US2318749A - Production of fat-soluble vitamin concentrates - Google Patents

Description

Patented May 11, 1943 UNlTED PRODUCTION OF FAT-SOLUBLE VET s t 1|] CONCENTRATES Jersey v No Drawing. Application August 2, 1940,

7 Serial No. 350,166 .19 Claims. (c1. 167-81) The present invention relates in general to the treatment of fatty materials and in particular to a process for recovering the unsaponiflable fraction from a saponiiiable fat or oil.

Heretoi'ore various processes have been proposed and used for eflecting the separation and recovery of the unsaponiflable fraction from fats and oils. Such processes are particularly important in the production of the fat-soluble vitamin concentrates from vitamin-bearing oils and'fats. Generally speaking, these prior processes involve the steps of treating the oil or fat with a saponifying agent to convert the fatty acids and glycerides into soap, leaving the unreacted unsaponifiable fraction admixed with the soap. Great difficulty has been experienced in separating the unsaponifiable fraction from the soap by solvent extraction due to the physical characteristics of the soap and the manner in which the unsaponii'lable fraction was physically occluded in or coupled with the soap. In the step of extracting the soap with various solvents I for the unsaponifiable fraction, obstinate emulsions were formed, thus defeating the purposes of this step. Moreover, the physical structure of the soap was such that the solvent was prevented from coming into intimate contact with a large portion of the unsaponifiable fraction which was occluded in the soap.

In an attempt to alleviate the foregoing dimculties, a process was devised wherein a viscoussolid soap was produced by the use of an aqueous alcoholic solution of potash as the saponifying agent. Here again, the step of properly extracting the saponified mass with solvent gave rise to many obstacles primarily due to the fact that the solvent did not come into intimate contact with the unsaponiflable fraction, notwithstanding the viscous nature of the soap. In order to recover 70% to 80% of the original vitamin A and D content by the foregoing process, it was necessary to extract the viscous-solid soap at least eight to twelve times, thus materially adding to the cost of production by virtue of the labor involved and large quantities of solvent employed.

In a further attempt to reduce the cost of producing fat-soluble vitamin concentrates, it was proposed to saponify the original oil or fat in the presence of solvents such as acetone or pentane. This process failed to solve the problem as the extraction step continued to be a major problem in view of the character of the soap formed, and the yield of the recovered vitamins remained relatively low.

The general object of the present invention is to alleviate the disadvantages of the prior art processes for separating the unsaponii'iable fractionirom fats and oils.

A specific object-oi the'invention is to provide an improved process of producing fat-soluble vitamin concentrates from vitamin-bearing oils and fats, whereby the vitamin recovery is substantially complete.

Another object of the invention is to increase the efliciency and reduce the cost of producing fat-soluble vitamin concentrates from their nat- I ural sources.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

In accordance with its broader aspects, the

process of the invention involves the recovery or separation of the unsaponiiiable' fraction from animal, vegetable or marine fats and oils by the saponification method, wherein the moisture content of the soap formed is controlled in such a manner as to render at least a major portion pi the same soluble in hydrocarbon or halogen-. ated hydrocarbon solvents at one stage of the process, and insoluble in such solvents at a subsequent stage in the process. Generally speaking, the oil or fat to be treated is subjected to treatment with allzali of a calculated concentration to yield a soap having a moisture content of less than 20%. This saponiilcation step may be carried out with or without the presence of a.

solvent for the oil or fat. Upon completion of the saponiilcation process, which is preferably carried on in an inert atmosphere, particularly when.

vitamin A is present, the soap formed is taken up and dissolved in a hydrocarbon or halogenated hydrocarbon solvent. The step of dissolving the soap in the solvent is preferably aided and accelerated by means of heat to produces. substantially true solution, which in most cases is brilliantly clear.

