US3701767A - Peroxide bleaching of epoxidized fatty acid esters - Google Patents

Abstract

A PROCESS OF BLEACHING EPOXIDIZED FATTY ACID ESTERS BY TREATING THE ESTERS CONCURRENTLY WITH AN ALKALINE MATERIAL AND WITH HYDROGEN PEROXIDE. EXAMPLES OF SOME SUITABLE EPOXIDIZED FATTY ACID ESTERS ARE EPOXIDIZED SOYBEAN OIL AND EPOXIDIZED OCTYL TALLATE. SODIUM HYDROXIDE IS THE PREFERRED ALKALINE MATERIAL.

Description

United States Patent Ofice 3,701,767 Patented Oct. 31, 1972 3,701,767 PEROXIDE BLEACHING F EPOXIDIZED FATTY ACID ESTERS William H. French, St. Paul, Minn., and Brian M. Rushton, Williamsville, N.Y., assignors to Ashland Oil, Inc., Houston, Tex. No Drawing. Filed Feb. 2, 1971, Ser. No. 112,086 Int. Cl. C09f 1/02 US. Cl. 260-975 14 Claims ABSTRACT OF THE DISCLOSURE A process of bleaching epoxidized fatty acid esters by treating the esters concurrently with an alkaline material and with hydrogen peroxide. Examples of some suitable epoxidized fatty acid esters are epoxidized soybean oil and epoxidized octyl tallate. Sodium hydroxide is the preferred alkaline material.

BACKGROUND OF THE 'INVENTION This invention relates to a process for bleaching epoxidized fatty acid esters. More particularly, it relates to a process for bleaching epoxidized fatty acid esters employing the concurrent action of an alkaline material and hydrogen peroxide.

Various epoxidized fatty acid esters have been widely used as plasticizers, stabilizers, and surface active agents. For instance, various epoxidized fatty acid esters enjoy commercial acceptance as suitable plasticizers for numerous synthetic polymers, and particularly for vinyl chloride containing polymers, such as polyvinyl chloride.

Generally, the epoxidized fatty acid esters are discolored somewhat as initially obtained from the usual commercial methods of preparation. It is quite important, however, that these materials have as light a color as possible. This is particularly true when they are to be used as plasticizers, stabilizers, and surface active agents. Accordingly, various attempts have been made in the art to decolorize these epoxidized fatty acid esters in order to substantially reduce or eliminate the color.

Included among such prior decolorization processes are treatment with caustic; and adsorption of color by activated carbon, alumina, silica gel, or treated clays. Most of these prior decolorization techniques, however, do not effectively reduce the color of the material to provide products of acceptable light color such as a color of less than 100 APHA. In addition, some treated clays are highly acidic and therefore may cause decomposition of the epoxides resulting in loss of the product.

The process of the present invention provides a bleaching process which is quite efiicient. The process of the present invention provides products which have been decolorized to a surprisingly low level in a relatively fast time.

BRIEF DESCRIPTION OF THE INVENTION The process of the present invention is concerned with bleaching epoxidized fatty acid ester by treating the ester concurrently with from about 0.1 to about 2% by weight based upon the ester of alkaline material and with from about 0.25 to about 2% by weight based upon the ester of hydrogen peroxide, and in the presence of up to about 40% by weight of water based upon the ester. The ester is treated at a temperature from about ambient to about 200 F. for a time suflicient to reduce the color of the epoxidized fatty acid ester.

DESCRIPTION OF PREFERRED EMBODIMENT The epoxidized fatty acid esters suitable in the present process are the epoxidized mono-, di-, tri-, tetra-, penta-, and hexa-hydric alcohol esters of fatty acids.

Some suitable monohydric saturated aliphatic alcohols providing the alcohol moiety of the ester include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, isoamyl, hexyl, heptyl, octyl, nonyl, and decyl alcohols.

Suitable dihydric alcohols include among others the lower glycols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, diethylmethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, 1,3- butanediol, 1,4-butanediol, and 2,3-butanediol.

