Of commercial interest, acyl chlorides react with HF to give acyl fluorides. Aromatic (as well as aliphatic) acyl fluorides are conveniently prepared directly from carboxylic acids, using stable, inexpensive commodity chemicals: , NBS and  in a bench-top protocol. Cyanuric fluoride converts carboxylic acids to acyl fluorides.
Carboxylic acids react with sulfur tetrafluoride to give the acyl fluoride: