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Publication numberUS3412028 A
Publication typeGrant
Publication dateNov 19, 1968
Filing dateDec 13, 1966
Priority dateDec 13, 1966
Publication numberUS 3412028 A, US 3412028A, US-A-3412028, US3412028 A, US3412028A
InventorsArthur W Godfrey
Original AssigneeTexaco Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Synthetic ester base lubricating composition containing a copper or cobalt acetylacetonate
US 3412028 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

United States Patent SYNTHETIC ESTER BASE LUBRICATING COM- POSITION CONTAINING A COPPER OR CO- BALT ACETYLACETONATE Arthur W. Godfrey, Fishkill, N.Y., assignor to Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 13, 1966, Ser. No. 601,336 5 Claims. (Cl. 25242.7)

ABSTRACT OF THE DISCLOSURE A synthetic lubricating oil composition for turbine engines is disclosed comprising a synthetic base oil and a metal bis(trifluoroacetylacetonate) from the class consisting of copper (II) and cobalt (II) in an amount ranging from 0.01 to 1.0 weight percent based on the weight of the lubricating oil composition.

This invention relates to a lubricating composition designed for the lubrication of turbine engines which operate over a wide temperature range and under severe operating conditions. More particularly, this invention relates to a synthetic lubricating oil composition having good deposit-inhibiting and oxidation resisting properties.

Synthetic base lubricants have been found to be useful for the lubrication of modern high performance turboprop, turbojet and turbofan engines. However, even these superior base oils must be modified to meet the stringent performance requirements set by .the military and by commercial aircraft engine manufacturers. It is particularly difficult to achieve a synthetic oil composition having all the properties to withstand extreme thermal and oxidative stress without laying down deposits and becoming corrosive due to excessive oxidation of components of the synthetic oil.

Various additives and additive combinations have been employed to formulate synthetic lubricating oil compositions. Unfortunately, many of the compounded synthetic lubricating oils tend to promote corrosion of vital metal components of turbine engines, do not sufiiciently inhibit oxidation of the synthetic oil base, or have an unsatisfactory level of deposit laydown and/or load-carrying properties. Deposit laydown and corrosiveness have been particularly severe problems with halogen-containing additives. A synthetic lubricating oil composition has now been discovered which has superior oxidation resistance and deposit inhibiting properties while retaining an effective high level or over-all lubricating properties.

The lubricating composition of this invention broadly comprises a synthetic base fluad having lubricating properties containing a metal derivative of bis(trifluoroacetylacetonate). More specifically, the additive is a metal bis- (trifluoroacetylacetonate) from the class of metals consisting of copper (II) and cobalt (II). The additive is employed in an amount ranging from about 0.01 to 1 weight percent based on the Weight of the lubricating oil composition, the preferred concentration being from 0.05 to 0.3 weight percent. In a preferred form of this invention, the synthetic lubricating oil composition also contains a hydrocarbyl amine antioxidant to further enhance the extremely low deposit laydown of the lubricating oil composition.

The function of the particular bis(trifluoroacetylacetomates) of this invention appears to be unique. Metal acetylacetonates, in general, have been unsatisfactory in lubricating oil compositions because of the formation of and deposition of solids from the oils. Likewise, the use of fluorine-containing additives in lubricating oils has produced compositions having unacceptable high levels of corrosion. The properties of bis(trifluoroacetylacetonate) "ice copper (III) and cobalt (11) appear to be unique even within the class of metal trifluoroacetylacetonates in that they impart good oxidation resistance and deposit laydown properties.

Synthetic ester-type base synthetic fluids are preferred for the lubricating composition of the invention. The base can be an aliphatic diester of an organic dicarboxylic acid. The dicarboxylic acid component is usually an aliphatic dicarboxylic acid containing 6 to 12 carbon atoms although glutaric acid esters and succinic acid esters can also be used. From the standpoint of cost and availability, the dibasic acids, adipic acid, sebacic acid and azelaic acid are favored. The aliphatic alcohols used to form the diesters usually contain at least 4 carbon atoms and may contain 20 or more carbon atoms, with C to C alcohols being preferred.

Specific examples of the dialkyl esters of aliphatic dicarboxylic acids are as follows: di-isooctyl azelate, di- 2-ethylhexyl sebacate, di-Z-ethylhexyl azelate, di-Z-ethylhexyl adipate, dilauryl azelate, di-sec-amyl-sebacate, di- Z-ethylhexyl alkenylsuccinate, di-Z-ethoxy ethyl sebacate, di-2-(2'-methoxyethoxy) ethyl sebacate, di-2(2'-butoxyethoxy) ethyl alkenylsuccinate, etc.

