TETRAHEDRON
·
2015
·
IF 2.641
Bo Liu,Ning Zhu,Hailong Hong,Limin Han
A novel methodology for the preparation of benzothiazole derivatives via the reaction of ortho -anilino disulfides with aryl and heteroaryl aldehydes catalyzed by Na 2 S·9H 2 O has been developed. The reaction mechanism was investigated by LC–MS and 1 H NMR. The disulfide was cleaved firstly by the interchange reaction of the disulfide and metal sulfide , and the resulting thiol reacted in situ with the aldehyde to form the corresponding benzothiazoline. Subsequently, the intermediate benzothiazoline reduced the disulfide to thiol and it was oxidized to benzothiazole. The excess benzothiazoline was oxidized by air and both halves of the disulfide were ultimately converted to the desired benzothiazole.
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2019
·
IF 3.021
Qiang Zhang,Mieko Kumasaki,Xiongmin Liu,Fan Ren,Yosuke Nishiwaki,Bo Wang,Satoshi Matsue
In this work, we investigated the thermal oxidation of methyl tert-butyl ether (MTBE) using a customer-designed mini-closed-pressure vessel test and quantitatively analyzed the hydroperoxides produced in the primary oxidation via iodimetry. Results showed that MTBE formed high levels of hydroperoxide (5053 ppm) in its autoxidation at 140 °C. While the temperature was lower than 110 °C, a known condition at which hydroperoxide was undetectable, MTBE maintained stability. One of the hydroperoxides isolated from MTBE oxidation products was identified as 1-tert-butoxymethyl hydroperoxide (TBMHP) according to liquid chromatography–mass spectrometry, 1H and 13C nuclear magnetic resonance spectroscopy, and Fourier transform infrared spectroscopy analysis. The thermal decomposition of TBMHP was assessed via differential scanning calorimeter (DSC). Results indicated that exothermic onset temperature (Tonset) and thermal decomposition heat (QDSC) of TBMHP were 108.10 °C and 1478.05 J·g–1, respectively. The activation energy of TBMHP with the Kissinger method was 76.23 kJ·mol–1. Moreover, DSC experiments were employed to study the primary oxidation of MTBE with different equivalence ratios, indicating that primary oxidation temperature (T0) of MTBE was 208.52 °C with the equivalence ratio of 0.05. Increasing the equivalence ratio led to a considerable decrease in T0.
研究领域:
化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2021
·
IF 7.46
Daliang Yu,Yingying Zha,Zheng Zhong,Yiming Ruan,Ziwei Li,Lili Sun,Sen Hou
Dichlorodihydrofluorescein diacetate (DCFH-DA) has been widely used in detection of reactive oxygen species (ROS). Unfortunately, the detection process is easily affected by light irradiation during measurement, which cannot be overlooked especially for samples with a small amount of ROS. In the study, we revealed several factors that influence the ROS detection process and developed a new ROS detection method by DCFH-DA with higher stability and sensitivity. After light irradiation, the fluorescence signal of DCFH-DA solution increased significantly with pH value higher than 7.4. The increase of fluorescence signal was attributed to a self-oxidization process of DCFH-DA, which transferred dichlorodihydrofluorescein (DCFH) to 2′,7′-dichlorofluorescein (DCF) with the presence of DCF. At the beginning stage of light irradiation, i.e., when the amount of DCF was negligible compared to DCFH (DCFH-DA), the ratio of fluorescence density between samples keeps unchanged after light irradiation. On this basis, we developed a stable and sensitive ROS detection method via light irradiation. The method was successfully applied to detect ROS in HeLa cells which was induced by hydrogen peroxide (H 2 O 2 ) and plastic nanoparticles. A new insight into the proportional increase of fluorescence signal by light irradiation was revealed.
