讲座题目：Performing Chemical Reactions under Unusual Process Conditions in Micro-flow
Microstructured reactors, sometimes described as microreactors, are useful tools for chemical research as well as in steadily increasing numbers used for industrial applications. In fact, within the community microreactors are most commonly understood as flow-through systems containing three-dimensional micrometer-scaled structures providing significantly larger specific surface-to-volume ratios and, consequently superior heat exchange properties. This definition should be extended in a way that the priority is set to the enhancement of mass- and heat transfer to allow performing a chemical reaction close to the kinetic limits. “Adapt your equipment to the chemistry and not vice versa” is the most important idea behind the term “chemical micro processing”, and therefore it demands for an adapted flow regime which can be induced by microstructures but the reaction does not necessarily takes place in microchannels.
Without any doubt, chemical micro processing will change the way of experimental work in chemical laboratory. It allows to perform reactions under conditions which are closer to the reality in pilot- or even production facility, as it is in some cases by using old fashion style glassware. However, one can be tempted to transfer the protocols used for performing chemical reactions in commonly given equipment to a microreactor set-up. In some cases satisfied results can be achieved but it means at least to fill “old wine into new tubes”. The advantage of processing in microstructured reactors are the possibilities to overcome conventional drawbacks, e.g. adding of solvents, heating restricted by the boiling point or slow or irregular mixing by stirring, and therefore, the chemical protocol should be changed. To apply unusual process regimes under laboratory conditions as well as for industrial applications opens up so-called ‘Novel Process Windows’.
Many examples for the application of chemical micro processing can be found in literature [1,2]. Smart chemical plants open up possibilities for distributed production at the point-of use as well as production-on demand [3,4]. From the increasing number of filed patents during the last few years that the interest of application of micro processing in industry is much higher than it can be derived from publications in scientific journals.
Microprocess technology is still regarded as a rather radical change in chemical engineering. It will need probably another decade until it has become more routine business. On this way, intermediate solutions such as the use of meso-scale equipment, still of advanced nature, will complement the choice for smart continuous manufacturing. Also, other modern technologies such as microwave organic synthesis, ionic liquids, and super-critical processing will probably be used jointly with microreactors in selected cases. In this way, some current limitations of microprocess technology, e.g. concerning solubility, upper operating temperature, and heat supply, may be overcome.