JOURNAL OF APPLIED POLYMER SCIENCE
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2020
·Vol. 138
·期 7
·49831
·
IF 2.52
Tao Li,Weilin Wang,Songmeng Wang,Lingyan Liu,Weixing Chang,Jing Li
An amphiphilic block copolymer PNIPAM 53 - b -(PS 30 - co -P4AMS 10 ) was facilely prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. The immobilization of ( S )-α,α-diphenylprolinol trimethylsilyl ether onto the block copolymers was then performed through using copper-catalyzed alkyne-azide cycloaddition (CuAAC), and the generating amphiphilic diblock copolymer supported chiral catalyst PNIPAM 53 - b -(PS 30 - co -P4AMS 10 )/proTMS was self-assembled into micelles with regular diameters about 50 nm in aqueous solution. The micellar catalyst was further used for the asymmetric Michael reaction between propanal and trans -β-nitrostyrene in water. Using only 1 mol% micellar catalyst, the corresponding Michael addition products could be obtained in good yields and high enantioselectivities as well as good diastereoselectivities. In addition, this micellar catalyst could be reused at least for four times. Moreover, the micellar catalyst could be applied for the asymmetric addition reaction of 4-chlorocinnamyl aldehyde and nitromethane, and thus constructing the baclofen pharmaceutical intermediate.
研究领域:
高分子化学
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有机合成
·
催化化学
✓ 已验证
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 7
·1142
·
IF 3.164
Jianye Ji,Xin Ge,Xiaoyan Pang,Ruoling Liu,Shuyi Wen,Jiaqi Sun,Weijie Liang,Jianfang Ge,Xunjun Chen
Methoxyl-capped MQ silicone resin (MMQ) was first synthesized by the hydrosilylation of vinyl-containing MQ silicone resin and trimethoxysilane and then used in condensed room-temperature vulcanized (RTV) silicone rubber as a self-reinforced cross-linker. Results show that modified silicone rubber exhibits good light transmission. Compared with unmodified silicone rubber, the hardness, tensile strength and elongation of MMQ at the break are increased by 26.4 A, 2.68 MPa and 65.1%, respectively. In addition, the characteristic temperature of 10% mass loss is delayed from 353.5 °C to 477.1 °C, the temperature at maximum degradation rate is also delayed from 408.9 °C to 528.4 °C and the residual mass left at 800 °C is increased from 1.2% to 27.7%. These improved properties are assigned to the synergistic effect of the rigid structure of MMQ, the formation of a dense cross-linking structure in polymers and the uniform distribution of MMQ cross-linking agent in RTV silicone rubber.Keywords:cross-linker;MQ silicone resin;hydrosilylation;silicone rubber;modified
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Coatings
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2019
·Vol. 9
·期 10
·605
·
IF 2.33
Jianye Ji,Xin Ge,Weijie Liang,Xiaoyan Pang,Ruoling Liu,Shuyi Wen,Jiaqi Sun,Xunjun Chen,Jianfang Ge
To overcome the inherent limitation that the preparation of high molecular weight MQ copolymers (Mw ≥ 30,000 g/mol) via the hydrolysis and condensation of solicate salts generally results in an intractable gel, vinylphenyl-containing MQ silicone resin with a high molecular weight was designed and synthesized through the hydrosilylation reaction of vinyl-containing MQ silicone resin and linear poly(diphenylsiloxane) with two terminal Si–H bonds. The weight average molecular weight of these modified copolymers reported here is at least 30,000 dal·mol−1. These polymers have favorable thermal stability and a higher refractive index than that of the base resin due to the formation of novel regular macromolecular structures and the introduction of phenyl groups. These inorganic/organic hybrid materials could be used as a potential component for temperature-resistance electronics adhesive, heat-resistant coatings and high-performance liquid silicone rubber. Moreover, the proposed process also provides a possibility to choose higher molecular weight MQ silicones according to application requirements.Keywords:MQ silicone resin;modified;hydrosilylation;high molecular weight
研究领域:
材料科学
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有机化学
✓ 已验证
产品关联
DOI
高影响因子
SYNTHESIS-STUTTGART
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2020
·Vol. 53
·期 07
·1341-1348
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IF 2.675
Xinxin Zhao,Lin Guo,Chao Yang,Wujiong Xia
A highly regioselective [3+2] cyclization of alkenes with 2-iodoanilines under the irradiation of UV light is described. This general, metal-free strategy facilitates the direct preparation of 2-mono-/disubstituted indolines as well as spiroindolines through alkene carboamination in one step. Mechanistic studies suggested that the photochemical protocol proceeded via a radical pathway.
