Spectrophotometric analysis was applied to check the kinetics of bromothymol blue (BTB) oxidation by alkaline permanganate at constant ionic strength 0.2 mol dm⁻³. The redox reaction was observed to proceed through two independently distinct, detectable steps. The first step coexists with the formation of intermediate complexes involving transient species relatively quickly of the blue hypomanganate(V) and green manganate(VI). The slowly decomposed intermediate formed to produce soluble colloidal manganese(IV) and the BTB keto‐derivatives as second slow‐stage oxidation products. The oxidation reaction demonstrated first‐order dependence in [MnO₄⁻] and fractional first‐order kinetics at each of the BTB and alkali concentrations at an initial rapid stage for complexes formation. It was found that the oxidation process is of a base‐catalyzed nature. Novel spectrophotometric measurement of the blue hypomanganate(V) was introduced using a traditional spectrophotometer. An effective oxidation mechanism compatible with the kinetic data obtained in terms of the activation parameters assessed was analyzed, proposed, and discussed in line with the kinetic findings.

中文翻译：

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高锰酸钾对溴百里酚蓝的氧化过程和动力学

应用分光光度法分析了恒定离子强度为0.2 mol dm ^-3时碱性高锰酸盐对溴百里酚蓝（BTB）的氧化动力学。观察到氧化还原反应通过两个独立的，可检测的步骤进行。第一步与形成涉及蓝色次锰酸盐（V）和绿色锰酸盐（VI）的瞬态物种的中间配合物共存。缓慢分解的中间体形成，生成可溶性胶体锰（IV）和BTB酮衍生物，作为第二个慢速氧化产物。氧化反应表现在[MnO的一阶依赖性₄ ^-]和在初始快速阶段形成复合物的每个BTB和碱浓度下的分数一级动力学。发现氧化过程具有碱催化性质。使用传统的分光光度计介绍了新型的分光光度法测定蓝色次锰酸盐（V）的方法。根据动力学发现，分析，提出和讨论了与根据评估的活化参数获得的动力学数据兼容的有效氧化机理。