N-methyl-N-alkylpyrrolidinium nonafluoro-1-butanesulfonate salts:: Ionic liquid properties and plastic crystal behaviour

A series of N-methyl-N-alkylpyrrolidinium nonafluoro-l-butanesulfonate salts were synthesised and characterised. The thermophysical characteristics of this family of salts have been investigated with respect to potential use as ionic liquids and solid electrolytes. N-Methyl-N-butylpyrrolidinium nonafluoro-l-butanesulfonate(p(1,4)NfO) has the lowest melting point of the family, at 94 degrees C, Electrochemical analysis of p(1,4) NfO in the liquid state shows an electrochemical window of similar to 6V. All compounds exhibit one or more solid-solid transitions at sub-ambient temperatures, indicating the existence of plastic crystal phases.