Dynamic Phase Behavior of Surface-Active Fluorinated Ionic Liquid Epoxidation Catalysts

We report on the synthesis of amphiphobic fluorinated surface-active ionic liquid (FSAIL) epoxidation catalysts, which show reversible temperature-controlled solubility in water. The solubility of FSAILs containing the catalytically active perrhenate- and tungstate anions was studied in both the aqueous and the substrate phase, showing a significant solubility decrease in both media compared to their non-fluorinated congeners. It was shown that both the epoxide product and the catalyst additive phenylphosphonic acid (PPA) are efficient in transferring the FSAIL catalyst into the organic phase, rendering the reaction homogeneous. The FSAILs were used as catalysts for the epoxidation of olefins using aqueous H₂O₂ as oxidant, showing an exceptionally high catalytic activity at mild conditions. Catalyst recycling was demonstrated over ten consecutive runs by phase separation and subsequent product distillation.