Safe and productive operating conditions for complex exothermic chemical processes are difficult to obtain because of the strong interaction between selectivity and safety constraints. In this work a generalization of the topological criterion to nonautocatalytic, chain, and autocatalytic catalyzed reaction schemes is presented. Such a criterion, useful for isoperibolic semibatch processes, is able to detect the so-called QFS boundary by performing a topological analysis of a suitable reduced phase portrait of the system of ordinary differential equations describing the process. Moreover, a safe and general procedure aimed to obtain the optimum values of both the dosing time and the initial reactor/coolant temperature, based on such a criterion, has been proposed and validated through the use of literature experimental data and laboratory tests concerning the case studies analyzed.