US2307065A - Process for hydrogenating edible oils - Google Patents

Description

Patented Jan. 5, 1943 UNITED muss rnocess I03 llYglltgflNA'llNG EDIBLE No Drawing.

25Claims.

The present invention relates to the preparation or products from glyceride oils which are susceptible to an improvement in stability against rancidity and color or odor, or both. More particularly, the invention relates to a novel treatment of glyceride oils with hydrogen in the presence of a catalyst to provide an improved product particularly with respect to color, odor, plasticity, and stability.

The crude oils which are made available to the manufacturer of glyceride oil products and which have been prepared in accordance with the usual practice are generally dark in color and contain a substantial amount of undesirable impurities, such as free fatty acids, gums, mucilaginous material, and the like. Moreover, these oils are normally odoriferous and otherwise objectionable, particularly when the object is to use them as edible substances for example, for culinary Purposes.

Heretofore, the crude oil generally has been subjected to a series of refining, decolorizing, hy-' drogenating and deodorizing operations to remove objectionable constituents from the oil and to improve its stability, color, odor and fiavor. The particular procedure followed and the severity of the treatment depends to a large extent upon the type and initial purity of the crude oil as well as the desired characteristics of the final product. I

In general, the initial refining of the oil is accomplished by subjecting the oil to a treatment with caustic alkali, which neutralizes and precipitates the free fatty acids as soaps. At the same time, a substantial proportion of the gums, mucilaginous materials, and coloring matter is coagulated and removed along with the fatty acid soaps.

To provide an oil of particularly good quality. it is not uncommon to subject the oil to a rerefining operation in which the refined oil is again subjected to the action of caustic alkali, generally in a more dilute solution. A further removal of foots, although smaller in 'amount, is thus effected which is highly beneficial in improving the quality of the finished product with respect to color and free fatty acid content. An inherent disadvantage of the rc-reflning operation is a substantial further loss of neutral oil by saponification and entrainment, and therefore the use of the re-refining operation is undesirable from an economical standpoint.

Further, in accordance with the art of preparing glyceride oil products, the refined oil is generally improved in color by a subsequent bleach- April 2, 1941,

mum! Serial No. 386,456 3 -.sorbing coloring matter from the oil.

log treatment with a usual bleaching agent of the carbon or earth type. A bleaching agent, it is believed, effects a decolorizing action by ab- The bleaching agents and the absorbed coloring matter are then removed from the oil by filtration. It has been observed that bleaching agents also absorb a substantial amount of oil, and that factor in addition to the relatively high cost of satisfactory bleaching agents and the difilculty and expense of filtration, adds greatly to the expense involved in manufacturing glyceride oil products.

When a hardened product for use in shortening, for example, is desired, the refined and decolorized oil is hydrogenated by means of h drogen gas in the presence of a metallic catalyst such as nickel and generally at elevated temperatures. Incidental to the hardening of the oil, a further improvementin color generally takes place.

The refined and bleached oil, either hydrogenated or unhardened, may then be deodorized by subjecting the oil to a treatment with steam under reduced pressure conditions.

It is an object of my invention to avoid the multiplicity of processing steps heretofore regarded as essential in the manufacture of good grade products from glyceride oils. In particular, it is possible by the practice of my invention odorization, for example, with steam, provides,

glyceride oil products of unexcelled color, odor, plasticity and stability, as discussed more fully hereinafter.

A particular object of my invention is to provide a method whereby unbleached oils may be bleached and hardened simultaneously, if desired,

to at least the'degree required in the production of good grade glyceride oil products. r

The treatment of a prime cottonseed oil for the manufacture of edible oil products by the" methods described above may be taken as typical and involves the problem-o1 color removal. A representative crude cottonseed oil ranges from dark reddish-brown to almost black in color when expressed from the seed. Upon being refined with alkali, a representative oil exhibits a color of approximately 5.0 red/35.0 yellow. All color values referred to herein are in Lovibond units and have been measured with a'Lovibond tintometer provided with a 5% inch column. A subsequent bleach in accordance with the standard procedure approved by the American Oil Chemists Society using 6% of the offlcial fullers earth and employing a temperature-of 105-120" C. im- .proves the color to 'approximately 2.0 red/20.0 yellow. Upon hydrogenation to shortening consistency, such an oil usually exhibits a color of 1.0 red/10.0 yellow.

