物理化学学报 >> 1988, Vol. 4 >> Issue (01): 44-49.doi: 10.3866/PKU.WHXB19880109

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铁离子催化十二钨酸络钴酸钾氧化羟胺反应的动力学和机理

陈浴淙; 周本茂; 任新民   

  1. 中国科学院感光化学研究所
  • 收稿日期:1986-07-15 修回日期:1987-04-13 发布日期:1988-02-15
  • 通讯作者: 任新民

KINETICS AND MECHANISM OF IRON (Ⅲ) CATALYZED OXIDATION OF HYDROXYLAMINE BY 12-TUNGSTOCOBALT (Ⅲ)ATE

Chen Yucong; Zhou Benmao; Ren Xinmin*   

  1. Institute of Photographic Chemistry; Academia Sinica
  • Received:1986-07-15 Revised:1987-04-13 Published:1988-02-15
  • Contact: Ren Xinmin

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摘要： 实验证明十二钨酸络钴酸钾(Co~(3+)W)在醋酸钠缓冲溶液中氧化羟胺是在微量杂质金属离子催化下进行的, Fe~(3+)具有强烈的催化作用, 化学反应摩尔比等于1; 在pH=3.9～5.0范围中,用分光光度法研究Fe~(3+)催化反应的动力学, 发现在Σ[Fe~(3+)]<3×10~(-6)mol L~(-1)时遵循下列速率方程:
-(d[Co~(3+)W])/dt=(k·(∑[Fe~(3+)]+c)·∑[NH_2OH])/[H~+]
T=293 Kk时, =4.2×10~(-3)s~(-1), c=1.3×10~(-7)mol L~(-1), 在293—323 K范围内求得相应的表观活化能、活化熵和活化自由能, 并讨论了可能的反应机理。

Abstract: The oxidation of hydroxylamine by 12-tungstocobalt (Ⅲ) ate (Co(Ⅲ)W) in the acetate buffer solution has been investigated. It was found that the reaction proceeds in the presence of some metal ions, especially Fe (Ⅲ). The stoichiometry of the reaction catalyzed by Fe(Ⅲ) has been estimated bromatometrically and a kinetic study has been performed spectrophotometrically in the pH range 3.9-5.0. The empirical rate equation of the reaction is
-(d[Co(III)W])/dt=k(∑[Fe(III)]+c)∑[NH_2OH])[H~+]~(-1)
when concn. of Fe(Ⅲ) is less than 3×10~(-6)mol L~(-1). The value of k is 4.2×10~(-3)s~(-1) at 293 K and C=1.3×10~(-7)mol L~(-1). Over the temperature range 293—323 K, the values of the activation parameters of the reaction have evaluated. A mechanism of the catalyzed reaction in accordance with the rate law has been suggested.