The separation of a multicomponent azeotropic industrial waste solvent mixture by batch distillation (BD) and batch extractive distillation (BED) is studied. From a mixture methanol-THF-water-toluene methanol must be recovered in high purity. The optimization of both processes is performed by a genetic algorithm (GA) coupled with a professional flow-sheet simulator performing the dynamic simulation. The optimization variables are the reflux ratios of the operation steps, the location, flow rate and duration of entrainer (water) feeding. The objective function to be maximized is the profit.