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01 April 2015, Volume 31 Issue 2

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Chemical Research in Chinese Universities Vol.31 No.2 February 2015

2015, 31(2):  0-0. 

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Letters

Cu-Catalyzed Aryl C―H Halogenation Using N-Halosuccinimides via Assistance of Benzoic Acid

DU Zhijun, GAO Lianxun, LIN Yingjie

2015, 31(2):  167-170.  doi:10.1007/s40242-015-4512-9

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Fabrication of Metallic Crescent-shaped Nanohole Arrays by Combination of Nanoimprint Lithography and Nanotransfer Printing

GAO Liguo, WU Feifei, TENG Fei, FENG Lei, LÜ Nan

2015, 31(2):  171-174.  doi:10.1007/s40242-015-4442-6

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Articles

Rapid Microwave-assisted Hydrothermal Synthesis of SrWO₄:Eu³⁺ Nanowires and Their Luminescence Properties

LÜ Yang, YANG Min, YANG Bin, LIU Wei, ZHANG Hongdan, ZHAO Xudong, LIU Xiaoyang

2015, 31(2):  175-178.  doi:10.1007/s40242-015-4448-0

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SrWO₄:Eu³⁺ nanowires were synthesized at 160 ℃ within 10 min via a microwave-assisted hydrothermal method. In examining the influences of synthesis temperature and reaction time on the morphology of nanowires, it was found that any temperatures and reaction time except 160 ℃ and 10 min gave rise to poorer morphologies under otherwise equal conditions. The synthesized nanowires were characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), high-resolution transmission electron microscopy(HRTEM), energy dispersive X-ray(EDX) and Raman spectrometry, respectively. The results suggest that the samples are homogenous and dispersive single phase nanowires. The photoluminescence properties of the nanowires were determined with a spectrofluorometer. Two obviously sharp peaks at 395 and 464 nm and a broad peak centered at 290 nm were found in their excitation spectrum. Under excitation at 395 and 464 nm , the ⁵D₀→⁷F₂ transition is the dominant process which means Eu³⁺ ion is located at a low symmetry site, while the ⁵D₀→⁷F₁ transition dominates under the excitation at 290 nm, showing a highly symmetric field around the Eu³⁺ ion, which indicates the presence of the two local Eu³⁺ environments.



Two New Supramolecular Hybrids Based on Bi-capped Keggin {PMo₁₂V₂O₄₂} Clusters and Transition Metal Mixed-organic-ligand Complexes

DUAN Weijie, JIAO Shihui, LIU Xu, CHEN Jinlei, CAO Xuan, CHEN Yan, XU Wei, CUI Xiaobing, XU Jiqing, PANG Guangsheng

2015, 31(2):  179-186.  doi:10.1007/s40242-015-5033-2

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Two supramolecular compounds [Cu(imz)₂][Cu(phen)(imz)]₂{[Cu(phen)]₂[PMo₆^VIMo₆^VV₂^IVO₄₂]}(1) and [Co₂(2,2'-bpy)₄(C₂O₄)][Co(2,2'-bpy)₃][PMo₇^VIMo₅^VV₂^IVO₄₂](2,2'-bpy)_0.5·H₂O(2)(phen=1,10'-phenanthroline, imz= imidazole, 2,2'-bpy=2.2'-bipyridine) have been synthesized hydrothermally and characterized by elemental analyses, infrared spectrum, UV-Vis, X-ray photoelectron spectroscopy(XPS), electron spin resonance(ESR) spectra, thermogravimetry analyses and single crystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses revealed that both the compounds represent the examples of compounds based on the bi-capped Keggin polyoxoanion {PMo₁₂V₂O₄₂} and transition metal mixed-organic-ligand coordination complexes. Compound 1 consists of bi-capped Keggin polyoxoanion [PMo₁₂V₂O₄₂]^5- supported copper coordination groups, which are further inter- connected with two types of copper complex fragments forming a 3D supramolecular framework via π…π stacking, C—H…O and N—H…O hydrothermal bonding interactions. Compound 2 is a new hybrid consisted of polyoxoanion [PMo₁₂V₂O₄₂]^4-, [Co₂(2,2'-bpy)₄(C₂O₄)]²⁺ and [Co(2,2'-bpy)₃]²⁺. There are no direct interactions in compound 2, but the polyoxoanions together with two different cobalt complex groups construct a 3D supramolecular network through C—H…O hydrogen bonding interactions.



