Experimental and multi-model analysis of excess molar enthalpies for iso-butanol + hydrocarbon systems at 298.15 K and 308.15 K

Excess molar enthalpies ( H m E ) data were measured for binary mixtures of iso-butanol with n -hexane, cyclohexane, benzene, ethylbenzene, and cumene at 298.15 K and 308.15 K under pressure 0.1 MPa and corroborated by the Redlich-Kister (RK) polynomial equation. The analysis of all binary mixtures revealed endothermic mixing across the whole composition range, reflecting a net positive balance between the energy required to disrupt the self-associated (hydrogen-bonded) structure of iso-butanol and the cohesive aromatic–aromatic interactions in the hydrocarbons, and the energy released upon formation of comparatively weaker alcohol–hydrocarbon interactions with the aromatic hydrocarbons. While evaluating the reliability of thermodynamic models for these mixtures, the FTB model reproduced the experimental H m E values with satisfactory agreement, with percentage average absolute deviations of 18 J · mo l − 1 , respectively. In contrast, PFP theory, for x 1 < 0.5 , reflecting its inability to fully account for H-bonding and specific interaction effects.