Experimental and Modeling Study of the Thermophysical Properties of 1-Hexene/Long-Chain Alkanol Systems

This study presents a detailed examination of the viscometric and volumetric properties of binary systems of 1-hexene and a homologous series of 1-alkanols (1-hexanol to 1-decanol) within the temperature interval of 293.15–323.15 K. The central objective of this investigation was to provide a deeper understanding of the mechanisms and characteristics governing intermolecular interactions, thereby offering insights into the molecular forces that dictate the thermophysical behavior of the studied systems. Experimental data revealed that the excess molar volumes (VE) are consistently negative across the entire composition range for all studied mixtures. Furthermore, the magnitude of these negative deviations was found to increase systematically both with rising temperature and with the progressive extension of the alcohol carbon chain. Values of viscosity deviations (Δη) were negative for all systems investigated. The magnitude of the negative deviations diminished with increasing alkyl chain length, suggesting that the introduction of larger nonpolar moieties makes interactions stronger compared with shorter-chain alcohols. To further interpret the volumetric data, the PC-SAFT equation of state was employed for modeling liquid densities. The calculated values displayed excellent correspondence with experimental measurements, with only 0.81% deviation observed in the hexene + 1-decanol mixture.