分光光度法研究二过碘酸合铜(Ⅲ)氧化丙酮酸钾的动力学

Kinetics and mechanism of oxidation of potassium pyruvate by diperiodato cuprate (Ⅲ) in alkaline medium

用分光光度法研究了碱性介质中二过碘酸合铜（Ⅲ） 配离子氧化丙酮酸钾的反应动力学。结果表明反应对氧化剂是准一级，对还原剂为１．６ 级，反应速率随着高碘酸根浓度的增加略有增大。并且〔 Ｐｙ〕／ｋｏｂｓ对 １／〔 Ｐｙ〕；１／ｋｏｂｓ对 １／〔 Ｈ Ｌ〕均为有正截距的直线。根据实验结果提出了一种含有前期平衡的反应机理，据此导出了一个能够解释全部实验事实的速率方程，求得了速控步的速率常数，并给出了 ２９８．２ Ｋ 时的活化参数。

The kinetics and mechanism of oxidation of potassium pyruvate by diperiodatocuprate (Ⅲ) was studied by spectrophotometry in alkaline medium.The reaction rate showed first order dependance in oxidant and 1.6 order dependance in 〔Py -〕.It was found that the pseudo first-order rate constant k obs increase with the increase in 〔OH -〕 and increase with the increase in 〔IO - 4〕.The linear relationships between 〔Py -〕/ k obs and l/〔Py -〕 and between 1/ k obs and l/〔HL〕 were observed in our experiment.There is a positive salt effect.The active species and a plauisible mechanism involving free redical have been proposed.All the experimental phenomena can be explained by the rate equation derived from the mechanism.The rate constant of the rate-determining step together with the activation parameters have also been evaluated.