US3696128A

US3696128A - Perfluoropolyether esters of quinones

Info

Publication number: US3696128A
Application number: US44649A
Authority: US
Inventors: Bruce Hollis Garth
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1970-06-08
Filing date: 1970-06-08
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03

Abstract

Perfluoropolyether esters of quinones having the formula (RfO(CmF2mO)nCF(V)COO)pQ, Q(OC(O)CF(V)(OCmF2m)OR''fO(CmF2mO)nCF(V)COO)Q, or Q(OC(O)CF(V)O(CmF2mO)nCF(V)COO)Q wherein Rf is a perfluoroalkyl group having from one to six carbon atoms, m is an integer of from 1 to 3, n is from 0 to about 20, R''f is a perfluoroalkylene group having from two to 10 carbon atoms, V is F or CF3, Q is a quinone radical and p is the number of hydroxyl groups on Q which are esterified; and fluorinated oils containing these esters.

Description

United States Patent Garth [54] PERFLUOROPOLYETHER ESTERS OF QUINONES [72] Inventor: Bruce Hollis Garth, Newark, Del.

[73] Assignee: E. I. du Pont de Nemours and Company, Wilmington, Del.

22 Filed: June 8, 1970 21 Appl.No.: 44,649

[52] US. Cl. ..260/376, 252/54.6, 260/368, 260/396 R [51] Int. Cl ..C07c 69/66 [58] Field of Search ..260/376, 396 R, 368, 535

[56] References Cited UNITED STATES PATENTS 3,250,807 5/1966 Fritz et a]. ..260/535 3,250,808 5/1966 Moore et al. ..260/535 3,250,806 5/1966 Warnell ..260/535 51 Oct. 3, 1972 Primary Examiner-Lorraine A. Weinberger Assistant Examiner--E. Jane Skelly Attorney-Nicholas J. Masington, Jr.

[57] ABSTRACT Perfluoropolyether esters of quinones having the formula Q[ m 2m )n )COO]Q wherein R, is a perfluoroalkyl group having from one to six carbon atoms, m is an integer of from 1 to 3, n is from 0 to about 20, R, is a perfluoroalkylene group having from two to 10 carbon atoms, V is F or CF;,, Q is a quinone radical and p is the number of hydroxyl groups on O which are esterified; and fluorinated oils containing these esters.

10 Claims, No Drawings BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to novel perfluoropolyether esters of hydroxy quinones which are useful as stabilizers in fluorinated oils'to reduce degradation of these fluorinated oils at high temperatures, e.g., 260 to 370C., when the oils are used as lubricating oils, e.g.,

SUMMARY OF THE INVENTION Perfluoropolyether esters of quinones having the formula m 2m )n ]nQ, QI m 2m)n m 2m ,,CF(V)C0O1Q, or QI m 2m )n IQ wherein R, is a perfluoroalkyl group having from one to for aircraft turbine en ines six carbon atoms, m is an integer of from one to three, n 2 Description of g Friar A" is from 0 to about 20, R, 18 a perfluoroalkylene group F'ritz at a] in U S Pat No 3 250 807 and Moore at .havmg from two to 10 carbon atoms, V IS F or CFa, Q 18 al in U S Pat No 250 808 disclose that pera g i: radlca: ga g to 14 g gg an is e num ero y roxy groups on w 16 are fuoropolyether esters of aliphatic as well as aromatic l5 test-led and may be from one to Reg alcohols can be made by reacting a perfluoropolyether acyl fluoride with the appropriate alcohol. Moore et al.

also disclose broadly that such esters are useful as heat DESCRIPTION OF THE INVENTION transfer media and solvents. Neither reference, howf h l d ever, discloses or suggests that such esters manifest any The composmons o t 6 present mven u e utility as high-temperature stabilizers for fluorinated acyl esiers of hydroxy quinones oils. 7 said hydroxy quinones having from 10 to 14 carbon There is at the present time a recognized need for atoms from one to three groups lubricant oils which can function at temperatures Representauve of such esters are those havmg the above about 260C. for extended periods of time, e.g., mulas as turbine engine lubricants. Few oils are known, how- 0 ever, which approach serviceability under such conditions; among these are certain fluorinated oils, for ex- CFaOI F2CF(CFa) 0111c moomomoomcooample, oils prepared by fractionation of polymers which are chains of repeating units, e.g., (C,,F O)-,

which chains are suitably end-capped by very stable I end groups, for example, by hydrogen or, preferably, 0

perfluoroalkoxy or perfluoroalkyl groups.

In the absence of oxygen and certain metals, such oils can function at temperatures approaching 400 to 425C. At operating temperatures us to about 204C. CF36 Fzowmo F2O)3CFCOO even when metals are present such metals do not appear to promote degradation of the oils. However, at

temperatures between about 260 and 370C. oil 40 0 degradation has been found to occur, especially in the presence of alloys and metals such as steels, titanium o and titanium alloys and in the presence of oxygen. 1

It is therefore desireable to provide these oils with an 0 F30 F20 F20ICF(CFa) ]uC 1* a) 00 additive which eliminates or reduces oil degradation,

especially at very high temperatures. The esters of the present invention are effective stabilizers for fluorinated oil.

omcmcmocmcrncom- OC(O)(CF;)CFOCF2CF:CF:

(10(0) CF(C Fs)[OC F r-CF (C FaHoOC FgC F20 F The esters of this invention are immiscible in water. In addition to their utility as stabilizers for fluorinated oils at high temperatures, they may also be used to lubricate machine parts, e.g., gears.

Preferred because of their effectiveness as high-temperature stabilizers for fluorinated oils and their ease of preparation are monoesters of l or Z-naphthoquinone- 5,8 and diesters of l,5-anthraquinone-9,l0, wherein each ester group has the structure R;O(C,,.F O),,CF(V)COO, where R;, m, n and V are as described above. Particularly preferred within this group are the 1,5-diesters of anthraquinone-9,10 wherein each ester group has the formula CF CF CF O [CF(CF;,)CF )],,CF(C )COO, n again being from 0 to about 20. It should be noted that in preparing the esters of this invention the value of n will normally be an average value since the ester product will normally contain mixtures of ester groups which vary only in their respective n values, each n value, however, being from O to about 20. Substantially pure esters may, however, be obtained by utilizing substantially pure acyl fluoride starting materials. These substantially pure acyl fluorides may be prepared, for example, by preparative gas chromatography of, e.g., the mixtures produced by the action of ultraviolet radiation on hexafluoropropylene in the presence of oxygen, as taught in French Patent 1,434,537.

The esters of this invention may be readily prepared by contacting a selected hydroxy or polyhydroxy quinone with the perfluoropolyether acyl fluoride which is appropriate to make the desired ester. Usually the reaction is carried out in the presence of a reagent, such as pyridine or some other tertiary amine, which acts to neutralize the by-product HF. Preferably the reaction is conducted under dry conditions, i.e., in the absence of sufficient moisture to destroy important amounts of the water-reactive acyl fluoride.

Suitable equipment for the reaction would be obvious to one skilled in the art and could be constructed from materials such as glass or stainless steel or other non-corrosive materials. For large-scale production, a

glass-lined, agitable vessel having heating, colling and reflux means is quite practical, e.g., a kettle, while on a small-scale the reaction is usually carried out in such equipment as a round bottom glass laboratory flask equipped with a condenser and a thermometer.

Generally, the reaction is carried out in such a vessel by mixing together and heating in the vessel the hydroxy or polyhydroxy quinone with at least 1 mole of perfluoropolyether acyl fluoride per mol of quinone for each quinone hydroxyl group to be esterified. The specific temperature of the reaction is not critical but must be sufficient to effect the reaction between the acyl fluoride and the hydroxy quinone. Likewise, the time of the reaction while not specifically critical must be sufficient to insure substantial completion of the reaction. Typical reaction times and temperatures are from about 10to about 30 hours and from about l20C. to about 150C. for the diesters of anthraquinone and from about 10 to about 20 hours at about 40C. to about C. for the monoesters of the naphthoquinones.

