Measurement and correlation of excess molar volumes for mixtures of 1-propanol and aromatic hydrocarbons

Excess molar volumes (V_m^E) have been measured at 303.15 K for 1-propanol+benzene or toluene or o- or m- or p-xylene mixtures using V-shape dilatometer. The V_m^E values, for an equimolar composition, vary in the order: benzene>toluene∼m-xylene>o-xylene>p-xylene. The V_m^E data have been used to calculate partial molar volumes, excess partial molar volumes, and apparent molar volumes of 1-propanol and aromatic hydrocarbons over the entire range of composition. The excess volume data have also been interpreted in terms of graph-theoretical approach and Prigogine-Flory-Patterson theory (PFP). While PFP theory fails to predict the V_m^E values for systems with s-shaped V_m^E versus x₁ graph, the V_m^E values calculated by graph theory compare reasonably well with the corresponding experimental values. This graph theory analysis has further yielded information about the state of aggregation of pure components as well as of the mixtures.