GREEN CHEMISTRY
·
2019
·Vol. 21
·期 8
·2129-2137
·
IF 9.405
Di Liu,Ping Yang,Hao Zhang,Minjie Liu,Wenfei Zhang,Dongmei Xu,Jun Gao
A non-noble heterogeneous catalyst – a Co, N and C composite encapsulated carbon nanotube grown in situ on the surface of activated carbon (Co–N–C/CNT@AC) – was fabricated via the pyrolysis–reduction process. Co–N–C/CNT@AC catalyzed the reductive coupling of structurally diverse nitroarenes and alcohols to imines and secondary amines under exogenous base- and solvent-free conditions. BET, TEM, SEM, XRD and XPS characterization showed that the exceptional catalytic property of Co–N–C/CNT@AC could be explained by its nanostructure, Co–N and basic N species. Our protocol had advantages of low cost, environment-friendliness, and good applicability. Furthermore, a reaction route of nitroarenes, amines and alcohols as the starting materials was proposed to improve the atom economy of the reductive coupling of nitroarenes with alcohols.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Jun Jiang,Teng Li,Kexin Huang,Guangyu Sun,Jing Zheng,Jinlong Chen,Weiran Yang
As a bio-based platform chemical, it is desirable to convert levulinic acid (LA) to varieties of value-added biochemicals. n-Butane, mainly from nonrenewable fossil resources, is a basic chemical to produce some important chemicals, such as butadiene and ethylene. In this paper, 95.5% yield of n-butane was obtained from LA in one-step over base-treated Pt/C at around 300 °C in 4 h. The reaction pathway was confirmed to be the hydrodeoxygenation of LA to valeric acid (VA) and then the VA decarboxylation to n-butane by kinetic studies. Base-treated Pt/C had better reactivity due to its improved decarboxylation activity. Detailed characterization of the catalyst revealed that the Pt particle size is the key reason for the activity improvement, and further studies showed that Pt nanoparticles with a size of 2–4 nm showed the highest decarboxylation activity. This is the first report on the direct conversion of LA to n-butane.
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Polymer Chemistry
·
2018
·Vol. 10
·期 5
·619-626
·
IF 4.927
Houbo Zhou,Christopher M. Plummer,Huaan Li,Huahua Huang,Pengfei Ma,Le Li,Lixin Liu,Yongming Chen
Previously, we developed amination modification of polyethylene by metal-free organocatalytic reaction. Here, we applied this chemistry to modify isotactic polypropylene (PP) to investigate the regioselectivity to different carbons. Specifically, this reaction was conducted in tetrachloroethane at 100 °C under a nitrogen protection where C–N bonds were selectively generated from the tertiary C–H bonds of the PP backbone in the presence of N-hydroxyphthalimide (NHPI) and bis(2,2,2-trichloroethyl) azodicarboxylate (BTCEAD). The grafting content of BTCEAD was as high as 4.7 units per 100 propylene units. Thus, a methodology for the regioselective post-functionalization of PP without metal catalysts has been developed. The obtained PP-g-BTCEAD was sequentially used as an atom transfer radical polymerization (ATRP) macro-initiator to graft polymers, such as polystyrene (PS) and poly(methyl) methacrylate (PMMA). The grafting polymerization was unequivocally proved by multiple characterization methods. The graft copolymers were applied as phase compatibilizers to improve blending of PP with PS and PMMA.
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RSC Advances
·
2014
·Vol. 5
·期 9
·6666-6674
·
IF 3.708
Linlin Duan,Wei Huang,Yatao Zhang
N-Halamine grafted halloysite nanotubes (N-halamine@HNTs) were used as an antibacterial agents to fabricate polyethersulfone (PES) ultrafiltration (UF) hybrid membranes. N-Halamine@HNTs were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS). The chemical compositions, storage modulus, tan δ, morphology and performance of the membranes were characterized by attenuated total reflection-Fourier transform infrared spectra (ATR-FTIR), dynamic mechanical analysis (DMA), water contact angle, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), overall porosity and pore size measurements. The results showed that the hydrophilicity of the membranes was improved greatly after adding N-halamine@HNTs. Water flux of the hybrid membrane could reach as high as 248.3 L m−2 h−1 when the content of N-halamine@HNTs was 1.0 wt%. In addition, the antibacterial test indicated that the hybrid membranes showed good antibacterial activity against E. coli.
