US2433593A

US2433593A - Antioxidants and method of producing same

Info

Publication number: US2433593A
Application number: US510974A
Authority: US
Inventors: Loran O Buxton
Original assignee: Nopco Chemical Co
Current assignee: Nopco Chemical Co
Priority date: 1943-11-19
Filing date: 1943-11-19
Publication date: 1947-12-30
Anticipated expiration: 1964-12-30

Description

. oxidants heretofore produced.

Patented Dec. 30, 1 947 2,433,593 I C E ANTIOXIDANTS AND METHOD OF 3 PRODUCING SAME Lpran 0. Buxton, -Newark,- N. J., assignor to. Nopco Chemical Company, Harrison, N. J., a corporation of New Jersey No Drawing. Application November 19, 1943,

Serial No. 510,974!

18 Claims.

This invention relates to novel antioxidants derived from the soap stock or foots produced incidentally to the alkali refinement of vegetable oils, and to a method of producing these antioxidants.

Antioxidants have hitherto been derived from a wide variety of source materials and used as preservatives in a large number of oxidationsensitive organic substances 'such as vitamin preparations, foodstufis, oils, fats, lubricants, fuels, rubber compositions, etc. However, antioxidants are not of equal effectiveness in all substances, the action of any particular antioxidant in admixture with any particular oxidation-sensitive substance being peculiar to that particular combination of antioxidant and substance. Further, the source materials heretofore employed for the production of antioxidants are not always of low cost or ready availability. Accordingly, there exists a wide field for the introduction of novel antioxidants and for the discovery of new source materials therefor.

In the usual process of refining vegetable oils, the crude oils are preliminarily treated by means of alkali, followed by a separation of the resultant soap complex from the oil. The separated soap complex material is variously known as foots, soap stock and the like. Hereinafter, such materials will be designated soap stocks. It has not heretofore been realized that soap stocks contain substantial quantities of antioxidants or that they could be used as source materials for the production of antioxidants.

Accordingly, it is an object of this invention to provide novel antioxidants.

Another object is to provide antioxidants which will have a more effective action than anti- Another object is to employ, as source materials for antioxidants, the relatively plentiful and cheap soap stocks obtained in the alkali refinement of vegetable oils.

The foregoing and other objects are secured in accordance with this invention in a process which involves the extraction by means of non-polar solvents at relatively high temperatures of soap stocks obtained in the alkali refinement of vegetable oils. The solvent extract is separated from the soap stock, and the solvent removed from the extract, leaving a product which exerts a very effective antioxidant action when compounded with a wide variety of oxidation-susceptible pharmaceutical, food and industrial materials. The antioxidant extracts of this invention exert a particularly eifective action when used in conjunction with phosphatides, such as the lecithins, with which they appear to exert a synergistic eifect far in excess of the antioxidant power of either the antioxidant itself or the phosphatides.

The solvents employed in the extraction step of this invention may be any relatively low molecular weight, non-polar, water-immiscible, organic solvents which will not dissolve any appreciable quantity of the soaps in the soap stock complex to be treated. Such solvents are exemplified in hydrocarbon solvents such as hexane, heptane, cyclohexane, methyl cyclohexane, petroleum ether, naphtha and the like; or chlorinated hydrocarbon solvents such as ethylene dichloride,

trichlorethane, chloroform, carbon tetrachloride and the like. Mixtures of solvents above indicated as suitable may likewise be employed.

. Soap stocks suitable as source materials in the process of this invention may be any soap stocks conventionally produced in the alkali refinement of vegetable oils such as corn oil, peanut oil, linseed oil, coconut oil, soyabean oil, cottonseed oil,

sesame oil or the like. Instead of relying upon commercially produced soap stocks as source materials for the'antioxidants of this invention,

it would likewise be advantageous to carry out 4 an alkali refinement of a vegetable oil with a special view to providing a soap stock more suitable for use as a source material in this invention; for instance, the alkali treatment could be carried out in an inert atmosphere, or in the presence of reducing agents such as sodium sulfite, morpholine sulfite, and the like. In this case, in addition to the corn, etc. oils above named as being conventionally alkali refined, other oils providing special antioxidant products might be employed, such as corn germ oil, wheat germ oil, rice germ oil, fish liver oils, cranberry seed oil, and the like. In any case, the soap stock should be extracted in accordance with the invention as soon as possible after its production from the oil, and/or should be stored at low temperatures during the interval between production and utilization in this invention, since the soap stock at ordinary temperatures tends to deteriorate by fermentation, hydrolysis of the soaps, and destruction of the antioxidant principles therein.

