The development and production of new products with improved or hitherto unknown properties increasingly requires the application of new and more complex technologies. To understand, to analyse quantitatively and to optimise the underlying processes a profound knowledge about a large number of physical and chemical data and parameters is of key importance. For example, to design a distillation column, information is needed about the boiling temperatures of the components that should be separated. To optimise a separation process using membranes, the specific migration rates of the individual components in the membrane must be known, as well as other data. If one is interested in efficiently isolating a drug component that was synthesised in a solvent by crystallisation, an understanding of the temperature dependence of the solubility is required.

It is one goal of the group "Physical and Chemical Foundations of Process Engineering" to determine physical and chemical data and parameters that are related to the chemical engineering and bioengineering processes investigated at the MPI. Examples are:

• Growth rates of crystals,
• Rates of transport processes in porous media (diffusivities, permeabilities),
• Reaction rates,
• Solid liquid phase equilibria (melting diagrams, solubilities),
• Heat capacities, phase transition enthalpies,
• Adsorption equilibria.

Besides determining various physical and chemical data, the group investigates several separation and reaction processes in detail. A main topic is currently the development and design of processes capable to isolate and purify fine chemicals. A particularly difficult task in this area is the separation of enantiomers. These are pairs of molecules which are - like our hands - mirror images to each other. To produce certain drugs, the pharmaceutical industry needs frequently the pure enantiomers. In order to isolate the desired specie, i.e. in order to separate it from its extremely similar antipode, special crystallisation strategies and preparative chromatography are under development. A current project goal is to exploit these techniques in a coupled consecutive manner.

Another research project is the development of new reactors with permeable membranes as their wall. Components involved in the chemical reaction process can pass these membranes with different rate. Membrane reactors offer various attractive possibilities to improve the performance compared to conventional concepts. For example, in several industrially relevant oxidation or hydrogenation reactions a high product yield requires the careful adjustment of the concentrations of oxygen or hydrogen. In this field an attractive possibility is offered by dosing the reactants over membranes in a controlled manner into the reaction zone.

Fig. 1: Summary of research projects of the Physical and Chemical Foundations of Process Engeneering (PCF) group