The pressure employed is not critical, and ordinarily ambient atmospheric pressure is used.

The ester product can be isolated from the reaction mass by ordinary purification techniques, e.g., by vacuum stripping to remove any excess acyl fluoride followed by water washing to remove amine salt. The

60 ester material can then be dried (e.g., by vacuum bonyl group of the perfluoropolyether acyl portion of the ester having characteristic absorptions; minimiza tion of aromatic hydroxyl absorption in the spectrogram of the finished product demonstrates degree of esteriiication of the quinone.

The aryl fluorides of the present invention are selected from those having the formulas CF(V)COF, or

FC(O)CF(V)O(C,,,F ,,,),,CF(V)COF, wherein R; is a perfluoroalkyl group having from one to six carbon atoms, m is an integer of from 0 to 3, n is from 0 to about 20, R, is a perfluoroalkylene group having from two to six carbon atoms and V is F or CF The monoacyl fluorides which may be used are known in the art and can be prepared, for example by polymerizing tetrafluoroethylene oxide or hexafluoropropylene oxide either alone or in the presence of a carbonyl fluoride, a perfluoroketone or perfluoroalkanoyl fluoride as for example, in US. Pat. Nos. 3,250,806, 3,250,808 and 3,274,239. Alternatively, monoacyl fluorides can be prepared by the action of ultraviolet radiation on hexafluoropropylene in the presence of oxygen followed by treatment to reduce the peroxide content of the perfluoroacyl fluoride, as taught, for example, in Chimca e L Industria, volume 50, pp. 206 to 214 (1968).

The diacyl fluorides are also art-known and can be prepared, for example by reacting tetrafluoroethylene oxide or hexafluoropropylene oxide with the diacyl fluoride of a perfluorinated dibasic aliphatic acid having 2 to carbons, as taught, for example in US. Pat. Nos. 3,250,806 and 3,250,807. Alternatively, the diacyl fluorides may be fractionated from mixtures produced by the action of ultraviolet radiation on hexafluoropropylene in the presence of oxygen, as taught, for example in French Patent 1,434,537.

The hydroxy quinones utilized as starting materials in the present invention have from 10 to 14 carbon atoms and from one to three hydroxyl groups each. They may be prepared by any art-known process, e.g., naphthaquinone by the oxidation of e.g. 1,6- dihydroxy naphthalene; monohydroxy anthraquinone by the condensation of phenol and phthalic anhydride; dihydroxy anthraquinone by heating metahydroxy benzoic acid together with sulfuric acid; phenanthrene by the hydrolysis of the corresponding diazotized diamino compounds; and trihydroxy anthraquinone by heating the corresponding dihydroxy compound together with a concentrated alkali.

As has been stated previously, the esters of this invention are useful as additives for fluorinated oils (lubricating oils) serving to stabilize the oils and retard their degradation when said oils are used at high temperatures, e.g., above about 260C. and particularly between about 260 and 370C, e.g., as lubricating oils for turbine engines, and when the oils are in contact with metals such as steels, titanium or titanium alloys and oxygen.

The base oils to which the esters of this invention may be added are fluorinated oils preferably having the structures is a perfluoroalkylene group having from one to six carbon atoms, is the same or a different perfluoroalkylene group having from one to six carbon atoms, X is H, F or CF O, Y is Hor F and may be the same as or different from X when X is H or F, m is an integer from 1 to 3, z is an integer designating the number of (C,,.F ,,.O) groups present in the molecule wherein m is 3, p is an integer designating the number of (C,,,F ,,,O)- groups present in the molecule wherein m is l or 2 and the sum of 2+]: is an integer of from 0 to about and R"", is a 1,2-perfluoroalkylene group having from two to four carbon atoms.

Representative of the structure (a) oils are:

CF; and

CF3CF2CF2 Representative of the structure (b) oils, which are polyethers, is:

[OCF CF(CF;,)],OCF CF CF:,. Those polyethers having perfluoroalkyl end groups, i.e., without C-H bonds, are usually preferred for the additive containing oils of this invention.

The more preferred base oils within the class described above have 1. a maximum volatility of 50 percent by weight at 204.4C., as determined by Federal Test Method FIMS-791, Method 351; and

2. a maximum pour point of 10C., as determined by ASTM-D-97.

The base oils utilized in the preferred additive containing oils of this invention should have a maximum volatility of 50 percent at 204.4C. and a maximum pour point of 10C. and it may be necessary to fractionate some of the oils given above to provide them with the preferred volatility and pour point. Within this classification it has been found that the fluorinated polyether oils having molecular weights of 3,000 to 13,000 are preferable. Of course, the polymerization methods used in preparing the oils give mixtures of products so that the molecular weights are an average. Although a pure product having a specific molecular weight can be used, mixtures of products are equally useful if the variation in molecular weight is not too large. Usually, the most volatile lower molecular weight materials are removed from oils before use.

Oils having volatilities greater than 50 percent at 204.4C. while not preferred, may be utilized in preparing the greases of this invention. Oils having pour points greater than 10C., while not preferred, may also be used.

The esters are used in an effective amount in the fluorinated oils, by effective amount" is meant the amount required to produce useful inhibition of oil degradation. Thus, the effective amount of additive, i.e., ester, will vary with the service intended and with the particular metals with which the oils will come in contact.

In general the amount of an ester required will be in the range of from about 0.5 percent by weight to about 5 percent by weight based on the weight of the fluorinated base oil. Additive concentrations above about 5 percent may, of course, be employed but they may produce little increase in degradation retardation effectiveness. For a general purpose, high-temperature oil it is usually preferably to add between about 1 and about 5 percent by weight of the esters. This range provides for the vast majority of the needs for the oils.

Preparation of the perfluorinated polyether oils containing the esters is by mixing of the two components in the indicated proportions for a time and at a temperature sufficient to assure solubility of the ester in the fluorinated oil. The lower molecular weight esters, for example, where n is from to about 4 are best mixed with the oils at about 100C. to assure complete solubility. The solubility of the esters wherein n is greater than about 5 is usually essentially complete at between 25 and 100C., while the esters with n equal to to 20 are usually completely soluble at room temperature, i.e., at about 20 to 25C.

Fluorinated oils stabilized with the esters of the invention have practical advantages over such oils unstabilized. For example, at the high temperatures met in modern aircraft turbine engines where such oils, when used as lubricants, contact steel and titanium alloy components, the stabilized oils resist viscosity degradation and the closely associated volatilization of the lubricant oil. Lubricant loss is minimized. Periods between oil replacement are extended. Higher operating temperatures may be employed and engine heat efficiency thereby improved.

EXAMPLES The following examples are intended to be merely illustrative of the invention and not in limitation thereof. Unless otherwise indicated, all quantities are by weight.

EXAMPLE 1 A mixture of 24 parts (0.1 mole) of 1,5-dihydroxyanthraquinone 170 parts (0.3 mole) of CF CF CF OCF(CF )CF2OCF(CF )COF and 18 parts of pyridine (0.2 mole) were refluxed for 16 hours at about 120 to 140C. in a round bottom glass laboratory flask equipped with a condenser and a thermometer. The resulting reaction mass was then subjected to a water pump vacuum stripping at l C. until substantially all distillation stopped. The stripped mixture was suspended in about 400 parts of trichlorotrifluoroethane. The suspension was washed with 5 percent aqueous NaHCo and with 5 percent aqueous hydrochloric acid. After drying the resultant trichlorotrifluoroethane solution over anhydrous M,- SO the solution was freed of most of the solvent by vacuum stripping at C. A semi-solid product resulted. An 8 part portion by weight of the semi-solid was heated for about 16 hours at C. to complete the solvent evaporation.

