US2510379A - Preparation of break-free glyceride oils - Google Patents

Description

Patented June 6,.,1950

PREPARAIHQN oFL-BREA-KFREE GLXGERIDEDILS Aloger'l Christensen, Milwaukeefwis., assigner toPttslugliPl'ate' Glass Company, Allegheny "'Couiity,'Pa.,a corporationfof Pennsylvania "13 Claims.

. '1 LThe present'inveitionrelates vto therlning of crudezor but partially rened glyceri'de ko'ils Such as soybeanboil, lin'seed oil, cottonsee'fd oil, corn oil or the'l'ike and it has particular relation to the refining ofsuch'oils for purposes of removing the break constituents thererom.

One object of the invention is to provide a process of treating 'glyceride'oils of the foregoing types gior purposes of .removing or transforming break. constituents-which. process `is..accompanied '-1 by ybut.. s1ight losses. of the. constituents desirable in the oil.

u .Asecond object of,the,invention`.is .tolprovidera process .=.of .treating .glyoeride oils `containing fbreak` constituents, or other ,objectionable con- -stituents 1in. order to ieliminatasuch constituents for. renderv themoinnocuous, .which .cansbeieffected inea` minimum. of `time .Witha g minimum of...ap vparatus and. in which .there but llittle -ormo degradationof..the.oil.treated. 1

-A.. 4.third obj ect e. of .ftheiinvention to provide a process of .treating glyceride .oils containing breakl or-:gum `constituents -to obtain .a product which Withoutisubstantial .losslofi glycerides, Acan he; employed for` such purposelas .the 4formation ofoalkydstyp e` resins on fortfnrthenextraction Iwith selected polar solvents in. order. -toiractionate the oil into highly unsaturatedwand highly saturated portions of light color.

1A 4fourth :oloioot .of fhoinvonion .I is to 1 provido a. process- .of .treating .orrido oil oon-taining .break oonstituoots lsu/ch lecithin ,or .Similar .phosohatdos and .oolorinemattor `to:providelvvfho,.1.1t substantial loss of glycerides, .aiproduct which .can thonroasilvbo bleached :forpurlooses offromoving or otherwiseeliminating the color constituents i therefrom.

. vvThese and other A objects of thel invention will be xapparent from consideration of; the following specification and the .appendedclaims. Glyceride oils such assoybean oil,.1inseedoil, cottonseed; oil, corn `oil and the like as obtained by conventional methods of removal. from the seeds .constituting the source thereofVinclude various4 constituentsf-such as.. .gums or breakt constituents Whichflhave ia tendency .-toseparate fout andrsform .a .iT-lock, .especially .Whensthe `aoil heated. Y'The Aoil ^also usually. includes .other :objectionable :materials such cas .fcoloring `matter. For some purposes and with some gradespffol, these latter constituents :maynot be particularly objectionable. However, if anoil of light color isirequired, theyjmayjreguire treatment inzorder to geffect;removartnereof.

I"The convent na1"^test 'for break is known as ApplicationAugust 31, 194s, Serial No- 47,130

the yGardner test.V vIt comprises adding Aa few frirops 'of aqueoushydrochloric acifd and heating the`'il1to`550WF. "Formation of a precipitatefis a positivr'eV test. The precipitatemaybeltered o, :washed free 4ofoil with carbon tetrachloride and `weighed to ldeterrnine ipercent of Gardner break. Tnemetnqd isignownas A. 0.o.-

'The'ccnventionalymethod oftreating glyceride oils in..order tof/remove: break and` to improve the coloring linvolved, most usuallytreatment" with a strong'aljkaii such assodiu'rnl hydroxide 4in Vconsjderahierquantities; or vby.tdegurmning 'unitari/atar. The alkali reacts With the "free `fatty '-acids; the

1 break Yc'oristiti'ie,ntsaridto's'orne'extentvvitli the 'glycerdes, producingsoaps 'which' loyA appropriate cooling ,andsettling technique can' be collected as jan Aunder layer called roots. *Tvheefoots and the oiljin"conventionalipracticeA areseparated by jdecaritati'on,'jcentrifugationor otherappropriate technique. With Nthe i'foots, vis entrapped #consilderable'uam'ounts'o'f' gooclo'il. The foots orby- 'product can jbe jsol'rl *only-ata greatly wreduced price.