The soap-solvent mass is thereafter cooled to room temperature, at which point slight separa-' tion of soap from the solvent solution is efiected. At this point, sufilcient Water is added to increase the moisture content of the soap to above 20%, whereby the soap is precipitated out in a granular form. The solvent solution of the unsaponiflable fraction is now free from soap and is removed from the separated soap, the latter being then washed with additional fresh solvent to wash the same free from any solvent solution of the unsaponifiable fraction adherin thereto. The unsaponifiable fraction is recovered from the solvent according to the usual means, which normally embraces distilling the solvent oil under reduced pressure and preferably in the presence of an inert atmosphere when vitamin A is present. The foregoing process of the invention is particularly adapted for commercial practice in view of the reasonable cost involved, as well as the high yield of the unsaponifiable fraction, which normally runs in the order of about 95% to 100% of that present in the original oil.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others thereof. which will be exemplified in the process hereinafter disclosed, and the scope of the invention will be indicated in the claims.

In carrying out the process of the invention, any suitable saponiflable oil or fat from which the recovery of the unsaponifiable fraction is desired. may be used in effectuating the purposes of the invention. The unsaponiflable fraction of various animal, vegetable and marine oils and fats contains valuable byproducts when separated from their fatty vehicle. Many oils contain sterols and more particularly the fat-soluble vitamins A, D and E and pro-vitamin A. While the present invention may be applied to various oils, it has particular value in the production of the fat-soluble vitamin concentrates which are derived from fish liver oils and certain animal and vegetable oils; the vitamin A and/or D-cOntaining oils include. among others, the oils produced from various'flsh andtheir livers, such as cod, sardine, halibut, tuna, shark, dogflsh, ling cod, pollack, sword, pilchard, whale and other fish. Pro-vitamin A may be concentrated according to the invention from various vegetable ,oils, such as palm oil and carrot oil, and vitamin E may be recovered from wheat germ, rice bran and like oils. The unsaponifiable fraction of various other {oils includingrice bran oil, soya bean oil and the like are valuable products in and 'of themselves and may be recovered readilvin accordance with the process of the invention.

The oil or fat to be treated according to the process of the invention is saponifled by means of an alkaline agent in an amount at least equal to the stoichiometrical quantity required to react completely with the saponifiable portion of the oil or fat, an excess of the agent being preferably employed to insure complete saponiiication of the oil or fat. The salient feature of the invention re sides in controlling the saponificatlon so as to obtain a soap'having a moisture content of not more than 20% and preferably not more than about 18% or 19%. This upper limit on moisture content of the soap may be varied slightly dependin primarily upon the solvent to be used; the 11m portant factor being that the moisture content should not be above that point at which the soap will not properly dissolve in the organic solvent used. It, has been found that when ethylene dichloride is used as the solvent, a moisture content of about 20% will be tolerated. In order to safeguar the formation of a substantially true solution of the soap in ethylene dichloride, it is preferred to control the moisture content to a value at or below 18% or 19%, a shitable range being about 12% to 19%. As may be expected, the lower the moisture content, the more soluble the soap becomes in the solvent; however, it is desirable that the soap have, a moisture content of about 12% up to 19% as the soap in such a condition will more readily absorb the water added during the precipitation step than a soap having a moisture content of less than 12%. The glycerin obtained in the saponification step remains in the soap and serves to aid the hydration thereof during the precipitating step.

A concentrated aqueous solution of caustic soda or potash may be used as the saponifying agent, the latter being highly preferred as the potash soaps are more readily dissolved in the aforementioned type solvents. The alkali is preferably used in a concentration of about 45% or more. In order to accelerate the saponification reaction, the use of a relatively small quantity of a saponifying catalyst is advantageous; such catalysts preferably comprise the lower aliphatic alcohols or mixtures thereof, such as methanol, ethanol, isopropanol, etc., isopropanol being preferred. The saponifying catalyst may be added to the concentrated aqueous caustic solution, but it is preferred to add the same to the oil or fat prior to the addition of the alkali solution, due to the usual manufacturing set-up wherein the alkali is fed in from a separate system. Saponiflcation of the oil or fat may also be caused to take place in the presence of a hydrocarbon or halogenated hydrocarbon solvent, the quantity thereof preferably being less by weight than that of the oil or fat.

An alkali metal soap having a moisture content of 20% or below may be dissolved in a hydrocarbon of halogenated hydrocarbon solvent to obtain a true solution or a mixture approaching a true solution. In so dissolving the soap, the solvent comes into intimate contact with the whole of the unsaponiflable fraction inasmuch as both the soap and the unsaponiflable fraction are rendered substantially completely soluble in the solvent. In efiecting this solution, it is preferable to heat the mixture to a temperature sumcient to dissolve at least a major portion of the soap, which temperature is preferably below the boiling point of the solvent. It has been found that a temperature of about 50 to 70 C. results in the proper solution of the soap and the unsaponiflable fraction in the selected solvent- In preparing the solution of the soap and the unsaponiflable fraction, halogenated hydrocarbon solvent or mixtures thereof may be employed, it being highly preferred, however, to use a halogenated hydrocarbon solvent, and particularly ethylene dichloride. Other solvents, such as trichlorethylene, heptane, octane, methyl cyclohexane, carbon tetrachloride and the like, may also be used, but

far superior results are obtained by the use of ethylene dichloride. The quantity of solvent usedmay lie within the ratio range of 3 to 10 parts by weight to each part by weight of fat or oil treated.

After the solution of the soap and the unsaponifiable fraction in the selected solvent has been obtained, suflicient water is stirred into the solution to raise the moisture content of the soap to above 20%, which renders the soap in its more hydrous form insoluble in the solvent, thereby effecting precipitation of the soap. When ethylene dichloride is used, for example, the density of the soap is less than that of this solvent and consequently the soap rises to the surface of the solvent solution of the unsaponiflable fraction. Curiously enough, the soap separates in a somewhat granular form, which does not occlude any of the solvent solution of the unsaponlfiable fraction, the major portion of the unsaponifiable fraction remaining in the solvent solution. Obvlously, however, some of the solvent solution of the unsaponiflable fraction adheres to the surface of the granular soap particles, and after the a suitable hydrocarbon or i atlases washed anywhere from one to five times with fresh solvent to insure the complete recovery of the unsaponiflahle fraction. The amount of water added in the precipitation step should be controlled so that the moisture content of the soap is raised to a point preferably within the range of about 22% to 26%. it the moisture content of the soap is raised much over 28%, the desired granular formation does not rmult. It has been found that 95% to 100% of the un saponiflable fraction originally present in the fatty material treated is recovered, which involves a tremendous advance over the heretofore known processes of recovering the unsaponiflable fraction from oils and fats.

The process of the invention is particularly valuable in the manufacture of tat-soluble vitamin concentrates, particularly oils containing vitamins A and/or D and oils containing provitamin A and oils containing vitamin E. In order to insure complete recovery when vitamin A-containing oils are treated in accordance with the process of the invention, it is desirable to guard against destructive oxidation of vitamin A by effecting the saponification and extraction steps in an inert atmosphere which may readily be provided by bubbling nitrogen gas or carbon dioxide gas through the mass during the process.

For a fuller understanding of the nature and objects of the-invention, reference should be had to the following examples which are given merely to further illustrate the invention and are not to be construed in a limiting sense, all parts vgiven being by weight:

Example I formed. Nitrogen gas was passed through the oil-alcohol-caustic alkali mixture during the stirring operation. The soap mixture was insulated at the reaction temperature for about 12 to 15 hours. 400 parts of ethylene dichloride were added to the soap mass, and while stirring, the mixture was heated for about 15 minutes at 80 to 70 C. At this temperature substantially all the soap was soluble in the solvent to give a bril liantly clear solution. The soap-solvent mass was then cooled to room temperature and stirring continued. 011 ceasing stirring, a slight separa tion of soap from solvent occurred. The soap mass at this stage has a moisture content of about 17%. The stirring was continued and water added until substantially all the soap rapidly separated in a granular condition to the surface when stirring was ceased. The soap at this stage contained about 23.5% moisture. The clear solvent layer was removed and the soap mass washed with four additional portions of fresh ethylene dichloride. The combined solvent extract fractions were placed in a distillation chamber and the solvent removed under reduced 200 parts of dog fish liver oil containing 20,400

units vitamin A per gram were admitted with 8 parts of isopropanol and suiilcient 48% q eous KOH to completely saponify the oil, plus a 15% excess oi KOH on the basis of the saponiflcation value. The mixture in an amosphere 01 nitro-- gen gas was stirred untila heavy, thick mass resulted. The mass was insulated at the reaction temperature and allowed to stand for 3 to d temperature was increased to 60 to 65 C., at

