Energetics of molecular interactions of 1,4-dioxane with formamides or anilines at 308.15 K

Molar excess enthalpies (HE) of 1,4-dioxane (A) + aniline or formamide or N,N-dimethylaniline or N,N-dimethylformamide (B) mixtures have been measured at 308.15 K over the entire composition range using flow isothermal micro calorimeter. The HE values for 1,4-dioxane + N,N-dimethylaniline or N,N-dimethylformamide were found to be small and positive and, these are large and negative for mixture containing aniline, whereas these change sign from negative to positive for 1,4-dioxane + formamide. The HE versus mole fraction of 1,4-dioxane (xA) plots for 1,4-dioxane (A) + aniline or N,N-dimethylaniline or N,N-dimethylformamide (B) system are symmetrical about xA = 0.5 and for equimolar mixtures, HE for these system follow the sequence: aniline < formamide < N,N-dimethylaniline < N,N-dimethylformamide. The excess enthalpy data have been utilized to study the energetics of molecular interactions in terms of graph theoretical approach.