US2694645A - Stabilization process - Google Patents

Description

United States Patent STABILIZATION rnocnss William K. T. Gleim, Orland Park, Ill., assiguor to Universai Gil Products Company, Chicago, IIL, a corporation of Delaware No Drawing. Appiication February 16, 1952, Serial No. 271,980

20 Qiaims. (Cl. 99-163) This application relates to a stabilization process and more particularly to a method of preventing deterioration of unstable organic substances during storage, transportation or treatment, by incorporating therein a novel inhibitor.

, The present invention is particularly applicable to the stabilization of food products which generally are of animal, vegetable or mineral origin, including edible fats and oils which tend to become rancid, especially during long periods of storage prior to use. Typical representatives of these oils include linseed oil, menhaden oil, cod liver oil, castor oil, olive oil, rapeseed oil, coconut oil, palm oil, corn oil, sesame oil, peanut oil, babassu oil, butter, fat, lard, beef tallow, etc., as well as hydrogenated fats and oils such as are sold under various trade names. It is understood that other oils and fats may be treated within the scope of the present invention, including oils and fats which previously have been subjected to various treatments, such as blowing with air, heat treatment, etc.

Other specific organic substances which undergo deterioration and to which the present invention is applicable include motor fuel and particularly olefinic gasolines such as cracked gasoline and polymer gasoline, etc., kerosene, lubricating oil, diesel oil, fuel oil, etc., drying oils, rubber, plastics, waxes, monomers, resins, adhesives, photographic developers, synthetic unsaturated compounds, etc.

In one embodiment the present invention relates to a method of stabilizing an organic compound subject to oxidative deterioration which comprises adding thereto an inhibitor comprising an alkylated flavone compound having at least one hydroxy substituent.

In a specific embodiment the present invention relates to lard containing, as an inhibitor against rancidity, butylated dihydroquercetin.

I have found that butylation of dihydroquercetin results in an inhibitor compound which is approximately two and one-half times more potent than dihydroquercetin as an inhibitor to retard oxidative deterioration of an organic substance. This unexpected improvement considerablv enhances the feasibility of flavone compounds as inhibitors and furthermore the alkylated compounds are of increased solubility in most substrates. This further enhances the desirability of the use of the flavone compounds as inhibitors.

The alkylated flavone compounds for use in accordance with the present invention may be represented by the following general formula:

Where Y is selected from hydrogen, alkyl or hydroxy groups, and at least one Y is an alkyl group and at least one Y is a hydroxy group.

It will be noted that the numbering of the oxygen and carbon atoms has been indicated. This numbering system will be used throughout the present specifications and claims.

The alkylated flavone compounds of the present in- 2,694,645 Patented Nov. 16, 1954 "ice As hereinbefore set forth, the alkylated flavone compounds of the present invention must contain at least one alkyl group and at least one hydroxy group. Preferred compounds comprise those in which two of the Y substituents are hydroxy groups in a position ortho or para to each other, and one of the Y substituents is a tertiary alkyl group, while the remaining Y is hydrogen. Specific compounds in this group include tertiary alkylated-5,6-dihydroxy flavones, tertiary alkylated-5,8-dihydroxy flavones, tertiary alkylated 6,7 dihydroxy flavones, tertiary alkylated-7,8-dihydroxy flavones, tertiary alkylated-2',3-dihydroxy flavones, tertiary alkylated-2',5'-dihydroxy flavones, tertiary alkylated-3,4- dihydroxy flavones, tertiary alkylated-3',6'-dihydroxy flavones, tertiary alkylated-4',5-dihydroxy flavones, tertiary alkylated-5,6-dihydroxy flavones, etc. Other than the requirement that at least one Y is an alkyl group and the other Y is a hydroxy substituent, the flavone compounds may contain other substituents attached to one or more of the rings. Thus additional inhibitor compounds include alkylated chrysin (alkylated-5,7-dihydroxy flavone), alkylated luteolin (alkylated-5,7,3',4- tetrahydroxy flavone), alkylated quercetin (alkylated- 3,5,7,3',4-pentahydroxy flavone), alkylated myricetin (alkylated-35.73,4',5-hexahydroxy flavone), alkylated rhamnetin (alkylated 3,5,3,4'-tetrahydroxy-7-methoxy flavone), alkylated rhamnazin (alkylated-3,5,4'-trihydroxy-7,3'-dimethoxy flavone), etc. It will be noted that all of the above compounds contain at least two hydroxy substituents.