The resulting semi-solid, 6 parts by weight, was shown by infrared analysis to be substantially free of aromatic hydroxyl groups and to have the ester carbonyl absorption expected for the 1,5-dihydroxyanthraquinone diester.

The diester was found to be miscible up to about 10 percent by weight in a perfluorinated polyether oil having the formula CF CF CF O]CF(CF )CF O],CF CF wherein z had an average value of about 32 and the oil having an average molecular weight of 5,800.

EXAMPLE 2 A mixture of 10 parts (0.04 mole) of 1,5-dihydroxyanthraquinone, 190 parts (0.1 mole) of CF CF CF O[CF(CF )CF O1nCF(CF )COF where n had an average value of 10, and 8 parts (0.1 mole) of pyridine was heated at C. for 16 hours. The reaction mixture was then suspended in 200 parts of trichlorotrifluoroethane and the suspension was washed with distilled water. The

EXAMPLES 3 and 4 The same process as in Example 2 was used to prepare homologous 1,5-diesters of anthraquinone wherein n averaged 4 to 8 except that the corresponding acyl fluoride homologes were utilized in place of CF CFzCF O[CF(CF3)CF2O]nCF(CFa)COF wherein n averaged 10. The products were both oils at room temperature and miscible in all properties in the perfluoropolyether oil of Example 1 at 100C.

EXAMPLE 5 A suspension of 100 parts (0.04 mole) of the acyl fluoride CF CF CF O[CF(CF )CF O],,CF(CF )COF, n averaging 14, 7 parts (0.04 mole) of 2-hydroxynaphthoquinone and 10 parts of pyridine in 80 parts of trichlorotrifluoroethane were refluxed for 16 hours. The resulting reaction mass was washed with water forming a trichlorotrifluoroethane solution and an aqueous layer. The heavier trichlorotrifluoroethane solution then separated from the less dense aqueous layer. The trichlorotrifluoroethane solution was dried over anhydrous M,SO treated with decolorizing charcoal and filtered. Upon removal of the trichlorotrifluoroethane, an oil was recovered. Infrared analysis showed that the oil had the structure of the 2- ester of naphthoquinone. It was found to be miscible at 5 weight percent and at 25C. in the perfluoropolyether oil of Example 1.

is reflected in a prolonged useful life for an oil in actual use, e.g., as a turbine engine lubricant.

EXAMPLES 6 to 15 The compositions of this invention were tested using a modified form of the apparatus specified in the WADD Microoxidation-Corrosion Test of High Temperature Fluids, Fluids and Greases Section, Aeronautical Systems, Wright-Patterson Air Force Base, replacing the specified Pyrex tube with an Inconel tube. Basically the apparatus consists of a 3.18 mm diameter Inconel tube adapted for mounting three washers outside the lower end. The 3.18 mm tube is inserted inside a 20.6 mm diameter vertical Inconel tube so that the washers are immersed in a body of oil contained in the larger tube. The larger tube, which is adapted with a condenser for recovering any oil which may be stripped from the tube, is inserted in an aluminum heating block.

Various metal washers of the compositions in Table l were tested.

TABLE 1 Metal in Washers Compositions, by weight Group A (Steels) The tests consisted of placing test washers of the metals to be tested in the apparatus, adding sufficient of the oil composition to insure that the washers were covered, assembling the remaining apparatus and inserting it in the heating block. The oil was then heated to the test temperature and air was passed down through the smaller tube into the body of oil containing the washers. Test duration was 72 hours. Dry air flow rate into the oil during the test was liters per hour, measured at 25C.

Degradation in the test oils was evaluated by determining percent change in the viscosity of the test oil during the test. The results are expressed in Table [1 below as:

cs. after test: cs. l fo gt st 100 where cs is the kinematic viscosity, at 38C., in centistrokes. When the sign of the percent viscosity change is negative, oil degradation is indicated. When the sign is positive, high temperature loss of volatile oil components is indicated. It will be noted in Table 11 that oil degradation was normally accompanied by increased fluid loss from the apparatus. Degradation of polymer chains provides fragments having greater volatility than the original polymer. The base oil used in the following examples had the formula CF CF CF O[CF(CF )CF Olzz CF CF wherein z had an average value of about 28 and the base oil had an average molecular weight of about 5,000.