A Series of Lanthanide Coordination Polymers Constructed from 4-Pyridin-4-ylbenzoate

FANG Weihui, YANG Guoyu

2015, 31(2):  187-191.  doi:10.1007/s40242-015-4316-y

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Four lanthanide coordination polymers, LaL₃(H₂O)₂(1), LnL₂(μ₃-OH)(H₂O)[Ln=Eu(2),Tb(3)] and ErL₃·2H₂O(4) were synthesized via hydrothermal reactions of lanthanide oxide with 4-pyridin-4-ylbenzonic acid(HL), and characterized by means of elemental analyses, infrared(IR) spectrometer, powder X-ray diffraction(PXRD), thermogravimetric analyses(TGA) and single-crystal XRD. The results reveal that complex 1 possesses a linear chain structure, complexes 2 and 3 possess isostructural ladder-like chains, while complex 4 possesses a 2D layer with 4-connected sql topology. Furthermore, the luminescence properties and UV-Vis spectra of complexes 2 and 3 were investigated.



Predicting Chromatographic Retention Time of C₁₀-Chlorinated Paraffins in Gas Chromatography-Mass Spectrometry Using Quantitative Structure Retention Relationship

XIA Zhenzhen, CAI Wensheng, SHAO Xueguang

2015, 31(2):  192-197.  doi:10.1007/s40242-015-4366-1

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Chlorinated paraffins(CPs) are potential persistent organic pollutants(POPs), which threat the safety of environment and organisms. However, the analysis of CPs is a difficult task due to their complex composition containing thousands of congeners. In the present work, quantitative structure retention relationship(QSRR) of CPs was studied. A total of 470 molecular descriptors were generated, for describing the structures of 28 CPs and 12 descriptors relevant to retention time of the CPs were selected by stepwise regression. Then, QSRR models between retention time on the one hand and the selected descriptors on the other hand were established by multiple linear regression(MLR), partial least squares(PLS) and least square support vector regression(LS-SVR). The result shows that PLS model is better than MLR and LS-SVR, obtaining a squared correlation coefficient(r²) of 0.9996 and a root mean squared error(RMSE) of 0.015. The PLS model was then used to predict the retention time of 49 C₁₀-CPs. Three of them were investigated by gas chromatography coupled with mass spectrometry(GC-MS). A well-defined correlation was found between the measured retention time and the predicted value.



Noninvasive Surface Detection of Papillary Thyroid Carcinoma by Fourier Transform Infrared Spectroscopy

ZHANG Weitao, TIAN Peirong, ZHU Qing, ZHANG Yuanfu, CUI Long, XU Zhi

2015, 31(2):  198-202.  doi:10.1007/s40242-015-4354-5

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Previously Fourier transform infrared(FTIR) spectroscopy has been applied to detecting thyroid cancer during operations and to discriminating cervical metastatic ones from non-metastatic lymph nodes. This study explored the possibility of establishing a sensitive, accurate and noninvasive screen or diagnosis by preoperative FTIR spectroscopy. 111 patients undergone a thyroid operation and 50 healthy volunteers were enrolled in the study. The FTIR spectra were obtained by two mid-infrared optical fibers with an attenuated total reflectance(ATR) probe closely contacting the subjects' skin on the thyroid nodules. The FTIR spectra obtained from normal thyroid, nodular goiter(NG) and papillary thyroid carcinoma(PTC) patients were compared. A Fisher's discriminant analysis was created based on these data. There were 41 PTC patients and 70 NG patients according to their histopathological examinations. A total of 23(of 39) parameters were statistically different among the three groups(P<0.05). The F₁₃₀₀ and F₁₀₈₀ parameters were significantly different between the three groups. In total, 9 out of 39 FTIR parameters were selected as independent factors by the Wilks' lambda stepwise discriminant analysis. The discrimination accuracy of papillary thyroid carcinoma in the three groups was 88.8%. Surface detection of PTC by FTIR spectroscopy is feasible. FTIR spectroscopy can be used for rapid and noninvasive PTC screen and auxiliary diagnosis.



