Abstract

The proposed study aimed to explore the kinetics of L-leucine (Leu) oxidation in a micellar media of cetyltrimethylammonium bromide (CTAB) by hexacyanoferrate(III) {HCF(III)}. The reduction in absorbance at 420 nm, which is indicative of the concentration of HCF(III), was measured to determine the reaction rate. Applying the pseudo-first-order state, The reaction’s progression was analyzed as an indicator of [HCF(III)], temperature, [Leu], [Cu(II)], [CTAB], ionic strength, and [OH^–]. The findings indicate that the [CTAB] is the crucial factor that significantly affects the rate of the reaction. The HCF(III) undergoes a 2 : 1 stoichiometric interaction with Leu and has a first-order reliance on [HCF(III)]. The observed reaction exhibits fractional-first-order kinetics with regards to [Leu], [OH^–], and Cu(II), within the range of concentrations investigated. The observed linear augmentation in reaction rate upon electrolyte’s introduction is suggestive of a positive salt effect. The inclusion of CTAB substantially enhances the catalytic activity of the process. After reaching its maximum rate, the reaction exhibits a very steady behavior even when the [CTAB] is further increased. The observed decrease in CTAB CMC could potentially be attributed to the diminished electrostatic repulsion among the cationic surfactant head groups, which is caused by the anionic [Cu(OH)₄]^2–, OH^–, and HCF(III) species.

中文翻译：

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CTAB 胶束介质对 Cu(II) 催化六氰铁酸 (III) 氧化 L-亮氨酸的影响

摘要

拟议的研究旨在探索六氰基铁酸（III）{HCF（III）}在十六烷基三甲基溴化铵（CTAB）胶束介质中氧化L-亮氨酸（Leu）的动力学。测量 420 nm 处吸光度的降低（指示 HCF(III) 的浓度）以确定反应速率。应用伪一级状态，将反应进程作为 [HCF(III)]、温度、[Leu]、[Cu(II)]、[CTAB]、离子强度和 [OH ^– ]的指标进行分析。研究结果表明[CTAB]是显着影响反应速率的关键因素。 HCF(III) 与 Leu 发生 2:1 化学计量相互作用，并且对 [HCF(III)] 具有一级依赖性。在研究的浓度范围内，观察到的反应对于 [Leu]、[OH ^– ] 和 Cu(II) 表现出分数一级动力学。引入电解质后观察到的反应速率线性增加暗示了积极的盐效应。 CTAB 的加入大大增强了该过程的催化活性。达到最大速率后，即使 [CTAB] 进一步增加，反应也表现出非常稳定的行为。观察到的 CTAB CMC 下降可能归因于阳离子表面活性剂头基之间静电排斥力的减弱，这是由阴离子 [Cu(OH) ₄ ] ^2–、 OH ^–和 HCF(III) 物质引起的。