In addition the aliphatic dicarboxylic acid esters described above, polyesters and complex ester lubricants formed by a reaction of an aliphatic dicarboxylic acid, a glycol and a monofunctional compound which is either an aliphatic monohydroxy alcohol or an aliphatic monocarboxylic acid in specified mole ratios are also employed as a synthetic lubricating base in the composition of this invention. Polyesters of this type are described in US. 2,628,974. Complex esters by reaction of a mixture containing specified amounts of 2-ethyl-l,3-hexane-diol, sebacic acid and 2-ethyl hexanol, and by reaction of a mixture containing adipic acid, diethylene glycol and 2-ethylhexanoic acid illustrate this class of synthetic polyester lubricating base.

Esters formed by the reaction of a monocarboxylic acid and a glycol or polyol may also be used as the ester components. The acid component is usually an aliphatic acid containing 3 to 20 carbon atoms and preferaly 4 to 10 carbon atoms. The glycol or polyol component is advantageously a straight glycol, such as 1,5-hexane diol, but ether glycols, such as tetraethylene glycol may also be used. Sterically hindered neopentyl type glycols, such as Z-methyl, Z-ethyl, 1,3-propanediol, are favored for enhanced thermal stability.

Specific examples of the diesters of glycols are the following: di-n-decanoate of 1,4-butanediol, di-Z-ethylhexanote of 1,6-hexanediol, dilaurate of 1,4-hexanediol, dioctanoate of 1,5-pentanediol. Examples of triesters are trimethyl propane triheptanoate and trioctanoate. Examples of tctraesters are pentaerythritol tetracaproate and pentaerythritol esters with mixtures of aliphatic acids generally containing from three to ten carbon atoms.

Complex esters formed by reacting trimethylol and tetramethylol alkanes with various mole ratios of dibasic acids and monobasic acids or alcohols are other examples of polyesters useful for the base fluid of the lubricants of this invention. Pent-aerythritol tetraesters of C aliphatic carboxylic acids are a preferred class of polyester lubricating oils. Polyphenyl ethers are also suitable for the lubricating oil base.

The optional antioxidant component for enhancing the deposit forming properties of the lubricating oil of the invention comprises an aromatic amine having the formula:

3 4 in which R is an alkyl radical having from 1 to 8 carbon grade pentaerythritol esterified with a mixture of 38% atoms, R is hydrogen or an alkyl radical having from 1 valeric, 13% Z-methylpentanoic, 32% octanoic and 17 to 6 carbon atoms and R" is hydrogen, or a phenyl, pelargonic acid. This base fluid had the following propernaphthyl, aminophenyl or an .alkyl-substituted phenyl ties: radical in which the alkyl radical has from 1 to 8 carbon atoms. Examples of these antioxidants include p-p'-di- Viscosity, cs. at 210 F 4.93 octyl diphenylamine, N-phenyl-l-naphthylamine, N- Viscosity, cs. at 100 F 25.6 phenyl-p-phenylene diamine, N-N'-diphenyl-p-phenylene Viscosity, cs. at -40 F. 7023 diamine, N,N-bis(octylphenyl)-p-phenylene diamine, p- Viscosity index 131 hydroxy-diphenylamine, N-phenyl-N-isopropyl-p-phenyl- 10 Flash, F. 490 ene diamine, and N,N'-dioctyl-p-phenylene diamine. The

amines are employed in amounts ranging from 0.1 to The synthetic lubricating oil of the invention was preabout 5 percent by weight of the lubricant composition pared by mixing the additive into the base oil. The properwith the preferred amount being from about 0.5 to 3 ties of the lubricating oils of the invention and of the percent. base oil are given in Table I below:

TABLE 1 Base Oil+0.1% Base Oil+0.1% bis(trifluoro- Base 0il+0.1% Base Oi1+0.1% Base Oi1+0.1%

bis(trifluoroacetyltris(trifluorobis(trifiuorobis(trifluoro- Base Oil acetylaeetonate) acetylaeetylacctylaceacetonate) Cu(II) 1% p,paeetonate) acetonate) tonate) Co(II) Cu(II) deoctyldi- Fe(III) Mgul) phenylamine 450 F. Antioxidant Test: Percent Vis. increase:

24 hours 700 77.6 505 438 48 hours 326 4, 000 Total Acid No.1

24 hours. 6. 5 3. 0

48 hours 19. 4 5. 5 600 F. Oil Mist Test, g. deposit/1,000 g. oil 13.9 0.8 0.1 27. 5 s. s 3. 2(590 F.)

