Ion‐exchange rate limitation on a polymer‐supported phase transfer catalytic reaction

Abstract

Abstract The ion‐exchange rate limitation on the kinetics of the series substitution reactions between hexachlorocyclotriphosphazene (NPCl 2 ) 3 and 2,2,2‐trifluoroethanol (HOCH 2 CF 3 ) by polystyrene‐bound tri‐ n ‐butylammonium ion in an organic solvent/alkaline solution was studied. It was found that the diffusional limitation involves both ion diffusion and organic reactant diffusion within the catalyst pellet. The displacement reaction rate of (NPCl 2 ) 3 in the organic phase was limited by the particle diffusion and the intrinsic reactivity together. The film diffusion in the bulk solution limited the rate of ion exchange. The mass transport of the ion‐exchange step in the aqueous phase was not improved by increasing the concentration of NaOCH 2 CF 3 . Drastic kinetic rate improvement was achieved with proper adjustment of the volume of the aqueous solution which was a low concentration of salt in the aqueous phase.