Color-stable, low impurity tocopherol compositions and processes for preparing the same

1. A process for producing a color-stable, low-impurity tocopherol compound or mixture of tocopherol compounds comprising:

(a) providing a protecting group-substituted tocopherol compound;

(b) purifying the protecting group-substituted tocopharol compound by crystallizing it from a crystallization solvent and collecting the crystallized compound; and

(c) solvolyzing ibe purified compound to form free tocopherol.

2. The process according to claim 1 , wherein the solvolyzing is carried out under an inert atmosphere.

3. The process according to claim 2 , wherein the inert atmosphere comprises rntrogen.

4. The process according to claim 1 , wherein the protecting group-substituted tocopherol compound is an ester.

5. The process according to claim 4 , wherein the ester is selected from the group consisting of an acetate, a succinate, a phosphate, a phosphinate, a sulfonate and a carbonate.

6. The process according to claim 4 , wherein the ester is selected from the group consisting of an acetate and a succinate.

7. The process according to claim 4 , wherein the ester is an acetate.

8. The process according to claim 1 , wherein the tocopherol compound comprises α-tocopherol.

9. The process according to claim 8 , wherein the α-tocopherol is present in an amount of at least about 80% by weight based on the total tocopherol content.

10. The process according to claim 1 , wherein the tocopherol compound comprises d-α-tocopherol.

11. The process according to claim 10 , wherein the d-α-tocopherol is present in an amount of at least about 80% by weight based on the total tocopherol content.

12. The process according to claim 1 , wherein the tocopherol compound is a natural-source tocopherol.

13. . The process according to claim 12 , wherein the protecting group-substituted tocopherol compound is an ester.

14. The process according to claim 13 , wherein the ester is selected from the group consisting of an acetate and a succinate.

15. The process according to claim 13 , wherein the ester is an acetate.

16. The process according to claim 1 , wherein collecting the crystallized compound is by filtration.

17. The process according to claim 1 , wherein the crystallization solvent comprises a lower alcohol.

18. The process according to claim 1 , wherein the crystallization solvent comprises isopropanol.

19. The process according to claim 1 , wherein crystallizing the compound is carried out at a temperature below room temperature and above the freezing point of the crystallization solvent.

20. The process according to claim 1 , wherein the crystallization solvent comprises isopropanol and crystallizing the compound is carried out at a temperature of from about 10° C. to about -50° C.

21. The process according to claim 1 , further comprising re-mixing the crystallized compound with the crystallization solvent and repeating the crystallizing and the collecting at least once in sequential order.

22. The process according to claim 1 , wherein the protecting group-substituted tocopherol compound is an ester, and wherein solvolyzing the ester comprises a reaction selected from the group consisting of acid-catalyzed hydrolysis and base-promoted hydrolysis.

23. The process according to claim 1 , wherein the protecting group-substituted tocopherol compound is an ester, and wherein solvolyzing the ester comprises base-promoted hydrolysis.

24. The process according to claim 23 , wherein solvolyzing the ester comprises reacting the ester with an aqueous solution of a basic compound selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxide, ammonium hydroxide, and metal hydrides.

25. The process according to claim 24 , wherein the basic compound comprises an alkali metal hydroxide.

26. The process according to claim 24 , wherein the basic compound comprises sodium hydroxide.

27. The process according to claim 23 , wherein the hydrolysis is carried out in the presence of an alcohol solvent.

28. The process according to claim 27 , wherein the alcohol solvent comprises isopropanol.

29. The process according to claim 23 , wherein the hydrolysis is carried out in the presence of a reducing agent.

30. The process according to claim 29 , wherein the reducing agent comprises sodium borohydride.

31. The process according to claim 15 , wherein the hydrolysis is carried out under reflux conditions.

32. A process for producing a color-stable, low-impurity tocopherol compound or mixture of tocopherol compounds, said process comprising:

(a) providing an acetate of a natural-source tocopherol compound;

(b) crystallizing the acetate of the tocopherol compound from a solvent comprising isopropanol and collecting a purified acetate of the tocopherol compound; and

(c) reacting the purified acetate with an aqueous solution of sodium hydroxide in isopropanol under a nitrogen atmosphere at reflux conditions to form free tocopherol, in the presence of a reducing agent comprising sodium borohydride.

33. A process for purifying a tocopherol, said process comprising:

(a) providing a starting material comprising a tocopherol compound;

(b) reacting the starting material with a protecting group to form a reaction mixture comprising a protecting group-substituted tocopherol compound;

(c) separating the protecting group-substituted tocopherol compound from the reaction mixture to form a purified protecting group-substituted tocopherol compound; and

(d) solvolyzing the purified compound in the presence of a reducing agent to form a free tocopherol.

34. A process for purifying a tocopherol, said process comprising:

(a) providing an ester of a tocopherol compound,

(b) reacting the ester with an aqueous solution of a basic compound in an alcohol solvent under an inert atmosphere to form free tocopherol, in the presence of a reducing agent.

35. A composition comprising a natural tocopherol compound, wherein the composition has a color-stability such that the composition has a Gardner color value of less than about 6 after 24 hours at a temperature of up to about 60° C.

36. A composition comprising a color-stable, natural tocopherol compound, wherein the composition has an l-tocopherol content less than about 0.75% and a total non-α- tocopherol content of less than about 2%.