Facile synthesis of monodispersed copper oxalate flaky particles in the presence of EDTA

Monodispersed copper oxalate particles with flaky morphology were prepared via a simple one-pot synthesis method. Scanning electron microscope (SEM), X-ray diffraction (XRD), and fourier transform infrared (FTIR) spectra were used to characterize particle morphology, size, phase composition, and functional groups. It was found that the presence of ethylenediaminetetraacetic acid (EDTA) and the solution pH value had strong influence on the morphological and size evolution of the precipitated particles. On the basis of controlled release of copper ions from a Cu2+–EDTA complex and Weimarn’s law, a strategy for the controlled synthesis of monodispersed copper oxalate particles was designed by referring to the basic mode of the Stöber method. The inherent nature of crystallization to form the flaky solid in the early stage of precipitation as well as the driving force of the long-lasting low supersaturation in the growth stage was proposed to explain the size and morphological evolution of the copper oxalate precipitates. Thermodynamic equilibrium concentrations of copper(Ⅱ) species in the Cu(Ⅱ)–EDTA–oxalate–H₂O solution system were calculated to help explain the possible formation mechanism of copper oxalate precipitates.     

吡啶硫酮锌的制备研究

对反应结晶法制备吡啶硫酮锌过程进行了实验研究,考察了溶液初始浓度、反应温度、反应时间、pH值、超声处理等因素对产品形貌和粒径的影响,采用扫描电镜(SEM)、激光粒度仪、X射线衍射仪(XRD)和红外光谱仪(FTIR)对产品进行分析与表征。结果表明:温度对产品形貌和粒径有影响,23℃以下时产品为爪形,23℃以上产品为棱柱状,且温度升高,粒径增大;其他条件对产品形貌和粒径影响不显著。     

Description of mechanism function about dehydration of cobalt oxalate dihydrate by multiple rates isotemperature method

0　IntroductionThetechnologyofthermalanalysishasbeenwidelyusedinthestudyofthermalbehaviorandthermalcharacterofsolidstatereaction ,theprimaryintentionofthermalanalysiskineticsistoestablishseparatevaluesofapparentactivationenergyE ,themostprobablemechanism g(α)andthepre exponentialfactorA ,meanwhilethedeterminationofg(α)hasgraduallybeenthefocusofthisfield .Inthisfield ,therearemostlygeneralkineticsmethodsused presently ,suchasCoats Redfern’s[1 ] integralmethod ,Achar’s[2 \〗differentialmet…     

钴掺杂对草酸锌热分解过程的影响

在空气气氛下,利用热重/差热扫描同步热分析仪(TG/DSC),对掺钴草酸锌(CoxZn1-xC2O4.2H2O(摩尔分数x为0和5%))的热分解过程及其动力学进行分析。动力学分析采用多升温速率法,通过Fredman方程和OFW方程2种不同方法对活化能和指前因子进行计算,考察钴掺杂对整个过程的影响。实验结果表明:钴掺杂使草酸锌热分解反应的热量变化由吸热变成放热;随着钴的掺入,反应的活化能降低,即钴掺杂使反应的难度降低;用多元线性回归方法确定的活化能分别为E=178.5 kJ/mol(x=0)和E=150.0 kJ/mol(x=5%),最可几机理函数均为Cn(自催化反应)模型。     

Segmented tubular synthesis of monodispersed microsized copper oxalate

Monodispersed microsized copper oxalate particles were prepared in a segmented continuous flow tube reactor, and the effect of the main parameters such as organic additive agent, initial copper ions concentration, residence time, and segmented media on the final products were investigated experimentally. The obtained copper oxalate microsized particles were disc-like in the presence of citrate ligand,which was the shape inducer for the precipitated copper oxalate. Thermodynamic equilibrium diagrams of the Cu(Ⅱ)-oxalate-H_2O,Cu(Ⅱ)-oxalate-citrate-H_2O, and Cu(Ⅱ)-oxalate-EDTA-H_2O solution systems were drawn to estimate the possible copper species under the experimental conditions and to explain the formation mechanisms of copper oxalate particles in the segmented fluidic reactor. Both theoretical and experimental results indicated that the presence of chelating reagents such as citrate and EDTA had distinct effect on the evolution of particle shape. Air and kerosene were tested as media for the fluidic flow segmentation, and the latter was verified to better promote the growth of copper oxalate particles. The present study provides an easy method to prepare monodispersed copper oxalate microsized particles in a continuous scaling-up way, which can be utilized to prepare the precursor material for conductive inks.     

8-氨基-7-羟基黄酮的简便合成

7-羟基黄酮和对硝基苯胺重氮盐在碱性每件下偶合,偶氮基引入黄酮分子的8住,生成7-羟基-8-(对硝基苯基偶氮基)黄酮.该偶氮化合物经保险粉还原后得到8-氨基-7-羟基黄酮.用红外光谱、核磁共振氢谱和质谱表征了所合成的化合物的结构.     

