JOURNAL OF CATALYSIS
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2017
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IF 6.844
Huifang Liu,Min Wang,Hongji Li,Nengchao Luo,Shutao Xu,Feng Wang
Catalytic oxidation of C C bond is a key technology to transform petroleum-based as well as sustainable biomass feedstock into more valuable oxygenates. We herein describe a convenient and useful oxidation strategy of converting ketones into carboxylic acids using homogeneous copper catalyst without additives and with O 2 as the terminal oxidant. A wide range of aryl and aliphatic ketones as well as β–O–4 lignin models were selectively oxidized to acids via C C bond cleavage. Mechanism studies by EPR and in situ NMR elucidate the principles of Cu/O 2 reactivity that involves C H bond and O 2 activation via a peroxide species. This provides an important foundation for expanding the scope of useful aerobic oxidation reactions using copper catalysts.
研究领域:
有机化学
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催化化学
✓ 已验证
DOI
高影响因子
STAR Protocols
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2022
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IF 0
Fukai Xie,Hongliang Liang,Wen Dai
Summary The cleavage and functionalization of carbon-carbon (C–C) bonds has emerged as a powerful tool for preparing value-added chemicals. In this protocol, we describe the preparation of amorphous manganese oxide and its application as a heterogeneous catalyst in the direct synthesis of amides via successive cleavage and amidation of C–C bonds in alcohols. Furthermore, we describe how a slight modification of reaction conditions allows for the cleavage and cyanation of alcohols to access sterically hindered nitriles. For complete details on the use and execution of this protocol, please refer to He et al. (2022) .
研究领域:
化学
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催化科学
✓ 已验证
DOI
PubMed
Journal of Materials Chemistry A
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2022
·Vol. 10
·期 20
·11268-11276
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IF 14.511
Jiabao Guo,Yizhuo Zhao,Peng Wang,Yang Song,Yifei Shao,Li Zhu,Xiaoquan Yao
Catalytic selective cleavage reaction of the C(sp3)–C(sp3) bond has received little attention, despite its importance in organic synthesis and biochemistry. Herein, a novel copper loaded nitrogen-rich mesoporous carbon nitride material was designed and synthesized, and utilized as a highly efficient photocatalyst for the inert C–C bond cleavage of amines under blue light irradiation. With oxygen as a benign oxidant, good to excellent yields were achieved for various functionalized amines at room temperature, even including sluggish aliphatic amines. The method may provide a cost-effective and environmentally friendly alternative for the direct oxidative cleavage of amines.
研究领域:
有机合成
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光催化化学
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材料科学
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
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2015
·Vol. 17
·期 11
·4968-4973
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IF 8.02
Yangyang Ma,Zhongtian Du,Junxia Liu,Fei Xia,Jie Xu
Selective transformation of lignin into value-added aromatics is highly attractive and rather challenging. Catalytic oxidative degradation provides a promising approach to obtain aromatics from lignin while preserving the benzene units. In this study, vanadium-catalyzed aerobic oxidation of 2-phenoxy-1-phenylethanol was studied as a lignin model compound. The solvent played a significant role in the distribution of oxidation products. In the presence of acetic acid, oxidative C–C bond cleavage was preferred, while oxidation products via C–H bond cleavage were rather limited. A one-electron transfer process was involved in the oxidation reaction. The occurrence of vanadium(V) was detected, and the carboxylic group could coordinate to vanadium(V) through exchange with the acetylacetonato ligand during oxidation in the presence of acetic acid.