Efficient Synthesis of α-Amino Acid Derivatives via Phase-transfer-catalyzed Directed Reductive Amination

ZHANG Xiaohua, YE Wenjing, WANG Kuanglei, TIAN Yongshou, XIAO Xiao

2015, 31(2):  203-207.  doi:10.1007/s40242-015-4412-z

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An efficient phase-transfer-catalyzed directed reductive amination of α-keto esters was described using simple substituted benzyl amines as nitrogen source and K₂CO₃ as base at room temperature, giving a series of aliphatic α-amino acid derivatives in moderate to high yields(up to 99%). Preliminary study on this asymmetric process showed that cinchona-derived phase transfer catalyst was effective, affording the corresponding product in 13% e.e. and 40% yield.



One-pot Three-component Reaction for Efficient and Facile Synthesis of γ-Nitrocarbonyl Compounds Under Solvent-free Conditions

LÜ Chengwei, LIU Yanhang, ZHOU Xiaoxia, WANG Jiajing

2015, 31(2):  208-211.  doi:10.1007/s40242-015-4410-1

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A simple and efficient protocol was established to synthesize γ-nitrocarbonyl compounds via three-component one-pot tandem condensation reaction of aldehydes, Meldrum's acid and nitroalkanes under solvent- free conditions. The present method shows fascinating features such as using readily available starting materials, promoting the yields by inexpensive and mild organic base triethylamine, omiting the synthesis of Michael acceptor and avoiding the use of organic solvent. This strategy provides an easy alternative synthetic approach to the useful intermediate, γ-nitrocarbonyl compounds, with moderate to good yields.



An Efficient and Green Approach to Synthesizing Enamines by Intermolecular Hydroamination of Activated Alkynes

ZENG Ruijie, SHENG Hongting, RAO Bo, FENG Yan, WANG Hao, SUN Yehua, CHEN Man, ZHU Manzhou

2015, 31(2):  212-217.  doi:10.1007/s40242-015-4388-8

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An efficient, atom-economic and green approach to synthesizing enamines was developed by intermolecular hydroamination of activated alkynes with high yields under catalyst- and solvent-free conditions. β-Dimethylamino-acrylate derivatives were also obtained with high yields. In the synthetic process of the derivatives, N,N-dimethylformamide(DMF) pretreated with metal Na, was used as reactant instead of dimethylamine gas. The proposed synthetic method can be used for the synthesis of (E)-ethyl-3-(dimethylamino)acrylate(3cl), and provide a new possible way to the synthesis of Quinolones.



Synthesis and Evaluation of Novel N-(4'-Arylpyrimidin-2'-yl) Sulfonylurea Derivatives as Potential Antifungal Agents

CHEN Wei, LI Yuxin, SHI Yanxia, WEI Wei, CHEN Youwei, LI Yonghong, LIU Jingbo, LI Baoju, LI Zhengming

2015, 31(2):  218-223.  doi:10.1007/s40242-015-4362-5

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Sulfonylureas(SUs) are potent and selective inhibitors of acetohydroxyacid synthase and has been used as herbicides. Some SUs also displayed other biological activities. In order to discuss the antifungal activity of SUs, a series of novel SUs containing aryl-substituted pyrimidine moieties was designed and synthesized. The preliminary bioassay showed that the title compounds exhibited moderate to favorable fungicidal activities in vivo. Especially, compound 9b exhibited more efficacy than the controls against five fungi at 25 mg/L. These promising results indicate that an aryl group on pyrimidine ring is favorable for antifungal activity and SUs are potential inhibitors for some phytopathogenic fungi.



