EP0323403A2 - Lubricant composition - Google Patents

Abstract

The composition contains at least one lubricant, for example based on mineral oils, synthetic oils or mixtures thereof, or a hydraulic fluid and a mixture of one or more compounds from series A) and one or more compounds from series B), the compounds of series A) being of the general formula …<IMAGE>… and the compounds of series B) being of the general formula …<IMAGE>… the radicals R<1> and R<1>' being, for example, -H or alkyl having 1 to 24 C atoms and n being 0.1 or 2, R<2> and R<3> being, for example, -H, alkyl having 1 to 24 C atoms or phenyl, or R<2> and R<3> together being an alkylene group, and R<4> being, for example, an alkyl group having 4-18 C atoms or a radical …<IMAGE>… in which R<5> can be an alkyl group, and R<4> being an alkylene group and Y being O or S. The mixture confers a high stability towards oxyidation on lubricant compositions.

Description

The present invention relates to new lubricant and hydraulic fluid compositions with high stability against oxidative degradation.

It is known to add additives to lubricants, such as mineral oils or synthetic and semi-synthetic oils, to improve the properties of use.

Additives that prevent the oxidative degradation of the lubricants and ensure high storage and effectiveness are of great importance.

For this purpose, additives from the series of diphenylamines, as described in EP-A-0 149 422, are added to the lubricating oils, for example.

Furthermore, from DE-OS 28 27 253 thioketals were known which can be used as high-pressure additives in lubricants.

New lubricant compositions have now been found which have further improved properties compared to the previously known products and are distinguished by high stability against oxidative degradation.

aufweisen, in der R¹ und R¹′ gleich oder verschieden sind und -H, Alkyl mit 1 bis 24 C-Atomen, Cycloalkyl mit 5 bis 12 C-Atomen oder Phenyl-­(C₁-C₄)-alkyl bedeuten und n eine Zahl von 0, 1 oder 2 bedeutet und die verbindungen der Reihe B) die allgemeine Formel

aufweisen, in denen R² -H, Alkyl mit 1 bis 24 C-Atomen, Phenyl, mit NO₂, Cl, Br, F, C₁-C₁₂-Alkyl und/oder C₁-C₁₂-Alkoxy substituiertes Phenyl, Phenyl-(C₁-C₄)alkyl, Phenyl der allgemeinen Formel

worin R⁶ -H, Alkyl mit 1 bis 20 C-Atomen oder Phenyl-(C₁-C₄)-alkyl und x gleich 1 oder 2 ist, bedeutet oder R₂ Furyl, Tetrahydrofuryl, 2-Methyl­furyl, 2-Methyltetrahydrofuryl, Cyclohexyl oder unsubstituiertes oder mit -CH₃ substituiertes Cyclohexenyl bedeutet, oder R² für eine Gruppe der Formel

steht, wobei m = 1 und p = 0 oder 1 ist, oder m = 2 und p = 0 ist, und R⁴ jeweils die nachstehend angegebene Bedeutung hat, und R³ -H, Alkyl mit 1 bis 24 C-Atomen, Phenyl, mit NO₂, Cl, Br, F oder C₁-C₁₂-Alkyl substitu­iertes Phenyl, Phenyl-(C₁-C₄)-alkyl oder einen Phenylrest der allgemeinen Formel

bedeutet, worin R⁶ und x die angegebene Bedeutung hat oder R³

wobei m = 1 und p = 0 oder 1 ist, oder m = 2 und p = 0 ist, oder

bedeutet, wobei R⁴ jeweils die nachstehend angegebene Bedeutung hat, oder R₂ und R₃ zusammen eine -CH₂-(CH₂)₂₋₉-CH₂-Gruppe bedeuten und die Reste R⁴ gleich oder verschieden sind und Alkyl mit 4 bis 18 C-Atomen, Phenyl, Tolyl, Benzyl oder -(CH₂)