Simple degunirning, i or treatment with 'Water 'may `also be' employed* torenne the "oil, butit results" 'in lossesarijd fdoes not'\fcompletely"remove the break. "Thefbreak is'apoison for leadcatalysts ernpioyed in` formation fof alkydw-resins. V'The'preseritiirnention is basedupon thel "discoverythat Whenjglyceride' foils 'aratreatednrith an alkalsuh'as'odiurn hydroxide'sodium carbonate, sodium bicarbonate or` the corresponding potassium coinp'oundsijgin lorderrpartially" to `decornjpose `such l*break forming constituents as lecithin "or "other phosphatide'sf/ occurring- "in "the natural4 or crude oil,"theyormmproducts `Whicl'l ean""the'n be successfully neutralized with an 'ajc'id j'such as "sulfuric jac'id, hydrochloric acid, phosphoric 'acidpr organic acids suchas` acetic a'crd,-rnaleic acidor the-dike 4tolprovide ai'break lfr'eeoil.

i The' behavior of' the #break Aconstituents man b e explained 'up'onirthe"theory"'that phosphatides such as" lecithin "spliteither-betweentheglycjerol nucleus `and the Aphosphori'cacid'radicalfortbetween i the A'latter' raplifoalfand' thebasic group; e. gchoflinej orjtljianolarnine. t Vrn'ay he" 'that the split iny jsoine'instanc'es will ib'e n atj'one @position and 'in'` otherfiiistanceshit Willfbe' k.at'fth'ej'othenso thaihere vorbeiamanreofetheztwotypes/of Products'ihttho ^foilfsbsoquontlynt ve noilrcan bofdriodl to. eliminato-Water. andto. precipitato tho the alkali and perhaps choline and the acid may be washed out by treating the oil with water and nally drying the oil by blowing it with inert gas, e. g. CO2.

The salts, if filtered out, may further be washed with a solvent such as naphtha designed to extract out the glycerides which may be absorbed in or cling to the salts. By such treatment, practically all of the oil is recovered. The recovered portion may be returned to the oil or may be added to the next batch as desired. The usual separation of degraded products from the main body of the oil is thus avoided and rening losses are cut to a minimum.

In the practice of the invention, an oil containing gum or break constituents, such as a whole soybean oil, corn oil, linseed oil or cottonseed oil, or a raffinate oil obtained by furfural extraction of a glyceride oil as described in U. S. Patent 2,200,391, is treated with alkaline material preferably in the form of a water solution. The amount should be comparatively low, and may, for example, be within a range of from .01 to 1.00% solid alkali added as a solution per pound of oil.

The mixture of oil and alkali solution preferably, are agitated together for sufficient time to permit adequate reaction of the constituents therein. This reaction may be promoted by heating the mixture moderately during the ag1tation, for example, to a temperature of 50 to 100 .0. Agitation may be continued as long as desired but, of course, there is no point in continuing it excessively long, since such operation merely ties up the apparatus, occupies the time of the operator and is power consuming. Usually, a period of twenty minutes to one hour is sufficient.

After the mixture has been sufficiently agitated to obtain adequate reaction between the alkaline material and the break constituents of the oil, acids should be added to neutralize the alkali. For this purpose, phosphoric acid, sulfuric acid, hydrochloric acid or organic acids such as acetic, maleic or fumaric or other acid capable of decomposing fatty acid soaps may be employed.

The amount should be sumcient, or slightly in excess of the amount required approximately to neutralize any free alkali and to decompose the alkali salts in the solution. The correct amount, of course, can easily be calculated from the amount of alkali added or, if preferred, by titration of samples of the oil from time to time as acid is added.

