In this work we study CO oxidation by numerical simulation; we used the monocrystal STM model (Sales et al., 1982; Slinko et al., 1999) and extended it to scale on a monolithic tubular reactor. The final model is a mixed system with ordinary and partial differential equations. We found that there is periodic behavior at earlier times, but the simulations at long time show bursting, which appeared as a route to chaotic behavior. Our results can be compared indirectly with a continuous flow reactor under isothermal conditions (Ballandis and Plath, 2000).