which stage a high percentage of the soap was dissolved in the hot solvent while stirring. After cooling to room temperature, at which time stirring was discontinued, slight soap separation resulted. The moisture content of the soap mass at this stage was about 14%. Water was then added with stirring until the soap separated in a granular particle formation leaving a brilliantly clear solvent layer. The soap at this point contained about 25% moisture. The solvent layer was removed as in Example land the soap mass washed five additional times with iresh solvent. The yield of unsaponiflable fraction was 082%.

Exam le II! cient saw. aqueous non added to completely" saponiiy the oil. stirring of the mixture was continued until a heavy, thick mass resulted. The mass was then insulated to retain the heat of reaction and permitted to stand for 5 hours. after which 800 parts of ethylene dichloride were added with stirring. The temperature of the mass was then raised to about 65 C., whereupon a substantially true solution of the mass in the solvent resulted. Upon cooling to room temperature, slight soaps separation occurred, the moisture content of the soap now being about 15%. Sufdcient water was then added with f stirring to raise the moisture content of the soap to about 22%, whereupon granular soap separated out leaving a clear solvent solution of the unsaponifiable fraction. The solvent layer was removed and the soap washed four times with fresh ethylene dichloride. The solvent solution of the unsaponinable fraction and the washings were combined and subjected to distillation under reduced pressure in an inert atmospherev The yield of the unsaponinable of nitrogen. fraction which contained l,5i0,000 U. S. P. units of vitamin A/gm. and 14,900 units of vitamin D parts of a mu liver oil containing moss units vitamin A and 88,500 units vitamin D per gram were mixed with 3 parts oi. isopropanol and 25 parts of ethylene dichloride. While agitating the mixture, 54% aqueous KOH in an amount sumcient to completely saponify the oil (plus a 15% excess) was added thereto. The stirring was continued until a thick mass resulted which was then insulated at the reaction temperature and allowed to stand for four hours. Stirs-m was then continued and 400 parts of ethylene dichloride were added. The mixture was then heated to 60 to 65 C. for 15 minutes, under which conditions substantially all the soap was miscilote with the hot solvent. The soap-solvent mass was then cooled to room temperature, whereupon a slight separation of soap i'rom solvent resulted;

the moisture content of the soap at this stage was about 15% Stirring was then continued and water added until soap separated out in a somewhat granular form. The solvent solution of the unsaponiflable fraction, which was brilliantly clear, thus indicating the absence of dissolved soap, was removed from the soap, and the latter was re-washed with 5 additional batches of fresh ethylene dichloride. The solvent washes containing the unsaponiflable fraction were filtered and the solvent removed under reduced pressure in an inert atmosphere of nitrogen gas. The unsaponiflable fraction contained 1,$40,000 units vitamin A and 1,000,000 units vitamin D per gram. The yield was 95.6%.

From the foregoing description of the process of the invention, it is apparent that the control of the moisture content in the soap involves an important factor as far as the successful practice thereof is concerned. In the so-called dissolving step, it is not, in all cases, necessary to completely dissolve the whole of the saponified mass in the true sense of the expression as the dissolution of a major portion of the soap results in successful and eflicient recovery of the unsaponifiable fraction.

Since certain changes may be made in carrying out the above process without departing from the scope of the invention, it is intended that all matter contained in the above description shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention herein clescribed, and all statements of the scope of the invention, which as a matter of language might be said to fall therebetween.

Having described our invention. what we claim as new and desire to secure by Letters Patent, is:

1. In a process of recovering the unsaponiflable fraction from a fatty m'aterial selected from the class consisting of fats and oils, the steps which comprise dissolving a soap of such fatty material containing unsaponifiable matter and less than 20% moisture in a solvent selected from the group consisting of hydrocarbons and halogenated hydrocarbons and adding sufilcient water to the mass to raise the moisture content of the soap to a point abov 20% to induce precipitation of the soap from the solvent.

