RSC Advances
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2016
·Vol. 6
·期 76
·72744-72749
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IF 3.289
Fei Xia,Zhongtian Du,Junxia Liu,Yangyang Ma,Jie Xu
Recently, obtaining value-added chemicals from biomass resources has attracted considerable attention. Levulinic acid is one of the most important biomass platform compounds, which could be obtained from carbohydrate biomass. In this work, levulinic acid was selectively converted into C4 product, including succinic anhydride, via catalytic oxidation with a manganese catalyst in acetic anhydride. Moreover, an unexpected product of maleic anhydride was obtained, which greatly differs from that of levulinate ester. The pathway for formation of maleic anhydride was studied by monitoring and confirming intermediates α-angelica lactone and its derivative 2-methyl-5-oxotetrahydro-2-furanyl acetate. Based on the obtained mechanistic information, the different behaviour between the oxidative cleavage of levulinic acid and levulinate ester was further discussed.
研究领域:
化学工程
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可再生资源化学
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DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
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2023
·
IF 3.8
Peng Xiong,Tong-Wei Zhang,Shi-Ming Li,Mei-Yu Xu,Guang-Ming -Liang,Liu-Cheng Gui,Xiu-Jian Wang
Two tetranuclear copper cages with tubular type, [Cu 4 (BMBA) 4 ((CH 3 ) 2 N) 2 (H 2 O) 2 ] ( 1 ) and [Cu 4 (BMBA) 4 (Bipy)(H 2 O) 2 ] ( 2 ), were successfully constructed by the reaction of Cu(NO 3 ) 2 with dicarboxylic acid 4,4′-[( ethylazanediyl ) bis ( methylene )]-bis[(1,1′-biphenyl)-2-carboxylic acid] (H 2 BMBA) under solvothermal conditions. The complexes 1 and 2 exhibit a similar cage structure, formed by four ligands connecting two binuclear copper paddle-wheel secondary building units (SBUs). Interestingly, the complex 2 was obtained by appropriately binding of 4, 4′-bipyridine (Bipy) molecule on the axial positions of two Cu paddle-wheels inside the cage. For this reason, the complex 2 exhibits excellent stability in some common organic solvents at room temperature and aqueous solutions with a pH of 2 to 12. Upon thermal activation of complex 2 , the coordinated water molecules can be removed, and its exposed metal active-sites show Lewis acid character, which can be used an efficient heterogeneous catalysis of Knoevenagel condensation (C C) and Clauson-Kaas (C N) reactions.
研究领域:
化学
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材料科学
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催化反应
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2025
·
IF 9
Song Han,Yun Zhao,Mina Liang,Jinshui Su,Xiangxiong Zhai,Qi Zhang,Guoling Li,Zhonghai Ni
The photocatalytic cleavage of C α -C β bonds in lignin holds considerable potential for the production of value-added chemicals. Lignin consists of phenylpropane units interconnected by a variety of complex chemical bonds. Specifically, C-O bonds are more prevalent and relatively easier to cleave, whereas C–C bonds exhibit higher bond energy, rendering them more difficult to cleavage under conventional conditions. This study presents a phosphotungstic acid/phosphoric acid-functionalized porous tubular C 3 N 4 composite photocatalyst (PW/P-TCN). H 3 PO 4 modified PW/P-TCN surfaces enhance O 2 adsorption, improve separation and transfer of photogenerated carriers, and increase exposure of active sites. This promotes reactant adsorption and significantly boosts photocatalytic efficiency. Through this strategy, 1,2-diphenylethanol (DPol), used as a typical model substrate, is fully converted into aromatic monomers, achieving a DPol conversion rate of 99.9 %. Mechanistic studies reveal that C α -C β bond cleavage primarily involves the photo-oxidation mechanism mediated by electron-hole coupling. The construction of the PW/P-TCN heterojunction is essential for simultaneously sustaining robust reduction and oxidation capabilities. Natural lignin samples are applied to the photocatalytic system, and successful C–C bond cleavage depolymerization is achieved under optimal reaction conditions. This study offers valuable insights for the design of more economical and efficient photocatalysts for lignin depolymerization.
