Cohesive energy density and internal pressure of benzene and 1-alkanol binary mixtures

Abstract

The internal pressure (Pint), cohesive energy density (ced), and free volume (vf) for liquid mixtures of benzene with (C6 to C10) 1-alkanol are calculated at 303.15 K and atmospheric pressure. Flory's statistical theory was employed to drive the internal pressure of five binary mixtures. The conductor-like screening model for real solutions (COSMO-RS), in combination with experimental densities was applied to calculate the cohesive energy density of the binary systems. The ‘structuredness’ of the fluids above was studied using the Pint/ced ratio. The values are between 0.7 and 1.2, as is the case for non-associated molecular liquids, and demonstrates the non-chemical dispersions and repulsion types for binary liquids. The variations of these parameters with mole fraction and length of alkyl chain in the studied 1-alkanol were explained from the perspective of intermolecular interactions. It is observed that increase in the methyl groups of alcohol creates additional steric hindrances, loosens the structural packing, and reduces the order of interactions in these mixtures. Also, experimental densities and viscosities at various temperatures were reported for liquid mixtures to verify the existing interactions among unlike molecules.