Convenient Synthesis of 1-Thiohydroxypyrene by Newman-Kwart Rearrangement

ZHANG Ran, XU Lihua, CHEN Hui, QIN Zhihong, ZHAO Yu, Ni Zhonghai

2015, 31(2):  224-227.  doi:10.1007/s40242-015-4356-3

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1-Thiohydroxypyrene(1) and its two intermediates, 1-pyrenyl-O-thiocarbamate(2) and 1-pyrenyl-S-thio- carbamate(3), were synthesized using 1-hydroxypyrene as the starting material. The key synthetic step is Newman-Kwart rearrangement. The results indicate that the Newman-Kwart rearrangement is more effective in suitable solvent than conventional method based on pure organic compound. The structures of compounds 1―3 were characterized by FTIR, NMR, GC-MS and elementary analysis. The crystal structures of two new compounds(2 and 3) were determined by single crystal X-ray diffraction analysis. The whole synthetic process is simple, mild and with high yield.



Synthesis, Biological Activity and 3D-QSAR Study of Novel Pyrrolidine-2,4-dione Derivatives Containing N-Substituted Phenylhydrazine Moiety

ZHANG Lizhi, REN Zhengjiao, LU Aimin, ZHAO Zheng, XU Wenqin, BAO Qianqian, DING Weijie, YANG Chunlong

2015, 31(2):  228-234.  doi:10.1007/s40242-015-4348-3

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Twenty-seven novel pyrrolidine-2,4-dione derivatives containing N-substituted phenylhydrazine moiety were synthesized. Their structures were confirmed by ¹H NMR, ¹³C NMR and MS. The half effective concentration (EC₅₀) values of the title compounds against the phytopathogenic fungi Rhizoctonia cerealis were evaluated. Compounds 6l and 6q displayed good bioactivity with EC₅₀ values of 1.626 and 2.043 μg/mL, respectively. The 3D quantitative structure activity relationship(3D-QSAR) model of CoMFA was established with reliable cross-validated correlation coefficient q² value of 0.585 and Noncross-validated correlation coefficient r² value of 0.971. This model provided a tool for guiding further design and synthesis of novel pyrrolidine-2,4-dione derivatives with high fungicidal activity.



Design, Synthesis and Antitumor Activity of Novel Indolin-2-one Derivatives Containing 4-Thiazolidinone Moiety

LIU Zijian, HOU Yunlei, ZHANG Guogang, XU Ning, MI Bin, GONG Ping, ZHAO Yanfang

2015, 31(2):  235-243.  doi:10.1007/s40242-015-4335-8

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A series of novel indolin-2-one derivatives containing 4-thiazolidinone moiety(7a―7r) were synthesized and evaluated for their in vitro antitumour activities against MDA-MB-231(human breast cancer), H460(human lung cancer) and HT-29(human colon cancer) cell lines by standard 3-(4,5-dimethylthiazae-2-yl)-2,5-diphenyltetrazo- lium bromide(MTT) assay. Representative compounds(7d, 7k, 7m, 7p) with higher cytotoxicity were further examined against one normal cell line(WI-38, human fetal lung fibroblasts). The preliminary investigation shows that most of the compounds display moderate to excellent potency and high selectivity against different human cancer cell lines. In particular, the most potent compound 7m shows promising cytotoxicity against MDA-MB-231, H460 and HT-29 cell lines with IC₅₀ values of 0.78, 0.056 and 0.018 μmol/L, respectively. The potency is much higher than that of Sunitinib(IC₅₀=3.46 μmol/L against MDA-MB-231, IC₅₀=2.59 μmol/L against H460, IC₅₀=1.50 μmol/L against HT-29) by 4.4, 46.3 and 83.3 fold.



