Distillation produced only an alcohol with a maximum of 95,6% alcohol content and 4.4% residual water content, because of formation of a binary azeotrope boiling at 78,4 oC. By addition of cyclohexane (in former times addition of benzene) a ternary azeotrope with lower boiling point can be formed, from which by distillation using rectification columns water can be separated. It results to ethanol of approx. 99.7% purity. Since traces of the solvent additive remains, the absolution takes place today almost exclusively at molecular sieves, which absorb selectively water molecules. The purity become over 99,9%. The residual moisture can be removed chemically by alcoholate formation, as sodium wire is pressed in.