Synthesis of ionic liquids
Ionic compounds which are liquids at room temperature are formed by the method of mixing a neutral organic liqand with the salt of a metal cation and its conjugate anion. The liquids are hydrophobic, conductive and stable and have uses as solvents and in electrochemical devices.
1. A liquid ionic compound comprising a cation which is a complex of a neutral ligand selected from the group consisting of alkyl amines and crown ethers with a metal ion selected from the group consisting of Na + , K + , Li + , Ca 2+ , Ag + , Zn 2+ , Cu 2+ , Cd 2+ , Ni 2+ , Hg 2+ , Co 3+ and Fe 3+ and an anion which is a conjugate anion of the metal ion, wherein said anion comprises sulfur or phosphorous.
2. An ionic compound according to claim 1 which is a liquid below 100°C.
3. An ionic compound according to claim 2 which is a liquid at room temperature.
4. An ionic compound according to claim 1 which is electrically conductive in the absence of a solvent.
5. An ionic liquid according to claim 1 which is hydrophobic.
6. An ionic compound according to claim 1 wherein said neutral organic ligand is a crown ether.
7. An ionic compound according to claim 1 wherein said conjugate anion is bis(trifluoromethane)sulfonimide, boron trifluoride, nitrate, sulfate, phosphate, hexafluorophosphate and dicyananiide.
8. A method for forming a liquid ionic compound, the method comprising mixing a neutral ligand selected from the group consisting of organic alkyl amines and crown ethers with a metal ion selected from the group consisting of Na + , K + , Li + , Ca 2+ , Ag + , Zn 2+ , Cu 2+ , Cd 2+ , Ni 2− , Hg 2+ , Co 3+ and Fe 3+ and with the salt of a metal cation and its conjugate anion at room temperature.
9. A method according to claim 8 wherein said neutral organic ligand is a crown ether.
10. A method according to claim 9 wherein the metal cation is selected from the group consisting of sodium, potassium, lithium and calcium.
11. A method according to claim 8 wherein said metal cation is selected from the group consisting of silver, zinc, copper, cadmium, nickel, mercury and iron.
12. A method according to claim 8 wherein said conjugate anion is bis(trifluoromethane)sulfonimide, boron trifluoride, nitrate, sulfate, phosphate, hexafluorophosphate and dicyanamide.