US3150153A - Stability of epoxidized oils by oxidation and naturalization - Google Patents

Description

United States Patent O M 3,150,153 STAiilLlTY OF EPOXIDIZED OILS BY OXl'DATION AND NATURALEZATION Stuart A. Harrison, Minneapolis, and Harry G. Simmerrnan, St. Paul, Minn asslgnors to General Mills, Inc., a corporation of Delaware No Drawing. Filed June 15, 1962, Ser. No. 202,632 7 Claims. (Cl. Zed-348) The present invention relates to a process of treating epoxidized oils. More particularly, it relates to such a process wherein the heat stability and/or odor of epoxidized oils is improved by oxidizing and then neutralizing said oils.

Epoxidized oils are particularly valuable as plasticizers for resins such as polyvinyl chloride, polyvinyl acetate, copolyrners of vinyl chloride and vinyl acetate, polyvinyliclene chloride, polyvinyl butyral, nitrocellulose chlorinated rubber and the like. A wide variety of articles (draperies, luggage, handbags, etc.) have been made from such plasticized materials. It is highly desirable, if not essential, that such plasticized materials and the articles prepared therefrom be relatively heat stable and without offensive odors. However, many of the known epoxidized oils lack the desired heat stability and/ or have otfensive odors which undesirable properties are passed on to the resinous materials plasticized with said oils.

We have now discovered that the heat stability and odor of epoxidized oils can be improved by oxidizing and then neutralizing said oils. In this way, the value of the oils as plasticizers is greatly increased.

It is, therefore, an object of the present invention to provide a novel process for treating epoxidized oils.

Another object of our invention is to provide a process for improving the heat stability and/ or odor of epoxidized oils.

These and other objects will become apparent from the following detailed description.

The epoxidized oils which may be treated according to the process of the present invention include the aliphatic and cycloaliphatic, aryl and aralkyl esters of epoxy fatty acids, the fatty acid group containing from about 8 to 22 carbon atoms. The fatty acid group may be derived from any animal, vegetable or marine oil containing un saturated fatty acid groups; they may be derived from the mixed fatty acids contained in such oils; or they may be derived from isolated unsaturated fatty acids, either naturally occurring or synthetic. A wide variety of alcohols may be used for esterification of the described epoxy fatty acids. These alcohols include those having a hydrocarbon group attached to the hydroxyl group and include par* ticularly monohydric aliphatic alcohols such as methanol, ethanol, propanol, butanol and the like; polyhydric alcohols such as the glycols, diethylene glycol and the like; and glycerols and polyglycerols, etc. The alcohols used for esterification also include the aromatic alcohols such as phenol; the aralltyl alcohols such as benzyl alcohol; and cycloaliphatic alcohols such as cyclohexanol.

While any of the described oils may be treated by our process, it is particularly applicable to those prepared from naturally occurring oils, such as soybean oil, which have been epoxidized using non-aqueous peracetic acid as described in the Phillips and Starcher Patent No. 2,785,- 185. Such oils have high odor and poor heat stability be lieved to be caused by high acid values. However, mere neutralization of said oils with caustic, for example, fails to improve the heat stability or odor of said oils. Thus, it is theorized that the oils have a buffering capacity probably due to esters and other organic complexes which makes neutralization alone ineffective.

As indicated above, the first step in our process is oxi dation of the epoxidized oils. Any of the conventional 3 ,150,153 Patented Sept. 22, 1964 methods for oxidizing organic materials can be employed. Thus oxygen, air or other oxygen containing gas can be bubbled through the oils; or peroxides, such as hydrogen peroxide, can be used to treat the oils. Other oxi dants and oxidation catalysts can be employed as well as combinations thereof. Obviously, the reaction conditions will vary somewhat with the various oxidizing agents and the particular oils being oxidized. It is only necessary that the oils be oxidized to a sufficient degree to facilitate subsequent neutralization with alkaline mate rials. And, of course, the combination of the oxidation and neutralization must be sutiicient to improve the heat stability and/ or odor of the epoxidized oils. When using oxygen, air or other oxygen containing gas, the oxidation is preferably carried out at temperatures of about 50 to C. for about one hour to 15 hours or more. Oxida tion with hydrogen peroxide is preferably accomplished at temperatures of about 25 to 150 C. for about 30 min utes to five hours or more. It is also preferred to use aqueous hydrogen peroxide (i.e., about 20 to 70% by The oxidation can be accompanied by or followed by water washing. Thus, the epoxidized oils can be oxidized and water washed in a series of steps or the oxidation can be completed and then the oxidized oil can be water Washed. Of course, our process can be carried out with out water washing. However, it is preferred to use such treatment to remove some of the oxidation products and/ or lower the acid values of the oxidized oils to some degree.