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CATALYSIS LETTERS
·
2018
·Vol. 148
·期 8
·2418-2431
·
IF 2.911
Sun Rong,Huang Wan,Zhang Qian,Hong Jun-ming
Abstract This study developed nitrogen-doped graphene/Pt/TiO 2 (N-GN/Pt/TiO 2 ) as anode to effectively degrade aminophenol (APAP) in electrocatalytic process. Due to the different physicochemical properties of graphene with various N species loading, the efficiency of catalysts was novelty discussed. The morphology, N-doped content/species, and the graphene defects of the catalyst were analyzed by TEM, FTIR, XPS, EA, and Raman spectroscopy. The results show that the doping morphology of the N atoms gradually shifted from pyridinic N and pyrrolic N to graphitic N with increased hydrothermal time, in order to decrease the defect degrees and redox activity. However, the conductivity of material increased with the graphitic N generation. The best APAP degradation efficiency (100% with 20 mA, 1 g/L NaCl, and initial pH 3.0) can be achieved with 1.5-N-GN/Pt/TiO 2 (mainly pyridinic N and pyrrolic N doping). A detailed investigation was conducted to determine the oxidation intermediates of APAP using GC-MS analysis. Finally, a possible degradation pathway was proposed. Graphical Abstract
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CHINESE JOURNAL OF CATALYSIS
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2013
·
IF 1.304
Ming Jin,Dan Zhao,Guozhen He,Yao Tong,Shiqing Han
An efficient method has been developed for the N -arylation of a variety of water-soluble amino alcohols (1.2 mmol) with aryl iodides (1.0 mmol) in water under CuI-catalyzed conditions. The reaction was conducted via substrate-promoted action and did not require an additional ligand or phase-transfer catalyst, and afforded the desired N -aryl amines in acceptable to excellent yields (64%–93%) under mild reaction conditions with a small excess of the amino alcohol.
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APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Meinan Wan,Mo Xiong,Neng Li,Baoshun Liu,Shuo Wang,Wai-Yim Ching,Xiujian Zhao
Research on monoclinic (M1) phase of VO 2 has attracted a great of interest for smart coating applications due to its exceptional thermochromic property. Herein, we report the results using a novel approach to synthesize N-doped VO 2 (M1) thin films with high purity by heat treatment in NH 3 atmosphere. The N dopant in the film can be regulated by varying NH 3 concentration during the annealing process. We find that the N atoms are located at the interstitial sites or substitute oxygen atoms, and the V-N bonds in the VO 2 thin films increase with NH 3 concentration. The metal to insulator transition (MIT) temperature ( τ c,h ) of the VO 2 thin film is effectively reduced from 80.0 to 62.9 °C, while the solar modulation efficiency (Δ T sol ) and the modulation efficiency at 2000 nm (Δ T 2000nm ) are 7.36% and 55.6% respectively. The band gap of N-doped VO 2 thin films related to MIT ( E g 1 ) is estimated to be as low as 0.18–0.25 eV whereas the band gap associated with the visible transparency ( E g 2 ) is about 1.50–1.58 eV. Based on the highly accurate first-principles calculations, the E g 1 of VO 2 (M1) is reduced after substituted or interstitial N-doping, while the E g 2 alters with the mode of N-doping, which is excellent agreement with experimental measurement.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2011