Ultrasensitive Label-free Detection of miRNA with Asymmetric Hairpin Probe, Exonuclease I and SYBR Green I

LIU Yingxin, SU Hongyan, LONG Jiabao, CAO Qingfeng, YAN Shuya, MENG Xiangxian, CAI Qingyun

2015, 31(2):  244-248.  doi:10.1007/s40242-015-4378-x

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Detection of miRNAs presents a particular challenge because of their limited size, high sequence homo-logy and greatly various expression level. In this work, an ultrasensitive, label-free and isothermal miRNA detection was developed based on asymmertric hairpin probe, exonuclease I(Exo I) and SYBR Green I. The method employed asymmetric hairpin probe to perform cycled polymerization and Exo I to reduce background signal. In the presence of the target miRNA, the target triggers probe-mediated cycled polymerization reactions to generate lots of dsDNA products. The dsDNA product effectively prevents itself from being degraded by Exo I and permitted the insertion of more fluorescence dye into it to enlarge the fluorescence signal. In the absence of the target miRNA, there was no probe-mediated polymerization reaction, and the probe was digested by Exo I added, which minimized the intercalation of fluorescence dye to reduce the background signal. The combination of the probe-mediated cycled polymerization with the Exo I-assisted background reduction allows us to achieve a detection limit of 5×10^-18 mol/L. Owing to its ultrasensitivity, excellent specificity, convenience and low-cost, this method might hold out great promise in miRNA detection.



One-step Synthesis of 5-Ethyl-2-methylpyridine from NH₄HCO₃ and C₂H₅OH Under Hydrothermal Condition

TIAN Zhenzhen, ZHANG Dong, GUO Biao, TIAN Ge, LIU Xinxin, YUE Huijuan, FENG Shouhua

2015, 31(2):  249-252.  doi:10.1007/s40242-015-4297-x

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A simple one-pot approach to synthesizing 5-ethyl-2-methylpyridine(EMP) was established using NH₄HCO₃ and C₂H₅OH as starting materials and commercial Cu₂O as catalyst and oxidant under hydrothermal condition. Different reaction conditions were researched and the optimal ones were achieved by studying the parameters, that could affect the yield of product and by considering the energy and resource saving. The present study provided an eco-friendly way to obtaining EMP with lower volatility using fewer toxic starting materials.



Crystal Structure and Thermochemical Properties of 2-Pyrazine Carboxylate Lithium Monohydrate [Li(pyza)(H₂O)]_n(s)(pyza=2-Pyrazine Carboxylate)

XU Dan, DI Youying, KONG Yuxia, DOU Jianmin

2015, 31(2):  253-260.  doi:10.1007/s40242-015-4438-2

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A 2-pyrazine carboxylate lithium monohydrate [Li(pyza)(H₂O)]_n was synthesized in a mixed solution of redistilled water and anhydrous ethanol. X-Ray crystallography was applied to characterizing its crystal structure. Low temperature molar heat capacities were measured in a temperature range of from 78 K to 400 K with a precision automatic adiabatic calorimeter. Two polynomial equations of experimental molar heat capacity as a function of temperature were obtained by the least-squares method. The smoothed molar heat capacities and thermodynamic functions of the compound were calculated based on the fitted polynomial equations. In accordance with Hess's law, a reasonable thermochemical cycle was designed based on the preparation reaction of the target compound. The standard molar enthalpies of dissolution for the reactants and products of the designed thermochemical reaction were measured by an isoperibol solution-reaction calorimeter, and the enthalpy change of the reaction was obtained, i.e.,Δ_rH_m^θ=-(30.084±0.329) kJ/mol. The standard molar enthalpy of the formation of the target compound was determined as Δ_fH^θ_{m{[Li(pyza)(h2o)]n(s)}}=-(260.844±1.178) kJ/mol based on the enthalpy change of the reaction and standard molar enthalpies of the formation of other reactants and products. In addition, UV-Vis spectroscopy and the data of the refractive indexes were used to confirm whether the designed Hess thermochemical cycle was reasonable and reliable.



