Molecular Insight into the Liquid Propan-2-ol + Water Mixture.

The hydrogen bonding structure of the mixture propan-2-ol + water is analyzed at ambient conditions of temperature and pressure with molecular modeling and simulation techniques. A new force field for propan-2-ol is developed for this purpose on the basis of quantum chemical calculations and validated for a wide range of macroscopic properties. The basic mixing properties, excess volume and excess enthalpy, as well as the most important transport properties, that is, diffusion coefficients and shear viscosity, are considered to verify the suitability of the employed force fields for studying the complex behavior of this aqueous alcoholic mixture. Radial distribution functions and hydrogen bonding statistics are employed to characterize the hydrogen bond network and molecular clustering. Inhomogeneous mixing on the microscopic level, given by the presence of segregation pockets, is identified. The interrelation between the intriguing macroscopic behavior of this binary mixture and its microscopic structure is revealed.