DE102010001070A1 - Lubricant composition, useful to reduce friction between moving surfaces e.g. metallic surface, standing in contact with each part, comprises ionic liquids, phosphoric acid esters, and optionally solvents, and additives e.g. bactericides - Google Patents

Abstract

Lubricant composition based on ionic liquids comprises at least 70-99.99 wt.% of ionic liquid(s), at least 0.01-5 wt.% of phosphoric acid ester(s), optionally 0-15 wt.% of solvent(s), and optionally 0-10 wt.% of additive(s) comprising corrosion inhibitors, defoamers, bactericides, detergent-active compounds, metal deactivators or solid lubricants.

Description

The invention relates to the use of alkoxylated phosphate acid esters as wear protection additive for ionic liquids, which are used as lubricants. Lubricant is understood to mean a substance that optimizes the relative movement between two solid surfaces that are loaded. Another object is to dissipate the frictional heat. Ideally, the surfaces, in particular metal surfaces, are completely separated (hydrodynamic lubrication). As a result, the loss of friction is low and the mechanical wear is zero. Under higher loads, especially in gears between the contact points of the tooth flanks, the metallic contact can lead to wear. The addition of film-forming anti-wear agents which combine with the surfaces of the metal parts, either by physical adsorption or by a chemical reaction, prevents metallic contact between the sliding partners.

State of the art:

Ionic liquids and their special properties as lubricants are already in the patent DE 10 2007 036 771 by Evonik Goldschmidt GmbH. For the purposes of the present invention, ionic liquids are, at low temperatures (<100 ° C.), termed melting salts which represent a novel class of liquids and are composed exclusively of ions. ( KR Seddon J. Chem. Technol. Biotechnol. 1997, 68, 351-356 ).

The ionic liquids have no measurable vapor pressure, are nonflammable, and have a very high thermal stability. These properties make them of interest as lubricants, especially in applications where conventional hydrocarbon based lubricants have weaknesses. Ionic liquids consist of anions and cations, which can be selected so that the resulting ionic liquid has very low temperature dependence of viscosity (corresponding to a high viscosity index) and extremely good low-temperature flow behavior. The ionic liquids are also extremely resistant to oxidation. These intrinsic properties of ionic liquids can only be made in hydrocarbon-based oils, but especially in mineral oil-based lubricants with a high use of additives, and make them more susceptible to failure. Due to the very good described intrinsic properties of many ionic liquids, they come with significantly fewer additives.

An essential parameter for lubricants is the wear protection for mutually moving surfaces. For transmission oils, the task of preventing wear is even a major function. The desired performance of the ionic liquids as a lubricant can be significantly improved by the use of suitable additives. Conventional anti-wear additives are hydrocarbon-based systems designed as oil-like lubricants and are not soluble in ionic liquids. These include z. As dialkyl and Diarylpolysulfide, alkyl and aryl halides, Metaldialkyl (-aryl, -aclaryl) dithiophosphates, monocarboxylic acids and their esters, saturated fatty acids.

Task:

The object of the present invention was therefore to provide an additive for these ionic liquids, which improves the anti-wear properties of the ionic liquid or of mixtures of different ionic liquids. The wear protection additive should act in small amounts, and be soluble in the ionic liquid to ensure storage stability.

Surprisingly, it has been found that certain phosphate esters significantly reduce the friction in the mixed friction region as well as in the boundary region at low use concentrations in ionic liquids.

The subject of the invention is therefore lubricant compositions based on one or more ionic liquids containing at least one friction-reducing phosphoric acid ester additive.

Another object of the invention is the use of alkoxylated phosphoric acid esters as wear protection additive in ionic liquids.

With the use of the additive according to the invention between 0.01 and 5 wt .-%, preferably between 0.1 and 0.5 wt .-% in an ionic liquid or in a mixture of several ionic Liquids, the friction of the moving, in contact with each other parts z. B. are significantly reduced in a transmission, and thus synonymous durability of the components and the efficiency of the component can be increased. According to today's ideas, the additives of the invention develop their effect as wear protection additive by activation temperatures and loads z. B. pressure. They form adhesive films on the surfaces and serve essentially as a solid lubricant to prevent contact between the surfaces under extreme loads.

