ACS Sustainable Chemistry & Engineering
·
2022
·
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.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2023
·
IF 11.4
Yingying Zhou,Jia-jia Jiao,Huang Huang,Yong Dong Liu,Rugang Zhong,Xin Yang
Dichloroacetonitrile (DCAN) as one of the potentially prioritized regulated DBPs has drawn great attention; however, understanding its formation, especially the C–C bond cleavage mechanisms, is limited. In this study, DCAN formation mechanisms from long-chain primary amines, amino acids, and dipeptides during chlorination were investigated by a combined computational and experimental approach. The results indicate that nitriles initially generate for all of the above precursors, then they undergo β-C-hydroxylation or/and α-C-chlorination processes, and finally, DCAN is produced through the Cα–Cβ bond cleavage. For the first time, the underlying mechanism of the C–C bond cleavage was unraveled to be electron transfer from the O– anion into its attached C atom in the chlorinated nitriles, leading to the strongly polarized Cα–Cβ bond heterocleavage and DCAN– formation. Moreover, DCAN molar yields of precursors studied in the present work were found to be determined by their groups at the γ-site of the amino group, where the carbonyl group including −CO2–, −COR, and −CONHR, the aromatic group, and the −OH group can all dramatically facilitate DCAN formation by skipping over or promoting the time-consuming β-C-hydroxylation process and featuring relatively lower activation free energies in the C–C bond cleavage. Importantly, 4-amino-2-hydroxybutyric acid was revealed to possess the highest DCAN yield among all the known aliphatic long-chain precursors to date during chlorination. Additionally, enonitriles, (chloro-)isocyanates, and nitriles can be generated during DCAN formation and should be of concern due to their high toxicities.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2023
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IF 6.1
Wenwen Yang,Xiaoping Zhang,Jun Zhang,Guoshuan Wang,Hailong Liang,Xinglei Zhang,Konstantin Chingin,Huanwen Chen
The positions of C═C bonds in unsaturated fatty acids (FAs) are one of the main factors determining the quality of food flavor. Herein, we developed an approach for the determination of C═C bonds of FAs by online epoxidation reaction with water dimer radical cations. The limit of detection for octenoic acid isomers was ∼9 μg/L. The positions of C═C bonds in trans-2/3-hexenoic acid, trans-2/3-octenoic acid, oleic acid, linoleic acid, and linolenic acid in black tea or olive oil samples were directly determined by the established method. These results indicate that the established method allows the rapid determination of unsaturated FAs in black tea and olive oil. The advantages of this approach include the analysis speed (∼1 min per sample), simple device, and no need for complex pretreatment. This study not only provides a strategy for the determination of C═C positions but also offers new possibilities for applications in the field of food chemistry.
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TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2019
·
IF 2.338
Li-ping RAN,Fei RAO,Ke PENG,Huan YIN,Mao-zhong YI
Ultrahigh-temperature ceramics were added to C/C composites to meet their application requirement in a high-temperature oxidizing environment. C/C−ZrB 2 −SiC composites were fabricated by high-solid-loading slurry impregnation with polymer infiltration and pyrolysis. The dispersion and rheological behavior of ZrB 2 slurry and the microstructural, mechanical, and ablation properties of the C/C−ZrB 2 −SiC composites were investigated. Results indicated that a well-dispersed and low-viscosity ZrB 2 slurry was obtained using 0.40 wt.% polyethyleneimine as a dispersant at pH 5. Ceramics were uniformly distributed in the short-cut fiber layer and needle-punched area. The flexural strength of the C/C−ZrB 2 −SiC composites was 309.30 MPa. The composites exhibited satisfactory ablation resistance under the oxyacetylene flame of 2500 °C, and the mass and linear ablation rates were 0.40 mg/s and 0.91 μm/s, respectively. A continuous and compact ZrO 2 layer, which could effectively reduce the diffusion rate of oxygen and protect the composites from being ablated, was formed.
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Catalysts
·
2025
·Vol. 15
·期 3
·258
·
IF 4
Ling Xie,Zilong Huang,Yapeng Zhan,Jiahao Huang,Chao Wang,Riyang Shu,Junyao Wang,Libin Lei,Jianping Liu,Zhipeng Tian,Ying Chen
Cleavage of C-C bonds is crucial for hydrogen production via aqueous phase reforming of biomass-derived oxygenates. In this study, the hydrogen production performance and C-C bond cleavage capacity of Ni-W/AC catalysts with varying W/Ni ratios are evaluated using ethylene glycol as a model compound. A series of APR experiments conducted suggests that Ni-0.2W/AC catalyst exhibits the highest C1/C2+ratio of 15.87 and achieves a hydrogen yield of 47.76%. The enhanced Ni-W bimetallic interactions, which significantly improve the efficiency of C-C bond cleavage and increase catalyst activity by promoting active site dispersion, are confirmed by detailed characterization techniques. Further analysis of product distribution provides insights into the reaction pathways of ethylene glycol and the reaction mechanism for ethanol during aqueous phase reforming. All the results indicate that this catalytic reforming method effectively facilitates C-C bond cleavage and hydrogen production, contributing to a better understanding of APR mechanisms for biomass-derived oxygenates.
