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Currently there are more then 30 000 specialty chemicals produced industrially from approximately 300 intermediate chemicals (Moulijn, Makkee, and Diepen, 2001 ). The vast majority of these intermediates are produced from a very limited number of approximately 20 simple base chemicals for example, ethylene, propylene, butane, ammonia, methanol, sulfuric acid and chlorine. To perform effi ciently the large spectrum of chemical reactions of interest an arsenal of specifi c reactor types and dedicated operating regimes has been developed and is applied in various industries. The design of effi cient and reliable reaction processes is the core subject of Chemical Reaction Engineering, a discipline which can be considered nowadays as rather mature. The progress achieved and important concepts developed are summarized in several excellent monographs (e.g., Froment and Bischoff, 1979 ; Schmidt, 1997 ; Levenspiel, 1999 ; Missen, Mims, and Saville, 1999 ; Fogler, 1999 ). The main starting point of an analysis of reacting systems is typically an evaluation and quantifi cation of the rates of the reactions of interest. Hereby, based on the specifi c physical an chemical properties of the reactants and products a wider range of temperature and pressure conditions has to be considered during the early development phases. The spectrum of reactor types available and operating principles applicable is very broad. Reactions and reactors are often classifi ed according to the phases present (Levenspiel, 1999 ). There are reactions that can be carried out in a single phase. However, in a reaction system often more phases are present requiring more sophisticated confi gurations and operation modes. Another useful classifi cation is based on the character of the process and distinguishes between continuous and discontinuous (batch) operations. Between these exist semi batch processes which are often applied to carry out highly exothermal reactions exploiting adjusted dosing concepts (Levenspiel, 1999 ; Fogler, 1999 ). To accelerate the desired reactions and/or to infl uence the selectivity in reaction networks with respect to the target products, frequently specifi c catalysts are