The several routes to acyl fluorides can be roughly subdivided into three approaches.
Halide exchange Acyl chlorides react with
hydrogen fluoride to give acyl fluorides. This reaction is relevant to the use of
electrofluorination route to
perfluorinated carboxylic acids, such as
PFOA.
S- and P-based reagents The OH group of carboxylic acids can be converted to fluoride using various oxophilic reagents. Aromatic (as well as aliphatic) acyl fluorides can be prepared from carboxylic acids with and fluoride sources.
Cyanuric fluoride as well as
sulfur tetrafluoride also convert carboxylic acids to acyl fluorides. :
Fluorophosgene Salts of trifluoromethoxide react with carboxylic acids to give acyl fluorides. The process entails formation of
difluorophosgene. Solutions of
trifluoromethoxide are prepared by displacement from aryl trifluoromethyl ethers. ==Reactions==