Alkali refinement of vegetable oils is highly conventional and need not be further discussed herein beyond pointing out the principal types of such refinement, viz. (a), processes in which the crude oil is contacted with caustic alkali, such as caustic soda or potash; (b) processes in which thecrude oil is washed with aqueous soda ash solution; and (c) processes in which the crude oil is first treated with a primary wash of aqueous soda ash solution followed by treatment with caustic alkali. The commercial processes may, of course, be slightly varied with a special 3 caustics ordinarily used, etc. In all of the above sterols, .break-' consituents and'the like and are separated from the oil by gravity settling or centrifugation. The resultant separated soap and entrained matter form the source materials for the preparation of antioxidants according to this invention. f the various types of soap stocks, those prepared by the simple contact of caustic soda in accordance with (a) above are the preferred source materials for the practice of this invention: however, soap stocks prepared by the other methods are entirely suitable.

At present. the soap stocks prepared as above outlined are usually marketed in the form of acids prepared by splitting the original soap stocks. For use in this invention, such acidulated soap stocks must be reconverted to the alkali soaps by treatment with alkali, either sodium or potassium. Accordingly, it is preferred to utilize 'the original soap stocks as separated from the refined oils, so as to avoid the unnecessary manipulations of acidulation and reconversion to soap.

The extractions according to this invention are conducted by contacting the soap stock with from about /2 to about-3 times its weight of any nonpolar solvent above indicated as suitable, at temperatures varying upwards of about 40 C. in cases wheresodium soap stocks are treated, and 30 C. in cases where potassium soap stocks are treated, to the boiling point of the solvent under the conditions of the extraction. In cases where ethylene dichloride is used, the boiling point will be between 80 and 90 C. In general, it will be preferred to operate between 60 and 70 C. The solvent and soap stock are thoroughly agitated together to insure contact of the solvent and soap stock. The solvent'and matter dissolved thereby will ordinarily spontaneously separate from the soap stock by gravity upon cessation of agitation, and may be removed mechanically. However, if necessary, or preferred, centrifugation may be employed. Ordinarily, a single extraction conducted in this manner will not remove all of the valuable antioxidant principles from the soap stock, which retains these principles with considerable tenacity. Accordingly, the usual procedure will be to repeatedly extract the residual soap stock with fresh lots of non-polar solvent. The several extract solutions may either be combined for further working up, or may be worked up separately. The solvent is removed from the combined extracts or several individual extracts, as the case may be, leaving an extract residue which constitutes the antioxidant product of this invention.

The residual soap stocks left behind by the extractions conducted according to this invention may be worked up in the usual ways in which ordinary soap stocks are treated, as by acidifioation, distillation, etc. For many of these purposes, the soap stocks will be greatly improved by having been subjected to the extraction of this invention.

The antioxidantv product produced as just outlined may be further refined, concentrated, etc. by any appropriate means such as fractionation with solvents, high vacuum distillation, etc.

While the composition of the antioxidant products of this invention is somewhat obscure, and moreover varies in accordance with the original vegetable oil and subsequent conditions 4 that the products contain, as active antioxidant components, various chromanes, quinones, quinols, tocopherols (as vitamin E) and similar compounds. In addition, the products also contain sterols. provitamin A, neutral oil and other undetermined substances.

The antioxidant extracts of this invention may be used to stabilize a wide variety of oxidationsusceptible pharmaceutical, alimentary and industrial products such as fat-soluble vitamin preparations on the order of vitamin A-, D- and E-containing oils, concentrates and the like; in foodstuffs, such as butter, margarine, fried products (such as potato chips), breakfast foods, salad oils, and the like; in cosmetic preparations, such as creams, lotions, etc.; and in industrial compositions such as lubricants, fuels and rubber compositions. The amount of antioxidant necessary to employ in any case will vary in accordance with the particular material to be stabilized, the source of the soap stock from which the antioxidant is produced, and the degree of antioxidant protection required. Accordingly, this amount is best determined by experiment in each case. 0.5% and about 7% of antioxidant based on the weight of material to be stabilized will provide a highly satisfactory degree of antioxidative stabilization.

The antioxidants of this invention exert a particulariy effective action when used in combination with phosphatides on the order of lecithin, soyabean lecithin and the like, which latter, although they themselves exert no substantial antioxidant action, nevertheless seem to greatly enhance the eflectiveness of the antioxidants of this invention. vBased upon the use of a single part, by weight, of the antioxidants of this invention, it will be found highly advantageous to employ in conjunction therewith from about fir to about 1 part of phosphatide. More of the phosphatide may be employed, but will not greatly enhance the effectiveness of the applicant's antioxidants.

there are given herewith concrete detailed examples of the practice of this invention. All parts given are by weight.

ts I Antioxidants from cottonseed soap stock Cottonseed oil soap stock parts 57 Ethylene dichloride six 1l4-part portions chloride layer was drawn oil and the soap layer extracted with the second portion of ethylene dichloride in the same manner. was repeatedly extracted in the same manner with the remaining portions of ethylene dichloride, making a total of 6 extracts. These extracts were combined and chilled to +3 C. and filtered. The clear filtrate was subjected to vacuum distillation to remove the ethylene dichloride, leaving a residue of 2.54 parts of a dark brown semisolid product. This product, hereinafter designated A," was found to stabilize awide variety of processing, it may be stated in a general way 75, of oxidation-sensitive materials against oxidative In general, between about With the foregoing general discussion in mind,

The soap stock properties.

deterioration. This material contained 25% unsaponifiable matter, as compared to less than 2%- for crude cottonseed oil. Quantitative data on accelerated tests or a vitamin A-containing oil stabilized with antioxidant A- are presented in the table hereinbelow after Example XV,

Product A and the first portion of the acetone were mixed and slightly warmed to eflfect a clear solution. This solution was then cooled to +3 C.

and kept at this temperature for five days. The 1 mixture was filtered, producing a crystalline residue B, which was washed with small portions of acetone at +3 C., and a filtrate C, the latter which included the washings Just mentioned. The residue B was dissolved with heating in the second portion of acetone, the solution cooled to +3 C., and held at this temperature for 18 hours. The resultant mixture was filtered producing a residue which was washed with small portions of acetone at +3 C., and a filtrate D" which included the washings last mentioned. Filtrates C and D" were combined, and the-acetone evaporated ofi until the solution comprised about 500 parts; This solution was kept at C. for 18 days. filtered, and the residue washed with small portions of cold acetone. The filtrate and washings were combined and the solvent evaporated ofi therefrom, leaving 101 parts of a product E having a high antioxidant potency. Results of tests conducted on this material are tabulated after Example XV. v

EXAMPLE III, Antioxidants from soyabean oil soap stock The procedure of Example I was preciselyrepeated using a soyabean oil soap stock in place of the cottonseed oil stock as a starting material. Corresponding to product A, there were obtained 1.74 parts of an orange-red solid product F having efiective antioxidant properties. This product contained 50% unsaponifiable matter as Compared'to less than 2% for crude soyabean oil. Quantitative data on accelerated tests of a vitamin A-containing oil stabilized with antioxidant F are represented hereinbelow after Example XV.

EXAMPLE IV Acetone fractionation of product "F I Parts Antioxidant F of Example III 163 Acetone: 1

1st portion 750 2d portion 400 The procedure of Example II was precisely repeated using the materials above listed in place of the corresponding materials of Example II. There were obtained 71 parts of a semi-solid product G, which exhibited effective antioxidant EXAMPLE V' Antioxidants from'cornoz'l soap stock The procedure of Example I was precisely repeated, using a corn oil soap stock in place of the cotton seed oil soap stock of Example I.

. to the product A 6 There were obtained 3.4 parts of a highly efficient antioxidant product H." corresponding of Example I, Product H was found to be a highly effective antioxidant in combination with a wide variety of oxidation labile materials. This product contained 41% of unsaponifiable material, as compared to less than 2% for crude corn oil. Quantitative data obtainedby tests of this material in admixture with a vitamin A-containing oil are presented hereinafter in the table following Example XV.

EXAMPLE VI Acetone fractionation of product "1! Parts Antioxidant Product 'H of Example V 70 Acetone:

1st portion 300 2d portion 400 The procedure of Example II was precisely repeated using the materials above listed in place of the corresponding materials employed in Example II. There were obtained 44 parts of a brilliantly clear liquid antioxidant product "J corresponding to the product E" of Example II. EXAMPLE VII Antioxidant from sopabean oil soap stock Parts Soyabean oil soap stock Trichloroethane:

1st portion 200 2d portion 200 3d portion 200 The soap stock and first portion of trichloroethane were mixed and agitated together at 70 C. The soap stock dissolved to a considerable extent at this temperature and, accordingly, the mass was cooled at 43 C. and permitted to separate into an upper soap stock layer and a lower trichloroethane extract solution layer, which latter was drawn all. The residual soap stock was successively extracted with the other portions of trichloroethane by the same procedure. The several extracts were combined, chilled to +3 C. and retained at this temperature for 18 hours. Thereafter, the solution was filtered, and the filtrate subjected to vacuum distillation to remove trichloroethane, yielding 18.3 parts of a dark orange-red antioxidant product K."

EXAMPLE VIII Antioxidant from soda ash corn oil soap stock Soda ash corn oil soap stock parts 200 Eethylene dichloride five 400-part portions The soap stock and the first portion of ethylene dichloride were mixed and agitated together at 60 C. to effect thorough contact therebetween, after which agitation was discontinued and a layer of ethylene dichloride (containing the material extracted thereby from the soap stock) was allowed to separate and was removed. The residual soap stock was again and again reextracted in the same manner successively with the Water amass Exmrne 1x Antioxidants from soda gen cottonseed oil soap stoc The procedure of Example vm was precisely repeated using a soda ash cottonseed oil soap stock in place of the corn oil soap stock of Example VIII. There were obtained parts-of a dark red clear viscous liquid antioxidant product M" having an iodine value of 100, a saponification value of 187, and containing 8% of unare recorded in the table following Example XV.

momma X Antioxidant from expeller souabean oil soap stock Expeller soyabean oil soap stock parts 500 Ethylene dichloride:

1st portion do 2000 together-in a kettle, an atmosphere of nitrogen being maintained over the surfaceof the kettle during this and all succeeding operations. The potassium hydroxide was then added and stirred in, the temperature rising to C. from the heat of saponiflcation. Stirring was discontinued. and the mass allowed to set for 18 hours. Thereafter,

, the mass-was heated to 60 C., the second portion saponifiable material. Test data on this product Additional portion seven 1000-part portions The soap stock and the first portion of ethylene dichloride were-mixed and agitatedtogether at 10 C. until thorough contact had beeneflected. Thereafter, the agitation was discontinued and the ethylene dichloride extract layer was permitted to settle and was removed. The residual soap stock was repeatedly'reextracted with the remaining portions of ethylene dichloride in the same manner. All of the extracts were combined, cooled to +3 C. and held at this temperature for 18 hours. Thereafter. the extracts were filtered, and the filtrate subjected to vacuum distillation to remove the ethylene dichloride, leaving behind 30 parts of a clear dark red viscous liquid antioxidant product N having an iodine value of 162 and containing 18% unsaponifiable material. Tests on this product are tabulated hereinbelow.

EXAMPLE XI The procedure of the preceding example was precisely repeated, using a soap stock produced a from hydraulic cottonseed oil and separated from the refined oil by centrifugation. There were obtained 22 parts of a clear dark red solid antioxidant product 0 (corresponding to prod uct N") having an iodine value of 106 and containing 31% unsaponifiable material. See the table hereinbelow for test data on this product.

EXAMPLE XII Antioxidant from empeller cottonseed oil soap stock The procedure of Example IX was precisely repeated using a soap stock obtained from an expeller cottonseed oil. There were obtained 12 parts of a solid black-red antioxidant product P. See the table for test data.

EXAMPLE EH 7 Y Antioxidant from acidulated soap stock Acidulated corn oil soap stock ..parts 60 Isopropanol do 1.8 Ethylene dichloride:

1st portion do.. 30

2d portion do 50 Additional portions three ISO-part portions Potassium hydroxide aqueous) Darts 28.8 do 7.4

The acldulated soap .stock, isopropanol and first portion of ethylene dichloride were blended of ethylene dichloride added, and the mass stirred well for 5 minutes. The water was then added and the'mass stirred for 16 minutes, maintaining the temperature throughout at 60 C. Thereafter, the stirring was discontinued, and the mass permitted to cool to 24 C. and allowed to stratify. The lower, ethylene dichloride extract, layer (hereinafter Q") was drawn oil. The residual soap stock was mixed with the third'portion oi ethylene dichloride, the mass heated to 60, vigorously agitated, cooled to 24 C.. permitted to stratify. and the lower, ethylene dichloride extract, layer (R") drawn ofi. This procedure was repeated with the remaining portions of ethylene dichloride, and the resultantextracts combined with the extracts Q" and "R." The combined extracts were filtered and subjected to vacuum distillation to remove the ethylene dichloride, leaving 2.61 parts of a brown, solid, highly effective, antioxidant product 8.

