US2982692A - Dewaxing of oils - Google Patents

Description

- any wax-containing oil, including both vegetable oils liquid fractiomhoiling rangeunder 20",, c onsists mainly' of buta'ne and pentane. i The next fraction, petroleuni ener t n oi such as dies th'ebasis of volatility; yiscosit Forsqme ypeset petrole fur er distillaticnuml sweated or f shalloyy Fatented May 2, 1961 ice benzine or other solvents and chilled, permitting a further separation of oil from paraffin. The latter is then filtered hot, through charcoal and cast into blocks, re-

2,982,692 sulting in, the familiar crystalline parafiin utilized for paper coating, candles and pharmaceutical ointment bases.v

The oil filtrate from paraflin presses is steam distilled,

and the residual oil purified by filtration through bleaching clays, yielding high grade lubricating stock oils and heavy mineral oil. (Textbook of Organic Medicinal and 0 Pharmaceutical, Chemistry-Wilson and Gisvold; 3rd'ed.,

19.56,. I. B. Lippincott, PP- 60, 61.)

' Vegetable oils and waxes Fats and oils are found widelydistributed in nature, This invention relates to processes for dewaxing oils in bgth the plant and animal kingdoms. Waxes likeand refers more particularly to a process for dewaxing wiseare naturalproducts but .difier slightly from the fats and oils in their basic composition. Whereas the fats and oils are mixtures of the glycerides of various, fatty I acids, the waxes are mixed esters of higher polyhydric alcohols other than glycerol with fatty acids. Petroleum is the ma or source of hydrocarbons. v The 7 various natural Oils. 'difi in regard to their fatty composition of crude petroleum is very complex. It 1 s vaciigame-11;: Thgsg agids fall within 1 the Saturated made up of hundreds of dlfiterent compounds. 'In addlries, asexe p fi d by stea q id 3 141 are the basis tion to small percentages of nitrogen, sulphur and oxy f lthe: nqmhying n a 2) mono l Series with" gen-bearing compounds present in, some petrolepms,;the dqubl'enbond betwefiniicarbpns as illustrated by oleic hydrocarbon content may include parafiins, straight and 5 1 and m (3) l lfmi' Series with more than on? I branched-chain types; traces of olefins and other unh doublebond ascsemp fiedhy linoleic a d o enic. saturated aliphatic hydrocarbons; naphthenes or cycloacids) The latter w Glasses f' id being unsammted paraflins of the generic formula C H hav ng five or fumiih the sqmidtying and drying qils, according t thg six carbon atoms in the ring, with parafiiruc or naphthetl c amounts f unsatumfiqn prespmy h Chief rconstitugmsi side chains and aromatic 'or benzene hydrocarbons of t the vegetable 1 1 a the 16 andfl8 c apbQn i genenc fmnula Higher mlicular 9*- Coconut oil is u ique in, that it consists o es e o ch. drocarbons include cycloparafiin-aromatic structures with Short .cflrbqn chain acids, 2 and 1 4 carbcgn acids paraffinic side chains. The composition varies with the, baing presentpin greatest m source Pennsylvania oils have a high content ofparaf- 85 Thejactbr V-detemnining whether Qf thesfi com fi i hydrocal'bmls h. r P raifi s pounds is, termed a fat or an oil is merely its melting M -C n Oils have s r naphthenic l ll?" point. 'The, degree 0t unsaturation of the acids involved: 7 matic hydrocarbon n st n s i 353 51 .95? effectsthe melting point of the-ester mixture, thefmorey P Y i I 4 unsaturatedacids giving e'stersvyith lower melting points; T commel'clal e w of Y bQ fractions these. being the chief constituents, of, the oilsl g si t of a series o distillations crude Pe o eum .The're aret wo-b-road classifications for oilsi edibleiand. and subsequent washings and purificatiqnfir ..The lowest inedible The various edible..oi ls, cottonseed,{olive, ,soybean, corn, etc, are'ernployed for salad dressingS,.other tableuses, andiorcooking purposes- Thehydro'genated fats forcqoking and baking, such asCrisco and .Spry may include'aj widevariety-of vegetablecils, such aslcote tonseed, peanut, and soybean, sincefthefhydr'ogenating processv removesthe color, flavor and odo 'r of the original DEWAXING 0F oILs j HardinB. McDill, P.O. Box 654, Houston, Tex. No Drawing. Filed June 26, 1957, Ser. No. 668,041 4 Claims; c1. 195-3 and mineral oils, by the use of enzymes or yeast.

