US3483129A - Perfluorinated substituted phenyl phosphine lubricant additives - Google Patents

Description

United States Patent Office 3,483,129

Patented Dec. 9, 1969 3,483,129 OBJECTS PERFLUORINATED SUBSTITUTED PHENYL PHOSPHINE LUBRICANT ADDITIVES It 15 therefore an ob ect of th s mvention to prov1de new and useful compositions of matter.

2 1 1 5 s igbgfi fgg zi gg g ggagfi 5: 2 :21: It is a further object to permit more latitude in the signers to the United states of America as repre 5 choice of metals for future aerospace systems for opera- Sented by the Secretary f the Air Force tron at 650 F. in the presence of a lubricant.

No Drawing. Filed Feb. 13, 1968, Ser. No. 705,025 It s a further object to provide compositions which Int. Cl. Cm 1/30 can withstand severe oxidative stress at temperatures of US. Cl. 25249.9 20 Claims 650 F. without appreciable degradation. 10 It is a further object of the invention to provide such compositions for use as lubricants, hydraulic fluids and ABSTRACT OF THE DISCLOSURE the like, for contact with metal bearings and other metal Perfluorinated substituted phosphines; for example, trissurfaces in gas turbine engines d in asmspace systems [4-(pentafluorophenoxy)tetrafiuorophenyl] phosphine and at temperatures in some Cases as high as tris(4-heptafluorotolyl) phosphine are used as additives It is a specific Object of the invention to Provide to perfluorinated aliphatic polyethers. A minor percent- Positions Comprising a perfluorinated aliphatic Polyether age, up to 5 percent but preferably 0.010.2 percent, of and substituted perfluorinated phenyl phosphinesthe additives are used. The resulting compositions are DESCRIPTION OF THE INVENTION useful as lubricants and hydraulic fluids at temperatures as hi h as 650 We have now found that the foregoing and related ob ects can 'be attained m a composition comprising a perfluorinated aliphatic ether and a minor proportion of The invention described herein may be manufactured a perfluorinated phenoxyphenyl phosphine having the and used by or for the United States Government for govstructure: ernmental purposes without payment to use of any royalty (@T BACKGROUND Particularly useful compositions comprise, as the phosphine, tris[4-(pentafluorophenoxy)terafluorophenyl]phosphine; and comprise as the ether, base fluid I or base fluid II.

The perfluorinated phenoxyphenyl phosphine additive It has been taught in the art that prefluorinated aliphatic polyethers are useful as lubricants at high temperatures. Among the compounds which can be used are, for example, compounds of the general formula:

is preferably used in proportions of about 0.0l0.2 per- F CF Q- CF QF O.- CF X cent by weight partly for the reason that optimum per- /n formance is attained and partly for the reason that the where n is a positive integer including zero a d X i a additive is more readily dissolved in the base fluid. Trismember of the class consisting of fluorine and the per- (pentafiuorophenoxy)tetrafluoropenyllphosphine is fluororneth l radical, The preparation of th s compounds soluble in the base fluids at room temperature at concen- (hereinafter referred to as base fluid I) is disclosed by 40 a ns f a out 0.02 weight percent or less. Between Miller in US. Patent No. 3,242,218. Also among the 0.02 an -2 weight percent, the phosphine is not soluble compounds which are particularly useful are compounds at room temperature but is soluble at elevated temperof the type (hereinafter referred to as base fluid II): atures. However, concentrations above 0.2 weight perls /m where n and m are integers greater than 2. The preparacent, and up to about 5 percent, are not believed to be tion of these latter compounds is disclosed by Milian in detrimental and can be used if additive solubility is not US. Patent No. 3,214,478. required at room temperature. It is recommended that at Developments in aerospace technology have placed a least 0.1 percent additive be used for operations at severe demand on lubricants, particularly where the lubri- 650 F. cants are to function in oxidizing atmospheres and at tem- The compositions can be prepared by adding the deperatures up to 650 F. Such conditions test not only sired proportion of the additive to the base fluid and heatthe oxidative stability of the lubricant but also its high ing with agitation until the composition is homogeneous temperature stability in the presence of metals such as and solution has taken place. steel, titanium and the like. The above described per- Another example of a substituted perfluorinated phenyl fluorinated aliphatic polyethers, without additives, have phosphine that can be used is, tris(4-heptafluorotolyl) failed under such exacting conditions. Specifically, such phosphine. polyethers corrode ferrous and titanium alloys above Tris(4-heptafluorotolyl)phosphine, having the structure 500 F. to a significant degree.

