US3189628A - Phosphonated oils and phosphonated esters - Google Patents

Description

United States Patent F 3,189,628 PHQSPHONATED GILS AND PHGSPHONATED ESTERS Hogan B. Knight, Ambler, and Daniel Swern, Philadelphia, Pa., assignors to the United States of America as represented by the Secretary of Agriculture N0 Drawing. Filed Feb. 27, 1962, Ser. No. 176,157 25 Claims. (Cl. 269--403) (Granted under Title 35, US. Code (1952), sec. 266) A non-exclusive, irrevocable royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

Thisinvention relates to alkyl phosphonate derivatives of alkyl and glyceryl esters of polyunsaturated acids or mixtures containing them, and to a process for their preparation.

The esters of polyunsaturated fatty acids have heretofore behaved as inhibitors and have been essentially unreactive in peroxided initiated synthetic addition reactions, thus limiting free radical reactions conducted in their presence. The inhibitory effect is assumed to be caused by the presence in polyunsaturated fatty acids, such as linoleic and linolenic acids, of highly reactive allylic systems which are converted on reaction with free radical generating sources, to sluggishly reactive radicals. These sluggishly reactive radicals prefer to dimerize rather than to add other species to their double bond systems. The radicalinhibiting effect of glyceryl esters of polyunsaturated fatty acids is also shown by alkyl esters of polyunsaturated fatty acids.

Therefore, the discovery that dialkyl phosphonates can be added in good yield to the double bonds of polyunsaturated fatty acid moieties in alkyl esters and in glyceryl esters is unexpected.

In general, according to the present invention polyphosphonate derivatives of esters of polyunsaturated fatty acids are prepared by the free radical addition of dialkyl phosphonates to alkyl and glyceryl esters of polyun saturated fatty acids or to mixtures containing them.

The dialkyl phosphonates are compounds of the formula H (RO) Il )O wherein R is an alkyl radical. Although the alkyl groups, R may be different instead of identical and may contain less than 2 and more than 8 carbon atoms, the invention is exemplified with dialkyl phosphonates in which a straight chain or branched chain alkyl radical contains 2 to 8 carbon atoms, such as ethyl, butyl and 2- ethylhexyl, because of their availability and price.

Similarly, the alkyl esters of a polyunsaturated acid are exemplified with ethyl, butyl and Z-ethylhexyl esters, but many other straight and branched chain alkyl radicals may be the alkyl group in the alkyl ester of the polyunsaturated fatty acid from which the polyphosphonated derivative is prepared.

The polyunsaturated fatty acids are typically represented by the diunsaturated acid, linoleic, and the triunsaturated acid, linolenic. Other fatty acids may be selected for use from among thefollowing:

Sorbic 2,4decadienoic 3,l89,28 Patented June 15, 1965 ice 9,15-octadecadienoic 2,4-dodecadienoic 10,13-nonadecadienoic l l, l4-eicosadienoic 17,20-hexacosadienoic 6,10,14-hexadecatrienoic (hiragonic) 7,l(),l3hexadecatrienoic Cis-6, cis-9, cis-lZ-octadecatrienoic C is-9, trans-1 1, trans l3-oetadecatrienoic (u-eleostearic) Trans-9,trans-11, trans-13-octadecatrienoic (B-eleostearic) Cis-9, cis-l l, trans-l3-octadecatrienoic (punicic) 9, 12, l4-octadecatrienoic Trans-9, trans-12, trans-1S-octadecatrienoic (linolenelaidic) Trans-10, trans-12, trans-14-octadecatrienoic (pseudoeleostearic) 10, 12, IS-Octadecatrienoic 5, 8, ll-eicosatrienoic 8, ll, l4-eicosatrienoic 7, 10, 13-docosatrienoic 8, 11, 14-docosatrienoic 4, 8, 11, l4-hexadecatetraenoic 6, 9, l2, IS-hexadecatetraenoic 4, 8, 12, IS-octadecatetraenoic (morotic) 9, 11, 13, lS-octadecatetraenoic (u-parinaric) 9, i1, 13, lS-octadecatetraenoic (,8'parinaric) 4, 8, l2, 16-eicosatetraenoic 5,8,11, l4-eicosatetraenoic 4,7,10,13-docosatetraenoic 7,10,13,l-docosatetraenoic 8,12,16,19-docosatetraenoic 4,8,12,13,16-docosapentenoic 4,8,12,15, l9-docosapentenoic (clupanodonic) Tetracosapentenoic (scoliodonie) Hexadosapentenoic (shibic) 4,7,10,13,16,19-docosal1exaenoic 4,8,12, 1 5,18,21-tetracosahexaenoic (nisinic) The addition of a dialkyl phosphonate to a polyunsaturated fatty acid, here exemplified With an alkyl linoleate, is illustrated showing one of the isomeric products:

l excess (R O)3P. 0

Radical 1 source In a preferred embodiment of the invention an amount of dialkyl phosphonate in excess of that which will add to the double bonds is combined with the ester of the unsaturated fatty acid. A molar excess of the dialkyl phosphonate is recommended for optimum yields and maximum rates of reaction. Since the excess phosphonate can be recovered by vacuum distillation at the end of the reaction and reused, a general procedure was adopted in most cases using about three moles of dialkyl phosphonate volatilesare 'recoveredby vacuum stripping.

double bond in" the fatty acid, and the dialkyl phos- Alterna tivery, by using lesser quantities of dialkyl phosphonates phonate served both as solvent and reactant.

per double bond it is-possible to add the dialkyl phospho- -nate to a controlled number of available double bonds. .The products, phosphonates still containing residual unsaturation, can be epo xidized or otherwise reacted at the double bonds remaining.

sneaeaa Tertiary butyl peresters are preferred initiators'for the addition'reaction because their decomposition characteristics are suitable for initiating the reaction in the tempera- "ture range in which the polyunsaturated esters are activated and prefer to undergo addition of phosphonate rather than to dimerize or react in other undesirable fashion. Tertiary butyl perbenzoate is a preferred initiatorbecause of its relatively low cost and high efficiency.

1 Approximately mole percent of initiator based on unsaturated ester is usually employed. Benzoylperoxide, (ii-tertiary butyl peroxide and azobisisobutyronitrile are not as eliective initiators as are the peresters.

The reactants and initiator may be combined in various ways to obtain good yields from the addition reaction. In one convenient method, the polyunsaturated ester, diallgylphosphonate and a portion of the initiator (515% 3 of the total amount to be used) are mixed and h eated at 90-100? in an inert atmosphere with more-or-less equal incremental additions of initiator at one to two hour intervals fora total reaction period of to hours, depending on the unsaturated ester. Alternatively, (a).the polyunsaturated ester at room temperature and containing 'the: total quantity of initiator is added slowly to the stirred dialkyl phosphonate, heated to reaction mixture and maintained in an inert atmosphere or, (b) the addition is conducted as in (a) except that a portion of the dialkyl phosphonate is used as a diluent and solventfor the polyunsaturated ester, and they are added simulta neously from a dropping funnel to the remainder of the dialkyl phosphonate; in the reaction vessel at reaction temperature. 'By operating as in (a) or (b), alarge excess of dialkyl phosphonate'is always present with respect to the polyunsaturated fatty ester being added; and, also, there is a uniform concentration of initiator being added at all times to the reaction. By the incremental addition of initiator, it' is present in markedly varying amounts.

'By all three reaction procedures, however, yields are usually high and are about thesame. At the conclusion of the reaction, the excess dialkyl phosponate and other groups, the derivative of an arachidonate ester contains four, and esters of fatty acids with greater degrees of unsaturation will add correspondingly more diaikylphosphono groups. V a

The addition of the dialkylphosphono groups to polyfatty acids are contained in natural and synthetic triglycerides.

safliower, corn, sunflower, tung and linseed oils, fish oils, tallow, lard, lard oil and oleo oil.

The glyceryl ester formed from two stearic acids and onelinoleic acid could add a maximum of two dialkylphosphono groups. A triglyceride containing ten double bonds (two linolenic and one arachidonic acids) could add as many as ten dialkyl- Infrared Some typical natural triglycerides to which V dialkyl phosphonates add readily are soybean, cottonseed,

7 These triglycerides are mixed glyceryl esters of saturated, monounsaturated,

and polyunsaturated fatty acids. It is readily apparent that products with a' wide range of phosphorus content made he obtained from triglycerides.