After completion of the oxidation or oxidation and water washing steps, the oil is neutralized. Such neutrali zation is preferably carried out by contacting the oxidized oils with aqueous alkali or alkaline earth metal hydroxides or oxides, such as aqueous sodium hydroxide, potassium hydroxide, calcium hydroxide and the like. Other alka line treating agents can also be used, i.e., carbonates, bi carbonates and the like. Again the degree of neutralization is difiicult to define precisely. However, it should be sufficient to lower the acid value appreciably, preferably to 0.1 or less. Additionally, the combination of the oxidation and neutralization steps must improve the heat stability and/or odor of the epoxidized oils.

The oxidized and neutralized oil, if necessary, can be water washed, stripped to remove any remaining Water or other volatile materials and/ or filtered. The filtration step can be aided by the addition of a filter aid, such as I-lyfio Supercel, Filtrol Grade I, and the like.

The epoxidized oils, treated according to our process, are particularly useful as plasticizers for various resinous materials. Such oils have excellent heat stability and do not have otiensive odors.

The following examples serve to further illustrate the present invention without limiting the same thereto.

Example I Into a stream cone was placed 300' g. of an epoxidized oil having the following analysis:

Oxirane oxygen percent 6.9 Iodine value 1.3 Acid value (g. KOH/IOOO g.) 0.8 Sap. No 182.4 Viscosity (Gardner) 0 Said oil was prepared by treating alkali refined soybean oil with non-aqueous peracetic acid. Air was drawn through the oil for one hour while the cone was heated under full steam pressure (about 98 0). Then five g. NaOH dis solved in approximately 50 ml. water was added and the resulting mixture was heated and stirred to effect contact of the NaOH with the air oxidized oil. After allowing the mixture to stand for approximately 12 hours, the

Color (Gardner) Water was stripped off using a water vacuum pump. To 100 g. of the product was added one g. of Filtrol Grade I (an acid activated montmorillonite clay). The productfilter aid mixture was then heated for 15 minutes on a steam bath and filtered. The resulting epoxidized oil had virtually no odor and the following analysis:

Oxirane oxygen percent 6.9 Iodine value 1.4 Acid value (g. KOH/ 1000 g.) 0.06 Sap. No 180.8 Viscosity (Gardner) M-N This example shows that the process of our invention can be used to produce an epoxidized oil of very low acid value which is substantially odorless. The oil before treatment had an offensive odor similar to acetaldehyde.

Example [I To a 30 gal. glass kettle were added 83.0 lb. water and 123.8 lb. of an epoxidized oil having the following analysis:

Oxirane oxygen percent 6.9 Iodine value 1.9 Acid value (g. KOH/ 1000 g.) 0.44 Sap. No 183.8 Water content percent 0.03 Viscosity (Gardner) N Color (Gardner) 1 (1) About 105 lb. water added.

(2) Kettle temperature adjusted to about 8090 C.

(3) Air bubbled into bottom of kettle with agitation for approximately 15 minutes.

(4) Oil-water mixture allowed to settle for about one hour.

(5) About 105 lb. water drained oil.

This treatment was repeated times and then 304.6 g. aqueous NaOH (50% by weight NaOH) was added. The mixture was agitated for one hour at 90 C. The acid number was reduced from 0.49 to 0.13. The water was then stripped from the oil and the oil was filtered with the aid of lb. Hyfio Supercel. There was obtained 106.0 lb. epoxidized oil having the following analysis:

Oxirane oxygen percent 6.9 Iodine value 1.6 Acid value (g. KOH/1-000 g.) 0.05 Sap. No 180.6 Water content percent 0.06 Viscosity (Gardner) M Color (Gardner) 1 The treated epoxidized oil also was substantially odor free. The heat stability of the epoxidized oil before and after treatment by our process was also measured by heating the respective samples for two hours at 350 F. and also 'for 16 hours at 165 C. Results are as follows:

Two hours at Sixteen hours at Untreated Treated Untreated Treated Oxirane Oxygen, percent- 1 6. Color, percent Transfer 37.

The data of this example clearly shows that the heat 4 stability and odor of epoxidized oils can be materially improved by the process of the present invention.

Example III To a flask fitted with a stirrer and thermometer were added 124 g. aqueous H 0 (30% by weight) and 1000 g. of an epoxidized oil having the following analysis:

Oxirane oxygen percent 7.0 Iodine value 2.0 Acid value (g. KOH/IOOO g.) 0.57 Sap. No 181.0 Water content percent 0.03 Viscosity (Gardner) L Color (Gardner) 1 Said oil was prepared by treating salad-grade soybean oil with non-aqueous peraeetie acid. The mixture was stirred for 2 /2 hours at a temperature of 60 C. One 1. of water was then added, the stirring was continued for an additional 1 /2 hours, and then the reaction mixture was transferred to a separatory funnel and allowed to stand for about 12 hours. Approximately one 1. of water was drained oil and then the oil was Washed two more times using one 1. of fresh water for each wash. The bulk of the water was removed after the third wash and two g. caustic soda was added to the oil phase. After neutralization, the oil was again washed with one 1. of water and stripped at 60 C. with a water jet in a falling film evaporator. The oil was then filtered (added 50 g. Hyflo Supercel). The product had the following analysis:

Oxirane oxygen percent 6.8 Iodine value 1.8 Acid value (g. KOH/ 1000 g.) 0.0 Sap. No. 180.3 Water content percent 0.11 Viscosity (Gardner) 0 The above example shows that the epoxidized oil can be oxidized by H 0 and that subsequent neutralization will lower the acid value to 0.0. Additionally the treated oil had no offensive odors.

