The recovery of methanol from an industrial waste solvent mixture (acetone (A) – methanol (B) – THF (C) –water (D) – toluene (E)) by batch (BD) and batch extractive distillation (BED) is optimised. A production cycle consists of six consecutive batches. The 1st fore-cut is incinerated; 2nd fore-cut, after-cut and hold-up are recycled to the next batch. Both processes are studied for constant and varying fresh feed compositions. The optimization of the batches was performed consecutively by a genetic algorithm (GA) with a professional flow-sheet simulator for the dynamic simulation. Objective function is the profit of the actual batch. Optimization variables are reflux ratios of all steps, duration of fore-cut withdrawals and for the BED flow rate and duration of entrainer (water) feeding. The effects of the variation of fresh feed composition on the optimal values of parameters are studied. The results of BD and BED processes are compared.