In our copending application (Ser. No. 581,419 filed (CFQLP Sept. 21, 1966, now US. Patent 3,393,151 dated July 3 we suggestfid the W f lub11a11tconlposifiol'ls is highly effective in reducing corrosion of ferrous and comPnsmg a perfllfonnated ahphatlc Polyethel' 3 titanium alloys in the perfluorinated aliphatic polyether Pound such as (p l p l y )P p fluids and inhibits the degradation of the fluids them- (pelltaflllofophenyl)Phosphlne OXlde- We found that the selves. This new additive is effective in concentrations as latter Compositions Were highly effective ill reducing low as 0.10 wt. percent and optimum concentrations aprosion and fluid degradation at temperatures of 550-600 pear t be near 0,25 wt percent, h optimum concentra- F., but their usefulness is somewhat limited by their volations of previous perfluoroarylphosphine additives, set tility at these and, particularly, higher temperatures. forth in patent application Ser. No. 581,419, filed Sept. 21,

1966, were as high as 0.5 to 1.0 wt. percent. Thus optimum effectiveness of tris(4-heptafluorotolyl)phosphine is obtained at lower concentrations than with former additives as evidenced in 600 F. oxidation-corrosion tests.

Tris(4-heptafluorotolyl)phosphine is soluble in the perfluorinated aliphatic polyether fluids in 0.25 wt. percent for several days at room temperature. Concentrations of the additive less than 0.25 wt. percent remain soluble for longer periods of time below room temperature. Concentrations of the additive as high as wt. percent are not believed to be seriously detrimental and can be used if additive solubility is not required at room temperature.

EXAMPLE 1 Compositions consisting of base fluid I with 0.05 and 0.20 percent tris[4-(pentafluorophenoxy)tetrafluorophenyl]phosphine were formulated and compared with base fluid I with no additives in an oxidation-corrosion test in contact with various metal washers. The test procedure involves the total immersion of the metal specimen in the test composition and, for a period of 24 hours, the bubbling of one liter per hour of dry air through the composition and over the metal specimens at a temperature of 600 F. The weight change (mg. per cm?) of the metal washers is used as the measure of corrosion. The metal specimens chosen represent a variety of ferrous alloys likely to be encountered in the commercial use of the compositions of the invention. Results are shown in Table 1, weight changes of less than 0.10 mg. per cm. being considered negligible and weight changes less than 0.20 mg. per cm. being minor.

EXAMPLE 2 The test procedure of Example 1 was carried out using 0.05 percent of the additive with base fluid II. Results are shown in Table 2.

EXAMPLE 3 The test procedure of Example 1 was carried out using 0.01, 0.02, 0.05, and 0.1 percent of the additive with base fluid I. The metal specimens used included commercially pure titanium and two titanium alloys likely to be encountered in the commercial use of the compositions of the invention. Fluid evaporation losses and percent viscosity changes during the experiment were also measured. Results are shown in Table 3.

EXAMPLE 4 The test procedure of Example 1 was carried out using 0.05 and 0.10 percent of the additive with base fluid II and the various titanium specimens. Results are shown in Table 4.

EXAMPLE 5 The test procedure of Example 1 was carried out using 0.10 and 0.20 percent of the additive with base fluid I. The composition was maintained at a temperature of 650 F., at which temperature kinematic viscosity changes hecame significant. Results are shown in Table 5.

EXAMPLE 6 Composition of base fluid II and 0.25 wt percent tris (4-heptafluorotolyl)phosphine was formulated and compared with base fluid II without an additive at 600 F. according to the test procedure of Example 1 using varous ferrous alloys. Results are shown in Table 7.

EXAMPLE 8 Compositions consisting of base fiuid I and 0.25 and 0.50 wt. percent tris(4-heptafluorotolyl)phosphine were formulated and compared with the uninhibited base fluid I at 600 F. according to the test procedure of Example 1 using commercially pure titanium and two titanium alloys. Results are shown in Table 8.

The previous examples were repeated using various proportions of the phosphine additives to base fluid I and to base fluid II. Additive additions of about 0.01-0.2 percent performed best for overall use, with proportions above about 0.2 percent being best for use at 650 F. Concentrations of up to 5 percent were useful.

The compositions are useful as completely non-flammable hydraulic fluids in the temperature range of about 20 to +700 F., as gas turbine engine lubricants in the range of about 0 F. to 650 F., in greases to be used at 30 F. to 600 F., and as liquid coolants and general purpose lubricants up to 650 F.

It is to be understood that the foregoing examples and description are for the purpose of illustration only, and that various changes may be made therein without departing from the spirit and scope of the invention.

TABLE 1 Weight change in mg. per cru.

52100 M-2 M- 440C Wt. percent (CgFbOCtFOtP 4140 Bearing Tool Tool 410 Stain- Stainless additive Steel steel steel steel less steel steel TABLE 2 Weight change in mg. per cm.

52100 M-2 M-50 440C Wt. percent (CaF50CoF4)aP 4140 Bearing T001 T001 410 Staln- Stainless additive Steel steel steel steel less steel steel TABLE 3 Weight change in mg. per cm. Kinematic Fluid viscosity Titanium Tit anium Titanium Wt. percent evap. change (commera 0y allo (CaFsOCqFOgP loss, at 100 F., cially (4% Al, (6% Al additive percent percent pure) 4% Mn) 4% V5 TABLE 4 Weight change in mg. per cm. Kinematic Fluid viscosity Titanium Titanium Titanium Wt. percent even. change (commeralloy alloy (CiFtOCtFmP loss, at 100 F., cially (4% Al, (6% Al, additive percent percent pure) 4% Mn) 4% V) TABLE 5 Weight change in mg. per cm.