Example IV Two hundred and three lbs. of the same epoxidized oil treated in Example III and 22 lb. aqueous H 0 (35% by weight) were added to a gallon kettle. The reaction mixture was heated to 58 C. with agitation. After 1 /2 hours, 200 lb. Water (temperature 57 C.) was added. The kettle was allowed to stand overnight and then enough Water to fill the kettle was added. Most of the water was drained off after a settling period of about three hours and the oxidized oil was washed four more times by adding water to fill the kettle, allowing the mixture to settle and draining off the Water. The oil was neutralized by adding 181.6 g. NaOl-l (equal amount of water) and agitating the mixture for ten minutes. About 900 lb. water was added at 60 C. This wash water was drained oil, the oil was stripped at 68 C. under vacuum and then filtered. There was obtained 179 lb. of treated epoxidized oil having the following analysis:

Oxirane oxygen percent 7.0 Iodine value 2.1 Acid value (g. KOH/ 1000 g.) 0.08 Sap. No. -I 181.0 Water content percent 0.1 Viscosity (Gardner) P Color (Gardner) 1 The oil had a materially improved odor and had heat stability properties similar to the oil of Example II.

It is to be understood that the invention is not to be limited to the exact details of operation or the exact compositions and materials described, as obvious modifications and equivalents will be apparent to those skilled in the art and the invention is to be limited only by the scope of the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The process comprising oxidizing an oil consisting essentially of esters of epoxidized fatty acids derived from unsaturated fatty acids containing from about 8 to 22 carbon atoms and neutralizing the resulting oxidized oil With an aqueous alkaline material, the oxidizing and subsequent neutralizing being sufficient to improve the heat stability and odor of the oil.

2. The process of claim 1 wherein the oxidizing is accomplished by the use of at least one oxidizing agent selected from the group consisting of oxygen, free oxygen containing gases and peroxides.

3. The process of claim 2 wherein the oxidizing agent is air and the oxidation is carried out at temperatures of about 50 to 150 C. for about 1 to 15 hours.

4. The process of claim 2 wherein the oxidizing agent is hydrogen peroxide and the oxidation is carried out at temperatures of about 25 to 150 C. for about 30 minutes to 5 hours.

5. The process of claim 1 wherein the neutralizing is accomplished by the use of an aqueous alkaline material containing at least one neutralizing agent selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides and alkaline earth metal oxides.

6. The process of claim 1 wherein at least one water washing step is employed at some point in the process subsequent to the oxidizing step.

7. The process comprising oxidizing epoxidized soybean oil, said oil having been prepared by reacting soybean oil with non-aqueous peracetic acid, and neutralizing the resulting oxidized oil with an aqueous alkaline material, the oxidizing and subsequent neutralizing being sufiicient to improve the heat stability and odor of the epoxidized soybean oil.

References Cited in the file of this patent UNITED STATES PATENTS 2,810,733 Greenspan Oct. 22, 1957 2,822,368 Rowland et a1 Feb. 4, 1958 2,956,975 Greenspan Oct. 18, 1960 3,040,076 Seidel et a1. June 19, 1962 FOREIGN PATENTS 757,407 Great Britain Sept. 19, 1956 847,343 Great Britain Sept. 7, 1960 OTHER REFERENCES Greenspan et al.: Ind. Eng. Chem, vol. 45, pages 2722 26 (1953).

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0 3 150, 153 September 22 1964 Stuart A. Harrison et a1,

n the above numbered pat rtifiedthat error appears i rs Patent should read as It is hereb ce tion and that the said Lette ent requiring correo corrected below.

In the heading to the printed specification lines 2 and "STABILITY OF EPOXIDIZED OILS BY 3 title of invention, for OXIDATION AND NATURALIZATION" read STABILIZATION OF EPOXIDIZED OILS BY OXIDATION AND NEUTRALIZATIO column :2

line 56 for "stream" read steam Signed and sealed this 12th day of January 1965.

(SEAL) Attest:

EDWARD J. BRENNER ERNEST W. SWIDER Attesting Officer Commissioner of Patents

Claims (1)

1. THE PROCESS COMPRISING OXIDIZING AN OIL CONSISTING ESSENTIALLY OF ESTERS OF EPOXIDIZED FATTY ACIDS DERIVED FROM UNSATURATED FATTY ACIDS CONTAINING FROM ABOUT 8 TO 22 CARBON ATOMS AND NEUTRALIZING THE RESULTING OXIDIZED OIL WITH AN AQUEOUS ALKALINE MATERIAL, THE OXIDIZING AND SUBSEQUENT NEUTRALIZING BEING SUFFICIENT TO IMPROVE THE HEAT STABILITY AND ODOR OF THE OIL.