JOURNAL OF MOLECULAR STRUCTURE
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2017
·
IF 1.753
Yun Bai,Po Yang,Tao Wang,Yi Gu
This work aims at probing the formation of hydrogen bonds in the blends of polybenzoxazines and additional hydrogen-bond donor moieties-containing compounds. Based on experimental study and computer simulations, we found that the dominant hydrogen bonds of p -cresol-aniline-based dimer ( p C-a-D) and polybenzoxazines (P p C-a) were OH⋯N while N,N ′-(pyridine-2,6-diyl)diacetamide (DAA) was NH⋯O C hydrogen bond. After blending p C-a-D or P p C-a with DAA, additional hydrogen bonds formed, i.e. , OH⋯O C and OH⋯ NH. Moreover, the total quantity of hydrogen bonds of the blends increased. These results suggested that hydrogen bonds formed between polybenzoxazines and the additional hydrogen-bond donor moieties-containing polymers or compounds, and furthermore would be desirable to foster the promoted performance. This novel insight about polybenzoxazine blends is anticipated to help researchers explore more blends of polybenzoxazines with excellent properties.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Jiangping Jing,Zhuoyuan Chen,Chang Feng,Mengmeng Sun,Jian Hou
Photoelectrochemical cathodic protection is emerging as a green and environmental method to protect metals against corrosion. Graphitic carbon nitride (g-C 3 N 4 ) shows great application potential in this area because of its high efficiency, high stability and low cost. However, the pristine g-C 3 N 4 shows amphoteric properties, resulting in its failure in providing photoelectrochemical cathodic protection for the coupled metal in NaCl solution. In this work, a K&I co-doping technique was performed to modulate the band structure of g-C 3 N 4 , and an n-type g-C 3 N 4 (n-C 3 N 4 ) was obtained. The changes in the molecular structure were studied by SEM, HRTEM , XRD , EDS, XPS and FT-IR technologies. The n-type semiconductor characteristics were verified by the photoinduced i-V curves, SKP potential distributions and pH drift techniques. The n-C 3 N 4 can generate positive photocurrent in the whole investigated potential range, making it able to provide photoelectrochemical cathodic protection for the coupled 316L stainless steel in NaCl solution. This work is very helpful for promoting the application of g-C 3 N 4 in the fields of the photoelectric conversion and the photoelectrochemical cathodic protection.
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JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Chen Ling,Zixi Ren,Mengmeng Wei,Fei Tong,Yuwei Cheng,Xiaopeng Zhang,Fuqiang Liu
Inorganic complexants, such as ammonia (AA) and pyrophosphate (PP), are often present alongside heavy metal ions in alkaline plating rinsing wastewater. We investigated the removal capacity of Ni(II) from waters containing [Ni-xNH 3 -yP 2 O 7 ] n complexes by chelating and ion-exchange resins in sole and dual-ligand systems. D463 (containing iminodiacetic groups) and PAMD (possessing polyamine groups) exerted superior performance under all conditions. Ni(II) adsorption on D463 decreased with AA and PP by 10.3% and 64.4%, respectively. Conversely, the adsorption on PAMD increased by 57.3% and 75.8%, respectively. PAMD exhibited high selectivity toward anionic [Ni-PP] species over free PP. More Ni(II) was captured by PAMD in the dual-ligand systems than sole systems, while the case for D463 was opposite. As confirmed by species tracking and DFT/XPS analyses, complexes breaking-Ni 2+ capture was the dominant mechanism for D463, while the dual-site (non-charged and protonated amines) interactions with NiP 2 O 7 2– on PAMD promoted its adsorption. The tandem combination D463-PAMD was the optimal mode to remove the most Ni(II). The actual wastewater test demonstrated that >210 BV effluent met the limit of 0.1 mg Ni(II)/L and the eluent contained 15 g Ni(II)/L. This study guides the application of chelating adsorption processes in the advanced treatment of plating rinsing wastewaters.
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COLLOID AND POLYMER SCIENCE
·
2015
·Vol. 293
·期 9
·2617-2624
·
IF 1.865
Yan Zhihu,Dai Caili,Zhao Mingwei,Zhao Guang,Li Yuyang,Wu Xuepeng,Liu Yifei,Du Mingyong
Dual-stimulated wormlike micelles regulated by pH and temperature in a surface active ionic liquid system comprising of a cationic surfactant ( N -cetyl- N -methylpyrrolidinium bromide (C 16 MDB)) and an aromatic dibasic acid (pyrocatechol) were investigated. Such a system can be reversibly switched between liquid-like and gel-like states on adjusting the solution pH value. The rheology, light scattering techniques and cryogenic-transmission electron microscopy (cryo-TEM) results show the growth of spherical micelles into long and entangled wormlike micelles was responsible for the changes in flow properties such as high viscosity, shear-thinning behaviour and Maxwell-type dynamic rheology. The nuclear magnetic resonance results reveal the binding capacity of pyrocatechol to C 16 MDB is proposed as the key factor of the unusual rheological and micellar responses of this pH-stimulated system. In addition, with the increase of temperature, molecular motion of surfactant molecules becomes more active, which endow the property of thermo-stimulated to the surface active ionic liquid system.
