Theoretical investigation of molecular interactions in dioxane and water using hydrogen bonding model and density functional method

The molecular interactions between water and dioxane are studied using hydrogen bonding model and density functional method. The average number of hydrogen bonds obtained using hydrogen bonding model is maximum at 0.83 mole fraction of water in dioxane. This concentration corresponds to five water molecules and a dioxane molecule in a complex [Mashimo et al., J Chem Phys 1992, 96, 6358; Kanse et al., J Ind Chem Soc 2007, 83, 168]. The values of dielectric constant for the mixture obtained by hydrogen bonding model are in excellent agreement with the experimental values. Density functional theory calculations show that the most stable conformer of dioxane–5H2O hydrogen bonded complex has six short hydrogen bonds. Number of hydrogen bonds from density functional calculations and hydrogen bonding model are in excellent agreement at 0.83 mole fraction of water. In this hydrogen bonded complex five water molecules bridging the two oxygen atoms of dioxane molecule and thus is a cyclic structure, which is also in agreement with the experiment. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011