Perfluoropropionic acid

Perfluoropropionic acid (PFPrA) or pentafluoropropionic acid is an ultra-short chain perfluoroalkyl carboxylic acid with the formula CF₃CF₂CO₂H. It is a colorless liquid that is strongly acidic. It soluble in both water and polar organic solvents. The compound is produced by electrochemical fluorination of the carboxylic acid or its acid fluoride derivative.^[3]

Perfluoropropionic acid

Names
Other names pentafluoropropionic acid perfluoropropanoic acid PFPrA C3 PFCA[1]
Identifiers
CAS Number	422-64-0
3D model (JSmol)	Interactive image
ChemSpider	56147
ECHA InfoCard	100.006.384
EC Number	207-021-6
PubChem CID	62356
CompTox Dashboard (EPA)	DTXSID3097848 DTXSID8059970, DTXSID3097848
InChI InChI=1S/C3HF5O2/c4-2(5,1(9)10)3(6,7)8/h(H,9,10) Key: LRMSQVBRUNSOJL-UHFFFAOYSA-N
SMILES C(=O)(C(C(F)(F)F)(F)F)O
Properties
Chemical formula	C3HF5O2
Molar mass	164.031 g·mol−1
Appearance	colorless liquid
Density	1.561 g/mL
Boiling point	96–97 °C (205–207 °F; 369–370 K)
Acidity (pKa)	0.38±0.10
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	corrosive
GHS labelling:[2]
Pictograms
Signal word	Danger
Hazard statements	H314, H332
Precautionary statements	P280, P301+P330+P331, P305+P351+P338, P310
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

It has a predicted pK_a of 0.38, with an uncertainty of 0.10.^[4] In many ways, it is comparable to trifluoroacetic acid.

Occurrence and use

The perfluoropropanoate form has been found in environmental samples.^[5]

A convenient laboratory method for generating tetrafluoroethylene is the pyrolysis of the sodium salt of pentafluoropropionic acid:^[6]

C₂F₅CO₂Na → C₂F₄ + CO₂ + NaF