研究领域:
材料科学
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环境科学
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化学工程
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DOI
高影响因子
BIOMACROMOLECULES
·
2020
·
IF 6.092
Caicai Jiao,Lilong Gao,Hui Zhang,Bing Yu,Hailin Cong,Youqing Shen
Hydrogels have a wide range of applications in the fields of biomedicine, flexible electronics, and bionics. In this study, injectable and self-healable hydrogels were first prepared based on a dynamic covalent C═C bond formed via the Knoevenagel condensation reaction between poly(ethylene glycol) dicyanoacetate and water-soluble poly(vanillin acrylate). Three kinds of catalysts (phosphate buffer, zeolitic imidazolate framework-8, and tertiary amine) were used in Knoevenagel condensation for preparing hydrogels. All hydrogels in this study could be formed in situ, and their gelation time ranged from seconds to minutes. The properties and application of hydrogels could be customized according to the type of catalyst employed. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) results indicated that all the components and hydrogels exhibited low toxicity, and the hydrogels could be used as 3D cell culture scaffolds. Because of the dynamic covalent C═C bond formed by Knoevenagel condensation, the resultant hydrogels were found to be dynamic and showed good self-healing properties. This work presents a new dynamic covalent chemistry for the preparation of self-healable materials.
研究领域:
生物医学工程
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材料科学
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组织工程
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DOI
PubMed
高影响因子
Journal of Physical Chemistry C
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2025
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IF 3.2
Xiang Chen,Shaohua Chen,Pengxin Liu,Chaodan Pu
We report the efficient C–C coupling between benzyl alcohol and benzaldehyde to hydrobenzoin using CdSe/CdS quantum dots as visible-light photocatalysts and sodium oxide as a cocatalyst. The optimized conditions resulted in a reaction with a selectivity of hydrobenzoin >95%, an apparent quantum yield of 23.6% under the excitation by 520 nm LED, and a turnover frequency of 56.8 mmol g–1 h–1. Reactant concentration-dependent experiments demonstrated that benzaldehyde can process fast proton-coupled electron transfer, improving the utilization of photogenerated electrons. Photoluminescence quenching experiments and reactions with deuterated benzaldehyde confirmed that due to the in situ produced hydrogen ions, the hydroxymethyl radicals would process efficient reverse conversion from hydroxymethyl radicals to benzyl alcohol, resulting in noneffective charge transfer. Formation of sodium benzyloxide can eliminate the in situ produced hydrogen ions around the hydroxymethyl radical, suppressing this reverse conversion and improving the utilization efficiency of transferred holes and electrons.
研究领域:
化学
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材料科学
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DOI
高影响因子
ANALYST
·
2022
·Vol. 147
·期 7
·1341-1347
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IF 5.227
Chen-Chen Jiang,Xiao-Chong Li,Jian-Ang Fan,Jia-Ying Fu,Xu-Nan Huang-Fu,Jia-Jie Li,Ju-Fang Zheng,Xiao-Shun Zhou,Ya-Hao Wang
The electroreductive cleavage of carbon–halogen bonds has attracted increasing attention in both electrosynthesis and pollution remediation. Herein, by employing the in situ electrochemical shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) technique, we have successfully investigated the electroreductive dehalogenation process of aryl halides with the thiol group on a smooth Au electrode in aqueous solution at different pH values. The obtained potential-dependent Raman spectra directly reveal a mixture of the reduction products 4,4′-biphenyldithiol (BPDT) and thiophenol (TP). The conversion ratios of the C–Cl and C–Br bonds at pH = 7 are 37% and 55%, respectively. Furthermore, quantitative analysis of the intensity variations of ν(C–Cl), ν(C–Br) and aromatic ν(CC) stretching modes suggests electroreductive dehalogenation via both direct electron transfer reduction and electrocatalytic hydrodehalogenation. Molecular evidence for the C–C cross coupling process through TP reaction with benzene free radical intermediates is found at negative potentials, which leads to the increasing selectivity of biphenyl products.
