Quantitative Generation of HF from KF and Formation of Amine‐3HF Complexes by Using Cation Exchange Reaction Between KF and Amberlyst 15DRY

A safe and convenient method for the quantitative generation of hydrogen fluoride (HF) from potassium fluoride (KF) at room temperature was successfully demonstrated using the cation exchange reaction between KF and Amberlyst 15DRY in acetonitrile (MeCN). After one of the cation exchange reactions, HF was generated from KF in 69% yield. On the other hand, HF was generated quantitatively by removing the generated HF and repeating the cation exchange reaction seven times. During and after the cation exchange reaction, the generated HF was separated from the Amberlyst 15DRY by decantation and filtration without loss of HF. When the Amberlyst 15DRY was regenerated and then reused in the cation exchange reaction ten times, HF was generated almost quantitatively each time and the yield of HF did not decrease at all. In addition, when 1/3 equivalent of amines was added to the resulting HF-containing solution, a variety of amine-3HF complexes with controlled stoichiometric ratios were formed in quantitative yields.