Supercritical carbon dioxide as reaction medium: synthesis, catalytic properties and recovery of hybrids of amphiphilic macromolecules with metal nanoparticles

超临界二氧化碳作为反应介质：两亲性高分子与金属纳米颗粒杂化物的合成、催化性能及回收

• 批准号: 5407839
• 负责人: Professor Dr. Stefan Mecking
• 金额: --
• 依托单位: Arbeitsgruppe Chemische Materialwissenschaft
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5407839?language=en
• 关键词: Supercritical; carbon; dioxide; reaction; medium

Supercritical fluids exhibit a range of unusual properties which can be exploited for the development of new reactions in such fields as separation, chemical reactivity, or material processing. Beyond the capability of replacing toxic industrial solvents, the main interest of supercritical fluids is the possibility to tune continuously the fluid properties from liquid to gas with small pressure and temperature variations. Soluble transition metal particles with sizes of a few nanometers are recognized today to possess a crucial role in many synthetically important transfomations. However, their controlled preparation, stabilization and recovery after catalytic reaction remain key challenges. In the research proposed metal nanoparticles will be prepared and stabilized in the polar hyperbranched core of amphiphilic macromolecules. A CO2-philic shell provides solubility in supercritical carbon dioxide (scCO2). Particle size and morphology control by synthesis directly in scCO2, and as an alternative approach in aqueous media with subsequent construction of the shell will be investigated. The catalytic properties in hydrogenation of double bonds and in C-C coupling (Heck reaction) will be studied in scCO2, and compared to catalysis in organic solvents. Recovery of the CO2-philic polymer/nanoparticle hybrides from the products of a catalytic reaction by means of changing the properties of the carbon dioxide medium, particularly the density, will be investigated. This is of particular interest with respect to the recovery of catalytically active nanoparticles, as little stress on colloidal stability is imposed.

超临界流体表现出一系列异常特性，可以利用这些特性来开发诸如分离，化学反应性或材料加工等领域的新反应。除了取代有毒工业溶剂的能力之外，超临界流体的主要兴趣是，有可能在压力和温度变化的情况下连续调整从液体到气体的流体特性。如今，具有几纳米大小的可溶性过渡金属颗粒在许多合成重要的转运中都具有至关重要的作用。但是，它们的控制制备，稳定和催化反应后的恢复仍然是主要挑战。在研究中，提出的金属纳米颗粒将在两亲性大分子的极性超支核心中进行准备和稳定。二氧化碳壳具有超临界二氧化碳（SCCO2）的溶解度。将直接在SCCO2中进行合成的粒度和形态控制，并作为随后构造壳的水性培养基中的另一种方法。将在SCCO2中研究双键和C-C偶联（HECK反应）中氢化中的催化特性，并将其与有机溶剂中的催化。通过更改二氧化碳培养基的性能，尤其是密度，从催化反应的产物中恢复了二氧化碳/纳米颗粒杂化物。对于催化活性纳米颗粒的恢复，这是特别感兴趣的，因为施加了胶体稳定性的压力很小。