高等学校化学学报 ›› 1998, Vol. 19 ›› Issue (7): 1032.

• 论文 • 上一篇    下一篇

吸附方波伏安法研究单偶氮化合物表面电化学反应

徐刚1, O Dea J. J.2, Osteryoung J. G.2   

  1. 1. 江苏石油化工学院应用化学系, 常州, 213016;
    2. DepartmentofChemistry, NorthCarolinaStateUniversity, Raleigh, NC27695-8204, U.S.A.
  • 收稿日期:1997-09-15 出版日期:1998-07-24 发布日期:1998-07-24
  • 通讯作者: 徐刚,女,60岁,教授.
  • 作者简介:徐刚,女,60岁,教授.
  • 基金资助:

    美国国家科学基金(批准号:CHE9208987)资助课题.

Surface Reduction Study of Monoazo Dyes by Adsorptive Square Wave Voltammetry

XU Gang1, O Dea J. J.2, Osteryoung J. G.2   

  1. 1. Department of Applied Chemistry, Jiangsu Institute of Petrochemical Technology, Changzhou, 213016;
    2. Department of Chemistry, North Carolina State University, Raleigh, NC 27695 8204, U.S.A.
  • Received:1997-09-15 Online:1998-07-24 Published:1998-07-24

摘要: 在静止汞滴电极上用吸附方波伏安法研究了9个单偶氮化合物的表面电化学反应,观察到3种类型的方波伏安图,其中两类可用提出的4电子二步还原反应机理解释。第一步为准可逆还原,第二步为完全不可逆。第三种类型的伏安图可解释为4电子一步还原。以这两种反应机理为数学模型,用非线性最小二乘法分析实验伏安图,理论曲线与实验曲线吻合极好。获得了各偶氮化合物表面电化学反应的动力学参数,初步归纳出反应机理与取代基的关系,为研究其在生物体内的降解反应及致癌性提供了有参考价值的化学信息。

关键词: 方波伏安法, 单偶氮化合物, 表面电化学反应, 反应机理和动力学

Abstract: The surface reduction behavior of nine monoazo dyes at the static mercury drop electrode has been studied by means of adsorptive square wave voltammetry. Three types of surface reduction behavior are seen among the nine azo dyes. Two of them are modeled as a two-step mechanism in which the first step is a quasireversible reduction followed by a totally irreversible reduction. For those dyes having strong electron-repelling groups such as amino or dimethylamino, the second reduction occurs at a potential almost the same as that of the first, and only one peak is observed. The second step gradually separates from the first step as the pHvalue of the solution increases. For those azo dyes having methoxy or hydroxy substituents, two peaks are observed; one is quasireversible, the other is totally irreversible. The second irreversible step gradually overlaps the first step as the pHvalue of the solution decreases. The third type voltammogram of these monoazo dyes displays a single irreversible peak that is modeled as a four-electron one-step irreversible reduction. The surface reduction behavior is quantitatively explained by the proposed models. The kinetic parameters for these surface reactions are obtained by non-linear least squares(COOL) analysis of the voltammograms. These techniques are useful for both establishing mechanism and chemical analysis.

Key words: Square wave voltammetry, Monoazo dyes, Surface electrochemical reaction, Reaction mechanism and kinetics

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