Suitable aliphatic alcohols which contain from 3 to 6 alcohol groups include glycerol, erythritol, pentaerythritol, dipentaerythritol, and hexitols, such as mannitol and sorbitol.

In addition benzenoid alcohols having less than 10 carbon atoms may be employed as the alcohol moiety in the epoxidized fatty acid esters of the present invention. Such alcohols include benzyl, phenyl, Z-phenylethyl, l-phenylethyl, and nuclear methylated phenyl alcohols. Other cycloaliphatic alcohols such as cyclohexanol can be employed as the alcohol moiety in the esters used herein.

Of particular importance are the epoxidized triglycerides such as the epoxidized animal, epoxidized vegetable, and epoxidized marine oils.

Examples of some suitable epoxidized fatty acid esters are the epoxidized derivatives of the following materials: tallow, soybean oil, linseed oil, talloil esters, safflower oil, sunflower oil, perilla oil, sperm oil, menhaden oil, and cottonseed oil. The epoxidized fatty acid esters generally have an oxirane content of about 3.5 to 9.5%, and an iodine value less than 4. Preferably the epoxidized fatty acid esters are esters of fatty acids having from 10 to 22 carbon atoms.

The epoxidized compounds which are bleached according to the present invention are commercially available and are readily obtainable by known methods fully described in numerous US. and foreign patents. For example, see -U.S. Pats. 2,458,484 and 2,569,502. Of particular importance are the epoxidized compounds obtained by the reaction of the corresponding ethyle'nically unsaturated acid or ester with a strong oxidizing agent such as peracetic acid or hydrogen peroxide in an acid medium for upwards to 15 hours. In such a process the unsaturated compound is substituted at the site of unsaturation with an oxirane oxygen.

These epoxidized materials as obtained from such a process still retain color and should be bleached if they are to be employed as plasticizers, stabilizers, and/or surfactants. For example, an epoxidized ester such as epoxidized soybean oil may contain the following impurities which may contribute to the color of the epoxidized fatty acid ester:

(1) phospholipides such as lecithin, cephalin and sphingomyelin;

(2) sterols such as cholesterol, stigmasterol and ergosterol;

(3) tocopherols;

(4) lipochromes such as l-gossypol;

(5) carotenoids (polyene pigments) such as lycopene, gamma carotene, beta carotene, alpha carotene and xanthophylls; and

(6) chlorophyll.

Although these above materials may be present in the epoxidized oil in merely trace amounts or even present in undetectable quantities, their discolorization effect can be quite noticeable. Accordingly, even a slight decrease in the quantity of the impurities over the prior art can have a tremendous effect upon the usefulness of the epoxidized compounds in large scale commercial applications. It is quite apparent that the bleaching of the materials of the present invention is quite difficult in that the discoloring impurities are present in such small amounts that to get rid of them becomes quite difiicult.

The alkaline material suitable for the present invention includes sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, barium hydroxide, ammonium hydroxide and lithium hydroxide. For best results the alkaline material should be water soluble. Thepreferred alkaline materials are the sodium materials because of their color stability properties. For instance, if small amounts of such alkaline materials as potassium hydroxide, barium hydroxide and ammonium hydroxide remain in the product after bleaching, they may tend to discolor the product a little if exposed to high temperatures for any great length of time. On the other hand, the sodium materials are not likely to cause such discoloration.

The minimum quantity of alkaline materials which can be present in the process of this invention is about 0.1%. Amounts less than this quantity will not be sufficient to provide a noticeable reduction in the color of the material. The maximum quantity of alkaline material that may be employedin the present process is about 2% by weight based upon the epoxidized fatty acid ester. Quantities greater than 2% by weight based upon the epoxidized material are not desirable since large losses of the desired product may occur. Such losses may be due to emulsification of some of the epoxidized fatty acid ester and also due to saponification of the fatty acid ester. Of course some loss of product can be tolerated with the maximum amount being determined by practical and economical considerations. The preferred quantities of alkaline material to be employed are between about 0.3% and about 0.8% by weight based upon the weight of the epoxidized fatty acid ester. Preferably the alkaline material is added as a dilute aqueous solution. Suitable concentrations of aqueous solution contain from about 2.5% to about by weight of the alkaline material.