ExAmPLn XIV Acetone extract of product 5 Parts Products "8 (Example XIII) 778 Acetone 3112 Examrrn XV High vacuum distillation refinement v Product "1" parts 100 Methanol three 100-part portions The product T was mixed with the first portion of the methanol, heated to 60 C., chilled to 18 C., and filtered. The filtration residue was then reextracted successively with the other two portions of methanol. All the filtrates were combined and the methanol evaporated ofl? therefrom, leaving a dark maroon residue exhibiting strong antioxidant properties. This residue was then subjected to high vacuum distillation at 10*. The fraction coming over at about C. was a light yellow oil which was quite fiuid at '10 C. and exerted outstanding antioxidant power. The non-volatile fraction also exhibited some antioxidant properties.

STABIlJ'l'Y Tnsrs bility of a selected carbon-refined vitamin A-containing shark liver oil with and without the several antioxidants of this invention was checked by a series of tests each conducted as folthe antioxidants of this invention effectively.

restrain the destruction of vitamin A in compositions containing them. Likewise, it will be noted that in certain cases phosphatides were added and exerted a still further antioxidant efl'ect. although the phosphatides in themselves exert only negligible antioxidant powers.

Vitamin A potency of Added phosphaoil (Int. Units); Per Per tide cent Destruction of am 'Prodceit t Vitamin A afteruct' pro no used P Kind ii days ledays 20 days 45.0 76.0 None Note 1. 12 45. 0 A l. 0 28. 0 A 0 2. 7 16.5 A 1 1 9. 3 25. 2 A 3 1 5. 7 l4. 1 H E 1 l 7. 3 26.6 E 3 1 4. 0 19. 4 F 3 0 12. l 27. 4 III F 5 0 10. 6 24. 8 F 3 1 4. 7 14. 6 F 3 2 3. 7 12. 2 H 3 0 13. 0 35. 0 H 5 1 11.4 31.8 H 3 1 4. 65 18. 5 H 3 2 8. 7 17.2 M 3 0 17.6 68. 5 Ix M 5 0 e. 7 41. s "AI 3 1 9. 3 45. 5

M 5 1 9.05 30. 4 t 2 s 6 VIII L 3 1 l7. 1 61. 4 L 5 1 11. 0 44. 5 N 3 0 i0 24. 4 35.0 x N 5 0 6.65 16.7 27.8 N 3 l 1.4 9.4 10.8 13' g (1 1. 4 6. 3 8 v 6 1 0 5 1. P 3 0 2. 5 2. 1 3. 3 xrr g g P 5 1 NOTE 1: A purified soyahean lecithin sold under the trade name 7 Yelkin.

Nora 2: A commercial soyahean lecithin.

From the foregoing general discussion and specific examples, it will be apparent that this invention provides novel and highly efiective 10 finement of a vegetable oil, which comprises contacting said soap stock with ethylene dichloride at a temperature between about 40and about .90 0., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stock; separating the ethylene dichloride solution from the soap stock, and removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances.

2. Process for producing an antioxidant product from a soap stock obtained in the alkali refinement of a corn oil. which comprises contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 0., whereby the ethylene dichloride'forms a solution of antioxidant substances in the soap stock; separating the ethylene dichloride solution from the soap stock; and removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances.

3. Process for producing an antioxidant product from a soap stock obtained in the a kali refinementor a soybean oil. which comprises contacting said soap stock with ethylene dichloride at a temperature between about 40 C. and about 90 0., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stocky separating the ethylene dichloride solution from the soap stock; and removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances.

. 4. Process for producing an antioxidant product from a soap stock obtained in the alkali refinement of a cottonseed oil. which comprises contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 0., whereby the ethylene dichloride forms a solution of antiox dant substances in the soap stock: separating the ethylene dichloride solution from the soap stock; and removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances.