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
Polymers
·
2018
·Vol. 10
·期 10
·1060
·
IF 2.935
Miao-Miao Xun,Zheng Huang,Ya-Ping Xiao,Yan-Hong Liu,Ji Zhang,Ju-Hui Zhang,Xiao-Qi Yu
Rapid enzymatic degradation and fragmentation during DNA administration can result in limited gene expression, and consequently, poor efficacy. It is necessary to use novel vectors for DNA delivery. Herein, we aimed to design useful carriers for enhancing transfection efficiency (TE). These lipopolymers were prepared through Michael addition reactions from low-molecular-weight (LMW) polyethyleneimine (PEI) and linkers with three kinds of steroids. Agarose gel electrophoresis assay results displayed that the three lipopolymers could condense plasmid DNA well, and the formed polyplexes had appropriate sizes around 200–300 nm, and zeta potentials of about +25–40 mV. The results of in vitro experiments using HeLa, HEK293, and MCF-7 cells showed that these lipopolymers present higher TE than 25-kDa PEI, both in the absence and presence of 10% serum. Flow cytometry and confocal microscopy studies also demonstrated that these lipopolymer/DNA complexes present higher cellular uptake and intracellular distribution. The measurement of critical micelle concentration (CMC) revealed that these lipopolymers could form micelles, which are suited for drug delivery. All results suggest that the three materials may serve as hopeful candidates for gene and drug delivery in future in vivo applications.Keywords:gene vectors;Michael addition;lipopolymers;steroids
研究领域:
生物化学
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分子生物学
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药学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Coatings Technology and Research
·
2022
·Vol. 19
·期 6
·1731-1741
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IF 2.339
He Jiajian,Cheng Kai,Lin Ruijun,Su Qiuping,Li Yong,Ma Zhiping,Wang Shaoshun,Gu Yuxin,Lin Xiaofeng,Lin Wenjing,Yi Guobin
In this work, a malonate polyester suitable for Michael addition reaction was prepared by melting polycondensation of neopentyl glycol, terephthalic acid, and diethyl malonate, and its structure was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). Then, Michael addition reaction between malonate polyester and diphenylmethane bismaleimide (BDM), catalyzed by 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU)/benzoic acid salt, was carried out to prepare the films with different contents of curing agent. The thermal and mechanical properties of the films were characterized by dynamic thermomechanical analysis, thermogravimetric analysis, and differential scanning calorimetry. We found that glass transition temperature ( T g ) of the films increased with the increase in BDM amount. The T g could reach up to 80°C, which indicated that the fabricated films show excellent thermal stability.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
·
IF 19.503
Guangyao Zhai,Yuanyuan Liu,Yuyin Mao,Honggang Zhang,Lingtong Lin,Yujie Li,Zeyan Wang,Hefeng Cheng,Peng Wang,Zhaoke Zheng,Ying Dai,Baibiao Huang
CO 2 cycloaddition reaction from propylene oxide and CO 2 to cyclic carbonates is a desirable process to become carbon neutral. Photo energy can decrease the temperature and pressure needed for this reaction according to our previous results. However, the relationship between Lewis acidity and the photophysical process needs to be clarified and optimized. Hence, in this work, Zn is introduced into UiO-bpydc via the coordination of Zn with the bipyridyl group in bpydc. It is found that the introduction of Zn not only effectively activate propylene oxide, but also promote ligand to metal charge transfer (LMCT) process, which ultimately is beneficial for CO 2 activation. However, Ce plays a negative effect under light irradiation. namely, the presence of Ce facilitates the energy transfer process rather than the LMCT process.
研究领域:
材料科学
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催化化学
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光催化
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Fangfang Li,Xiaofang Hou,Wei Fu,Jinjin Wang,Ying-Hua Zhou
The efficient transformation of CO 2 into high-value chemicals remains a significant challenge, particularly in the design of heterocatalysts capable of simultaneous multi-site activation towards the substrate. In this work, we develop the novel Zr-MOF catalysts incorporating both cobalt(II) meso-tetra(4-carboxyphenyl)porphine (CoTCPP) complex and the imidazolium bromide-based ionic liquid (IL) containing different alkyl chain (RImBr), where R = Et, Pr, Bu, and Pe), denoted as CoTCPP-UiO-66-IL(RImBr). The catalysts were synthesized through a solvothermal method followed by a post-synthetic modification. Among the prepared catalysts, CoTCPP-UiO-66-IL(BuImBr) demonstrated exceptional performance on the solventless and cocatalyst-free conversion of epichlorohydrin into chloropropene carbonate, achieving a remarkable 99% yield under mild conditions (90 °C and 1.0 bar CO 2 ). This outstanding catalytic efficiency was attributed to the synergistic effects of the dual Lewis-acid active sites offered by Zr-MOF node and the integrated CoTCPP complex, the strong nucleophilicity resulting from the incorporated imidazolium bromide-type IL, and the improved CO 2 adsorption capacity. Additionally, the CoTCPP-UiO-66-IL(BuImBr) catalyst exhibited excellent recyclability and broad substrate versatility in epoxide cycloaddition. These findings provide valuable insights into the development of multifunctional MOF-based heterogeneous catalysts with high activity and sustainability for CO 2 conversion applications.
