CHINESE JOURNAL OF POLYMER SCIENCE
·
2015
·Vol. 33
·期 11
·1618-1624
·
IF 1.835
Hu Wei,Cao Jing,Huang Yi-ling,Liang Sai
The anionic polymerization of N -vinylcarbazole (NVC) by using optically active anionic initiators such as the lithium salts of ( S )-1-(9H-fluoren-2-yl)-4-isopropyl-4,5-dihydrooxazole (( S )-1-FIDH) and ( S )-2-(9H-fluoren-2-yl)-4- isopropyl-4,5-dihydrooxazole (( S )-2-FIDH) and complexes of (-)-Sparteine with n -butylithium (n-BuLi-(-)-Sp) or fluorenyl lithium (FILi-(-)-Sp) was achieved. The yield and specific rotation of poly( N -vinylcarbazole)s (poly(NVC)s) were considerably affected by the molar ratio of ( S )-FIDH to NVC. The highest yield and specific rotation were obtained with Li- ( S )-1-FIDH as an initiator, with a molar ratio of monomer and initiator [M]/[I] = 10/1. The effects of the chiral initiators, type of solvent and the polymerization temperature were investigated. The obtained optical activity of polymers was attributed to asymmetric induction of the chiral initiators.
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高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Yan Li,Mengna Ding,Guoxiang Yang,Lei Wang,Liulin Luo,Yingchun Miao,Yuning Huo
Acinetobacter baumannii ( A. baumannii ) was widely existed in medical wastewater and easily induced infections to threaten the human healthy. We herein reported Ag/CoO-N photocatalyst composites for effective inactivation of A. baumannii . Ag/CoO-N composites were prepared by N-doping to CoO crystal in supercritical fluid followed with photo-reduction of Ag under visible-light irradiation. N-species was incorporated in the crystal structure of CoO, on which uniform Ag nanoparticles were stably deposited. Thus, the satisfactory photocatalytic sterilization of A. baumannii irradiated by visible-light irradiation was attributed to the high capability of light trapping and the efficient separation of photo-charges. Due to photo-induced electrons as the main active species, Ag nanoparticles and CoO-N synergistically realized mineralization of cell membrane, which lead K + ions leak from cell to crack structure of bacteria, the decrease of genetic materials, and the cripple of the self-repair function in bacteria, resulting in the final cell death.
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BIORESOURCE TECHNOLOGY
·
2014
·
IF 5.039
Cuiping Chen,Wenjun Zhou,Daohui Lin
N-nitrosodimethylamine (NDMA) is an emerging carcinogenic disinfection by-product in water environment. Biochars utilized as sorbents for the removal of NDMA from aqueous solution, and the sorption characteristics and mechanism were investigate. Biochars were prepared from bamboo, rice straw and wood sawdust at 300–700 °C. The pseudo-second-order model provided the best fit for the sorption kinetics of NDMA onto biochar and the sorption isotherms were described best with the Slips model. Biochar produced at 500 °C removed NDMA from aqueous solution relatively efficiently, and the bamboo char demonstrated the best sorption potential among the three types of biochars. Solution chemistry such as pH and metal ions did not show obvious effect on NDMA removal. Three sorption mechanisms are suggested for NDMA sorption onto biochars, H-bond attraction between N O and the O-containing moieties, hydrophobic force between CH 3 and the ordered graphitic structure, and partition process of NDMA into the non-carbonization part of biochar.