Also the alkaline material must be added in an amount sufiicient to provide the reaction mass which is being bleached with a pH that is basic (pH greater than 7). Preferably the pH of the reaction mass should be at least about 9.

The hydrogen peroxide is most conveniently added as an aqueous peroxide solution containing from about to about 90% by weight of hydrogen peroxide. Preferably the aqueous hydrogen peroxide solution should contain between about 50% and about 70% by weight of hydrogen peroxide.

The minimum quantity of hydrogen peroxide which can be present in the process is about 0.25% by weight based upon the epoxidized fatty acid ester. Amounts less than this quantity will not be sufficient to provide a noticeable reduction in the color of epoxidized fatty acid ester. The maximum quantity of hydrogen peroxide that may be employed in the present process is about 2% by weight based upon the epoxidized compound.

Amounts greater than the 2% by weight based upon the weight of the epoxidized fatty acid ester may cause an increase in the acid value of the ester and consequently reduce the value of the fatty acid ester as a plasticizer. Accordingly, it is quite important that the peroxy compound be employed in the amounts specified in order to achieve the: desired decolorizing effect while maintaining the usefulness of the epoxidized compounds as a plasticizer.

Of course, it is understood that the alkaline material and hydrogen peroxide need not be added as two separate compounds but can .be added as a single compound. For example, sodium peroxide can be used instead of sodium hydroxide and hydrogen peroxide.

The total quantity of water which may be present during the treatment with the alkaline material and the hydrogen peroxide can be as much as about 40% based upon the weightof the epoxidized fatty acid ester. If

quantities above 40% by weight based upon the epoxidized fatty acid ester are present then the treatment will be ineffective since the dilution effect will be too great for an effective bleach. The preferred quantities of water to be present during the bleaching process are from about 4% to about 25% by weight based uponthe weight of theepoxidized fatty acid ester.

The presence of at least some water in the process (e.g., at least 2% by weight based upon the weight of the epoxidized material) is desirable, since some of the discoloring impurities are water soluble. in the presence of hydrogen peroxide and the alkaline material. Accordingly, the water would facilitate separation of the discoloringmaterials from the desired product.

It is extremely crucial to the success of the present process that the epoxidized fatty acid ester be treated with the alkaline material and the hydrogen peroxide concurrently. That is, the alkaline material and hydrogen peroxide are to be present so that they coact upon the epoxidized fatty acid ester;

For instance, it has been suggested to treat certain epoxidized oils to improve the heat stability and odor of the oil by first oxidizing with an aqueous hydrogen peroxide solution, followed by water washing, and then neutralization with sodium hydroxide. Such a treatment as will be demonstrated in the examples does not bleach the oil to any greater extent than if the oil were merely treated with the sodium hydroxide alone. Such as process is not disclosed as being a more effective bleach than a caustic treatment. In fact, in some instances such a treatment even increases the color. In addition, applicants have reversed that process by first treating with sodium hydroxide, water washing and then oxidizing with hydrogen peroxide. Even this sequence of steps does not provide a bleaching process which is more effective than the caustic treatment per se.

Accordingly, the success of the present invention is quite dependent upon the concurrent treatment of the epoxidized fatty acid ester with the alkaline material and the hydrogen peroxide.

Also as will be demonstrated herein below, the treatment of the epoxidized fatty acid esters of the present invention with only hydrogen peroxide will not appreciably change the colorv of the epoxidized fatty acid ester. It has been suggested to treat certain epoxy compounds with aqueous hydrogen peroxide solutions to prevent color development but not to bleach the material. The prevention of color development is not the same as bleaching and is recognized in the art as an entirely different problem.

