In the last decades, tubular reactors have found an extensive application in chemical industry, spacing from conventional catalytic oxidations to the intensification of highly exothermic discontinuous processes. The main advantage offered by these reactors consists in a strong reduction of reaction volumes, which is possible due to the fast kinetics promoted by the segregated flow within the reactor. This feature is also well-known to be one of the causes for the complex temperature control along the tubular reactor when highly exothermic chemical reactions are carried out. For this reason, several studies concerning the safety of tubular reactor-based processes have been carried out. Many works have been focused on providing methods and dissertations with the ultimate goal of making processes based on tubular reactors ever more intrinsically safe and optimized. In this work, a mathematical model used to simulate a catalytic oxidation process in a tubular jacketed reactor is proposed. The effect of both unsteady state operating conditions and the Proportional-Integral controller on the location of the hot-spot and the definition of the runaway boundary are also analyzed. The final aim is the implementation of safety criteria capable of defining the parametric sensitivity boundaries of a controlled tubular reactor.