Micro reactors, i.e. chemical reactors with characteristic dimensions in the sub-millimeter range, hold great promise for novel chemical process routes (Lerou 1996, Wengeng 1996). Among their potential advantages for chemical processes are: the very small thermal inertia, allowing for a very direct control of temperature as a very critical reaction parameter; their inherent safety due to both the small reactant volume being present at any time in the reactor and the well controllable reactor and reaction conditions; and their small dimensions, making them easy to integrate into existing processes or to use them where space requirements are critical. Furthermore, for heterogeneously catalysed gas phase reactions, micro reactors offer the additional advantage of allowing for a very large surface to volume ratio. This should at least theoretically allow for an effective suppression of homogeneous gas phase reactions, since free surfaces typically are strong sinks for radical species which are required to keep the homogeneous reaction alive. Therefore, it should be possible to conduct a heterogeneously catalysed reaction involving a mixture of potentially flammable (if not explosive) gases in a micro reactor without any danger of open flames and explosion. This has the two-fold advantage, that not only the reaction becomes intrinsically safe, but it should also be possible to study heterogeneously catalysed high-temperature reactions without influences by parallel homogeneous reaction Pathways, making it a very valuable tool for research into this class of reactions.