Fluorinated surfactants in solution: Diffusion coefficients of fluorinated alcohols in water

Abstract

A B S T R A C TIntra-diffusion coefficients of three fluorinated alcohols, 2,2,3,3,3-pentafluoropropan-1-ol (PFP), 2,2,3,3,4,4,4-heptafluorobutan-1-ol (HFB) and 2,2,3,3,4,4,5,5,5-nonafluoropentan-1-ol (NFP) in water have been measured by the PFG-NMR spin-echo technique as a function of temperature and composition, focusing on the alcohol dilute region. For comparison, intra-diffusion coefficients of 2,2,2-trifluoroethanol (TFE) and HFB have also been measured in heavy water using the same method and conditions. As far as we know, these are the first experimental measurements of this property for these binary systems. Intra-diffusion coefficients for NFP in water and for TFE and HFB in heavy water have also been obtained by molecular dynamics simulation, complementing those for TFE, PFP and HFB reported in a previous work. The agreement between experimental and simulated results for PFP, HFB and NFP in water is reasonable, although presenting higher deviations than for the TFE/water system. From the dependence of the intra-diffusion coefficients on temperature, diffusion activation energies were estimated for all the solutes in water and heavy water.

Perfluorinated Alcohols at High Pressure: Experimental Liquid Density and Computer Simulations

“…This work is part of a project in which experimental measurements, molecular dynamics (MD) simulations, and theoretical calculations are simultaneously used to study the properties of perfluorinated substances. We recently reported new experimental data, computer simulations, and theoretical predictions of vapor pressures, liquid densities, and surface tensions of pure perfluorinated alcohols, , as well as diffusion coefficients in aqueous solutions. , …”

“…We recently reported new experimental data, computer simulations, and theoretical predictions of vapor pressures, liquid densities, and surface tensions of pure perfluorinated alcohols, 2,3 as well as diffusion coefficients in aqueous solutions. 4,5 The tendency of alcohol molecules to form H-bonds sequentially, creating a flexible network of linear, cyclic, and ramified (lasso) aggregates of various sizes is well known. 6 The apolar alkyl chains are then stored the best possible way within the space between the H-bond network.…”

“…1−70 MPa) and temperature (293.15−313.15 K) are reported for five liquid 1H,1H-perfluorinated alcohols (CF 3 (CF 2 ) n CH 2 OH, n = 2,3,4,5,6). Derivative properties such as the isothermal compressibility and isobaric thermal expansivity coefficients were calculated from the experimental data and compared with that for hydrogenated alcohols from the literature.…”