Also included in the alkylated flavone compounds for use in accordance with the present invention are al kylated flavone compounds having the bridge oxygen in the 1-position and a phenyl group in the 3-position. Flavones having the phenyl group in the 3-position are iso-fiavones and the term isoflavones, therefore, is used in the present specifications and claims to mean a flavone compound having the phenyl ring attached in the 3-position with the bridge oxygen in the 1-position. Also included in the alkylated flavone compounds are alkylated xanthones including such compounds as alkylated euxanthone (alkylated 1,7-dihydroxy-Xanthone), alkylated gentisein (alkylated 1,7-dihvdroxy-3-methoxy-xanthone), etc. It is understood that the alkylated isoflavone and xanthone compounds may be substituted by hydroxy or other substituents as hereinbefore set forth.

When the flavone compound contains a hydroxy substituent in the 3-position, the compound will be a flavonal. The flavonal may be substituted in the manner hereinbefore set forth and thus includes such compounds as alkylated galangin (alkylated-5.7-dihydroxy flavonal), alkylated datiscetin (alkylated 5.7.2 tr ihv dr ox y fiavanol), alkylated kaempherol (alkylated-5.7.4'-trihydroxy fiavanoll, alkylated morin (alkylated-5.7,2',4'- tetrahydroxy flavanol), alkylated quercetagetin (alkylated 5,6,7.3',4 pentahydroxy fiavanol), alkylated gossypetin (alkylated-5.7,8,3'-tetrahydroxy flavanol), etc. Also included in the flavone compounds are alkylated flavanone compounds which may be substituted similarly as described above or otherwise, provided the substituents contain at least one alkyl group and at least one hydroxy substituent. Alkylated dihydroquercetin (alkylated-3,5,7,3',4'-pentahydroxy flavanone) is a preferred compound.

When one Y is hydrogen, one Y is a tertiary alkyl group and the other two Y substituents are hydrogen, preferred compounds include flavones, flavanols, or fiavanones containing the following substituents: 5-hydroxy-6-tertiary alkyl, 6-hydroxy-7-tertiary alkyl, 7-hydroxy-S-tertiary alkyl, 6-hydroxy-5-tertiary alkyl, 7-hydroxy.-6-tertiary alkyl, 8-hydroxy-7-tertiary alkyl, '2"-hydroxy-3'-tertiary alkyl, 3'-hydroxy-4-tertiary alkyl, 4- hydroxy-5'-tertiary alkyl, 5'-hydroxy-6'-tertiary alkyl, 3'- hydroxy-2'-tertiary alkyl, 4'-hydroxy-3-tertiary alkyl, 5- hydroxy-4'-tertiary alkyl, 6'-hydroXy-5'-tertiary alkyl, etc.

The alkylated substitutent preferably comprises an alkyl group, including a branched chain substituent and particularly a tertiary alkyl substituent. Thus the tertiary alkyl group may comprise one or more of tertiary butyl, tertiary amyl, tertiary hexyl, tertiary heptyl, tertiary octyl, tertiary nonyl, tertiary decyl, tertiary undecyl, tertiary dodecyl, etc. Other branched chain alkyl groups include secondary alkyl substituents including secondary butyl, secondary amyl, secondary hexyl, etc., and isoalkyl substituents include isoamyl, isohexyl, etc. In general, alkyl groups containing from 4 to 8 carbon atoms per group are preferred and, when more carbon atom substituents are desired, the substitution preferably is obtained through the use of two or more alkyl groups containing from 4 to 8 carbon atoms per group. In general the total number of carbon atoms in the total substituents preferably does not exceed about 25.

