Polymer Chemistry
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2024
·Vol. 15
·期 21
·2148-2156
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IF 4.1
Xiao-Yu Zhang,Hao-Liang Li,Bo Xiang,Xiang-Wei Liu,Shu Zhang,Yi-Xian Wu
A series of imidazolidin-2-iminato vanadium complexes VOCl2[1,3-R2-(CH2N)2CN], Vi1, R = 2,6-Me2C6H3; Vi2, 2,4,6-Me3C6H2; Vi3, R = 2,6-iPr2C6H3; Vi4, R = cyclohexanyl, were synthesized and fully characterized by NMR (1H, 13C and 51V) and elemental analysis. The copolymerizations of ethylene with propylene using the imidazolidin-2-iminato vanadium complexes were conducted in the presence of Et3Al2Cl3. The catalytic activity increased in the order of Vi4 < Vi1 < Vi2 < Vi3, probably due to the different electron donating natures of the imidazolidin-2-iminato ligands. Both high catalytic activity of 2.44 × 106 g copolymer per mol of V per h and incorporation ratio of propylene (up to 32.5 mol%) were afforded by using the Vi3/Et3Al2Cl3 catalytic system in the copolymerization of ethylene with propylene. An ethylene–propylene copolymer with ultra-high molecular weight (Mw = 2660 kg mol−1) could be also synthesized by using the Vi3/Et3Al2Cl3 catalytic system. Importantly, the highly efficient terpolymerizations of ethylene, propylene with 5-ethylidene-2-norbornene (ENB) were also achieved by using this catalytic system, affording ethylene–propylene–ENB terpolymers (EPDMs) with high contents of ENB units up to 9.8 mol% (29.8 wt%) and ultra-high molecular weight (Mw = 1521–2537 kg mol−1). This work offers a unique catalytic system of vanadium complexes for the synthesis of EPDM with both high content of ENB units and ultra-high molecular weight.
研究领域:
聚合物化学
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材料科学
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DOI
高影响因子
WATER RESEARCH
·
2018
·
IF 7.051
Zi-Bin Xu,Wen-Long Wang,Nan Huang,Qian-Yuan Wu,Min-Yong Lee,Hong-Ying Hu
2-Phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) is an antiscalant that is widely used in reverse osmosis (RO) systems. Because of its high concentration in RO concentrate, eutrophication risk and anti-precipitation properties may affect subsequent treatments, therefore treatment strategies are needed to eliminate such substances. In this study, PBTCA was degraded by ozonation . The results show that PBTCA reacted with ozone molecules and hydroxyl radicals , with second-order rate constants of (0.12 ± 0.002) and (7.83 ± 1.51) × 10 8 L mol −1 s −1 , respectively. The phosphorus in PBTCA (P P ) was transformed into organic phosphorus except for PBTCA (P O ), and inorganic phosphorus (P I ); P O was further transformed into P I . The changes in the concentrations of these phosphorus forms were investigated by model simulation. Simulation showed that the rate of P P transformation into P O was 5.5 times higher than that into P I . PBTCA was ozonated much faster at alkaline pH than at acidic pH. This is ascribed to different amounts of ozone molecules and hydroxyl radicals, and their different reaction rates with PBTCA. Furthermore, anti-precipitation property was reduced during ozonation , as shown by the amounts and morphology changes of the precipitates. PBTCA concentration for 50% anti-precipitation (AP 50 ) did not change during ozonation, indicating that the transformation products generated during ozonation did not have anti-precipitation effects. Phosphorus in PBTCA was removed by ozonation–coagulation treatment. Total phosphorus and inorganic phosphorus were removed efficiently by using ferric chloride as a coagulant. The coagulants tended to bind with inorganic phosphorus to form flocs. Meanwhile, flocs were more easily to aggregate and precipitate as anti-precipitation effect was gradually removed, thus more phosphorus was removed. A combination of ozonation and coagulation removed PBTCA effectively and simultaneously reduced its anti-precipitation property and phosphorus.