As surfaces to be lubricated, in principle, all surfaces can be used. Preference is given to glassy, ceramic or metallic surfaces, particularly preferably surfaces of ferrous metals such as iron, nickel, cobalt, manganese or chromium and in particular steel surfaces.

wobei
R¹ ein Polyetherrest der Formel II [O(C₂H_4-dR'_dO)_m(C_xH_2xO)_rZ] (II) ist, mit der Bedeutung
d 0 bis 3, bevorzugt 0 oder 1,
r > 0, bevorzugt 1–10, besonders bevorzugt 3–7,
x 2 bis 10, bevorzugt 2
m ≥ 0
R' ein Wasserstoffrest, ein einwertiger Kohlenwasserstoffrest mit 1 bis 18 C-Atomen, ein aromatischer oder ein substituierter aromatischer Rest mit 6 bis 18 C-Atomen ist,
Z ein H-Atom oder ein einwertiger organischer Alkylrest Alkyl mit einem bis 30 Kohlenstoffatomen, der auch verzweigt sein kann oder ein Alkylester mit 1 bis 30 Kohlenstoffatomen oder ein Arylester mit 7 bis 30 Kohlenstoffatomen ist,
R² eine O-Alkylgruppe mit 1-30 Kohlenstoffatomen oder R¹ oder -OH ist,
R³ eine O-Alkylgruppe mit 1-30 Kohlenstoffatomen oder R¹ oder -OH ist.The lubricant compositions according to the invention based on ionic liquids contain alkoxylated phosphate esters according to formula I or Ia:

in which
R ^{1 is} a polyether radical of the formula II [O (C ₂ H _4-d R ' _d O) _m (C _x H ₂ O) _r Z] (II) is, with meaning
d is 0 to 3, preferably 0 or 1,
r> 0, preferably 1-10, more preferably 3-7,
x 2 to 10, preferably 2
m ≥ 0
R 'is a hydrogen radical, a monovalent hydrocarbon radical having 1 to 18 C atoms, an aromatic or a substituted aromatic radical having 6 to 18 C atoms,
Z is an H atom or a monovalent organic alkyl radical alkyl having one to 30 carbon atoms, which may also be branched or is an alkyl ester having 1 to 30 carbon atoms or an aryl ester having 7 to 30 carbon atoms,
R ^{2 is} an O-alkyl group having 1-30 carbon atoms or R ¹ or -OH,
R ^{3 is} an O-alkyl group of 1-30 carbon atoms or R ¹ or -OH.

mit t = 0 oder 1.According to the invention, it is also possible to use esters of diphosphoric acids and triphosphoric acids of the formula Ia,

with t = 0 or 1.

Lubricating compositions according to the invention are anti-wear additives and have structures with identical or different radicals R ¹ and R ² and R ³ and also mixtures of different phosphate acid esters of formula (I) or / and of formula (Ia).

Preferred radicals Z are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, capryl, lauryl, cetyl, myristyl, palmityl, stearyl, linoleyl, linolenyl, arachidyl, gadoleyl, behenyl and / or oleyl. Preferred phosphate acid esters are those in which in the radical of the formula (II) the sum m + r = 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, particularly preferably with m + r = 3, 4, 5, 6.

The phosphoric acid esters can be present in mixtures with one another or else mixtures of mono-, di- and / or triphosphoric acid esters. Particular preference is given to low-alkoxylated phosphoric esters having 2, 3, 4 or 5 EO groups (ethylene oxide units) which, as alkyl group Z, include capryl, lauryl, cetyl, myristyl, palmityl, stearyl, linoleyl, linolenyl, arachidyl, gadoleyl, behenyl and / or oleyl or mixtures thereof.

The phosphoric acid esters may be liquid or solid at room temperature, in particular liquid at the use temperatures between + 20 ° C and + 120 ° C. Preferably, the phosphoric acid esters according to the invention are optically clear in the ionic liquids.