1 Semi-solid.

2 Solid.

Other additive components can be advantageously in- The foregoing data show that the lubricating oil of the corporated in the lubricant composition of the invention. invention was greatly improved in essential lubricating For example, it is conventional to add small concentraand deposit forming properties while oil compositions contions of methacrylate polymers to improve dispersancy. taining similar additives were substantially degraded or An anti-foam agent, such as a hydrocarbon or kerosene rendered totally ineffective. concentrate of dimethyl silicone in an amount ranging Obviously, many modifications and variations of the. from about 0.0001 to 0.01 percent by weight, is generally invention, as hereinbefore set forth, may be made withadded to the lubricating oil. Detergents, such as the metal out departing from the spirit and scope thereof, and theresalts of phenates and sulfonates, are also used to advanfore only such limitations should be imposed as are inditage. In particular, barium sulfonates have been found cated in the appended claims. useful since they inhibit corrosion and rusting. I claim:

The oxidation-corrosion resistance and deposit forming 1. A synthetic lubricating oil composition comprising properties of the lubricating oils of the invention were a major portion of a synthetic ester base having lubricatdetermined in the following tests. ing properties and deposit and oxidation reducing amounts The 450 F. Antioxidant Test is conducted in accordof a metal bis(trifiuoroacetylacetonate) additive, said ance with method 5308.4 of Federal Test Method Standmetal being selected from the class consisting of copper ard No. 791a (issued Dec. 31, 1961) except for certain (II) and cobalt (II). modifications to conform to Pratt and Whitney Aircraft 2. A lubricating oil according to claim 1 containing Specification 521-B (Type II). The bath temperature is from 0.01 to 1 weight percent of said metal bis(trifiuoromaintained at 450 F.i1 F., instead of at 250 F. This acetylacetonate).

test was run for 48 hours with determination of viscosity 3. A lubricating oil according to claim 1 in which said increase and total acid number taken at 24 hours and 48 additive is bis(trifluoroacetylacetonate) copper (II).

hours. 4. A lubricating oil according to claim 1 in which said The Oil Mist Test was described in a paper presented at synthetic oil base is an ester base lubricating oil.

the ASLE/ASME Lubrication Conference in Minneapolis, 5. A lubricating oil according to claim 4 in which said Minn., Oct. 18-20, 1966 by Bartholomaei, Massey and synthetic oil base is an ester pentaerythritol. Holstedt. This test is conducted by passing a mist of oil through a glass tube containing a steel liner (shim stock) References Cited through the entire length of the tube. The tube is main- UNITED STATES PATENTS tamed at 600 F. while the 011 mlst 1s contlnuously passed through over a period of 16 hours. At the end of the 2323932 12/1940 Tfwvne test period, the steel liner is removed, solvent washed and 2,305,627 12/1942 LmFoln at 252-427 X weighed. The amount of tenacious material adhering to i g g -gth liner i det rm'ned and 's re orted as a s f d 0c e s e 1 1 p gr m Q G 3,360,467 12/1967 McHugh et a1. 2s2 74 posit per one thousand grams of oil put through the system. This test represents the formation of breather tube deposits in a jet engine DANIEL E. WYMAN, Primary Examiner.

The base oil employed in the tests below was technical W. H. CANNON, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2223932 *Dec 20, 1937Dec 3, 1940Texas CoLubricating oil
US2305627 *May 24, 1939Dec 22, 1942Lubri Zol Dev CorpLubricating oil
US2465296 *Sep 20, 1944Mar 22, 1949Westinghouse Electric CorpMetal chelate stabilized organic silicon compositions and products thereof
US3231497 *Apr 30, 1963Jan 25, 1966Monsanto Res CorpPolyphenyl ether blends
US3360467 *Mar 29, 1965Dec 26, 1967Monsanto Res CorpFunctional fluid
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4122033 *Nov 26, 1976Oct 24, 1978Black James FOxidation inhibitor and compositions containing the same
US4335006 *Oct 6, 1980Jun 15, 1982Uniroyal, Inc.Method of stabilizing lubricating fluids
DE2731217A1 *Jul 11, 1977Jun 1, 1978Exxon Research Engineering CoOxydationsverhinderer und verfahren zum stabilisieren organischer verbindungen
WO1996012779A1 *Oct 25, 1995May 2, 1996Exxon Research And Engineering CompanyNovel cobalt containing deposit control additives