Electrochemical process for producing ionic liquids

1. A process for preparing an ionic liquid in an electrochemical cell which comprises an anode and a cathode, the process comprises:

(1) charging the cell with a first solution comprising the desired cation for the ionic liquid to be produced and a second solution comprising the desired anion for the ionic liquid to be produced;

(2) subjecting the cell to electrolysis to produce the desired ionic liquid in solution; and

(3) recovering the desired ionic liquid from the solution.

2. The process of claim 1 wherein the first solution comprises an aqueous solution of an onium sail.

3. The process of claim 2 wherein the onium salt comprises a cation selected from the group consisting of substituted or unsubstituted ammonium, phosphonium, and sulfonium.

4. The process of claim 3 wherein the cation is selected from the group consisting of substituted or unsubstituted pyridinium, pyridazinium pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, imidazolinium, methylpyrrolidinium, isothiazolium, isoxazolium, oxazolium, pyrrolium, and thiophenium.

5. The process of claim 3 wherein the cation is an ammonium cation substituted by one more groups selected from the group consisting of alkyl and aryl groups.

6. The process of claim 2 wherein the onium salt comprises an anion selected from the group consisting of halide, hydroxide, formate, alkyl sulfate, triflate, triflouroacetate, perflouroalkylcarboxylate, perflouroalkylsulfonate, and methylcarbonate.

7. The process of claim 1 wherein the second solution is an aqueous solution.

8. The process of claim 7 wherein the aqueous solution is selected from the group consisting of organic salts, inorganic salts, organic acids, and inorganic acids.

9. The process of claim 8 wherein the aqueous solution is selected from the group consisting of acetic acid, nitric acid, and salts thereof.

10. The process of claim 1 wherein the ionic liquid is a hydrophilic ionic liquid.

11. The process of claim 1 wherein the ionic liquid is recovered from the ionic liquid in solution by evaporation, reverse osmosis, pervaporization, crystallization, distillation, azeotropic, and drying agents.

12. The process of claim 11 wherein the ionic liquid is recovered from the ionic liquid in solution by evaporation.

13. The process of claim 1 wherein the electrochemical cell is divided into two or more compartments by a means for dividing.

14. The process of claim 13 wherein the means for dividing is selected from the group consisting of a membrane, a nanoporous material, a diaphragm, and asbestos.

15. The process of claim 14 wherein the membrane is selected from the group consisting of a cation-exchange membrane, an anion exchange membrane, and a bipolar membrane.

16. The process of claim 1 wherein a gaseous by-product is produced.

17. The process of claim 16 wherein the gaseous by-product is hydrogen, ammonia, carbon dioxide, or nitrogen.

18. The process of claim 1 wherein the ionic liquid recovered from the solution comprises the desired cation and the desired anion.

19. A process for preparing an ionic liquid in an electrochemical cell which comprises an anode and a cathode, the process comprises:

(1) charging the cell with a first solution comprising the desired cation for the ionic liquid to be produced and a second solution comprising the desired anion for the ionic liquid to be produced;

(2) subjecting the cell to electrolysis to produce the desired ionic liquid in solution; and

(3) recovering the ionic liquid,

wherein the hydrophilic ionic liquid is selected from the group consisting of BMIM acetate, BMIM nitrate, and BMIM triflate.

20. A process for preparing an ionic liquid in an electrochemical cell which comprises an anode and a cathode, the process comprises:

(1) charging the cell with (a) a first solution that when subjected to electrolysis produces the desired cation for the ionic liquid to be produced and (b) a second solution that when subjected to electrolysis produces the desired anion for the ionic liquid to be produced;

(2) subjecting the cell to electrolysis to produce the desired ionic liquid in solution; and

(3) recovering the desired ionic liquid from the solution.

21. The process of claim 20 wherein the desired cation for the ionic liquid to be produced comprises an onium cation.

22. The process of claim 21 wherein the onium cation is selected from the group consisting of substituted or unsubstituted ammonium, phosphonium, and sulfonium.

