酸性溶液中硝基苯在WC电极上的电化学还原

以聚四氟乙烯为粘接剂制成碳化钨(WC)电极.采用循环伏安法、线性扫描法和恒电位阶跃法研究了硝基苯在酸性溶液中WC电极上的电化学行为.实验表明:WC电极对硝基苯的还原具有较好的活性,电极过程受扩散和电化学步骤混合控制;表观活化能为23.7kJ·mol 1,其中,电化学步骤的活化能10.91kJ·mol 1.     

离子注入钯的钛电极上硝基苯的电化学还原

在室温下将１×１０￣（１７）～５×１０￣（１７）Ｐｄ￣＋·ｃｍ￣（－２）离子注入到钛基体中．通过ＡＥＳ测量了注入电极表面的组成和各元素的浓度－深度分布．用循环伏安法研究硝基苯在碱性溶液中,Ｐｄ／Ｔｉ电极上的电化学过程,结果表明,注钯的钛电极对硝基苯的电化学还原显示高的催化活性．用现场ＥＳＲ与电化学方法联用检测到硝基苯的单电子还原产物硝基苯阴离子自由基,用现场ＵＶ光谱法也检测到硝基苯的电还原产物苯胺．根据实验结果讨论了硝基苯电化学还原的机理．     

暂态电化学表面增强拉曼光谱研究对硝基苯硫酚分子的电化学还原过程

对硝基苯硫酚是表面增强拉曼光谱研究中最常用的探针分子之一,对硝基苯硫酚在电极表面电化学还原反应的研究有助于对芳香族硝基化合物还原机理的认识. 本文应用暂态电化学-表面增强拉曼光谱技术,研究了对硝基苯硫酚在循环伏安和计时电流法过程中的表面增强拉曼光谱. 结果表明,实验实现了完全与电化学检测时间分辨率同步的表面增强拉曼光谱检测,以最快5毫秒的时间分辨率研究了对硝基苯硫酚分子在金电极表面的还原过程. 结果分析推测其此反应过程极快,在5毫秒的时间分辨率下仍难以捕获其中间物种. 本研究为人们更深层次研究和认识硝基苯类化合物电化学还原过程提供了参考和方向.     

酸性溶液中离子注入钯的玻璃碳电极上硝基苯的电化学还原

用循环伏安法在离子注入钯的玻璃碳电极上，研究了硝基苯在０．５ｍｏｌ／Ｌ硫酸溶液中的电还原过程，通过ＡＥＳ测量了离子注入电极的表面组成和各元素的浓度－深度分布，在４０ｋｅＶ下，注入剂量为１×ｌ０￣（１７）离子／ｃｍ＿２的钯注入到玻璃碳（ＧＣ）中可产生钯原子最大百分含量为２０％的近表面区。原基体注入钯后比未注入的ＧＣ对硝基苯（ＮＢ）的电还原有更高的活性，用气相色谱法检测到ＮＢ的还原产物苯胺，讨论了硝基苯在酸性溶液中电化学还原机理。     

四苯硼酸盐PVC膜铯离子选择性电极的研究

四苯硼酸盐为活性物质的PVC膜对金属离子的选择性同溶剂的性质相关。本文考察了以邻硝基苯辛醚(o-NPOE)、邻苯二甲酸二正辛酯(DOP)及癸二酸二丁酯(DBS)为溶剂的四苯硼酸盐PVC膜对金属离子的选择性,比较了四苯硼钠(NaTPB)、四苯硼钾(KTPB)、四苯硼铷(RbTPB)及四苯硼铯(CsTPB)等几种碱金属的四苯硼酸盐为活性物质的膜的电化学性能,研制了以o—NPOE为溶剂,NaTPB为活性物质     

Cu/C-Nafion复合电极上硝基苯的电化学还原

制备性电解的结果表明，硝基苯在Cu／C－Nafion膜复合电极上的还原产物只有苯胺，可能与电极／Nafion界面的弱酸性环境和其还原中间产物本羟胺在界面的扩散较仅有关．生成苯胺的电流效率随电流密度的增大而减小，随反应液中硝基苯浓度的增大出现一个最大值．这可能是硝基苯的电化学还原过程受某种粒子的扩散控制、峰电流取决于硝基苯在Nafion膜中的溶解度所致．     

硝基苯阴离子基的ESR谱的研究

本文研究了在不同PH值的水溶液中电化学还原产生的硝基苯阴离子基的ESR谱, 随PH值下降, 硝基苯阴离子基的ESR谱由54条线变为36条线, 这种变化主要是硝基苯分子与其阴离子基之间电子交换速度增大, ESR谱线增宽, 谱分辨率下降造成的, 谱的理论模拟也证明了这一点, 交换速度常数在强碱介质中约为3.3×10^6s^-^1.mol^-^1.dm^3。     