5. Process for producing an antioxidant product from a soap stock obtained in the alkali refinement c a vegetable oil, which comprises contacting said soap stock with ethy ene dichloride ethylene dichloride at a temperature between what is believed to be specifically novel, and is desired to be secured by Letters Patent, is:

1. Process for producing an antioxidant product from a soap stock obtained in the alkali reproduced by contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 .C., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stock; separating the ethylene moving the ethylene dichloride from the solution tion to leave a residue containing said antioxidant substances.

9. An antioxidant composition produced from a soap stock otbained in the alkali refinement of a cottonseed oil, said antioxidant composition being produced by contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 C. whereby the ethylene dichloride forms a solution 01' antioxidant substances in the soap stock; separating the ethylene dichloride solution from the soap stock: and re- 1 moving the ethylene dichloride from the solution to leave a residue containing said antioxidant substances. r

10. An antioxidant composition produced from a soap stock obtained in the alkali refinementof a vegetable oil, said antioxidant composition being'produced by contacting said soap stock with ethylene dichloride at a temperature between about 60 and about 70 (2., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stock; separating the ethylene dichloride solution from the soap stock; and removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances.

11. Process for producing an antioxidant product from a soap stock obtained in the alkali refinement of a vegetable oil, which comprises contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 6., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stock; separating the ethylene dichloride solution from the soap stock; removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances; and refining said residue to further concentrate the antioxidant substances. 1

12. Process for producing an antioxidant product from a soap stock obtained in the alkali reflnement of a vegetable oil. which comprises contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 C., whereby the ethylen dichloride forms a solution of antioxidant substances in the soap stock: separating thev ethylene dichloride solution from the soap stock; removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances: and subjecting the residue to high vacuum distillation to recover a fraction of increased antioxidant potency.

13. Process for producing an antioxidant prodtion from the soap stock; removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances; and recrystallizing said residue from an organic solvent to remove inactive materials to recover a traction of increased antioxidant potency.

14. Process for producing an antioxidant product from a soap stock obtained in the alkali refinement 01' a vegetable oil, which comprises contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 6., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stock:

separating the ethylene dichloride solution from the soap stock; removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances; recrystallizing said residue from an organic solvent to remove inactive materials; and subjecting the residue to high vacuum distillation to recover a fraction or increased antioxidant potency.

'15. An antioxidant composition produced from a soap stock obtained in the alkali refinement of a vegetabl oil, said antioxidant composition being produced by contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 C., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stock; separating the ethylene dichloride solution from th soap stock; removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances; and refining said residue to iurther concentrate the antioxidant substances.

16. An antioxidant composition produced from a soap stock obtained in the alkali refinement of a vegetable oil, said antioxidant composition being produced by contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 0., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stock; separating the ethylene dichloride solution from the soap stock; removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances; and subjecting the residue to high vacuum distillation to recover a fraction of increased antioxidant potency.

17. An antioxidant composition produced from a soap stock obtained in the alkali refinement of a vegetable oil, said antioxidant composition being produced by contacting said soap stock with ethylene dichloride at a temperature between about 40 and about 90 (2., whereby the ethylene dichloride forms a solution of antioxidant substances in the soap stock; separating the ethylene dichloride solution from the soap stock; removing the ethylene dichloride from the solution to leave a residue containing said antioxidant substances; and recrystallizing said residue from an organic solvent to remove inactive materials dichloride forms a solution of antioxidant substances in the soap stock; separating the ethylene dichloride solution from the soap stock; removing the ethylene dichloride from the solution to leave a residue containing said antioxidant sub,-r=

stances; recrystallizing said residue from an or ganic solvent to remove inactive materials; and

subjecting the residue to high vacuum distillatlon to recover a. fraction of increased antioxidant potency.

' LORAN 0. BUXTON.

REFERENCES CITED The following references are of record in the file of this patent:

10 UNITED STATES PA'I'EN'I'S Number Name Date 2,113,216 Mitchell Apr. 5, 1938 2,280,815 Fernholz Apr. 28, 1942 2,296,794

Kruse et a1... Sept. 22, 1942 15 14 Number Name Date 1,947,432 Huston Feb. 13, 1934 2,098,254 Mattlll et al Nov. 9, 1937 2,182,767 Thurman Dec. 5, 1939 1,575,529 Bellman Mar. 2, 1926 OTHER REFERENCES