研究领域:
化学
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催化科学
✓ 已验证
DOI
高影响因子
ChemCatChem
·
2016
·Vol. 8
·期 11
·1929-1936
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IF 4.724
Bin Chen,Bin Zhang,Yibo Zhang,Xiangguang Yang
Graphical Save it for a Raney day : A series of Ag-modified Ni catalysts is prepared, and the role of bimetallic effects on the selective cleavage of C−O and C−C bonds is investigated in glycerol hydrogenolysis, a model reaction for the utilization of biomass-derived polyols. Compared to Raney Ni, the optimal Raney Ni 6 Ag catalyst is more active in glycerol conversion and efficient for C−O bond cleavage to afford a higher selectivity toward C 3 products. A series of Ag-modified Ni catalysts was prepared, and the role of bimetallic effects on the selective cleavage of C−O and C−C bonds was investigated in glycerol hydrogenolysis, a model reaction for the utilization of biomass-derived polyols. Compared to Raney Ni, the optimal Raney Ni 6 Ag catalyst was more active in glycerol conversion and efficient for C−O bond cleavage to afford a higher selectivity toward C 3 products (1,2-propanediol and lactic acid; 88 %) at the same ∼70 % conversion of glycerol, especially 1,2-propanediol (73 %). On Ni catalysts, the hydrogenation of adsorbed species was the most likely rate-limiting step in glycerol hydrogenolysis under alkaline conditions. The Ag additive enhanced the hydrogenation ability of Ni catalysts, which should be related to the higher strength of the adsorption of hydrogen and the lower strength of the adsorption of substrates on Ni sites because of the formation of Ni-Ag alloys. A mechanistic interpretation was presented for the excellent catalytic behavior.
研究领域:
催化化学
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生物质利用
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材料科学
✓ 已验证
DOI
高影响因子
BIOMASS & BIOENERGY
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2022
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IF 5.774
Jie Zhang,Danyang Cao,Shanshan Wang,Xin Feng,Jiahua Zhu,Xiaohua Lu,Liwen Mu
In this study, heteroelement-rich groups (N and B elements, tris (2-hydrazinylethyl) borate) were successfully synthesised on lignin by microwave amination. The reaction between lignin and heteroelement-rich groups was confirmed using several characterization techniques, including fourier transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) analysis, and X-ray photoelectron spectroscopy (XPS). A lignin model compound (2-phenoxyacetophenone (L-M)) was used to study the bond-breaking mechanism of lignin depolymerization , and the amine group, which acted as a nucleophile , attacked the C–C bond to form an amide bond with the lignin. As an effective additive, modified lignin can increase the viscosity of poly (ethylene glycol) 200 (PEG200), reducing the wear volume and friction coefficient in the friction test. Theoretical calculations showed that the polarity of the modified lignin increased, which allowed the modified lignin to form a strong physical adsorption on the metal surface. In addition, the reciprocal hydrogen bonding between the modified lignin and PEG200 contributes synergistically to the enhanced lubrication film strength , and thus, the better tribological properties of these new lubricants.
研究领域:
高分子化学
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材料科学
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绿色化学
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表面工程
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能源材料
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可持续技术
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
·
IF 11.698
Yi Liu,Yuliu Liu,Yi Zhang
Aqueous-phase hydrogenation of glucose to lower diols (ethylene glycol (EG), 1, 2-propylene glycol (PG), and butanediol (BDO)) over bi-functional Ru-W supported catalysts was investigated in a continuous-flow fixed-bed reactor. A variety of catalysts based on different supports including mesoporous SiO 2 , activated carbon (AC), carbon nanofibers (CNFs), and bulk WO 3 were compared and examined by N 2 physisorption, H 2 chemisorption, XRD, TEM, ICP, H 2 -TPR, in-situ / ex-situ XPS, NH 3 -TPD, and Raman spectra. The results indicate that the lower diols yield is highly dependent on the synergistic effect of Ru metal sites and WO x acid sites, in other words, strongly depending on the competitive reactions of the glucose. Abundant W 4+ and Ru° sites on Ru-W/SiO 2 catalysts with large specific surface area effectively catalyze the selective cleavage of the C C bonds in glucose and subsequent hydrogenation to lower diols, resulting in 100% glucose conversion as well as highest diols selectivity (87.3%) over 50 h reaction at 478 K and 4 MPa H 2 . Meanwhile, the Ru/WO 3 with much lower surface area forms more W 5+ species, which is advantageous to producing more EG products (55.9%) at the same reaction conditions.
研究领域:
催化化学
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生物质转化
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绿色化学
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多相催化
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能源化工
✓ 已验证
DOI
高影响因子
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