Dynamics of Mediated Electrochemical Synthesis in Microemulsions

微乳液介导电化学合成动力学

• 批准号: 9632391
• 负责人: James Rusling
• 金额: $ 36万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-01 至 2000-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9632391&HistoricalAwards=false
• 关键词: Dynamics; Mediated; Electrochemical; Synthesis; Microemulsions

ABSTRACT CTS-9632391 The goal of this project is to develop a fundamental understanding of how surface dynamics on electrodes and kinetics in microemulsions influence control of reactivity in mediated electrochemical syntheses. Electrochemical studies are used to relate surfactant and reactant adsorption-desorption dynamics on electrode surf aces to catalytic reaction rates. The mediated reactions include carbon-carbon coupling, cyclizations, and olefin production. Catalytic efficiencies of mediators in the bulk fluid using bare carbon electrodes will be compared with those of new catalytic electrodes designed specifically to achieve high reaction rates in microemulsions. Macrocyclic metal complexes that catalyze reactions by efficient inner sphere pathways, such as vitamin B12 and Cobalt-, iron-, and nickel-porphyrins, are used as mediators. Layer-by-layer electrode coating strategies based on polymeric silicon-oxygen-carbon linkages to carbon electrodes are compared with a previously developed polymer deposition method. Electroanalytical methods are used to compare reaction rates in microemulsions and homogeneous organic solvents and catalytic electrodes. Synthetic electrolyses in a stirred batch electrochemical reactor with product analysis are used to assess the practical utility of the systems, and to optimize yields and reactant conversion rates. Compositions of microemulsions and properties of catalytic coatings are tuned for best reaction rates and yields for key reactions. Surface dynamics of reactants and surfactants on electrodes are measured by time-resolved flow voltammetry on bare and catalytic electrodes. Methods and theory developed earlier are employed. Molecular interactions between co-adsorbates will be assessed via Frumkin interaction parameters obtained from wave voltammetry. As possible limiting factors for the rates of mediated reactions, reactant and surfactant exit and entry rates are estimated for the new catalytic films using electroactive probes. Correlations between rates of all surface dynamic events and rates of mediated synthetic reactions are sought. The objective of this work is to provide fundamental guidance for the future design of efficient mediated electrochemical synthetic processes in relatively inexpensive, low toxicity, water-based fluid media. Mediated electrochemical addition reactions are major targets because these atom-economical processes can be utilized to prepare chemicals of many classes, including lactones, pheromones, prostaglandins, C-glycosides, optically active olefins and alcohols, and cyclic molecules. New catalytic surfaces design specifically for microemulsions combined with kinetic control by fluid composition may provide a basis for future cost-effective, environmentally benign processes for the synthesis of high value chemicals.

摘要CTS-9632391该项目的目的是对微乳液中电极和动力学的表面动力学如何影响介导的电化学合成中反应性的控制进行基本了解。 电化学研究用于将电极冲浪ac上的表面活性剂和反应物吸附 - 吸附动力学与催化反应速率相关联。 介导的反应包括碳碳耦合，环化和烯烃的产生。将使用裸碳电极的介体在整体流体中的催化效率与专门为实现微乳液中高反应速率设计的新催化电极的催化效率进行比较。 大环金属络合物通过有效的内部球体途径（例如维生素B12和钴，铁和孢子蛋白）催化反应，用作介体。 将基于聚合物硅 - 氧 - 氧与碳电极连接的一层电极涂料策略与先前开发的聚合物沉积方法进行了比较。 电分析方法用于比较微乳液和均匀有机溶剂和催化电极的反应速率。 使用产品分析的搅拌批次电化学反应器中的合成电解质用于评估系统的实际实用性，并优化产量和反应物转换率。 对微乳液的组成和催化涂层的特性进行调整，以获得最佳反应速率和关键反应的产量。 电极上反应物和表面活性剂的表面动力学是通过裸露和催化电极上的时间分辨流量伏安法测量的。 先前开发的方法和理论是采用的。 共吸收物之间的分子相互作用将通过从波伏安法获得的frumkin相互作用参数进行评估。 使用电活性探针估计了介导的反应，反应物和表面活性剂出口速率，反应物和表面活性剂出口和进入速率的可能限制因子。 寻求所有表面动态事件的速率与介导的合成反应速率之间的相关性。 这项工作的目的是为在相对廉价，低毒性的水性流体介质中的有效介导的电化学合成过程的未来设计提供基本指导。 介导的电化学添加反应是主要靶标，因为这些原子经济过程可用于制备许多类别的化学品，包括内酯，信息素，前列腺素，C-糖苷，光活性烯烃，光活性烯烃和酒精和环状分子。 专门针对微乳液结合流体组成控制的新型催化表面设计可能为未来的成本效益，环境良性过程提供了基础，以合成高价值化学物质。