Fluid phase topology of ethanol+benzene+cyclohexane at 101.3 kPa

Abstract

In this article, isobaric vapor–liquid equilibria for the ternary mixture of ethanol + benzene + cyclohexane was experimentally investigated at atmospheric pressure. Vapor–liquid equilibria data for ethanol + benzene + cyclohexane at 101.3 kPa were obtained with a Othmer-type ebulliometer. Data were tested and considered thermodynamically consistent. The experimental results showed that this ternary mixture is completely miscible and exhibits three binary homogeneous azeotropes and a ternary minimum azeotrope at the studied conditions. Satisfactory results were obtained for correlation of equilibrium compositions with UNIQUAC activity coefficients model and also for prediction with UNIFAC method. In both cases, low root mean square deviations of vapor mole fraction and temperature were calculated. The capability of ethanol as modified distillation agent at atmospheric condition is discussed in terms of the thermodynamic topological analysis. However, owing to the complex topology of the ternary mixture it leads to a distillation scheme with three columns and difficult operation and thus, ethanol is not recommended as a separating agent for benzene + cyclohexane azeotrope.