EUROPEAN POLYMER JOURNAL
·
2020
·
IF 3.862
Qingqing Ye,Baozhong Zhang,Yanhua Yang,Xiaoyu Hu,Yingzhong Shen
Two different aromatic diamines monomers (3, 5-diamino-N-(4'-phenyl-4''-triphenylamino)-N-(4''-benzyl-4'''-triphenylamino)benzamide (DPTBTB) and 3, 5-diamino-N-(4'-3'', 4'', 5''-trifluorobiphenyl)-N-(4''-benzyl-3''', 4''', 5'''-trifluorophenyl)benzamide (DTBTB)) containing flexible linkages were designed and synthesized, respectively. Four organo-solubility polyimides (PI-a, PI-b, PI-c, and PI-d) were prepared via a two-step procedure with pyromellitic dianhydride (PMDA) and 3, 3', 4, 4'-biphenyltetracarboxylic dianhydride (BPDA), respectively. The four PIs performed excellent thermal stability with the temperature of 5% weight loss in range of 370–420 ℃ at N 2 atmosphere. The Al/PI-a/ITO and Al/PI-b/ITO memory devices exhibited binary write-once-many-read (WORM) and rewritable (Flash) behavior, respectively. But the Al/PI-c/ITO and Al/PI-d/ITO memory devices showed ternary WORM and Flash behavior due to the deeper charge traps came from the fluorinated groups in the structure of PI-c and PI-d, respectively. The memory switching mechanism could be demonstrated through molecular simulation. The results gave an effective strategy that adjusting the structure of PI to achieve different memory effects.
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高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2018
·
IF 2.631
Sheng Zhang,Xiaxia Song,Guowei Lin,Qi Yang,Quan Shi,Hui Zheng,Xin Liu,Qing Wei,Gang Xie,Sanping Chen,Shengli Gao
In this paper, two new H 2 ZTO-Co(II) coordination polymers (H 2 ZTO = 4,4′-azo-1,2,4-triazol-5-one), [Co(H 2 ZTO) 2 (H 2 O) 4 ](NO 3 ) 2 (1) and {[Co(H 2 ZTO)(H 2 O) 4 ](NO 3 ) 2 ·2H 2 O} n (2), have been synthesized and characterized. Polymer 2 is derived from 1 and undergoes a multistage transformation by soaking 1 in distilled water. X-ray single crystal structure analyses showed that 2 exhibit a one-dimensional (1D) chain geometry coordinated by 0D units of 1 through uncoordinated nitrogen atoms of H 2 ZTO ligands. The thermal decomposition behaviors and magnetic properties of 1 and 2 were discussed. In addition, the low-temperature (1.9–300 K) heat capacities of 1 and 2 were measured using the heat capacity option of a Quantum Design Physical Property Measurement System (PPMS). The thermodynamic functions of 1 in the experimental temperature range were derived by fitting the heat capacity data to a series of theoretical and empirical models. Using the fitted heat capacity results, the standard molar entropy and standard molar enthalpy have been respectively calculated to be (871.1 ± 8.7) J·mol −1 ·K −1 and (132.7 ± 1.3) kJ·mol −1 for 1 .
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JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
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2018
·
IF 2.891
Huili Zhang,Zhiyuan Feng,Yekun Zhu,Ying Wu,Tinghua Wu
WO 3 /g-C 3 N 4 (graphitic carbon nitride) composite was prepared via a directly calcination method with ammonium tungstate hydrate and melamine as raw materials, and applied in the photocatalytic oxidation of 5-hydroxymethylfurfural (5-HMF) to 2,5-diformylfuran (DFF) for the first time. Its physicochemical properties were characterized by HR(TEM), XRD, FT-IR, XP, UV-vis, PL, PC and EIS methods. The results revealed that the doping of WO 3 into g-C 3 N 4 can reduce the possibility of charge recombination and thus enhancing the photocatalytic activity. The impact factor, such as incident wavelength, reaction time, and solvent were also studied on the photocatalytic behavior. 4.7%WO 3 /g-C 3 N 4 composite catalyst exhibits the highest 5-HMF conversion of 27.4% with DFF selectivity of 87.2% under the irradiation of visible-light (>400 nm). As the active species, O 2 − and h + plays an important role to convert 5-HMF to DFF. Finally, the Z-scheme mechanism and reaction route were proposed by combining the photocatalytic performance with the active oxygen species research of the WO 3 /g-C 3 N 4 catalyst.