A cottonseed oii'which has been re-refined with alkali in addition to being subjected to the treatment outlined above, may sometimes,- when choice oils are used, exhibit after bleaching a color of 1.5 red/15.0 yellow and after hydrogenation, a, color of 0.7 red/7.0 yellow. With respect to edible cottonseed oil, a color reduction below approximately 0.5 red previously has not been believed to be economically or practically possible by the prior methods of the industry even when the highest grade raw 911 is treated.

Hydrogenated cottonseed oil is utilized principally as the major ingredient of shortening products. In this connection, it is to be observed that most commercial shortenings average about 2.0 red/20.0 yellow and seldom are below 1.5 red/15.0 yellow. I

It is known in the art that special methods, such as distillation and heat treatments at high temperatures, will eiTect a high degree of color reduction in oils, but these methods, as a rule,

are 'too severe as well as complex and expensive for general use, especially in the preparation of edible oil products.

Therefore, it is an object of my invention to provide a method for decolorizing glyceride oils to a greater degree than has been possible heretofore without adversely affecting the desirable characteristics of the oil with respect to its use, for example, for edible purposes.

A particular object of my invention is to provide a method for decolorizing cottonseed oil to form an edible product which is characterized by an improved water-white appearance.

Another object of my invention is to effect an commercial practice of deep frying, the fat may improved decolorization of glyceride oils in a manner which permits the control of the hydrogenation of the oil whereby an edible oil product of improved color and odor may be produced in a liquid state or having any desired plasticity characteristics.

The problem of odor reversion in edible oils F., usually encountered when the shortening is used for deep frying. The reversion of soybean oil is characterized by the development of varicos 0 flavors and odors known as a "beany flavor or odor and sometimes described as fishy, which subsequently often become altered be maintained at a temperature of about 385 F. for several days, any loss from the fat body being replaced by additions of further shortening. The objectionable odors and flavors which develop are not only undesirable during trying but also unfavorably afiect the odor and flavor of the food products made therewith.

The readily available supply of soybean oil makes its utilization attractive to the manufacturer. Nevertheless, the use of soybean oil has been greatly limited, particularly in high grade edible products, inasmuch as it has been impossible to avoid the undesirable characteristics of soybean dil, particularly with respect to deep frying, unless the oil is hydrogenated and consequently hardened to such an extent that it can be usedonly in restricted amounts. Even with the use of the most efiective hydrogenation methods of the prior art, it has been found undesirable to prepare a satisfactory shortening capable of meeting the high present-day commercial standards and having more than about 10% of hydrogenated soybean oil.

A particular object of my invention is to provide a method of decolorizing glyceride oils such as soybean oil which imparts stability against reversion and good deep-frying characteristics to the oils.

Another object of my invention is to provide a method of forming a soybean oil product stable against reversion under deep-frying conditions and which is sufliciently plastic to be used in unlimited proportions in shortenings.

It is well known in the chemistry of oils and fats that the glycerol esters of fatty acids which are the principal constituents of glyceride oils and fats tend to become rancid due to the formation of various aldehydes and lower fatty acids ity renders the oil unsuitable for most uses, parwith the production of other undesirable flavors and odors, classified as "oleo and grassy.

One of the main objections'to the use, for example, of hydrogenated soybean oil in shortenticularly where the object is to use the oil for edible purposes. The tendency of the oil to turn rancid as the result of oxidation may be minimized by saturating the unsaturated fatty acid components present in the oils with hydrogen.

The stability of the oil, in general, increases proportionately with the decrease in iodine value of the oil. It is understood, however, that complete saturation characterized by the formation of a hard, brittle solid is undesirable, for example, .when the object is to use the oil for edible purposes. In general, it is customary to hydrogenate the glyceride oil to a degree which .gives a product of lard-like consistency at room temperatures. Inasmuch as the usual. types of glyceride oils are not completelysaturated at this consistency, the oil will be susceptible -to undesirable oxidation and the development of rancidity. 1 v

It is an object ofv myinvention to provide a method of hardening glyceride oils and fats whereby the oils exhibit a greater stability ings is the reversion to a characteristic but uh 1 against oxidation and the development of rancidity as compared with oils hardened to the sameiodine value or consistency in accordance with the prior art practice.

I have found that if an oil is subjected to a treatment with hydrogen in successive stages utilizing respectively a catalytically active metal such as nickel and then a metalic oxide catalyst, as described more particularly hereinafter, unexpected results are forthcoming and the above objects, as well as others, are accomplished.

