HIGH PERFORMANCE POLYMERS
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2021
·
IF 2.161
Zijin Luo,Zhe Chen,Jun Wei,Dongchao Wang,Han Chen,Rui Chen
A novel intumescent flame retardant, PPMD, was designed from phosphaphenanthrene and nitrogen heterocycles through the two-step gut reactions of 1,4-phthalaldehyde and 3-methyl-1-phe-nylpyrazol-5-ylamine. After determination of its structure by nuclear magnetic resonance and Fourier-transform infrared analyses, PPMD was added to an epoxy resin (EP) to facilitate a curing process. Thus, EP/PPMD samples with excellent transparency and flame retardancy were acquired. For example, the EP sample satisfied the UL-94 V-0 standard and achieved a limiting oxygen index value of 30.5% because of the incorporation of 5 wt% PPMD. The cone calorimeter test of the EP/5% PPMD sample revealed that its total smoke production (TSP) and total heat release (THR) values of EP/5% PPMD was only 22.5% and 56.4% of the control group, respectively. Moreover, the average effective heat of combustion (av-EHC) value of EP/5% PPMD was reduced by 34.1%, indicating that PPMD possessed high flame-inhibition activity and smoke suppression efficiency. The flame-retardant mechanisms of PPMD were also investigated in gas phase by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and in condensed phase by XPS and IR.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
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2019
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IF 2.12
Lianqing Chen,Zhongda Wu,Yanting Du,Yufeng Huang,Shiwei Jin
In order to find a new type of fluorescent insecticides, a series of phenylpyrazole Schiff base derivatives have been synthesized by a facile one-pot solvothermal method based on the amino group of fipronil addition-elimination condensation reaction with the corresponding benzaldehyde derivatives in high yields, which were fully characterized by 1 H NMR, IR, MS and elemental analysis . Crystal structure determination indicated that 1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-5-(4-fluoro-benzylidene-amino)-4-(trifluoromethylsulfinyl)-1 H -pyrazole-3-carbonitrile ( 7 ) crystallized into zigzag chains by π···π packing interactions between phenyl rings of neighbouring molecules. The investigation for insecticidal bioactivities of these pesticides against 3rd instar larvae of Plutella xylostella exhibited better activities than that of fipronil, which can be elucidated by enhanced calcium ions' coordination abilities with C N double bonds and chloride ions , extended conjugated parent structure, steric hindrance of the stereoscopic structure and electronegativity of substituted groups. The electronic absorption, fluorescent and electrochemical properties of phenylpyrazole Schiff base derivatives have been systematically investigated for the first time, which all emitted blue-green light in both solution and solid state at room temperature . The relationships between extended conjugated moieties of parent structure, positions of substituent group and the kinds of substitutes at 4-position on the phenyl ring and photophysical properties have been discussed, which was confirmed by electrochemical analysis . The alteration of absorption and emission wavelengths can be rationalized by substitutes' electronegativity and Substituents’ Hammett constants. The fluorescent quantum yields of phenylpyrazole Schiff base insecticides were almost 4 times that of Fipronil, which laid a foundation for their natural degradation and fluorescence detection of pesticide residues . This approach proposes a unique insight to provide a great number of novel phenylpyrazole Schiff base fluorescent insecticides by a general green method.
研究领域:
农药化学
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有机化学
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生物化学
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产品关联
DOI
高影响因子
Small Methods
·
2024
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IF 10.7
Li Chen,Cuiyun Zhou,Feng Jiang,Li Zhang,Chuanlai Xu
Phenylpyrazoles are widely used pesticides in the food industry. It is highly desirable to develop efficient pre-treatment and analysis methods to extract and detect phenylpyrazoles in complex food matrices. Herein, the study reports novel squaraine-linked zwitterionic core-shell magnetic covalent organic frameworks (MCOFs), which are found to be excellent pretreatment materials for the detection of trace phenylpyrazoles in samples. By coupling MCOFs to magnetic solid-phase extraction (MSPE) with Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) analysis, the detection of phenylpyrazoles (fipronil, fipronil sulfone, fipronil sulfide, fipronil de-sulfoxide, fipronil desulfinyl, ethiprole, and flufiprole) is achieved and shows good linearity at concentrations of 1–800 µg L −1 (R 2 ≥ 0.9930). The limit of detection (LOD), limit of quantification (LOQ), and recovery rates are 0.01–0.50 µg kg −1 , 0.04-1.72 µg kg −1 , and 70.96–115.32%, respectively. More importantly, this method is successfully applied to determine the phenylpyrazoles in commercial egg, poultry, milk, jujube, cabbage, tea, and rice with a detection rate of ≈0.04%. Therefore, the developed method may contribute to a new strategy for the purification and multi-target extraction of complex food matrices.