The nephelometric turbidity value (unit NTU) is at room temperature in the formulations between 0 and 500 NTU, preferably between 0 and 50 NTU, more preferably between 0 and 5 NTU and most preferably between 0 and 1 NTU. In particular, the increase in the nephelometric turbidity value of the overall formulation (unit NTU) by adding the phosphoric acid ester according to the invention is limited to 0 to 50 NTU, preferably 0 to 5 NTU and more preferably 0 to 1 NTU.

The turbidity value of a 1% strength by weight solution of the phosphoric acid ester in the ionic liquid is in any event less than 50 NTU at room temperature.

The phosphoric acid esters to be used in the lubricant compositions of the present invention have a phosphorus content of 0.1 to 15% by weight.

The subject lubricant compositions may contain solvents.

Surprisingly, the inventive wear protection additives tolerate the solvents without losing their effect. In particular, portions of hydrophilic solvents such as water, alcohols, glycols do not adversely affect the wear protection. For technical reasons, however, the ionic liquids as lubricants usually contain only relatively small amounts of hydrophilic solvents, preferably less than 5% by weight and in particular less than 1% by weight.

The concentration of the phosphoric acid esters in the ionic liquid (s) is at most 5% by weight, preferably less than 3% by weight, more preferably less than 1% by weight and in particular between 0.01 to 1.0% by weight. ,

• a) zumindest 80–99,99 Gew.-% einer oder mehrerer ionischer Flüssigkeiten,
• b) zumindest 0,01–5 Gew.-% eines oder mehrerer Phosphorsäureesters,
• c) optional 0 bis 15 Gew.-% eines oder mehrerer Lösungsmittel,
• d) optional 0 bis 10 Gew.-% eines oder mehrerer Zusatzstoffe ausgewählt aus der Gruppe der Korrosionsinhibitoren, Entschäumer, Bakterizide, Detergent-Wirkstoffe, Metalldesaktivatoren und/oder Festschmierstoffe,

wobei sich die Komponenten a bis d zu 100 Gew.-% ergänzen.The invention also provides a lubricant composition based on one or more ionic liquids containing

• a) at least 80-99.99% by weight of one or more ionic liquids,
• b) at least 0.01-5% by weight of one or more phosphoric acid esters,
• c) optionally 0 to 15% by weight of one or more solvents,
• d) optionally 0 to 10 wt .-% of one or more additives selected from the group of corrosion inhibitors, defoamers, bactericides, detergent active ingredients, metal deactivators and / or solid lubricants,

wherein the components a to d supplement to 100 wt .-%.

As ionic liquid, it is possible to use all compounds which are of ionic composition and are liquid in a temperature range from -75.degree. C. to + 350.degree. C., preferably from -50.degree. C. to + 300.degree. C., and have a very low vapor pressure relative to the ambient pressure ,

Ionic liquids and their special properties as lubricants are already in the patent application DE 10 2007 036 771 by Evonik Goldschmidt GmbH. For the purposes of the present invention, ionic liquids are, at low temperatures (<100 ° C.), termed melting salts which represent a novel class of liquids and are composed exclusively of ions. ( KR Seddon J. Chem. Technol. Biotechnol. 1997, 68, 351-356 ). The content of the above two References herein are hereby incorporated in full as part of this specification with respect to the definition of the ionic liquids and the structures described therein.

Ionic liquids in the sense of the present invention are preferably salts of the general formulas III, IV or V listed below: [A] ^{n +} [Y] ^n- (III) in which n is 1, 2, 3 or 4, [A] ^{+ is} a quaternary ammonium cation, an oxonium cation, a sulfonium cation or a phosphonium cation, and [Y] ^{n- is} a one, two or more -, tri- or tetravalent anion stands; or
mixed salts of the general formulas IV [A1] ⁺ [A2] ⁺ [Y] ^2- (IVa); [A1] ⁺ [A2] ⁺ [A3] ⁺ [Y] ^3- (IVb); or [A1] ⁺ [A2] ⁺ [A3] ⁺ [A4] ⁺ [Y] ^4- (IVc), wherein [A1] ⁺ , [A2] ⁺ [A3] ⁺ and [A4] ^{+ are} independently selected from the groups mentioned for [A] ⁺ and [Y] ^{n- has} the meaning given for formula III; or
mixed salts of the general formulas V [A1] ⁺ [A2] ⁺ [A3] ⁺ [M1] ⁺ [Y] ^4- (Va); [A1] ⁺ [A2] ⁺ [M1] ⁺ [M2] ⁺ [Y] ^4- (Vb); [A1] ⁺ [M1] ⁺ [M2] ⁺ [M3] ⁺ [Y] ^4- (Vc); [A1] ⁺ [A2] ⁺ [M1] ⁺ [Y] ^3- (Vd); [A1] ⁺ [M1] ⁺ [M2] ⁺ [Y] ^3- (Ve); [A1] ⁺ [M1] ⁺ [Y] ^2- (Vf); [A1] ⁺ [A2] ⁺ [M4] ²⁺ [Y] ^4- (Vg); [A1] ⁺ [M1] ⁺ [M4] ²⁺ [Y] ^4- (Vh); [A1] ⁺ [M5] ³⁺ [Y] ^4- (Vi); or [A1] ⁺ [M4] ²⁺ [Y] ^3- (Vj) wherein [A1] ⁺ , [A2] ⁺ and [A3] ^{+ are} independently selected from the groups mentioned for [A] ⁺ , [Y] ^{n- has} the meaning given for formula III and [M1] ⁺ , [M2] ⁺ , [M3] ⁺ monovalent metal cations, [M4] ²⁺ divalent metal cations and [M5] ³⁺ trivalent metal cations;
or mixtures of all formulas III-V.

The ionic liquids used according to the invention are preferably composed of at least one quaternary nitrogen and / or phosphorus compound and / or sulfur compound and at least one anion and their melting point is below about + 250 ° C, preferably below about + 150 ° C, especially below approx. + 100 ° C. Particularly preferably, the ionic liquids used according to the invention or their mixtures are liquid at room temperature.

The wear protection additive according to the invention is metered into the preferably used ionic liquids which consist for example of at least one cation of the general formulas: R ¹ R ² R ³ R ⁴ N ⁺ (VI) R ¹ R ² N ⁺ = CR ³ R ⁴ (VII) R ¹ R ² R ³ R ⁴ P ⁺ (VIII) R ¹ R ² P ⁺ = CR ³ R ⁴ (IX) R ¹ R ² R ³ S ⁺ (X) in which
R ¹ , R ² , R ³ , R ^{4 are} identical or different and are hydrogen, a linear or branched optionally double bonds containing aliphatic hydrocarbon radical having 1 to 30 carbon atoms, an optionally double bonds containing cycloaliphatic hydrocarbon radical having 5 to 40 carbon atoms, an aromatic hydrocarbon radical with 6 to 40 carbon atoms, an alkylaryl radical having 7 to 40 carbon atoms, a linear or branched by one or more heteroatoms (oxygen, NH, NR 'with R' equal to an optionally double bonds containing C ₁ -C ₃₀ alkyl, in particular -CH ₃ ) interrupted optionally double bonds containing aliphatic hydrocarbon radical having 2 to 30 carbon atoms, one by one or more functionalities selected from the group -OC (O) -, - (O) CO-, -NH-C (O) -, - (O) C -NH, - (CH ₃ ) NC (O) -, - (O) CN (CH ₃ ) -, -S (O ₂ ) -O-, -OS (O ₂ ) -, -S (O ₂ ) - NH, -NH-S (O ₂ ) -, -S (O ₂ ) -N (CH ₃ ) -, -N (CH ₃ ) -S (O ₂ ) -, interrupted linear or branched optionally double bonds containing aliphatic hydrocarbon radical having 2 to 30 carbon atoms, one terminal OH, OR ', NH ₂ , N (H) R', N (R ') ₂ (where R' is an optionally double-bond-containing C ₁ -C ₃₀ -alkyl radical) functionalized linear or branched optionally double bonds containing aliphatic or cycloaliphatic hydrocarbon radical having 1 to 30 carbon atoms or a blockwise or random polyether according to - (R ⁵ -O) _n -R ⁶ ,
in which
R ^{5 is} a linear or branched hydrocarbon radical containing 2 to 4 carbon atoms,
n is 1 to 100, preferably 2 to 60, and
R ^{6 is} hydrogen, a linear or branched optionally double bonds containing aliphatic hydrocarbon radical having 1 to 30 carbon atoms, an optionally double bonds containing cycloaliphatic hydrocarbon radical having 5 to 40 carbon atoms, an aromatic hydrocarbon radical having 6 to 40 carbon atoms, an alkylaryl radical having 7 to 40 carbon atoms means or Rest -C (O) -R ⁷ with
R ⁷ is a linear or branched optionally double bonds containing aliphatic hydrocarbon radical having 1 to 30 carbon atoms, an optionally double bonds containing cycloaliphatic hydrocarbon radical having 5 to 40 carbon atoms, an aromatic hydrocarbon radical having 6 to 40 carbon atoms, an alkylaryl radical having 7 to 40 carbon atoms.