A particular unexpected result obtained by carrying out the successive stages of the treatment with hydrogen in accordance with my invention, is that a degree of decolorization and hardening may be effected which is substantially greater than the sum of the effects produced by utilizing each catalyst alone under similar conditions of temperature, pressure, amount of catalyst, and time with separate batches of oil. Moreover, I

the initial stage of the treatment with hydropassing a current of electricity through a cell containing a dilute solution of an alkali salt of a weak acid and utilizing a nickel anode. The nickel lrvdroxide so prepared may be reduced by means of pure hydrogen gas and at a tem perature of from 300 C. to 500 C.

The initial stage of hydrogenation utilizing a nickel catalyst may be carried out in accordance have found that this unexpected result may be obtained even with only a very slight amount of hydrogenation during the initial stage of my process utilizing a catalytically active metal catalyst.

In accordance with my invention, it is possible to accomplish more desirable results, for example, a greater decolorization and hardening of the oil, than has been possible heretofore utilizing an oxide catalyst alone under the preferred con ditions of its use, or conversely, to effect the same degree of decolorization and hardening with the advantage of using more favorable conditions of operation such as a reduced temperature, pressure, time or amount of catalyst. The utilization of more favorable operating conditions is important not only from the standpoint of economy of processing and the use of less expensive equip ment, but also because the undesirable formation of unsaponiiiable matter is retarded more effectively as discussed more fully hereinafter.

The present invention, which involves an unexpected acceleration of hardening and decolorization during the secondary stage of my process utilizing a metal oxide catalyst, is not to be confused with the pretreatment of, oils as heretofore used, for example, to prolong the life of a catalyst. An unexpected change apparently takes place in the 011 during the initial or primary stage of hydrogenation utilizing a catalytically active-metal such as nickel which results in an unexpected hardening, decolorization, stabilization and other improved activity of the metal oxide catalyst utilized during the secondary stage.

The catalytically active metal which I prefer to use is nickel, although satisfactory results may be obtained with cobalt, platinum, and palladium. It is intended that my inventionshall include the use of compounds of the above metals which are readily reducible during hydrogenation to form the metallic hydrogenating catalyst.

For convenience, the invention will be described more particularly by reference to the preferred use of active nickel. In general, the conditions of operation effective when active nickel is used will be applicable to the use of the remaining species.

A wide range of nickel containing catalysts may be used satisfactorily during the initial stage of hydrogenation in accordance with my invention. Even a spent nickel catalyst obtained from other hydrogenation processes may be used. If desired, and particularly if there is the additional object of effecting substantial hardening during with my invention in any convenient manner known to the art. If desired, a batch type of operation may be used, although in view of the slight amount of hardening required, it may be preferable to accomplish hydrogenation in a continuous manner. In general, it is desired to employ an elevated temperature, for example, in the range of C. to 200 C. and a pressure slightly above atmospheric, for example, in the neighborhood of 40 pounds per square inch. When utilizing a nickel catalyst in powder form, it is generally sufficient to use relatively small amounts such as, for example, about 0.01% based on the welghtof the oil, although greater amounts may be used if desired. In a continuous process, the oil may be passed continuously over a so-called cage or massive catalyst, such as, for example, a closely wound coil of nickel wire, the surface of which has been made catalytically active.

I have found that only a relatively slight amount of hardening during the initial stage of hydrogenation with a nickel catalyst'is sufficient to obtain the unexpected results described, particularly the acceleration of hardening and decolorization, with the secondary hydrogenation using a metal oxide catalyst. In general, it is preferred to harden the oil during the initial stage of hydrogenation to not more than about 5 iodine values, particularly in view of the practical and commercial aspects of the process. The extent of hardening may be controlled effectively by limiting the time of operation or the amount of catalyst employed, or both.

If desired, additional hardening may be effected during the initial stage of hydrogenation, although care must be taken to avoid the formation of too hard a final product as the result of the additional hardening which takes place during the secondary treatment with an oxide catalyst. In general, it is preferred to obtain a maximum proportion of the hardening of the oil during the secondary stage of hydrogenation. I have found that in addition to the highly effective decolorization of the oil which takes place during such secondary hardening, there is obtained a more stable oil as compared with an oil which has been hardened to the same degree of saturation or plasticity utilizing a nickel catalyst alone. Furthermore, hardening with an oxide catalyst is found to be highly selective under a wide range of temperature and pressure and there is little tendency to form undesirable iso-compounds.

After the initial hydrogenation with a nickel catalyst, the oil, preferably free from nickel, is mixed with oxide catalyst and the secondary hydrogenation is carried out, preferably under elevated temperature and pressure as more fully discussed hereinafter.