As previously stated, removal of the alkali salt can be effected either by drying the oil and thus precipitating the salts so that they can be ltered out, or by washing the oil with water in order to extract out the salts. The oil should be dried after acidification or after washing with water, for example, by bubbling inert gas such as carbon dioxide or nitrogen therethrough at an appropriate temperature, e. g. 100 to 200 C. Lower temperatures can be employed but the removal of the water is then slower. Also vacuum could be applied to hasten the drying operation at a moderate temperature.

After the salts have been removed, the oil product as obtained, is only slightly higher in acid value than the original oil. Doubtless, it contains nearly all of the fatty acids and glycerides with which it started so that rening losses are no more than a few tenths of a percent, yet it is perfectly satisfactory for most uses to which the oils are conventionally applied, e. g. as modifiers of, or raw materials for alkyd resins for use in 2,510,379 f -Y A coating compositions. 1n the latter, it does not poison the catalyst. The oil may also be subjected to further treatment as, vfor example, solvent fractionation as above described. If treatment with alkali then with acid, without further treatment is employed, the coloring of the oil will be about the same as that of the original oil. If lighter products are desired, the break free product as obtained by the application of the foregoing technique, is excellently adapted for simple bleaching operations. For example, the treated oil can be admixed with l to 5% of fullers earth or acid activated bleaching clay, e. g. acid treated bentonite, or with activated charcoal such as bone char or other bleaching `agents and the decolorizing agents filtered out to obtain oil of very light color. The bleaching agent, of course, will carry out a certain amount of oil absorbed or adherent thereto. This oil can easily be recovered by extraction with naphtha and, evaporation of the naphtha therefrom. The oil recovered from the bleaching agent in this manner is notl of excessively dark color and can be added to the next batch or the parent batch if desired.

The following examples are illustrative of specific applications of the principles of the invention.

Example 1 One hundred parts of partially degummed soybean oil (-24% free fatty acids, 10.5 Gardner color, 133.5 I. V.) Was treated with 1.7 parts of 8% sodium hydroxide solution at 25 C. for 30 minutes and at 65 C. for 30 minutes. Enough phosphoric acid (0.136 part) was added to neutralize the alkali used and the mixture heated to 110 C. and dried by bubbling inert gas. Two parts of an acid activated bleaching earth was added and agitation continued for 30 minutes. The filtered oil had a free fatty acid content of 0.36, a negative Gardner break test, and a Gardner color of 4. The oil readily underwent an alcoholysis with glycerol with litharge as a catalyst, indicating that the break had been transformed to an innocuous form. The oil loss including that on the spent clay was 1.50%, but if the oil on the clay were recovered with naphtha. the loss was only 0.177%.

Example 2 One hundred parts of crude linseed oil (0.88% free fatty acids, l1 Gardner color, 177.0 I. V.) and giving a positive break test, was stirred with 5.9 parts of 8% alkali for 30 minutes, then heated to 65 C. A 15% solution of sulfuric acid, 5.46 parts, was added and the mixture stirred and heated to 110 C. Four parts of bleaching earth was added and the temperature allowed to fall to C. `where it was held until 30 minutes from the addition of earth had elapsed. The oil was then ltered to yield a product having a fatty acid content of 1.90%, a negative Gardner break test, and a Gardner color 'of 4. The loss after the spent earth had been freed of oil by a naphtha wash was 0.31%. The oil recovered from the spent cake with naphtha contained no break and was not excessively dark and could be Iadded to the next batch or the main body of oil if desired. The product underwent `an alcoholysis with glycerol in the presence of litharge with no poisoning effects.

Example 3 One hundred parts of crude soybean oil (0.38%

free fatty acids, 10.5 Gardner color, 135.0 I. V.) and giving a positive break test was treated with i75l7r-1212l15 0f 8% alkali solutionf for 30 -min-utesrlai. room temperature and heated to 65 C. Then k12-parts of r15-.% sulfuric-.acid solution was added mld-inertgas (CO2) was bubbled into the mixtureia-nd the temperature raised to 110 C. Two ,parts-by 'weight of an acid activated bleaching earth lwas `.added and agitation continued for 30 minutes. The mixture was iilteredand a breakfree oilfwith 1.90% free fatty acids, la Gardner .color-fof 4.5 resulted. A loss of 0.28%` resulted if the iiltercakewas washed free ofoil with naph- .tha. The oil washed from the cake-was of good color and break-free. The product reacted .prop- .erly :.withvglycerol in the 4presence of litharge showing that the catalyst poisons had been eliminated or rendered innocuous.