The process of the present invention can be carried out at temperatures ranging from about ambient to about 200 F. Temperatures above 200 F. may cause some darkening of the material and should therefore be avoided. Of course, some of the epoxidized fatty acid esters could be heated to above 200 F. without any adverse affect. However, for practical purposes the process should be carried out at temperatures no higher than 200 F. Temperatures below ambient should not normally be employed sincethe treatment would probably require too much time to be satisfactorily employed in a commercial operation. In addition these lower temperatures may make the separation of the epoxidized fatty acid ester from the aqueous phase difficult. Preferably the temperature should be in the range of from about F. to about F.

Atmospheric pressure is most conveniently employed in carrying out the process of the present invention. However, higher or lower pressures can be employed when desired.

The bleaching process of this invention has generally been carried out in about /2 hoiur to about 6 hours. Generally the time of bleaching will vary between about 1 hour and about 2 hours. Of course, the time will be somewhat dependent upon the materials being bleached, the amount of alkaline material, the amount of hydrogen peroxide, the temperature, and the degree of bleaching desired.

The treatment of the epoxidized fatty acid ester with the alkali material and the hydrogen peroxide can be achieved by any of the conventional means of intimately contacting two or more materials with each other. For instance, the process of the present invention can be readily carried out by merely mixing the materials together. Of course the time necessary to achieve a desired level of bleaching can be decreased if instead of mere mixing, the materials are rapidly agitated. However, when using high agitation and high shear, care must be taken so that the epoxidized fatty acid ester and water present do not form an emulsion. The formation of an emulsion would consequently cause great problems in the separation of the expoxidized fatty acid ester from the other materials. If an emulsion forms, it may be necessary to employ a centrifuge to break the emulsion.

It was quite unexpected that the process of the present invention would bleach the epoxidized fatty acid esters. Since the epoxidized material has probably already been exposed for several hours (up to about 15 hours) to the action of strong oxidizing agents such as the hydrogen peroxide and peracetic acid, it would be expected that the epoxidized fatty acid ester has been bleached as far as possible by oxidation. However, according to the present invention, when the epoxidized material is treated concurrently with the hydrogen peroxide and the alkaline material an excellent bleaching process is provided.

Although it has been suggested that to bleach paper one employ various combinations of sodium hydroxide and hydrogen peroxide, it would not be expected that the vastly different material of the present invention would be bleached by such a means. The impurities present in paper and those which may be present in the epoxidized materials are vastly different and are not considered equivalent. It is well known that the success of a bleaching operation is quite dependent upon the particular material which is being bleached. It cannot be predicted that a bleaching process suitable for one type of material will be useful for a vastly different type of material.

In order that the invention may be better understood the following examples are given in which the amounts are by weight unless the contrary is stated.

Example 1 To 180 parts of an epoxidized soybean oil having an oxirane content of 6.95%, an acid value of 0.60, an iodine value of 1.99, and a color of 120 APHA is added a mixture of 36 parts of a 4% aqueous NaOH solution, and 4.5 parts of a 50% aqueous H solution. The mixture of the soybean oil, NaOH, H 0 and water is then agitated at 150 F. for 1 hour. 78 parts of heptane are added to the mixture and the epoxidized soybean oil is separated. Separation can be accomplished by use of a centrifuge without adding a solvent. Then 36 parts of water and 0.3 part of acetic acid are added to the epoxidized soybean oil. This mixture is agitated at 150 F. for .5 minutes after which the epoxidized soybean oil is separated. The epoxidized soybean oil is then vacuum stripped to evaporate the residual heptane and water is finally filtered. The epoxidized soybean oil is bleached to a color of 55 APHA.

Example 2 To 300 parts of the same epoxidized soybean oil as in Example 1 is added a mixture of 30 parts of water and 30 parts of a 50% aqueous H 0 solution. The mixture of the soybean oil, H 0 and water is then agitated at 150 F. for 1 hour. The mixture is then Washed with 200 parts of water. This washing is repeated 2 more times. The epoxidized soybean oil is separated and dried whereby it is bleached to a color of 110 APHA.