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高影响因子
FIBERS AND POLYMERS
·
2018
·Vol. 19
·期 7
·1363-1372
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IF 1.353
Fu Yifan,Teng Yun,Yu Guomin,Yin Cuiyu
Unmodified polyamide 6 commonly dyed with acid dyes, and has no flame-retarded properties. So they are flammable and can be easily stained by foods or drinks that contain acid dyes. However, the acid groups react with amino groups that existed at the end of PA6 chain while using cationic dyes. Thus, the acid dyes can be washed immediately. In this study, the flame retardant and cationic dyeable polyamide 6 (FRCD-PA6) modified with 5-sulfoisophthalic acid sodium (5-SSIPA) and melamine cyanurate (MCA) was successfully prepared by the two-step-melt polymerization method. Firstly, cationic dyeable polyamide 6 (CD-PA6) was prepared with sodium salt from 5-sulfoisphthalic acid. Secondly, melamine cyanurate, as an efficient flame retardant, was blended into the reaction. The chemical and crystalline structures of FRCDPA6 were characterized by the Fourier transform infrared spectroscopy (FT-IR) and wide angle X-ray diffraction (XRD). Their thermal properties were tested by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and morphology was analyzed by SEM, respectively. It had been measured to prove the dispersion of 5-SSIPA and MCA on polyamide 6 matrix. Incorporating with 5-SSIPA created more amorphous regions and rose up the dyeing rate easily, with a highest dyeing rate for about 96.79 %. The effect of varying MCA content on the composites showed more flame retardant and made better heat-resistance. Moreover, with the appropriate addition of MCA content, the limit oxygen index (LOI) reached up to 27, less smoking, no more black smoke, droplet phenomenon was slightly, and flame resistance had greatly improved. Because of the good synergy between 5-SSIPA and MCA, a kind of novel modified polyamide 6 which own both cationic dyeable and efficient flame retardant properties was born.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2018
·
IF 2.196
Yongzhao Zhang,Xia Guo,Jian Xu,Yuxiang Wu,Meizhen Lu
Liquid–liquid equilibrium (LLE) data was very important for the process design and optimization of 5-hydroxymethylfurfural (5-HMF) production. To provide this fundamental data, experimental liquid–liquid equilibrium data for ternary systems, {water + 5-HMF + 1-butanol}, {water + 5-HMF + isobutanol}, and {water + 5-HMF + methyl isobutyl ketone}, were measured at 313.15, 323.15, and 333.15 K. Partition coefficients were used to assess the extraction capacity of organic solvents in the biphasic systems. 1-Butanol and isobutanol were desirable extractants with good extraction performance and environmental benign properties. The NRTL model was used to correlate the experimental data and the binary interaction parameters were obtained. The average relative deviation was lower than 10%.
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Journal of Zhejiang University-SCIENCE B
·
2018
·
IF 1.815
Zhu Chen,Shang Deng,De-chao Yuan,Kang Liu,Xiao-cong Xiang,Liang Cheng,Dong-qin Xiao,Li Deng,Gang Feng
Objective: To construct a novel non-viral vector loaded with growth and differentiation factor-5 (GDF-5) plasmid using chitosan, hyaluronic acid, and chondroitin sulfate for osteoarthritis (OA) gene therapy. Methods: Nano-microspheres (NMPs) were prepared by mixing chitosan, hyaluronic acid, and chondroitin sulfate. GDF-5 plasmid was encapsulated in the NMPs through electrostatic adsorption. The basic characteristics of the NMPs were observed, and then they were co-cultured with chondrocytes to observe their effects on extracellular matrix (ECM) protein expression. Finally, NMPs loaded with GDF-5 were injected into the articular cavities of rabbits to observe their therapeutic effects on OA in vivo. Results: NMPs exhibited good physicochemical properties and low cytotoxicity. Their average diameter was (0.61±0.20) μm, and encapsulation efficiency was (38.19±0.36)%. According to Cell Counting Kit-8 (CCK-8) assay, relative cell viability was 75%–99% when the total weight of NMPs was less than 560 μg. Transfection efficiency was (62.0±2.1)% in a liposome group, and (60.0±1.8)% in the NMP group. There was no significant difference between the two groups ( P >0.05). Immunohistochemical staining results suggested that NMPs can successfully transfect chondrocytes and stimulate ECM protein expression in vitro. Compared with the control groups, the NMP group significantly promoted the expression of chondrocyte ECM in vivo ( P <0.05), as shown by analysis of the biochemical composition of chondrocyte ECM. When NMPs were injected into OA model rabbits, the expression of ECM proteins in chondrocytes was significantly promoted and the progression of OA was slowed down. Conclusions: Based on these data, we think that these NMPs with excellent physicochemical and biological properties could be promising non-viral vectors for OA gene therapy.
