JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2017
·Vol. 55
·期 13
·2211-2220
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IF 2.952
Yuchen Feng,Suyun Jie,Bo-Geng Li
Fatty acid-derived cyclooctenes, including n -hexanoic acid ( M1 ), n -octanoic acid ( M2 ), lauric acid ( M3 ), and palmitic acid ( M4 ), were prepared as monomers and polymerized by ring-opening metathesis polymerization (ROMP) using Grubbs second-generation catalyst ( G2 ). In all the cases, the regio-irregular unsaturated polymers with pendent linear branches were obtained, which could be saturated by chemical hydrogenation with TSH/TPA in high conversion, yielding ethylene/vinyl ester copolymers with pendent linear branches on precisely every eighth backbone carbon. Both unsaturated and saturated polymers were amorphous, and their structures were characterized by FTIR, 1 H and 13 C NMR spectra, and elemental analysis. Differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) were used to study their thermal properties. The chain length of branches greatly affected the thermal properties of polymers. After hydrogenation, the thermal degradation stability of polymers was relatively improved. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2211–2220
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高影响因子
CHEMISTRY OF MATERIALS
·
2017
·
IF 9.466
Aifei Wang,Yanyan Guo,Faheem Muhammad,Zhengtao Deng
Hollow nanocrystals have attracted considerable attention in many areas of materials science because of their unique geometry, large surface area, high loading capacity and low density, and potential applications in catalysis, energy storage, drug delivery, and molecular separation. So far, numerous hollow nanostructured materials, such as noble metals, metallic oxides, hydroxides, and chalcogenides, have been reported. However, there is no report about the hollow metal halide perovskite nanocrystals yet. Herein, for the first time, we report the controlled synthesis of metal halide perovskite hollow nanocrystals, i.e., CsSnBr3 cubic nanocages, through a facile hot-injection colloidal approach. The formation of nanocages was controlled by rationally choosing the precursors and reaction temperature and was achieved through the self-assembly driven process. The as-synthesized CsSnBr3 nanocages exhibit excellent oxygen resistibility under desiccation conditions. Furthermore, treatment of CsSnBr3 nanocages with perfluorooctanoic acid results in an improved stability against moisture, oxygen, and light. This work represents a step toward hollow nanocrystals of metal halide perovskites for optical, electronic, and optoelectronic applications.
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Journal of the Taiwan Institute of Chemical Engineers
·
2016
·
IF 2.848
Ling Qin,Zhiping Zhou,Jiangdong Dai,Ping Ma,Haibin Zhao,Jinsong He,Atian Xie,Chunxiang Li,Yongshen Yan
In this research, shrimp shell, as an abundant, environmental-friendly and renewable biomass source, was successfully converted into novel N-doped hierarchically porous carbons (N-HPCs) via a simple self-template carbonization and KOH activation. The physical–chemical properties of N-HPCs were characterized by FT-IR, SEM, TEM, Raman, BET and elemental analysis. The optimum N-HPCs (named N-HPC-850-2) exhibited the highest specific surface area (3171 m 2 /g) and total pore volume (1.934 cm 3 /g), and was used to effectively eliminate sulfamethazine (SMZ) and chloramphenicol (CAP) from water. Batch adsorption results showed increasing temperature was in favor of adsorption and the N-HPC-850-2 had a high adsorption affinity toward two antibiotics over a broad pH range. Adsorption isotherm data were fitted with Langmuir model very well, with the maximum monolayer adsorption capacity of 699.3 and 742.4 mg/g for SMZ and CAP at 318 K, respectively. The pseudo-second-order rate model described adsorption kinetics data well and adsorption processes were governed predominately by intra-particle diffusion and film diffusion. The thermodynamic parameters indicated the spontaneous and endothermic adsorption. Importantly, the N-HPC-850-2 adsorbent also exhibited a good regeneration capacity. Here, we provided a promising approach to prepare low-cost and high-performance biomass-based N-HPCs for fast and highly efficient removal of antibiotics from aquatic system.
