The Effect of KOH and KCL Addition to the Destilation of Ethanol-Water Mixture
The Effect of KOH and KCL Addition to the Destilation of Ethanol-Water Mixture

Summary/Abstract: This paper discuss the addition of KOH and KCl to the destilation of ethanol-water mixture. The investigation were on the azeotrope point in destilation curve, the yield of ethanol as the destilation product, and also on colligative and thermodynamic properties. Meanwhile, the thermodynamics parameters were the change on Gibbs energy of mixing, ΔGmix , the entropy of mixing, ΔS­­mix and the evaporation enthalpy of mixture, ΔHvap. The result shows that the addition of electrolyte KOH and KCl eliminated azeotropic point as it is described in T-x distillation curve. In addition, the ethanol yield increased, the Gibbs energy of mixing, DGmix, reduced, that indicates the mixing process occurred spontaneously. The spontaneity is also supported by the value of the entropy of mixing, DSmix, which is positive. It refers to the increasing of irregularity, confirming the spontaneity of mixing process. Meanwhile, the enthalpy of evaporation, DHvap, of ethanol-water mixture 300.1105 kJ/mol. The enthalpy increase to 738.4329 kJ/mol when KOH was added and the enthalpy value is 340.2338 kJ/mol when KCl was added. It indicates that water as main component in the mixture became more difficult to vaporize and it allowed the ethanol molecules to be freely released during destillation.

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