Regeneration of onium fluoride-HF adducts

In a process for producing fluorine-containing compounds from chlorine-containing or bromine-containing compounds by chlorine-fluorine exchange or bromine-fluorine exchange using an onium fluoride-HF adduct as a reagent or catalyst, the improvement comprising regenerating spent onium fluoride-HF adduct using HF in the presence of a liquid carboxylic acid;

• or regenerating a spent trialklyammonium fluoride-HF adduct or a spent HF adduct of a cyclic saturated amine using HF.