Towards Aqueous – Fluorous – Hydrogenous emulsions: Phase equilibria and liquid structure of (water + 1H,1H-Perfluorobutanol + 1-butanol) ternary mixture

Abstract

The liquid-liquid equilibrium for the ternary mixture (1-Butanol + 1H,1H-Perfluorobutanol + Water) was determined at 298.6 K. The system displays a type 2 diagram (band-like) characterized by an immiscibility band resulting from the overlap of two regions of partial miscibility.The solubility of water in the binary mixtures of the two alcohols is very high, always above 0.34 mole fraction. The organic phase is thus a complex mixture of aqueous, fluorous and hydrogenous domains.Liquid densities were measured as a function of composition for (water + BuOH) and (water + HFB) binary mixtures and for the ternary mixtures along the organic saturation line. The excess volumes of the binary and ternary mixtures were calculated. The system displays remarkable volumetric effects: water dissolves in BuOH with volume contraction, in HFB with volume expansion and the excess volume of the ternary saturated organic mixtures is positive throughout most of the composition range.Atomistic molecular dynamics simulations were performed enabling a molecular level perception of the organization and interactions of the ternary system. The results accurately reproduce the experimental excess volumes data of the binary and ternary mixtures, fully validating the simulations. The simulation results reveal the existence of clusters of water molecules, coexisting with hydrogenated and fluorinated domains at concentrations near saturation.