4. Preparation of fluorinated products by chlorine-fluorine exchange

The exchange of a halogen atom other than fluorine (iodine, bromine, chlorine) by fluorine, using metal fluorides and/or hydrofluoric acid, is used in many processes for the manufacture of organic fluorinated products, both aliphatic (fluoro- and chlorofluoroalkanes...) and aromatic (aromatic derivatives with fluorinated side chains). Industrial processes only concern chlorine-fluorine exchanges, and we will not discuss exchanges of other halogens, which have only been put into practice in the laboratory.

Fluorination of chlorine derivatives with hydrofluoric acid is by far the most important method of preparing fluorine derivatives, but chlorine-fluorine exchange using metal fluorides is of great scientific interest. In fact, the fluorination of chlorine derivatives with antimony fluorides (SbF ₃ -SbCl _...