The effect of fluorination on the physical properties and the free energies of hydration of 1-alcohols

Abstract

Because of the widespread use of fluorinated compounds and their subsequent release into the environment, these chemicals have been subjected to a great deal of scrutiny in the past years to determine the extent of their toxicity. In order to better understand the interactions of perfluorinated alcohols and fluorotelomer alcohols in aqueous environments, molecular dynamics simulations are utilized to determine environmental predictors, such as the free energy of hydration. In this work, the predictions of two different force fields, the united-atom Transferable Potentials for Phase Equilibria (TraPPE) and the all-atom Optimized Potentials for Liquid Simulations (OPLS) are compared against available experimental data. Both force fields yield reliable predictions for liquid densities, heats of vaporization and hydration free energies. Investigation of the local solvation environment around the hydroxyl group reveals that fluorination of carbons closest to the hydroxyl group has the greatest effect on the overall hydration free energy.