2. In a process of recovering the unsaponifiable fraction from a fatty material selected from the class consisting of fats and oils, the steps which comprise dissolving a soap of such fatty material containing unsaponifiable matter and less than 20% moisture in a chlorinated hydrocarbon solvent and adding sufilcient water to the mass to raise the moisture content of the soap to a point above 20% to induce precipitation of the soap from the solvent.

3. In a process of recovering the unsaponifiable fraction from a fatty material selected from the class consisting of fats and oils, the steps which comprise dissolving a soap of such fatty material containing unsaponifiable matter and less than 20% moisture in ethylene dichloride and' adding sufiicient water to the mass to raise mixing a soap of a fat-soluble vitamin-containing fatty material containing 12% to 19% moisture with a solvent selected from the group consisting of hydrocarbons and halogenated hydrocarbons, heating the mixture to dissolve a major portion of the soap and adding sufficient water to the mass to raise the moisture content of the soap to about 22% to 26% to cause precipitation thereof.

5. In a process of producing fat-soluble vitamin concentrates, the steps which comprise admixing a fish liver oil soap containing 12% to 19% moisture with a solvent selected from the group consisting of hydrocarbons and halogenated hydrocarbons, heating the mixture to dissolve a major portion of the soap and adding suflicient water to the mass to raise the moisture content of the soap to about 22% to 26% to cause precipitation thereof.

6. In a process of producing fat-soluble vitamin concentrates, the step which comprises admixing a fish liver oil soap containing 12% to 19% moisture with ethylene dichloride, heating the mixture to dissolve a major portion of the soap and adding sufllcient water to the mass to raise the moisture content of the soap to about 22% to 26% to cause precipitation thereof.

7. In a process of separating the unsaponiflabie fraction from a fatty material, the steps which comprise saponifying a fatty material selected from the class consisting of fats and oils with an alkali to produce a soap having a moisture content of less than 20%, dissolving the saponified mass in a solvent selected from the group consisting of hydrocarbons and halogenated hydrocarbons and adding water to the solution to eiiect precipitation of the soap.

8. In a process of separating the unsaponiflable fraction from a fatty material, the steps which; comprise saponifying a fatty material selected from the class consisting of fats and oils with an alkali to produce a soap having a moisture content of less than 20%, dissolving the saponified mass in ethylene dichloride and adding water to the solution to effect precipitation of the soap.

9. A process of producing a fat-soluble vitamin concentrate, which comprises saponifying a fatty material containing a fat-soluble vitamin by means of an alkali in such a manner as to produce a soap having less than 20% moisture, dissolving the mass in a solvent selected from the group consisting of hydrocarbons and halogenated hydrocarbons, adding sufiicient water to raise the moisture content of the soap to over 20% to effect precipitation of the soap in a granular form and separating the solvent solution of the unsaponifiable fraction from the precipitated scan.

10. A process of producing a fat-soluble vitamin concentrate, which comprises saponifying a fat-soluble vitamin-containing material with an aqueous solution of potash, the concentration of the potash solution being such as to yield a soap having a moisture content of less than 20%, admixing the saponified mass with ethylene dichloride, heating the mixture to dissolve a major portion of the soap, adding sufficient water to raise the moisture content of the soap to a point above 20%, whereby precipitation of the soap is effected, and separating the solvent solution of the unsaponifiable fraction from the soap.

11. A process of producing a fat-soluble vitamin concentrate, which comprises saponifying a fat-soluble vitamin-containing material with an aqueous solution of potash, the concentration of the potash solution being such as to yield a soap having a moisture content 01 about 12% to 19%, admixing the saponifled mass with ethylene dichloride, heating the mixture to dissolve a major portion of the soap, adding sufllcient water to raise the moisture content of the soap to a point within the range of 22% to 26%. whereby precipitation of the soap is effected and separating the solvent solution of the unsaponiflable fraction from the soap.

12. The process of producing a fat-soluble vitamin concentrate, which comprises saponiiying, in the presence of a relatively small amount of an alcoholic saponifying catalyst, a fish liver oil with an aqueous potash solution 01 a concentration to yield a soap having a moisture content of about 12% to 19%, admixing the saponiiled mass with a chlorinated hydrocarbon solvent, heating content of the soap to about 22% to 26%, where by the soap is precipitated out in a granular form, and separating the resulting solvent solution of the fat-soluble vitamin fraction from the soap.