Petroleum waxes I he boilipg jge 0. s c iefly [p'entane' a d hexane. ia q nsi e a t erteusireldemand may. be,

pl lsqte o r a b in r n 0 9215. ease,

line embraces QQ WidQ range of hydrocarbons 'saturated. Source 7 1 y I anduns tur ted, branch d and stra ht; chain. up; to

I la zsv. f.

Ker sene sf h hydrocarb a ras ie 'cqlle at fwm 175. 9 2 5 d mp is rz Hzs IQ-61611154:

pounds. Gas oil, collectedabove. 275, includes, light -'Thetwo general methods conventionally. employed in ohtaininggvegetable,tats andioils; are expression and sol-' vent, extraction. fottdnseed oil is-us editor shortenings, margarine and .dalad or cookingfoils. Corn oil, is used almost-exclusively as a Saladioili Only coconut oil of I low free'fatty acid content is employed tonedible pure, Bean'ut oil is hydrogenated andrefi'ned foruse ture or margarine, salad and cooking oils e -vegetable shorteningsr The finest; gradeofss' ve urn 213 393 Soybea ius ho ld, bu n ng i eavier furnaee' p s' g nq: r ger.

istics.

steam' sup 'r heating yields thehaWQdistillalte, from which ane's; lubricating:oils andsome light Y in naturalgl y occur-.

a rena-nan dis illat on, s..-.u.t i ed as,

yielding fvga'qr' distillate wig itli g but a similar .wax m ay' be' ob Qlfhe Chemical Process Ind l 1 W. ll press deflecting par arat-ion of: oil and wax. The

Ozocerite is composed of ester waxes, such as montan wax, straight chain hydrocarbon waxes such as paraffin wax and branched chain hydrocarbon waxes. Montan wax (C H O comprises esters of montanic acid.

' w 7 Dewaxing oils V N The dewaxing of oils is a critical problem both in the fields of vegetable oils and mineral oils. In the purifying or refining of vegetable oils, and especially edible vegetable oils, the extraction of waxes from, the individual oils has not developed ,as successfully as has this process in the mineral oil field and several oils have not. been fully exploited as to their commercial uses becauseof this problem. Many of these waxes are very ten'aci-. ous in their adherence to their oil bases or carriers and resist even successive attempts to extract the wax. Rice oil,-for example,-;is onewhich contains a relatively large percentageof wax which is extremely difiicult to remove andthus has not yet been completelyevaluated as to its. potential uses because of this fact, commercially. The methods ofchilling and settling and solvent extraction have been attempted in removing or attempting to remove waxes-fromvegetable oils. These have met with varying degrees of success, as previously noted.

As to the mineraloils, in the refiningof petroleum, it is well known that crudes from certain geographical regions have more or less wax therein. 'Various processes have been developed to dothis, including chilling, settling and centrifuging and solvent extraction employing various solvents. While'it must be "admitted that, largely/the removal of waxes from petroleum andmin- I eral oils is presentlysuccessfully accomplished, such removal is' achieved at-great expense and requires much time, as well as expenditure of energy.

The main objectionto the presence of wax in petroleum products is its relatively high congealing temperature which'interferes with the free, circulation of oil inthe engine. After circulation is established,,the engine performance depends upon the true viscosity of the oil and, not the pour point. At temperatures of complete miscibility, the presence of wax inthe oil may even be beneficial. Dissolved wax improves the viscosity index, lowers the carbon forming tendenciesand has a minor effect on the other oil properties. Nevertheless, due to the temperature difficulties, in the majority of petroleum products, the presence of wax is regarded'as a severe disadvantage and problem.

Therefore, an'.object of theinvention is to provide a process of dewaxing oils which will swiftly, easily. and cheaply remove waxes'from wax-containing oils;

Another object of theinvention is to provide such a 7 process which will dewaxoils of either vegetable or mineral source, including the ediblevegetable oils petroleum oilsl I p I Another object .of theinvention is to provide'a methodi of dewaxing wax-containing. oils of either. vegetable or mineral origin by the additionof relatively .small quantiand the 'ties of easily obtainable chemical substances .and bio chemical substancesvthereto; p I

Another object v ofthe invention is to'provide' such' a; process for dewaxing wax-containing, oils wherein there is no problem of separating thev dewaxingcliemical sub origin which will substantially and completely remove waxes from these oils whereby to obtain color and clarity inthe dewaxed oils at least equal to the best dewaxing processes now existent and in most cases far superior thereto.