研究领域:
环境科学
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水处理工程
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化学动力学
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DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2024
·
IF 3.9
Jingwen Yao,Jiaying Tong,Dan Zhao,Dong Chen,Yuhong Ma,Wantai Yang
The reversible addition-fragment chain transfer (RAFT) alternating copolymerization of 2-hydroxyethyl vinyl ether (HEVE) and dimethyl maleate (DMM) is achieved with S -(cyanomethyl) O -ethyl carbonodithioate (CMX) as medaitor and 2,2′-azobis(2-methylpropionitrile) (AIBN) as radical initiator. The effects of monomer concentrations, comonomer feeding ratios, molar ratio of monomer to CMX and solvent on the copolymerization and copolymer structure are systematically investigated. The living feature of the HEVE and DMM copolymerization is demonstrated by the linear increasement of the molecular weights with the monomer conversions, and relatively narrow molecular weight distributions of the copolymers. With dimethyl carbonate as solvent, poly(HEVE- alt -DMM) with M n = 5200 and M w / M n = 1.34 are synthesized at [HEVE]/[DMM]/[CMX]/[AIBN] = 100/100/3/1. The alternating structure of the copolymer is demonstrated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and proton nuclear magnetic resonance spectroscopy ( 1 H NMR). The both α, ω-end groups are mainly originated from the moiety of CMX. To further demonstrate the living feature of the alternating copolymerization, chain extension and block copolymerization are also carried out. With poly(HEVE- alt -DMM) as macro-CTA ( M n = 5200, M w / M n = 1.34), the chain-extension reaction has been successfully realized ( M n = 9600, M w / M n = 1.70), and the block copolymer with vinyl neonanoate as monomer also successfully synthesized ( M n = 9800, M w / M n = 1.42). Graphical
研究领域:
高分子化学
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材料科学
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2013
·
IF 3.365
Danhua Yuan,Shutao Xu,Mozhi Zhang,Yingxu Wei,Xinglong Dong,Yanli He,Shuliang Xu,Zhongmin Liu,Yunpeng Xu
ZSM-2 nanorods with crystal size around 50 nm were successfully synthesized at ambient temperature (30 °C). The crystallization process of ZSM-2 zeolite under ambient temperature was studied and discussed according to the measurement of crystallization kinetic curve, and characterizations with multiple techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), low-temperature N 2 adsorption/desorption analysis, thermogravimetry analysis (TG) and nuclear magnetic resonance (NMR) etc. The ZSM-2 zeolite synthesized at ambient temperature presented different crystal morphologies and large specific area as compared with the sample synthesized at high temperature (100 °C). Furthermore, 29 Si MAS-NMR showed that the nanoscale ZSM-2 obtained by ambient synthesis contained more EMT phase and lower Si/Al ratio than that of micrometer-sized ZSM-2 crystals obtained at 100 °C. More interestingly, NMR and low-temperature N 2 adsorption/desorption characterizations revealed that the local environment of Al did not change much while that of Si did change a lot during the ambient crystallization process, and the micropore area increased rapidly while the micropore size distributions of the samples changed little with increasing crystallization time.
研究领域:
材料科学
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化学工程
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物理化学
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DOI
高影响因子
JOURNAL OF HETEROCYCLIC CHEMISTRY
·
2023
·
IF 2.4
Ping Zhao,Qingle Zeng
We have developed a diversity-oriented, substrate-controlled, chemoselective synthetic method for a variety of structurally diverse 1-sulfonylquinazoline-2,4(1H,3H)-diones and 2-sulfonamidobenzonitriles. This substrate-controlled synthesis is accomplished through the condensation reaction of 2-(sulfonamido)benzamides with or without an N-methyl group on the amides. The reactions are fulfilled within half an hour at room temperature with solid triphosgene as a convenient condensing agent and pyridine as an acid acceptor. This protocol features easily available starting materials, mild reaction conditions, easy experimental operation, and moderate to excellent yields of products.
研究领域:
有机化学
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药物化学
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DOI
高影响因子
PHYTOCHEMISTRY
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2024
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IF 3.2
Hao-Dong Yang,Yuan-Gui Yang,Zhi-Shu Tang,Kang Ma,Hong-Bo Xu
Acanthopanacis cortex (the dried root bark of Acanthopanax gracilistylus W. W. Smith) has been used for the treatment of rheumatic diseases in China for over 2000 years. Four previously undescribed lignans ( 1 – 4 ) and 12 known lignans ( 5 – 16 ) were isolated from Acanthopanacis cortex. In this study, the inhibitory activities of compounds 1 – 16 against neutrophil elastase (NE), cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) are reported. The results show that compounds 1 – 16 exhibit weak inhibitory activities against NE and COX-1. However, compounds 2 , 6 – 8 and 13 – 16 demonstrate better COX-2 inhibitory effects with IC 50 values from 0.75 to 8.17 μ Μ. These findings provide useful information for the search for natural selective COX-2 inhibitors.
