Abstract: An energy efficient process for the separation of two close boiling point components contained in a multi-component feed stream. The feed stream is distilled in a first column to produce a relatively light fraction containing substantially all the more volatile close boiling point component, along with part of the less volatile close boiling point component and a bottoms product. The relatively light overhead fraction from the first column is fed to a second column to produce an overhead product, consisting substantially of the more volatile close boiling point component and a bottoms product consisting substantially of the less volatile boiling point component. The bottoms product from the first column is fed to a third column to produce an overhead vapor consisting substantially of the less volatile close boiling point component, which overhead vapor is passed to the second column to supply part of the reboiling energy requirements for said column.