The pKa values of PFOA and other highly fluorinated carboxylic acids.
The dissociated and nondissociated species of any organic acid differ largely in their physicochemical behavior. The ratio of both species in aqueous systems is determined by the respective pKa value. For perfluorooctanoic acid recent fate-modeling studies have applied a pKa value of 2.8. This value likely is too high by 3 log units. Here, the correct value is estimated to be close to -0.5 based on analogy considerations and molecular modeling. Calculated pKa values for other highly fluorinated carboxylic acids are also presented.
Goss
Kai-Uwe
KU
UFZ Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany. kai-uwe.goss@ufz.de
D002210:Caprylates / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D004785:Environmental Pollutants / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D008956:Models, Chemical
D002210:Caprylates; D002264:Carboxylic Acids; D004785:Environmental Pollutants; D005466:Fluorocarbons; C023036:perfluorooctanoic acid