To this epoxidized soybean oil is added 90 parts of a 30% aqueous NaOH solution. This mixture of epoxidized soybean oil, NaOH and water is agitated at 150 F. for 1 hour. The mixture is washed with 200 parts of water. This washing is repeated 4 times The epoxidized soybean oil is dried under vacuum whereby it is bleached to a color of APHA.

Example 3 To 300 parts of the same epoxidized soybean oil as in Example 1 are added parts of a 3% aqueous NaOH solution. The mixture of the soybean oil, NaOH, and water is then agitated at 150 F. for 1 hour. The mixture is then washed with 300 parts of water. This washing is repeated 3 more times. The soybean oil is separated, dried and filtered whereby it is bleached to a color of 80 APHA and an acid value of 0.05.

To this epoxidized soybean oil is added a mixture of 30 parts of a 50% aqueous H 0 solution and 30 parts water. This mixture of epoxidized soybean oil, H 0 and water is agitated at 150 F. for 1 hour. The mixture is washed several times at 150 F. with water, vacuum stripped and dried after which is obtained an epoxidized soybean oil having a color of 75 APHA.

Example 4 To 300 parts of the same epoxidized soybean oil as Example 1 are added 60 parts of a 4% aqueous NaOH solution. The mixture of the soybean oil, NaOH, and water is then agitated at 150 F. for 1 hour. parts of heptane are added to the mixture and the oil is separated. Then 60 parts of water and .5 parts of acetic acid are added to the epoxidized soybean oil. This mixture is agitated at 150 F. for 1 hour after which the epoxidized soybean oil is separated. The epoxidized soybean oil is then vacuum stripped. The soybean oil is bleached to a color of 80 APHA.

Example 5 To 100 parts of an epoxidized soybean oil having an oxirane content of 6.70%, an acid value of 0.2, an iodine value of 2.0, and a color of APHA are slowly added together a solution of 19.2 parts of distilled water and 0.80 part NaOH, and a solution of 0.71 part distilled water and 1.79 parts of a 70% aqueous H 0 solution. The mixture of the soybean oil, NaOH, H 0 and water is then agitated at F. for 1 hour. 50 parts of heptane is added and the water layer separates. Then 100 parts of hot water are added and the mixture is heated to 140 F. The water layer separates breaking an emulsion that is present. 20 parts of water and 0.16 parts of acetic acid are added to the oil layer. This mixture is agitated at 140 F. for 10 minutes. The water layer is then separated. The oil layer is vacuum stripped at 200 F. for 10 minutes. The epoxidized soybean oil is bleached to a color of 75 APHA.

Example 6 To 100 parts of the same epoxidized soybean oil as in Example 5 is added a mixture of 5.30 parts of distilled water and 5.32 parts of a 70% aqueous H 0 solution. The mixture of the soybean oil, H 0 and water is then agitated at 140 F. for 2% hours. 100 parts of water are added and the materials are mixed for 1% hours. 0.4 part of a 50% NaOH solution are added and the mixture is agitated at 140 F. for 10 minutes. 50 parts of heptane are added and the oil phase which is separated is washed with 100 parts of water. The oil phase is separated and is vacuum stripped at 200 F. for 10 minutes and finally filtered. The epoxidized soybean oil has a final color of 130 A-PHA.

Example 7 To 100 parts of an epoxidized soybean oil having an oxirane content of 6.97%, an acid value of 0.50, an iodine value of 1.85, and a color of 120 APlHA are added 4 parts of a 10% aqueous NaOH solution, and 2.5 parts of a 50% aqueous H 0 solution. The mixture of the soybean oil, NaOH, H 0 and water is then agitated at F. for 1 hour. 43 parts of heptane are added and the oil layer is separated. The oil phase is washed with 4 parts of water and v0.1 part of acetic acid at 160 F. for '5 minutes. The oil phase is then dried under vacuum at 200 F. and is filtered. 98 parts of an epoxidized soybean oil having a color of 35 A-PHA and an acid value of 0.25 are recovered. About 2 parts of the epoxidized soybean oil is lost in the aqueous layer due to the quantity of NaOH being slightly high causing saponification of the oil.