' unsaturated'fatty acids proceeds in high yields when the age phosphorus content can be prepared by using a mixture of natural or synthetic glycerides having a certain average degree ofunsatur'ation, or by blending the addition products to achieve a similar result. Alternatively, by limiting the reaction time or the quantity ofdialkyl phosphonate residual unsaturation can be left in the molecule p Y '7 The following examplescorresponding to 13 and 21, respectively, of Table I, are typical illustrations of the preparation of a dialkyl' phosphonate addition product.

EXAMPLE. A 7 V Dibutyl phosphonate, 90.7 g. (0.47 m.) and cottonseed oil, 33.0 g. were placed in a 250 ml. round-bottbmfinecked flask equipped with a magnetic stirrer, a nitrogen inlet tube, and'thermometer. The contents of the 'fiask were heated to C., with stirring, and 0.3 g.- of t-butyl perbenzoate was added. The temperature was maintained between 100 and C., with stirring, in an atr nosphere' of nitrogen, andadditional t-butyl perbenzoate, 0.3. g.,

was added at 2 hour intervals (ifei 2,"4;"6;8, etc lhrq l h V mercury pressure to remove the excess di-butyl phosphonate and any volatiles. The final product was isolated as the residue from the stripping action-ofa arotatingbrush, falling-film type molecular distillation unit operated The yield of" up to 150 C. at 10 mercury pressure; product was 58.5 g. (92.7 of theoretical). Phosphorus analysis: calculated, 7.61%; found, 7.44%. (This example corresponds to Example 13 of Table I.)

EXAMPLE. B a

Diethyl phosphonate, 46.0 gross m.) and1lard,43.2j g. were treated as in Example A, except that 3.5 g. of:

t-butyl perbenzoate was used as the catalyst and the reaction time was 20 hours. in Example A weighed 53.0 g. (90.4% of theory) Phosphorus analysis: calculated, 5.7%; found,:6.4%. (This example corresponds to Example 21' of Table 1.): Other examples were carried out in a similar manner; the principal variation in procedure being in reaction time, as indicated in the results present in Table I. V

The utility of the products of the present invention is 7 related to the number of dialkylphosphono groups added l to double bonds of alkyl and glyceryl esters of polyun saturated fatty acids and not with the particular isomeric configurations of the addition products. 7 For example, the four position isomers of a linoleate (9,12; 10,12; 10,13;

and 9,13) contain two dialkylphosphon'o' groups.

Table I. Ph0sph0na ted triglycerides and phosphonated synthetic esters p R i Products Ioeac- Exam- Reactauts 8 tion hi d? ple N 0. Time, Yield, Phos Hrs. Perphorus,

cent 7 Percent V 1 Ethyl Linoleate 1N0. so a l 163.5) and Diethyl 9 6a 75 1 2 B Pthlisghoriate. s u y ino eate (I No. 30

142.5) and Di-2- 87 85 7 Ethylhexyl Phospho- 3' iiiir 'm 1r. 1 I

.r i y exy ino eate 30 83 i (I N o. and Di-2- 6 8 Ethylhexyl Phospho- 4 Eiif i Lin 1 t (I y o ena e 40 40 a a No. 226) and Diethyl 8 5? 42 5 BPhgsIpyhoriate. (I V e uty i110 enate 40 44 i a v No. 225) and Diethyl 6 77 54 g y exy inole- 40 72 mate (I No. 174) and V 5 03 29 Dibutyl Phosphonate.

See footnote at end or table.

The product isolated exactly as Products 10- dine No.

Reactlon Time, Yield,

Hrs. Percent Exam- Reactants B ple No. Phos phorus,

Percent Bntyl Esters of Tall Oil 30 84 7. 23 4. 5

Fatty Acids (I No. 110) and Dibutyl Phosphonate.

2-Ethylhexyl Esters of Tall i] Fatty Acids and Dibutyl Phosphonate.

Soybean Oil (I No. 144) and Diethyl Phosnate.

Soybean Oil and Di-2- Ethylhexyl Phosphonate.