Another object of the invention is to provide a process for dewaxing wax-containing oils of either vegetable or mineral origin which will remove waxes from oils which have previously not been successfully dewaxed either experimentally or commercially. 7

Still another object of the invention is to provide a treatment process for crude mineral oils and petroleum with yeast wherein not only is the crude dewaxed but at least a partial separation of the hydrocarbon fractions is achieved without the application of heat to the crude or the use of expensive distillation equipment.

Other and further objects of the invention will appear in-the course of. the following description thereof.v

I have discovered that waxes can be removed from. oils, by fermentation treatment employing yeast and/or, enzymes. The waxes removed .include the paratfinic. waxes from petroleum distillates or crudes and, as well,

' the mixed esters of higher polyhydric alcohols with fatty acids which make up the waxes from vegetable oils, and particularly, edible vegetable oils. 3A specific example of the dewaxing process applied on a laboratory scale operation utilizing an edible vegetable oil is as follows:

t (1) /6 oz. of yeast is dissolved in 50 cc. of water and sweetened with a little sugar to assist the fermentation action (2 oz.) which takesplace in the succeeding steps. (2) The foregoing cc. solution is added to 5 gallonsof crude rice oil.

(3) The foregoing mixture is agitated vigorously for several ;minutes at room temperature (approximately 80 F.).

(4) 6 drops of pepsin are added and agitation is continued for several minutes.

. (5) Agitation is discontinued. The mixture is allowed to stand for a period varying from a minimum of 24 hours to a maximum of approximately six days during which continued fermentation causes almost all of the:

wax to settle out.

I (6) The b'ulk'of the wax-free oil can be decanted from,

the vessel and the balance islseparated from the wax.

and yeaSLresidue by centrifuging; thev oil obtained by centrifuging can be added to that which was decantedf (7) The oil ,thusrecovered is essentially wax-free but,

as a precautionary measure, it may be retreated in the samemanner; as the original crude oil, beginning with the addition of the sweetened yeast solutionand pepsim: followed 1 by agitation, settling and; finally, separation of any additional residue from the supernatant oil. The process as'ap'plied to mineral'oils, either'crude or distillate fractions, is exactly thesame as previously de-- scribed as regards the order ofsteps'and the yeast, sugar-- and,pep'sin. lhe results. will 'be exactly the same, al-

* thoughthe time intervals may be slightly different. Therefore, I will 'nqtre'peat the indiv'idualsteps just recited, butv incorporate them with thedifierencesnoted in this para-1.

'. graph to provide specific, examples of the application stances from the treated oils after the dewaxing; p'rocessf I Still another object of the 1 invention is; to" provide a process for dewaxing wax-containing oils of feither vegetable or mineral ,originfwherein-the addition of cer-f tain byproducts of enzymatic activities tolt he oil to be, dewaxed effectively r moves a large proportion of the; wax in the oil'in theifir'st' .stage iof the processa'nd where-" in the'oil, after the first separation maybe retreated by" :--Yet "another ob ect o'f' t myention'is *to: provide; a?

' process for dewaxing oils of'ither 'vegetable (Jr-mineral 7 the same 'pro'cessto remove yetf fur'ther oil so that-the f of the method to mineral oils.

'{I fhav'e discovered .that the critical factor in Z the pepsin addition is "theenzyme peptase for pepsi'nl'm pepsin, the. enzyme, is remarkable in having an 'isoelectric point which is atleast'as far acid as pH The optimum arr; for the 'enzymeis.also irrthejstrongly acid region, being '3 l. 5 to 2.5 Elixir of pepsin is; composed of, the followingi;v

Pepsin g ams"; 35f, Citric acid do 12* Sodiumphosphat, do 7 1s. Distilled water i m 300 Gree q -i And additional-distilled wateflb 1,000=cc."*f a My process 'will dewax oil fromthe following vegetable seeds, nuts and the like: cottonseed, peanut, corn ing: rice bran contains to 18 percent 'rice polishings, 20 percent of oil. The yield of wax recovered, if fecovered from the crude rice oil, is somewhat less than 2 percent or less than .04 of one percent on a bran basis; The oil may be at least partially dewaxed before refining with acid and alkali by the use of a De Laval separator or basket centrifuge. The oil can also be at least partially dewaxed by theme of evacuated unglazed porcelain cylinders coveredwith filter cloth. A good yield is obtained at 20-25'' centigrade with suction at 50 mm; mercury pressure. These studies of rice bran wax were made on the tank settlings from crude rice bran oil. (Cousins, E. R., et al., Journal of American Oil Chemical Society, vol. 30, 9-14, 1953.) C

