Hydrodynamic Rocking Disc Electrode Study of the TEMPO-mediated Catalytic Oxidation of Primary Alcohols
Hydrodynamic Rocking Disc Electrode Study of the TEMPO-mediated Catalytic Oxidation of Primary Alcohols
复制标题
DOI：
10.1002/elan.201600141
复制
发表时间：
2016-09-01
期刊：
影响因子：
3
通讯作者：
Marken, Frank
中科院分区：
文献类型：
--
作者：
Ahn, Sunyhik D.;Fisher, Adrian C.;Marken, Frank
在正弦摇摆盘处的流体动力学变薄的扩散层是近似均匀的，并且可以用扩散层厚度δ（RoDE）= 9.0D（1/3v1/6）/根θ f表示，其中D是氧化还原活性物质的扩散系数，v是运动粘度，θ是总摇摆角（这里为90度），f为摇摆频率（这里为0.83至25 Hz）。对于2，2，6，6-四甲基哌啶-1-氧（TEMPO）在pH9.5的碳酸盐缓冲溶液中的单电子氧化反应，扩散层厚度的表达式与实验数据之间有定量的一致性.接下来，七伯醇，催化TEMPO介导的氧化机制进行了研究，在摇摆盘条件下。使用DigiElch 4评价化学速率常数（通过改变扩散层厚度）。F仿真包。化学速率常数的趋势（与DFT计算相比）表明甲醇与高级伯醇和芳族与非芳族伯醇的反应性增强。摇摆盘伏安法允许在层流状态下进行定量机理分析。
The hydrodynamically thinned diffusion layer at a sinusoidally rocking disc is approximately uniform and can be expressed in terms of a diffusion layer thickness delta(RoDE) = 9.0D(1/3v1/6)/root Theta f with D, the diffusion coefficient of the redox active species, v, the kinematic viscosity, Theta, the total rocking angle (here 90 degrees), and f, the rocking frequency (ranging here from 0.83 to 25 Hz). For the oneelectron oxidation of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in aqueous carbonate buffer pH 9.5, it is shown that there is quantitative agreement between the expression for the diffusion layer thickness and experimental data. Next, for seven primary alcohols, the catalytic TEMPO-mediated oxidation mechanism is investigated under rocking disc conditions. Chemical rate constants are evaluated (by varying the diffusion layer thickness) employing the DigiElch4. F simulation package. Trends in the chemical rate constants (compared with DFT calculations) suggest enhanced reactivity for methanol versus higher primary alcohols and for aromatic versus non-aromatic primary alcohols. Rocking disc voltammetry allows quantitative mechanistic analysis in the laminar flow regime.