Example 4 One hundred parts of crude soybean oil (0.63% Ifree'fa-ttyacids, l13rGardner-color, 131.9 iodine va-lue) 'andz giving'a positive break that was treated with 8.4 parts of 8% alkali solution at 65 1C.for 30 minutes and then acidied with 10.32 parts of 15% sulfuric acid. The temperature was raised to 110 C. and held there until .the mixture was dry. The oil was allowed to cool and the inorganic salts filtered. The loss of material remaining on the cake was 1.51% of the oil after entrained oil was removed as a naphtha wash. As bleaching earth was not used, the color gof -oil was only .sl1ghtly improved, -but it was( break-free and underwent an alcoholysis readily. The final. free fattyvacid content was 3.20%.

Example One hundred parts of solvent extracted partially degummed soybean oil (0.30% free fatty acids, 10 Gardner color, 136.8 I. V. and a positive Gardner break test) was treated with 1.8 parts of 8% alkali for 30 minutes at room temperature. The temperature was raised to 65 C. and 1.66 parts of sulfuric acid solution was added. The mixture was dried by heating to 110 C. and filtered. The resultant oil was break-free and had a free fatty acid content of 0.55%, but as no bleaching earth was used was the same color as the original oil.

Eample 6 A sample of crude cottonseed oil (I. V. 110.2, F. F. A. 1.03%, 13 Gardner color, and a positive Gardner break test) was treated with 8.3% by Weight of a 12 B. caustic soda solution. The mixture was stirred at 25 C. for 30 minutes and then heated to 65 C. and stirred for 30minutes. 'Inhe mixture was then acidiiied with 7.66% of 15% sulfuric acid solution and allowed to settle.

The lower aqueous layer was withdrawn and the ExampleI 7 One hundred parts of a crude hydraulic pressed linseed oil (1.05% F. F. A., a positive Gardner break test, and 10 Gardner color) was treated @wiwi-,6.2 parts ef 8%ralka-li solution at.' 25 .G1-,fof 30 minutes. The mixture was heated .to 1652.36. and 5.1711 parts-of- 15.%sulfuric acid was ,added .with stirring. The Ymixture was then dried'by .heating to C. and three parts of an acid-.acftivated bleaching earth was added and steamV introduced. The mixture was stirred 30 minutes .with steam `and 15 minutes to dry the mixture and then filtered. The gross oil loss was 2.27%, but if theoil on the earth were recovered, the net losswas only 0.31%. The oil recovered from the earth could .be added to the major fraction ortothevnext batch. The final 'oilhad a Gardner'colorzof v6, a free fatty acid content of 1.875%, and a negative break test.

Example 8 One hundred parts of crudeexpeller. ylinseed oil-1 Was treated with 5.8 parts of 8% alkali, ,5.36 parts of 15% sulfuric acid, and .three parts of bleaching earth as described above in Example 7. The original oil had a Gardner color :.of 12,-a F. F. A. content of 0.80% and a positives-break test. The nal oil has a Gardner color of ,5, 1.49% F.v F. A., and a negative break test. The loss',y ifmechanically held oilon the Yspent earth was :removed .with naphtha, was 0.48%.

The .steps of decolorizing the oil is not yrequired where Vtheoil .isinherently of light color or ifa lightl colored `product is .not demanded. Any surface :active adsorbentmay be employed in decolorizing. Acid activated clays such asareemployednin the mineral'oil and other industries, fullers earth and the .likeare examples.

Theioils of the examples could be admixedwith drliers,ve. g. .1 to l5% lead cobalt or manganese oleates or naphthenates to make paints and varnishes. They could be fractionated by the technique of Freeman Patent 2,200,391 to obtain high iodine value and low iodine fractions. They could be cooked with phthalic acid and glycerinek in place of conventionally alkali rened oils to provide alkyds of any desired oil length and were not poisonous to the catalysts.

