Investigation of Nonideal Mixing Behavior in Linalool and 1-Alkanol Mixtures: Thermodynamics and Viscosity Modeling Approaches

The liquid densities and viscosities of linalool (LL) combined with 1-alkanols (1-butanol to 1-heptanol) were studied across a temperature range of 293.15–323.15 K. The experimental results revealed a negative deviation from ideal behavior in both viscosity deviation and excess molar volume for all of the fluids examined. These deviations in excess volume indicate that the intermolecular interactions between LL and 2-alkanols are significant, primarily driven by hydrogen bonding between unlike molecules. Furthermore, the observed behavior highlights the role of molecular structure and steric hindrance of the alcohol chain in influencing the thermodynamic properties of the mixtures. The friction theory was employed to estimate the viscosity of pure chemicals and binary fluids. For pure alkanols and linalool, the viscosity calculations demonstrated a maximum error of 1.43% for linalool. In the case of binary systems, the correlated values were in good agreement with experimental results, with the largest deviation observed for the linalool + 1-heptanol mixture, reaching 2.26%. This close alignment highlights the reliability of the f-theory in modeling viscosity for both pure and mixed systems, particularly for compounds with hydrogen bonding interactions.