In this work, the time-optimal control of startup distillation columns by iterative programming proposed by Woinaroschy [Ind. Eng. Chem. Res. 2008, 47, 4158.] is extended to the case of nonideal mixtures. The minimization of distillation startup time is performed by iterative dynamic programming employing randomly chosen candidates for admissible control. The control variables are the reflux ratio and/or the reboiler heat duty. The dynamic distillation model proposed by the author in the mentioned work is applied with a preliminary computation of suitable correlation relations for equilibrium constants. An illustrative application for separation of a propene-propane mixture at plant scale is presented. Because of the small relative volatility of this mixture and respective high reflux ratio, the decrease of the reboiler heat consumption corresponding to the minimization of the startup time is significant.