Jump to main content
US EPA
United States Environmental Protection Agency
Search
Search
Main menu
Environmental Topics
Laws & Regulations
About EPA
Health & Environmental Research Online (HERO)
Contact Us
Print
Feedback
Export to File
Search:
This record has one attached file:
Add More Files
Attach File(s):
Display Name for File*:
Save
Citation
Tags
HERO ID
3860779
Reference Type
Journal Article
Title
Estimated pKa values for the environmentally relevant C1 through C8 perfluorinated sulfonic acid isomers
Author(s)
Rayne, S; Forest, K
Year
2016
Is Peer Reviewed?
1
Journal
Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances & Environmental Engineering
ISSN:
1093-4529
EISSN:
1532-4117
Volume
51
Issue
12
Page Numbers
1018-1023
Language
English
PMID
27389973
DOI
10.1080/10934529.2016.1198191
Web of Science Id
WOS:000383030300004
Abstract
In order to estimate isomer-specific acidity constants (pKa) for the perfluorinated sulfonic acid (PFSA) environmental contaminants, the parameterization method 6 (PM6) pKa prediction method was extensively validated against a wide range of carbon oxyacids and related sulfonic/sulfinic acids. Excellent pKa prediction performance was observed for the carbon oxyacids using the PM6 method, but this approach was found to have a severe positive bias for sulfonic/sulfinic acids. To overcome this obstacle, a correlation was developed between non-adjusted PM6 pKa values and the corresponding experimentally obtained/estimated acidity constants for a range of representative alkyl, aryl and halogen-substituted sulfonic acids. Application of this correction to the PM6 values allows for extension of this computational method to a new acid functional group. When used to estimate isomer-specific pKa values for the C1 through C8 PFSAs, the modified PM6 approach suggests an adjusted pKa range from -5.3 to -9.0, indicating that all members of this class of well-known environmental contaminants will be effectively completely dissociated in aquatic systems.
Tags
PFAS
•
5:3 acid
Literature Search
Pubmed
WOS
Screening Results
Excluded/Not on Topic
•
^Per- and Polyfluoroalkyl Substances (PFAS)
5:3 acid (914637-49-3)
Literature Search
Pubmed
WOS
Home
Learn about HERO
Using HERO
Search HERO
Projects in HERO
Risk Assessment
Transparency & Integrity