研究领域:
材料科学
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催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Yongjian Wei,Ying Li,Yunfei Xu,Yuze Zu,Yinghui Sun,Tong Xu,Haiou Liang,Jie Bai
Exploring the impact of metal oxide crystal facets on the cycloaddition reaction of CO 2 with epoxides is meaningful because pure metal oxides exposing specific crystal facets show considerable promise as catalysts for industrial applications. In this study, we developed a simple strategy to prepare single-crystal ZnO nanosheet materials with controllable crystal facets through hydrothermal synthesis, followed by pyrolysis under different atmospheres. Studies revealed that the formation of ZnO single-crystal nanosheets involves the decomposition of the precursors and an ordered phase transition. Based on the quantitative correlation between oxygen vacancies, surface Zn, and the catalytic activity of ZnO (002) with varying numbers of oxygen vacancies, together with TPD, Py-IR, in-situ EPR, fluorescence spectroscopy characterizations, and DFT calculations, a synergistic mechanism between oxygen vacancies and surface Zn was proposed. Specifically, oxygen vacancies are the active sites for CO 2 , whereas saturated coordination surface Zn atoms activate epoxides. At 125 °C, 2 MPa, and 4 h, 93.3 % yield of the product was achieved using only 5 mg of the optimal ZnO catalyst. The excellent performance, stability, and applicability of single-crystal nanosheets make them ideal candidates for industrial applications. This study provides a new insight into the catalytic mechanisms of CO 2 cycloaddition over metal oxides.
研究领域:
材料科学
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催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2014
·Vol. 38
·期 7
·3078-3083
·
IF 3.159
Dan Kong,Yanyan Liu,Juan Zhang,Hongbian Li,Xiangyu Wang,Guangyu Liu,Baojun Li,Zheng Xu
The research on the heterogeneous catalytic synthesis of tetrazoles has attracted great attention. In this paper, a tungsten atom-containing AlPO-5 microporous molecular sieve (termed as WAlPO-5) was designed and synthesized by the incorporation of tungsten atoms into the AlPO-5 skeleton with triethylamine as a structure template from pseudoboehmite, H3PO4 and tungstophosphoric acid. The incorporation of tungsten atoms into the AlPO-5 skeleton has been demonstrated by systematic characterizations. WAlPO-5 can be used as an efficient heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles by [3+2] cycloaddition from nitriles and sodium azide. As a novel heterogeneous catalyst, WAlPO-5 exhibits a high catalytic activity, a superior cycling stability and an excellent substrate applicability. The significant advantages of WAlPO-5, such as the simple procedure and the mild reaction conditions and as an alternative to those corrosive, hazardous and polluting homogeneous catalysts, warrant its potential application in industrial processes.
研究领域:
化学
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Yi Liu,Ying Chen,Shuang Ma,Xianlong Liu,Xiangwen Zhang,Ji-Jun Zou,Lun Pan
High-energy–density (HED) fuels have attracted extensive attention for volume-fixed aerospace vehicles because they can provide more propulsion energy to increase the payload and range of aerospace vehicles. Herein, we report a route for synthesis of HED fuel, pentacyclo[8.2.1.1 4,7 .0 2,9 .0 3,8 ]tetradecane (PCTD) with strained structure, by photoinduced intermolecular [2 + 2] cycloaddition of norbornene (NBE). The triplet quenching and phosphorescence quenching results indicate that NBE cycloaddition is conducted through the photosensitized processes containing triplet–triplet energy transfer, cyclization and relaxation. The reaction conditions are optimized to obtain the high photocatalytic activity, with the NBE conversion and PCTD selectivity reaching 78.7% and 94.4%, respectively. Moreover, a kinetic model is proposed with the reaction rate equation being correlated with the incident light flux, with the pseudo reaction kinetics parameters and reaction rate equations obtained. Importantly, PCTD shows high density of 1.024 g/mL and high volumetric net heat of combustion of 42.98 MJ/L, much higher than those of JP-10. In addition, blending with JP-10 or QC can significantly improve cryogenic properties of blended fuels, which is very promising for the practical application.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CLAY SCIENCE
·
2022
·
IF 5.907
Jiangtao Peng,Ruifeng Guo,Xiongxi Shi,Peiping Zhang,Fagui Qiu,Wenqing Li,Cundi Wei,Shiding Miao
A type of clay-supported catalysts was developed for cycloaddition of CO 2 by immobilizing metal-free ionic liquids (IL) on ball clay (BC) via a one-step strategy. The metal-free IL was loaded on the surface of BC via thermal and acid treatment. The synthesized materials (IL@P-BC) were characterized by Fourier transform infrared spectroscopy (FTIR), N 2 adsorption-desorption, and transmission electron microscopy (TEM). The composite IL@P-BC demonstrated excellent catalytic performance (yield 94.0%, selectively >99%) for coupling of CO 2 with epoxides to produce cyclic carbonates under the lack of any co-catalyst. The good recyclability and excellent suitability were obtained for the composite IL@P-BC. These experimental analyses deepen comprehension of the rational design of clay-based catalysts for CO 2 cycloaddition, further confirmed ball clay was a promising support.
研究领域:
化学工程
·
环境科学
✓ 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）