The application of a variable control structure for tubular reactors, based on multiple temperature measurements, is explored. The proposed structure allows the controller to adapt to temperature error variations along the tubular reactor. Controllers can be designed from simple input-output first-order dynamical models obtained from step responses and are coupled with a dynamic law for assigning a variable weight to conventional feedback cascade control loops. The simulation results show that the variable structure based on linear proportional-integral controllers enhances the performance and robustness properties of conventional cascade schemes for controlling the outlet reactor concentration. Major advantages are shown in the face of a variety of concentration and temperature feed disturbances.