Discrete-time variable structure control is addressed. The robustness features of sliding-mode control and the recognized benefits deriving from the anticipatory actuation associated with programmed control are combined. The transient response shaping allowed by the multistage optimization approach is enhanced by the connection of a generalized predictive controller with a variable structure algorithm. The algorithm presented is applied to the control of a real chemical process. Resulting performances are tested by simulation, modeling the plant with a nonlinear continuous-time differential equations systems. Parameter variations are applied to plant parameters. The role and effect of the tuning parameters provided by the sliding-mode part of control is also investigated.