Butyl Esters of Soybean Oil Fatty Acids No. 119) and Dibutyl Phosphonatc.

Cottonseed Oil (I No. 118.5) and Diethyl Phosphonate.

Cottonseed Oil and Dibutyl Phosphonate.

Ethyl Esters of Cottonseed Oil (I No. 105.6) and Di-2-Ethy1hexyl Phosphonate.

2Ethy1hexyl Esters of Cottonseed Oil (I No. 82) and Di-2Ethylhexyl Phosphonate.

Safllower Seed Oil (I No. 145) and Diethyl Phosphonate.

Z-Ethylhexyl Esters of Safllower Seed Oil (1 N o. 109) and Dibutyl Phosphonate.

Butyl Tallate (I No. 110) and Dibutyl Phosphonate.

2-Ethylhexyl Tallate (I No. 93.4) and Dibutyl Phosphonate.

Oleo Oil (I No. 46.5) and Diethyl Phosphonate. Lard (I No. 65.5) and Diethyl Phosphonate. Lard and Dibutyl Phoe phonate. Oleo Oil and Dibutyl Phosphonate.

Lard and Di-Z-Ethylhexyl Phosphonate. Oleo Oil and Di-QFE thylhexyl Phosphonate.

a Three moles of dialkyl phosphonate were used per mole of double bond at a reaction temperature of 90-110". Tertiary butyl perbenzoate was used as initiator (5 mole percent based on unsaturated compound). At the end of the initiated reaction period all volatiles were stripped under high vacuum (1 mm. or less), and the residual products were analyzed for phosphorus content and iodine number.

When adding the maximum number of dialkylphosphono groups to a linolenate there is. the possibility of eight isomers, to an arachidonate, sixteen isomers, etc.

The phosphorus-containing esters are useful as lubricant additives for improving the wear and extreme pressure properties of petroleum and of synthetic diester lubricants. Some of the dialkyl phosphonate addition products are useful plasticizers for polyvinyl chloride resins, especially the addition products derived from alkyl esters of polyunsaturated fatty acids.

As an illustration of the utility of the new phosphoruscontaining triglycerides and synthetic esters, Table II shows the improvement in the wear properties of an additive-free paraflin base lubricating oil and of a synthetic diester base fluid lubricant (di-2-ethylhexyl sebacate) when only 5% of phosphorus-containing ester is added. It is evident that many of the new phosphorus-containing products are eifective Wear additives for parafiin base and synthetic fluids. Especially effective are Examples 11, 12, 13, 20, 24 and 25, although others are moderately effective (Examples 7, and 22).

Table ll.lmprovement in wear properties of parafiin oil and of synthetic diester lubricant by use of 5% of phosphonated triglycerides or phosphonated synthetic esters Phosphonated Product Scar From Table I 7 Base Fluid Diameter,

Paraflin Base Oil Synthetic Fluid Paraffin Base Oil Synthetic Fluid Paraffin Base Oil Synthetic Fluid.-.

Control, No Additive Example:

Synthetic Fluid; Paraffin Base Oil Synthetic Fluid.

23 {Paraffin Base 011. Synthetic Fluid 24 aratfiuBase O Synthetic Fluid Synthetic Flllld :Standard test with Shcll-Boerlage four-ball wear tester; 1 hour 0.; applied load 50 kg.; SKF 1/2 inch, grade 25, steel balls.

We claim:

1. A compound selected from the group consisting of the addition product of a dialkyl phosphonate to an alkyl ester of a polyunsaturated fatty acid, and the addition product of a dialkyl phosphonate to a glyceryl ester containing at least one polyunsaturated fatty acid moiety.

2. A compound selected from the group consisting of the addition product of a dialkyl phosphona-te to an alkyl ester of a polyunsaturated fatty acid and mixtures thereof.

3. The compound of claim 2 in which the dialkyl phosphonate is diethyl phosphonate and the alkyl ester is ethyl linoleate.

4. The compound of claim 2 in which the dialkyl phosphonate is di-Z-ethylhexyl phosphonate and the alkyl ester is butyl linoleate.

5. The compound of claim 2 in which the dialkyl phosphonate is di-Z-ethylhexyl phosphonate and the alkyl ester is Z-ethylhexyl linoleate.

