The document discusses various distillation techniques including: - Extractive distillation which uses a solvent to separate mixtures that would otherwise not be easy to separate. - Azeotropic distillation which uses an entrainer to break an azeotrope and form a new lower-boiling azeotrope to improve separation. - Liquid-liquid extraction which exploits differences in solubility between compounds rather than boiling points to separate mixtures through the addition of an entrainer that induces liquid-liquid immiscibility.