Excess Molar Enthalpies of Binary Systems of n-Valeric Anhydride or n-Hexanoic Anhydride with n-Dodecane, n-Tetradecane, or n-Hexadecane at 298.15 K

Excess molar enthalpies, H-E, of binary mixtures of n-valeric anhydride or n-hexanoic anhydride with n-dodecane, n-tetradecane, or n-hexadecane were measured by an isothermal titration calorimeter at 298.15 K under atmospheric pressure. The experimental H-E values are positive for all binary systems over the entire composition range. In these six investigated systems, the maximum values of H-E exhibit at the composition ranging from 0.47 to 0.49 and 0.44 to 0.47 in the mole fraction of anhydrides for the mixtures containing n-valeric anhydride and n-hexanoic anhydride, respectively. The maximum values increase with increasinE chain length of the alkanes for the mixtures containing a given anhydride. A Redlich-Kister equation correlated the experimental H-E data to within the experimental uncertainty. The new enthalpy data were also correlated, respectively, with the Peng-Robinson (PR), the Patel-Teja (PT), and two versions of the cubic chain-of-rotators (CCOR) equations of state and the NRTL model as well. The CCOR equation of state with two binary interaction parameters yielded the best representation for the investigated systems.