The oxide catalysts which may be employed satisfactorily in the secondary stage of hydrogenation in accordance with this invention comprise oxides which, for convenience, may be described as the type X-Y-O, in which X is at least one metal selected from the minor subgroups of groups I and II, and Y is at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification. 0, of course, represents oxygen; that is, the metals are in the form of oxides. The minor subgroups of groups I, II, V and VI of the periodic classification comprise divisions of the main groups as shown, for example, in the periodic chart appearing at page 46 of volume I of Inter-' national Critical Tables." The minor sub-group of group I comprises copper, silver and gold. The.

minor sub-group of group II comprises zinc, cadmium and mercury. The minor sub-group of group V comprises vanadium, columbium, tantalum and protoactinium. The minor sub-group of group VI comprises chromium, molybdenum, tungsten and uranium.

It will be apparent that a great number of combinations or mixtures of combinations of the above designated metals are possible. It is to be expected that the activities of the several species of catalysts will vary over a wide range and, ac- 'cordingly, I have selected those metals from the groups designated above which, in general, exhibit the greatest activity under the preferred conditions of operation. It is to be understood, however, that the scope of the invention is not to be limited to the use of the particular metals so selected.

In general, copper and silver comprise the preferred metals of the group designated by X while chromium, tungsten, vanadium and uranium are preferably selected from the group designated by Y. Typical combinations of the selected metals, by way of example, comprise copper-chromiumoxide, silver-chromium-oxide, copper-tungstenoxide, copper-uranium-oxide and copper-vanadium-oxide.

The proportion of metals indicated by X and Y is not regarded as critical and may be varied over a wide range depending upon the particular metals selected and the conditions of operation under which the same is to be used. In general, a substantially atomic ratio of X and Y is preferred for efiecting desirable results in accordance with my invention.

In general, it is preferred to stabilize the catalyst by the presence of an alkaline earth metal oxide, such as barium oxide or calcium oxide, although this is not essential. Substantially an atomic ratio of X and Y and 1/.10 of a mole of alkaline earth metal has generally been found to be preferable, but the proportions may be varied as desired and depending upon the particular metals selected as well as upon the conditions under which the same is to be used.

The exact form of the metals or the oxygen in the catalyst is diflicult to determine, and it is not intended that the invention shall be limited to any particular chemical or physical combination. It is possible that the catalyst may be a simple mixture of the separate oxides of the two metals present in the catalyst, but it is equally possible that the two metals and the oxygen may be combined to form a distinct and separate chemical compound. It is intended that the scope of the invention shall include the use of two or more metals of the type described in combination with oxygen, regardless of the exact chemical or physical structure of the composition. It is possible that even as to those oxide catalysts which, at the present time, do not appear to have a preferred activity, a modification may be made in their physical form or structure which may make their use desirable.

The methods utilized in preparing the oxide catalyst described above will have, in general, an appreciative effect upon their relative effectiveness and properties. A number of varied methods may be employed; it is possible, for,

example, to prepare a catalyst having the desired composition by simply grinding together a mixture of the selected oxides and subsequently heating the mixture to an elevated temperature. Improved results are obtained by precipitating a mixed salt from a solution of hydrated copper nitrate and calcium. nitrate by the addition thereto of a solution containing ammonium dichromate and ammonium hydroxide. The precipitate is dried, pulverized, and decomposed at an elevated temperature to produce a black oxide mass.

A more active catalyst as well as one more uniform and capable of giving reproducible results, may be made by precipitating mixed carbonate from a solution containing the desired proportion: of chromium nitrate, copper nitrate, and barium nitrate by the addition thereto or a solution containing ammonium carbonate. The precipitate is washed, dried, pulverized and decomposed at approximately 350 C.

The amount of oxide catalyst which may be' used in the secondary treatment with hydrogen in accordance with my invention is preferably approximately 0.2% based on the weight of the oil, although this may be varied within reasonable limits. It has been found that when the amount of catalyst is increased, for example, in excess of substantially 0.5%, there is formed an increased amount of unsaponiflable material. When smaller amounts of catalyst are used, the

time required to effect desirable results is greatly increased and in general, it is preferred to use an amount of at least 0.1%.

To effect decolorization and stabilization to the greatest extent, it is preferred to carry out the secondary treatment of my process in a suitable closed vessel wherein the hydrogen may be maintained under relatively high pressures such as in the neighborhood of at least 1500 lbs. per square inch, but this is not regarded as essential for desirable results. For example, pressures as low as atmospheric may be used if desired. In general, a more effective decolorization and stabilization is accomplished at higher pressures.