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Science China-Materials
·
2025
·
IF 7.4
Zhao Weidong,Zheng Mengfei,Chu Hongyu,Zhang Jingxuan,Wang Kun,Yang Chenguang,Shen Na,Tang Zhaohui
β-Lapachone (β-Lap) is a promising ortho -naphthoquinone drug for cancer treatment and has been in clinical trials. Its application is constrained by the low aqueous solubility, and severe side effects. Even prodrug designation is an effective approach to render it with tumor selectivity, it is limited by the lack of modifiable groups on β-Lap. Herein, a novel azo bond primary cleavage and carbon–carbon (C–C) bond secondary cleavage-based polymeric β-Lap prodrug (Azo-Lap NP) is designed, in which the self-immolated para -aminobenzyl linker is connected to poly( l -glutamic acid) (PGlu) via azo linkage and the responsive drug release of β-Lap against tumors can be achieved under high NAD(P)H:quinone oxidoreductase 1 (NQO1) expression and low pH environment in tumors. The effective covalent loading of β-Lap by Azo-Lap NPs permitted a high administration dose of β-Lap and enabled significant tumor retention time. Moreover, Azo-Lap NPs markedly reduced the side effects of β-Lap by avoiding hemolysis and the production of methemoglobin. The safety of Azo-Lap NPs administration is validated in the antitumor experiment of mice. In the 4T1 model, Azo-Lap NPs exhibited a markedly higher tumor suppression rate than β-Lap. This work provides an effective and safe polymeric prodrug for tumor selective delivery of β-Lap.
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CARBON
·
2024
·
IF 10.5
Hui Zhu,Bo Liu,Jiawang Hou,Ruiqi Wang,Ye Cong,Zhijun Dong,Baoliu Li,Jianguang Guo,Xuanke Li
Developing a nanoscale secondary thermal conduction network within carbon fiber performs is a challenging yet effective method to substantially enhance the thermal conductivity of C/C composites. In this study, a strategy for creating a three-dimensional (3D) SiC nanowires (SiCNWs) thermal conductivity network in carbon felts (CFs) was implemented using vacuum thermal evaporation technology to fabricate SiCNWs modified C/C composites (SiCNW–C/C). The growth mechanism of SiC nanowires within CFs and their impact on the microstructure and thermal conductivity of the C/C composite were thoroughly investigated. The findings indicate that a SiC nanowires thermal conduction network can be successfully established within carbon felts without catalysts by initiating nucleation sites and managing reaction pressure. An appropriate reaction pressure is crucial not only for the uniform growth of SiC nanowires but also as a key factor in modulating the content and microstructure of the SiC nanowires. SiC nanowires prepared at 150 Pa exhibit minimal structural defects and are evenly distributed throughout the carbon felts, markedly enhancing the thermal response rate of the felts. The thermal conductivity of these SiCNW-modified C/C composites, both parallel and perpendicular to the carbon fibers, increased to 173 W/m•K and 112 W/m•K, respectively, approximately tripling that of the pure C/C composite. The exceptional thermal management capabilities of SiCNW–C/C were empirically validated through simulated operational chips and finite element simulation. This work presents an effective approach for producing C/C composite with high thermal conductivity particularly through the thickness, offering promising applications in the thermal management of advanced electronics.
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CHINESE JOURNAL OF CATALYSIS
·
2025
·
IF 17.7
Xianlong Lu,Lili Wang,Xueyang Zhao,Binbin Pan,Zhendong Li,Xiangfei Du,Shihan Zhang,Fan Dong,Bangwei Deng
Copper (Cu)-based catalysts show significant potential for producing high value-added C 2+ products in electrocatalytic CO 2 /CO reduction reactions (CO (2) RR). However, the structural reconfiguration during operation poses substantial challenges in identifying the intrinsic catalytic active site, especially under similar mass transport conditions. Herein, three typical and commercial Cu-based catalysts (Cu, CuO, and Cu 2 O) are chosen as representatives to elucidate the structure-activity relationship of CORR in the membrane electrode assembly electrolyzer. Notably, only the Cu catalyst demonstrates the most suppression of hydrogen evolution reaction, thus achieving the highest FE of 86.7% for C 2+ products at a current density of 500 mA cm –2 and maintaining a stable electrolysis over 110 h at a current of 200 mA cm –2 . The influence of chemical valence state of Cu, electrochemical surface area, and local pH were firstly investigated and ruled out for the significant FE differences. Finally, based on the structure analysis from high resolution transmission electron microscope, OH – adsorption, in situ infrared spectroscopy and density functional theory calculations, it is suggested that the asymmetric C-C coupling ( via *CHO and *CO) is the most probable reaction pathway for forming C 2+ products, with Cu (100)-dominant grain boundaries (GBs) being the most favorable active sites. These findings provide deeper insights into the synergistic relationship between crystal facets and GBs in electrocatalytic systems.
