Process for removing 2-butanol from tert-butanol/water mixtures

A process for separating 2-butanol from an industrial mixture which comprises 2-butanol, tert-butanol and water, wherein the proportion by mass of water is greater than the limit concentration of the distillation boundary line connecting an azeotrope of tert-butanol and water;

• and an azeotrope of 2-butanol and water, comprising
• (a) separating water from the industrial mixture by distillation to obtain a distillate, wherein the distillate has, in terms of the 2-butanol, tert-butanol and water in the industrial mixture, a proportion by mass of water, which at a pressure, is greater than the limit concentration of the distillation boundary line connecting an azeotrope of tert-butanol and water;
• and an azeotrope of 2-butanol and water;
• (b) subsequently changing the pressure so that the mixture has, in terms of the 2-butanol, tert-butanol and water in the distillate, a proportion by mass of water which is less than the limit concentration of the distillation boundary line connecting the distillation boundary line connecting an azeotrope of tert-butanol and water;
• and an azeotrope of 2-butanol and water;
• and
• (c) subsequently distilling the mixture at the same pressure into a stream comprising 2-butanol and a stream comprising tert-butanol and water.