Example 8 To 100 parts of the same epoxidized soybean. oil as in Example 7 are added 4 parts of a 10% aqueous NaOH solution, and 1.25 parts of a 50% aqueous H solution. The mixtureof the soybean oil, NaOH, H 0 and water is then agitated at 160 F. for 1 hour. 43 parts of heptane are added and an oil layer is separated. The oil phase is washed with 4 parts of water and 0.1 part of acetic acid at 160 F. for 5 minutes. The oil phase is then dried under vacuum at 200 F. and then filtered. 96 parts of an epoxidized soybean oil having a color of 35 APHA and an acid value of 0.35 are recovered. About 4 parts of the epoxidized soybean oil are lost in the aqueous layer due to the quantity of NaOH being slightly high causing .saponification of some of the oil.

Example 9 To 100 parts of the same epoxidized soybean oil as used in Example 7 is added a mixture of 4 parts of a 2.5% aqueous NaOH solution, and 1.25 parts of a 50% aqueous H 0 solution. The mixture of the soybean oil, NaOH, H 0 and water is then agitated at 160 for 1 hour. 43 parts of heptane are added and the oil phase is separated by decanting. The oil phase is washed with 4 parts of water and 0.1 part of acetic acid at 160 F. for 5 minutes. The oil phase is then dried under vacuum at 200 F. and then filtered. An epoxidized soybean oil havinga color of 65 AP I-IA and an acid value of 0.60 is recovered.

Example 10 To 85 parts of an epoxidized soybean oil having an oxirane content of 6.97%, an acid value of 0.5, an iodine value of 1.85, and a color of 120 APHA is added a mixture of 3.4 parts of a 5% aqueous NaOH solution and 1.063 parts of a 50% aqueous H 0 The mixture of the soybean oil, NaOH, H 0 and water is then agitated at 160 F. for 1 hour. vThe epoxidized soybean oil is separated. from the mixture by centrifuging. Then 4 parts of water and 0.1 parts of acetic acid are added to the epoxidized soybean oil. This mixture is agitated at 160' F. for 5 minutes after which, the epoxidized soybean oil is separated. The epoxidized soybean oil is then stripped to evaporate the residual heptane and water and is finally filtered. The epoxidized. soybean oil is bleached to a color of 55 APHA and the yield is about 98.1%.

Example 1 1 To 100 parts of an epoxidized linseed oil having an oxirane content of 8.98%, an acid value of 0.9', an iodine value of 4.6, and a color of 95 APHA is added a mixture of 4 parts of a 10% NaOH solution and 1.25 parts of a 50% aqueous H 0 solution. The mixture of the linseed oil, NaOH, H 0 and water is then agitated at 160 F. for 1 hour. 43 parts of heptane and 4 parts of water are added to the mixture and the epoxidized linseed oil is separated. Then 4 parts of water containing 0.1 part acetic acid are added to the epoxidized linseed oil. This mixture is agitated at 160 F. for 10 minutes, after which the epoxidized linseed oil is separated. The epoxidized linseed oil is then vacuum stripped to evaporate the residual heptane and water and is finallyfiltered. The epoxidized linseed oil is bleached to a color of about 25 and the yield is 97.5%.