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ENERGY AND BUILDINGS
·
2017
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IF 4.067
Zhao Wang,Guixiang Ma,Shang Liu,Yan Jing,Jinhe Sun,Yongzhong Jia
The thermal properties of caprylic acid, nonanoic acid and their binary system were investigated by differential scanning calorimetry (DSC). The phase diagram for the binary system was constructed, and the experiment results showed that the eutectic temperature and the molar fraction of caprylic acid for the eutectic mixture are 1.83 °C and 0.483, respectively. To satisfy the application demands of the temperature scope from 5 °C to 15 °C, another binary mixture for the binary system with a molar fraction of 0.814 for caprylic acid component is found successfully, and it has good thermal properties that the melting temperature and the latent heat are 7.6 °C and 123 J g −1 , respectively. What is more, the latent heat and melting temperature for the binary mixture do not change at all nearly after being cycled 100 times during the whole melting process. As a novel phase change material (PCM) for application in the field of air conditioning and cooling, the binary mixture has own unique thermal advantages.
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高影响因子
JOURNAL OF LIQUID CHROMATOGRAPHY & RELATED TECHNOLOGIES
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2015
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IF 0.606
Peijin Wang,Xiaoyan Qiu,Yaling Yang
A novel vortex-assisted dispersive liquid–liquid microextraction method based on floating organic acid (VA-DLLME-FOA) droplet combined with high-performance liquid chromatography-fluorescence detection was successfully developed for extraction and preconcentration of three estrogens (estriol (E3), 17β-estradiol (βE2), and estrone (E1)) in human urine. In this method, estrogens were extracted into fine droplets of nonanoic acid, which floated on the top of the sample solution. Vortex-mix instead of organic dispersive solvent was applied to assist the dispersion of the extraction solvent into aqueous samples; due to the elimination of dispersive solvent, high extraction efficiency and enrichment factor could be achieved. Factors affecting VA-DLLME-FOA (type and volume of the extraction solvent, sample pH, vortex-mix time, and centrifugation) were optimized. The relative standard deviations (RSD%, n = 5) were 1.56–2.98% and the limits of detection were 0.01 ng mL−1 for E3, 0.01 ng mL−1 for βE2, and 0.06 ng mL−1 for E1. Recoveries of the estrogens in spiked human urine samples were in the range of 96.8–102.3%. The results showed that VA-DLLME-FOA was a simple, sensitive, low-cost, minimum organic solvent consumption and efficient analytical method for the separation and determination of estrogens in human urine samples.
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Analytical Methods
·
2013
·Vol. 5
·期 19
·5037-5043
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IF 1.855
Yingtang Li,Yang Jiao,Yuhong Guo,Yaling Yang
A new and fast microextraction technique termed vortex-assisted supramolecular solvent microextraction (VASUSME) has been developed. The method was based on the microextraction of endocrine disrupting compounds (EDCs), including bisphenol-A (BPA), 2,4-dichlorophenol (2,4-DCP), bisphenol-AF (BPAF) and tetrabromobisphenol-A (TBBPA) in 10 mL sample with 500 μL of a supramolecular solvent (SUPRASs), and then detection by high-performance liquid chromatography (HPLC). In the VASUSME procedure, dispersion of microvolumes of a low density extraction solvent into the aqueous sample is achieved by vortex mixing, a mild emulsification procedure. Under the optimum conditions, the repeatability of the proposed method was found to be good. The relative standard deviations (RSD, n = 5) were 3.98–5.64%. The limits of detection (LOD) were in the range of 0.14–0.32 ng mL−1 and the limits of quantification (LOQ) were in the range of 0.41–1.02 ng mL−1. All correlation coefficients of the calibration curves were higher than 0.998. Recoveries of the EDCs spiked into samples of liquid foods and their packaging materials were in the range of 91% to 105.1%. The VASSUSME method was successfully applied to the analysis of BPA, 2,4-DCP, BPAF and TBBPA in samples of liquid foods and their packaging materials. Moreover, the method is simple, sensitive and environmentally-friendly and consumes much less solvent than traditional methods.
