Structural and Dynamic Characteristics of a Water-Ethanol-2-Methoxy-4-(2-hydroxypropyl)phenol Mixture under Subcritical Conditions

The molecule of 2-methoxy-4-(2-hydroxypropyl)phenol (HPP) is a structural unit of conifer lignin. The results of molecular dynamics simulation of the structural and dynamic parameters of a three-component mixture water-ethanol-HPP at a temperature of 573 K and a density of 0.737 g/cm(3), which corresponds to the subcritical conditions of the fluid state, are presented. The radial distribution functions between the centers of mass of HPP molecules and mixed solvent molecules, the number of water and ethanol molecules in the solvation shells, the average numbers and average lifetimes of hydrogen bonds, and the coefficients of the self-diffusion of solvent molecules are calculated. It is shown that HPP molecules form hydrogen bonds with each other, as well as with water and ethanol. Also, hydrogen bonds between HPP molecules are the most stable and long-lived ones.