It is to be noted also, that the secondary treatment may be carried out in a continuous manner, if desired. For example, the oil may be heated and maintained in contact with hydrogen for a desired period of time in an elongated restricted passageway through which the oil may be passed continuously or semi-continuously with or over a catalyst. The oil may then be continuously filtered, if desired, and treated in any of the conventional ways. For convenience, the process is described in the specific examples as a batch operation, as by so doing simple and easily understood standard equipment may be used.

The temperatures which may be used in carrying out the secondary treatment of my invention will generally range from C. to 250 C. In general, an operating temperature of approximately 200 C. is preferred. As the temperature quired, for example, in the production of edible oil products. At more elevated temperatures, particularly above 200 C. there is a tendency toward the formation of unsaponiilable matter -'such.as ketones, alcohols, hydrocarbons, and the higher acids, which are usually considered undesirable in high grade products, although in certain cases this may not be critical. In general,itis desired nottoexoeedatemperature of 260 0., at which point dtion of glyceride oils to take 91100.

It is generally desirable to avoid unduly P longing the secondary-treatment with oxide catalyst to avoid the formation of undesirable byproducts, a particularly unsaponiflable material.

prior art, the hydrogenation of glyceride. oils using a mixed oxide catalyst would result in the formation of unsaponlflable matter comprising higher ketones, such as palmitone and stearone; alcohols, such as distearyl carbinol; hydrocarbons, such as pentatrioontane; as well as corresponding fatty acids, which are very ob- Jectionable inasmuch as they cannot be removed by ordinary deodorization' processes. Unsaponiflable matter is objectionable, for example, in

' edibile food products, because it is not fat. In.

accordance with accepted standards, a good grade shortening will have less ,thanone percent of unsaponifiable matter.

I have found that the decolorization, hardening and stabilization of glyceride oils may be accomplished utilizing an oxide catalyst and without the formation of undesirable amounts of unsaponlfiable matter by regulating the conditions of operation, particularly temperature, pressure,

amount of catalyst and time, as discussed above. It is a particular advantage of my process utiliz-' ing successively a nickel and an oxide catalyst, that effective hydrogenation may be accomplished under the more desirable conditions of operation. Accordingly, by my process, a decolorized, hardenedand stable glyceride 011 product which is suitable for use as a shortening after filtering, deodorizing, texturizing and like finishing, operations, is obtainable having an amount of unsaponiflable components comparable with that ordinarily present in best grade commercial shortenings and intact, uniform products may be made with less than components.-

A illustrative of the unexpectedresults obtained by treating an oil in successive stag s utilizing respectively a nickel and a metal oxide catalyst such as copper chromium oxide, for example, a representative cottonseed oil was hydrogenated about iodine values during the initial stage of the treatment utilizing anickel catalyst and in the secondary stage of treatment, was subjected to the action of .2% copper-chromiumoxide catalyst for 30 minutes at 200 C. and 2500 lbs. per square inch hydrogen pressure. The final 0.5. to 1% unsaponifiable product was found to be hardened a total of 35 iodine values. Ascompared therewith, a batch of the same oil was treated with copper-chromiumoxide catalyst alone under the same conditions ii of operation employed in the secondary stage of the treatment set forth above. At the end of the hydrogenation period, the oil was hardened l0 iodine values. The flnal'color was 2 yellow/.2 red in each case. It will be noted that the hard- 10 ening effect of a treatment in successive stages using a nickel and then an oxide catalyst, was more than three times that obtained by treating the oil with oxide catalyst alone.

As a flu-ther example of the unexpected re- 18 sults obtained by treating glyceride oils with hydrogen. using successively a nickel and a metal oxide catalyst, a mixture of live diiferent vegetable oils refined with caustic alkali and having a color of 35 yellow/24 red, was hydrogenated to shortening consistency, i e., about 60 to 65 iodine values for the particular mixture. The oil was hydrogenated only 3 iodine values during the initial stage using a nickel catalyst, and the desired consistency was obtained in a period 01-8 min- 25 utes after the beginning of the secondary stage of treatment utilizing an oxide catalyst. As compared therewith, an identical sample of the same oil was hydrogenated to the. same consistency with the same oxide catalyst under the same conditions of operation, and it was found that a period of 36 minutes was required to reach the desired shortening consistency. The color was 1 yellow/.1 red in each case.