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PubMed
高影响因子
Heliyon
·
2023
·Vol. 9
·期 4
·e15357
·
IF 4
Xiufeng Wu,Zhaoliu Cao,Jiang Ni,Xiaoyuan Zheng,Lizhen Zhu,Xin wang,Juan Lv,Shijun Zhou,Yongjuan Ding,Ruirong Wu
Mixing different kind inhalation medications for simultaneous inhalation is widely used in the treatment of chronic respiratory diseases, and it can minimize the administration time and improve patient adherence. To our knowledge, it is unclear whether beclomethasone (BDP, Clenil®) can bemixed with acetylcysteine (NAC, Fluimucil®), because the in vitro physico-chemical compatibility and aerosol characteristics of the mixture are unknown. In this study, we investigated physical compatibility, including the appearance, pH, osmotic pressure and chemical stability, as well as aerosol characteristics, including particle size corresponding to 10%/50%/90% of the cumulative percentage of total particle volume ( X 10/ X 50/ X 90), volume median droplet diameter (VMD), mass median aerodynamic diameter (MMAD), fine particle fraction (FPF), fine particle dose (FPD) and geometric standard deviation (GSD), delivery rate, and total delivery of the above solutions. After mixing, there were no significant changes in visual appearance, pH, osmolality and drug content of the mixtures at room temperature for 12 h. The FDP of BDP in the mixture decreased by 16.49%, whereas the NAC increased by 10.85%. The delivery rates of BDP and NAC in the mixture decreased by 66.05% and 45.54%, and total delivery increased by 13.20% and 25.29%, respectively. However, the MMAD, FPF, particle size and GSD of the mixture were almost unchanged. We demonstrated that these admixtures are physico-chemically compatible but that coadministration of beclomethasone with acetylcysteine can markedly affect output and aerosol characteristics.
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PubMed
高影响因子
NANO
·
2019
·
IF 1.293
Hongning Wang,Chao Xu,Yongsheng Zhou,Wenpu Zhao,Jing Zhong,Weiqiu Huang,Ruoyu Chen
Hierarchical N-doped carbon nanotubes (NCTs) with controllable aspect ratios were developed for CO 2 adsorption. In this work, NCTs were synthesized by coating different amounts of 3-aminophenol/formaldehyde resin (APF) on the outer layer of silica nanotubes, carbonizing in N 2 at 700 ∘ C and removing the silica and Ni template by hydrofluoric acid etching. The obtained NCTs were activated by K 2 CO 3 . After activation, micropores on the activated N-doped carbon nanotubes (ANCTs) were enriched, the micro-surface area and pore volume of ANCT-1.0 reached 1195 m 2 g − 1 and 0.45 cm 3 g − 1 , respectively, and the corresponding adsorption capacity increased by 50% (4.50 mmol g − 1 at 0 ∘ C and 1 bar). Moreover, ANCT-1.0 maintained a high stability throughout consecutive adsorption–desorption cycles. The advantages of hierarchical N-doped carbon nanotubes, including their meso–microporous structures, high geometric aspect ratio and good stability, make them valuable and promising materials to capture carbon dioxide.
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Chem Catalysis
·
2022
·
IF 0
Xianhao Zhang,Huijuan Jing,Shiming Chen,Bing Liu,Liang Yu,Jianping Xiao,Dehui Deng
Summary Cyclohexanone oxime (CHO), a key C=N organic compound in the manufacture of nylon 6, is conventionally synthesized via a multistep process that consumes expensive NH 3 and H 2 under harsh conditions. Herein, we report the direct electro-synthesis of CHO from low-cost NO, H 2 O, and cyclohexanone over a carbon catalyst under ambient conditions. A high Faradaic efficiency of 44.8% and a formation rate of 10.7 mg cm −2 h −1 for CHO were achieved at −0.4 V versus the reversible hydrogen electrode through optimizing the surface hydrophobicity of the catalyst to facilitate diffusion of reactants. Controlled experiments and 15 N-labeling tests verified that the nitrogen in the CHO product originates from NO. Density functional theory calculations showed that the armchair edge of carbon could be the active site with a reaction mechanism following NO → NO∗ → HNO∗ → HNOH∗ → NH 2 OH → CHO. This work suggests a direct, green, and low-cost synthesis strategy for high-value CHO from pollutant NO.
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EUROPEAN POLYMER JOURNAL
·
2018
·
IF 3.741
Xi Chen,Xiaojun Liu,Congcong Miao,Pengfei Song,Yubing Xiong
Inimer bears a polymerizable vinyl group and a reactable group, and thus has great potentials in the synthesis of branched and functional polymers. Herein, a strategy was developed for the synthesis of ionic liquid (IL)-like inimer containing a trithiocarbonate moiety and a styryl group. The newly-developed IL-like inimer could be facilely achieved via the neutralization reaction using a carboxyl-contained chain transfer agent (CTA) and an alkaline IL monomer. The IL-like inimer was characterized through proton and carbon nuclear magnetic resonance spectroscopy ( 1 H and 13 C NMR), Flourier transform infrared spectroscopy (FT-IR) and Mass spectroscopy. Moreover, the reversible addition-fragmentation chain transfer (RAFT) polymerization of N-isopropylacrylamide (NIPAM) mediated by the as-prepared IL-like inimer was investigated. The results revealed that branched PNIPAM with tunable molecular weight and degree of branching (DB) could be prepared. Additionally, lower critical solution temperature (LCST) of branched PNIPAM could be adjusted through the feed ratio of IL-like inimer and the monomer in the polymerization process. As a result, our study offers a new technique for the design of functional inimer, as well as broadens the application of ILs in the polymer field.