·
IF 4.746
Xiaolin Qiu,Wei Li,Guolin Song,Xiaodong Chu,Guoyi Tang
Microencapsulations of n-octadecane with different crosslinked methylmethacrylate-based polymer as shells were carried out by suspension-like polymerizations. 1,4-butylene glycol diacrylate (BDDA), divinylbenzene (DVB), trimethylolpropanetriacrylate (TMPTA) and pentaerythritol tetraacrylate (PETRA) were employed as crosslinking agents. The influences of the type and amount of crosslinking agent, the type of initiator and polymerization temperature on the properties of as-prepared microencapsulated phase change materials (MicroPCMs) have been studied. The MicroPCMs were characterized using Fourier transformed infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Thermal properties and thermal stability of MicroPCMs were investigated by differential scanning calorimetry (DSC) and thermalgravimetric analysis (TGA). Shell mechanical strength was measured by micro/nano-hardness tester. Thermal properties, thermal resistant temperatures as well as shell mechanical strength of MicroPCMs enhanced as the number of crosslinkable functional moieties of the crosslinking agents increased. The MicroPCMs containing 75.3 wt% n-octadecane obtained using PETRA as crosslinking agent has the highest latent heats of melting (156.4 J/g) and crystallization (182.8 J/g) and displays the highest thermal stability and shell mechanical strength. The MicroPCMs prepared with DVB shows a relatively higher shell mechanical strength and heat capacity compared with those prepared with BDDA. Both heat capacity and thermal stability of MicroPCMs prepared by combining 2,2 ′ -azobisisobutyronitrile (AIBN) and redox initiators at 45 °C were lower than that of MicroPCMs prepared with AIBN or benzoyl peroxide (BPO) at 85 °C. Hence, MicroPCMs with crosslinked methylmethacrylate-based polymer as shells, especially crosslinked polymer shells of higher crosslinking density , show a good potential as a solar-energy storage material.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Miao Zhang,Ruijin Zheng,Ying Ma,Ruiping Chen,Xun Sun,Xuan Sun
Three 2D N-rich COFs linked by –C=N– bond, named COF-SDU1, COF-SDU2, COF-SDU3, have been synthesized via the Schiff-base condensation reaction . Tri-(4-formacylphenoxy)-1,3,5-triazine (TRIF) is employed as N-rich aldehyde building block, and p-phenylenediamine (PA), hydrazine hydrate, and terephthalic dihydrazide (TPDH) are as the amine building blocks, respectively, which results in high crystallinity, high BET surface area, and abundant N-atom sites for COF-SDU1, COF-SDU2, and COF-SDU3. COF-SDU1 exhibits large CO 2 uptake of 741 mg g −1 at 298 K under 45 bar, while COF-SDU2 is 484 mg g −1 and COF-SDU3 is only 331 mg g −1 , which are closely related to their specific surface area but irrespective of the absolute N-content. The result clearly reveals the impact of various factors, including N-content, BET surface area and pore size on CO 2 storage performance. It shows that N-content determines capacities at low pressure (<1 bar), BET surface area plays the decisive role under relative low pressure (<25 bar) and large pore size helps enhance the capacity under relative high pressure (>25 bar). Among all factors, BET surface area plays the crucial role in determining the high-pressure CO 2 storage capacity, which is well verified by theoretical modeling.
