We discuss general aspects of the control of reactive separation processes and specifically the example of the control of a semibatch reactive distillation process. It is pointed out that more complicated controller structures, more sophisticated controller design methods, and alternative, model-based nonlinear controllers are needed compared to conventional processes. For the example process, we discuss both conventional control structures and model-based predictive control using a neural net plant model. (C) 2003 Elsevier Science B.V. All rights reserved.