According to the invention, in a further particularly preferred embodiment, those ionic liquids or mixtures thereof which comprise a combination of a 1,3-dialkylimidazolium, 1,2,3-trialkylimidazolium, 1,3-dialkylimidazolinium and / or 1,2, 3-Trialkylimidazoliniumkations with an anion selected from the group of halides, bis (trifluoromethylsulfonyl) imide, Perfluoralkyltosylate, alkyl sulfates and sulfonates, perfluorinated alkyl sulfonates and sulfates, Perfluoralkylcarboxylate, perchlorate, dicyanamide, thiocyanate, isothiocyanate, tetraphenylborate, tetrakis (pentafluorophenyl) borate, Tetrafluoroborate, hexafluorophosphate included.

Further objects of the invention will become apparent from the claims, the disclosure of which is the entire subject of this description.

In addition, simple, commercially available, acyclic quaternary ammonium salts such. B. TEGO ^® IL T16ES, TEGO ^® IL K5MS, TEGO ^® IL DS or TEGO ^® IL 2MS (products of Evonik Goldschmidt GmbH) are used.

In the examples given below, the present invention is described to illustrate the invention, without the invention, the scope of application of which is apparent from the entire description and the claims, to be limited to the embodiments mentioned in the examples. Given below, ranges, general formulas, or classes of compounds are intended to encompass not only the corresponding regions or groups of compounds explicitly mentioned, but also all sub-regions and sub-groups of compounds obtained by removing individual values (ranges) or compounds can be.

If documents are cited in the context of the present description, their contents are intended to form part of the disclosure content of the present invention.

Effect of the Wear Protection Additive According to the Invention:
If sliding parts (eg gearwheels) are no longer separated by the lubricant, the surfaces of the sliding partners touch each other. The result is mechanical adhesive wear. Wear protection additives then reduce the friction and welding of the contacting surfaces. The effect can be reproduced in a Stribeck curve. The Stribeck curve depicts the course of the frictional force in a coordinate system. The abscissa shows the friction coefficient, the ordinate the function of speed, pressure and viscosity. The Stribeck curve was taken with a Mini Traction Machine (MTM2) from PCS Instruments. The tribo contact results from a polished steel ball and a steel disc. Both are driven independently of each other creating a sliding / rolling contact. For the experiment, a ball and a disc were mounted. Subsequently, the test liquid was filled in the test reservoir. The program runs automatically and thus very reproducibly the entered loads, speeds, sliding-rolling conditions and temperatures.

Test results:

In order to demonstrate the mode of action of the additive to be used according to the invention, two ionic liquids were selected and measured in the Mini Traction machine. The selected ionic liquid was then mixed with 0.3% by weight of the additive according to the invention and compared with the stribeck curve of the unaddititated fluid.