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高影响因子
ChemistrySelect
·
2025
·Vol. 10
·期 43
·e05445
·
IF 2
Hui Li
Direct methanol fuel cells (DMFCs) face significant challenges due to sluggish methanol oxidation reaction (MOR) kinetics and catalyst poisoning by carbon intermediates (e.g., CO ads ). To address this, we rationally designed nitrogen-doped carbon (NC) carriers with tailored N-configurations (pyridinic-N, pyrrolic-N, and graphitic-N) via controlled pyrolysis temperatures (700–1000 °C) and anchored Pt nanoparticles (NPs) to enhance metal-support interaction (MSI). The NC-900 carrier achieved optimal N-configuration distribution (56.7% pyridinic-N, 25.2% pyrrolic-N, 18.1% graphitic-N) and the highest defect density ( I D /I G = 1.12), enabling ultra-dispersed Pt NPs (1.69 nm) and strong electron donation to Pt. XPS confirmed a 61.2% Pt° content in Pt/NPC-900, facilitating efficient methanol adsorption/activation. In alkaline media, Pt/NPC-900 delivered a record mass activity of 4687.5 mA mg −1 Pt - 4.36 × higher than Pt/PC—along with exceptional stability (79.6 % current retention after 500 cycles). In situ Raman spectroscopy revealed a non-CO pathway, circumventing poisoning intermediates. This work establishes a precise N-configuration engineering strategy to optimize MSI for next-generation DMFC catalysts. Graphical Schematic diagram for the preparation of N-doped carbon-supported Pt nanoparticles catalysts by chemical reduction method.By adjusting the roasting temperature, it is possible to control the proportion of different N-configuration distributions. This enables effective control of the dispersion degree and electronic properties of the active metal Pt, thereby enhancing the activity and stability of the catalyst during the alkaline methanol oxidation reaction.
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高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2015
·
IF 5.056
Liang Cheng,Li-Ping Zhu,Pei-Bin Zhang,Jian Sun,Bao-Ku Zhu,You-Yi Xu
Here we demonstrate the tunable molecular selectivities and corresponding mechanisms of poly(N-vinyl imidazole) (PVI) gel-filled membranes prepared by UV initiated graft polymerization of N-vinyl imidazole from ultraporous polysulfone (PSf) substrate. The separation performance was investigated in detail by extensive filtration tests with various organic molecules in water of varying pH and also in salt or ethanol aqueous solution. The variation of membrane water permeability and solute rejection with the feed pH was attributed to the sensitive pore size and charge characteristics of the membranes upon reversible protonation of the confined PVI gel. The separation results discerned three main mechanisms, i.e. size exclusion (sieving), electrostatic repulsion (Donnan exclusion) and adsorption. The rejection of the neutral molecules and the large dye molecules was mostly ascribed to size exclusion, while that of the small charged solutes was dominated by the electrostatic interactions including repulsion for cationic ones and attraction for anionic ones (causing specific adsorption). Typically, at pH 3 the protonated membranes rejected ~90% of the small cationic Vitamin B 1 (VB 1 ) and 100% of the anionic Sunset Yellow (SY) before adsorption saturation, in contrast to less than ~20% rejection of the neutral Vitamin B 2 (VB 2 ) having similar molecule size. In the high concentration salt or ethanol solution the membranes still maintained molecular sieving capability. Most notably, the separations of solute mixtures were indeed achieved, depending on the membrane parameters, the solute characteristics as well as the filtration conditions. The PVI gel-filled membranes developed in this work are promising in some specified or environment-sensitive molecular level separations.