Structures and Nonlinear Optical Properties of Lithium-adsorbed Polycyclic π-Conjugated Pentacene Systems

LI Shaochen, YU Guangtao, CHEN Wei, HUANG Xuri

2015, 31(2):  261-269.  doi:10.1007/s40242-015-4375-0

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Structures and nonlinear optical(NLO) properties of eleven new Li_n-P_m(n=1―5) species were investigated in detail with the help of ab initio computation, in which one to the maximum five Li atoms are doped over the polycyclic π-conjugated pentacene. These Li-doped pentacene systems exhibit large adsorption energies(ca. 107.0—141.3 kJ/mol) and considerable first hyperpolarizabilities(even up to 4.1×10⁴ a.u.), where the number of Li atoms, the doping site, and the distance between the neighboring Li atoms have important impacts on the β₀ value. In the doped pentacene systems with less Li atoms(one or two), the improvement of β₀ value can be attributed to the simple transfer of the charge from Li atom to pentacene. Differently, doped more Li atoms(three to five) can cause not only charge transfer but also excess electron, and this cooperation can endow the doped systems with the much larger first hyperpolarizabilities. These fascinating findings are advantageous for the design of new NLO materials based on the intriguing polycyclic π-conjugated systems.



Electrochemical Performance of LiMn₂O₄/LiFePO₄ Blend Cathodes for Lithium Ion Batteries

QIU Chengguang, LIU Lina, DU Fei, YANG Xu, WANG Chunzhong, CHEN Gang, WEI Yingjin

2015, 31(2):  270-275.  doi:10.1007/s40242-015-4367-0

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A series of LiMn₂O₄/LiFePO₄ blend cathodes was prepared by hand milling and ball milling in order to compensate the disadvantage of spinel LiMn₂O₄ and olivine LiFePO₄. The morphologies of the blends were studied by scanning electron microscopy, and their electrochemical properties were studied by charge-discharge cycling, cyclic voltammetry and electrochemical impedance spectroscopy. It is easy to obtain uniform LiMn₂O₄/LiFePO₄ blends by the hand milling technique, while significant particle agglomeration is caused by the ball milling technique. When the LiMn₂O₄:LiFePO₄ mass ratio is 1:1, the nano-sized LiFePO₄ powders not only uniformly cover the micron-sized LiMn₂O₄ particles but also effectively fill in the cavities of the LiMn₂O₄ space. Such morphology offers a good electrical contact and a high tap density, which leads to a high discharge capacity and good cycle stability.



Theoretical Studies on the Absorption Spectra and Intramolecular Charge Transfer of Push-pull Zinc Porphyrin Dyes for Dye-sensitized Solar Cells

XIA Hongqiang, WANG Jian, JIA Ran, WANG Qin, ZHANG Hongxing

2015, 31(2):  276-280.  doi:10.1007/s40242-015-4342-9

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The electronic structures, absorption spectra and intramolecular charge transfer properties of five push-pull zinc porphyrin analogs with different donor group and π bridge have been investigated by density functio- nal theory(DFT) and TD(time-dependent)-DFT approach. The results show that the asymmetrical substituted diphenylamine group is favorable to the Q-band absorption of porphyrin dyes. The absence of the acetylenic bond in the π bridge part leads to the result that the B-band and the Q-band are blue-shifted and their absorption strength become weaker compared with that containing acetylenic bond, respectively. The introduction of the benzothiadiazole into the π bridge improves the intramolecular charge transfer.



Structural and Transport Characteristics of UCl₃ in Molten LiCl-KCl Mixture: a Molecular Dynamics Simulation Study

JIANG Tao, WANG Ning, PENG Shuming, YAN Liuming

2015, 31(2):  281-287.  doi:10.1007/s40242-015-4331-z

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To obtain suitable data for the pyrometallurgical post-processing in the fusion-fission hybrid reactor, the structure and transport characteristics of molten LiCl-KCl mixture containing UCl₃ were studied by molecular dynamics simulation. The radial distribution functions, densities, and self-diffusion coefficients were investigated at various molar fractions of UCl₃. In the molten LiCl-KCl-UCl₃ salt mixture, the first peak for g_U-Cl(r) was located at 0.266 nm, which was slightly left-shifted than the X-ray diffraction data, i.e., 0.285 nm for pure molten UCl₃. The preexponential factors for U³⁺ decreased from 46.2×10^-5 cm²/s to 32.2×10^-5 cm²/s as the molar fraction of U³⁺ increased from 0.005 to 0.05.



