Topological investigations of molecular interactions in mixtures containing 1,4-dioxane and alkanols

Molar excess volumes, VE, and molar excess enthalpies, HE, of 1,4-dioxane (i) + propan-1-ol, or + propan-2-ol, or + butan-1-ol, or + butan-2-ol (j) binary mixtures have been measured dilatometrically and calorimetrically as a function of composition at 308.15 K. The data have been analysed in terms of the graph theoretical approach (which involves the topology of the components of the mixture) to extract information about the state of components in pure and mixture states. The analysis of VE data by the graph approach has revealed that while propan-1-ol and propan-2-ol exist as associated molecular entities; 1,4-dioxane and butan-2-ol exist as monomers and these (i + j) mixtures contain a 1:1 molecular complex. The IR spectral studies of the (i + j) mixture lend additional support to the nature and extent of interaction for the proposed molecular entity in the mixtures. The energetic of the mixtures have also been studied. The VE and HE values predicated by graph approach compare well with their corresponding experimental values. The observed data have also been analyzed in terms of Flory and Lacombe and Sanchez theory.