Other art'states that the crude wax-containing glycerides may be separated from crude rice oil by wintering at 20-25 C; and then treated'with a solvent such as. 5 percent methanol in commercial N-hexane to effect a sharp separation of soluble and insoluble parts. Without the use of the solvent, the wax from the tank'settlings cannot be eifectively separated by filtration methods. Studies have been made of the use of acetone and isopropanol as extracting solvents for tank settlings. It should be pointed out, however, that, despite these statements in the art, there is no commercial method to satisfactorily extract rice oil Wax from the rice oil and yet leave a clear, properly colored oil which will not cloud on reduction of temperature due tothe presence of yet additional Wax therein.

The chemical composition of rice bran wax comprises esters of waxy acids of 22, 24 and 26, carbons combined with alcohols of 26, 28- and-30 carbons. It also contains small amounts of Wax acids of 2.8, 30 and 32 carbons. The softer constituents contain both saturated and unsaturated acids of the range C'14 to C-20. The wax also contains sterols.

The crude rice wax may be at least partially purified by washing repeatedly with methyl alcohol, ether, and, finally, chloroform. This process yields a substance which is an ester mainly composed of tetracosanoic acid and myricyl alcohol (C H OH) with small amounts of saturated acids and some unsaturated acids.

Rice Wax analysis characteristics: percentage of free fatty acids 2.1-7.3, average 3.8; iodine number 11.1-19.4, average 15.2; percentage of unsaponifiable 55.6-67.0, average 58.1; saponification number 56.9-104.4, average I 80.7; percentage 'of phosphorus .01-.18, average .09;

percentage volatile matter .38-2.94, average .94; melting point (drop) degrees centigrade 75.3-79.9, average 77.9;

average made to improve them by removing the-undesirable fatty constituents inherent in crude Wax.

The biological generic term for yeast is Saccharomyces cerevisiae. h

My present concept of the nature of my process is L that thejenzymes in the yeast and the fermentation products may satisfy some of the unsaturated bonds of the The known art on dewaxing rice oil reveals the followcarbon bond in the lubricating .oil wax, Such a reaction may 'c'hangethe crystalline structure of thecomponents of the wax and inthe' higher molecular weight compounds, the crystals may become denser and heavier. This theory is not intended to be limiting.

Yeast enzymes (a partial list) ('1) Di-astase-conversion of starch to sugar;

(2) Cytase-conversion of cellulose to sugar;

(3) Invertaseconversion of polysaccharides to monosaccharides;

(4) Maltaseconversion of maltose to dextrose;

, (5) Milibiase-conversion of 'milibiose to dextrose;

(6) Lactase-conversion of lactose to dextrose;

(7) Zymase contains four elements-alcoholase, oxidase, endotriptase and peptase, these are analyzed below.

(7a) Oxidase-enzymes of this class are considered to be active in the oxidation changes induced in a number of organic substances, such as sugars, aldehydes, alcohols and fats. The oxidase (oxidase) secreted by acetic acid bacteria is Well known for its energetic oxidation of alcohol to acetic acid in the manufacture of vinegar. Yeast oxidase is assumed to .take an active part in building plasma and autofermentation. Its presence is indicated by the heat generated when air is passed through finely divided yeast.

(7b,) Endotriptase-the proteolytic endo-enzyme of yeast is able-to hydrolyze the protein molecule to amino acids and basic substances. It'is considered to be active in the digestion of protein food, the formation of plasma and in regulating the protein content of the cell. Endotriptase is precipitated from yeast juice .with alcohol but cannot be separated from invertase. It ismost active at 45 C- i-n .2% solution of hydrochloric acid and is destroyed at 50 C. Endotript-ase plays an importantpart inautofermentation of yeast.

