Extractive methods for purifying sucralose

• US 20030171574A1
• Filed: 03/08/2002
• Published: 09/11/2003
• Est. Priority Date: 03/08/2002
• Status: Active Grant

• Current Assignee: Tate & Lyle Technology Limited (TATE & LYLE PLC)
• Original Assignee: TATE & LYLE PLC
• Inventors: Micinski, Edward, Catani, Steven J., Vernon, Nicholas M., Wiley, James Edwin Jr., Neiditch, David Saul
• Granted Patent: US 7,049,435 B2
• Time in Patent Office: Days
• US Class Current: 536/119
• CPC Class Codes: C07H 1/06 Separation; Purification
• CPC Class Codes: C07H 5/02 to halogen

Abstract

The present invention relates to novel extractive methods for purifying sucralose. The present invention also relates to compositions comprising the sucralose preparations made by the methods of the present invention.

Claims

1. A method for removing impurities from a composition comprising sucralose and impurities comprising the steps of:

(a) performing a first liquid extraction of said composition comprising sucralose and impurities in a first solvent with a second at least partially immiscible solvent to effect removal of the impurities into said second solvent; and

(b) performing a second liquid extraction of said composition comprising sucralose and impurities in a first solvent with a third at least partially immiscible solvent to effect the transfer of the sucralose into said third solvent and the retention of the impurities in said first solvent.

2. The method of claim 1, wherein said step (a) effects removal of at least a portion of said impurities into said second solvent.

3. The method of claim 1, wherein said step (b) effects the transfer of the majority of the sucralose into said third solvent and the retention of a substantial portion of the impurities in said first solvent.

4. The method of claim 1, further comprising the step of recovering said sucralose.

5. The method of claim 4, wherein said recovering step comprises crystallizing said sucralose.

6. The method of claim 1, wherein said first solvent comprises water.

7. The method of claim 1, wherein said second solvent comprises ethyl acetate.

8. The method of claim 1, wherein said third solvent comprises ethyl acetate.

9. The method of claim 1, wherein the ratio of said second solvent to said first solvent is about 1:

2 to about 1;

5.

10. The method of claim 9, wherein said ratio is about 1:

3 to about 1;

4.

11. The method of claim 1, wherein said performing steps comprise a method of extraction selected from the group consisting of batch extraction, continuous extraction, and continuous countercurrent extraction.

12. The method of claim 1, further comprising the steps of recovering said second solvent after extraction of said first solvent, backwashing said second solvent with a new portion of said first solvent, and combining at least part of said new portion with the composition comprising sucralose and impurities in a first solvent prior to its extraction with said third solvent in step (b).

49. A sucralose preparation obtained by the method of claim 1.

13. A method for removing impurities from a composition comprising an aqueous solution of sucralose and impurities comprising the steps of:

(a) performing a first liquid extraction of said composition comprising an aqueous solution of sucralose and impurities with an at least partially immiscible non-aromatic organic solvent to effect removal of the impurities into said solvent; and

(b) performing a second liquid extraction of said composition comprising an aqueous solution of sucralose and impurities with an organic solvent to effect the transfer of the sucralose into said solvent and the retention of the impurities in the aqueous phase.

14. The method of claim 13, wherein said step (a) effects removal of at least a portion of said impurities into said solvent of step (a).

15. The method of claim 13, wherein said step (b) effects the transfer of the majority of the sucralose into said solvent of step (b) and the retention of a substantial portion of the impurities in the aqueous phase.

16. The method of claim 13, further comprising the step of recovering said sucralose.

17. The method of claim 16, wherein said recovering step comprises crystallizing said sucralose.

18. The method of claim 13, wherein said solvent utilized in step (a) is ethyl acetate.

19. The method of claim 13, wherein said solvent utilized in step (b) is ethyl acetate.

20. The method of claim 13, wherein the ratios of said solvents to the aqueous phase are about 1:

2 to about 1;

5.

21. The method of claim 20, wherein said ratios are about 1:

3 to about 1;

4.

22. The method of claim 13, wherein said performing steps comprise a method of extraction selected from the group consisting of batch extraction, continuous extraction, and continuous countercurrent extraction.

50. A sucralose preparation obtained by the method of claim 13.

23. A method for removing impurities from a composition comprising an aqueous solution of sucralose and impurities comprising the steps of:

(a) performing a first liquid extraction of said composition comprising an aqueous solution of sucralose and impurities with an at least partially immiscible organic solvent to effect the transfer of the impurities into said solvent;

(b) performing a second liquid extraction of said composition comprising an aqueous solution of sucralose and impurities with an organic solvent to effect the transfer of the sucralose into said solvent and the retention of the impurities in the aqueous phase;

(c) extracting the organic solvent remaining from step (a) with an aqueous solution to effect the transfer of the sucralose present in the organic phase into the aqueous solution; and

(d) combining the aqueous solution so obtained in step (c) with the aqueous solution recovered in step (a) prior to repeating step (b).