The above examples of the desirable results obtained by treating glyceride oils with hydrogen using successively a nickel and an oxide catalyst, refer to operations in which the secondary stage of treatment utilizing an oxide catalyst is carried out under relativelyhigh pressures. I have 40 found, however, that the use of high pressures is not essential and desirable results may be obtained at pressures even as low as atmospheric. The following table of results illustrates the improvelnent which may be obtained by a succes- 4 sive treatment under relatively low hydrogen pressures in accordance with my invention, as

compared with a similar treatment using an oxide catalyst alone. The tests were made on a refined cottonseed oil having a color of 75 yellow/7.5 red.

l Hipres- Oolor di -mg Total Sam- 13-; tr e ii li fit the? utilizing drop Y. B. anoxide catal Lbiai/sq. l Oxide catalyst alone '125 a2 0 0 2 Nickel and oxide catalyst 12:; 10.9 4 4 a Oxide catalyst aloneas 7- 1 4 Nickel and oxidecatalyst- 10.4 v 5 5 In each of the above examples in which a nickel and an oxide catalyst were used successively in accordance with my invention, the amount of hardening during the initial stage of treatment with a nickel catalyst was a reduction of only about 3 to 5 iodine values. It will be noted that at each pressure the successive treatment of my invention resulted in both an acceleration of the rate of hydrogenation and an improvement in decolorization.

The treatment of glyceride oils'with hydrogen 75 in succesive stages utilizing successively a nickel above.

and an oxide catalyst, in accordance with my invention, is particularly effective for a more complete decolorization of oils such as, for example, cottonseed oil, than has been possible heretofore in accordance with the usual practice and this .is accomplished without resort to the uneconomical steps of re-reflning and bleaching with, for example, bleaching earths as discussed In addition, a hardened oil prepared in accordance with my invention is found to be more stable against ordinary oxidation and thedevelopment of rancidity, as compared with a similar oil hardened to the same degree of plasticity or saturation utilizing a nickel catalyst alone. With respect to oils which revert such as, for example, soybean oil which develops a characteristic, although undesirable, odor upon standing and particularly when subjected to the elevated temperatures of deep-frying as discussed above, my process efl'ectively stabilizes such oils against reversion.

I have found that glyceride oils which have been processed in accordance with my invention, in addition to having an improved color and stability against rancidity and reversion under deep-frying conditions, have all of the qualities requisite for conversion to, and use in, an allpurpose shortening. It'ls understood, of course, that the glyceride oils which have been'hydrobleached in accordance with my invention will be finished in the conventional manner such as, for example, by filtering, deodorizing, chilling, aerating and texturizing when the same is to be used in edible products such as shortenings. A shortening made from oils treated in accordance with this invention is plastic and workable over a reasonable range of temperatures, and may be readily creamed and when used for baking purposes, produces cakes of good volumne and texture.

Although the invention has been described particularly with reference to cottonseed oil and soybean oil, it is to be understood that this has been done merely for convenience and to assist those skilled in the art to appreciate the novel and desirable results which may be attained. It will be apparent that my invention is applicable to all glyceride oils and fats or mixtures 'thereof'of animal, vegetable or marine origin, which are susceptible to an improvement in color or stability or both. Among the oils which have been treated successfully with hydrogen in accord-, ance with the invention are', for example, palm oil, sesame oil, peanut oil, coconut oil and tallow.

The variations to which this invention is susceptible by one skilled in the art are intended to be in included within the scope of the fol-' lowing claims.

We claim: l. A process for hydrobleaching glyceride oils to form products having a minimum of unsaponlflable components and an improved color and stability comprising hydrogenating the oil at an elevated temperature in the presence of a nickel catalyst to reduce the unsaturation of the oil not substantially more than 5 iodine values, removing the nickel catalyst from the oil, treating the oil with hydrogen at a temperature ofbetween substantially 130 and 250 C. under a pressure in the neighborhood of 100 atmospheres, for a period of-time not substantially greater than 60 minutes and in the presence of not substantially more than 0.5% of a catalyst having the general formula XYO, in which X represents at least one metal selected from the group consisting of copper and silver, and-Y represents at least one metal'selected from the group consisting of chromium, vanadium, tungsten and uranium.

