JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2012
·Vol. 51
·期 3
·708-715
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IF 3.919
Yong Shen,Yinan Ma,Zhibo Li
We report a highly efficient approach to prepare dendrimers by taking advantage of the orthogonal characteristic of aza-Michael addition and thiol-yne reactions. A fifth generation dendrimer was synthesized within five steps without protection/activation procedures. The reactions proceed under benign conditions without byproducts, and the target products can be easily purified via extraction or precipitation without chromatography. The structure of each generation dendrimer was characterized using NMR spectroscopy, size exclusion chromatography, and mass spectrometry. The obtained dendrimers can have peripheral amine or alkyne groups. We demonstrated that these groups can be used for selective and specific conjugation with various functional groups. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
研究领域:
材料科学
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有机化学
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2022
·Vol. 139
·期 32
·e52747
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IF 3.057
Hao Fu,Shu-ling Gong
Waterborne polyester is a common eco-friendly material in which ester bonds are easy to hydrolyze. Therefore, we synthesized a series of waterborne comb-like polyesters (WCPEs) with hydrophilic side chains through aza-Michael addition under green and mild conditions. The physicochemical structure of the polyesters was verified by 1 H NMR, FTIR, and GPC characterizations. The pH value of dispersions dropped by less than 0.7 after storage for 2 months. The dispersions remained stable after 6 months at room temperature. In addition, the WCPEs exhibited good wetting and dispersing ability for pigment particles as Tego 740 W, which is a mature pigment dispersant product for waterborne coatings. Moreover, the cross-linked WCPEs exhibited excellent chemical resistance, there was only 1.2% weight loss, and almost no mechanism properties decline for cross-linked transparent films even after treatment under an alkaline environment for 20 days. Thus, the synthesized WCPE has potential application as an alkali resistance eco-friendly material, and possesses excellent performance as pigment-dispersion resin.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF CHEMICAL RESEARCH
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2012
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IF 0.633
Shuguang Zhou,Mingxia Xu,Siyu Ye,Dashuai Li,Jing Xu,Pei Mao,Jing Xiong
24 Aza-Michael adducts were synthesised in moderate to excellent yields by the addition of 5-substituted uracils to acrylates with ethylamine as a catalyst. Many of the adducts were obtained in almost quantitive yield without column chromatography. The procedure provideded an efficient approach to the synthesis of N-1 uracil adducts using acrylates as acceptors. The structures of the compounds were determined by 1H NMR, 13C NMR, mass spectra and X-ray crystallography analyses. The uracil unit is present in DNA and related natural products and has a broad spectrum of biological activity.
研究领域:
有机化学
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药物化学
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生物化学
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DOI
高影响因子
Catalysts
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2022
·Vol. 12
·期 12
·1658
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IF 4.501
Rong-Kuan Jiang,Yue Pan,Li-Hua Du,Ling-Yan Zheng,Zhi-Kai Sheng,Shi-Yi Zhang,Hang Lin,Ao-Ying Zhang,Han-Jia Xie,Zhi-Kai Yang,Xi-Ping Luo
Benzimidazole scaffolds became an attractive subject due to their broad spectrum of pharmacological activities. In this work, a methodology was developed for the synthesis of N-substituted benzimidazole derivatives from benzimidazoles and α, β-unsaturated compounds (acrylonitriles, acrylate esters, phenyl vinyl sulfone) catalyzed by lipase TL IM fromThermomyces lanuginosusin continuous-flow microreactors. Investigations were conducted on reaction parameters such as solvent, substrate ratio, reaction temperature, reactant donor/acceptor structures, and reaction time. The transformation is promoted by inexpensive and readily available lipase in methanol at 45 °C for 35 min. A wide range of β-amino sulfone, β-amino nitrile, and β-amino carbonyl compounds were efficiently and selectively synthesized in high yields (76–97%). All in all, a microfluidic biocatalysis system was applied to the synthesis of N-substituted benzimidazole derivatives, and could serve as a promising fast synthesis strategy for further research to develop novel and highly potent active drugs.Keywords:enzymatic synthesis;benzimidazole derivatives;continuous-flow reaction technology;continuous-flow microreactor;aza-Michael addition
研究领域:
有机化学
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生物催化
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药物化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Chen Liang,Jingjing Cui,Yongding Sun,Zhe Lu,Fukang Liu,Shiwei Feng,Guang Hu,Jin Cui,Biao Zhang
Digital light processing (DLP)-based 3D printing of hydrogels with sophisticated structures has been widely used in myriads of fields. However, the inherent covalently crosslinked network of hydrogels limits their further applications, such as working as sacrificial molds. In this work, a photocurable hydrogel system with labile covalent bonds suitable for DLP based printing to fabricate 3D complex hydrogel structures with fast- and controlled degradation ability is reported. The hydrogel precursor is composed of polyethylene glycol 400 (PEG400), a water soluble photoinitiator, and PEGDA575-Do, a degradable photocurable diacrylate monomer that can be degraded in aqueous condition via reversable aza-Michael addition reaction. The mechanical properties of formed hydrogels can be regulated by changing the PEG content and water content, and the degradation rate can be regulated by changing parameters such as PEG400 content, water content and the treating temperature. Moreover, the DLP printed degradable hydrogels networks can be used as sacrificial molds to fabricate structures from materials that cannot be directly used for DLP 3D printing (e.g. thermoplastic polycaprolactone (PCL), epoxy-based resin, and chocolate). As proofs-of-concept, a microfluidic chip is fabricated by using the biocompatible 3D printed hydrogel as a sacrificial template. Similarly, a flexible RFID tag and a flexible self-powered device are also prepared, demonstrating the potential applications in the field of flexible electronics.