研究领域:
药理学
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中药学
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天然产物化学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2019
·
IF 7.149
Wei Guo,Jian Han,Shengmin Wu,Xiongjie Shi,Qiangwei Wang,Bingsheng Zhou
Bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) is a ubiquitous environmental contaminant, but its toxicity is not fully understood. Accordingly, we investigated the effects of TBPH and its metabolite, mono-(2-ethyhexyl)tetrabromophthalate (TBMEHP), on lipid metabolism using a zebrafish model. The molecular docking study revealed that TBPH and TBMEHP bind to zebrafish peroxisome proliferator-activated receptor γ (PPARγ), with binding energies similar to rosiglitazone, a PPARγ agonist. Zebrafish embryos 0.75 hpf were exposed to TBPH (0.2–2000 nM) or TBMEHP (0.2–2000 nM) until 72 hpf, and their effects on PPARγ-mediated lipid metabolism were evaluated. Significant regional DNA demethylation of the PPARγ promoter was observed in the larvae at 72 hpf. Demethylation of the PPARγ promoter accompanied by upregulation of tet1 and tet2 transcription caused upregulation of PPARγ transcription and certain downstream genes involved in lipid lipolysis, transport, and metabolism. The triglyceride and total cholesterol concentrations in the larvae were significantly reduced following exposure to TBPH or TBMEHP. Furthermore, significant increases in the whole ATP content and locomotor activity in the 120 hpf larvae were observed. The overall results suggest that both TBPH and TBMEHP affect methylation of the PPARγ promoter, subsequently influencing larvae lipid metabolism via the PPARγ signaling pathway and disrupting energy homeostasis.
研究领域:
环境毒理学
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分子生物学
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发育生物学
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表观遗传学
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DOI
PubMed
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2025
·
IF 17.7
Pengkun Zhang,Qinhan Wu,Haoyu Wang,Dong-Hau Kuo,Yujie Lai,Dongfang Lu,Jiqing Li,Jinguo Lin,Zhanhui Yuan,Xiaoyun Chen
Herein, we established a Zn 3 (OH) 2 (V 2 O 7 )(H 2 O) 2 /V-Zn(O,S) Z-scheme heterojunction (labeled ZnVO/V-Zn(O,S) with a heterovalent V 4+ /V 5+ states and oxygen vacancies in both phases via a one-step in-situ hydrolysis method. The NaBH 4 regulated the ZnVO/V-Zn(O,S)-3 with rich Vo and suitable n (V 4+ )/ n (V 5+ ) ratio achieved an excellent photocatalytic nitrogen fixation activity of 301.7 μmol/(g·h) and apparent quantum efficiency of 1.148% at 420 nm without any sacrificial agent, which is 11 times than that of V-Zn(O,S). The Vo acts as the active site to trap and activate N 2 molecules and to trap and activate H 2 O to produce the H for N 2 molecules photocatalytic reduction. The rich Vo defects can also reduce the competitive adsorption of H 2 O and N 2 molecules on the surface active site of the catalyst. The heterovalent vanadium states act as the photogenerated electrons, quickly hopping between V 4+ and V 5+ to transfer for the photocatalytic N 2 reduction reaction. Additionally, the Z-scheme heterojunction effectively minimizes photogenerated carrier recombination. These synergistic effects collectively boost the photocatalytic nitrogen fixation activity. This study provides a practical method for designing Z-scheme heterojunctions for efficient photocatalytic N 2 fixation under mild conditions.
研究领域:
材料科学
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催化
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环境科学
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纳米技术
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES
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2024
·
IF 3.6
Chenyang Pu,Zhi Wang,Boren Zheng,Bin Zhang
1,2,4-Triazole is a common intermediate used in the synthesis of pesticides and medicine, and has a very wide range of applications. As a kind of polynitrogen heterocycles, 1,2,4-triazole will release a lot of heat during thermal decomposition. If there is no comprehensive understanding of its pyrolysis behavior, there will be a very large thermal safety risk in the process involving 1,2,4-triazole in industrial production. At the same time, the instability of the substance may be affected by the presence of impurities, and the existing research on this aspect is quite scarce. Therefore, it is very necessary to study the effect of adding other substances on the thermal decomposition of 1,2, 4-triazole. The thermal decomposition characteristics and thermal runaway behavior of 1,2, 4-triazoles were revealed by thermodynamic experiments and various kinetic theoretical methods. According to the risk matrix, the thermal runaway danger level of 1,2, 4-triazole was determined to be level Ⅲ, which was an unacceptable risk. The results show that 1,2, 4-triazole has a huge heat release and the effect of thermal runaway is serious. In this study, three substances involved in the industrial production of fluconazole and flutriafol mixed with 1,2, 4-triazole were selected to explore their influence on the thermal decomposition of 1,2, 4-triazole under non-working conditions. DSC and ARC experiments consistently showed that these three impurities could reduce the reaction heat release of 1,2, 4-triazole to varying degrees, and confirmed that these three impurities could reduce the risk of thermal runaway of 1,2, 4-triazole to varying degrees. Among them, sodium hydride has the most outstanding performance, both in terms of reducing reaction heat release and reducing adiabatic temperature rise. The results can provide reference for loss control of 1,2,4-triazole in industrial applications.