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RSC Advances
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2014
·Vol. 4
·期 67
·35620-35628
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IF 3.708
Yanxiong Pan,Chao Peng,Weicai Wang,Kai Shi,Zhi Liu,Xiangling Ji
A series of macroporous hydrophobic polyvinyl alcohol–formaldehyde sponges (PVF–Gn–Hms) are prepared via the reactions of hydrophilic polyvinyl alcohol–formaldehyde (PVF) sponges with glutaraldehyde (GA) and fatty acyl chloride. Both ATR-IR and solid-state CP/MAS 13C-NMR spectra confirm a successful substitution of alkyl chain on PVF sponges, and the calculated degree of substitution (DS) is in the range of 32.3–62.3%. PVF–Gn–Hms sponges have similar apparent densities as the pristine PVF sponges and exhibit a unimodal macropore size distribution with a peak centered at about 60 μm and a high porosity of 90%. PVF–Gn–Hms maintain the original open-cell structure well, and their surface hydrophobicity effectively increases with the n-alkyl chain length and reaction temperature. The effect of preparation conditions, including the feed ratio of crosslinker glutaraldehyde to OH groups ([GA]/[OH] = 0–4), alkyl chain length of fatty acyl chloride, reaction temperature and apparent density of pristine PVFs, on absorption behavior to organic pollutants is investigated extensively. Fourteen common solvents with solubility parameters from 7.24 to 13.40 cal1/2 cm−3/2 are selected as organic pollutants. Results demonstrate that the resultant PVF–Gn–Hms with a higher feed ratio of [GA]/[OH] (from 0 to 4) possess lower absorption capacities in most organic solvents because of a relatively higher crosslinking degree. The sponges prepared at higher reaction temperatures only exhibit slightly increased absorption capacities, and a relatively lower apparent density of pristine hydrophilic PVF facilitates higher absorption capacities. Definitely, the hydrophobic sponges with different apparent densities exhibit excellent reusability and recovery (up to 93.0%) during 35 successive absorption–squeezing cycles and excellent absorption selectivity in the water-organic solvent mixture experiment. More importantly, as-prepared sponges possess hydrophobic surfaces, open-cell structures, high porosity, as well as excellent reusability and selectivity, which make them ideal candidates as absorbents for organic pollutants.
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FOOD CHEMISTRY
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2014
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IF 3.259
Peijin Wang,Yu Xiao,Wenjun Liu,Juan Wang,Yaling Yang
A rapid, simple, sensitive and environmentally friendly method has been developed for the determination of three oestrogens (17β-estradiol (17β-E2), estrone (E1), and diethylstilbestrol (DES)) in milk samples by using vortex-assisted hollow fibre liquid-phase microextraction (VA-HF-LPME) and high performance liquid chromatography. Method is based on the microextraction of oestrogens from sample solution into 15 μL of nonanoic acid as extracting agent, which is placed inside the hollow fibre followed by vortex-mixing. Vortex provided effective and mild mixing of sample solution and increased the contact between analytes and boundary layers of the hollow fibre, thereby enhancing mass transfer rate and leading to high recovery of target analytes. The extraction equilibrium is achieved within 2 min. Parameters influencing the recovery were investigated and optimized. The proposed technique provided good linearity (>0.9984), repeatability (RSD = 2.56–4.38), low limits of detection (0.06–0.17 ng mL −1 ), and high enrichment factor (330).
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PubMed
高影响因子
CATALYSIS COMMUNICATIONS
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2013
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IF 2.915
Hong-De Yan,Qun Zhang,Zhao Wang
A lipase from Aspergillus oryzae WZ007 exhibited high esterification activities toward a series of short-chain acids and alcohols. Moreover, it displayed a strong tolerance for high substrate concentration of up to 2.0 M and presented a highest initial rate of 276 mmol·L − 1 ·h − 1 at this concentration. After a reaction time of 48 h, the conversion rates of acids were higher than 80% for the synthesis of a majority of heptanoic acid esters, some octanoic acid esters and n -propyl hexanoate. These results implied that A. oryzae WZ007 lipase was a promising biocatalyst in the production of flavor esters.
