Journal of Renewable Materials
·
2021
·Vol. 9
·期 12
·2093-2117
·
IF 1.67
Li Rumeng,Zhan Guozhu,Ma Qi,Yang Yunhe,Liu Xiaoyun,Zhang Yitong,Zhuang Qixin
To explore the influence of substituent groups on thermally induced curing, eight new bio-based benzoxazines containing different substituent groups with different electron negativity and volumes were synthesized. The thermal curing of these bio-based benzoxazines was studied in detail.
Combined with the curing reaction kinetics, simulation and calculation of Highest Occupied Molecular and Lowest Unoccupied Molecular values, the spatial and electronic effects of different substituent groups on the curing of benzoxazine was explored. It was found that when the substituent
was located at the position directly connected to the N atom, the steric hindrance effect of the group was dominant. When the substituent group was located on the benzene ring connected to the O atom, both the electronic effect and the spatial effect influenced the curing of benzoxazine. When
an electron-withdrawing group was connected ortho position to the O atom, the curing reaction was promoted due to the decreased electron cloud density of O- on the oxazine ring, making the C-O bond easier to break. When an electron-donating group was connected to the meta position
of the O atom it also promoted the curing reaction, possibly because it increased the electron cloud density of the +CH2 reaction site and thereby facilitated electrophilic substitution via attack of +CH2 on the cross linking reaction centre. This
work provides a deeper understanding of how spatial and electronic effects of substituents affect the curing of benzoxazine.
研究领域:
材料科学
·
有机化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Jinqiu Ye,Tiancheng Ge,Xin Qu,Mohamedazeem M. Mohideen,Ce Wang,Ping Hu,Yong Liu
Dendrite growth and polarization are significant obstacles to the cycling stability of aqueous zinc-ion batteries (AZIBs). This work reports a zirconia-doped carbon nanofiber (ZrO 2 -CF) 3D scaffold fabricated via electrospinning and thermal treatment. Through electrochemical testing, physical Characterization, first-principles calculations, and finite element simulations, we analyzed the structure, mechanism, and performance of ZrO 2 -CF as a modified anode material. The unique 3D architecture of ZrO 2 -CF induces a “spatial effect,” offering a high specific surface area and excellent electronic pathways. Additionally, the “anchoring effect” of ZrO 2 , nitrogen-containing groups, and C O Zr and N Zr O bridges promotes uniform Zn deposition, enhances interfacial stability, and suppresses hydrogen evolution. The ZrO 2 -CF electrode achieves a high Coulombic efficiency of 98.6 % over 100 cycles and, in full cell, delivers initial capacities of 75 mAh g −1 at 1,000 mA g −1 and 124 mAh g −1 at 200 mA g −1 , with retention rates of 47 % and 76.8 % after 100 cycles, respectively. This study demonstrates the synergistic effects of “spatial” and “anchoring” mechanisms in mitigating dendrite growth and polarization, highlighting the potential of ZrO 2 -CF scaffolds for improving the overall performance of AZIBs.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Yuling Wang,Rongrong Pan,Depeng Jiang,Dechen Jiang,Hong-Yuan Chen
The chemical reaction in a confined space is known to be accelerated due to a high collision probability; however, the study of this confinement effect in a supersmall space down to femtoliter (fL) is seldom reported. Here, an adjustable volume [from picoliter (pL) to fL] of the aqueous phase is retrained at the tip of a nanopipette by an organic solvent so that the confinement effect on the specific activity of glucose oxidase is investigated. The activity is determined by the amount of hydrogen peroxide generated from the reaction between the oxidase and glucose using a nanoelectrode inside the nanopipette. As compared with the activity in bulk solution (82 U/mg), the activity increases up to 7500 U/mg in a 105 fL space. The 2 orders of magnitude increase in the enzymatic activity is the highest amplification in the volume-confined enzyme reaction as reported. A near-exponential drop in the activity is observed with the increase in the space volume, revealing the dominant enhancement in the confined space at the fL level for the first time. The established electrochemical nanopipettes should not only provide a strategy for the study of the enzymatic activity in supersmall confined space but also help understand the confinement effect of enzyme-catalyzed reactions.
研究领域:
生物化学
·
电化学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Zhe Xu,Yijie Wu,Qiuyi Ji,Taozhu Li,Chenmin Xu,Chengdu Qi,Huan He,Shaogui Yang,Shiyin Li,Shicheng Yan,Cheng Sun,Limin Zhang,Zhigang Zou
Identifying the spatial effects of cobalt cations in cobalt-based heterogeneous catalysts contributes to develop effective peroxymonosulfate (PMS) activators in water treatment. Herein, we investigated typical tetrahedral and octahedral cobalt ions in CoAl 2 O 4 and ZnCo 2 O 4 via an inactive cation substitution strategy towards spinel Co 3 O 4 . ZnCo 2 O 4 (0.095 min −1 ) performs remarkably better than CoAl 2 O 4 (0.007 min −1 ) for degrading rhodamine B, while non-radical 1 O 2 is the dominant reactive oxygen species. Then, interface kinetics characterized by systemic electrochemical techniques indicate the feasibility of Co 2+ /Co 3+ transformation and charge transfer resistance at catalyst-electrolyte interface determine intrinsic activity. Octahedral cobalt species exhibit superior intrinsic activities comparing with tetrahedral ones on the removal of several dye and aromatic pollutants. Additionally, flat band potentials of cobalt-based oxides reflecting Fermi level positions is a thermodynamic factor to activate PMS. Our work attempts to further understand spatial occupation-activity relationship of cobalt sites to design efficient PMS activators.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Journal of Food Measurement and Characterization
·
2024
·
IF 2.9
Feng Simin,Liang Shuqi,Sui Minghui,Yu Jiahao,Lin Yang,Gu Hong,Sun Peilong,Shao Ping
Flavonoids play a major role in promoting human health, yet their instability in solution greatly limits its industrial utilization. This study aimed to introduce soybean peptides (SP) to improve the stability and solubility of Dendrobium officinale flavonoids (DOFs), and to investigate the effects of their interaction, sterilization and storage. The results revealed that DOFs bind to SP through hydrogen bonding and steric effects, leading to changes in the structure, energy, and activity of DOFs, which resulted in enhanced stability and antioxidant capacity. The sedimentation rate and flavonoid content were measured to be 24.64 ± 0.55%, 3.83 ± 0.14 mg/mL, respectively, at the optimum mass ratio of DOFs and SP of 2:5. After thermal treatment, the flavonoid content and antioxidant activity of the complexes both dramatically enhanced. The optimum sterilization condition was 75 °C for 20 min, while the optimum range of temperatures for storage was 4 ~ 25 °C. These findings provide valuable insights for the processing, preservation and application of flavonoids in the future.
