Phase Transfer Catalyzed Bromide—Chloride Exchange: Dependence of Equilibrium Position and Selectivity Constant on Nature and Composition of Aqueous Phase

The position of the equilibrium in the PTC exchange reaction of alkyl chloride with metal bromide salts RCl + MBr ⇌ RBr + MCI under various condtions is utilized for calculation of the selectivity constant K^sel_Cl/Br. This constant is found to be dependent on the nature of the metal cation and the inorganic phase composition. K^sel_Cl/Br can be defined for any point on the phase diagram MCl—MBr—H₂O at a given temperature, solvent and quaternary cation.