研究领域:
化学工程
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热力学
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安全科学
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DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Shihai Zhang,Rongjuan Pei,Meixia Li,Haixia Su,Hao Sun,Yaqi Ding,Minbo Su,Chunfan Huang,Xia Chen,Zhenyun Du,Can Jin,Yi Zang,Jia Li,Yechun Xu,Xinwen Chen,Bo Zhang,Kan Ding
Previous researches suggested that polysaccharides from brown algae had anti-virus activity. We hypothesized that nature polysaccharide from marine plants might have the effect on anti-SARS-CoV-2 activity. By high throughput screening to target 3CLpro enzyme using polysaccharides library, we discover a crude polysaccharide 375 from seaweed Ecklonia kurome blocked 3CLpro enzymatic activity and shows good anti-SARS-CoV-2 infection activity in cell. Further, we show that homogeneous polysaccharide 37502 from the 375 may bind to 3CLpro well and disturb spike protein binding to ACE2 receptor. The structure characterization uncovers that 37502 is alginate. These results imply that the bioactivities of 375 on SARS-CoV-2 may target multiple key molecules implicated in the virus infection and replication. The above results suggest that 375 may be a potential drug candidate against SARS-CoV-2.
研究领域:
海洋生物学
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药理学
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病毒学
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DOI
PubMed
高影响因子
NEUROREPORT
·
2025
·Vol. 36
·期 16
·988
·
IF 1.7
Zhong Zhihong,Xu Canxin,Chen Xiao,Lin Dong,Bian Liuguan
Plain Language Summary Background Intracerebral hemorrhage (ICH) induces secondary brain injury, driven in part by oxidative stress caused by hemin, a toxic hemoglobin breakdown product. Cortical astrocytes, critical for maintaining redox homeostasis, are vulnerable to hemin-induced oxidative damage, exacerbating neuronal injury. Induced pluripotent stem cell–derived neural progenitor cells (iPSC-NPCs) have shown therapeutic potential in brain injury models by promoting neural repair, but their ability to protect astrocytes against hemin toxicity remains unexplored. We hypothesized that iPSC-NPCs coculture mitigates hemin-induced oxidative stress in astrocytes by activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) antioxidant pathway. Materials and methods Astrocytes were exposed to hemin with or without iPSC-NPC coculture. We assessed cell viability, reactive oxygen species (ROS) accumulation, apoptosis, and the role of the Nrf2/HO-1 pathway using small-interfering RNA. Results iPSC-NPC coculture significantly reduced hemin-induced oxidative damage by promoting Nrf2 nuclear translocation and upregulating HO-1, thereby decreasing ROS and apoptosis. Silencing Nrf2 abolished these protective effects. Conclusion Our findings demonstrate that iPSC-NPCs protect astrocytes from hemin toxicity via the Nrf2/HO-1 pathway, suggesting a novel therapeutic strategy for ICH-induced oxidative injury. Plain Language Summary Intracerebral hemorrhage (ICH) can cause brain damage due to oxidative stress from hemin, a toxic breakdown product of hemoglobin. This study explored whether induced pluripotent stem cell-derived neural progenitor cells (iPSC-NPCs) can protect astrocytes, which are crucial for brain health, from hemin-induced damage. Researchers found that when astrocytes were cocultured with iPSC-NPCs, oxidative stress and cell death were reduced. This protective effect was linked to the activation of the Nrf2/HO-1 antioxidant pathway. Silencing Nrf2 negated the benefits, highlighting the pathway's importance. These findings suggest iPSC-NPCs could be a promising treatment for oxidative injury in ICH. Text is machine generated and may contain inaccuracies. FAQ
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PubMed
高影响因子
Journal of Coatings Technology and Research
·
2025
·
IF 2.8
Liu Jinkang,Lv Ziqi,Zhao Yunyan,Li Guicun,Zhang Zhonghua,Song Xibin,Waterhouse Geoffrey I. N.
Self-healing anticorrosion coatings are attractive for extending the service-life of metals, especially in marine environments. This work reports the novel self-healing coatings based on (2-mercaptobenzimidazole)-loaded carbon nanocages (MBI@CNCs) embedded in a polymethyl methacrylate (PMMA) matrix. The carbon nanocages (CNCs) as inhibitor carriers provide abundant channels for loading and releasing of 2-mercaptobenzimidazole (MBI). Nanocomposite coatings containing 12 wt.% MBI@CNCs deliver the optimal anticorrosion performance as well as excellent self-healing properties when applied to carbon steels. After scratching the coatings in a corrosive medium, MBI molecules are released from the coating. The corrosion inhibitor then reacts with the metal surface to form a passivation layer by coordination and electrostatic effect. The general strategy combining the one-pot synthesis of CNCs and loading with a corrosion inhibitor is conducive to large-scale production and practical application of self-healing anticorrosion coatings.
研究领域:
材料科学
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腐蚀与防护
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纳米技术
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）