completely converted into toluene and phenol with near-equivalent selectivity at 30 °C and 3 MPa H2. Diphenyl ether and 2-phenoxy-1-phenylethanol were also used as 4-O-5 and β-O-4 model compounds of lignin, respectively. The unique activity of Ni/AlP0.5Ox could be attributed to metallic Ni that interacts with AlP0.5Ox and the unique adsorption of substrates on the carrier. Lignin can also be degraded over Ni/AlP0.5Ox via selective cleavage of the C–O bond, and 26.60 wt % yield of identified monomers was obtained.
研究领域:
催化化学
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生物质能
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可持续发展
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
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2023
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IF 7.5
Fa-Peng Wu,Yun-Peng Zhao,Zong-Pin Fu,Le-Le Qiu,Jian Xiao,Jian Li,Fang-Jing Liu,Jing-Pei Cao
Efficient transfer hydrogenolysis of benzyl phenyl ether (BPE) was accomplished over Ni 1.5 Cu 1.5 /Al 2 O 3 using isopropanol as hydrogen source . The characterization results demonstrated that the formation of NiCu alloy and electron transfer between Ni and Cu were responsible for the excellent catalytic performance. Isopropanol displayed better hydrogen-donating ability than other low-carbon alcohols because of its unique dehydrogenation pathway and small steric hindrance . The results of isotopic experiments elucidated that active hydrogen species for the C O bond cleavage originated from isopropanol rather than H 2 , while both isopropanol and H 2 were responsible for hydrogenation of phenol to cyclohexanol when reaction was conducted with mixed hydrogen sources. A mechanism study illustrated that transfer hydrogenolysis of BPE proceeded through direct cleavage of C O bond followed by phenol hydrogenation, in which the active hydrogen species were in the form of H + and H − .
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）