Perfluoropropionic acid (PFPrA) or pentafluoropropionic acid is an ultra-short chain perfluoroalkyl carboxylic acid with the formula CF<sub>3</sub>CF<sub>2</sub>CO<sub>2</sub>H. 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.
It has a predicted pK<sub>a</sub> of 0.38, with an uncertainty of 0.10. In many ways, it is comparable to trifluoroacetic acid.
The perfluoropropanoate form has been found in environmental samples.
A convenient laboratory method for generating tetrafluoroethylene is the pyrolysis of the sodium salt of pentafluoropropionic acid: