CA2102739C

CA2102739C - Phosphazene derivatives and use of same as stabilizers for oils and greases based on perfluoropolyethers

Info

Publication number: CA2102739C
Application number: CA002102739A
Authority: CA
Inventors: Paolo Odello; Walter Navarrini; Richard D. Chambers; Costante Corti
Original assignee: Ausimont SpA
Current assignee: Solvay Specialty Polymers Italy SpA
Priority date: 1992-11-10
Filing date: 1993-11-09
Publication date: 1999-04-13
Anticipated expiration: 2013-11-09
Also published as: KR100292024B1; JP3558667B2; JPH06220077A; DE69321069D1; US5441655A; ITMI922569A0; US5705668A; ATE171183T1; US5602270A; EP0597369B1; ITMI922569A1; EP0597369A1; IT1256304B; KR940011471A; DK0597369T3; DE69321069T2; CA2102739A1

Abstract

New phosphazene derivatives, fully substituted by aromatic groups and perfluoropolyethereal chains, are utilized as stabilizers for oils and greases based on perfluoropolyethers.
Such derivatives inhibit the degradation process affecting the perfluoropolyethereal chains when these are subjected to high temperatures in an oxidizing atmosphere and in the presence of metals, such as for example aluminium, titanium, vanadium and their alloys, or steels.

Description

211)27~g TITLE

"NEW PHOSPHAZENE DERIVATIVES AND USE OF SAME AS STABILIZERS FOR
OILS AND GREASES BASED ON PERFLUOROPOL~ KS"

AUSIMONT S.p.A.

(EST/EP'~

- 2 - 2~ ~ 7~g A~ 5117 * * * * * *

The present invention relates to new phosphazene der-ivatives and to the use of same as stabilizers for oils and greases based on perfluoropolyethers.
It is known to use fluid perfluoropolyethers as lu-bricating oils characterized by high performances under ex-tremely severe temperature and load conditions and endowed with an excellent resistance to atmospheric agents and chemic-al agents in general, as well as to high temperatures. Per-fluoropolyether-based greases prepared'by addition of a proper thickening agent to the perfluoropolyethereal fluid are known too (see for example Italian patent IT 963,579 or patent ap-plication EP 95,825).
A drawback connected with the use of perfluoropoly-ethers as lubricants is due to the degradation process which the perfluoropolyethereal chains undergo when they are sub-jected to high temperatures (generally starting from 200-300~C) in an oxidizing atmosphere and in the presence of me-tals, such as e.g. aluminium, titanium, vanadium or their al-loys, or steels. Such process causes a decay of the lubricat-ing properties, besides a progressive corrosion of the same (EST/EP) ~ ~... .
metals.
In order to obviate the abovesaid drawback it is known to add little amounts of stabilizing additives to the oils or greases based on perfluoropolyethers. for example, U.S. patent 4,454,349 describes the use, as stabilizers, of arylphosphines of general formula:

RfORfCF2 ~
_3 where RfROf is a perfluoropolyethereal group. Such products are obtainable only through an utmostly complex multistep pro-cess, which is fully unsuited to an industrial-scale applic-ation. In fact, such process comprises, among the various steps, the fluorination of the substrate with SF4 and HF, this being a reaction which raises a lot of problems concerning the plant engineering (low reaction rate, high temperatures and pres-sures, dangerousness of the reagents, difficult separation of the final products, etc.).
Further arylphosphinic products suitable for being utilized as stabilizers for oils and greases based on per-fluoropolyethers are the ones described in U.S. patent 4,681,693.
Such products have a structure analogous with the one of the arylphosphines described in the above-cited U.S.patent 4,454,349, in which however the perfluoropolyethereal chains are linked to the aromatic ring by means of non-fluorinated groups of (ESTIE"

2I02?~9 _ - 4 -various nature. This structural modification permits to simp1ify the preparatiOn process (in particular, the abovesaid fluorin-ation reaction with SF4 and HF is no longer required), what, how-ever, does not reduce the effectiveness of such products as stabilizers. In spite of this considerable simplification, an in-dustrial-scale production of arylolefins is still complicate and expensive, in consideration of the fact that several intermedi-ate steps are required before the final product can be obtained.
Phosphazenes are products well known in the art. They are characterized by the presence of the -N=P- group, which is the basic unit for the formation of both cyclic and linear structures.
For example, U.S. patents 5,015,405 and 5,099,055 described cyclic phosphazene derivatives of formula:
(lRJ2 -(-N=P-) -where n ranges from 3 to 7, while substituents R are fluorinat-ed phenoxy groups or 3-perfluoroalkyl-phenoxy groups, on cond-ition that the ratio of phenoxy groups to 3-perfluoroalkyl--phenoxy groups ranges from 1:5 to 1:1.
Such phosphazene derivatives are per se utilizable as lubricants for high temperatures, or as additives for other lubricants. In particular it is to be pointed out the possibi-lity~of uti1izing these products as antiwear additives for conventional oils, such as polyglycols, polyphenylethers and (EST/EP) ~ CA 02102739 1998-07-31 ' polyol esters (see also the article by B.S. Nader, K.K. Kar, T.A.
Morgan, C.E. Powloski and W.L. Dilling, published in "Tribology Transactions ", 35, 37 ( 1 992)) .
The Applicant has now found a new class of phosphazene derivatives, which are endowed with excellent stabilizing properties for oils and greases based on perfluoropolyethers and are preparable according to a relatively economic process, which can be easily practised also on an industrial scale.
Thus, a first object of the present invention are the phosphazene derivatives of cyclic or linear structure, having formula:
(1)2 [(A)4p]n-(-N = P~)m~(A)n (I) where:
n is O in the case of a cyclic structure, n is 1 in the case of a linear structure;
m is an integer from 3 to 7;
groups A, like or different from one another, are selected from:
(i) R-Q-, in which Q is a divalent group selected from:
-O-, -S-, -NR,- (in which R, is hydrogen or a C,-C4 alkyl), and -NH-NH-; R is a C6-C,2 aryl group, preferably a phenyl, optionally substituted by one or more, preferably 1 or 2 groups selected from:
C1-C4 alkyls, -OR2, -NR3R4, -NO2, -F and -Cl, where R2, R3 and R4 are hydrogen or C1-C4 alkyls;

~,f~

_ - 6 -(ii) Rf-CH20(CH2CH20)S-, wherein: s = 0, 1 or 2; Rf is a per_ fluoropolyethereal chain having a molecular weight ranging from 400 to 10,000, preferably from 400 to 4,000, and co~-posed of repeating units selected from:

(a) (Cf-CF20) and (CFX0), where X is -F or -CF3;

(b) (Cf2CF20) and (CF20);

(c) (If-cF2o)~ (CF2CF20) and (CFX0), where X is -F or -CF3;
(d) (CIF-CF20);

3 ,, (e) (CYZ-CF2CF20), where Y and Z, like or different from each other, are F, Cl or H;
(f) (CF2CF20);
the various repeating units being statistically distrib-uted along the chain;

with the proviso that at least a group of type (i) and at least a group of type (ii) are present in the same moleculei groups R-Q- being also capable of forming, if linked to the same P atom, a cyclic structure of type :
R

Q / Q

-N - P /
A further object of the present invention are (EST/EP) ~ - 7 - 2102739 the 1ubricating compositions comprising:
(a) an oil and a grease based on perfluoropolyethers;
(b) from 0.05 to 3~ by weight, preferably from 0.5 to 1% by weight, of a phosphazene derivative of formula (I).
The phosphazene derivatives forming the object of the present invention are in the form of viscous, transparent and colorless f1uids, which are fully sol~ble and easily sol-ubilizable, at the above indicated concentrations, in the perfluoropolyether-based lubricants, and exhibit an excel-lent thermal stability also at temperatures higher than 300~C.
Among the phosphazene derivatives of formula (I), the preferred ones are those exhibiting a cyclic structure (n=0), having a molar ratio between Rf-CH20(CH2CH20)S- groups and R-Q- groups ranging from about 0.2 to about 1.8, prefer-ably from about 0.5 to about 1. Within such subclass, the ones in which m is 3 or 4 are particularly preferred.
The perfluoropolyethereal chains Rf can be select-ed in particular from the following classes:
(a) T-O- (CFCF20) m (CFXO) n-CFZ- ( I I ) where:
T is a ~per)fluoroalkyl group selected from:

-CF3, -C2Fs, -C3F7, -CF2Cl, -C2F4Cl, -C3F6cll X is -F or -CF3;
Z is -F~ -Cl or -Cf3; m and n are numbers such that the ntm ratio ranges from 0.01 to ~.5 and the molecular (EST/EP~

~ 8 - 2102739 weight is in the above-indicated range;
(b) Tl-O-(CF2CF20)p(CF20)q-CFzl- (III) where:
T is a (per)fluoroalkyl group selected from:
-CF3, -C2F5, -CF2Cl, -C2F4Cl; zI jS -F or -Cl; p and q are numbers such that the q/p ratio ranges from 0.5 to 2 and the molecular weight is in the above indicated range;
( C ) Tn-O- (CFCF20) r~ (CF2CF20) ~- (CEXnO) ,-CFZn- ( IV) where:
T is a (per)fluoroalkyl group selected from:

3 2 5 3F7, CF2Cl, -C2F4Cl, -C F Cl; XII i -f or -CF3; Z is -F, -Cl or -ÇF3; s and t are num-bers such that r + s ranges from 1 to 50, the t/(r+s) ratio ranges from 0.01 to 0.05 and the molecular weight is in the above indicated range;

(d) Tm-O-(CFCF20)u-CF- (V) where:
T is -C2F5 or -C3F7; u is a number such that the molecular weight is in the above indicated range;

(e) TlV-O- ( CYZ - CF2CF20 ) V - CYZ - CF2 - ( V I ) where:
Y and Z, like or different from each other, are F, (EST/EP) Cl or H; T is -CF3, -C2F5 or -C3F7; v is a number such that the molecular weight is in the above indicated range;

(f) T ~ ( 2 2 w 2 (VII) where:
T is -CF3 or -C2F5; w is a number such that the mol-ecular weight is in the above indicated range.
The hydroxy-terminated perfluoropolyethers Rf-cH2o(cH2cH2o)sH are product known in the art. They are pre-parable by reduction of the -COF end groups contained in the starting perfluoropolYetherS~ according to what is described for example in U.S. patents 3,847,978, 3,810,874 and 4,814,372. The starting perfluoropolyethers containing -COF
end groups are described, for example, in patents GB l,104,~2 (class (a)), US 3,715,378 (class (b)), US 3,242,218 (class (c)), US 3,242,218 (class (d)), EP 148,482 (class (e)), US
4,523,039 (class (f)), or also in patent application EP 340,740.
The phosphazene derivatives of the present invention are preparable by reacting a perchlorophosphazene of formula ~ Cl P ~ -(N=PC12-)r~-(Cl)n with the products R-Q-H and Rf-cH2o(cH2cH2o)sH previously treated with a base.
According to a preferred embodiment, the aromatic compound of formula R-Q-H is dissolved in a proper organic solvent, such as diethyl ether or glyme, and is reacted with a base, such as e.g. an alkaline metal iodide (for example NaH or KH), an alkaline metal (for example Na'or K), an-alkali (ESTIEP) -- 1 o - metal fluoride (for example KF or CsF), an alkali _ metal hydroxide (for example NaOH or KOH), a carbonate or bicarbon-ate, or an amine (for example a tertiary amine). To the prod-uct so obtained, a perchlorophosphazene of formula ~ C14P ~ --(N=PC12-)m-(Cl)n is added in such amounts that the molar ratio of aromatic compound to perch10roPhosPhazene ranges from 2:1 to 5:1, preferab1y from 3:1 to 4:1. The reaction tem-perature generally ranges fro,~ the room temperature to the boiling temperature of the utilized solvent, with reaction times which can vary from 1 hour to 10 hours. The resulting product is then reacted with a hydroxy-terminated perfluoro-polyether of formula Rf-CH20(CH2CHzO)sH, converted into al-coholate by reaction with one of the bases described above for the aromatic compounds R-Q-H. rhe molar ratio of per-fluoropolyethereal compound to perchlorophosphazene general-ly ranges from 2:1 to 5:1, preferably from 3:1 to 4:1. The re-action conditions are the same as described above for the re-action with the R-Q-H compounds.
The step sequence is not determinant, wherefore it is also possible to react with perchlorophosphazene first the hydroxy-terminated perfluoropolyether and then the aromatic compound R-Q-H.
As an alternative, the reaction can be conducted in one step by reacting perchlorophosphazene with products R-Q-H and Rf-CH20(CH2CH20)sH in admixture with each other and (EST/EP) - 2I0273~

previously treated with a base.
The perfluoropolyethers having neutral end groups, utilizable for the formulation of oils and greases are avail-able on the market under the tr~de-names Fomblin (R) (Ausi-mont), Krytox(R) (DuPont~, Demnum(R) (Daikin), etc. As an example, the following classes of perfluoropolyethers can be cited:
(1) A0-(CF-CF20)m(CFXO)n-A' where X is -F or -CF3; A and A', like or different from each other, are -CF3, -C2F5 or C3F7; m and n are numbers such that the viscosity of the product ranges from 10 to 4000 cSt, the various units being statistically distribut-ed along the chain. These products can be obtained by photooxidation reaction of hexafluoropropene, according to what is described in GB patent 1,104,4~32, and by suc-cessive conversion of the end groups into neutral groups conforming to ~he process described in GB patent1,226,566.
(2) C3F70-(C.--CF20)m-B

where B is -C2F5 or -C3F7, while m is such a number that the viscosity is in the above indicated range. These products can be prepared by ionic oligomerization of the hexafluoropropene epoxide and successive treatment with fluorine according to what is described in ~.S. patent (EST/EP) - -- - 12 - ~1027~tg 3,242,218.
( 3 ) [C3F70- (CF-CF20) ",-CFCF31 2 where m is such a number that the viscosity is in-the above indicated range. These products are obtained by ionic te-lomerization of ihe hexafluoropropene epoxide and by suc-cessive photochemical dimerization, according to what is described in U.S. patent 3,2t4,478.
(4J AO-tCF~CF2O)~(~F~O)~(CFXO)q~A~

where X is -F or -CF3; A and A', like or different from each other, are -CF3, -C2F5 or -C3F7; m, n and q are num-bers such that the viscosity is in the above indicated range. These products are obtainable by photooxidation of mixtures of C3F6 and C2F4 and by subsequent treatment with fluorine according to the process described in U.S. patent 3,665,041.

(5) A0-~C2F4~p (CF2~1 -A' where A and A', like or different from each other, are -CF3 or -C2F5; p and q are numbers such that the viscosi-ty is in the above indicated range. Thes~ products are preparable by photochemical oxidation of C2F4 accord-ing to U.S. patent 3,715,378 and by successive treatment with fluorine according to U.5. patent 3,665,041.

(6) A0-(CF2CF2CF20) -A' (EST/EP'~

- 13 ~ 7 ~ ~
-where A and A', like or different from each other, are -CF3, -C2Fs or -C3F7; m is such a number that the viscosity of the product is in the above indicated range. These products are obtained according to what is described in patent application EP 148,482.

(7) AO-(CF2CF2O)r-A' where A and A', like or different from each other, are -CF3 or -C2F5; r is such a number that the viscosity of the product is in the above indicated range. These products are obtained according to what is described in U.S. patent 4,523,039.

(8) CF3 Rf Rf R' f- C-O- C - C - O -R' f CF3 Rf Rf n where R' f iS a perfluoroalkyl, n is a number > 8, Rf is -F or a perfluoroalkyl. These products are described in International Publication Number W0-87/00538, published 29 January, 1987.
A grease based on perfluoropolyethers is typi-cally composed for 15-40~ by weight of polytetrafluoroethylene, acting as a thickening agent, and for 60-85~ by weight of a liquid perfluoropolyether, besides minor amounts of other products, such as perfluoro-alkyl surfactants or polyoxyperfluoroalkyl surfactants, or other additives known in the art, such as stabilizers, anticorrosive agents, anti-wear agents etc. Additives of this type are usually contained also in A

oils based on perfluoropolyetherS, rhe phosphazene deri~atives of the present inven-tion, besides exerting a s~abilizing action, are also effect-ive as anti-wear additives for oils and greases based on per-fluoropolyethers.
The present invention is her~inafter described more in detail in the following examples, which are given merely to illustrate but not to limit the scope of the in-vention.

A three-neck flask of 1 liter volume was equipped with a condenser, a dropping funnel, inlet and outlet devices for nitrogen and a magnetic stirrer. All the reaction steps were conducted in an inert nitrogen'atmosphere.
A solution of phenol (2.7 g, 28.7 millimoles) in anhydrous diethylether (25 ml) was dropwise added to a suspension of NaH (0.6 9, 25.8 mmoles) in anhydrous diethyl-ether (50 ml). To the resulting mixture, heated at reflux for 1 hour, a solution of hexachlorocyclophosphazene (NPC12)3 (2.8 g, 8 mmoles) in anhydrous diethylether (30 ml) was added once in a time. The whole was then heated at re-flux for 1 hour.
A solution in anhydrous diethylether (30 ml) of hydroxy-terminated Fomblin(R) Y (26.5 g, 29.4 mmoles), hav-ing formula RfCH20H, where Rf is corresponding to formula (ESTteP) _ - 15 -(II), having an equivalent weight equal to 900 and a ratio of units C3 to units Cl equal to 36.8, was added dropwise to a sus-pension of NaH (0.6 g, 25.8 mmoles) in anhydrous diethylether (50 ml). The resulting mixture was heated at reflux for 1 hour.
Then, the solution obtained from the preceding reaction was added in a unique portion. After a 2-hour heating at reflux, the reaction mixture was treated with 200 ml of demineralized water and then was subjected to extraction with A113 (CC12FCClF2).
After removal of the solvent by evaporation at reduced pres-sure, a viscous liquid was obtained, which was purified by distilling-off the unreacted hydroxy-terminated Fomblin(R) Y
(at 120~C and 10 millibar).
The liquid product so purified was distilled at re-duced pressure. Two fractions were obtained: the first frac-ti~on (6.4 9; b.p. 170~-1~0~C at 10 3 mbar) had an average mol-ar composition corresponding to formula ~ (N=P)(--R-Q)(-OCH2R~)~3 (product la); the second fraction (8.7 9; b.p. 180~-200~C at 10 3 mbar) had an average molar composition corresponding to Q 0.83( ~CH2Rf)l 16 ~ 3 (product lb).
The elemental analysis of the products so obtained revealed the absence of chlorine, what confirmed that the substitution reaction had been completed. The average compos-ition was determined by H NMR analysis.

Operating under the same conditions described in ex-(EST/EP) 21Q273~

ample 1, a solution of 3-nitrophenol (3.96 9, 28.5 mmo1esJ in anhydrous diethylether (25 ml) was added dropwise to a suspen-sion of NaH (0.6 9, 25.8 mmoles) in anhydrous diethylether (50 ml). The resulting mixture was heated at reflux for 1 hour.
Then, a solution of (NPC12)3 (2.8 9, 8 mmoles) in anhydrous d~-ethylether (30 ml) was added in a unique portion and the whole was heated at reflux for 12 hours.
A solution of the same hydroxy-terminated Fomblin(R) Y utilized in example 1 (26.3 9, 28.9 mmoles) in anhydrous di-ethylether (30 ml) was added dropwise to a suspension of NaH
(0.6 9, 25.8 mmoles) in anhydrous diethylether (50 ml). The resulting mixture was heated at reflux for 1 hour. The sol-ution obtained from the preceding reaction was then added in a unique portion. After a 2-hour heating at reflux, 200 ml of demineralized water were added. Then, an extraction with A113 (CC12fCClf2). After removal of the solvents by evaporation at reduced pressure, a viscous liquid was obtained, which was purified by distilling-off the unreacted hydroxy-terminated Fomblin(R) Y (at 120~C and at 10 mbar) and then by causing the product to pass on a silica gel column, utilizing A113 as an eluent. Obtained were 15 9 (conversion: 52X) of a vis-cous, transparent and colorless liquid, which was identified, through elemental analysis, H-NMR analysis and 31P-NMR an-alysis, as a mixture of substitution products corresponding to the average formula ~ (N=P)(-R-QJ(-OCH2Rf) ~3 (product 2).

(EST/EP) ~102739 ~-- - 17 -Operating under the same conditions as described in example 1, a solution of 4-methoxyphenot (3.4 9, 28 mmoles) in anhydrous diethylether (25 ml) was added dropwise to a sus-pension of NaH (0.6 9, 25.8 mmo1es) in anhydrous diethylether ~50 ml). The resulting mixture was heated at reflux for 1 hour. Then, a solution of C NPC12 ~3 (3.0 g, 8.6 mmoles) in anhydrous diethylether was added in a unique portion, and the whole was heated at reflux for 12 hours.
A solution of the same hydroxy-terminated Fomblin( ) Y utilized in example 1 (27.0 9, 29.8 mmoles) in anhydrous di-ethylether (25 ml) was added dropwise to a suspension of NaH
(0.6 9, 25.8 mmolesJ in anhydrous diethylether (50 ml). The resulting mixture was heated at reflux for 1 hour. Then, the solution obtained from the preceding reaction was added in a unique portion. After a 2-hour heating at reflux, 200 ml of demineralized water were added. An extraction with A113 (CC12FCClF2) was then effected. After removal of the solvents by evaporation at reduced pressure, a viscous liquid was ob-tained, which was purified by distilling-off the unreacted hydroxy-terminated Fomblin(R) Y (at 120~C and at 10 3 mbar) and by causing the product to pass on a silica gel column, using A113 as an eluent. Obtained were 13 9 (conversion :
52%J of a viscous, transparent and colorless liqùid, which was identified, through elemental analysis, 1H-NMR and 31p (ESTJEP) ~- - 18 --NMR analyses~ as a mixture of substitution products corres-ponding to average formula C (N=P)(-R-Q-)(-OCH2R~) ]3 (prod-uct 3).

A set of tests was conducted in order to check the stability to thermo-oxidation, in the presence of ~etals, of lubricating compositions containing the phosphazene deriv-atives prepared in the preceding examples.
Into an apparatus consisting of a glass test-tube equipped with a gas inlet pipe, a vent pipe and a housing for a small disc made of an alloy of Ti, Y (4~), Al (6X), there were introduced ~0 9 of Fomblin(R) Z 25, corresponding to formula CF30-~CzF40) (CF ~) -Cf and having a kinematic vis-cosity equal to 25 cSt at 20~C, additioned with the phosph-azene derivative in the ~mounts indicated in Table I. The test tube was heated to a temperature of 316~C in an alumi-nium furnace. The air, after dehumidification and purific-ation, was made to bubble into the perfluoropolyethereal fluid for 72 hours, at a flowrate of 1 liter/hour.
For comparative purposes, also a test on stabilizer--free perfluoropolyether was conducted. The obtained data are reported in Table I. The stabilizer effectiveness was evaluat-ed by me~uring, on conclusion of the test, the X variation of weight ( ~ p ) and viscosity (~ ~ LJof the lubricant and the weight variation per unit of surface of the metal alloY sam-(ESTtEP) 21~273~

ple ( p ).
TABLE I

Stabilizer Conc. ~pL ~L ~p (Z b.wg.) (~ ) (mg/cm2) -- -- -100 n.d. --Product-la 0,80 -0,9 +5,7 0 Product lb o,go -3,3 -16,1 0 Product 2 0,85 -0,7 +1,8 +0,13 Product 3 0,85 -15,1 -0,2 0 .
n.d. : not determinable.

(ESTIE~')

Claims

1. Phosphazene derivatives of cyclic or linear structure, having formula:

where:
n is 0 in the case of a cyclic structure, n is 1 in the case of a linear structure;
m is an integer from 3 to 7;
groups A, like or different from one another, are selected from:
(i) R-Q-, where Q is a divalent group selected from the group consisting of:
-O-, -S-, -NR1- (in which R1 is hydrogen or a C1-C4 alkyl), and -NH-NH- ; and R is selected from the group consisting of C6-C12 aryl groups, and C6-C12 aryl groups substituted by one or more groups selected from the group consisting of:
C1-C4 alkyls, -OR2, - NR3R4, -NO2, - F and -Cl, where R2, R3 and R4 are hydrogen or C1-C4 alkyls;
(ii) R f-CH2O(CH2CH2O)8-, wherein: s = 0, 1 or 2; R f is a perfluoropolyethereal chain having a molecular weight ranging from 400 to 10,000 and composed of repeating units selected from:
(a) and (CFXO), where X is -F or -CF3;
(b) (CF2CF2O) and (CF2O);
(c) , (CF2CF2O) and (CFXO), where X is -F

or -CF3;
(d) ;

(e) (CYZ-CF2CF2O), where Y and Z, like or different from each other, are F, Cl or H;
(f) (CF2CF2O);
the various repeating units being statistically distributed along the chain;
such that at least one group of type (i) and at least one group of type (ii) are present in the phosphazene derivative molecule;
and such that groups -R-Q, if linked to the same phosphorus atom, are capable of forming a cyclic structure with the following formula:

.

2. The phosphazene derivatives of claim 1, wherein n=0, and having a molar ratio of groups R f-CH2O(CH2CH2O)8- to groups R-Q- ranging from about 0.2 to about 1.8.

3. The phosphazene derivatives of claim 2, wherein the molar ratio of groups R f-CH2O(CH2CH2O)8- to groups R-Q- ranges from about 0.5 to about 1.

4. The phosphazene derivatives of claim 1, wherein m is 3 or 4.

5. The phosphazene derivatives of claim 3, wherein m is 3 or 4.

6. The phosphazene derivatives of claim 1, wherein the perfluoropolyethereal chains R f have a molecular weight ranging from 400 to 4,000.

7. The phosphazene derivatives of claim 5, wherein the perfluoropolyethereal chains R f have a molecular weight ranging from 400 to 4,000.

8. The phosphazene derivatives of claim 1, wherein the perfluoropolyethereal chains R f are selected from the group consisting of:
(a) where:
T is a fluoroalkyl group selected from the group consisting of:
-CF3, -C2F5, -C3F7, -CF2Cl, -C2F4Cl, -C3F6Cl;
x is -F or -CF3;
Z is -F, -Cl or -CF3; and, m and n are numbers such that the n/m ratio ranges from 0.01 to 0.5 and the molecular weight is in the range 400 - 4,000;
(b) T I-O-(CF2CF2O)p(CF2O)q-CFZI-where:
TI is a fluoroalkyl group selected from:
-CF3, -C2F5, -CF2C1, -C2F4C1;
Z I is -F or -Cl;
p and q are numbers such that the q/p ratio ranges from 0.5 to 2 and the molecular weight is in the range 400 - 4,000;
(c) where:
T II is a fluoroalkyl group selected from:
-CF3, -C2F5, -C3F7, -CF2Cl, -C2F4Cl, -C3F6Cl;
X II is -F or -CF3;
Z II is -F, -Cl or -CF3;
s and t are numbers such that r + s ranges from 1 to 50, the t/(r+s) ratio ranges from 0.01 to 0.05 and the molecular weight is in the range 400 - 4,000;
(d) where:
T III is -C2F5 or -C3F7;
u is a number such that the molecular weight is in the range 400 - 4,000;
(e) T IV-O-(CYZ-CF2CF2O)v-CYZ-CF2-where:
Y and Z, like or different from each other, are F, Cl or H;
T IV is -CF3, -C2F5 or -C3F7;
v is a number such that the molecular weight is in the range 400 - 4,000;
(f) T V-O-(CF2CF2O)w-CF2-where:
T V is -CF3 or -C2F5;
w is a number such that the molecular weight is in the range 400 - 4,000.

9. The phosphazene derivatives of claim 7, wherein the perfluoropolyethereal chains R f are selected from the group consisting of:
(a) where:
T is a fluoroalkyl group selected from the group consisting of:
-CF3, -C2F5, -C3F7, -CF2Cl, -C2F4Cl, -C3F6Cl;
x is -F or -CF3;
Z is -F, -Cl or -CF3; and, m and n are numbers such that the n/m ratio ranges from 0.01 to 0.5 and the molecular weight is in the range 400 - 4,000;
(b) T I-O-(CF2CF2O)p(CF2O)q-CFZ I-where:
T I is a fluoroalkyl group selected from:
-CF3, -C2F5, -CF2Cl, -C2F4Cl;
Zl is -F or -Cl;
p and q are numbers such that the q/p ratio ranges from 0.5 to 2 and the molecular weight is in the range 400 - 4,000;
(c) where:
T II is a fluoroalkyl group selected from:
-CF3, -C2F5, -C3F7, -CF2Cl, -C2F4Cl, -C3F6Cl;
X II is -F or -CF3;
Z II is -F, -Cl or -CF3;
s and t are numbers such that r + s ranges from 1 to 50, the t/(r+s) ratio ranges from 0.01 to 0.05 and the molecular weight is in the range 400 - 4,000;
(d) where:
T III is -C2F5 or -C3F7;
u is a number such that the molecular weight is in the range 400 - 4,000;
(e) T IV-O-(CYZ-CF2CF2O)v-CYZ-CF2-where:
Y and Z, like or different from each other, are F, Cl or H;
T IV is -CF3, -C2F5 or -C3F7;
v is a number such that the molecular weight is in the range 400 - 4,000;
(f) T V-O-(CF2CF2O)w-CF2-where:
T V is -CF3 or -C2F5;
w is a number such that the molecular weight is in the range 400 - 4,000.

10. A process for preparing the phosphazene derivatives of any one of claims 1-8 or 9, wherein a perchlorophosphazene of formula:
[Cl4P]n-(N=PCl2-)m-(Cl)n, wherein n and m are numbers such that the n/m ratio ranges from 0.01 to 0.5, is reacted with an aromatic compound of formula R-Q-H and a perfluoropolyether compound of formula R f-CH2O(CH2CH2O)8-OH, where R-Q- and R f-CH2O(CH2CH2O)8- are as defined in claim 1, previously treated with a base.

11. The process of claim 10, wherein the base is an alkaline metal hydride.

12. The process of claim 10, wherein the perchlorophosphazene is first reacted with the aromatic compound R-Q-H, previously treated with the base, in such amounts that the molar ratio of aromatic compound to perchlorophosphazene ranges from 2:1 to 5:1, and then with the perfluoropolyethereal compound R f-CH2O(CH2CH2O)8-OH, previously treated with the base, in such amounts that the molar ratio of perfluoropolyethereal compound to perchlorophosphazene ranges from 2:1 to 5:1.

13. The process of claim 11, wherein the perchlorophosphazene is first reacted with the aromatic compound R-Q-H, previously treated with the base, in such amounts that the molar ratio of aromatic compound to perchlorophosphazene ranges from 2:1 to 5:1, and then with the perfluoropolyethereal compound R f-CH2O(CH2CH2O)8-OH, previously treated with the base, in such amounts that the molar ratio of perfluoropolyethereal compound to perchlorophosphazene ranges from 2:1 to 5:1.

14. The product produced by the process of claim 10.

15. The product produced by the process of any one of claims 11, 12 or 13.

16. Lubricating compositions comprising:
(a) an oil or a grease based on perfluoropolyethers;
(b) from 0.05 to 3% by weight of the phosphazene derivative of claim 1 - 8 or 9.

17. The lubricating compositions of claim 16, wherein the phosphazene derivative is contained in amounts ranging from 0.5 to 1% by weight.

18. The lubricating compositions of claim 16, wherein the perfluoropolyethers of component (a) are selected from the group consisting of:
(1) where X is -F or -CF3;
A and A', like or different from each other, are -CF3, -C2F5 or C3F7;
m and n are numbers such that the viscosity of the product ranges from 10 to 4,000 cSt, the various units being statistically distributed along the chain;
(2) where B is -C2F5 or -C3F7, while m is a number such that the viscosity of the product ranges from 10 to 4,000 cSt;
(3) where m is a number such that the viscosity of the product ranges from 10 to 4,000 cSt;

(4) where X is -F or -CF3;
A and A', like or different from each other, are -CF3, -C2F5 or -C3F7;
m, n and q are numbers such that the viscosity of the product ranges from 10 to 4,000 cSt;
(5) AO-(C2F4O)p (CF2O)q-A' where A and A', like or different from each other, are -CF3 or -C2F5;
p and q are numbers such that the viscosity of the product ranges from 10 to 4,000 cSt;
(6) AO-(CF2CF2CF2O)m-A' where A and A', like or different from each other, are -CF3, -C2F5 or -C3F7;
m is a number such that the viscosity of the product ranges from 10 to 4,000 cSt;
(7) AO-(CF2CF2O)r-A' where A and A', like or different from each other, are -CF3 or -C2F5;
r is a number such that the viscosity of the product ranges from 10 to 4,000 cSt; and, (8) where R'f is a perfluoroalkyl, n is a number ~ 8, R f is -F or a perfluoroalkyl.

19. The lubricating compositions of claim 17, wherein the perfluoropolyethers of component (a) are selected from the group consisting of:
(1) where X is -F or -CF3;
A and A', like or different from each other, are -CF3, -C2F5 or C3F7;

m and n are numbers such that the viscosity of the product ranges from 10 to 4,000 cSt, the various units being statistically distributed along the chain;
(2) where B is -C2F5 or -C3F7, while m is a number such that the viscosity of the product ranges from 10 to 4,000 cSt;
(3) where m is a number such that the viscosity of the product ranges from 10 to 4,000 cSt;
(4) where X is -F or -CF3;
A and A', like or different from each other, are -CF3, -C2F5 or -C3F7;
m, n and q are numbers such that the viscosity of the product ranges from 10 to 4,000 cSt;
(5) AO-(C2F4O)p (CF2O)q-A' where A and A', like or different from each other, are -CF3 or -C2F5;
p and q are numbers such that the viscosity of the product ranges from 10 to 4,000 cSt;
(6) AO-(CF2CF2CF2O)m-A' where A and A', like or different from each other, are -CF3, -C2F5 or -C3F7;
m is a number such that the viscosity of the product ranges from 10 to 4,000 cSt;
(7) AO-(CF2CF2O)r-A' where A and A', like or different from each other, are - CF3 or -C2F5;
r is a number such that the viscosity of the product ranges from 10 to 4,000 cSt; and, (8) where R'f is a perfluoroalkyl, n is a number ~ 8, R f is -F or a perfluoroalkyl.

20. Use of the phosphazene derivatives of any one of claims 1-8 or 9 as stabilizers for oils and greases based on perfluoropolyethers.

21. Use of the phosphazene derivatives of any one of claims 1- 8 or 9 as anti-wear additives for oils and greases based on perfluoropolyethers.