24. The method of claim 23, wherein said step (a) effects removal of at least a portion of said impurities into said solvent of step (a).

25. The method of claim 23, wherein said step (b) effects the transfer of the majority of the sucralose into said solvent of step (b) and the retention of a substantial portion of the impurities in the aqueous phase.

26. The method of claim 23, wherein said step (c) effects the transfer of a substantial portion of the sucralose present in the organic phase into the aqueous solution.

27. The method of claim 23, further comprising the step of recovering said sucralose.

28. The method of claim 27, wherein said recovering step comprises crystallizing said sucralose.

29. The method of claim 23, wherein said solvent utilized in step (a) is ethyl acetate.

30. The method of claim 23, wherein said solvent utilized in step (b) is ethyl acetate.

31. The method of claim 23, wherein said performing steps comprise a method of extraction selected from the group consisting of batch extraction, continuous extraction, and continuous countercurrent extraction.

32. The method of claim 23, wherein said extracting step comprises a method of extraction selected from the group consisting of batch extraction, continuous extraction, and continuous countercurrent extraction.

51. A sucralose preparation obtained by the method of claim 23.

33. A method for removing tetrachlorosucrose compounds from a solution of sucralose and chlorinated sucrose derivatives in a first solvent comprising extracting the solution of sucralose and other chlorinated sucralose derivatives with an at least partially immiscible non-aromatic second solvent to effect the partition of the tetrachlorosucrose compounds into said second solvent and the retention of the sucralose in said first solvent.

34. The method of claim 33, wherein said method effects the partition of a majority of the tetrachlorosucrose compounds into said second solvent and the retention of a majority of the sucralose in said first solvent.

35. The method of claim 33, wherein said tetrachlorosucrose compounds are selected from the group consisting of 4,1′

,4′

,6′

-tetrachlorogalactotagatose and 4,6,1′

,6′

-tetragalactosucrose.

36. The method of claim 33, wherein said extracting step comprises a method of extraction selected from the group consisting of batch extraction, continuous extraction, and continuous countercurrent extraction.

52. A sucralose preparation obtained by the method of claim 33.

37. A method for removing impurities from a composition comprising a solution of sucralose and impurities in a first solvent comprising the steps of:

(a) performing a first liquid extraction of said composition comprising a solution of sucralose and impurities in a first solvent with a second solvent that possesses a lower Hildebrand parameter than said first solvent under conditions that selectively transfer impurities less polar than sucralose into said second solvent thereby providing a sucralose solution in said first solvent that has an increased ratio of sucralose to impurities less polar than sucralose; and

(b) performing a second liquid extraction of said composition comprising a solution of sucralose and impurities in a first solvent with a third solvent that possesses a higher Hildebrand parameter than said first solvent under conditions that selectively transfer impurities more polar than sucralose into said third solvent thereby providing a sucralose solution in said first solvent with an increased ratio of sucralose to impurities more polar than sucralose.

38. The method of claim 37, further comprising the step of recovering said sucralose.

39. The method of claim 38, wherein said recovering step comprises crystallizing said sucralose.

40. The method of claim 37, wherein the ratio of said second solvent to said first solvent is about 1:

2 to about 1;

5.

41. The method of claim 40, wherein said ratio is about 1:

3 to about 1;

4.

42. The method of claim 37, wherein said performing steps comprise a method of extraction selected from the group consisting of batch extraction, continuous extraction, and continuous countercurrent extraction.

53. A sucralose preparation obtained by the method of claim 37.

43. A method for removing impurities from a composition comprising a solution of sucralose and impurities in a first solvent comprising the steps of:

(a) performing a first liquid extraction of said composition comprising a solution of sucralose and impurities in a first solvent with a second solvent that possesses a higher Hildebrand parameter than said first solvent under conditions that selectively transfer sucralose into said second solvent thereby providing a sucralose solution in said second solvent that has an increased ratio of sucralose to impurities less polar than sucralose; and

(b) performing a second liquid extraction of said sucralose solution in said second solvent obtained in the previous step with a third solvent that possesses a higher Hildebrand parameter than said second solvent under conditions that selectively transfer impurities more polar than sucralose into said third solvent thereby providing a sucralose solution in said second solvent that has an increased ratio of sucralose to impurities more polar than sucralose.

44. The method of claim 43, further comprising the step of recovering said sucralose.

45. The method of claim 44, wherein said recovering step comprises crystallizing said sucralose.

46. The method of claim 43, wherein the ratio of said second solvent to said first solvent is about 2:

1 to about 5;

1.

47. The method of claim 46, wherein said ratio is about 3:

1 to about 4;

1.

48. The method of claim 43, wherein said performing steps comprise a method of extraction selected from the group consisting of batch extraction, continuous extraction, and continuous countercurrent extraction.

54. A sucralose preparation obtained by the method of claim 43.