研究领域:
生物化学
·
细胞生物学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Xiong Yu,Hao Li,Min Li,Xiaoyan Wen,Shuo Deng,Sisi Liu,Ming-Yu Li,Haifei Lu
MXenes with numerous superior properties have great potential for portable and conformal humidity sensing, which can meet the ever-increasing requirements for noncontact medical diagnosis, noninvasive epidermal detection, and environmental monitoring. Due to the ambiguous mechanism, the absence of an efficient approach for improving the sensitivity and selectivity remains a big obstacle for realization of MXene-based humidity sensing. In this work, the evolution of humidity sensing mechanisms of few-layered Nb2CTx nanosheets before and after self-oxidation in aqueous solutions are clarified depending on a systematic comparison. The evolution of structure and chemical bonds in few-layered Nb2CTx nanosheets after different incubation durations has been investigated to understand the in situ self-oxidation process and establish the relationship between the oxidation degree and humidity sensing performance. Meanwhile, the humidity sensing mechanism of sensors for different few-layered Nb2CTx nanosheets has been also clarified, and the humidity sensitivity has been optimized to −2.3 × 104 with a relative humidity of 53%. Compared with the sensor prepared from as-prepared few-layered Nb2CTx nanosheets, the humidity sensing selectivity from oxidized few-layered Nb2CTx nanosheets has been improved, contributed to by the transformation of the sensing mechanism from electronic conduction to ionic conduction. Finally, the oxidized few-layered Nb2CTx nanosheets have been prepared on a PI substrate to demonstrate its application in a flexible humidity sensor, providing a facile solution for ultrasensitive wearable gas sensing.
研究领域:
材料科学
·
传感技术
✓ 已验证
DOI
高影响因子
Journal of Coatings Technology and Research
·
2024
·
IF 2.3
Lin Zecheng,Zeng Qingyuan,Zhang Yucheng,Ding Yongbo,Chen Shuai,Qiao Yongluo,Shen Liang
In order to increase the concentrations of bio-based alkyd polyols (or fatty acids) in self-crosslinking polyurethane dispersions, herein, a series of novel alkyd polyol-based autoxidizable waterborne polyurethane dispersions (AWPUDs) with different fatty acid contents, long storage stability, and low viscosity were successfully prepared by adding dimethylol propionic acid (DMPA) self-emulsifier in the late stage of their synthesis. They and their corresponding curing films were characterized by Fourier transform infrared spectroscopy (FTIR), particle size analysis, rheology measurement, storage stability evaluation, thermogravimetric analysis, dynamic thermomechanical analysis (DMA), etc. The results showed that the addition process of DMPA played a critical role for the excellent features of AWPUDs. Additionally, the crosslinking density, gel contents, and water contact angles of AWPUD films increased with the enlarged fatty acid contents, whereas their water uptake capability decreased. Moreover, a series of AWPUD coatings were prepared, and their properties like drying times, hardness development, pencil hardness, adhesion capability, impact resistance, flexibility, and water resistances were all effectively improved with the increased fatty acid contents, significantly superior to those of waterborne alkyd coatings and waterborne polyurethane coatings without fatty acids.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2020
·
IF 5.578
Tinghao Jia,Lun Pan,Si Gong,Jiawei Xie,Xiaoyu Wang,Yunming Fang,Ji-Jun Zou,Xiangwen Zhang
Highly thermal-stable jet fuel plays an important role in the advanced supersonic aircrafts, but its oxidation to the insoluble deposits is a serious problem when serving as a coolant. However, there are few reports as to the deep insights of insoluble deposits formation. Here we apply the PetroOxy device to investigate the thermal oxidation and deposition behaviors of highly thermal-stable jet fuel, using decalin as the model jet fuel, in order to explore the formation mechanism of insoluble deposits. All oxidation products (gas, liquid and solid) of fuel at different oxidation stages were separated and carefully characterized. The initial oxidation of fuel produces hydroperoxides, which then decompose rapidly to produce gas products (H 2 , CO or CO 2 ) as well as large amounts of polar species (soluble oxidized products, e.g. , alcohols, ketones, and molecular growth products). Meanwhile, these polar monomer species condense to produce soluble macromolecular oxidatively reactive species (SMORS) and insoluble deposits. The SMORS amount increases during the overall oxidation process, but the amount of insoluble deposits increases only in the presence of oxygen. The characterizations of liquid chromatography/electrospray ionization mass spectrometry and solution-state 2D heteronuclear single quantum coherence NMR confirm that the concentration of highly polar macromolecular species in insoluble deposits is much higher than that in SMORS, which causes the precipitation of the insoluble deposits from the bulk fuel. We further propose the detailed formation process and chemical structures of the insoluble deposits during the autoxidation of highly thermal-stable jet fuel, which would be helpful for a better understanding of the deposition mechanism of jet fuel and the improvement of its thermal stability.