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PubMed
高影响因子
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
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2018
·Vol. 2019
·期 1
·51-58
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IF 2.507
Hangle Guo,Tongguang Ge,Jian Lv,Changlin Du,Jian Zhou,Zhicheng Liu,Zile Hua
Graphical A facile and eco-friendly mesoporogen-free steam-assisted crystallization strategy has been developed for the synthesis of hierarchically structured ZSM-5 zeolites with superior MTP catalytic performance, and a new “in situ alkali etching-hydrothermal restoring“ mechanism is discussed. A series of hierarchically structured ZSM-5 zeolites (ZSM-5 HSZs) with a Si/Al ratio of about 200 have been successfully synthesized in the absence of additional mesoporous agents. XRD, N 2 sorption isotherms, SEM, TEM and NH 3 -TPD results showed that the obtained HSZs materials possess high crystallinity, interconnected micro/mesoporous structures and similar total acid amounts. Meanwhile, in the methanol-to-propylene (MTP) reaction, compared to the microporous counterpart, all synthesized ZSM-5 HSZs demonstrated superior performance benefitting from their hierarchical porous structures. Interestingly, 27 Al MAS NMR and Py-FTIR results confirmed the inter-transformation of framework and extra-framework Al species with the extension of materials crystallization duration and consequently the variation of materials surface acidity. As a result, the optimized catalyst achieved the highest initial propylene selectivity of 54.4 % and the longest catalyst lifetime ( t 90 ) of 175 h under the weight hourly space velocity (WHSV) of 1.0 g g –1 h –1 . Moreover, a new “in situ alkali etching-hydrothermal restoring“ mechanism has been proposed to elucidate the structural evolution of here reported high-silica ZSM-5 HSZs during the synthesis.
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高影响因子
NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 22
·18084-18095
·
IF 3.201
Kai Wang,Yunlei Zhang,Jiaojiao Zhao,Changhao Yan,Yanan Wei,Minjia Meng,Xiaohui Dai,Chunxiang Li,Yongsheng Yan
Herein, rod-shaped modified halloysite nanotubes (m-HNTs) with suitable wettability and basic active sites were utilized as stable particles to stabilize W/O Pickering HIPEs. Immediately following the thermal polymerization treatment and the subsequent sulfonation process, we have synthesized hierarchical porous solid catalysts (HPSCs) with acid–base bifunctional active sites. The as-prepared HPSCs have hierarchical meso–macroporous structures, strongly acidic surfaces and basic catalytic active sites, which can remarkably improve the catalytic activity for the conversion of cellulose to 5-hydroxymethylfurfural (HMF). This suggests that the stable particles with basic active sites embedded in the porous structure of HPSCs can significantly improve the catalytic activity. The results showed that a maximum yield of HMF (45.6%) can be obtained and the catalyst was recycled in four consecutive cycles without significant loss of catalytic activity. Moreover, this provides a new way for the development of multistage pore structure catalysts for catalytic conversion of carbohydrates.
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JOURNAL OF CATALYSIS
·
2018
·
IF 6.759
Tianyu Gao,Jing Chen,Wenhao Fang,Qiue Cao,Weiping Su,Franck Dumeignil
Mn-Ce mixed oxides-supported Ru nanoparticles (Ru/Mn X Ce 1 O Y ) with enhanced oxygen mobility and strong metal-support interaction were prepared and applied to the aerobic oxidation of 5 -hydroxymethylfurfural (HMF) to 2,5 -furandicarboxylic acid (FDCA) without addition of any base additives. Oxygen and water were used as green oxidant and solvent, respectively. The catalysts were characterized in depth by XRD, H 2 -TPR, O 2 -TPD, UV–Vis DRS, XPS and TEM, to reveal materials properties from bulk to surface. The influence of Mn/Ce molar ratios in support materials and reaction parameters ( i.e. , HMF/Ru ratio, O 2 pressure, reaction temperature and time) was systematically studied and optimized. The reaction route and rate-determining step for oxidation of HMF to FDCA over the Ru/Mn X Ce 1 O Y catalysts were investigated by kinetic analysis. Well-dispersed metallic Ru nanoparticles with a mean size of 4.4 nm deposited on the support were found essential to activate and oxidize the HMF molecule. The Mn/Ce molar ratio was found to affect not only conversion of HMF but also distribution of products. The Ru/Mn 6 Ce 1 O Y catalyst demonstrated an exceptional yield (≥99%) of FDCA, which corresponds in our conditions to one of the best productivity (5.3 mol FDCA ·mol Ru −1 ·h −1 ) ever reported in literature. The superior activity of the Ru/Mn 6 Ce 1 O Y catalyst was mainly associated with (i) the strong metal-support interaction and (ii) the synergistic effect between manganese and cerium oxides. This catalyst showed the highest surface concentrations in Mn 4+ and Ce 3+ among the series, which, as a consequence, enhanced the availability and mobility of active oxygen species. This catalyst was shown resistant to deactivation during eight recycling uses thanks to a strong metal-support interaction between Ru nanoparticles and the Mn-Ce mixed oxide used as a support.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Hui-Fang Ye,Rui Shi,Xiao Yang,Wen-Fu Fu,Yong Chen