The fiavone compounds specifically set forth above are representative of the large number of compounds which may be employed in accordance with the present invention and are not to be considered as being limited thereto. It will be noted that a large number of different compounds may be employed and that all of these compounds are not necessarily equivalent but that all of them will be eifective in retarding oxidative deterioration of the organic substance.

Alkylation of the fiavone or flavanone compound may be eifected in any suitable manner. Generally the alkylation may be eifected by the reaction of the desired fiavone or flavanone compound with an olefin or an alcohol in the presence of a suitable catalyst. For example, dihydroquercetin may be reacted with tertiary butyl alcohol in the presence of 85% phosphoric acid to form butylated dihydroquercetin. It is believed that this reaction includes both alkylation and dehydration of the dihydroquercetin, thus indicating formation of a fiavone from the flavanone.

The fiavone compound may be obtained from any suitable source or prepared in any suitable manner. For example, dihydroquercetin has been obtained from Douglas fir heartwood. The flavanones may be synthesized from polyhydroxychalcones obtained from suitably substituted benzaldehydes and acetophenones by the Claisen reaction. One hydroxy group must be ortho to the keto group in order to permit closing of the ring. Flavanones also may be synthesized by the reaction of hydroxy acetophenones with acid anhydrides and sodium salts of aromatic acids in a Perkin type reaction.

The inhibitor generally is added to the organic substance to be stabilized in amounts of less than about 1% by weight and preferably within the range of from about 0.0001% to about 0.5% by weight. The inhibitor may be used alone or in conjunction with inhibitor activators or synergists, dyes, antiknock agents, etc., depending upon the organic substance being treated. For example, when used in edible fats and oils, a synergist, such as citric acid, phosphoric acid, ascorbic acid, etc., and perhaps a metal deactivator, may be used along with the inhibitor. On the other hand, when used in gasoline, tetraethyl lead, a metal deactivator, a dye and perhaps an inhibitor activator, such as particular types of alkylene polyamines, may be used.

The following examples are introduced to illustrate further the novelty and utility of the present invention but not with the intention of unduly limiting the same.

EXAMPLE I This example illustrates the improved results obtained by the use of tertiary butylated dihydroquercetin as compared with dihydroquercetin. The butylated dihydro quercetin was prepared by the reaction of dihydroquercetin with tertiary butyl alcohol in the presence of 85% phosphoric acid as hereinbefore set forth.

The lard used for these runs had a normal stability period of 5 hours as determined by the Swift test. This test is described in detail in the article by A. E. King, H. L. Roschen, and W. H. Irwin, which appeared in the Oil and Soap, vol. X, No. 6, pages 105 to 109 (1933). In general, this test comprises bubbling air through a sample of the lard until rancidity is determined organoleptically and by peroxide formation. The results reported in the following table are the number of hours until the lard developed a peroxide number of 20.

It will be noted that the alkylated dihydroquercetin is about 2 /2 times as effective as the unalkylated dihydroquercetin. Furthermore, the alkylated product is more soluble in lard than is dihydroquercetin and, therefore, is considerably more attractive for this use.

EXAMPLE II This example illustrates the results obtained in the stabilization of another sample of the lard as determined in the Schaal oven test. The Schall oven test is a standard test for determining the stability of lard. The lard is maintained in the oven at F., rancidity being determined organoleptically, and the time until rancidity develops is reported in days. The lard had a stability period of 8 days as determined in the Schaal oven test. Upon the addition of 0.02% by weight of tertiary butylated dihydroquercetin, the stability of the lard was increased to 93 days. Thus it is noted that the butylated fiavone compound was a very elfective inhibitor to retard rancidity development.

