CONTINUOUS DISTILLATION OF AQUEOUS SOLUTION OF ETHANOL CONTAINING A MINUTE AMOUNT OF CROTONALDEHYDE

Vapor-liquid equilibria of water-ethanol system containing about 0.1% crotonaldehyde were measured at 1 atm. The equilibrium ratio of crotonaldehyde decreases rapidly with increasing concentration of ethanol and reaches unity when the mole fraction of ethanol is 0.98. Beyond this ethanol concentration it becomes lower than unity. The experiments of continuous distillation were carried out in a glass Oldershow-type column. The concentrations of the minor component in distillate and bottom were determined under various conditions. It is shown that in a range of higher concentration of ethanol, crotonaldehyde is difficult to remove by distillation. With some assumptions, a set of differential equations governing the behavior of ethanol and a minor component has been derived and solved numerically by the Hamming method. It is shown that the calculated curves are similar in shape to the observed ones. The model presented can be used to predict approximately the behavior of the minor component.