Thermodynamics of 1-alkanol + aromatic compound mixtures. Systems with dimethylbenzene, ethylbenzene or trimethylbenzene

Binary mixtures of 1-alkanols and ethylbenzene, dimethylbenzenes or trimethylbenzenes have been studied in the framework of the DISQUAC model. The interaction parameters for the hydroxyl/aromatic contacts are reported. DISQUAC represents well a set of thermodynamic properties: vapor-liquid equilibria (VLE), liquid-liquid equilibria (LLE), molar excess enthalpies (HE) and the concentration-concentration structure factor (SCC(0)). The model predicts correctly HE of 1-alkanol + 1,4-dimethylbenzene + cyclohexane systems using binary parameters only, that is neglecting ternary interactions. The available database on HE and molar excess volume (VE) is examined in order to gain insight into the interactions present in the studied mixtures: (i) dipolar interactions are stronger in systems with benzene; (ii) interactions between unlike molecules decrease with the increase of the chain length of the 1-alkanol for solutions with a given aromatic hydrocarbon; (iii) self-association of 1-alkanols is more important in systems with alkylbenzenes than in those including benzene; (iv) benzene is a more active molecule than other aromatic compounds when breaking the alcohol structure.