JOURNAL OF CHEMICAL RESEARCH
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2013
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IF 0.596
Xiao-Chuan Jia,Jing Li,Zhi-Rui Yu,Yu-Hu Wang,Lei Zhou,Yan-Yan Yu
Deprotection of phenylhydrazones and tosylhydrazones to their parent aldehydes and ketones has been accomplished using iodobenzene as catalyst in the presence of mCPBA as the terminal oxidant at room temperature. The reaction is general, and the target products can be obtained in good to excellent yields.
研究领域:
有机化学
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合成化学
✓ 已验证
DOI
高影响因子
Marine Drugs
·
2017
·Vol. 15
·期 7
·223
·
IF 3.503
Na Li,Huanhuan Wang,Xiaosai Qu,Yu Chen
ROMP is an effective method for preparing functional polymers due to its having characteristics of “living” polymerization and rapid development of catalysts. In the present work, poly(norbornene-methylamine), a mimic of chitosan, was synthesized via ROMP reaction. The amino-protected product, 5-norbornene-2-(N-methyl)-phthalimide, was prepared by a reaction of 5-norbornene-2-methylamine with phthalic anhydride, which was then subjected to the ROMP reaction in the presence of Hoveyda-Grubbs 2nd catalyst to afford poly(norbornene-(N-methyl)-phthalimide). The target product, poly(norbornene-methylamine), was obtained by deprotection reaction of poly(norbornene-(N-methyl)-phthalimide). The products in each step were characterized by FTIR and1H-NMR, and their thermal stabilities were determined by TG analysis. The effects of molar ratio between monomer ([M]/[I]) and catalyst on the average relative molecular weight (Mn¯) and molecular weight distribution of the produced polymer products were determined by gel permeation chromatography (GPC). It was found that theMn¯of poly(norbornene-(N-methyl)-phthalimide) was controllable and exhibited a narrow polydispersity index (PDI) (~1.10). The synthesis condition of 5-norbornene-2-(N-methyl)-phthalimide was optimized by determining the yields at different reaction temperatures and reaction times. The highest yield was obtained at a reaction temperature of 130 °C and a reaction time of 20 min. Our work provides a new strategy to synthesize polymers with controllable structures and free –NH2groups via ROMP.Keywords:ROMP;poly(norbornene-methylamine);controllable;living polymerization;chitosan
研究领域:
高分子化学
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生物材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2018
·Vol. 26
·期 1
·1-6
·
IF 1.434
Liang HuaQing,Li Sihan,Liu Dong,Liu Yijun,Long YongJiang,Liang GuoDong,Zhu FangMing
Herein, we demonstrated the synthesis and characterization of a well-defined diblock copolymer consisting of isotactic poly( p -hydroxystyrene) ( i P( p -HOS)) and 1,4- trans -polybutadiene (1,4- trans -PBD), i P( p -HOS)- b -1, 4- trans -PBD, by the combination of sequential monomer addition and deprotection. Isospecific living polymerization of p - tert - butyldimethylsilyloxystyrene and living trans -1,4-polymerization of 1,3-butadiene were catalyzed by 1, 4-dithiabutandiyl-2, 2ʹ-bis(6-cumenyl-4-methylphenoxy) titanium dichloride (complex 1) activated by methylaluminoxane (MAO) at room temperature to provide highly stereospecific isotactic poly( p - tert -butyldimethylsilyloxystyrene) ( i P( p -TBDMSOS)) and 1,4- trans -polybutadiene (1,4- trans -PBD) with narrow molecular weight distribution. Furthermore, the i P( p -TBDMSOS)- b -1, 4- trans -PBD was prepared via sequential monomer addition in the presence of complex 1 and MAO. The deprotection of the i P( p -TBDMSOS) block was promoted by concentrated hydrochloric acid to produce i P( p -HOS)- b -1, 4- trans -PBD. In addition, the resultant diblock copolymer and intermediate polymers were characterized by gel permeation chromatography, nuclear magnetic resonance and differential scanning calorimeter.
研究领域:
高分子化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Ao Gao,Wei Lu,Yuntao Liang,Zhenglong He,Jinliang Li,Yong Sun,Shuanglin Song,Xinfeng Cui,Xiang Gao
In this study, pH responsiveness of 1, 1, 1, 3, 3, 3-hexamethyldisilazane terminated m-Cresol (HTMC) in different-rank coals was investigated, and its inhibition performance regarding the spontaneous combustion of coal was explored. First, color changes in the deprotection reaction of HTMC under different acidic conditions were analyzed. Then, surface microstructures of these coals and pH values of their filtrates were tested. Subsequently, experiments were performed on different coal samples for grasping their low-temperature oxidation characteristics, weight loss rates, pore characteristics, and free radical variations. The experimental results show that HTMC can effectively protect phenolic hydroxyl groups in inhibitors, and the acidity of coal can promote the conversion rate of its deprotection reaction. For instance, in XAM coal (pH ≈ 6), sufficient H + stimulates HTMC to release massive m-Cresol which contains highly reactive phenolic hydroxyl, thereby effectively suppressing increases of the concentration and type of free radicals. The crossing point temperature (177.2 °C) and inhibition rate at 110 °C (75.9 %) of the HTMC-inhibited XAM sample are 33.1 °C and 17.9 % higher than those of the m-Cresol-inhibited one, respectively. This study confirms the applicability of pH-responsive HTMC to different-rank coals and may lay a theoretical foundation for the design of efficient reactive inhibitors.
研究领域:
化学工程
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煤科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
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