TABLE II 72 Hours fluid loss and Viscosity Change 315C. 343C. Source of Ester Tablel %fluid Example Example Washer wt.% %vis. loss vis. No. No. Metals addiflu change loss change tive -id loss 6 none none 2.2 0.02 6.2 9.2 7 1 2.4 0.58 +6.3 8 3 Group 1.01.17 +3.4 2.4 +0.8

(Steels) 1.0 0.83 +4.6 1.9 +1.3 10 2 'l.3 1.0 0 6.1 -9.2 11 none none 12.2-50.2 79.7 99.0 12 l 1.0 2.3 +9.3 l3 3 Group 1.0 2.5 +10.6 62.3 92.6 14 4 B .(Tiand 1.0 5.3 7.2 28.6 77.8 15 2 its Alloys) 1.3 2.5 +2.9 55.2 93.2

EXAMPLE 16 The test procedure and a base oil as in Examples 6 to Example 5 at 335C. a Ti and a Ti (6A1 4V) washer was used in the test. Without additive a -84 percent viscosity change occurred; with 5 percent of the ester the change was only 5.4 percent.

EXAMPLE 17 A suspension of 17 parts (0.1 mole) of 2-hydroxy- 5,8-naphthoquinone, 35 parts (0.025 mole) of [FOCCF(CF3)[OCF CF(CF )],.OCF2+2 wherein n had an average value of 3, which is prepared from oxalyl fluoride and hexafluoropropylene oxide by the process of Example 111 of U.S. Pat. No. 3,250,807, 200 parts of trichlorotrifluoroethane and 2 parts of pyridine are refluxed for 17 hours. The resulting suspension is filtered and the clear filtrate is washed about 7 times with 200 parts portions 5 percent aqueous potassium carbonate and then twice with the same quantity of distilled water. The trichlorotrifluoroethane solution is freed of solvent by vacuum stripping at C. at 40 mm Hg absolute pressure. Infrared analysis indicates that the resulting ester product has the expected structure, i.e.,

The results of Examples 6 to 17 clearly show the effectiveness of the esters of this invention in reducing the high-temperature degradation of fluorinated lubricant oils. It will be appreciated that even a modest increase in oil stability as indicated by this accelerated test can mean a significant increase in oil life under high-temperature use conditions. A significant commercial advantage is, thereby, provided in terms of longer life for relatively expensive oils.

The foregoing detailed description has been given for clarity of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to exact details shown and described for obvious modifications will occur to one skilled in the art. Similar results of prolongation and stabilization of the useful life of fluorinated oils can be effected by adding other esters with the scope of this invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. Perfluoropolyether esters of quinones having the formula wherein R, is a perfluoroalkyl group having from one to six carbon atoms, m is 2 or 3, n is from to about 20, R, is a perfluoroalkylene group having from two to carbon atoms, V is F or CF Q is a quinone radical having from 10 to 14 carbon atoms and p is the number of hydroxyl groups on O which are esterified and may be from 1 to 3.

2. Perfluoropolyether esters of quinones according to claim 1 having the formula wherein R, is a perfluoroalkyl group having from one to six carbon atoms, m is 2 or 3, n is from 0 to about 20, R, is perfluoroalkylene group having from 2 to lo carbon atoms, V is F or CF;,, Q is a quinone radical having from 10 to 14 carbon atoms and p is the number of hydroxyl groups on Q which are esterified and may be from 1 to 3.

3. Perfluoropolyether esters of quinones according to claim 1 having the formula wherein R, is a perfluoroalkyl group having from one to six carbon atoms, m is 2 or 3, n is from 0 to about 20, R; is a perfluoroalkylene group having from two to 10 carbon atoms, V is F or CE, and Q is a quinone radical having from 10 to 14 carbon atoms.