-OR⁵,

wobei
s = 1 oder 2 ist und R⁵ gleich Alkyl mit 1 bis 24 C-Atomen ist, darstel­len und R⁴′ unsubstituiertes oder C₁-C₁₂-alkylsubstituiertes Alkylen mit 1 bis 18 C-Atomen bedeutet und Y gleich O oder S ist.The present invention relates to a composition comprising at least one lubricant, in particular based on mineral oil, synthetic oils or mixtures thereof, or a hydraulic fluid, and a mixture of one or more compounds from the series A) and one or more compounds from the series B. ), the compounds of series A) having the general formula

have in which R¹ and R¹ 'are the same or different and -H, alkyl having 1 to 24 carbon atoms, cycloalkyl having 5 to 12 carbon atoms or phenyl- (C₁-C₄) alkyl and n is a number from 0 , 1 or 2 means and the compounds of series B) the general formula

have in which R² -H, alkyl having 1 to 24 carbon atoms, phenyl, substituted with NO₂, Cl, Br, F, C₁-C₁₂-alkyl and / or C₁-C₁₂-alkoxy phenyl, phenyl- (C₁-C₄ ) alkyl, phenyl of the general formula

wherein R⁶ -H, alkyl having 1 to 20 C atoms or phenyl- (C₁-C₄) alkyl and x is 1 or 2, or R₂ means furyl, tetrahydrofuryl, 2-methylfuryl, 2-methyltetrahydrofuryl, cyclohexyl or unsubstituted or is -CH₃ substituted cyclohexenyl, or R² for a group of the formula

is, where m = 1 and p = 0 or 1, or m = 2 and p = 0, and R⁴ each has the meaning given below, and R³ -H, alkyl having 1 to 24 carbon atoms, phenyl, with NO₂, Cl, Br, F or C₁-C₁₂ alkyl substituted phenyl, phenyl- (C₁-C₄) alkyl or a phenyl radical of the general formula

means in which R⁶ and x has the meaning given or R³

where m = 1 and p = 0 or 1, or m = 2 and p = 0, or

means, where R⁴ each has the meaning given below, or R₂ and R₃ together represent a -CH₂- (CH₂) ₂₋₉-CH₂ group and the radicals R⁴ are identical or different and alkyl having 4 to 18 carbon atoms, phenyl , Tolyl, benzyl or - (CH₂)

-OR⁵,

in which
s = 1 or 2 and R⁵ is alkyl with 1 to 24 C atoms, represent and R⁴ ′ is unsubstituted or C₁-C₁₂-alkyl-substituted alkylene with 1 to 18 C atoms and Y is O or S.

If the substituents R¹, R¹ ′, R², R³ or R⁵ are alkyl having 1 to 24 carbon atoms, these are, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, 2-butyl, t-butyl, pentyl, 1- Methylphenyl, isopentyl, hexyl, 1,3-dimethylbutyl, heptyl, 1,1,3,3-tetramethylbutyl, 1-methylhexyl, 3-heptyl, octyl, 2-ethylhexyl, 1-methylheptyl, nonyl, 1,1,3- Trimethylhexyl, decyl, undecyl, dodecyl, 1-methylundecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, eicosyl etc.

For the alkyl substituents R⁴ with 4 to 18 C atoms and R⁶ with 1 to 20 C atoms, the above examples apply mutatis mutandis to the respective C chain length.

wobei a eine Zahl von 3 bis 9 ist. Diese Cycloalkylgruppe kann gegebenenfalls durch C₁-C₄-Alkyl substituiert sein. Beispiele sind Cyclopentyl, Cyclohexyl, Methylcyclohexyl, Dimethylcyclohexyl, Trimethylcyclohexyl, t-Butylcyclo­hexyl, Cyclooctyl und Cyclododecyl.Means R¹ or R¹ 'cycloalkyl having 5 to 12 carbon atoms, it is about a group of the formula

where a is a number from 3 to 9. This cycloalkyl group can optionally be substituted by C₁-C₄-alkyl. Examples are cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, trimethylcyclohexyl, t-butylcyclohexyl, cyclooctyl and cyclododecyl.

The substituent phenyl- (C₁-C₄) alkyl is preferably benzyl.

Finally, R² or R³ can represent a phenyl substituted by C₁-C₁₂-alkyl. The examples of C₁-C₁₂ alkyl can be taken from the above list. Examples are methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl, t-butylphenyl, isopropylphenyl, di-t-butylphenyl or 2,6-di-t-butyl-4-methylphenyl.

R⁴ 'in formula (IIa) can mean unsubstituted or C₁-C₁₈ alkyl substituted alkylene. Examples include methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, decamethylene or dodecamethylene, furthermore di-1,1-dimethyl-2,2-dimethyldimethylene, 1,1,2-trimethyl-2- n-propyltrimethylene, 2-ethyl-2-n-butyltrimethylene, 1-iso-propyl-2,2-dimethyltrimethylene, 1-methyltrimethylene, 2,2-dimethyltrimethylene, 1,1,3-trimethylene or 2,2,4- or 2,4,4-trimethylhexamethylene. Preferably R⁴ 'represents dimethylene or trimethylene.

