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 properties from liquid to gas with small pressure and temperature variations.
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Soluble transition metal particles with sizes of a few nanometers are recognized today to possess a crucial role in many synthetically important transformations. 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 core of amphiphilic macromolecules. A CO<SUB>2</sub>-philic shell provides solubility in supercritical carbon dioxide (scCO<SUB>2</sub>). Particle size and morphology control by synthesis directly in scCO<SUB>2</sub> will be investigated. The catalytic properties in organic transformations will be studied in scCO<SUB>2</sub>, and compared to catalysis in organic solvents. Recovery of the CO<SUB>2</sub>-philic polymer/nanoparticle hybrids 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.