研究领域:
电化学
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材料科学
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环境科学
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DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
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2022
·
IF 8.008
Fangling Wu,Xishi Wu,Chaoxian Chi,Chuan-Fan Ding
Fatty acids play a pivotal role in biological processes and have many isomers, particularly at the C═C position, that influence their biological function. Distinguishing between isomers is crucial to investigating their role in health and disease. However, separating the isomers poses a significant analytical challenge. In this study, we developed a simple and rapid strategy combining ion mobility spectrometry and theoretical chemical calculations to differentiate and quantify the C═C positional isomers in 2-/3-butenoic acid (BA), 2-/3-/4-pentenoic acid (PA), and 2-/3-/5-hexenoic acid (HA). C═C positional isomerism was mobility-differentiated by simple complexation with crown ethers (12C4, 15C5, and 18C6) and divalent metal ions (Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Sr2+, and Ba2+), that is, converting C═C positional isomers with small structural differences into complexes with large structural differences through the interaction with metal ions and crown ethers. Metallized isomers were formed but could not be differentiated due to their complex and overlapping extracted ion mobiliograms (EIMs). Binary crown ether–isomer complexes were not observed, indicating that C═C positional isomers could not be separated by simple mixing with crown ethers. However, significant EIM differences were obtained for the formed ternary complexes, allowing baseline separation for the isomers. Notably, all crown ethers and metal ions have a separation effect with the isomers, with a calculated separation resolution (Rp–p) of 0.07–2.44. Theoretical chemical calculations were performed to provide in-depth structural information for the complexes and explain the separation principle. Theoretical conformational space showed that the divalent metal ions act as a bridge connecting the crown ether and the isomer. Additionally, the ternary complex becomes more compact as the distance between C═C and −COOH increases. Theoretical results can reflect the features of mobility experiments, with relative errors between the experiment collision cross-section (CCS) and theoretical CCS of no more than ±8.06%. This method was also evaluated in terms of quantification, accuracy, and precision repeatability. Overall, this study establishes that the crown ether–metal ion pair can function as a robust unit for differentiating C═C positional isomerism.
研究领域:
分析化学
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生物化学
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DOI
PubMed
高影响因子
Molecular Catalysis
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2025
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IF 4.9
Wei Wang,Rui Zhang,Jiaqing Li,Huai Liu,Wenlong Jia,Junhua Zhang,Dan Li,Lincai Peng
Furans are important scaffolds with applications in pharmaceuticals, polymers synthesis and biofuels. The direct production of new types of furans from glucose is therefore significant but remains a great challenge. Herein, we report a facile strategy to produce acetylfurans directly from glucose over MoCs-SiO 2 , with an increase in yield from 35.8 % to 81.4 % compared with pristine Mo-SiO 2 due to the facilitated C−C bond cleavage of glucose. The incorporation of Cs improved the dispersion of Mo species, induced the formation of partially reduced Mo, increased the Lewis acidity and glucose adsorption of the catalyst, and thus shifting the reaction selectivity from C−C coupling to cleavage. Kinetic studies further demonstrated the positive contribution of Cs as a promoter in lowering the activation energy of C−C bond cleavage. This study provides a promising strategy to broaden the range of furanic compounds derived from glucose for product-oriented biorefineries.
研究领域:
化学工程
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生物催化
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可再生资源利用
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高影响因子
GREEN CHEMISTRY
·
2023
·Vol. 25
·期 13
·5150-5159
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IF 9.8
Yuzhen Hu,Yanbin Cui,Shuoxiao Zhao,Xuelai Zhao,Xiaohong Hu,Zhenlong Song,Wei Fan,Qi Zhang
Selective cleavage of C–C bonds in the lignin structure is crucial for the depolymerization of lignin and producing value-added chemicals. In this study, we reported that Pd/CeO2 catalysts can selectively catalyze the Cα–Cβ bond cleavage of oxidized lignin model components and authentic lignin in an aqueous phase under mild conditions (50 °C, ambient pressure). A variety of β-O-4 and β-1 ketones with representative Cα–Cβ bonds were successfully cleaved yielding aromatic acids and phenols in 76.8–94.9% yields. Their unique catalytic properties are derived from the electron transfer between Pd and CeO2 support which facilitates active Pd2+ sites and reactive oxygen species formation. A mechanistic study elucidates that base-mediated C–H bond activation via enolization and in situ reactive oxygen species (˙O2−) formation are the key steps for the selective Cα–Cβ cleavage. Furthermore, the applicability of the system for the bond cleavage in an authentic lignin sample was demonstrated. Nearly 54.2 wt% of oxidized bamboo lignin was converted, generating aromatic monomer yields up to 35.9 wt%, with a high selectivity for aromatic aldehydes.