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HIGH PERFORMANCE POLYMERS
·
2017
·
IF 1.179
Lala Rukh Sidra,Nafeesa Mushtaq,Guofei Chen,Xingzhong Fang
A series of poly(N-arylene benzimidazole ether imide) copolymers PEIBIs were prepared from 1H,3′H-5,5′-bis-benzimidazole, bisphenol-A and 4,4′-bis(4-fluorophthalimido)diphenyl ether by nucleophilic displacement polymerization. The resulting copolymers PEIBI(10–90) demonstrated moderate to good solubility in polar aprotic solvents and high glass transition temperatures (Tgs) of 228–336°C, good thermal stability with 10% weight loss temperatures in the range of 503–548°C. All copolymer films showed good mechanical properties with tensile strengths of 101–130 MPa, tensile moduli of 3.3–4.0 GPa, elongations at break of 5–7%, and also presented low water uptake (0.15–0.34%). The wide-angle X-ray diffraction results revealed the amorphous nature of copolymers. The copolymer PEIBI-80 showed good balance in solubility, thermal and mechanical properties.
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ChemSusChem
·
2015
·Vol. 8
·期 12
·2066-2072
·
IF 7.657
Yehong Wang,Jian Zhang,Jing Liu,Chaofeng Zhang,Zhixin Zhang,Jie Xu,Shutao Xu,Fangjun Wang,Feng Wang
Graphical CO 2 -mediated reactions: CO 2 -mediated metathesis reactions between amines and DMF to synthesize formamides are described. The N -formylation of amines to formamides is achieved by activating amines, not DMF, via a C N and N H bond metathesis reaction. Using this method, primary, secondary, aromatic, and heterocyclic amines as well as diamines can be obtained with good to excellent formamide yields. Herein, we report CO 2 -mediated metathesis reactions between amines and DMF to synthesize formamides. More than 20 amines, including primary, secondary, aromatic, and heterocyclic amines, diamines, and amino acids, are converted to the corresponding formamides with good-to-excellent conversions and selectivities under mild conditions. This strategy employs CO 2 as a mediator to activate the amine under metal-free conditions. The experimental data and in situ NMR and attenuated total reflectance IR spectroscopy measurements support the formation of the N -carbamic acid as an intermediate through the weak acid–base interaction between CO 2 and the amine. The metathesis reaction is driven by the formation of a stable carbamate, and a reaction mechanism is proposed.
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JOURNAL OF CATALYSIS
·
2021
·
IF 7.92
Jianguo Liu,Shanshan Lin,Jiangming Sun,Longlong Ma
Transition metal-catalyzed semi-hydrogenation of alkynes has become one of the most popular methods for alkene synthesis. Specifically, the noble metal Pd, Rh, and Ru-based heterogeneous catalysts have been widely studied and utilized in both academia and industry. But the supported noble metal catalysts are generally suffering from leaching or aggregation during harsh reaction conditions, which resulting low catalytic reactivity and stability. Herein, we reported the facile synthesis of nitrogen doped graphene encapsulated Pd catalyst and its application in the chemo-selective semi-hydrogenation of alkynes. The graphene layer served as “bulletproof” over the active Pd Nano metal species, which was confirmed by X-ray and TEM analysis, enhanced the catalytic stability during the reaction conditions. The optimized prepared Pd@N/C catalyst showed excellent efficiency in semi-hydrogenation of phenylacetylene and other types of alkynes with un-functionalized or functionalized substituents, including the hydrogenation sensitive functional groups (NO 2 , ester, and halogen).