研究领域:
化学工程
·
航空燃料科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Feng Feng,Chunxiao Jin,Saisai Wang,Yuxue Yue,Da Xu,Kaixuan Zhuge,Pan Gao,Jia Zhao,Renqin Chang,Lingling Guo,Huaqing Dong
There is great potential for carbon-supported gold catalysts to replace toxic mercuric chloride-based catalysts in the acetylene hydrochlorination, which is a key process for producing PVC . However, the catalyst design is essentially hindered by the difficulties in enhancing the catalytic activity of cationic gold and suppressing the deactivation of active species. We report a strategy for self-oxidation of Au 3+ by the Au-SILP system with the [Bmim][Cl 3 ] ILs. This strategy can stabilize all gold species in the state of highly oxidized Au 3+ instead of coexisting in the Au 3+ /Au + site, which makes the catalyst exhibit excellent catalytic activity. High coordination numbers Au-Cl entities reduce the electron transfer between Au 3+ and C 2 H 2 and weaken the adsorption of C 2 H 2 on the Au active sites. Furthermore, [Bmim][Cl 3 ] ILs can self-oxidize gold nanoparticles on the support surface into Au 3+ . This study provides a new method for improving the stability and activity of gold-based acetylene hydrochlorination catalysts.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
·
2025
·
IF 0.9
Baojuan Zhao,Yiman Lan,Xiaodan Wang,Yan Ma,Ronghu Li,Weizhong Cao,Xiang Wang
Most of the previous artificial oxygen carriers realized the oxygen-carrying function through a reversible combination of penta-coordinated iron(II) porphyrin with oxygen. The other oxygen transport model, in which oxygen competes with other ligands for binding with central ions, has been rarely studied. In this study, oxygen-carrying properties of a series of hexa-coordinated complexes were investigated, with heme dimethyl ester working as an oxygen-carrying component. In addition, both oxygen uptake and the auto-oxidation rate of the hexa-coordinated complexes were also explored. The results indicate that the hexa-coordinated complexes can effectively carry oxygen, provided that there is at least one strong ligand on the fifth or sixth coordination site of the heme dimethyl ester. Promisingly, when one ligand is strong and the other ligand is weak, the hexa-coordinated complexes can exhibit highly efficient oxygen-carrying capacity. By fixing weak ligands and changing strong ligands, it was found that the coordination ability of strong ligands has a significant impact on the oxygenation curve of the system. Furthermore, the auto-oxidation rate of the hexa-coordinated complexes of heme dimethyl ester is related to the hydrophobicity of the fifth and sixth ligands. The longer the hydrophobic chain of the ligand, the slower the auto-oxidation rate. Consequently, the oxygen-binding mode of this heme derivative has the potential to be an effective oxygen carrier.
研究领域:
生物化学
·
医学化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2018
·
IF 4.908
Bo Wang,Xiong-Min Liu,Xia-Na Fu,Yuan-Lin Li,Pin-Xian Huang,Qiang Zhang,Wei-Guang Li,Li Ma,Fang Lai,Peng-Fei Wang
In this work, thermal oxidation reaction of dimethoxymethane (DMM) at low temperature was investigated with a custom-designed mini closed pressure vessel test (MCPVT) employed. The initial auto-oxidation, thermal decomposition and deep radical oxidation processes were revealed by analyzing the behavior of oxidation temperature (T) and pressure (P) in the process of MCPVT monitoring. Peroxides generated from DMM auto-oxidation were measured by iodimetry and thin-layer chromatography (TLC). The dominant peroxide was separated from oxidation products via column chromatography, with structure characterized by mass spectrometry (MS), 1 H and 13 C nuclear magnetic resonance (NMR). The thermal decomposition characteristics were determined by differential scanning calorimeter (DSC). Results show that the oxidation was mainly initiated by hydrogen abstraction on the methylenedioxy (O-CH 2 -O) of DMM when temperature was above about 310 K. The primary product of hydroperoxide, hydroperoxy(methoxymethoxy)methane was found in DMM oxidation for the first time, with a high level. Its exothermic onset temperature (T 0 ) and decomposition heat (Q DSC ) are 372.87 K and 2431.37 J·g −1 , respectively. The thermal decomposition could lead to thermal runaway of oxidation, and further transform into an explosion. In most cases, the release of radical pool after peroxides decomposition would induce a rapidly radical oxidation of DMM through an endothermic reaction at about 410 K.