Example 12 To 100 parts of the epoxidized octyl tallate having an oxirane content of 4.73%, a hydroxyl value of 25.3,

8 an iodine value of 3.3, and a color of APHA are added 20 parts of a 4% aqueous NaOH solution and 2.5 parts of a 50% aqueous H 0 solution. The mixture of the epoxidized octyl tallate, NaOH, H 0 and water is then agitated at 150 F. for 2 hours. 43 parts of heptane are added to the mixture and the oil is separated. Then 20 parts of water and 0 .16 part of acetic acid are added to the epoxidized octyl tallate. This mixture is agitated at 150 F. for 1 hour after which the epoxidized octyi tallate is separated. The epoxidized octyl tallate is then steam stripped under vacuum and is filtered. The epoxidized octyl tallate is bleached to a color of 40 APHA and the yield is 9 8.1%.

Example 13 To 5 0 parts of epoxidized octyl tallate having an oxirane content of 4.42%, an acid value of 0.8, an iodine value of 5, and a color of 5 Gardner are added 2 parts of a 10% aqueous NaOH solution and 0.625 parts of a 50% aqueous H 0 solution. The mixture of the epoxidized octyl tallate, NaOH, H 0 and water is then agitated at 140 F. for 3 hours. The epoxidized octyl tallate is separated from the mixture by centrifuging and is filtered. The epoxidized octyl tallate .is bleached to a color of between 1 and2 Gardner.

The epoxidized materials bleached in the examples are obtained by epoxidizing the corresponding unsaturated material with hydrogen peroxide or peracetic acid for at least 10 hours in an acid medium according to known technology. For instance, the epoxidized octyl tallate employed in Example 12 is prepared as follows:

To 400 parts of octyl tallate having an iodine number of 98 are added 126 parts of a 50% H 0 aqueous solution and 39 parts of a 83% acetic acid solution. A mixture of 16.8 parts of a 83% acetic acid solution and 2.5 partsof sulfuric acid is then added with stirring. This reaction mixture is maintained at about 137 F. for 14.5 hours. The mixture is then cooled and 0.1 part of lime are added. The mixture is steam stripped and filtered whereby epoxidized octyl tallate having an oxirane content of 4.73%, an iodine value of 3.3, a hydroxyl value of 25.3 and a color of 90 APHA- is obtained. This is the epoxidized material which is bleached in" Example 12.

A comparison of Examples 2-4, which are outside the scope of the present invention, with Example 1 clearly illustrates the improved bleaching obtained by the present process and the necessity of concurrently treating with the alkaline material and peroxy compound. Example 6 clearly shows that treatments with both the peroxy compound and alkaline material according to a method previously suggested actually increases the color.

The results of Examples 1-13 are set forth below in the table.

Original- Concurrent color color Example No. Additive treatment APHA APHA 1 0.8% NaOH, 1.25% Yes 55 2 Z- 2 5% H202, 0.9% No 15(5) a 3 0.9% NaOH, 5% N o 120 80 E202. 80 75 4 0.8% NaOH N0 120 80 5 0.8% NaOH, 1.25% Yes 120 75 H202. 6 3.7N% 1112102, 0.2% No I20 a 7 Aibl IgaOH, 1.25% Yes 120 35 2 2- 8 4% NaOH, Yes 120 35 H202. 9 0.1% NaOH, Yes 120 65 0.625% H202. 10 0.2% NaOH, Yes 120 55 0.625% H101. 11 .do Yes 05 25 12 0.%%( IaOH, 1.25% Yes 9O 40 2 2- 13 0.4% NaOH, Yes I 5 1-2 1 Color is Gardner.

The APHA color is determined by a slightly modified method color comparison means with platinum-cobalt tit ' Designation co\or determination a standard stoc s and cobalt which will be reterred to hereinbelow as No. 500 Stock Solution is prepared as iollows'.

(a) 1.245 grams of potassium chloroplatinate (K PtCl analytical reagent and 1.000 gram of cobalt chloride (CoCl -6H O), American Chemical Society Grade (ACS grade) are dissolved in distilled water in a 250 ml. volumetric ask;

(b) 25 ml. of HCl (sp. gr. 1.18) ACS grade are then added;

() the solution is diluted to 250 ml. with distilled water;

(d) the 250 ml. solution from step (c) is then transferred to a 1000 ml. volumetric flask;

(e) 75 ml. of HCl (sp. gr. 1.18) ACS grade are then added; and

(f) the solution is then diluted to 1000 ml. with distilled water which has first been passed through the 250 ml. volumetric flask in order to wash out any residual chemicals therein.

