US2671097A - Process of hydrogenating vegetable oil - Google Patents

Description

Patented Mar. 2, 1954 PROCESS OF HYDROGENATING VEGETABLE on.

Harvey D. Royce and Langdon C. Haskell, Savannah, Ga., assignors to The Southern Cotton Oil Company, Savannah, Ga., a corporation of New Jersey No Drawing. Application July 13, 1950,

Serial No. 173,684

8 Claims.

This invention relates to an improved plastic hydrogenated vegetable oil having a combination of superior stability against rancidity, and a soft plastic consistency at normal working temperatures, near 70 F. The product of the present invention also has the advantage of an unusually low melting point for a given stability. Other advantages of the product over conventional hydrogenated oils of similar consistency will be shown later in conjunction with the presentation of specific examples.

It is well known, as outlined in many previous patents on selective hydrogenation and in the literature on hydrogenation, that certain types of selective nickel and nickel-copper catalysts, such as nickel and nickel-copper, under certain hydrogenation conditions, notably hydrogenation temperature, pressure, rate of agitation, hydrogen purity, and catalyst concentration, can be chosen to yield a fairly stable hydrogenated oil at a given iodine value (I. V.). Unfortunately it is also true that some of the hydrogenation conditions, notably temperature, which favor high stability, also favor the development of a hard brittle consistency at 60 to 70 F., in which range it is desirable for many purposes to produce a soft plastic fat.

In other words, most hydrogenation conditions which favor selectivity and consequent high stability, also favor the formation of solid isomers of oleic glycerides, which impart a hard brittle consistency at a temperature in the neighborhood of 65 F. to the product, when the hydrogenation is carried to a sufliciently low iodine value to yield a fat stable against oxidative rancidity, for example, one having an active oxygen method stability of approximately 200 hours. The active oxygen method (A. O. M.), also known as the Swift stability test, is one commonly used in the oil and fat field to test products for resistance to oxidation, and it is fully described by King et. al., in Oil and Soap, volume 10, page 204 (1933). Since it is becoming a genera1practice for large users of hydrogenated vegetable oils, such as margarine manufacturers, biscuit and cracker manufacturers, and producers of potato chips, to specify a minimum limit for A. 0. M. stability, generally 100 to 200 hours, and since they desire a product which is plastic and workable at ordinary temperatures, down to 60 F., it

2 is plastic within a range of 60 to 70 F., and which has an inherent glyceride stability superior to conventional hydrogenated oils of the same degree of plasticity.

In general, this invention consists in the process of hydrogenating vegetable oils with conventional metallic hydrogenation catalysts, such as finely divided nickel, nickel-copper, palladium, or platinum, in the presence of a fat-soluble phosphatic ester, said ester comprising the ethanol soluble reaction product of a partial ester of a polyhydric alcohol with phosphoric anhydride and a primary aliphatic amino alcohol, said reaction product represented in part by the in which P is phosphorus, O is oxygen, R is hydrogen or an alkyl group, OY is an aliphatic primary beta amino alkoxy radical linked to P through its oxygen, X is a 'polyhydric alcohol roup with at least one of its hydroxyl groups esterified with a fatty acid, and n is a small whole number. This class of phosphatic esters is disclosed and more fully described in Patent No. 2,123,863, issued July 12, 1938, entitled Food Composition and Process of Inhibiting Oxygenation Thereof.

