In this study, catalytic oxidation of iso-octane is investigated for a very fuel-rich and for a fuel-lean condition in a batch reactor. For this purpose, skeletal mechanisms are derived and their results are compared with detailed reaction mechanism results. It is shown that skeletal mechanisms, which have 61-62% less species and 57-59% less reactions than the detailed reaction mechanism, allow an accurate prediction of species distributions in the batch reactor. Hydrogen selectivity decrease and soot precursors increase at fuel-rich condition. Further, the behavior of a gas composition downstream a catalyst is investigated for fuel-rich conditions in a plug-flow reactor. Skeletal mechanism yields similar results to the detailed reaction mechanism and experiment in plug-flow reactor. The results show that iso-octane is completely converted in the beginning of the reactor (0.01-0.05 m) for fuel-rich conditions, while other hydrocarbon species like methane, ethylene, propylene and acetylene are produced within 0.05 m.