FRD-903

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) and a Fluorointermediate.^[2] It is not biodegradable and is not hydrolyzed by water.^[3][4]

FRD-903

Names
Preferred IUPAC name 2,3,3,3-Tetrafluoro-2-(heptafluoropropoxy)propanoic acid
Other names Perfluoro-2-propoxypropanoic acid, hexafluoropropylene oxide dimer acid (HFPO-DA), C3 dimer acid
Identifiers
CAS Number	13252-13-6
3D model (JSmol)	Interactive image
ECHA InfoCard	100.032.928
EC Number	236-236-8
PubChem CID	114481
CompTox Dashboard (EPA)	DTXSID70880215
InChI 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)
SMILES C(=O)(C(C(F)(F)F)(OC(C(C(F)(F)F)(F)F)(F)F)F)O
Properties
Chemical formula	C6HF11O3
Molar mass	330.053 g·mol−1
Appearance	Liquid <60 °C
Density	1.748 g/cm3 (at 20 °C)
Solubility in water	Soluble, 739 g/L [1]
Acidity (pKa)	3.82
Hazards
GHS labelling:
Hazard statements	H302, H314, H335
Hazards
GHS labelling:
Pictograms
NFPA 704 (fire diamond)	3 2 0
Flash point	60 °C (140 °F; 333 K)
Safety data sheet (SDS)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Production

The production process involves 2 molecules of hexafluoropropylene oxide (HFPO) to produce hexafluoropropylene oxide dimer acid fluoride (FRD-903). 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.^[5] FRD-903 is used as an aid within the manufacturing process for fluoropolymers by reducing the surface tension in the process, allowing polymer particles to increase in size. The process is completed with chemical treatment or heating to remove the FRD-903 from the final polymer product. It can then be recovered for re-use within the process.^[6]

Drinking water

In 2020, Michigan adopted drinking water standards for five previously unregulated PFAS compounds including HFPO-DA which has a maximum contaminant level (MCL) of 370 parts per trillion (ppt).^[7][8]

In March 2023, the EPA announced drinking water standards for several PFAS chemicals, which included FRD-903.^[9][10]

References

1. Drinking Water Health Advisory epa.gov
2. "Gen-x/PFAS Information". Brunswick County, North Carolina. Retrieved 11 December 2021.
3. "Justification for the selection of a substance for CoRAP inclusion". Retrieved 23 July 2017.
4. 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.
5. "GenX Chemical in Drinking Water: Side Effects and Health Risks of GenX". 13 November 2023.
6. "What is GenX? | Get the Facts".
7. 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.
8. "New state drinking water standards pave way for expansion of Michigan's PFAS clean-up efforts". Michigan.gov. 3 August 2020. Archived from the original on 3 January 2022. Retrieved 5 April 2022.
9. "EPA announces drinking water standards for six individual PFAS "forever chemicals"".
10. "EPA Proposes PFAS National Primary Drinking Water Rule -- hearing (5/4), invites comments (By 5/30) - EconSpark".