The batch rectification unit consists of seven theoretical plates, a reboiler and a reflux drum. We fill the reboiler with a 2500 kmol of a mixture of acetone-methanol. Initially, the mixture contains a liquid mole fraction of acetone equal to 40 % mole. The vapor flow rate is set equal to 10 kmol/hr. The reflux ratio is equal to 10. The molar holdups of the reflux drum and the plates are equal to 100 and 5 kmol. The program computes and plots the liquid mole fractions as well as the temperatures in the different stages. Since the acetone-methanol mixture presents a minimum boiling azeotrope (a pinch point), the distillate mole fraction does not exceed 0.75. The temperature at the end of the integration is almost equal to the boiling temperature of methanol since it is the only component left in the batch rectifier.