Fluorous protic ionic liquids exhibit discrete segregated nano-scale solvent domains and form new populations of nano-scale objects upon primary alcohol addition

Abstract

Fluorous protic ionic liquids (FPILS) containing a perfluorinated anion and hydrocarbon cation have been observed to segregate into nano-scale fluorocarbon, hydrocarbon and polar domains. The solubility and interactions of ethanol and butanol in a series of FPILs has been investigated by synchrotron source small and wide angle X-ray scattering. Nano-scale objects were found to be present within the binary solutions from low concentrations of FPILs in alcohols to around 40 to 80 wt% FPIL. The FPILs retain their fluorocarbon, hydrocarbon and polar domains in binary mixtures with alcohols in addition to the formation of nano-scale alcohol associated objects. For comparison, the influence of alcohols on the nano-scale segregation of analogous protic ionic liquids (PILs) which contained hydrocarbon anions in place of the perfluorinated anions was also investigated. The ethanol and butanol were miscible with the PILs across the full concentration range, with no evidence for the formation of analogous nano-scale objects. The FPILs are prospective solvents which may enable simultaneous solubility of fluorocarbon, hydrocarbon and polar species.