Test conditions:

• Temperatures: 33 ° C, 70 ° C, 88 ° C,
• Speed range: 2500 mm / s-5 mm / s (5 measurements per temperature)
• Ratio of the speed from ball to disc: 50%
• Load (pressure on ball): 30 N, corresponds to a pressure of 947.8 MPa

Test results:

Ionic liquids used: Tego IL IMES, 1-methyl-3-ethyl-imidazolium ethylsulfate (= IL 1)

Bis (2-hydroxyethyl) dimethylammonium methyl sulfonate (= IL 2)

Inventive Wear Protection Additive:

Lauryl polyglycol (3EO) ether phosphate (phosphorus content: 5.1% by weight)

The additive to be used according to the invention was added to the ionic liquids at 0.3% by weight. The reduction in the coefficient of friction compared to the non-additized ionic liquid was measured by means of the Mini Traction machine and is given in Table 1 in percent. Ionian Fl. test temperature 33 ° C 70 ° C 88 ° C IL 1 5% 45% 55% IL 2 3% 40% 50%

The friction coefficient of the pure ionic liquid is significantly lowered with the addition of 0.3% by weight of the additive according to the invention. The additive has a strong wear-reducing effect already at a temperature of 70 ° C.

In summary, therefore, the use of an alkoxylated phosphate acid ester, as described under formula (I), for the addition of ionic liquids, as a wear protection additive is proposed. In this case, mixtures of ionic liquids are also possible as fluids to be added. The ionic liquids are used as lubricants z. B. used for transmission. The additives according to the invention significantly reduce the coefficient of friction in the mixing and boundary region and thus prevent or reduce wear.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007036771 [0002, 0025]

Cited non-patent literature

• KR Seddon J. Chem. Technol. Biotechnol. 1997, 68, 351-356 [0002]
• KR Seddon J. Chem. Technol. Biotechnol. 1997, 68, 351-356 [0025]

Claims (13)

Containing a lubricant composition based on one or more ionic liquids a) at least 70-99.99% by weight of one or more ionic liquids, b) at least 0.01-5% by weight of one or more phosphoric esters, c) optionally 0 to 15% by weight of one or more solvents, d) optionally 0 to 10 wt .-% of one or more additives selected from the group of corrosion inhibitors, defoamers, bactericides, detergents, metal deactivators, solid lubricants, wherein the components a to d supplement to 100 wt .-%. Lubricant composition according to claim 1, characterized in that as phosphoric acid ester at least one compound of formula I or Ia or mixtures thereof is used