CO and C₃H₈ Total Oxidation over Pd Catalysts Supported on Commercial Ce-Zr Solid Solution: Effects of the Calcination Temperature and Hydrothermal Treatment

ZHOU Renmei, ZHANG Xuanyu, LU Jiqing, HU Gengshen, LUO Mengfei

2015, 31(2):  288-293.  doi:10.1007/s40242-015-4326-9

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A series of Pd catalysts supported on commercial Ce-Zr solid solution(Pd/CZ) calcined at different temperatures(750, 900 and 1050 ℃) was prepared via an incipient wetness impregnation method. The activities of the fresh and hydrothermally aged Pd/CZ catalysts were tested for total oxidation of CO and C₃H₈. For CO oxidation, the activity of either fresh or aged Pd/CZ catalysts decreased with the elevating of calcination temperature of CZ support, with a fresh catalyst calcined at 750 ℃ possessing the highest activity and hydrothermal stability. For C₃H₈ total oxidation, the activity of Pd/CZ catalysts could be improved by increasing the calcination temperature of support. However, the aged Pd/CZ catalysts showed higher activity than corresponding fresh Pd/CZ catalysts. The turnover frequency(TOF) over Pd/CZ catalyst for CO oxidation increased with increasing reduction ability of the catalysts, with a fresh catalyst calcined at 750 ℃ having the highest value(0.27 s^-1). However, the TOF of Pd/CZ catalyst for C₃H₈ total oxidation was mainly affected by the size of Pd particles, and large Pd particles possessed a higher activity, with the highest TOF value(0.96 s^-1) obtained over an aged catalyst calcined at 1050 ℃.



Computational Bottom-up Design of Ytterbium(Ⅱ) Complex with Pyridyl Amido Ligand

PAN Chengling, TANG Guodong, ZHENG Bin, Ahmed ELSHEWY, XU Jiqing

2015, 31(2):  294-297.  doi:10.1007/s40242-015-4288-y

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Having been designed via bottom-up strategy based on density functional theory(DFT) calculations, a complex of ytterbium(Ⅱ) with pyridyl amido ligand was successfully synthesized by one-pot reaction in laboratory. DFT calculation shows that pyridyl amido ligands can stabilize the complex via steric and electron effect. This success in integrating computation with synthesis will inspire more explorations in the development of a new complex in lanthanide chemistry.



Thermodynamics and Kinetics of Bacterial Cellulose Adsorbing Persistent Pollutant from Aqueous Solutions

LU Min, LÜ Xuan, XU Xiaohui, GUAN Xiaohui

2015, 31(2):  298-302.  doi:10.1007/s40242-015-4275-3

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The adsorption capability of bacterial cellulose(BC) for anionic dye acid fuchsine was studied. Meanwhile, the processes of the adsorption were investignted and fitted by adsorption isotherm models, adsorption thermodynamics and adsorption kinetics models, respectively. The changes of BC before and after adsorbing acid fuchsine were investigated via scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR) to further explain the adsorption mechanism. The results show that acid fuchsine could be effectively adsorbed by BC. The adsorption process was fitted well by Langmuir equation and the pseudo-second order kinetics, indicating that the adsorption process was monolayer molecule adsorption with the main action of chemical adsorption. The adsorption process was spontaneous and endothermic. Glucuronic acid groups and hydroxyl groups were responsible for the adsorption of acid fuchsine on BC.



Effect of Polyhedral Oligomeric Silsesquioxane and Sorbitol on Properties of Isotactic Polypropylene