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Small
·
2022
·Vol. 18
·期 34
·2201556
·
IF 15.153
Yuxin Liu,Cailing Chen,Yiqiang He,Zhe Zhang,Mingbian Li,Chunguang Li,Xiao-Bo Chen,Yu Han,Zhan Shi
Design and development of highly efficient photocatalytic materials are key to employ photocatalytic technology as a sound solution to energy and environment related challenges. This work aims to significantly boost photocatalytic activity through rich indium vacancies (V In ) In 2 S 3 with atomic p–n homojunction through a one-pot preparation strategy. Positron annihilation spectroscopy and electron paramagnetic resonance reveal existence of V In in the prepared photocatalysts. Mott–Schottky plots and surface photovoltage spectra prove rich V In In 2 S 3 can form atomic p–n homojunction. It is validated that p–n homojunction can effectively separate carriers combined with photoelectrochemical tests. V In decreases carrier transport activation energy (CTAE) from 0.64 eV of V In -poor In 2 S 3 to 0.44 eV of V In -rich In 2 S 3 . The special structure endows defective In 2 S 3 with multifunctional photocatalysis properties, i.e., hydrogen production (872.7 µmol g −1 h −1 ), degradation of methyl orange (20 min, 97%), and reduction in heavy metal ions Cr(VI) (30 min, 98%) under simulated sunlight, which outperforms a variety of existing In 2 S 3 composite catalysts. Therefore, such a compositional strategy and mechanistic study are expected to offer new insights for designing highly efficient photocatalysts through defect engineering.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 134
·期 19
·
IF 1.86
Xiaohai Bu,Zewu Zhang,Zusheng Hang,Ying Huang,Yuming Zhou
Novel optically active and racemic poly( N -propargylamides) bearing tyrosine pendants (LPT, DPT, and RPT) were synthesized and characterized. The polymers possessed moderate molecular weights and were thoroughly soluble in common organic solvents. The secondary structure of these three polymers in chloroform was studied and the results indicated that LPT and DPT could adopt helical structures with predominantly one-handed screw sense according to their intense Cotton effect and large specific rotation values, while RPT adopted random coiled polymer chain. The amide groups could form amide-amide hydrogen bonds to engender the twist of dihedral angle and the strong steric repulsion of phenol groups might have the opposite effect on the helix. The helical structure of the optically active polymers were conclusively constructed and stabilized by the optimization of intra- and intermolecular hydrogen bonding and steric repulsion of the side chains. Moreover, the infrared emissivity values of LPT and DPT at 30 °C were 0.682 and 0.671, which were much lower than RPT. LPT and DPT also showed superior heat resistance due to their unique helical conformation. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44824.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Hao Chen,Xiaofeng Xie,Chaofang Li,Xudong Liu,Fenghua Shen,Pingshan Wang,Kaisong Xiang,Hui Liu
Ionic liquids (ILs) show promise for flue gas purification, but suffer from the insufficient oxidation ability for elemental mercury (Hg 0 ) removal. In light of the critical role of electrophilic structure in the oxidation process, we proposed a novel strategy to enhance Hg 0 oxidative capture by steering electrophilicity of positively charged N center in the cation of IL. We screened ILs containing cations with N centers featuring varied hybridization and localization, and thioacetate anions that aid in immobilizing the resulting mercury ions. The electrophilicity of ILs, as determined by quantum chemical calculations, adheres to the following hierarchy: [Bpy][ThAc] (highly delocalized sp 2 -hybridized N) > [Bmim][ThAc] (low delocalized sp 2 -hybridized N) > [Bpyrr][ThAc] (sp 3 -hybridized N) ≈ [Bpip][ThAc] (sp 3 -hybridized N). This hierarchy correlated positively with experimental oxidation activity and Hg 0 removal performance. Specifically, the Hg 0 adsorption capacity of [Bpy][ThAc] (23.0 mg/g) was 3.6 times larger than that of [Bmim][ThAc]. Hg-TPD, XPS, and theoretical calculations corroborated that the highly delocalized sp 2 -hybridized N with a stable π system in [Bpy][ThAc] constitutes a strong electrophilic center, boosting electron transfer from Hg 0 to the cation. Subsequently, the oxidized Hg 2+ was immobilized through coordination with the anion. Furthermore, beyond the specific mercury removal process, the integration of Hg 0 capture with desulfurization was successfully achieved by introducing [Bpy][ThAc] into the IL employed for desulfurization, highlighting its adaptability and practicability. This work not only develops an effective remediator for Hg 0 removal from the flue gas but also offers design guidelines for ILs used in the oxidative degradation of other contaminants.
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