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CHEMISTRY-A EUROPEAN JOURNAL
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2015
·Vol. 21
·期 9
·3671-3681
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IF 5.731
Bin Wu,Keyang Chen,Yuchen Deng,Jian Chen,Chengjie Liu,Rongshi Cheng,Dongzhong Chen
Graphical Metalloporphyrin liquid crystals : Well-organized hexagonal columnar mesophases of broad temperature ranges have been achieved in metal complexes of easily available fatty acid octaester substituted porphyrins. The liquid crystallinity of the free base and the metal porphyrins can be tuned with variant length side-chain substituents and different coordinated metal ions (see figure; TPP=tetraphenyl porphyrin). A series of meta -substituted fatty acid octaester derivatives and their transition-metal complexes of meso - tetraphenyl porphyrins (TPP-8OOCR, with R=C n −1 H 2 n −1 , n =8, 12, or 16) have been prepared through very simple synthesis protocols. The thermotropic phase behavior and the liquid crystalline (LC) organization structures of the synthesized porphyrin derivatives were systematically investigated by a combination of differential scanning calorimetry (DSC), polarized optical microscopy (POM), and variable-temperature small-angle X-ray scattering/wide-angle X-ray scattering (SAXS/WAXS) techniques. The shorter octanoic acid ester substituted porphyrin (C8-TPP) did not show liquid crystallinity and its metal porphyrins exhibited an uncommon columnar mesophase. The lauric acid octaester (C12-TPP) and the palmitic acid octaester (C16-TPP) series porphyrins generated hexagonal columnar mesophase Col h . Moreover, the metal porphyrins C12-TPPM and C16-TPPM with M=Zn, Cu, or Ni, exhibited well-organized Col h mesophases of broad LC temperature ranges increasing in the order of TPPNi
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
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2015
·Vol. 16
·期 4
·7273-7288
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IF 2.862
Dongming Lan,Qian Wang,Jinxin Xu,Pengfei Zhou,Bo Yang,Yonghua Wang
Thermostability and substrate specificity are important characteristics of enzymes for industrial application, which can be improved by protein engineering. SMG1 lipase fromMalassezia globosais a mono- and diacylglycerol lipase (MDL) that shows activity toward mono- and diacylglycerols, but no activity toward triacylglycerols. SMG1 lipase is considered a potential biocatalyst applied in oil/fat modification and its crystal structure revealed that an interesting residue-Asn277 may contribute to stabilize loop 273–278 and the 3104 helix which are important to enzyme characterization. In this study, to explore its role in affecting the stability and catalytic activity, mutagenesis of N277 with Asp (D), Val (V), Leu (L) and Phe (F) was conducted. Circular dichroism (CD) spectral analysis and half-life measurement showed that the N277D mutant has better thermostability. The melting temperature and half-life of the N277D mutant were 56.6 °C and 187 min, respectively, while that was 54.6 °C and 121 min for SMG1 wild type (WT). Biochemical characterization of SMG1 mutants were carried out to test whether catalytic properties were affected by mutagenesis. N277D had similar enzymatic properties as SMG1 WT, but N277F showed a different substrate selectivity profile as compared to other SMG1 mutants. Analysis of the SMG1 3D model suggested that N277D formed a salt bridge via its negative charged carboxyl group with a positively charged guanidino group of R227, which might contribute to confer N277D higher temperature stability. These findings not only provide some clues to understand the molecular basis of the lipase structure/function relationship but also lay the framework for engineering suitable MDL lipases for industrial applications.Keywords:mono- and diacylglycerol lipase;thermostability;substrate selectivity;site-directed mutagenesis
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PubMed
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INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2017
·Vol. 41
·期 15
·2555-2564
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IF 2.598
Zhao Wang,Shang Liu,Guixiang Ma,Shaolei Xie,Guangwei Du,Jinhe Sun,Yongzhong Jia
Summary To satisfy the application demands for latent heat storage in the temperature range from 5°C to 15°C, an original composite phase change material (PCM), CA-NA/EG (caprylic-nonanoic acid/expanded graphite), was prepared and characterized. For CA-NA/EG, the mass ratio of CA and NA was 8:2, and the mass percentage of the CA-NA in CA-NA/EG composite PCM was determined as 90% by leakage test. The melting and freezing points of the CA-NA/EG were 6.84°C and 9.34°C, and corresponding latent heats were 108.75 kJ/kg and 107.67 kJ/kg. In addition, its thermal conductivity, thermal stability and reliability were investigated by thermal conductivity apparatus (TCA), thermal gravimetric analyzer (TGA), and accelerated thermal cycle test for 100 melt/freeze cycles, respectively. The results showed that the CA-NA/EG had a good thermal stability and an excellent thermal reliability. Moreover, the thermal conductivity of CA-NA/EG had an improvement of 25% than that of the CA-NA. On the other hand, the accelerated thermal cycle test also indicated that the CA-NA/EG had no supercooling during all melt/freeze cycles. Therefore, the prepared composite PCM, CA-NA/EG, can be applied for low-temperature thermal energy storage owing to its proper melting temperature, acceptable latent heat and thermal conductivity, excellent thermal stability and reliability.
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危险品化学品经营许可证（带存储）