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FRD-903 3D BS.png
Preferred IUPAC name
2,3,3,3-Tetrafluoro-2-(heptafluoropropoxy)propanoic acid
Other names
Perfluoro-2-propoxypropanoic acid, hexafluoropropylene oxide dimer acid (HFPO-DA)
3D model (JSmol)
ECHA InfoCard 100.032.928 Edit this at Wikidata
EC Number
  • 236-236-8
  • InChI=1S/C6HF11O3/c7-2(1(18)19,4(10,11)12)20-6(16,17)3(8,9)5(13,14)15/h(H,18,19)
  • C(=O)(C(C(F)(F)F)(OC(C(C(F)(F)F)(F)F)(F)F)F)O
Molar mass 330.053 g·mol−1
Acidity (pKa) 3.82
GHS labelling:
H302, H314, H335
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

FRD-903 (also known as hexafluoropropylene oxide dimer acid, HFPO-DA, and 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoic acid) is a chemical compound that is among the class of per- and polyfluoroalkyl substances (PFASs). More specifically, this synthetic petrochemical is also described as a perfluoroalkyl ether carboxylic acid (PFECA).[1] It is not biodegradable and is not hydrolyzed by water.[2][3]


The ammonium salt of FRD-903 is FRD-902 (ammonium (2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate)), which is the specific chemical which Chemours has trademarked as part of GenX process.

Drinking water[edit]

In 2020 Michigan adopted drinking water standards for 5 previously unregulated PFAS compounds including HFPO-DA which has a maximum contaminant level (MCL) of 370 parts per trillion (ppt).[4][5]


  1. ^ "Gen-x/PFAS Information". Brunswick County, North Carolina. Retrieved 11 December 2021.
  2. ^ "Justification for the selection of a substance for CoRAP inclusion". Retrieved 23 July 2017.
  3. ^ Beekman, M.; et al. (2016-12-12). "Evaluation of substances used in the GenX technology by Chemours, Dordrecht". National Institute for Public Health and the Environment (RIVM, The Netherlands). Retrieved 2017-07-23.
  4. ^ Matheny, Keith (3 August 2020). "Michigan's drinking water standards for these chemicals now among toughest in nation". Detroit Free Press. Archived from the original on 31 January 2022. Retrieved 31 March 2022.
  5. ^ "New state drinking water standards pave way for expansion of Michigan's PFAS clean-up efforts". 3 August 2020. Archived from the original on 3 January 2022. Retrieved 5 April 2022.