Diffusion coefficients of 2,2,2-trifluoroethanol/water mixtures

Abstract

Aqueous mixtures of 2,2,2-trifluoroethanol have received significant attention in the last years because their applications, such as working fluid in Rankine cycle thermal engines or as solvent in studies of protein stability (protein folding). From the fundamental point of view, fluoroalcohols have an amphyphile character, due to the simultaneous presence of a hydrophobic (and alkane-phobic) fluorinated surface and a hydroxyl group. Mixtures of 2,2,2-trifluoroethanol with hydrogenated alcohols were studied recently in our research group (experimental determination of pVT surfaces as well as thermal, volumetric and structural properties by computer simulation) [1]. In the case of 2,2,2-trifluoroethanol/water this study suggested a preference of cross hydrogen bond. Hydrogen bonds play a determinant role in the structure of aqueous mixtures of alcohols, and should influence the dynamic properties of binary systems of fluorinated alcohols with water. The goal of this work is to study a dynamic property (diffusion coefficient) of binary mixtures 2,2,2-trifluoroethanol/water, comparing the results with equilibrium and structural properties already known for this and related systems.