Control of periodically operated reactors has in common with control of reactors operating at steady state the objective of minimizing the effect of disturbances on an objective function such as the cost of a product or the deviation of an outlet concentration of a pollutant from a statuary target. Simple feedback control employing feedback PID regulators, however, is not "adequate for most disturbances because of problems with tracking a time-varying output and the necessarily non-linear character of the reactors with respect to controlled as well as uncontrolled inputs. This contribution is a review of the literature and a discussion of research needs. The literature on the control of periodically operated reactors is not voluminous. Nevertheless this literature clearly indicates that model based predictive controllers can be used for this type of reactor". Further research on the limitations, maintenance and implementation costs of model based controllers in this application would be worthwhile. Experimental studies are wholly absent. Unique regulators for other periodic operations, such as adaptive control or forcing the output toward a reference trajectory using an open loop model based control strategy, certainly warrant study of their application to periodically operated reactors. Additionally, proper design of the reactor may lead to configurations that are simpler to control and that may not require complex control strategies for efficient operation. (C) 2007 Elsevier Ltd. All rights reserved.