This paper deals with production scheduling of multipurpose batch. chemical plants under uncertainty. The uncertainty associated with process operations causes that production can not be carried out exactly as scheduled. Variations in task processing times and equipment availability can make the initial schedule inefficient. A combined strategy has been proposed to minimize effects due to these variations. It involves the generation of robust schedules and then the application of a reactive scheduling procedure to adapt the original schedule to the new scenario. An industrial based case study is used to show the advantages of this combined strategy.