Heterogeneous azeotropic distillation with n-hexane

Heterogeneous azeotropic distillation is a widely used technique for separating binary azeotropic mixtures into their components. To produce pure ethanol,  heterogeneous azeotropic distillation using hexane instead of benzen as the entrainer has been developed recently because  n-hexane is a common compound found in gasoline and any trace amount of hexane in the anhydrous ethanol will not be a problem for its subsequent use as a fuel. The composition of the ternary azeotrope determined by numerical interpolation was reported as  0.105, 0.236 and 0.658 mole fraction of water, ethanol, and n-hexane, respectively, and the temperature is 329.21 K.

The heterogeneous azeotropic distillation with n-hexane can produce pure ethano with relatively low energy input.