In an expedient embodiment, R¹ and R¹ 'are the same or different in the compounds of the formula I and are -H, alkyl having 4 to 12 carbon atoms, cycloalkyl and preferably cyclohexyl, or phenyl- (C₁-C₄) alkyl.

In a preferred embodiment, R¹ and R¹ 'represent -H or alkyl having 4 to 8 carbon atoms.

Mixtures of two or more compounds of the formula I can in particular also be used as compounds of the series A). For example, the reaction products can be used as compounds of series A) obtainable by the method according to EP-A-0 149 422 can be used. The reaction product produced by the process mentioned is preferably used as such. According to the method of this latter patent, diphenylamine is reacted with diisobutylene in the presence of a catalyst to form a liquid antioxidant composition such that the reaction of diphenylamine with an excess of diisobutylene is carried out in the presence of an active alumina catalyst such that the concentration of diisobutylene over the reaction period in the It is kept essentially constant that the reaction temperature is at least 160 ° C., that the reaction is carried out until the 4,4′-di-tert-octyldiphenylamine content, based on the reaction mass without catalyst, is below 30% by weight, preferably below 25% by weight and the diphenylamine content below 10% by weight, preferably below 5% by weight, that the catalyst and unreacted diisobutylene are removed and that the resulting liquid product is isolated. This process results in a liquid reaction mixture containing 4,4'-di-tert-ocytyldiphenylamine. This reaction mixture, comprising the compounds from the series A), is preferably used for the mixture together with the compounds from the series B), as mentioned.

• a) Diphenylamin,
• b) 4-Tert-butyldiphenylamin
• c) i) 4-Tert-octyldiphenylamin
• c) ii) 4,4′-Di-tert-butyldiphenylamin
• c) iii) 2,4,4′-Tris-tert-butyldiphenylamin
• d) i) 4-tert-butyl-4′-tert-octyldiphenylamin
• d) ii) 2,2′- oder 2,4′-Di-tert-octyldiphenylamin
• d) iii) 2,4-Di-tert-butyl-4′tert-octyldiphenylamin
• e) i) 4,4′-Di-tert-octyldiphenylamin
• e) ii) 2,4-Di-tert-octyl-4′-tert-butyldiphenylamin

Suitable mixtures of compounds of the formula I can contain, for example, in varying proportions:

• a) diphenylamine,
• b) 4-tert-butyldiphenylamine
• c) i) 4-tert-octyldiphenylamine
• c) ii) 4,4'-di-tert-butyldiphenylamine
• c) iii) 2,4,4'-tris-tert-butyldiphenylamine
• d) i) 4-tert-butyl-4'-tert-octyldiphenylamine
• d) ii) 2,2'- or 2,4'-di-tert-octyldiphenylamine
• d) iii) 2,4-di-tert-butyl-4'tert-octyldiphenylamine
• e) i) 4,4'-di-tert-octyldiphenylamine
• e) ii) 2,4-di-tert-octyl-4'-tert-butyldiphenylamine

• a) 1 bis 5 Gew.-% Diphenylamin
• b) 8 bis 18 Gew.-% 4-Tert-butyldiphenylamin
• c) 21 bis 31 Gew.-% einer oder mehrerer der verbindungen
  • i) 4-Tert-octyldiphenylamin
  • ii) 4,4′-Di-tert-butyldiphenylamin
  • iii) 2,4,4′-Tris-tert-butyldiphenylamin
• d) 20 bis 31 Gew.-% einer oder mehrerer der verbindungen
  • i) 4-Tert-butyl-4′-tert-octyldiphenylamin
  • ii) 2,2′- oder 2,4′-Di-tert-octyldiphenylamin
  • iii) 2,4-Di-tert-butyl-4′tert-octyldiphenylamin
    und
• e) 15 bis 29 Gew.-% der Verbindungen
  • i) 4,4′-Di-tert-octyldiphenylamin oder
  • i) 4,4′-Di-tert-octyldiphenylamin und
  • ii) 2,4-Di-tert-octyl-4′-tert-butyldiphenylamin.