6. The compound of claim 2 in which the dialkyl phosphonate is diethyl phosphonate and the alkyl ester is butyl linoleate.

7. The compound of claim 2 in which the dialkyl phosphonate is dibutyl phosphonate and the alkyl ester is 2- ethylhcxyl linolenate.

8. A compound selected from the group consisting of the addition product of a dialkyl phosphonate to a glyc eryl ester containing at least one polyunsaturated fatty acid moiety.

9. The compound of claim 8 in which the dialkyl phosphonate is diethyl phosphonate and the glyceryl ester is soybean oil.

10. The compound of claim 8 in which the dialkyl phosphonate is di-Z-ethylhexyl phosphonate and the glyceryl ester is soybean oil.

11. The compound of claim 8 in which the dialkyl phos phonate is dibutyl phosphonate and the glyceryl ester is cottonseed oil.

12. The compound of claim 8 in which the dialkyl phosphonate is diethy-l phosphonate and the glyceryl ester is salflower seed oil.

13. The compound of claim 8 in which the dialkyl phosphonate is di-2-ethylhexyl phosphonate and the glyceryl ester is oleo oil.

14. The compound of claim 8 in which the dialkyl phosphonate is di-Z-ethylhexyl phosphonate and the glyceryl ester is lard.

1. r 15. A process for the preparation, of a ,dialkyl phosphonated derivative of an ester of a polyunsaturated fatty acid comprising the free radical addition of a dialkyl V 'phosphonate to at least one double bond in a polyunsat- "Mnated fatty acid-containing'compound selected from the group consisting of an alkyl ester of a polyunsaturated 1 fatty acid and a g'lyceryl ester containingat least one polyunsaturated fatty acid moiety. 7 I a 16. The process of claim 15 in which the alkyl ester is a butyl ester of tall oil fatty acids. a

a :17. The processof claim 15 in which the polyunsaturated fatty'acid-containing compound is a Zethylhexyl ester of cottonseed oil fatty acids. 7

18. The process of claim 15 lnwhich the'polyunsatu-rated fatty acid-containing compound is a Z-ethylhexyl ester of safiiower seed oil fatty acids.

19.. The process of claim 15 in which the glyceryl ester is lard. 1

29. The process of claim 15 in which the glyceryl ester is'saffiower seed oil. 7

21. The process of claim 15 in which the dialkyl phosphonate is dibutylphosphonate and the polyunsaturated fatty acid-containing compound is the 2-ethylhexy1 ester of tall oil fatty acids. a

22. The process of claim 15 in which the dialkyl phosphonate is dibutyl phosphonateand the polyunsaturated fatty acid-containing compound is'the butyl ester'of soybean oil fatty acids. 1 a V *23. The process of claim 15 in which the dialkyl phosphonate is di-Z-ethy-lheXyl phosphonate and the polyunsaturated fa'tty acid-containing compound is soybean oil.

24. The process of claim 15in which the'dialkyl phosphonate is diethyl phosphonate and the polyunsaturated V fatty acid-containing compound is cottonseed oiL; a

25. The process of claim 15 in which the dialkyl phosphonate is diethyl phosphonate and the polyunsaturated fatty acicLcontaining compound is safflower'oil.

References Cited by the Examiner UNITED STATES PATENTS 2,271,127 1/42 Mattikow 260-403 2,466,393 4/49 Dickey et al.'.. 2601-403 2,486,493 11/49 Revukas 252.49.8 2,549,377 4/51 Kemmerer 252 -49.8 2,957,931 10/60 Hamilton 61: a1. '260403 Swern etal. a 260-403 'VCHARLES B. PARKER, Primary Examiner.

DANIEL D. HORWITVZ, Examiner.

Claims (1)

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF THE ADDITION PRODUCT OF A DIALKYL PHOSPHONATE TO AN ALKYL ESTER OF A POLYUNSATURATED FATTY ACID, AND THE ADDITION PRODUCT OF A DIALKYL PHOSPHONATE TO A GLYCERYL ESTER CONTAINING AT LEAST ONE POLYUNSATURATED FATTY ACID MOIETY.