Question

A student planned to separate a mixture of 1:1 ethanol (B.P.78°C) and isopropanol (B.P. 82°C) using distillation. Do you expect the two liquids to separate well? What criteria should be met to insure an effective distillation?

Answer 1

Azeotropic distillation is the method of separating close boiling compounds or azeotropes from each other by carrying out the distillation in a multiplate rectification column in the presence of an added liquid, said liquid forming an azeotrope with one or both of the compounds to be separated. Its presence on each plate of the rectification column alters the relative volatility in a direction to make the separation on each plate greater and thus require either fewer plates to effect the same separation or make possible a greater degree of separation with the same number of plates.