2. A process for hydrobleaching lyceride oils to form products having a minimum of unsaponiflable components and an improved color and stability comprising hydrogenating the oil in the presence of a nickel catalyst, removing the nickel catalyst, and treating the oil with hydrogen at a temperature of not more than substantially 250 C. in the presence of a catalyst having the general formula X--Y--0 in which Xrepresents at least one metal selected from the minor subgroups of groups I and II, and Y represents at least one metal selected from the minor subgroups of groups V and VI, of the periodic classification. h a

3. A process for hydrobleaching glyceride oils to form products having a minimum of unsaponifiable components and an improved color and stability comprising treatin the oil with hydrogen at an elevated temperature initially in the presenceof a nickel catalyst, and subsequently in the presence of a actalyst having the general formula XYO in which X represents at least one metal selected from the minor sub-groups of groupsI and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification.

4. A process for hydrobleaching glyceride oils to form products having a minimum of unsaponifiable components and an improved color and stability comprising hydrogenating the oil in the presence of a nickel catalyst, removing the nickel catalyst from the oil, and treating the oil with hydrogen at an elevated temperature under a pressure of at least 100 atmospheres in the presence of a catalyst having the general formula XY-0 in which X represents at least one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification.

5. A process for hydrobleaching glyceride oils to form edible products having a minimum of unsaponifiable components and an improved color and stability comprising treating the oil with hydrogen in the presence of a catalytically active metal selected from the group consisting of nickel, cobalt, platinum, and palladium, se'parating the catalytically active metal from the oil, and treating the oil with hydrogen in the presence of a catalyst having the general formula X Y--O in which X represents at least one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification.

6. A process for hydrobleaching glyceride oils to form edible products having a minimum of untemperature of not more than substantially 250 C. initially in the presence of a small amount of A of a small amount of a catalyst having the general formula X-Y-O, in which X represents at least one metal selected from the group consisting of copper and silver, and Y represents at least one metal selected from the group consisting or chromium, vanadium, tungsten and uranium.

8. A method oi hydrobleaching glyceride oils which comprises hydrogenating the oil in the presence oi a nickel catalyst to reduce the unsaturation or the oil not substantially more than 5 iodine values, removing the nickel catalyst from the oil, and subjecting the oil-at a temperature of not more than substantially 250 C. to the action of hydrogen in the presence of a small amount a catalyst having the general formula XY0, in which X represents at least one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI of the periodic classification.

9. A method of hydrobleaching glyceride oils which compriseshydrogenating the oil at an elevated temperature in the'presence of a nickel catalyst to reduce the unsaturation oi the oil not substantially more than iodine values, removing the nickel catalyst from the oil, and subiecting the oil at a temperature of not more than substantially 250' C. to the action of hydrogen in the presence of a small amount of a catalyst having the general formula XY0, in which general formula X-Y-Z-O in which X represents at least one metal selected from the minor sun-groups of groups I and II, and Y represents at. least onemetal selected from the minor subgroups of groups V and VI, of the periodic classiilcation, and Z represents an alkali earth metal.

11. A process for hydrobleaching glyceride oils to form products having a minimum of ungreater than 250 C. in the presence of a small amount of a catalyst comprising copper, chromium and oxygen.

1 3. A process for hydrobleaching glyceride oils to form products having a minimum oi unsaponiliable components and an improved color and stability comprising hydrogenating the oil in the presence of a, nickel catalyst, removing the nickel catalyst from the oil, and treating the oil with hydrogen at a temperature not substantially greater than 250 C. in the presence of a small amount of a catalyst comprising silver, chromium and oxygen.

14. A process for h'ydrobleaching glyceride oils to form products having a minimumof unsaponifiable components and an, improved color and stability comprising hydrogenating the oil in the presence of a nickel catalyst, removing the nickel catalyst from the oil, and treating the oil with lwdrogen at a temperature not greater than substantially 250 C. in the presence of a small amount of a catalyst comprising copper, vanadium and oxygen.

15. A process for hydrobleaching glyceride oils in which X represents at least one metal selected .elevated temperature with hydrogen in the presence of a small amount of a catalyst having the saponiiiable components and an improved color a and stability comprising hvdrogenating the oil inthe presence of a nickel catalyst, removing the nickel catalyst from the oil, ,and treating the .oil at an elevated temperature with hydrogen in the presence of a small amount of a catalyst having the general formula X-Y--ZO, in which X represent: at least one metal selected from the group consisting of copper and silver, and Y represents at least one metal selected from the group consisting of chromium, vanadium, tungsten and uranium, and Z represents an alkali earth metal, said metals represented by x and Y being present in substantially atomic relationship and said metal represented by Z being present in one-tenth molar relationship.