It has now been discovered that this class of phosphatic esters, when added in proper amount to the hydrogenation catalyst, modifies the course of hydrogenation of a vegetable oil in a manner characterized by a shift in the ratio of consistency to iodine value and stability, in such direction as to result in the production of a soft plastic fat, at a specified level of iodine value and stability, as compared with conventional hydrogenation. The phosphatic esters of this invention are effective in concentrations ranging by weight from 20% to 300% of active catalytic metal, but the invention is not necessarily limited to this particular range of concentration, since certain combinations of phosphatic esters and hydrogenation catalysts may exhibit the desired action outside the above range of concentration. Expressing concentration of catalyst in terms of oil under treatment, the probable maximum range is by weight from 01% to 0.5% of vegetable oil, although a percentage of catalyst as high as 1.0% is not prohibitive. The present invention is operable throughout the normal range of hydrogenation conditions, with respect to temperature, pressure, catalyst concentration, hydrogen purity, rate of agitation, and other conditions which are known to affect the rate and selectivity of hydrogenation. However, since one of the main objects of this invention is to produce a soft plastic fat having maximum stability against oxidative decomposition, hydrogenation conditions are preferably chosen to favor selective hardening and to suppress the formation of solid isomers of oleic glycerides. For example, it is well known in the art that selectivity improves with increasing temperature of hydrogenation, up to about 180 0., and decreases with increasing hydrogen pressure, above about 50 lbs. per square inch. Also it is well known that relatively inactive catalysts, or catalysts that have been partially inactivated by poisons such as sulfur, promote the formation of solid isomers of oleic glycerides. Therefore in the application of the present invention to the production of a plastic fat having a maximum degree of stability for a given consistency, a selective, active catalyst would be employed at low pressure and high temperature, above 150 C., with due care to exclude sulfur and analogous catalyst poisons. The pressure may vary from atmospheric to 50 lbs. gauge and the temperature within the range of 150 C. to 200 0.

While nickel or nickel-copper catalysts prepared as herein described, or palladium or platinum, are preferred as hydrogenating catalysts, my process is not dependent for its operativeness on any particular hydrogenating catalyst, but contemplates the use, except where otherwise specifically claimed, of any finely divided metallic catalyst known in the art to be an effective hydrogenating agent for cottonseed, soya, or peanut oil or mixtures thereof.

As an example, 1000 parts of refined, wintered, cottonseed oil (I. V. 116) was mixed with one part of finely divided catalytic nickel and 2 parts of a phosphatic ester prepared according to Example 1 in U. S. Patent No. 2,123,863, dated July 12, 1938. The catalytic nickel was prepared by the conventional process of reducing nickel formate suspended in cottonseed oil, by heating at 240 C. for 3 hours, in a stream of hydrogen, in a closed vessel provided with mechanical agitation. The above mixture of oil, catalyst, and phosphatic ester, along with 3 parts of kieselguhr, was charged into a hydrogenation kettle, equipped with agitator, heating and cooling coils, and hydrogenated at 180 C. under atmospheric pressure, until the iodine value dropped to 66.0. The product, filtered and washed free from nickel, and deodorised with steam under vacuum, was a soft plastic fat at 60 F., having a Wiley melting point of 342 0., setting point of 25.2 C., 60 F. Scoco needle penetration of 34, active oxygen method (A. O. M.) stability of 240 hours, and a solid glyceride content at 20 C. of 29.5% (per cent. solids content determined by dilatometric measurement).

A control sample, hydrogenated and treated under identical conditions except with no phosphatic ester added, had an I. V. of 66.2, Wiley M. P. of 366 0, setting point of 26.0, 60 F. Scoco needle penetration of 26, A. O. M. stability of 160 hours, 31% solids at 20 C., and a consistency of 60 F. that was hard and brittle compared to the preceding sample. Since the treated sample and the control sample were both hydrogenated under the same conditions to the same I. V. 66) comparison of the above results shows clearly that hydrogenation in the presence of the specified phosphatic ester has the unexpected and valuable effect of softening the consistency and increasing the resistance to rancidity at the same time. It will also be observed that the process has a lowering effect on the melting point, which is a very desirable effect in hydrogenated vegetable oils for use in margarine, where it is important to keep the melting point below body temperature.

Another advantage of the product of the process over the control fat is a lower susceptibility to color reversion and flavor reversion upon exposure to air, heat, and light. Still another superiority of the product of the process is a wide plastic range, which means that the consistency or body of shortenings prepared therefrom changes very little over a wide temperature range, this being a valuable property in shortenings and margarines, which should be plastic and workable from 60 to F.