The mixture of compounds of the series A) of the formula I preferably contains

• a) 1 to 5 wt .-% diphenylamine
• b) 8 to 18% by weight of 4-tert-butyldiphenylamine
• c) 21 to 31% by weight of one or more of the compounds
  • i) 4-tert-octyldiphenylamine
  • ii) 4,4'-di-tert-butyldiphenylamine
  • iii) 2,4,4'-tris-tert-butyldiphenylamine
• d) 20 to 31% by weight of one or more of the compounds
  • i) 4-tert-butyl-4'-tert-octyldiphenylamine
  • ii) 2,2'- or 2,4'-di-tert-octyldiphenylamine
  • iii) 2,4-di-tert-butyl-4'tert-octyldiphenylamine
    and
• e) 15 to 29% by weight of the compounds
  • i) 4,4'-di-tert-octyldiphenylamine or
  • i) 4,4'-di-tert-octyldiphenylamine and
  • ii) 2,4-di-tert-octyl-4'-tert-butyldiphenylamine.

This mixture can be obtained in particular by the process mentioned.

bedeutet,
wobei m = 1 und p = 0 oder 1 ist, oder m = 2 und p = 0 ist, und R⁴ die oben angegebene Bedeutung hat.In further expedient embodiments, the substituent R 2 in the formula II denotes -H, alkyl having 1 to 12 carbon atoms, phenyl, o-hydroxyphenyl, 3,5-di-R⁶-4-hydroxyphenyl, where R⁶ has the meaning given above, Furyl or

means
where m = 1 and p = 0 or 1, or m = 2 and p = 0, and R⁴ has the meaning given above.

wobei m = 1 und p = 0 oder 1 ist, oder m = 2 und p = 0 ist, und R⁴ die oben angegebene Bedeutung hat.R³ in formula II is suitably -H, alkyl having 1 to 12 carbon atoms or

where m = 1 and p = 0 or 1, or m = 2 and p = 0, and R⁴ has the meaning given above.

-OR⁵,

wobei R⁵ für Alkyl mit 1 bis 18 C-Atomen und vorzugsweise für Alkyl mit 8-13 C-Atomen und s für 1 oder 2 steht.In an expedient embodiment, R⁴ denotes alkyl having 4 to 12 carbon atoms, phenyl or - (CH₂)

-OR⁵,

where R⁵ is alkyl with 1 to 18 carbon atoms and preferably for alkyl with 8-13 carbon atoms and s is 1 or 2.

The substituents R⁴ are expediently the same in compounds of the formula II.

wobei R⁴ die eingangs angegebene Bedeutung hat, darstellt. R⁴ hat bevorzugt die Bedeutung von Alkyl mit 8 bis 12 C-Atomen oder -CH₂-

-OR⁵,

wobei R⁵ verzweigtes Alkyl mit 8 bis 13 C-Atomen und insbesondere Tert.-butyl oder 2-Ethylhexyl darstellt, ist.Finally, the very particularly preferred compounds of the formula II include those in which R² is -H, alkyl having 1 to 8 C atoms, furyl or phenyl, then compounds in which R³ -H, alkyl having 1 to 8 C atoms or

where R⁴ has the meaning given above. R⁴ preferably has the meaning of alkyl having 8 to 12 carbon atoms or -CH₂-

-OR⁵,

wherein R⁵ is branched alkyl having 8 to 13 carbon atoms and in particular tert-butyl or 2-ethylhexyl.

Compounds from series B) can be used as individual compounds or as a mixture of different compounds from series B) with one another in each case in a mixture with a compound from series A) or a mixture of compounds from series A).

As mentioned, the lubricant composition accordingly contains a mixture of at least one compound from the series A) with the formula I and at least one compound from the series B) with the formula II.

Mixtures of 1 to 9 parts by weight of the compound or compounds of series A) with 9 to 1 parts by weight of the compound or compounds of series B), and preferably of 2 to 8 parts by weight of the compound or compounds of series A) and 8, are expedient up to 2 parts by weight of the compound or the compounds of series B) applied.

eingesetzt.Mixtures containing, as compounds of series A), 3 parts by weight of a reaction mixture containing 4,4'-di-tert-octyldiphenylamine and, as compounds of series B), 7 parts by weight of the compound of the formula

used.

