Patent ID: 6852229

Claim:
A method for preparing a high-purity ionic liquid having a pH value of 7 and an elemental analysis deviation of less than 0.5 wt % between a calculated elemental analysis and a found elemental analysis for each of carbon, hydrogen and nitrogen, the method comprising forming a monophasic or biphasic mixture of an ionic liquid and an inert liquid, wherein the ionic liquid comprises a cationic species and an anionic species wherein the anionic species is selected from the group consisting of tetrafluoroborate, hexafluorophosphate, bis-trifluoromethanesulfonimide and derivatives thereof, wherein the biphasic mixture comprises an aqueous phase and an ionic liquid phase; and (a) when the monophasic mixture is formed: (i) filtering the monophasic mixture to yield a filtrate; and (ii) recovering the ionic liquid from the filtrate; and (b) when the biphasic mixture is formed: (i) separating the ionic liquid phase from the aqueous phase; (ii) filtering the ionic liquid phase to yield a filtrate; and (iii) recovering the ionic liquid from the filtrate.