The rheological behavior of particle/oil suspensions and w/o Pickering emulsions consisting of water, 1-dodecene and different fumed silica nanoparticles was investigated. The particles varied in hydrophobicity and specific surface area. The influence of particle concentration and water content on rheology was determined and the emulsion drop size distributions were examined. Emulsions with different drop sizes were created by either varying the particle concentration or the water content. It was found that the particles in the continuous oil phase and not the drop size distribution seem to be the major influencing factor on the Pickering emulsion rheology.

The use of Pickering emulsions has recently received increased attention in catalyzed multiphase reactions. Here, the ultrafiltration of Pickering emulsions is studied for product separation and to retain the catalyst in the reactor. To find the optimum between a high specific surface area for high reaction rates and a suited drop size distribution for high permeate fluxes, the preparation method of Pickering emulsion was investigated. It was found that the stability of the emulsion during filtration does not only depend on the solid particle content, but also on the drop size distribution.

Emulsions stabilized by solid particles are so called Pickering emulsions which are characterized by their high stability against coalescence. This type of emulsion can be used for a lot of applications. Very little is known about how reaction conditions affect their properties. In this study the influence of important reaction conditions like shear stress, pressure, temperature, and the influence of synthesis gas on Pickering emulsions is investigated. It is shown that the emulsions remain stable in terms of coalescence in a broad range of the reaction conditions and are suitable as reaction media for industrial processes and for a reaction optimization with a subsequent separation step.

The activity of the catalyst is the same at the particles and at the void surface between the particles.

Mass transfer in stirred liquid-liquid systems with and without silica nanoparticles is investigated for the saponification of benzoyl chloride. The mass transfer area is positively affected by the nanoparticles which lead to an increase of the liquidliquid interfacial area due to droplet coalescence hindrance. However, an additional mass transfer resistance induced by particles at the liquid-liquid interface was observed for all particle concentrations, since the high occupancy diminishes the available area for mass transfer. The ratio of the two oppositional effects needs to be determined to identify suitable nanoparticle reaction systems.