The Scoco 60 F. needle penetration test for consistency is conducted as follows:

The fat sample is melted and dried, then filled into one-ounce metal ointment cups, cooled slowly to incipient cloud point, and then solidified rapidly by placing in a 32 F. compartment for one hour. The cups containing the solidified samples are then placed in a thermostatically controlled 60 F. water bath for one hour. A standard A. S. T. M. grease and asphalt penetrometer is fitted with a special aluminum needle having a conical tip 0.9 cm. diameter at the base and 1.7 cm. in altitude, the total weight of the needle being 24.0 grams. The sample cup is placed on the penetrometer stand and the needle tip is brought to the surface of the fat, at a point approximately midway from the center to the rim of the cup. Then the needle is raised 1 centimeter penetrometer units) and allowed to fall freely for 2 seconds. The depth of plunge is then read directly in penetrometer units (1 unit equals 0.1 mm.).

The setting point or congeal point is deter mined by the method described in U. S. Patent 2,047,530, dated July 14, 1936, page 2.

The per cent. solids at 20 C. are calculated from dilatometric data, described in detail by Coffey and Spannuth, Oil and Soap, February 1940, page 41.

Reference to the active oxygen method for stability has been made in the preceding paragraphs, and the Wiley melting point and iodine value methods are the official methods of the American Oil Chemists Society.

The practice of the process, involving hydrogenation of normally liquid vegetable glyceride oil in the presence of compounds or esters other than those defined in the accompanying claims is without the scope of our invention, since they do not give the combination of properties hereinbefore listed.

While a preferred embodiment of this invention has been described, it is apparent that many variations within the generic disclosure are possible, and these are intended to be included, limited only by the scope of the claims.

What is claimed is:

l. A method of producing a soft plastic fat of superior keeping quality by hydrogenating a nor mally liquid vegetable glyceride oil with a finely divided hydrogenating metallic catalyst in the presence of a phosphatic ester, the latter comprising the ethanol soluble reaction product of a polyhydric alcohol partial fatty ester with phas phoric anhydride, and a primary alkylolamine, represented in part by the general formula in which P is phosphorus, O is oxygen, R. is hydrogen or a lower alkyl group, Y is an alkylolamine radical linked to P through its oxygen, X is a polyhydric alcohol partial fatty ester radical, and n is a small whole number.

2. The method defined in claim 1 in which the percentage of the finely divided metal catalyst is by weight from .01% to about 0.5% of the oil and in which percentage by weight of the phosphatic ester is from 20% to 300% of the catalytic metal.

3. The method defined in claim 1 in which the catalyst is selected from the group consisting of nickel, nickel-copper, palladium and platinum.

4. The method defined in claim 1 in which the normally liquid vegetable glyceride oil is selected from the group consisting of cottonseed, soy, and peanut oils.

5. The method defined in claim 1 in which the process is conducted within a pressure range of 0 to 50 lbs. gauge and at a temperature within the range 150 C. to 200 C.

6. The method defined in claim 1 in which X is a fatty diglyceride radical.

7. The method defined in claim 1 in which X is a fatty monoglyceride radical.

8. The method defined in claim 1 in which X is the radical of a partial fatty ester of polyglycerol.

HARVEY D. ROY CE. LANGDON C. HASKELL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 20 1,890,585 Newton et al Dec. 13, 1932 2,123,863 Royce July 12, 1938 2,363,672 Jakobsen Nov. 28, 1944

Claims (1)

1. A METHOD OF PRODUCING A SOFT PLASTIC FAT OF SUPERIOR KEEPING QUALITY BY HYDROGENATING A NORMALLY LIQUID VEGETABLE GLYCERIDE OIL WITH A FINELY DIVIDED HYDROGENATING METALLIC CATALYST IN THE PRESENCE OF A PHOSPHATIC ESTER, THE LATTER COMPRISING THE ETHANOL SOLUBLE REACTION PRODUCT OF A POLYHYDRIC ALCOHOL PARTIAL FATTY ESTER WITH PHOSPHORIC ANHYDRIDE, AND A PRIMARY ALKYLOLAMINE, REPRESENTED IN PART BY THE GENERAL FORMULA