13. The process oi producing a fat-soluble vitamin concentrate, which comprises saponiiying, in the presence of a relatively small amount oi isopropanol, a fish liver oil with an aqueous potash solution of a concentration to yield a soap having a moisture content oi'about 12% to 19%, admining the saponifled mass with ethylene dichloride, heating the mixture to dissolve a major portion of the soap, adding sufficient water to raise the moisture content of the soap to about 22% to 26%, whereby the soap is precipitated out in a granular form, and separating the resulting solvent solution of the fat-soluble vitamin fraction from the soap.

14. The process of producing a fat-soluble vitamin concentrate, which comprises saponiiying, in i the presence of a relatively small amount of an alcoholic saponifying catalyst, a vitamin E-containing oil with an aqueous potash solution of a concentration to yield a soap having a moisture content of about 12% to 19%, admixing the saponlfied mass with a chlorinated hydrocarbon solvent, heating the mixture to dissolve a major portion of the soap, adding sufllcient water to raise the moisture content of the soap to about 22% to 26%, whereby the soap is precipitated out in a granular term, and separating the resulting solvent solution of the fat-soluble vitamin irac tion from the soap.

15. The process of producing a fat-soluble vitamin concentrate, which comprises saponifying in the presence of a relatively small amount of an alcoholic saponifying catalyst, a pro-vitamin A- containing oil with an aqueous potash solution of a concentration to yield a soap having a moist ture content of about 12% to 19%, admixing the saponified mass with a chlorinated hydrocarbon solvent, heating the mixture to dissolve a major portion of the soap, adding sufilclent water to raise the moisture content of the soap to about 22% to 26%, whereby the soap is precipitated out in a granular iorm, and separating the resulting solvent solution of the fat-soluble vitamin fraction from the soap.

solution of a concentration to yield a soap having a moisture content of about 12% to 12%, admixing the saponified mass with a chlorinated hydrocarbon solvent, heating the mixture to dissolve a major portion of the soap, adding suiiicient water to raise the moisture content of the soap to about 22% to 26%, whereby the soap is precipitated out in a granular form, and separating the resulting solvent solution of the fat-soluble vitamin fraction from the soap.

17. The process of producing a fat-soluble vitamin concentrate, which comprises saponifying, in the presence of a relatively small amount of an alcoholic saponiiying catalyst, at fat-soluble vitamin-containing fatty material having a lesser quantity by weight of ethylene dichloride dissolved therein with an aqueous potash solution oil a concentration to yield a soap having a moisture content oi. about 12% to 19%, admixing the saponifled mass with a chlorinated hydrocarbon solvent, heating the mixture to dissolve a major portion 01 the soap, adding suiflcient water to raise the moisture content of the soap to about 22% to 26%,' whereby the soap is precipitated out in a granular form, and separating the resulting solvent solution of the fatssoluble vitamin fraction from the soap.

18. The process of producing a fat-soluble vitamin concentrate, which comprises saponii'ying, in the presence of a relatively small amount of an alcoholic saponiiying catalyst, a fish liver oil having a lesser quantity by weight of ethylene dichloride dissolved therein with an aqueous potash solution of a concentration to yield a soap having a moisture content of about 12% to 19%, admixing the saponiiied mass with a chlorinated hydrocarbon solvent, heating the mixture to dissolve a major portion of the soap, adding sufficient water to raise the moisture content of the soap to about 22% to 26%, whereby the soap is precipitated out in a granular form, and separating the resulting solvent solution of the fat-soluble vitamin fraction from the soap.

19. The process of producing a fat-soluble vitamin concentrate, which comprises saponliying, in the presence of a relatively small amount of isopropanol, a fish liver oil with an aqueous potash solution of a concentration to yield a soap having a moisture content of about 12% to 19%, while passing an inert gas through the mass, admixing the saponifled mass with ethylene dichloride,

heating the mixture to dissolve a major portion l from the soap.

LORAN 0. 31311011. HOWARD B. COLMAN.