CHEN Guanyun, FENG Baixuan, ZHU Kongying, ZHAO Yunhui, YUAN Xiaoyan

2015, 31(2):  303-307.  doi:10.1007/s40242-015-4394-x

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Isotactic polypropylene(iPP) was modified by the introduction of polyhedral oligomeric silsesquio- xanes(POSS) and 1,3:2,4-bis(3,4-dimethylbenzylidene)sorbitol(DMDBS). Chemical combination of (3-mercapto)- propyl-heptaisobutyl POSS with DMDBS(POSS-DMDBS), and physical mixing of DMDBS with octaisobutyl POSS (iso-POSS/DMDBS) or trisilanolisobutyl POSS(tri-POSS/DMDBS) were applied respectively to modifying iPP, and the effects of POSS and DMDBS on crystallization, rheological and mechanical properties of iPP were systematically investigated. The results indicate that iso-POSS/DMDBS and tri-POSS/DMDBS were more effective than POSS-DMDBS on the improvement of the crystallization behavior of iPP due to the higher crystallization temperature, while the crystallinity of iPP containing POSS-DMDBS was enhanced, approximately approached to that of iPP containing tri-POSS/DMDBS. The tensile strength of iPP with POSS-DMDBS was significantly increased from 34 MPa to 40 MPa, as high as that of iPP with iso-POSS/DMDBS. The different effects caused by the specific interaction between POSS and DMDBS could possibly be applied in the modification of iPP.



Removal of Natural Organic Matter by Forward Osmosis Membrane: Flux Behaviour and Foulant Characterization

XIA Shengji, YANG Ruilin, ZHANG Xinhuan, NI Muzi, WAN Yukun, YAO Lijuan, GAO Naiyun

2015, 31(2):  308-314.  doi:10.1007/s40242-015-4374-1

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Fouling of cellulose triacetate(CTA) forward osmosis(FO) membranes by natural organic matter(NOM) was studied by means of a cross-flow flat-sheet forward osmosis membrane system. The NOM solution was employed as the feed solution(FS), and a sodium chloride solution(3 mol/L) was used for the draw solution(DS). The process was conducted at various temperatures and cross-flow velocities. The flux decline was investigated with 3 h forward osmosis operation. The substances absorbed on the membranes were cleaned by ultrasonic oscillation of the fouled membranes and were characterized by methodologies including fluorescence excitation-emission matrices (EEMs) and liquid chromatography with an organic carbon detector(LC-OCD), and the variations of membrane properties were also investigated by Fourier transform infrared spectrometer(FTIR) and a contact angle meter. It was noted that the rejection efficiency of NOM is remarkable and that ultrasonic oscillation is an effective method to extract the NOM fouled on the CTA membranes after FO process. A higher cross-flow velocity and lower temperature benefit the anti-fouling capacity of the membrane significantly. Although humic substances accounted for the majo- rity of the NOM, aromatic proteins and amino acids were the main fouling components on the membranes, with symbolic FTIR peaks at 2355, 1408 and 873 cm^-1. The present surface foulant made the membranes becoming more hydrophilic, as demonstrated by a significant decrease in contact angle(ranging from 20% to 46%) under all the operation conditions.



Preparation of Boron-coated Expandable Graphite and Its Application in Flame Retardant Rigid Polyurethane Foam

XU Dongmei, LIU Xiu, FENG Jie, HAO Jianwei

2015, 31(2):  315-320.  doi:10.1007/s40242-015-4101-y

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A novel boron-coated expandable graphite(BEG) material was prepared by first wrapping polyvinyl alcohol(PVA) onto expandable graphite(EG) and then condensing with boric acid. The obtained BEG was characterized by scanning electron microscopy(SEM), Fourier transform infrared(FTIR) spectroscopy, X-ray photoelectron spectroscopy(XPS), and thermogravimetric analysis(TGA). The fire performance and mechanical properties of the rigid polyurethane foam(RPUF) filled with BEG were investigated by limiting oxygen index(LOI), horizontal and vertical burning, cone calorimetry(CONE), and electronic tensile tests. BEG shows an improved compactness of the char layers upon thermal expansion, which is effective for the flame retardancy of RPUF. With a loading of 10%, RPUF/BEG exhibited a higher LOI, >10% reduction in heat release rate and carbon monoxide release, as well as a decrease in smoke release during the beginning of combustion compared to RPUF/EG. Moreover, the compressive strength and modulus of RPUF/BEG were increased. The improved flame retardancy of BEG on RPUF can be attributed to the suppression of the "popcorn effect" of EG by PVA-boric acid, and the improved mechanical property can be attributed to the presence of PVA.