4. Perfluoropolyether esters of quinones according to claim 3 having the formula wherein R, is a perfluoroalkyl group having from one to six carbon atoms, m is 2 or 3, n is from 0 to about 20, R, is a perfluoroalkylene group having from two to 10 carbon atoms, V is F or CF; and Q is a quinone radical having from 10 to 14 carbon atoms.

5. Perfluoropolyether esters of quinones according to claim 2 having the formula 0 wherein R, is a perfluoroalkyl group having from one to six carbon atoms, m is 2 or 3, n is from O to about 20 an V is F or CF 6. Perfluoropolyether esters of quinones according to claim 2 having the formula wherein R; is aperfluoroalltyl group hazing from one to six carbon atoms, m is 2 or 3, n is from 0 to about 20 and V is F or CF 7. Perfluoropolyether esters of quinones according to claim 2 having the formula .Rmwanmmnomwoot) U V V wherein R, is a perfluoroalkyl group havingfrom one to six carbon atoms, m is 2 or 3, n is from 0 to about 20 and V is F or CF;,.

8. Perfluoropolyether esters of quinones according to claim 7 wherein the ester groups have the formula CF CF CFB2O[CF(CF )CF O] O],,CF(CF )COO wherein n is from 0 to about 20.

9. Perfluoropolyether esters of quinones according to claim 8 wherein n averages 14.

10. Perfluoropolyether esters of quinones according to claim 8 wherein n averages 10.

3;;3 :UNITED STATES IQ-LATENT' OFFiCE' CERTIFICATE OF, CORRECTION Inventor s BRUCE HOLLIS GARTH f It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 12, line 46, Claim 8, the formula should read I Signed and sealed this 1st da of May 1973.

(SEAL) fafitest; I

EDWARD M. FLETCHER, JR. ROBERT GOTTSCHAIK Attesting Officer" I Commissioner of Patents

Claims

2. Perfluoropolyether esters of quinones according to claim 1 having the formula (RfO(CmF2mO)nCF(V)COO)pQ wherein Rf is a perfluoroalkyl group having from one to six carbon atoms, m iS 2 or 3, n is from 0 to about 20, R''f is perfluoroalkylene group having from 2 to 10 carbon atoms, V is F or CF3, Q is a quinone radical having from 10 to 14 carbon atoms and p is the number of hydroxyl groups on Q which are esterified and may be from 1 to 3.
3. Perfluoropolyether esters of quinones according to claim 1 having the formula Q(OC(O)CF(V)(OCmF2m)nOR''fO(CmF2mO)nCF(V)COO)Q wherein Rf is a perfluoroalkyl group having from one to six carbon atoms, m is 2 or 3, n is from 0 to about 20, R''f is a perfluoroalkylene group having from two to 10 carbon atoms, V is F or CF3 and Q is a quinone radical having from 10 to 14 carbon atoms.
4. Perfluoropolyether esters of quinones according to claim 3 having the formula Q(OC(O)CF(V)O(CmF2mO)nCF(V)COO)Q wherein Rf is a perfluoroalkyl group having from one to six carbon atoms, m is 2 or 3, n is from 0 to about 20, R''f is a perfluoroalkylene group having from two to 10 carbon atoms, V is F or CF3 and Q is a quinone radical having from 10 to 14 carbon atoms.
5. Perfluoropolyether esters of quinones according to claim 2 having the formula
6. Perfluoropolyether esters of quinones according to claim 2 having the formula
7. Perfluoropolyether esters of quinones according to claim 2 having the formula
8. Perfluoropolyether esters of quinones according to claim 7 wherein the ester groups have the formula CF3CF2CF2O(CF(CF3)CF2O)2O)n-CF(CF3)COO- wherein n is from 0 to about 20.
9. Perfluoropolyether esters of quinones according to claim 8 wherein n averages 14.
10. Perfluoropolyether esters of quinones according to claim 8 wherein n averages 10.