23. The process of claim 22 wherein the cation is selected from the group consisting of substituted or unsubstituted pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, imidazolinium, methylpyrrolidinium, isothiazolium, isoxazolium, oxazolium, pyrrolium, and thiophenium.

24. The process of claim 20 wherein the second solution is an aqueous solution selected from the group consisting of organic salts, inorganic salts, organic acids, and inorganic acids.

25. The process of claim 20 wherein the ionic liquid is a hydrophilic ionic liquid.

26. The process of claim 20 wherein a gaseous by-product is produced.

27. The process of claim 20 wherein the ionic liquid recovered from the solution comprises the desired cation and the desired anion.

28. A process for preparing an ionic liquid in an electrochemical cell which comprises an anode and a cathode, the process comprises:

(1) charging the cell with (a) a first solution comprising the desired cation for the ionic liquid to be produced and (b) a second solution that when subjected to electrolysis produces the desired anion for the ionic liquid to be produced;

(2) subjecting the cell to electrolysis to produce the desired ionic liquid in solution; and

(3) recovering the desired ionic liquid from the solution.

29. The process of claim 28 wherein the desired cation for the ionic liquid to be produced comprises an onium cation.

30. The process of claim 29 wherein the onium cation is selected from the group consisting of substituted or unsubstituted ammonium, phosphonium, and sulfonium.

31. The process of claim 30 wherein the cation is selected from the group consisting of substituted or unsubstituted pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, imidazolinium, methylpyrrolidinium, isothiazolium, isoxazolium, oxazolium, pyrrolium, and thiophenium.

32. The process of claim 28 wherein the second solution is an aqueous solution selected from the group consisting of organic salts, inorganic salts, organic acids, and inorganic acids.

33. The process of claim 28 wherein the ionic liquid is a hydrophilic ionic liquid.

34. The process of claim 28 wherein a gaseous by-product is produced.

35. The process of claim 28 wherein the ionic liquid recovered from the solution comprises the desired cation and the desired anion.

36. A process for preparing an ionic liquid in an electrochemical cell which comprises an anode and a cathode, the process comprises:

(1) charging the cell with (a) a first solution that when subjected to electrolysis produces the desired cation for the ionic liquid to be produced and (b) a second solution comprising the desired anion for the ionic liquid to be produced;

(2) subjecting the cell to electrolysis to produce the desired ionic liquid in solution; and

(3) recovering the desired ionic liquid from the solution.

37. The process of claim 36 wherein the desired cation for the ionic liquid to be produced comprises an onium cation.

38. The process of claim 37 wherein the onium cation is selected from the group consisting of substituted or unsubstituted ammonium, phosphonium, and sulfonium.

39. The process of claim 38 wherein the cation is selected from the group consisting of substituted or unsubstituted pyridinium, pyridazinium, pyrimidinium, pyrazinium, imidazolium, pyrazolium, thiazolium, oxazolium, triazolium, imidazolinium, methylpyrrolidinium, isothiazolium, isoxazolium, oxazolium, pyrrolium, and thiophenium.

40. The process of claim 36 wherein the second solution is an aqueous solution selected from the group consisting of organic salts, inorganic salts, organic acids, and inorganic acids.

41. The process of claim 36 wherein the ionic liquid is a hydrophilic ionic liquid.

42. The process of claim 36 wherein a gaseous by-product is produced.

43. The process of claim 36 wherein the ionic liquid recovered from the solution comprises the desired cation and the desired anion.

44. A process for preparing an ionic liquid, the process comprises:

(1) producing a precursor solution to the ionic liquid in an electrochemical cell;

(2) converting the precursor solution to a solution of the desired ionic liquid in the electrochemical cell; and

(3) recovering the desired ionic liquid from the solution.

45. The process of claim 44 wherein the precursor solution comprises anions selected from the group consisting of hydroxide, carbonate, bicarbonate, acetate, and formate.

46. The process of claim 44 wherein the conversion comprises employing an acid.

47. The process of claim 46 wherein the acid is selected from the group consisting of acetic, nitric, triflic, methanesulfonic, and sulfuric.

48. The process of claim 44 wherein the desired ionic liquid recovered from the solution comprises a desired cation and a desired anion.