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ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Chunguang Chen,Liangyu Li,Junming Su,Congcong Zhang,Xiang Chen,Tao Huang,Aishui Yu
Although dimethylsulfoxide (DMSO) solvent has been widely researched in rechargeable lithium-oxygen (Li-O 2 ) batteries , high polarization voltage and low rate capability limited its application. In this work, we reported a DMSO-based electrolyte system by adding N, N-dimethylacetamide (DMA) to adjust its physical and electrochemical properties. The ionic conductivity , viscosity, oxygen solubility and diffusion coefficient of the mixed electrolytes as well as their electrochemical performance in Li-O 2 batteries are researched. The electrochemical tests show that the optimized DMSO/DMA volume ratio is 30 to 70 based on the rate performance and polarization voltage of the cell. Compared with that of the pure DMSO-based electrolyte, the cell with the mixed electrolyte shows improved rate capability and reduced charge-discharge over-potential. When increasing current density from 0.2 to 0.5 mA cm −2 , the capability retention improves from 32% to 59%. Meanwhile, the charge-discharge voltage gap drops from 1.4V to 0.9V at a current density of 0.2 mA cm −2 . The improved electrochemical performance could be attributed to low viscosity, high oxygen solubility and diffusion coefficient as well as the low charge-transfer resistance with the mixed electrolyte.
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JOURNAL OF CHROMATOGRAPHIC SCIENCE
·
2017
·Vol. 55
·期 6
·662-668
·
IF 0.984
Ma Xiaowei,Feng Fan,Yang Yang,Dang Xueping,Huang Jianlin,Chen Huaixia
Fe3O4@MIL-100 (MIL, Material Institut Lavoisier) core–shell magnetic microspheres were prepared and applied as the sorbent for the magnetic solid phase extraction (MSPE) of N,N-diethyl-m-toluamide (DEET) in baby toilet water for the first time. The synthesized magnetic metal–organic frameworks were characterized by transmission electron microscope, infrared spectroscopy and thermogravimetric analysis. The functionalized magnetic microparticles showed excellent dispersibility in aqueous solution. The MSPE conditions were investigated in detail. Under the optimized conditions, an MSPE–high performance liquid chromatography method for the determination of DEET was developed. The method was linear in the concentration range from 5 to 500 μg L−1 for DEET in baby toilet water and good linearity (r2 > 0.9998) was obtained for the calibration curve. The limit of detection was 1.5 μg L−1. Both the intra-day and inter-day precisions (relative standard deviations) were <3%.
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PubMed
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REACTIVE & FUNCTIONAL POLYMERS
·
2011
·
IF 2.546
Lei Li,Xiaoying Du,Jianping Deng,Wantai Yang
Optically active macroporous poly( N -isopropylacrylamide) (PNIPAM) hydrogels were synthesized via free radical copolymerization of NIPAM, helical macromonomer, and cross-linker N , N ′-methylenebisacrylamide. The helical macromonomer not only contained catechol groups but also vinyl groups in side chains. Polyethylene glycols were used as pore-forming agent to give rise to macroporous structures in the optically active hydrogels. The hydrogels were characterized by FT-IR, SEM, DSC , swelling ratio and circular dichroism spectra analyses and exhibited the expected optical activity and macroporous architectures. The chiral resolution tests demonstrated the preferential adsorption of the hydrogels towards d -tryptophan and d -phenylalanine in the corresponding two amino acid enantiomers .
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TETRAHEDRON
·
2024
·
IF 2.1
Nan Wang,Yuanyuan Huang,Mengke Wang,Weichun Huang,You Zi
Herein, a new approach for the synthesis of ( Z )- N -alkenyl-2-pyridones from 2-pyridones and propiolates using phosphine catalysis under mild conditions is reported. This dual Z -diastereoselective and N -selective reaction demonstrates excellent selectivity, yielding sole ( Z )- N -alkenyl-2-pyridones. Furthermore, scale-up studies confirm its practical applicability, with consistent efficiencies observed.
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NANO
·
2022
·
IF 1.438
Jie Cao,Weimin Hu,Qiuyan Li,Guo Lv,Weifeng Chen,Xiang Liu
Utilization of nonprecious metals to replace precious metals in the catalytic hydrolysis of hydrogen storage materials causes wide attention. Herein, nonprecious bimetallic nanoparticles loaded on N-doped graphene quantum dots (Co-Ni/N-GQDs) have been synthesized and applied in the hydrolysis of NH 3 BH 3 for the first time. It is demonstrated that Co-Ni/N-GQDs exhibit the obvious bimetallic synergies in the hydrolysis of NH 3 BH 3 , and the total turnover frequency (TOF) value reaches 19.94 mol H2 ⋅ mol Cat − 1 ⋅ min − 1 via the optimized design. This work first explored the catalytic performance for the nonprecious bimetallic nanoparticles loaded on N-GQDs in the hydrolysis of NH 3 BH 3 , greatly facilitating the development of both nonprecious metals and N-GQDs in the hydrogen evolution.
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危险品化学品经营许可证（带存储）