Sm-CuI促进芝麻素前体的简易合成

在碘化亚铜和分子筛存在下,以胡椒醛和马来酸酯为起始原料,直接使用金属钐促进一步反应制备了芝麻素双内酯型前体。反应以双加成形式完成,反应过程高效简便,合成方法简单新颖,原料易得。反应体系在无水、室温空气中进行。对反应影响因素进行了探讨,最终在优化条件下,胡椒醛与马来酸二甲酯反应所得芝麻素前体产率可达78%。在此基础上,进一步对其他马来酸酯如马来酸二乙酯、马来酸二丁酯和富马酸二甲酯的反应效果进行了研究对比,取得了预期的实验结果,并对反应机理进行了探讨。     

Facile synthesis of gold nanoribbons by L-cysteine at room temperature

Highly crystalline gold nanoribbons have been synthesized via a simple method by L-cysteine reduction of aqueous chloroaurate ions at room temperature, without additional capping agent or surfactant. Based on transmission electron microscopy (TEM) and UV-vis absorption studies for the intermediate products, the formation of gold nanoribbons is regarded as a kind of oriented attachment growth. Supported by the National Natural Science Foundation of China (Grant Nos. 90406023 and 90406024), National Important Basic Research Program of China (Great Nos. 2006CB933206 and 2006CB705606) and Foundation for Top Doctoral Candidate of Southeast University.     

Facile synthesis of polypyrrole nanowires for high-performance supercapacitor electrode materials

Polypyrrole nanowires are facile synthesized under a mild condition with FeCl_3 as an oxidant. Polypyrrole nanowires with the width of 120 nm form many nanogaps or pores due to the intertwined nanostructures. More importantly, PPy nanowires were further applied for supercapacitor electrode materials.After electrochemical testing, it was observed that the PPy nanowire based electrode showed a large specific capacitance(420 Fg~(-1), 1.5 Ag~(-1)) and good rate capability(272 Fg~(-1), 18.0 Ag~(-1)), which is larger than that of most of published results. The as-prepared electrode can work well even after 8000 cycles at 1.5 Ag~(-1).     

Facile synthesis of nanosized sodium magnesium hydride, NaMgH3

The ternary magnesium hydride NaMgH 3 has been synthesised via reactive milling techniques.The method employed neither a reactive H2 atmosphere nor high pressure sintering or other post-treatment processes.The formation of the ternary hydride was studied as a function of milling time and ball:powder ratio.High purity NaMgH 3 powder(orthorhombic space group Pnma,a 5.437(2),b 7.705(5),c 5.477(2) ;Z 4) was prepared in 5 h at high ball:powder ratios and characterised by powder X-ray diffraction(PXD),Raman spectroscopy and scanning electron microscopy/energy dispersive X-ray spectroscopy(SEM/EDX).The products formed sub-micron scale(typically 200-400 nm in size) crystallites that were approximately isotropic in shape.The dehydrogenation behaviour of the ternary hydride was investigated by temperature programmed desorption(TPD).The nanostructured hydride releases hydrogen in two steps with an onset temperature for the first step of 513 K.     

银-镍、铜、锌、铅草酸共沉淀盐的合成与热分解

采用共沉淀方法合成了银与镍、铜、锌、铅草酸共沉淀盐Ag2[M（C2O4）2].nH2O（M=Ni^2＋、Cu^2＋、Zn^2＋、Pb^2＋）,将合成物质加热到500°C可以得到金属合金或金属氧化物粉末。用热重（ThermogravimetricAnalysis,TGA）和差热（Differential Thermal Analysis,DTA）分析技术比较了银金属草酸共沉淀盐和相对应的镍、铜、锌、铅单一草酸盐在空气气氛中的热分解行为,推断出了所合成共沉淀盐的热分解过程,探讨了共沉淀盐的热分解特点。     

单分散哑铃形氧化铁粒子的水热合成

采用NaH2PO4作为矿化剂,将FeCl3在200～220℃下水热反应4h,得到了一种新型的单分散哑铃形α—Fe2O3粒子,并发现H2PO4^-和Fe^3 的起始浓度、水热温度显著影响水热产物的形状和结构．     

Zn~(2+)对电化学合成聚苯胺膜的影响

应用循环伏安法和扫描电子显微镜(SEM)研究了ZnSO4 对电化学合成聚苯胺(PAN)的影响.结果表明,在含0.1 mol/L苯胺的1.0 mol/L硫酸溶液中加入 0.1~1.0 mol/L的 ZnSO4,能提高 PAN膜的电沉积速度;Zn2+还能使电聚合的PAN膜在1.0 mol/L H2SO4 溶液中的电化学降解速度降低,并导致PAN膜的表面呈现多孔状的形貌.     

