Annealing protocols for pyrrolidinium bis(trifluoromethylsulfonyl)imide type ionic liquids

The phase transitions in ionic liquids (ILs) of the N-alkyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR1ATFSI) family show a common pattern, which implies a typical and characteristic crystal packing. Many of these features are also observed for the N-alkyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide (PIP1ATFSI) family. Here we report the thermal behavior of some ILs of the PYR1ATFSI and PIP1ATFSI families and a few others having different anions. The thermal history was found to decide which phases will appear and, therefore, specific protocols were defined to obtain the desired phases in a reasonable amount of time.