研究领域:
分析化学
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食品安全
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材料科学
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产品关联
DOI
PubMed
高影响因子
ChemistrySelect
·
2023
·Vol. 8
·期 9
·e202203332
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IF 2.1
Cunwei Qian,Ying Wang,Xian Li,Changsheng Yao
Graphical A convenient, rapid and electrochemical one-pot protocol is designed for the synthesis of pyrazolo[3,4- b ]quinolines derivatives. The reaction is carried out in an undivided cell equipped with an iron cathode and a graphite anode in the presence of sodium bromide as a supporting electrolyte. Fourteen pyrazolo[3,4- b ]quinoline derivatives are obtained under a constant current of 30 mA after 0.14 F/mol of electricity passed. A convenient, rapid and electrochemical one-pot protocol was developed successfully for the preparation of pyrazolo[3,4- b ]-quinoline derivatives. The reaction is carried out in a 25 mL three neck flask equipped with graphite electrode as anode and iron electrode as cathode (electrode area of 1 cm 2 ) with sodium bromide as supporting electrolyte at room temperature in ethanol. Fourteen pyrazolo-[3,4- b ]-quinoline derivatives were synthesized by use of various aldehyde (including aryl aldehydes and aliphatic aldehydes), dimedone and 5-amino-3-methyl-1-phenylpyrazole as substrates in good yields (76–86 %) with a constant current of 30 mA after 0.14 F/mol of electricity passed. All aimed products were characterized by IR, 1 H NMR and HRMS. Notably, the presented method features ecologically sound, simple experimental procedure and good yields.
研究领域:
有机化学
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电化学
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DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2016
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IF 2.857
Jing-Bo Liu,Yu-Xin Li,Xiu-Lan Zhang,Xue-Wen Hua,Chang-Chun Wu,Wei Wei,Ying-Ying Wan,Dan-Dan Cheng,Li-Xia Xiong,Na Yang,Hai-Bin Song,Zheng-Ming Li
To discover potent insecticides targeting ryanodine receptors (RyRs), a series of novel anthranilic diamides analogues (12a–12u) containing N-substituted phenylpyrazole were designed and synthesized. These compounds were characterized by 1H NMR, 13C NMR, and HRMS, and the structure of compound 12u was confirmed by X-ray diffraction. Their insecticidal activities indicated that these compounds displayed moderate to excellent activities. In particular, 12i showed 100 and 37% larvicidal activities against oriental armyworm (Mythimna separata) at 0.25 and 0.05 mg L–1, equivalent to that of chlorantraniliprole (100%, 0.25 mg L–1; and 33%, 0.05 mg L–1). The activity of 12i against diamondback moth (Plutella xylostella) was 95% at 0.05 mg L–1, whereas the control was 100% at 0.05 mg L–1. The calcium-imaging technique experiment results showed that the effects of 12i on the intracellular calcium ion concentration ([Ca2+]i) in neurons were concentration-dependent. After the central neurons of Helicoverpa armigera were dyed by loading with fluo-5N and treated with 12i, the free calcium released in endoplasmic reticulum indicated the target of compound 12i is RyRs or IP3Rs. The activation of RyRs by natural ryanodine completely blocked the calcium release induced by 12i, which indicated that RyRs in the central neurons of H. armigera third-instar larvae is the possible target of compound 12i.
研究领域:
农药化学
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昆虫生理学
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药物化学
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产品关联
DOI
PubMed
高影响因子
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