Ethylcyclohexane + 2-Alkanol Mixtures: Thermodynamic Properties and Viscosity Modeling Using Friction Theory

A thorough evaluation of the thermophysical properties of ethylcyclohexane (ECH) mixed with 2-alkanols (2-propanol to 2-hexanol) is presented across the temperature range of 293.15 to 323.15 K. The focus of this study is on the density and viscosity behavior of these systems. The experimental results demonstrate positive deviations from ideality in excess molar volume, while viscosity deviations are negative for all examined mixtures. This observation suggests the presence of weak intermolecular interactions between ECH and the 2-alkanol. These findings are consistent with the self-association behavior of 2-alkanol and the nonpolar nature of ECH, which disrupts the associated structures of the alcohols. Furthermore, the Friction theory (f-theory) was employed to model the viscosity of the binary mixtures. The f-theory exhibits excellent agreement with the experimental data, with a maximum deviation of only 2.24% observed in the ECH + 2-butanol system. This minimal discrepancy underscores the f-theory's efficacy in accurately correlating the viscosity measurements.