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GREEN CHEMISTRY
·
2025
·
IF 9.2
Shilei Zhang,Hang Wang,Yang Wang,Min Zhang,Weimin Wang,Liang Zhang,Jun Li,Xun Zhu,Qian Fu,Qiang Liao
Elevating the operating pressure could significantly enhance CO2 accessibility on the catalyst in electrochemical CO2 reduction (CO2RR); however, achieving selective production of multi-carbon (C2+) products under pressurized conditions remains a critical challenge because elevated pressure could shift the selectivity towards C1 products. This work systemically investigated the variation of product selectivity induced by pressure and electrolyte composition, and demonstrates that a local pH drop induced by increased pressure is the key reason for hindered C–C coupling, as confirmed by in situ Raman and multi-physics simulation. The elevated pressure results in an increase of the electrolyte's buffering capacity, which neutralizes the alkaline microenvironment near the catalyst, thereby impeding the C–C coupling. Decreasing the buffering ability (using non-buffered KCl electrolyte) or increasing the current density (from 0.4 A cm−2 to 1.0 A cm−2) could maintain a high interfacial alkalinity under elevated pressure, promoting C–C coupling. By mapping pressure–current density operational windows, the optimal conditions were identified, achieving 70% C2 faradaic efficiency (50% for C2H4) at 5 bar and 1 A cm−2, demonstrating superior C2 product selectivity. This work establishes electrolyte engineering principles for industrial CO2RR, enabling carbon-neutral chemical production under practical pressurized conditions through microenvironmental regulation.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Yuanming Zhou,Shuxin Li,Shuangxing Zhu,Ruizhi Liu,Zhenxiao Tang,Maozhong Yi,Ke Peng
To investigate the influence of (Ta,Zr)C on the ablation resistance of C/C composites, C/C-(Ta 0.5 Zr 0.5 )C-SiC, C/C-(Ta 0.33 Zr 0.67 )C-SiC, and C/C-(Ta 0.2 Zr 0.8 )C-SiC were prepared with different Zr/Ta ratios through high-solid-loading slurry impregnation combined with precursor infiltration and pyrolysis. The flexural performance and ablation resistance both improved with an increasing Zr/Ta ratio. Compared to C/C-(Ta 0.5 Zr 0.5 )C-SiC and C/C-(Ta 0.33 Zr 0.67 )C-SiC, the flexural strength of C/C-(Ta 0.2 Zr 0.8 )C-SiC increased by 74.17 % and 24.29 %, respectively. The mass ablation rate was reduced by 74.33 % and 81.02 %, while the linear ablation rate was reduced by 98.60 % and 97.65 % after 120 s of ablation, respectively. The variations in Zr/Ta ratios affected the formation, integrity, and performance of the microstructure, which was composed of a Zr-rich oxide skeleton combined with Ta-rich oxide binder within the Ta-Zr-O oxide layer on the composite surface, ultimately enhancing the overall ablation resistance of these composites.
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Small
·
2025
·
IF 12.1
Zipei Cui,Yipeng Nie,Longquan Deng,Zhuo Li,Shuo Chen,Wenchao Sheng
Promoting C─C bond cleavage of ethanol to achieve a complete 12-electron pathway (C1 pathway) for ethanol oxidation reaction (EOR) is crucial for the development of highly efficient direct ethanol fuel cells. In this study, a highly porous ultrathin PdSn nanomesh (NM) with high proportion of low-coordinated edge and step sites is developed for alkaline EOR. The PdSn NM/C catalyst exhibited superior specific activity of 21.9 ± 0.9 mA cm −2 Pd with a significantly enhanced Faradaic efficiency of C1 pathway to CO 2 . In situ attenuated total reflection surface enhanced infrared absorption spectroscopy measurements demonstrated the significant enhancement of C1 selectivity on PdSn NM/C. Theoretical calculations further revealed the pivotal role of low-coordinated edge and step sites in effectively lowering the activation energy barrier for C─C bond cleavage of CH 3 CO*. This work provides a strategy for the rational design of highly efficient EOR electrocatalysts through low-coordinated site engineering.
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GREEN CHEMISTRY
·
2015
·Vol. 17
·期 11
·4968-4973
·
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.
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