Zn^2＋对电化学合成聚苯胺膜的影响

应用循环伏安法和扫描电子显微镜(SEM)研究了ZnSO4对电化学合成聚苯胺(PAN)的影响．结果表明，在含0．1mol／L苯胺的1．0mol／L硫酸溶液中加入0．1～1．0mol／L的ZnSO4，能提高PAN膜的电沉积速度；Zn^2 还能使电聚合的PAN膜在1.0mol／LH2SO4溶液中的电化学降解速度降低，并导致PAN膜的表面呈现多孔状的形貌．     

Facile ball-milled synthesis of SnS2-carbon nanocomposites with superior lithium storage

A facile high-energy ball-milling method was developed to synthesize SnS_2-carbon(SnS_2/C-x(x = 40, 50, 60 wt%)) nanocomposites. The results showed that as anode materials for lithium-ion batteries(LIBs), the SnS_2-C nanocomposites exhibited high discharge capacity and excellent cycling stability. For the optimized SnS_2/C-50 wt% nanocomposite, a discharge capacity as high as 700 mA h g~(-1) and the initial coulombic efficiency of 80.8% were achieved at a current density of 100 mA g~(-1). The unique structure with SnS_2 nanoparticles(NPs)embedded into carbon network provided abundant Li-ion storage sites, high electronic conductivity and fast ion diffusion. The ball-milled synthesis is applicable for large-scale preparation of new sulfide-based anode materials with good performance for LIBs.     

7(6)-羟基黄酮的简便合成及相关谱学分析

以2,4（5）-二羟基苯乙酮和苯甲酰氯为原料,在碳酸钾催化下-步合成了相应的β-丙二酮型化合物1-[4-（苯甲酰氧基）-2-羟基苯基]-3-苯基-l,3-丙二酮（8a）和1-[5-（苯甲酰氧基）-2-羟基苯基]-3-苯基-1,3-丙二酮（8b）。化合物8a和8b分别在l％氢氧化钾水溶液中回流处理,分别得到7-羟基黄酮（9a）和6-羟基黄酮（9b）。用红外光谱、核磁共振氢谱和质谱对所合成的化合物进行了结构表征。     

Facile synthesis of nanostructured LiFePO4/C cathode material for lithium-ion batteries

Nanostructured LiFePO4/C cathode material was prepared by FePO4·2H2O/C precursor by in situ restriction reaction.The synthesized LiFePO4/C cathode material presents a narrow distribution of nano-sized particles and exhibits an excellent electrochemical property with various rates.The facile synthesis route for the preparation of nano-sized LiFePO4 material has the particular advantage of simple synthesis process and low synthesis cost.     

Facile synthesis of hierarchical hollow Mn-ZSM-5 zeolite for enhanced cyclohexane catalytic oxidation

ZSM-5 zeolite with hollow structure has gained considerable attention due to their unique properties and great potential applications in catalysis field.In this study,hierarchical hollow ZSM-5 zeolite was synthesized via a facile one-pot hydrothermal process during which a few amount of polyvinylpyrrolidone(PVP) was added.The synthesized ZSM-5 zeolite catalysts were characterized by the XRD,BET-BJH,TEM,FE-SEM,EDS,ICP-AES,XPS and intrusion/extrusion mercury analysis.The results showed that such hierarchical hollow ZSM-5 zeolite as micro-reactor after the modification by Mn species displayed excellent activity with a conversion of 98.7% and an overall selectivity of 97.6% for mild oxidation of cyclohexane to cyclohexanol and cyclohexanone(KA oil) at 70℃,making this type of catalyst a candidate for the production of industrial KA oil.Also,this approach is proved to be a desirable strategy for constructing hollow zeolite micro-ellipsoids by simple and cost-effective manner,thereby,providing a new avenue to be explored in catalysis field.     

基于生物质甘蔗渣的荧光碳量子点制备

本实验以富含纤维素的废弃生物质甘蔗渣为原料,采用水热法合成了具有荧光性能的碳量子点.对碳量子点进行了表征,其粒径大小约为5~10 nm;在紫外灯照射下发蓝色荧光,对其荧光性能进行了研究,发现其具有多元激发、多元发射的性质.对其细胞毒性进行了研究,结果表明是一种生物相容性良好的标记材料.     

海胆状Bi2S3球的合成及其在光电化学池中的应用（英文）

通过采用一种温和的化学途径成功制备了海胆状Bi2S3微球,合成过程既不用模板也不用添加剂.这些制备的Bi2S3微球显示了单晶的结构,呈现出[001]方向生长的趋势.通过光电化学池测试发现,这种海胆状的Bi2S3微球在可见光(λ≥420 nm)的条件下,显示了很好的光电流响应特性.