研究领域:
材料科学
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生物医学工程
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柔性电子学
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高影响因子
NORDIC PULP & PAPER RESEARCH JOURNAL
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2022
·Vol. 37
·期 4
·636-648
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IF 1.595
Yunfei Liao,Huiming Fan,Yongli Zhang,Hongyan Mou,Fengyu Li,Ziyin Zhou,Jianan Liu
PAAs can be further functionalized (hydroxylation and alkoxylation) by side chain substitution. In this study, we synthesized a SiPAAOH containing hydroxyl and siloxane groups based on the Aza-Michael addition reaction and applied it for reinforcement of aged paper. The results showed that the optimum conditions of SiPAAOH synthesis were as follows: the monomer molar ratio of APTES to EtA was 0.7:0.3, the solvent system for SiPAAOH reinforced aged paper was ethanol/water = 1:5 (v/v). The alkaline SiPAAOH could increase the pH of paper to 7.68, and to improve the amount of alkaline reserve to 200 mmol/kg. The whiteness and color difference of the treated paper were not significantly different from those of the untreated paper, and the mechanical properties of the paper were obviously improved. The results of contact angle and thermogravimetry showed that the SiPAAOH-treated paper was hydrophobicity and high temperature resistance.
研究领域:
材料科学
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纸张保护
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化学工程
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DOI
高影响因子
MACROMOLECULAR RESEARCH
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2021
·Vol. 29
·期 7
·462-469
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IF 2.227
Wang Lei,Yan Shijing,Zhang Lei,Mai Yuliang,Li Weihao,Pang Hao
The degradation and recycling of waste epoxy resin products is an urgent environmental problem. To solve this issue, we use acid-/base-degradable 1,1′,1″-(1,3,5-hexahydro-s-triazine-1,3,5-triyl) tris(3-ethylamino-propan-1-one) (TAHT-EA) as curing agent to introduce the hexahydro-s-triazine (HT) ring structure into the cross-linking network to prepare degradable epoxy resin. Specifically, 1,3,5-triacryloylhexahydro-1,3,5-triazine (TAHT) and ethylamine quickly complete the Aza-Michael addition reaction at the interface of chloroform and water droplets under the catalysis of water. The FTIR spectra, NMR spectrum and mass spectrum show that mono- and bis-addition products of ethylamine coexist in the product in which the content of the primary addition product reaches 97%. TAHT-EA can be decomposed by acid and base solutions. Through NMR analysis of the degradation products, it can be explained that the degradation mechanisms are different. The breaking of amide bonds and HT rings in acid solution and the cracking of amide bonds in base solution are speculated to be the main mechanisms under these two different circumstances, respectively. We tested the mechanical, thermal and degradation properties of the epoxy resin cured by TAHT-EA, and compared it with the epoxy resin cured by 4,4′-diaminodiphenylmethane and triethylenetetramine. TAHT-EA-cured epoxy resin shows comparable mechanical properties with Young’s modulus up to 2.05 GPa and tensile strength up to 70.9 MPa. What is more, it degrades completely by 1 M H + /OH − solution at 60 °C within 36 h. Nevertheless, it exhibited a relatively low crosslinked density (633 mol/m 3 ) and low heat resistance (the initial decomposition temperature is lower than 205 °C). Overall, TAHT-EA cured epoxy resin has the potential to gradually replace traditional thermosetting resin, thereby solving the environmental problems caused by discarded epoxy resin products.
研究领域:
材料科学
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高分子化学
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环境科学
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可持续材料
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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）