Abstract Acyl fluorides are usually prepared from the corresponding chlorides by halogen exchange. High temperatures are necessary with potassium fluoride (1). The use of potassium bifluoride (2), thallium fluoride (3) or amines-fluorhydric acid complexes (4, 5, 6) allowed the reaction to occur in milder conditions. Addition of fluoroketones (7) or ether- crowns (8) increased the activity of potassium fluoride.