质子惰性介质中硝基苯在铂微盘电极上的电化学行为

采用循环伏安法, 以铂微盘电极为工作电极, 铂片为辅助电极, 饱和甘汞电极为参比电极, 研究了硝基苯在含有四丁基高氯酸铵(TBAP)电解质的N,N-二甲基甲酰胺(DMF)有机溶液中的电化学行为, 并探讨了扫描速度和底物浓度等因素对硝基苯电化学特性的影响. 结果表明,该反应属扩散控制的准可逆反应.     

一种新的反应性指数：赝轨道活性指数

Fukui提出的前线轨道理论在预测反应活性方面获得了极大的成功。在某些情况下,除了前线轨道之外,还必须考虑其它轨道之间的相互作用。本文提出赝轨道的概念,将所有内层轨道的作用包括在赝轨道参数之内。扩展了前线轨道理论的适用范围。并用硝基苯和苯睛的硝化反应的定位效应为例说明了赝轨道指数的应用。     

投影边缘在硝基苯类化合物构效关系研究中的应用

在三维投影的基础上,对投影的边缘进行了描述,并以其进行了定量结构活性相关研究.实验结果表明,与Am指数、指示变量和量化参数相结合,可使其数学模型得到明显提高.通过人工神经网络对硝基苯类化合物的毒性进行预测,结果令人满意.     

硝酸脲中酰胺态氮及总氮含量测定的研究

对硝酸脲中酰胺态氮及总氮含量进行测定。以甲醛－硫酸法分析硝酸脲中酰胺态氮时，发现酰胺态氮的含量总是与理论值相关差将近1倍。文中解释了造成这一结果的原因。并找到了导致这种结果的定量关系。从反应温度，时间等方面进行多次试验，找到了适宜的分析条件。     

Cobalt(II)/(III) complexes bearing a tetradentate thiosemicarbazone: Synthesis,experimental and theoretical characterization,and electrochemical and antioxidant properties

New cobalt complexes, Co1 and Co2 , were synthesized starting from acetylacetone-S-methylthiosemicarbazone. The square planar cobalt(II) and octahedral cobalt(III) complexes were characterized by FT-IR, UV–visible, ¹H NMR, and X-ray diffraction spectroscopies and mass spectrometry. Frontier orbitals of the complexes were theoretically obtained to better understand the complex structures and intermolecular interactions. The electrochemical behaviors of Co1 and Co2 were investigated and the results were evaluated by comparing with each other and with similar published compounds to determine their possible usage in various electrochemical technologies, such as energy storage devices, electrocatalysts, and electrosensors. Metal-based oxidation at around 0 V and metal-based reduction at around −1.0 V indicated that these complexes are valuable for the proposed applications. By determining the trolox equivalent antioxidant capacity and the radical scavenging activity of the cobalt complexes, the compatibility between the antioxidant qualification, redox, and theoretical calculation results was discussed.     

三种食用色素的电化学行为的理论计算与验证

用量子理论计算柠檬黄、日落黄、胭脂红的相对焓（Hm）、相对熵（Sm），计算柠檬黄、日落黄、胭脂红的还原电位分别为-0．969，-0．901，-0．854V（vs．Ag／AgCl／Cl）。探讨了琼脂对色素的电催化机理，采用循环伏安法在玻碳琼脂电极上研究了食用色素柠檬黄、日落黄、胭脂红的电化学行为，分别于-1．064，-0．910，-0．882V（vs．Ag／AgCl／Cl）产生还原峰，理论预测与试验结果基本一致。     

咪唑四氟硼酸盐离子液体中磷钼酸掺杂聚吡咯薄膜修饰电极的制备及其电催化活性

以1-丁基-3-甲基咪唑四氟硼酸盐(BMIMBF4)离子液体作为介质,利用电化学方法在铂电极表面制备了磷钼酸掺杂聚吡咯薄膜;采用扫描电子显微镜观察了所制备的薄膜的形貌,利用热重分析评价了其热稳定性,利用循环伏安法测定了其电化学活性和对甲醇的电催化氧化活性.结果表明,与传统的硫酸溶液相比,以BMI-MBF4离子液体作为反应介质制备的修饰电极的表面形貌更均匀,电化学活性和对甲醇的电催化氧化活性更强.     

On the multiplicity of cathodically generated dianions of dinitrobenzenes

The results of DFT calculations indicate that the triplet state of 1, 3-dinitrobenzene, unlike that of other isomers, is thermodynamically more stable than the singlet one. This conclusion is confirmed by the comparison of the theoretical calculation results for the thermodynamics of formation of dinitrobenzene dianions with the experimental values obtained by cyclic voltammetry.     

二茂铁双酰腙化合物的合成及电化学性质

以二茂铁双酰肼为原料,合成出两个二茂铁基酰腙类物质,通过元素分析、IR、1H NMR等分析手段确定了化合物的组成;电化学研究表明,化合物a在高电位区有两个不可逆氧化峰,应是酰腙活性基团被氧化的结果,通过量化计算,得到了化合物a的稳定结构。     

四氢呋喃/三氟化硼乙醚混合电解质中咔唑的电化学聚合

在四氢呋喃/三氟化硼乙醚混合电解质中直接阳极氧化咔唑制备聚咔唑.单体的起始氧化电位为0.92 Vversus SCE,远低于单体在含0.1 mol.L-1Bu4NBF4的乙腈溶液中的起始氧化电位(1.36 Vversus SCE).在此体系中获得的聚咔唑膜具有良好的电化学活性和稳定性,其电导率为7.0×10-3S.cm-1.聚合物可部分溶解于二甲基亚砜等强极性有机溶剂.UV-Vis,FT-IR,1H-NMR证明聚合物共轭长链的形成.该体系中获得的聚咔唑是一种蓝光发射材料,并具有良好的热稳定性.     

Electrochemical studies of the interactional mechanism and scavenging activity of antioxidants towards dinitroaromatics

Abstract  

In the work discussed in this paper, cyclic voltammetric results obtained for the interaction of ascorbic acid, β-carotene, and three structurally related flavonoids (quercetin, rutin, and morin) with the anion radical of 1,3-dinitrobenzene were used to determine their antioxidant activity. The extent of the antioxidant–anion radical interactions was measured as the antioxidant activity coefficient. Higher values of this coefficient obtained for the three flavonoids in DMF are indicative of their greater antioxidant activity than ascorbic acid and β-carotene in this solvent. On the basis of cyclic voltammetric responses, a possible mechanism of the reaction of the reduction product of 1,3-dinitrobenzene with the antioxidants is proposed. Hyperchem PM3 quantum mechanical semi-empirical calculations of charges on reactive sites of the antioxidants and the 1,3-dinitrobenzene anion radical were also carried out; the results obtained supported the proposed mechanism of interaction.     

Ion-Selective Electrodes Prepared with Polyaniline Membranes

Polyaniline is a conductive polymer that has electrochemical activity. For this reason, it has many different uses in electrochemical area. In this study, polyaniline was prepared by electrochemical oxidation of aniline in concentrated H₂SO₄ and HCl solutions. Then, membranes were obtained from a mixture of these polymers and paraffin at a weight ratio of 50%. Ion-selective electrodes were prepared with these membranes and AgCl/Ag electrodes. Properties of prepared membranes were investigated with potentiometric measurements made in HCl, KCl, H₂SO₄, and HClO₄ solutions of different concentrations. The E–logc plots obtained with these ion-selective electrodes were found to be linear in a distinct concentration range. Their slopes depend on the membrane type and the doping ion in the test solution. The difference between these membranes was explained according to the morphological structures of polyaniline membranes.     

Comparison of electrochemical properties of two-component C60-Pd polymers formed under electrochemical conditions and by chemical synthesis

The electrochemical behavior of C₆₀-Pd polymer formed under electrochemical conditions and by the chemical synthesis was examined. In these polymers, fullerene moieties are covalently bonded to palladium atoms to form a polymeric network. Both materials deposited at the electrode surface show electrochemical activity at negative potentials due to the reduction of fullerene cage. Electrochemically formed thin polymeric films exhibit much more reversible voltammetric response in comparison to chemically synthesized polymers. The morphology and electrochemical behavior of chemically synthesized C₆₀-Pd polymer depend on the composition of grown solution. Chemical polymerization results in formation of large, ca. 50 μm, crystallic superficial structures that are composed of regular spherical particles with a diameter of 150 nm. The capacitance properties of C₆₀-Pd films were investigated by cyclic voltammetry and faradaic impedance spectroscopy. Specific capacitance of chemically formed films depends on the conditions of film formation. The best capacitance properties was obtained for films containing 1:3 fullerene to Pd molar ratio. For these films, specific capacitance of 35 Fg^?1 was obtained in acetonitrile containing (n-C₄H₉)₄NClO₄. This value is much lower in comparison to the specific capacitance of electrochemically formed C₆₀-Pd film.