Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-08-03
2002-08-06
Owens, Amelia (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C549S407000, C549S408000, C552S547000
Reexamination Certificate
active
06429320
ABSTRACT:
BACKGROUND OF THE INVENTION
As concerns over maintaining proper health continue to grow, vitamin and antioxidant use and intake also continue to rise. As more evidence of the potential benefits associated with the use and intake of vitamins and antioxidants continues to be generated, demand for such substances increases, as does the demand for purer forms thereof. Many antioxidants and vitamins can be found in, and extracted from, natural sources. However, these natural sources, e.g., plants and vegetables, contain many undesirable components and impurities which are extracted along with the antioxidants.
For example, tocopherol compounds are components of vegetable oils which exhibit vitamin E activity. Tocopherol compounds are found widely distributed in many organic substances, including grain oils and vegetable oils. However, the amount of tocopherol present in the natural oils may be small, and therefore, the oils are distilled to concentrate the tocopherol content. Unfortunately, the content of other undesirable co-boilers, as well as pesticides, fertilizers, etc. may also be concentrated.
As such, there have been many attempts to recover and purify antioxidants, such as tocopherols, from natural sources. For example, a method which involves mixing a tocopherol-containing material with a polar organic solvent and contacting this mixture with a strongly basic anionic exchange resin, whereby the tocopherols are absorbed onto the resin, and subsequently eluted with an acidic solution, has been described. However, such methods can result in resin fouling, and potential oxidation of the resins may result in a persistent amine odor. Moreover, resins are short-lived, expensive and provide relatively low capacity.
Other processes for the isolation of tocopherols involve treating deodorizer distillates, which comprise the “sludge” or distillate obtained in connection with the production of edible oils and fats subsequent to the deodorization step, with a lower aliphatic alcohol in the presence of an acid catalyst, often with prior saponification of the sludge, for the purposes of esterifying the free fatty acids present in the sludge. Other processes have been disclosed wherein the tocopherols and/or sterols are esterified with the free fatty acids contained in the distillates. However, these processes are often complicated, time-consuming and expensive. Moreover, most prior art processes for the purification or isolation of tocopherols and/or sterols which involve the esterification of the tocopherols and/or sterols with free fatty acids present in the feed are incapable of adequately removing impurities and other components which co-distill with tocopherols and/or sterols, at sufficient yields.
Another process for the separation of tocopherols has been described wherein borate esters are formed, the mixture is distilled and the esters are subsequently hydrolyzed, with subsequent separation of the borate source from the tocopherol. While such a process generally removes a large portion of the impurities that co-distill with the tocopherol, significant amounts of the tocopherol in the original feed material can be lost during the purification, foaming during the esterification process is a significant problem, and undesirable borate solids can form requiring additional separation steps.
Thus, there is a need in the art for a process by which tocopherol and/or sterol compounds can be purified in high yield from natural sources with suitably high degrees of purity.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to processes for the purification of compounds, such as tocopherol and/or sterol compounds, from natural sources, wherein a high yield is obtained, in addition to a high degree of purity. The processes according to the present invention provide purified tocopherols and sterols from natural sources at unexpectedly high and significantly improved yields and further remove many of the unwanted components which co-distill with tocopherols and/or sterols, as well as impurities and other undesirable components to negligible amounts and even undetectable levels.
The present invention includes a process for purifying compounds, wherein the process comprises: (a) providing a first mixture comprising at least one compound selected from the group consisting of tocopherol compounds and sterol compounds, and an alcohol having from about 10 to about 30 carbon atoms; (b) reacting the first mixture with one or more boron-containing compounds selected from the group consisting of boric acid, alkoxy borates, alkoxy boroxines, phenoxy borates and phenoxy boroxines to form a second mixture comprising one or more orthoborate esters, wherein the mole ratio of combined tocopherol, sterol and alcohol to boron is at least about 2.5:1; (c) heating the second mixture to remove low boiling point components to form a residue comprising the one or more orthoborate esters; (d) contacting the residue with one or more compounds capable of solvolyzing the one or more orthoborate esters to form a third mixture comprising one or more resulting boron-containing compounds, the alcohol and the at least one compound selected from the group consisting of tocopherol compounds and sterol compounds; and (e) recovering the at least one compound selected from the group consisting of tocopherol compounds and sterol compounds.
In accordance with preferred embodiments of the present invention, the alcohol comprises oleyl alcohol or dodecyl alcohol, the boron-containing compound comprises boric acid, the mole ratio of combined tocopherol, sterol and alcohol to boron is at least about 3:1; and step (c) is carried out at a temperature which is about 60° C. greater than the boiling point of the at least one compound selected from the group consisting of tocopherol compounds and sterol compounds, under reduced pressure.
The present invention also includes a process for purifying compounds, said process comprising: (a) subjecting a composition comprising at least one compound selected from the group consisting of tocopherol compounds and sterol compounds to an activated carbon pretreatment; (b) combining the pretreated composition with one or more boron-containing compounds selected from the group consisting of boric acid, alkoxy borates, alkoxy boroxines, phenoxy borates and phenoxy boroxines to form a mixture comprising one or more borate esters; (c) heating the mixture to remove low boiling point components to form a residue comprising the one or more borate esters; (d) contacting the residue with one or more compounds capable of solvolyzing the one or more borate esters to form a second mixture comprising one or more resulting boron-containing compounds and the at least one compound selected from the group consisting of tocopherol compounds and sterol compounds; and (e) separating the one or more resulting boron-containing compounds and the at least one compound selected from the group consisting of tocopherol compounds and sterol compounds.
Furthermore, the present invention includes a composition comprising a mixture of trialkyl orthoborate esters, dialkyl-monotocopherol orthoborate esters, and monoalkyl-ditocopherol orthoborate esters. A composition in accordance with the present invention may further comprise dialkyl-monosterol orthoborate esters, monoalkyl-disterol orthoborate esters and monoalkyl-monotocopherol-monosterol orthoborate esters. Additionally, the present invention includes a composition prepared by a process comprising: (a) combining a composition comprising at least one compound selected from the group consisting of tocopherol compounds and sterol compounds with an alcohol having from about 10 to about 30 carbon atoms to form a first mixture; (b) reacting the first mixture with one or more boron-containing compounds selected from the group consisting of boric acid, alkoxy borates, alkoxy boroxines, phenoxy borates and phenoxy boroxines to form a second mixture comprising one or more orthoborate esters, wherein the mole ratio of combined tocopherol, sterol and alcohol to boron is at least ab
McCurry, Jr. Patrick M.
Pickens Carl
Turner Stephen W.
Varvil Jan R.
Cognis Corporation
Drach John E.
Ettelman Aaron R.
Owens Amelia
Varvil Jan R.
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