Authors: Sierra Rayne
In their study, Wang et al. [Environ. Chem. 2011, 8, 389] use the COSMOtherm software program in an attempt to shed some insights into the physicochemical properties of various poly- and perfluorinated compounds. During the conformation dependent pKa investigations on n-perfluorooctanoic acid (PFOA), the authors appear to make a critical error in their analyses. Wang et al. appear to have allowed a transition from an acid form geometry to a very different anionic form geometry, which is not a correct way of calculating free energy changes during acid dissociation. This error explains why these authors obtained widely ranging conformation dependent pKa values (0.9 to 2.9) for PFOA dissociation. As has been previously shown [Rayne and Forest, J. Mol. Struc. THEOCHEM 2010, 949, 60], there are negligible conformation dependent effects on the pKa value of PFOA.
Comments: 1 Page.
[v1] 2013-05-23 07:04:36
Unique-IP document downloads: 131 times
Vixra.org is a pre-print repository rather than a journal. Articles hosted may not yet have been verified by peer-review and should be treated as preliminary. In particular, anything that appears to include financial or legal advice or proposed medical treatments should be treated with due caution. Vixra.org will not be responsible for any consequences of actions that result from any form of use of any documents on this website.
Add your own feedback and questions here:
You are equally welcome to be positive or negative about any paper but please be polite. If you are being critical you must mention at least one specific error, otherwise your comment will be deleted as unhelpful.