This 1000 ml. solution has a color of 500 APHA. The 250 ml. solution from step (c) has a color of 2000 APHA. The color standards are then prepared from the No. 500 stock solution by diluting the required No. 500 stock solution as set forth in the table below to 50 ml. with distilled water in 50 ml. tall form Nessler test tubes. Size No. 1 Kimble N0. 45315A or B No. 500 Stock Color standard solution, ml.: number, APHA .5 1 1.5 2 2.5 3 3.5 4 5 50 6 6O 7 7O 10 100 15 150' 20 200 25 250 30 300 35 350 40 400 450 500 the 50 ml. mark and then comparing it with the nearest 1 tanking vertically downward L n an... oi piaiitiiiiii ama, a m Wlz/ 13" aim/m {WE/1101.917 0/ Wild figs bon atoms and having Qii f less to 9.5 and an iodine value 0- treating sa'd epoxidized fatty acid ester concurrently with from about 0.1 to about 2% by weight based upon said ester of a water soluble alkaline material and wit from about 0.25 to about 2% by weight based upon said ester of hydrogen peroxide in the presence of from at least 2% to about 40% by weight of water based upon said ester, for a time suflicient to reduce the color of said epoxidized fatty ac'd ester, with the proviso that said amount of alkaline material is also sufficient to provide a pH of greater than 7.

2. The process oi claim 1 wherein said epoxidized fatty acid ester is ep'oxidized soybean oil.

of claim 1 wherein said epoxidized fatty acid ester is epoxidized octyl tallate.

4. The process of claim 1 wherein said epoxidized fatty acid ester is epoxidized linseed oil.

5. The process of claim 1 wherein said alkaline material is sodium hydroxide.

6. The process of claim 3 wherein said sodium hydroxide is added as an aqueous sodium. hydroxide solu- 7. The process of claim 4 wherein said aqueous solu- 30 tion contains from about 2.5% to about 15% by weight of sodium hydroxide.

8. The process of claim 1 wherein said hydrogen peroxide is added as an aqueous hydrogen peroxide solution.

35 9. The process of claim 8 wherein said aqueous solution contains at least 50% oxide.

10. The process of claim 7 wherein said aqueous solution contains between about 50% and by weight by weight of hydrogen per- 9 of hydrogen peroxide.

11. The process of claim 1 which is carried out in the presence of from about 4% to 25% by weight of water based upon the weight of the epoxidized fatty acid ester. 5 12. The process of claim 1 wherein said temperature is from about to F.

wherein said epoxidized fatty acid ester 18 treated for about V2 to 6 hours.

14. The process of claim 1 wherein said epoxidized 5 fatty acid ester 15 treated for about 2 hours.

References Cited UNITED STATES PATENTS 2,935,517 5/1960 Gall et al. 260-348 2,569,502 10/1951 Swern et al. 260--348 FOREIGN PATENTS 702,779 1/1965 Canada 260-97.5

60 DONALD E. CZAJA, Primary Examiner W. E. PARKER, Assistant Examiner US. Cl. X.R.

col 1 10 umn of liquid. Of course, at night regular daylight illlllll iii than 4 which compllse Patent No. 7 Dated October 31, 1972 William H. French and Brian Rushton Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 4, line 37; "per se" should be corrected to er s3- In Column 5, line 73; "30%" should be corrected to 3%-.

Signed and sealed this 17th day of September 1974,

I; EAL Arrest:

MCCOY Mo GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents -1 5 10-69 FORM PO 0 o( USCOMM-DC 60376-P69 u 5 GOVERNMENT PRINTING OFFICE: I969 o-3ss-334