研究领域:
化学工程
·
安全科学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Wenjing Wu,Xiaodan Zhao,Guohua Jing,Zuoming Zhou
Sulfite has been recently emerging as an appealing sulfate radical (SO 4 •− ) precursor for efficient treatment of organic contaminants . Due to the negligible autoxidation of sulfite, activators are often introduced to accelerate sulfite autoxidation and the concomitant generation of SO 4 •− . Present heterogeneous activators are mostly not very effective under mild conditions (pH 7.0–8.0). In this work, efficient activation of sulfite with copper oxides including Cu 2 O and CuO for iohexol degradation under mild pH conditions is proposed. In a comparison of iohexol degradation efficiency by sulfite autoxidation activated with different metal oxides (Co 3 O 4 , CoO, α-Fe 2 O 3 , γ-Fe 2 O 3 , CuO and Cu 2 O), CuO and Cu 2 O with lower toxicity are efficient activators and removal efficiencies of ~95% can be obtained at pH 8.0. SO 4 •− is identified to be the major species contributing to the removal of iohexol by electron paramagnetic resonance (EPR) spectroscopy and quenching experiment. Based on the effect of ionic strength and copper leaching , sulfite is proposed to interact with copper oxides via inner-sphere coordination. Effect of critical influencing parameters and efficacy of copper oxides in real water matrixes are investigated. The results suggest that using copper oxides as activators is a new alternative to promote sulfite autoxidation process for rapid contaminants degradation.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nano Energy
·
2017
·
IF 12.343
Jun Jiang,Shu Lu,Wei-Kang Wang,Gui-Xiang Huang,Bao-Cheng Huang,Feng Zhang,Ying-Jie Zhang,Han-Qing Yu
Iron-nickel-based electrocatalysts are a group of noble-metal-free and high-performance candidate for oxygen evolution reaction (OER), and autoxidation always occurs in their OER process. Autoxidation is a double-edged sword: it could in-situ generate high-catalytic activity sites to accelerate OER, but it also results in the attenuation of conductivity and the dissolution of active components. In this work, we propose a new strategy to relieve the negative impacts of autoxidation on OER through designing three-dimensional (3D) iron-nickel sulfide nanosheets/reduced graphene oxide (FeNiS 2 NS/rGO) nanohybrids via a one-pot colloidal method , which enabled the well dispersion and strong coupling of FeNiS 2 NS on the rGO. Such an interconnected 3D architecture could facilitate excellent electron transport , provide large amounts of active sites and prevent the dissolution of active components. The FeNiS 2 NS/rGO delivered extremely low overpotentials of 270 mV and 200 mV to reach a current density of 10 mA cm −2 , and rapid kinetics with Tafe slope of 38 mV dec −1 and 40 mV dec −1 for OER in 0.1 and 1.0 M KOH, respectively. Moreover, they could retain a great stability without activity loss over long-term continuous electrolysis and long-ageing time under air conditions. This work provides an efficient approach to resolve the autoxidation problem of FeNiS 2 NS in the OER process and develops a promising earth-abundant OER electrocatalyst towards practical applications.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Ruilin Wang,Hao Luo,Mengdi Sun,Chengyu Duan,Quan Zhou,Yinglong Lu,Zheshun Ou,Huimin Liu,Guanghui Luo,Zhuofeng Hu
The 2e − water oxidation process is an eco-friendly way to produce H 2 O 2 using water as the raw material. It avoids the low solubility of oxygen in water, unlike traditional oxygen reduction methods. However, electrocatalysts always suffer from self-oxidation during the oxidation reaction, leading to decreased activity. We solved this by using non-metal graphite electrocatalysts that undergo an evolution process to oxidized carboxylated graphite, which is even more active. A defect forms on the graphite surface that facilitates HCO 3 − adsorption. The –COOH group easily forms a –COOOH intermediate, which is advantageous for hydrogen peroxide generation. The hydrogen peroxide generation rate is 4.55 times higher than that of initial graphite. Graphite is an environmentally friendly catalyst that avoids the release of metal ions, making it more suitable for large-scale applications.
研究领域:
材料科学
·
电化学
·
环境科学
✓ 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）