Effect of Water on the Extraction and Reactions of Fluoride Anion by Quaternary Ammonium Phase-Transfer Catalysts

Article abstract of DOI:10.1021/jo00206a031

The maximum conversion of the fluoride-chloride exchange reaction RCl + KF -> RF + KCl catalyzed by quaternary onium salts was found to be strongly dependent on the water content of the inorganic salt.A maximum conversion was obtained when the potassium fluoride contained 0.33 mol of water per mol of KF.This phenomenon is due to better extraction of the fluoride anion when the KF is drier, offset by decomposition of the catalyst in the absence of water.It was shown that the selectivity constant K^sel_Cl/F is dependent on composition of the inorganic salt and on temperature.Rate measurements indicate that the mechanism proposed by Starks for liquid-liquid exchange reactions is valid also in a solid-liquid process which is also chemically controlled.