DESIGNED MONOMERS AND POLYMERS
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2015
·
IF 2.78
Yaobin Liu,Zhiqiang Fan
A novel radical addition-coupling polymerization method is applied to prepare gels with controlled chain structure and length between branch points. Structure of the chains was varied between rigid or flexible ones by synthesizing different tribromide and dibromide monomers and reacting them with 2-methyl-2-nitrosopropane (MNP) under catalysis of Cu/N,N,N′,N′′,N′′-pentamethyldiethylene-triamine. The carbon radical generated by single electron transfer from the bromides can be efficiently captured by MNP, forming nitroxide radical. The in situ formed nitroxide radical immediately undergoes cross-coupling reaction with another carbon radical, generating gel bridged with alkoxyaime moiety via step-growth mechanism. The tribromide and dibromide monomers were synthesized from different saturated and unsaturated compounds, or by bulk atom transfer radical polymerization of styrene using small bromide as initiator. The rigid gel has better controlled chains between branch points than the flexible ones. Selective dissociation of the ester group in the backbone of chains has been realized, which reserved the weak of NO–C. Flory–Huggins interaction parameter χ of the gels with fixed length between branch points were measured, which solved the difficulty that χ of insoluble polymer cannot be determined by common methods used for soluble polymers.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICA CHIMICA ACTA
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2017
·
IF 4.95
Yao Sun,Zhaobing Guan,Hongwei Cai,Yiyong Huang,Yawei Lin,Xiaosong Hu
A pre-column fluorescent derivatization method based on nitrone formation has been applied to determine furfurals (e.g. furfural (F), 5-methyfurfural (5-MF) and 5-hydroxymethylfurfural (5-HMF)) in food samples for the first time. An N-substituted hydroxylamine reagent 4-((hydroxyamino)butyl)-7-hydroxycoumarin (HAHC) was used to react with the aldehyde group of furfurals to form stable nitrone derivatives with high fluorescence intensities . The reactions proceeded under mild conditions in 30 min with high derivatization yields (>93%). A baseline-separation of three furfurals derivatives was subsequently achieved within 25 min on a reversed-phase column. The detection limits were at the low femtomol level (S/N = 3, 20 μL per injection). The linear range of the calibration curve was 0.4–4000 nM with good correlation coefficients (R 2 ≥ 0.9991). The proposed method was further applied for food sample analysis, such as bovine milk powder and raisin. Satisfactory recoveries were obtained in the range of 94.7%–103.5%. Above all, this pre-column derivatization method is simple, fast and highly sensitive, providing an effective and promising way for future studies of aldehydes in different matrices.
研究领域:
分析化学
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食品科学
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产品关联
DOI
PubMed
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2020
·Vol. 221
·期 17
·2000160
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IF 2.335
Junfeng Zhu,Ting Zhu,Huan Tuo,Mengmeng Yan,Wanbin Zhang,Guanghua Zhang,Xiaowu Yang
Poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (PTMA) is a typical organic battery material containing nitrogen and oxygen radicals. The grafting of PTMA onto graphene oxide to obtain composite cathode material poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate)-Graphene Oxide (PTMA-GO) via click chemistry is reported. The method of preparing PTMA-GO is completed at room temperature, which can retain the oxygen-containing functional groups on the surface of graphene oxide, and the process is simple and easy to conduct. The composite materials are characterized by infrared, X-ray diffraction, thermogravimetry, and electron paramagnetic resonance. The cathode material is assembled in a button battery to measure its cyclic voltammogram, electrochemical impedance spectroscopy, and charge and discharge capacity cycles. It is found that the PTMA-GO electrode is twice as conductive as the PTMA electrode alone. The specific capacity of the PTMA-GO electrode is nearly 2.3 times higher than that of the PTMA electrode after 300 charge–discharge cycles. This represents an important reference value for the development of organic batteries, especially for the research of nitroxide radical polymer electrode materials.
研究领域:
材料科学
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电化学
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能源存储
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2017
·Vol. 24
·期 9
·3635-3644
·
IF 3.417
Liu Shaojie,Xing Yubin,Han Jiangze,Tang Erjun
A novel amphiphilic block copolymer of poly(ethylene glycol)-b-poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl-methacrylate) was prepared through activators regenerated by electron transfer atom transfer radical polymerization of 2,2,6,6-tetramethylpiperidine methacrylate monomer, followed by oxidizing it with 3-chloroperoxybenzoic acid. This nitroxide block copolymer was used as a recoverable catalyst instead of free 2,2,6,6-tetramethylpiperidine-1-oxyl for selective catalytic oxidation of cellulose. According to its amphiphilic property, a mixture of acetonitrile and water was used as the reaction medium. The resulting carboxyl content of oxidized cellulose reached 1.07 mmol/g, equivalent to 73.2% of free TEMPO, was satisfactory. Furthermore, the block copolymer was easy to recycle and the activity did not decrease to a noticeable level after 4 cycles.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2024
·
IF 3.3
Huaiyuan Zhang,Nuo Xu,Botao Su,Jingren Zhang,Chongen Zhang,Zhiyuan Zhang,Binbin Guo,Shengjie Xu,Shouwei Wang,Rongping Tang
A metal-free, mild, and efficient method for the synthesis of amides has been developed from the amination of aldehydes with hydroxylamines promoted by TBAF·3H2O in the presence of KOH. Control experiments showed that the nitrone was the intermediate of this amination. By this method, a series of amides, biologically active compounds bebenil and a COX inhibitor were obtained in moderate to good yields.
研究领域:
有机化学
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合成化学
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药物化学
✓ 已验证
DOI
PubMed
高影响因子
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