2.2.5.1.Heterogeneous azeotropic distillation with cyclohexane. In this process cyclohexane is added to an azeotropic column, along with hydrated ethanol, and it forms a new tertiary heterogeneous azeotrope with ethanol and water. The azeotrope is removed at the top of the azeotropic column, while an hydrous ethanol is produced at the bottom. The ternary azeotrope is cooled and under goes a liquid-liquid separation; the organic phase (rich in cyclohexane) is recycled to the azeotropic column, while the aqueous phase is sent to a recovery column where a solution containing ethanol is produced and recycled to the azeotropic column (Junqueiraetal.,2009). This process, in spite of its high energy consumption (Cavalett et al.,2012), remains the most common configuration used in sugarcane mills. Up until the late 1990s azeotropic distillation was the only alternative for production of anhydrous ethanol in Brazil, but benzene was the separation agent used until 1997, when its use was prohibited due to safety issues. Cyclohexane is therefore used in replacement of benzene, allowing the use of existing infrastructure.