EXAMPLE III Bacon slabs may be stabilized against rancidity by soaking the slabs in an aqueous solution containing 0.2% by weight of butylated dihydroquercetin.

EXAMPLE IV Corn oil may be stabilized against rancidity by incorporating therewith 0.1% by weight of tertiary hexylated dihydroquercetin.

I claim as my invention:

1. A method of stabilizing an organic substance subject to oxidative deterioration which comprises incorporating therein an alkylated fiavone compound having at least one hydroxy substituent.

2. A method of stabilizing an organic substance subject to oxidative deterioration which comprises incorporating therein a tertiary alkylated fiavone compound having at least one hydroxy substituent.

3. A method of stabilizing an organic substance subject to oxidative deterioration which comprises incorporating therein a teritary alkylated dihydroquercetin.

4. A method of stabilizing an edible fat or oil against rancidity which comprises incorporating therein tertiary butylated dihydroquercetin.

5. A method of stabilizing an organic substance subject to oxidative deterioration which comprises incorporating therein an alkylated fiavone compound having two hydroxy substitutents in a position ortho to each other.

6. A method of stabilizing an organic substance subject to oxidative deterioration which comprises incorporating therein an alkylated fiavone compound having two hydroxy substituents in a position para to each other.

7. A method of stabilizing an organic substance subject to oxidative deterioration which comprises incorporating therein an alkylated fiavone compound having a hydroxy substituent and a tertiary alkylated substitutent in a position ortho to the hydroxy substituent.

8. An organic substance subject to oxidative deterioration containing, as an inhibitor for said deterioration, an alkylated fiavone compound having at least one hydroxy substituent.

9. An organic substance subject to oxidative deterioration containing, as an inhibitor for said deterioration, a tertiary alkylated fiavone compound having at least one hydroxy substituent.

10. An organic substance subject to oxidative deterioration containing, as an inhibitor for said deterioration, tertiary butylated dihydroquercetin.

11. An edible fat or oil subject to oxidative deterioration containing, as an inhibitor for said deterioration, an alkylated flavone compound having at least one hydroxy substituent.

12. An edible fat or oil subject to oxidative deterioration containing, as an inhibitor for said deterioration, an alkylated flavone compound having two hydroxy substituents in a position ortho to each other.

13. An edible fat or oil subject to oxidative deterioration containing, as an inhibitor for said deterioration, an alkylated flavone compound having a hydroxy substituent and a tertiary alkylated substituent in a position ortho to the hydroxy substituent.

l4. Lard containing, as an inhibitor against rancidity, an alkylated flavone compound having at least one hydroxy substituent.

15. Lard containing, as an inhibitor against rancidity, an alkylated flavone compound having two hydroxy substituents in a position ortho to each other.

16. Lard containing, as an inhibitor against rancidity, an alkylated flavone compound having two hydroxy substituents in a position para to each other.

17. Lard containing, as an inhibitor against rancidity, an alkylated flavone compound having a hydroxy substituent and a tertiary alkylated substituent in a position ortho to the hydroxy substituent.

18. Lard containing, as an inhibitor against rancidity, tertiary butylated dihydroquercetin.

19. Vegetable oil containing, as an inhibitor against rancidity, an alkylated flavone compound having at least one hydroxy substituent.

20. Vegetable oil containing, as an inhibitor against rancidity, an alkylated flavone compound having a hydroxy substituent and a tertiary alkylated substituent in a position ortho to the hydroxy substituent.

References Cited in the file of this patent UNITED STATES PATENTS (pages 243-245).

Kurth et al., J. Am. Oil-Chem. Society, October 1951 (pages 433-436).

Claims (1)

1. A METHOD OF STABILIZING AN ORGANIC SUBSTANCE SUBJECT TO OXIDATIVE DETERIORATION WHICH COMPRISES INCORPORATING THEREIN AN ALKYLATED FLAVONE COMPOUND HAVING AT LEAST ONE HYDROXY SUBSTITUENT.