Electron Transfer Mechanisms in Concentrated Organic Redox Solutions

研究了有机化合物在高浓度（1-10 M）氧化还原溶液中的电子转移反应。广泛使用微电极技术在含有摩尔浓度电活性物质的溶液中获得定量传输和动力学数据。最初的研究集中在几个最近发现的质量传输现象，包括由均匀电子转移反应引起的加速传输速率。除了微电极技术外，相位测量干涉显微镜和石英晶体微天平方法也被用于测量电化学耗尽层的物理参数。其他重点包括详细描述非均相电子转移速率常数对浓度的依赖性，以及耦合化学反应（包括催化反应）对局部电场依赖性的研究；详细研究了酮类化合物的电化学还原反应，确定了高电场对反应选择性的影响。商业电合成过程通常在高度浓缩的溶液中运行，因为这些溶液比稀释溶液具有更好的能源效率和更高的通量，但几乎所有的实验室电化学都是在稀释溶液中进行的，其中变量更容易分离和解释。通过创建浓缩溶液性质的基本框架，这项工作将使电化学过程的合理放大范例变得可行。这是由美国国家科学基金会和电力研究所赞助的电化学合成联合倡议下的一个奖项。

Electron-transfer reactions of organic compounds in highly concentrated (1-10 M) redox solutions are investigated. Extensive use is made of microelectrode techniques to obtain quantitative transport and kinetics data in solutions containing molar-level concentrations of electroactive species. Initial studies focus on several recently identified mass-transport phenomena, including accelerated transport rates resulting from homogeneous electron-transfer reactions. In addition to microelectrode techniques, phase-measurement interference microscopy and quartz-crystal microbalance methods are used to measure physical parameters of the electrochemical depletion layer. Other emphases include developing a detailed description of the dependence of heterogeneous electron-transfer rate constants on concentration and the investigation of the dependence of coupled chemical reactions (including catalytic reactions) on local electric fields; electrochemical reduction of ketones is studied in detail to determine the effects of high electric fields on reaction selectivity. Commercial electrosynthetic processes are usually run in highly concentrated solutions since these give a better energy efficiency and higher throughput than do dilute solutions, but almost all laboratory electrochemistry is done in dilute solutions where variables are more easily isolated and interpreted. By creating a fundamental framework for the properties of concentrated solutions, this work will make feasible a rational scale-up paradigm for electrochemical processes. This is an award under the joint Initiative on Electrochemical Synthesis sponsored by the National Science Foundation and the Electric Power Research Institute.