Azeotropic, Extractive, and Pressure Swing Distillation

The three methods used to break an azeotrope by means of distillation are azeotropic distillation, extractive distillation, and pressure swing distillation. 

Azeotropic Distillation In azeotropic distillation, an entrainer is added to generate a new low-boiling azeotrope by changing the molecular interactions. The drawback is that at least one additional separation step is needed to remove the entrainer, which is recycled into the azeotropic distillation column. To ensure a simple separation of the entrainer, the new azeotrope should form two immiscible phases after condensation (heterogeneous azeotrope). For a homogeneous azeotrope, separation by extraction in combination with distillation is frequently needed. 

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To break an azeotrope, azeotropic, extractive, and pressure swing distillation can be used. 

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