研究领域:
化学工程
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催化科学
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DOI
高影响因子
ACS Catalysis
·
2021
·
IF 13.084
Yuebing Xu,Wenda Yu,Hao Zhang,Jian Xin,Xiaohui He,Bing Liu,Feng Jiang,Xiaohao Liu
Various Co-based SAPO-34 catalysts were prepared using different methods, including ion exchange (IE), incipient-wetness impregnation (IWI), and solid-phase grinding (SPG), to correlate the chemical states of Co species with the C–H and C–C bond scissions in ethane dehydrogenation. The IE-prepared Co/SAPO-34 led to stable, unreducible, and isolated exchanged Co sites anchored on the zeolite framework with a structure of −AlF–O–Co–O– and showed the highest selectivity to ethylene of close to 98% at 600 °C, which suggests that these Co sites favors suppressing the C–C bond scission in ethane. In comparison, the IWI- and SPG-prepared Co/SAPO-34 catalysts, especially for those with a high Co loading, inevitably give Co oxide clusters that are easily reduced into metallic Co. Together with catalytic results, characterizations, and DFT calculations, it is confirmed that the reduced Co clusters, especially for those outside SAPO-34 channels without the confinement effect, favor both C–H and C–C bond scission, boosting the conversion of ethane into CH4 or/and coke; however, the ionic-state −Co–O– species can smoothly terminate the ethane dehydrogenation for the ethylene product due to relatively high energy barriers for both C–H and C–C bond scission, avoiding a deep dehydrogenation and C–C cracking. As expected, the unreducible −Co–O– sites are very stable in the title reaction without deanchoring from the zeolite framework in a 100 h cyclic test. This study not only demonstrates the stable −Mδ+–Oδ− structure favorable for suppressing C–C bond scission but also highlights a catalyst-constructing strategy for Co-based and similar metal-based catalysts for dehydrogenation of other light alkanes.
研究领域:
催化化学
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材料科学
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计算化学
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DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2022
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IF 9.224
Jiayuan Sun,Shanshan Shao,Xinggang Hu,Xiaohua Li,Huiyan Zhang
The aqueous fraction of bio-oil from biomass fast pyrolysis mainly contains low-molecular-weight oxygenates such as carboxylic acids, ketones, aldehydes, phenols, and furans. In this study, the full components of aqueous bio-oil are directionally converted into carbonyl groups such as aldehydes and ketones, and then the oxygen-containing precursors of aviation fuel are prepared through coupling, focusing on exploring the mechanism of carbonylation and C–C coupling. Studies have revealed that propionic acid, furfural, and phenol can be directionally converted into ketones, in which reaction 3-pentanone, cyclopentanone, and cyclohexanone were formed via ketonization and hydrogenation in the aqueous phase. Then the two components of 3-pentanone, cyclopentanone, cyclohexanone, acetone, and acetaldehyde were subjected to aldol condensation to explore the C–C coupling mechanism in the preparation of the C7–C18 precursor of aviation fuel. The mechanism in the high-quality utilization of all components of the aqueous phase bio-oil fraction was explored, which was favorable for the synthesis of biomass-based aviation fuel.
研究领域:
化学工程
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可再生能源
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生物质转化
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DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2018
·Vol. 56
·期 20
·2344-2353
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IF 2.588
Jiajun Bi,Jian Chen,Yahao Dong,Wen Guo,Dajian Zhu,Tao Li
A new polymer was prepared from 1,3,5-triformylphloroglucinol (noted as TDTB) and o -phenylenediamine through Schiff base condensation reaction, and palladium (II) was immobilized on the polymer (noted as TbPo-Pd(II)). This process was easy to work-up and cost-effective. The structure and composition of TbPo-Pd(II) were fully characterized by FTIR, TGA, XPS, AAS, SEM, and TEM analyses. Meanwhile, this catalyst showed desired thermal stability and excellent performance in water/methanol system for Suzuki and Sonogashira coupling reactions. In addition, this heterogeneous catalyst can be readily recovered by simple filtration with no appreciable Pd leaching in the reaction. This work provides a powerful protocol for rapid access to asymmetrical biphenyls and aryl alkynes. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56 , 2344–2353
研究领域:
有机化学
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材料科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）