7 12. A process for hydrobleaching glyceride oils to form products having a minimum of unsaponiiiable components and an improved color and stability comprising hydrogenating the oil in the presence of a nickel catalyst, removing the flable components and an improved color andv from the group consisting of copper and silver, and Y represents at least one metal selected irom the group consisting of chromium, vanadium, tungsten and uranium.

16. A method of stabilizing soybean oil against. reversion under the high temperature conditions of deep fat frying, which comprises hydrogenating the oilin the presence of a nickel catalyst, removing the nickel catalyst from the oil, and treating the oil with hydrogen at an elevated temperature inthe presence of a small amount of a catalyst having the general formula XYO, in which X represents at least one metal selected from the minor sub-groups of groups, I and II, and Y represents at least one metal selected from the minor sub-groups of groups V andVI, of the periodic classification.

' 1'1. A process for hydrobleaching glyceride oils to form products having a minimum of unsaponiflable components'and an improved color and stability comprising hydrogenating the oil with hydrogen at a temperature of from to 200 C. in the presence of about 0.01% nickel catalyst, removing the nickel catalyst from the oil, and treating the oil at an elevated temperature with hydrogen in the presence of a small amount 01 a catalyst having the general formula X-YO in which X represents at least one metal selected from the minorsub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification; I

18. A process for hydrobleaching glyceride oils to form products having-a minimum of unsaponistability comprising hydrogenating the oil at an I elevated temperature in the presence of a nickel catalyst for a sufficient period oi-time to reduce the iodine value of the oil, reinoving the nickel catalyst from the oil, and treating the oil with hydrogen at an elevated temperature in the presence of a small amount of a catalyst having Y the general formula XY--O, in' which X represents at least one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor subgroups of groups V and VI, of the periodic classi- -fication.

19. A process for hydrobleaching lyceride oils to form products having a minimum of unsaponiiiabie components and an improved color and stability comprising hydrogenating the oil at an elevated temperature in the presence of a small amount of a powdered nickel catalyst, filtering the catalyst from the oil, and treating the oil at an elevated temperature with hydrogen in the presence of a small amount of a catalyst having the general formula X-YO, in which X represents at least one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups 01 groups V and VI; of the periodic classification.

20. A process for hydrobleaching glyceride oils to form products having a minimum of unsaponiflable components and an improved color and stability comprising continuously hydrogenating the oil in the presence of a nickel catalyst to reduce the unsaturation in the neighborhood of 5 iodine values, and completing the treatment of the oil withhydrogen at an elevated temperature in the presence of a catalyst having the general formula X-Y-'-0 in which X represents at least one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification.

I 21. A process for hydrobleaching glyceride oils to form products having aminimum of unsapon- -ifiable components and an improved color and stability comprising continuously hydrogenating the oil initially in the presence of a nickel catalyst to reduce the unsaturation in the neigh-' borhood of 5 iodine values, and subsequently in the presence of a catalyst having the general formula XYin which X represents at least tionof the oil not substantially more than iodine values and thereafter treating the oil at an elevated temperature with hydrogen in the presence of a catalyst having the general formula at a temperature of not more than substantially 250 C. in the presence of a catalyst having the general formula X-YO in which X represents at least one metal selected from the minor subgroups of groups I and II, and Y represents at least one metal selected from the minor subgroups of groups V and VI, of the periodic classification.

24. A process for hydrobleaching glyceride oils to form products having a minimum of unsaponifiable components and an improved color and stability comprising treating the oil with hydrogen at an elevated temperature initially in the presence of a catalyticallyactive metal selected from the group consisting of nickel, cobalt, platinum,

one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification. 22. A process for hydrobleaching glyceride oils to form products having a minimum of unsapon- -ifiable components and an improved color and stability comprising passing the oil through a massive nickel catalyst to reduce the unsaturaand palladium, and subsequently in the presence of a catalyst having the general formula X--YO in which X represents at least one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification.

-25. A process for hydrobleaching glyceride oils to form products having a minimum of unsaponifiable components and an improved color and stability comprising hydrogenating the oil in the presence of a catalytically active metal selected from the group consisting of nickel, cobalt, platinum, and palladium, removing the catalytically active metal from the oil, and treatingthe oil with hydrogen at an elevated temperature under a pressure of at least atmospheres in the presence of a. catalyst having the general formula X-Y0 in which X represents at least one metal selected from the minor sub-groups of groups I and II, and Y represents at least one metal selected from the minor sub-groups of groups V and VI, of the periodic classification.

- WILLIAM J. PATERSON.