Kinematic Fluid viscosity Titanium Titanium Titanium Wt. percent evap. change (commeralloy alloy (ctF50CoF4)3P loss, at 100 F., cially (4% Al, (6% Al, additive percent percent pure) 4% Mn) 4% V) None 50. 0 --91. s -0. 60 -2. e0 1 +0.01 0.1- 2. 3 +1. 4 +0.13 +0. 07 2 +0. 09 0.2-.. 0. 2 +1.8 +0.08 +0. 12 3 +0. 06

1 Gray-black surface. 2 Blue-violet discoloration with slight graying. Blue-violet discoloration; no graying.

TABLE 6 Weight change in mg. per cm.

52100 M-2 M-50 ,4400 Wt. percent (CFaCoF4)aP 4140 Bearing T001 T001 410 Stain- Stainless additive Steel steel steel steel less steel steel TAB LE 7 Weight change in mg. per em.

52100 M-2 M- 440C Wt. percent (CF3CUF4)3P 4140 Bearing Tool Tool 410 Stain- Stainless additive Steel steel steel steel less steel steel TABLE 8 Weight change in mg. per cm. Kinematic Fluid viscosity Titanium Titanium Titanium Wt. percent evap. change (commeralloy alloy (CFsCaF4)aP loss, at 100 F., cially (4% Al, (6% Al, additive percent percent pure) 4% 4% V) We claim: where n is a positive integer including zero and X is 1. A composition suitable for use as a lubricant at a member of the group consisting of fluorine and the high temperatures, said composition comprising a major 50 perfluoromcthyl radical. amount of a perfiuorinated aliphatic polyether and a 8. The composition according to claim 1 wherein said minor stabilizing proportion of a perfiuorinated phenoxyphosphine is tris[4-(pentafluorophenoxy)tetrafluorophenphenyl phosphine. ylJphosphine and said ether has the formula;

2. The composition according to claim 1 wherein said X phqsphine is tris[4-(pentafluorophenoxy)tetrafluorophen- I 3. The composition according to claim 1 wherein said proportion is about 0 01 5 percent b weight of the o where n is an integer including zero and X is a member of position. the group consisting of fluorine and the perfluoromethyl '4. The composition according to claim 1 wherein said al. proportion is about 0.0l-0.2 percent by weight of the 9. The composition according to claim 1 wherein said composition, phosphine is tris[4-(pentafluorophenoxy)tetrafluorophen- 5. The composition according to claim 2 wherein the y lp p and Said ether has e formula:

where n and m are integers greater than 2.

10. The composition according to claim 9 wherein the proportion of said phosphine is about 0.015 percent by phosphine is present in a proportion of about 0.01-5 percent by weight of the composition.

6. The composition according to claim 2 wherein the phosphine is present in a proportion of about 0.0l-0.2 Weig of the compositionpel-cent by weight f the composition. 11. A composition suitable for use as a lubricant at 7. The composition according to claim 1 wherein said high temperatures, d composition comprising a major ether has the fo l proportion of a perfluorinated aliphatic polyether and a minor stabilizing proportion of a perfluorinated tolyl f phosphine. XCF CF OYCFCF O/ CFQX 12. The composition according to claim 1 wherein said phosphine is tris(4-heptafluorotolyl)phosphine.

13. The composition according to claim 11 wherein said proportion is about 0.10- percent by Weight of the composition.

14. The composition according to claim 11 wherein said proportion is about 0.25 percent by weight of the composition.

15. The composition according to claim 12 wherein wherein n is an integer including zero and X is a member of the group consisting of fluorine and the perfiuoromethyl radical.

19. The composition according to claim 11 wherein said phosphine is tris(4-heptafluorotolyl)phosphine and said ether has the formula:

the phosphine is present in a proportion of about 0.10-5 percent by weight of the composition.

16. The composition according to claim 12 wherein the phosphine is present in a proportion of about 0.25 percent by weight of the composition.

17. The composition according to claim 11 wherein said ether has the formula:

CFZX lu where n and m are integers greater than 2 20. A composition according to claim 19 wherein the proportion of said phosphine is about 0.10-5 percent by weight of composition.

References Cited UNITED STATES PATENTS 3,115,466 12/1963 Orlofi et a1 25249.9 3,214,478 10/1965 Milian 260615 3,367,870 2/1968 Spivack 25249.8 3,393,151 7/1968 Dolle et a1 25249.9 2,888,481 5/1959 Wilson 25249.9 X

DANIEL E. WYMAN, Primary Examiner W. CANNON, Assistant Examiner US. Cl. X.R. 25254, 78, 400