Preparation of nanocrystalline materials
- © Copyright??
There is an enormous current interest in nanocrystalline materials in several fields of material science. In our group the research interests are focussed on the synthesis of nanoparticles in microemulsions. The use of microemulsions opens a way for producing extremly small particles of very different materials. The mechanisms of nucleation and particle growth in microemulsions are studied in order to provide a model for scaling-up of nanoparticle preparation procedures.
Application of microemulsions in organic, bioorganic reactions and polymerizations
- © Copyright??
There are a great number of industrially important
reactions in homogeneous catalysis with low reaction rates due to a
limited solubility of the reactants. This hinderance can be overcome
when performing the reaction in a microemulsion.
High reaction rates can be achieved in microemulsions tailored for various reactions. Reaction kinetics are studied in order to provide data for scale up criteria.
Enzyme catalyzed reaction in microemulsions
In biochemistry and biotechnology a number of stereoselective enzyme catalyzed synthesis have been developed over the last decade. In the case of very poorly watersoluble substrates there is much effort in searching for suitable organic media in order to increase the substrate concentrations and so the reaction rates. Microemulsions seem to meet the required demands. We study the stability and activity of enzymes in microemulsions as well as separation procedures for enzymes and products from the microemulsions. Ultrafiltration processes are developed for this purpose.
Micell supported catalysis and ultrafiltration
- © Copyright??
For the catalytic hydrogenation of C-C double bondings, the taken catalysts and ligands have a high part of the production costs of the products. Hence, a recycling of these compounds is very profitable. A promising posibility is the catalytic hydrogenation in aqueous-micelar-medium, so that the catalyst will be build into the micelles of the used surfactant. In this case, the catalyst can be recycled by ultrafiltration after the reaction takes place. Thereafter, the recycled catalysts can be used for the next accretion in its active mode. A very important step in the development of such a process is the discovery of a suitable combination of surfactant and membrane to recycle mor than 99% of the catalyst. The catalytic hydrogenations of itaconacid and acetamidocinnamonacid-ester serve as model reactions to make studies.
Characterization of surfactant based dispersed systems
Surfactants play a crucial role in all kinds of dispersed systems. Especially systems composed of water, oil and surfactant show a rich spectrum of isotropic phases and mesophases. Studying that region of the phase diagram that exposes microemulsions and lamellar phases gives a detailed insight into the physics of such systems. We study phase diagrams, interfacial tensions and solubilization parameters for surfactant systems of technical relevance, especially in order to support our other projects with suitable dispersed systems.