研究领域:
药学
·
食品科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Xinxue Zhang,Zhijie Huang,Wenying Liu,Xudong Yang,Lijun Yin,Xin Jia
A novel antibacterial film based on arabinoxylan (AX) was prepared by introducing ferulic acid (FA) to AX through a laccase-catalyzed procedure. The ferulic acid-arabinoxylan conjugates (FA-AX conjugates) have been characterized. Results showed that FA was successfully grafted onto the AX chains by covalent linkages, likely through nucleophilic addition between O-Ph in the phenolic hydroxyl group of FA, or through Michael addition via O-quinone intermediates. FA-AX conjugates showed improved crystallinity, thermal stability, and rheological properties, as well as a distinct surface morphology, compared with those of native AX. Moreover, FA-AX conjugates exhibited enhanced antibacterial ability against Staphylococcus aureus , Escherichia coli , Shewanella sp ., and Pseudomonas sp . Mechanistic studies revealed that the enhanced antibacterial ability was due to the penetration of bacterial membrane by the phenolic molecule and the steric effect of FA-AX conjugates. The study demonstrates that the laccase-induced grafting method was effective in producing FA-AX conjugates; we have demonstrated its antibacterial ability and great potential in prolonging the shelf life of fresh seafood products.
研究领域:
材料科学
·
食品科学
·
生物技术
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2018
·
IF 4.908
Yang Zhou,Lu Li,Lijun Jin,Jian Zhou,Zhiwei Shi,Yang Li,Haoquan Hu
Coal pyrolysis is generally considered to initiate by cleavage of weak covalent bonds bridged between aromatic rings. The C–C covalent bonds are predominant bridged linkages among the framework of coal, which have a critical influence on coal pyrolysis reaction but lack of direct online observation. Five representative coal-related model compounds containing C–C bridged bonds, polypropylene (PP), polyvinylpyrrolidone (PVP), poly-4-vinylpyridine (P4VP), polystyrene (PS) and poly-4-vinylphenol, were selected to pyrolyze in an in-situ pyrolysis vacuum ultraviolet photoionization mass spectrometry (Py-VUV-PIMS). The soft ionized mass spectral detection can provide product distribution and evolved information of original products and intermediates, which are the key evidence to understand the initiation, recombination and reaction routes during pyrolysis process. Online analysis of pyrolysis reaction was found to be priority with cracking of C–C bond in the five polymer samples, and homologous free radicals and original products, which mainly include monomers, dimers and their alkyl and alkenyl radicals, were detected. The results reveal the cleavage temperature of C–C covalent bond is deeply related to its chemical environment, and obvious conjugation effect and steric effect for the bridged linkage were observed. In addition, the effect of hydrogen bond was also observed during the pyrolysis of model compounds containing hydroxyl groups, and intramolecular or intermolecular hydrogen bonding reduced the temperature at which C–C bridged bonds break. The analogous fracture mode and pyrolysis behavior of coal-related model compounds, which are beneficial to understand the reaction route and mechanism of coal pyrolysis, were discussed based on the experimental observations and theoretical calculation.
研究领域:
化学工程
·
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 38
·23272-23278
·
IF 3.108
Peicheng Wang,Yang Zhao,Hongbin Zhang,Tao Yu,Yahong Zhang,Yi Tang
A series of diquaternary pyrazolium-derived organic templates (N,N′-dimethyl-N,N′-1,6-dihexylidenedipyrazolium, N,N′-diethyl-N,N′-1,6-dihexylidenedipyrazolium, N,N′-dipropyl-N,N′-1,6-dihexylidenedipyrazolium, denoted as 6C-DMP, 6C-DEP, 6C-DPP, respectively) with methyl, ethyl and propyl groups substituted on the N atom of pyrazole ring at both terminals have been used in the synthesis of high silica MTW and MFI zeolites. Through combining the characterization results, including XRD, NMR, elemental analysis, TG, XRF, FE-SEM, N2 sorption and FE-TEM, with molecular mechanics simulations to explore the location, orientation and the interaction energies of the three templates, we confirmed the state of templates in zeolite framework, carefully characterized their morphology/structure properties, and finally investigated their different spatial effects for the zeolite formation. The study found that 6C-DMP and 6C-DEP are able to produce MTW, while 6C-DPP is able to produce MFI. 6C-DMP, owing to a good match with the MTW framework and can be used to synthesize regular MTW zeolite with few defects. The MTW zeolite prepared by using 6C-DEP as a template presents more defects and irregular macromorphology due to a relatively poor match to the MTW framework. 6C-DPP can get MFI other than MTW due to a larger spatial hindrance, and it is located in the MFI framework with a special spatial orientation.
研究领域:
化学
·
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）