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高影响因子
PLANT PHYSIOLOGY AND BIOCHEMISTRY
·
2018
·
IF 2.718
Chen Geng,Tengfei Zhao,Chunxian Yang,Qiaozhuo Zhang,Feng Bai,Junlan Zeng,Fangyuan Zhang,Xiaoqiang Liu,Xiaozhong Lan,Min Chen,Zhihua Liao
N -methylputrescine is the precursor of nicotine and pharmaceutical tropane alkaloids such as hyoscyamine . Putrescine N -methyltransferase (PMT) catalyzes the N -methylation of putrescine to form N -methylputrescine. While the role of PMT in nicotine biosynthesis is clear, knowledge of PMT in the biosynthesis of tropane alkaloids (TAs) and the regulation of polyamines remains limited. We characterized a PMT gene from Hyoscyamus niger , designated HnPMT that was specifically expressed in roots, especially in the secondary roots and dramatically induced by methyl jasmonate (MeJA). The GUS gene was specifically expressed in Arabidopsis roots or in the vascular tissues , including pericycles and endodermis , of the H. niger hairy root cultures , when it was driven by the 5′-flanking promoter region of HnPMT . The recombinant HnPMT was purified for enzymatic assays. HnPMT converted putrescine to form N -methylputrescine, as confirmed by LC-MS. The kinetics analysis revealed that HnPMT had high affinity with putrescine but low catalytic activity, suggesting that it was a rate-limiting enzyme . When HnPMT was suppressed in the H. niger plants by using the VIGS approach, the contents of N -methylputrescine and hyoscyamine were markedly decreased, but the contents of putrescine, spermidine and a mixture of spermine and thermospermine were significantly increased; this suggested that HnPMT was involved in the biosynthesis of tropane alkaloids and played a competent role in regulating the biosynthesis of polyamines . Functional identification of HnPMT facilitated the understanding of TA biosynthesis and thus implied that the HnPMT-catalyzed step might be a target for metabolic engineering of the TA production in H. niger .
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2013
·Vol. 131
·期 7
·
IF 1.395
Bojian Hu,Xiaoqin Chen,Yan Zuo,Zuliang Liu,Xiaodong Xing
Bi-functional antibacterial material was prepared by co-grafting N -halamine and quaternary ammonium salt monomers from cellulose fiber. The grafted fiber was characterized by Fourier transform infrared spectra, and X-ray photoelectron spectra. The N -halamine derived from the precursor 4-[(acryloxy)methyl]-4-ethyl-2-oxazolidinone via chlorination treatment and the oxidative chlorine (Cl + ) leaching behavior were investigated. The antibacterial activities of singly (only QAs-functionalized or only Cl + -releasing) and dual (QAs-functionalized and Cl + -releasing) functional cellulose fibers were tested against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus . Compared to singly functionalized formulations, the bi-functional cellulose fiber exhibited excellent and rapid bactericidal performance against both E. coli and S. aureus . © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40070.
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高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Yanhua Li,Shuhuan Wang,Kuo Zhang,Dongjia Wang,Qun Li,Yuekai Xue
Herein, the N-doped Ti 3 C 2 /TiO 2 nanostructure has been synthesized via hydrothermal treatment and following annealing in NH 3 . TiO 2 nanoparticles in-situ grow on the surface of Ti 3 C 2 spontaneously, resulting in the stable electron transport between TiO 2 and Ti 3 C 2 . Besides, Ti 3 C 2 nanosheets as conductive substrates make up for the poor conductivity of TiO 2 . The doping of N in Ti 3 C 2 /TiO 2 composite further improves the electrical conduction. The ultimate N-doped Ti 3 C 2 /TiO 2 composite achieves a higher specific capacitance of 737.4 F g −1 than Ti 3 C 2 (324.4 F g −1 ) at 0.5 A g −1 . More importantly, the composite displays a high specific capacitance retention of 81 % over 12,000 cycles. Besides, the assembled symmetrical supercapacitor (SSC) manifests an excellent specific capacitance of 236.4 F g −1 at 1 A g −1 and a comparable energy density of 32.8 Wh kg −1 at the power density of 500 W kg −1 . This work provides promising guidance for the fabrication of durable electrodes for energy storage application.
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危险品化学品经营许可证（带存储）