The method is used for mixtures having a low value of relative volatility, nearing unity.” In simple terms, extractive distillation is a means of separating two substances with similar boiling points by adding a third substance to change the boiling point of one of compounds, thus making them easier to separate.

Why do we use extraction in place of distillation?

Unlike distillation, which is based on boiling point differences, extraction separates components based on their relative solubilities in two immiscible liquids. Extraction is typically chosen over distillation for separation applications that would not be cost-effective, or even possible, with distillation.

What is difference between normal distillation and extractive distillation?

The main difference between the two is in the process of separating the mixture. Azeotropic distillation forms an azeotrope right after combining the separation solvent. ... In extractive distillation, a specific separation solvent is used in every mixture that should not form an azeotrope.