This study experimentally investigates the intermolecular forces governing n-undecane +2-alkanol ( C3–C7) at varying temperatures using density and viscosity measurements. Excess molar volumes (VE) and viscosity deviations (Δη) were calculated to characterize the mixing behavior. Positive VE values suggest that n-undecane disrupts the hydrogen bonding network within the 2-alkanols, leading to volumetric expansion. The trend of decreasing VE with increasing alkanol chain length indicates improved molecular packing. Negative Δη values suggest a reduction in viscosity compared to ideal mixing, with longer alkanols exhibiting more negative deviations, implying a greater disruption of cohesive forces. The PC-SAFT equation of state was used to correlate the mixture densities, yielding results in excellent accord with the experimental data by optimizing the adjustable parameters (kij), as confirmed by small absolute average deviations. The highest observed deviation between experimental and predicted densities was 0.64%, which was found in the undecane +2-heptanol mixture. The results offer valuable insights into the thermodynamic properties of alkane–alcohol mixtures, with implications for fuel formulation and chemical process engineering.