where R ^{1 is} a polyether radical of the formula II [O (C ₂ H _4-d R ' _d O) _m (C _x H ₂ O) _r Z] (II) is, with the meaning d 0 to 3, r> 0 preferably 1-10, x 2 to 10, m ≥ 0, R 'is a hydrogen radical, a monovalent hydrocarbon radical having 1 to 18 carbon atoms, an aromatic or a substituted aromatic radical with 6 to 18 C atoms, Z is an H atom or a monovalent organic alkyl radical having 1 to 30 carbon atoms, which may also be branched or an alkyl ester having 1 to 30 carbon atoms or an aryl ester having 7 to 30 carbon atoms, R ^{2 is} a O-alkyl group having 1-30 carbon atoms or R ¹ or -OH, R ^{3 is} an O-alkyl group having 1-30 carbon atoms or R ¹ or -OH and in the case of diphosphoric or triphosphoric according to formula Ia with t = 0 or 1 , Lubricant composition according to at least one of claims 1 or 2, characterized in that Z in formula II is selected from the group of the radicals methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, capryl, lauryl, cetyl, myristyl , Palmityl, stearyl, linoleyl, linolenyl, arachidyl, gadoleyl, behenyl and / or oleyl. A lubricant composition according to at least one of claims 1 to 3, characterized in that in the radical of formula II the sum m + r = 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. A lubricant composition according to at least one of claims 1 to 4 containing less than 5% by weight of solvent. Lubricant composition according to claim 5, characterized in that the solvent is hydrophilic. Lubricant composition according to at least one of claims 1 to 6, characterized in that as ionic liquid compounds are used which are ionic and are liquid in a temperature range of -75 ° C and + 350 ° C and have a very low vapor pressure relative to the ambient pressure , Lubricant composition according to claim 7, characterized in that the ionic liquid used is salt of the general formulas III, IV or V below: [A] ^{n +} [Y] ^n- (III) in which n is 1, 2, 3 or 4, [A] ^{+ is} a quaternary ammonium cation, an oxonium cation, a sulfonium cation or a phosphonium cation, and [Y] ^{n- is} a one, two or more -, tri- or tetravalent anion stands; or mixed salts of the general formulas IV [A1] ⁺ [A2] ⁺ [Y] ^2- (IVa); [A1] ⁺ [A2] ⁺ [A3] ⁺ [Y] ^3- (IVb); or [A1] ⁺ [A2] ⁺ [A3] ⁺ [A4] ⁺ [Y] ^4- (IVc), wherein [A ¹ ] ⁺ , [A ² ] ⁺ [A ³ ] ⁺ and [A ⁴ ] ^{+ are} independently selected from the groups mentioned for [A] ⁺ and [Y] ^{n- has} the meaning given for formula III; or mixed salts of the general formulas V [A1] ⁺ [A2] ⁺ [A3] ⁺ [M1] ⁺ [Y] ^4- (Va); [A1] ⁺ [A2] ⁺ [M1] ⁺ [M2] ⁺ [Y] ^4- (Vb); [A1] ⁺ [M1] ⁺ [M2] ⁺ [M3] ⁺ [Y] ^4- (Vc); [A1] ⁺ [A2] ⁺ [M1] ⁺ [Y] ^3- (Vd); [A1] ⁺ [M1] ⁺ [M2] ⁺ [Y] ^3- (Ve); [A1] ⁺ [M1] ⁺ [Y] ^2- (Vf); [A1] ⁺ [A2] ⁺ [M4] ²⁺ [Y] ^4- (Vg); [A1] ⁺ [M1] ⁺ [M4] ²⁺ [Y] ^4- (Vh); [A1] ⁺ [M5] ³⁺ [Y] ^4- (Vi); or [A1] ⁺ [M4] ²⁺ [Y] ^3- (Vj) wherein [A ¹ ] ⁺ , [A ² ] ⁺ and [A ³ ] ^{+ are} independently selected from the groups mentioned for [A] ⁺ , [Y] ^{n- has} the meaning given for formula III and [M ¹ ] ⁺ , [M ² ] ⁺ , [M ³ ] ⁺ monovalent metal cations, [M ⁴ ] ²⁺ divalent metal cations and [M ⁵ ] ³⁺ trivalent metal cations; or mixtures of all formulas III-V are used. Lubricant composition according to claim 7 or 8, characterized in that the ionic liquid used are those which consist of 1,3-dialkylimidazolium, 1,2,3-trialkylimidazolium, 1,3-dialkylimidazolinium and / or 1,2,3-trialkylimidazolinium cations and an anion selected from the group of halides, bis (trifluoromethylsulfonyl) imide, perfluoroalkyl tosylates, alkyl sulfates and sulfonates, perfluorinated alkyl sulfonates and sulfates, perfluoroalkyl carboxylates, perchlorate, dicyanamide, thiocyanate, isothiocyanate, tetraphenylborate, tetrakis (pentafluorophenyl) borate, tetrafluoroborate, hexafluorophosphate are composed. Use of lubricant compositions according to at least one of claims 1 to 9 for reducing the friction of surfaces of moving, contacting parts. Use according to claim 10, wherein the surface is vitreous, ceramic or metallic. Use according to claim 11, wherein the surface is metallic and consists of ferrous metals or steel. Use of alkoxylated phosphoric acid esters of the formula I and / or Ia as a wear protection additive in lubricants containing ionic liquids.