(7c)v Peptase-this enzyme acts upon the proteins of malted grain, changing them by hydrolysis intopeptones and polypeptides. Its action is promoted in the mash by. the presence of a small amount of lactic-acid. Peptase may be extracted from green malt and is most active at temperatures ranging from 38 C. to 54- C. It is destroyed at 68 C. Y I

The following conditions must be met for the process to be effective. In the first place, the yeast must be living. In the second place, carbohydrate which the yeast will accept as food must be added to maintain the fer- 1 mentation action. Thirdly, the additional peptase or pepsin rnust be added. The live yeast and excess peptase must be agitated in the oil. Finally, a certain amount of settling time must pass. When these conditions are satisfied, the process which I have disclosed will effectively and completely dewax oils of the various kinds set forth previously in one or more treatments.

The best test for determining the presenceof wax in vegetable ormineral oils. after dewaxing processes is,

either freezingthe oils'or subjecting thecils-to successively varying temperatures ranging from very cold to or cloud under conditions of severalyvaried temperatures.

"least six such layers.

(1) The bottom layer, is a yellowish one made of what appears to be the yeast fillers and carriers'which are lower alcohols in therice wax' and the unsaturated hydrogenerally starches of various types. j I

(2) Immediately above the preceding layer I find a blackish, dark layer which very probably are impurities of various sorts together with, probably, asphalts and the like. a a V t (3) Above the preceding layer is what appears to be a kerosene-gasoline layer which is generally about 25 to 30 percent of the total volume of the treated settled crude petroleum and which has a grayish color after the practice of my method.

(4) Above the foregoing layer is a Whitish layer which I am unable to identify at present.

(5) Above the foregoing layer is a layer of generally brownishwax.

(6) Above the wax layer is a layer which appears to be and which I take to be gums of various sorts somewhat similar in appearance to the wax previously mentioned; 1

(7) At the top of all these layers is found the clear, dewaxed, degummed oil.

These various layers can be decanted off or drawn off by various conventional means. The exact composition and components of these various layers I do not know completely at this date, aside from the above speculations, but it is my belief that my method, as well as providing an efiicient dewaxing process, is applicable as well as a crude oil component separating process or fractionating process which requiresno application of heat or expensive apparatus and equipment. The provision of such a separation in the oils treated is thus one of the main features of my invention.

From the foregoing it will be seen that the invention is one well adapted to attain all of the ends and objects hereinbefore set forth, together with other advantages which are inherent to the method.

It will be understood that certain features and subcombinations are of utility and may be employed with-. out reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

, As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter hereinabove set forth yeast and a carbohydrate the yeast will accept as food thereto cause a physical separation of at least a portion of the wax from the oil.

2. "A processof treating an oil containing at least one wax therein comprising adding living Saccharomyces cerevisiae yeast, peptase in addition to any peptase in theyeast, and a carbohydrate the yeast will accept as food thereto to cause a physical separation of at least a por-' tiori of the wax from the oil, separating the wax produced by the first addition from the oil and adding living Sdcchkzrmyces cerevisiae yeast, peptase in addition to any peptase in the yeast, and a carbohydrate the yeast will accept as food again to the separated oil to cause a physical separation of additional wax from the oil.

3. A process of treating an toil'containing at least one wax therein comprising adding living" Saccharniyces cerevpisiae yeast, peptase in. addition to any peptase in'the yeast, and a carbohydrate the yeast will accept aslan energy source thereto, agitating the oil containing the yeast, peptase and carbohydrate 'to mix them thoroughly therein and cause a physical separation of at least a'portion'of the wax from the oil and removing the wax produced from the oil.

-4. A process as in claim 3 wherein the wax removal process comprises letting the wax produced settle and then decanting theoil therefrom.

References Cited-in the file of this patent v UNITED STATES PATENTS 76,974 Barton Apr. 21, 1868 1,753,641 Beckman Apr. 8, 1930 2,316,621- Renner Apr. 13, 1943 2,742,398 Zobe11' Apr. 17, 1956 V FOREIGN PATENTS V N 7 465,111 Great Britain Apr. 26, 1937

Claims (1)

1. A PROCESS OF TREATING AN OIL CONTAINING AT LEAST ONE WAX THEREIN COMPRISING ADDING LIVING SACCHAROMYCES CEREVISIAE YEAST, PEPTASE IN ADDITION TO ANY PEPTASE IN THE YEAST AND A CARBOHYDRATE THE YEAST WILL ACCEPT AS FOOD THERETO CAUSE A PHYSICAL SEPARATION OF AT LEAST A PORTION OF THE WAX FROM THE OIL.