| 二羟基二(原碘酸根)合镍(Ⅳ)配离子氧化乙醇的反应动力学及机理 |
| Kinetics and Mechanism of Oxidation of Ethyl Alcohol by Dihydroxydiperiodatonickelate(Ⅳ) Complex Ion |
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| 摘要: 在碱性介质中用分光光度法研究了二羟基二(原碘酸根)合镍(Ⅳ)配离子(DDN)于25～40℃区间氧化乙醇的反应动力学。结果表明,反应对DDN为一级,对乙醇为正分数级。准一级速率常数kobs随[OH-]增加而增大,随[IO4-]增加而减小。有微弱的负盐效应。在氮气保护下,反应不能引发丙烯酰胺的聚合。提出一个包括Ni(Ⅳ)和乙醇生成加合物前期平衡的反应机理,导出的速率方程满意地解释了所有的实验结果,并计算出平衡常数、速控步骤的速率常数及相应的活化参数。 |
| 关键词: 二羟基二(原碘酸根)合镍(Ⅳ)酸根 乙醇 氧化还原 动力学及机理 |
| 基金项目: |
| Abstract: The kinetics of Oxidation of Ethyl Alcohol by Dihydroxydiperiodatonickelate(Ⅳ) complex Ion was studied by spectrophotometry in aqueous alkaline medium in a temperature range of 25～40℃. The reaction rate showed first order dependence in oxidant, and positive fractional order dependence in ethyl alcohol. It was found that the pseudo first order ([C2H5OH]》[Ni(Ⅳ)]) rate constant kobs increases with the increase of [OH-] and decreases with the increases of [IO4-]. A weak negative ionic strength effect was observed. Under the protection of nitrogen the re-action system does not induce polymerization of acrylamide indicating that an innersphere one-step two-election transfer is involved in the oxidation. A reasonable mechanism involving a preequilibrium of an adduct formation between Ni(Ⅳ) and ethyl alcohol has been proposed. The rate equations derived from the mechanism explained all the experimental results satisfactorily and the preequilibrium constants, rate constants of the rate-determining step together with the parameters were evaluated. |
| Keywords: dihydroxydiperiodatonickelate(Ⅳ) ethyl alcohol redox reaction kinetics and mechanism |
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| 宋文玉,白素英,张良苗.二羟基二(原碘酸根)合镍(Ⅳ)配离子氧化乙醇的反应动力学及机理[J].无机化学学报,2002,18(5):451-454. |
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