Photocatalytic water splitting over semiconductors without using of any electron sacrificial agents is essential to the conversion of solar energy into chemical energy. Herein, we report remarkable photocatalytic hydrogen production from pure water without the assistance of electron sacrificial agents by using P-doped Zn x Cd 1−x S with rich S vacancies (Zn x Cd 1−x S-P) as the photocatalyst. It is found that interstitial P doping in Zn x Cd 1−x S solid solutions with rich S vacancies can prolong the lifetime of charge carriers and enhance the generation and separation of photogenerated electrons-holes, resulting in a H 2 evolution rate of up to 419 μmol h −1 g −1 , which is 72 and 7.5 times higher than those of ZnS-P (5.8 μmol h −1 g −1 ) and CdS-P (56 μmol h −1 g −1 ), respectively. Furthermore, the introduction of biomass-derived compound 5-hydroxymethylfurfural (HMF) into this system further promotes the photocatalytic hydorgen evolution reaction and simultaneously obtains value-added HMF oxidation products.
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RSC Advances
·
2015
·Vol. 5
·期 75
·60736-60744
·
IF 3.84
Yanfang Wang,Zhen Gu,Wentao Liu,Yuan Yao,Haijun Wang,Xiao-Feng Xia,Wei Li
A series of novel catalysts were prepared by immobilizing chromium(III) Schiff base complexes and acidic ionic liquids onto the surface of MCM-41, and characterized by FT-IR, TG, XRD, SEM, TEM, NH3-TPD, ICP-OES and N2 sorption studies. The catalytic activity of the prepared solid catalysts was investigated for the conversion of biomass (mainly including glucose, fructose and inulin) in the presence of DMSO. The dependencies of catalytic activity on reaction parameters such as temperature, reaction time and solvent were investigated and the reaction conditions were optimized. A HMF yield of 43.5% was achieved from glucose using Cr(salen)-IM-HSO4-MCM-41 as the catalyst in DMSO at 140 °C for 4 h. Furthermore, the catalyst also demonstrated good activity, and as high as 83.5% HMF was directly obtained from fructose, and the HMF yield reached 80.2% when inulin was selected as the substrate. The immobilized catalysts developed in this study present improved performance over other solid catalysts, and they have been efficiently and easily recycled at least five times without significant loss of activity in glucose conversion and HMF yield.
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GREEN CHEMISTRY
·
2015
·Vol. 17
·期 8
·4206-4216
·
IF 8.02
Jinxia Zhou,Zhi Xia,Tingyu Huang,Peifang Yan,Wenjuan Xu,Zhanwei Xu,Jianji Wang,Z. Conrad Zhang
Increasing the glucose loading in the 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid containing a dissolved CrCl3 catalyst system led to excessive formation of humins and a serious decrease in the 5-hydroxymethylfurfural (5-HMF) yield. A biphasic system containing glycol dimethyl ether (GDE) as the extraction phase, and [BMIM]Cl/CrCl3/glucose in combination with a partitioned amount of GDE and an appropriate amount of water as the reaction phase was found to be highly efficient for the reaction; CrCl3 catalyzed the formation of 5-HMF in 64.5 mol% yield from a very high glucose concentration (80 wt% with respect to the ionic liquid) at 108 °C. This 5-HMF yield in the [BMIM]Cl–GDE–H2O ternary biphasic system nearly doubled that obtained in the single [BMIM]Cl/CrCl3/glucose reaction phase. Importantly, the GDE phase contained about 56% of the generated 5-HMF without detectable contamination by the ionic liquid or carbohydrates. GDE served multiple functions: as a hydrogen-bond acceptor, it exhibited excellent extraction performance for 5-HMF; due to its low boiling point and suitable solubility saturation point in the ionic liquid, a sustained GDE bubbling phenomenon in the ionic liquid phase was observed that promoted the rate of inter-phase mass-transfer of 5-HMF in reactions; and GDE mediated the [BMIM]Cl phase to a reduced viscosity. In addition, an appropriate amount of water in the ternary system promoted the extraction efficiency of 5-HMF and also lowered the viscosity of [BMIM]Cl/glucose. The ionic liquid–organics–water ternary biphasic system has been demonstrated for high 5-HMF productivity and separation efficiency.
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危险品化学品经营许可证（带存储）