Molecular-level insights to structure and hydrogen bonds network of 1,4-dioxane aqueous solution

We investigate aqueous 1,4-dioxane solution structure via molecular dynamics approach for the force fields by Smith et al. and OPLS-AA/CM1A with water model TIP4P. The overestimation of enthalpy of mixing is linked with the lower numbers of water-water and higher numbers of dioxane-water hydrogen bonds. The results provide the total number of hydrogen bonds per oxygen atom, as well as specific numbers of hydrogen bonds for water-water and dioxane-water pairs in solution. We show that specific quantities are required to observe the difference in the solution structure across the employed force fields, such as the hydrogen bond network percolation and the cluster analysis of dioxane molecules in solution. It is shown that for lower numbers of water-water hydrogen bonds the average dioxane cluster size is also lower. Total number of hydrogen bonds per oxygen atom and dioxane cluster sizes are in good agreement with X-Ray experiments by Takamuku et al. The water hydrogen bond network analysis adequately reproduces the experimental percolation thresholds by Hernandez et al.

Automated summary

The structure of aqueous 1,4-dioxane solution was investigated using molecular dynamics approach. The overestimation of enthalpy of mixing is related to the lower numbers of water-water and higher numbers of dioxane-water hydrogen bonds. The study provides the total number of hydrogen bonds per oxygen atom and specific numbers for water-water and dioxane-water pairs in the solution.