It is a feature of the invention that the gum and break constituents of the oil are removed or converted by the combination of steps to an innocuous form in which they will not separate when the oil is heated to break temperature and they Will not poison such catalysts as litharge. The advantages of alkali refining are thus secured with little or no loss of valuable oil as foots or soapstock.

The forms of the invention herein shown and described are to be regarded merely as exemplary, and it will be apparent to those skilled in the art, that numerous modifications may be made therein, without departure from the spirit of the invention or the scope of the appended claims.

I claim:

1. A method of treating oil containing break constituents for purposes of overcoming a tendency to produce break, which process comprises treating the oil with an alkali, then further treating the oil with a strong acid in an amount approximately equivalent to the total alkali with which the oil was treated and subsequently removing the resultant salt of the alkali and the acid.

2. In a process of treating a glyceride oil containing break constituents, the steps which comprise treating the oil, rst with a small amount of caustic soda in solution in water, then with a strong acid equivalent in amount to the total caustic soda introduced, drying the oil and lter- :lng off the saltsv of the caustic soda andthe strong acid.

3. In a process of treating a glyceride oil containing break constituents, the steps which comprise treating the oil with a small amount of an alkali adapted to react with the break constituents of the oil, then subsequently adding a strong acid in an amount equivalent to the total alkali added and removing the resultant salts of the alkali and the acid, and drying the oil.

4. A process as dened in claim 3 in which the amount of alkali is in excess of .01%.

5. A process as defined in claim 4 in which the v-oil after addition of the acid is treated With an adsorbent as a bleaching agent.

6. The steps as defined in claim 3, in which the removal of the salts is eiected by water- Washing the oil.

7. The steps as defined in claim 6, in which the oil treated is linseed oil.

8. A method of forming a break negative oil from oil containing break constituents, which process comprises adding to the oil approximately .0l to 1% of alkali as a Water solution, then adding a strong mineral acid in an amount equivalent to the alkali added and removing the salts of the mineral acid and the alkali from the oil.

9. A method of treating soya bean oil containing break constituents for purposes of overcoming the tendency of the oil to produce break when heated, which method comprises adding to the oil .01 to 1% of caustic soda as a water solution, agitating the mixture to effect thorough contact between the oil and the caustic soda, then adding a strong mineral acid in an amount equivalent to all of the caustic soda added, and removing the 8 resultant salts of the strong mineral acid and sodium.

10. A method of treating soya bean oil containing break constituents for purposes of overcoming the tendency to produce break when the oil is heated, which method comprises agitating the oil with .0l to 1% of caustic soda at a temperature of to 100 C. until the oil is thoroughly contacted with the caustic soda, then adding a strong mineral acid in an amount equivalent to all of the caustic soda added, drying the oil and removing the salts of sodium and the strong mineral acid therefrom.

11. A process as defined in claim 10 in which the oil is subsequently bleached by contacting it With an adsorbent clay.

12. A process as dened in claim 10 in which the oil is subsequently bleached by contacting it with an acid activated clay.

13. A process as defined in claim 10 in which the oil is subsequently bleached by contacting it with fullers earth.

ROGER. M. CHRISTENSON.

REFERENCES @FEED The following references are of record in the le of this patent:

UNTED STATES PATENTS Jakobsen Aug. 31, 1948 OTHER REFERENCES Bailey: Oil & Fat Products (1945), Interscience Pub. Inc.. page 507.

Claims (1)

1. A METHOD OF TREATING OIL CONTAINING BREAK CONSTITUENTS FOR PURPOSES OF OVERCOMING A TENDENCY TO PRODUCE BREAK, WHICH PROCESS COMPRISES TREATING THE OIL WITH AN ALKALI, THEN FURTHER TREATING THE OIL WITH A STRONG ACID IN AN AMOUNT APPROXIMATELY EQUIVALENT TO THE TOTAL ALKALI WITH WHICH THE OIL WAS TREATED AND SUBSEQUENTLY REMOVING THE RESULTANT SALT OF THE ALKALI AND THE ACID.