SYNTHESIS-STUTTGART
·
2023
·Vol. 55
·期 20
·3393-3401
·
IF 2.6
Yue-Lu Zhu,Jie Yan,Xiu-Xuan Xu,Zong-Yu Sun,Jiao Chen
Copper-catalyzed coupling reaction involving N-phenoxyacetamides and 2H-azirines is described, in which N–O and C–N bonds are broken and restructured. This protocol provides an efficient strategy for the highly regioselective synthesis of racemic α-amino oxime ethers. In addition, this strategy can be used to modify natural products and is gram-scale compatible.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
POLYMER INTERNATIONAL
·
2017
·Vol. 66
·期 7
·1037-1043
·
IF 2.07
Guoping Li,Haoxue Dong,Menghui Liu,Min Xia,Chunpeng Chai,Yunjun Luo
The triblock energetic copolymer poly(lactic acid)- block -(glycidylazide polymer)- block -polystyrene (PLA- b -GAP- b -PS) was synthesized successfully through atom-transfer radical polymerization (ATRP) of styrene and ring-opening polymerization of d,l -lactide. The energetic macroinitiator GAP-Br, which was made from reacting equimolar GAP with α -bromoisobutyryl bromide, firstly triggered the ATRP of styrene with its bromide group, and then the hydroxyl group on the GAP end of the resulting diblock copolymer participated in the polymerization of lactide in the presence of stannous octoate. The triblock copolymer PLA- b -GAP- b -PS had a narrow distribution of molecular weight. In the copolymer, the PS block was solvophilic in toluene and improved the stability of the structure, the PLA block was solvophobic in toluene and served as the sacrificial component for the preparation of porous materials, and GAP was the basic and energetic material. The three blocks of the copolymer were fundamentally thermodynamically immiscible, which led to the self-assembly of the block copolymer in solution. Further studies showed that the concentration and solubility of the copolymer and the polarity of the solvent affected the morphology and size of the micelles generated from the self-assembly of PLA- b -GAP- b -PS. The micelles generated in organic solvents at 10 mg mL −1 copolymer concentration were spherical but became irregular when water was used as a co-solvent. The spherical micelles self-assembled in toluene had three distinct layers, with the diameter of the micelles increasing from 60 to 250 nm as the concentration of the copolymer increased from 5 to 15 mg L −1 . © 2017 Society of Chemical Industry
研究领域:
材料科学
·
高分子化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2024
·
IF 5.8
Jinyu Dai,Tianyu Yang,Yunlan Sun,Baozhong Zhu
Aluminum powder has a high energy density, but it is easy to agglomerate during the combustion process, which can lead to a decrease in the combustion efficiency. Ammonium perchlorate (AP) and glycidyl azide polymer (GAP) are commonly used an oxidant and a binder in solid propellants. They can promote the combustion of aluminum powder to a certain extent, but their coupling mechanism is still lacking. In this study, GAP and AP were sequentially coated on the surface of nano-sized aluminum powder by a dissolution-recrystallization method, and the coupling effect of AP/GAP on the combustion of aluminum powder and the influence of the AP/GAP coating ratio on the combustion performance of aluminum-rich fuel were studied by using an ignition laser method combined with a spectrum diagnosis test. The promotion effect of AP/GAP on the combustion of aluminum powder was analyzed. The chain-like coating structure of GAP can form a steric hindrance mechanism and inhibit the agglomeration of aluminum powder. The heat of GAP decomposition at a lower temperature accelerates the decomposition of AP and makes the aluminum powder come into contact with the oxidizing atmosphere more quickly. At the same time, the heat provided by GAP combustion can quickly break the local oxide film on the surface of aluminum powder, so that the activated aluminum overflows. When the content of aluminum powder is constant, the combustion performance of the sample with AP: GAP = 3:1 is better than that of the sample with AP: GAP = 4:1. When the aluminum powder content reaches 65 wt.%, its combustion performance is the best, and the ignition delay is reduced by about 21 %. The combustion of the Al-AP/GAP system generates more nitrides . These nitrides can react with alumina and hinder the formation of alumina during the reaction, thereby suppressing combustion interruption.
研究领域:
材料科学
·
燃烧动力学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2021
·
IF 5.455
Shuoyu Wang,Xianyu Qiu,Yangguan Chen,Shuixia Chen
Amine-functionalized porous adsorbent is one kind of important materials in carbon dioxide capture due to its stability and efficiency. In this study, a copolymer (polyHIPE) with interconnected macropore networks, hierarchical porous structure and abundant branched amino groups was prepared by high internal phase emulsion (HIPE) strategy via copolymerization of styrene (St), divinylbenzene (DVB), tetraethyl orthosilicate (TEOS), and triethoxyvinylsilane (VTEO), and then a novel amine-functionalized CO 2 adsorbent was synthesized by in situ ring-opening grafting copolymerization of aziridine with the polyHIPE. The structure, morphology, and physicochemical properties of the polyHIPEs were characterized by FTIR, TEM, TGA , and SEM. The key roles of VTEO and TEOS in introducing active hydroxyl groups onto the surface of the inert polymer was evaluated, which was essential to improve the hydrophilicity of the polyHIPE and to provide reactive sites to combine with amine agents. The contact angle of the polyHIPE while copolymerized with TEOS and VTEO significantly was decreased from 144° to 72°. In order to further increase the specific surface area of the polyHIPEs, post crosslinking of polyHIPEs was implemented through a Friedel–Crafts reaction. The specific surface area of post-crosslinked polyHIPE could reach 513 m 2 /g, which was proven to be effective to enhance its CO 2 adsorption capacity. Finally, the abundant branched amino sites via aziridine grafting and high surface area greatly enhanced CO 2 adsorption capacity of the amino-modified polyHIPEs. The adsorption capacity of 2.40 and 3.25 mmol CO 2 /g could be achieved under dry and humid conditions in 0.1 atm partial pressure of CO 2 , respectively.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 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）