wobei i-C₈H₁₇ ein Gemisch von verzweigten Isomeren mit jeweils 8 C-Atomen bedeutet, in einem Mischungsverhältnis von A) zu B) von 9:1 bis 1:1 Gewichtsteilen. Insbesondere beträgt das Mischungsverhältnis von A) zu B) 9:1 oder 7:3 oder 1:1 Gewichtsteile.Mixtures are preferably also used, comprising as compounds of series A) a reaction mixture containing 4,4'-di-tert-octyldiphenylamine and as compounds of series B), a compound of the formula

where i-C₈H₁₇ is a mixture of branched isomers each having 8 carbon atoms, in a mixing ratio of A) to B) from 9: 1 to 1: 1 parts by weight. In particular, the mixing ratio of A) to B) is 9: 1 or 7: 3 or 1: 1 parts by weight.

wobei i-C₈H₁₇ ein Gemisch von verzweigten Isomeren mit jeweils 8 C-Atomen bedeutet, in einem Mischungsverhältnis von A) zu B) von 9:1 bis 1:9 Gewichtsteilen. Insbesondere beträgt das Mischungsverhältnis von A) zu B) 9:1 oder 3:7 oder 1:9 Gewichtsteile.A preferred mixture contains as compounds of series A) a reaction mixture containing 4,4'-di-tert-octyldiphenylamine and, as a compound of series B), a compound of the formula

where i-C₈H₁₇ is a mixture of branched isomers each having 8 carbon atoms, in a mixing ratio of A) to B) from 9: 1 to 1: 9 parts by weight. In particular, the mixing ratio of A) to B) is 9: 1 or 3: 7 or 1: 9 parts by weight.

wobei dieses Verfahren ohne Lösungsmittel oder in einem Lösungsmittel, z.B. in Cyclohexan, Toluol, Xylol oder Nitro- oder Chlorbenzol durchge­führt werden kann.

The compounds of formula II are for example from Reid, "Organic Chemistry of Bivalent Sulfur", vol. 3, pp. 320-341, Chemical Publishing Company, New York, 1960, and can be synthesized in a manner known per se. The following reaction routes are available, for example:

this method can be carried out without a solvent or in a solvent, for example in cyclohexane, toluene, xylene or nitro or chlorobenzene.

The process can be carried out either without the presence of a solvent or e.g. perform in methanol, ethanol, hexane or toluene as the solvent.

The mixture according to the invention is suitable for adding lubricants, in particular those based on mineral oils, synthetic oils or semi-synthetic lubricating oils and hydraulic fluids.

Mineral oils, synthetic and semi-synthetic lubricating oils, as well as their mixtures and hydraulic fluids, which expediently contain 0.1 to 10% by weight, e.g. 0.1 to 5 wt .-%, and preferably 0.1 to 1.0 wt .-%, each based on the lubricant or the hydraulic fluid, a mixture of at least one compound A) and at least one compound B), which desired properties, especially with regard to the good oxidation resistance.

The lubricants in question are described, for example, in "Ullmann's Encyclopedia of Technical Chemistry", vol. 13, pages 85-94 (Verlag Chemie, Weinheim, 1977), in D. Klamann, "Lubricants and Related Products", Verlag Chemie, Weinheim ( 1982) or in JH Schewe, W. Kobek, "The Lubricant Pocket Book", Hüthig Verlag, Heidelberg (1974), and familiar to the person skilled in the art.

The lubricant can thus be, for example, an oil based on a mineral oil or a synthetic oil, or a fat. The term mineral oil includes all mineral oils for lubrication purposes, such as hydrocarbon-based mineral oils. Synthetic oils can be, for example, aliphatic or aromatic carboxyl esters, polymeric esters, polyalkylene oxides, phosphoric acid esters, poly-α-olefins, silicones, glycols, polyglycols or polyalkylene glycols.

The lubricants can additionally contain other additives which are added in order to further improve the basic properties of lubricants; these include: other antioxidants, metal passivators, rust inhibitors, viscosity index improvers, pour point depressants, dispersants, detergents, thickeners, biocides, anti-foaming agents, demulsifiers and emulsifiers, as well as high-pressure additives and friction reducers.

Examples of phenolic antioxidants 1. Alkylated monophenols

2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-iso-butylphenol, 2,6-di-cyclopentyl4-methylphenol, 2- (α-methylcyclohexyl) - 4,6-dimethylphenol, 2,6-di-octadecyl-4-methylphenol, 2,4,6-tri-cyclohexylphenol, 2,6-di-tert-butyl-4-methoxymethylphenol, o-tert-butylphenol.

2. Alkylated hydroquinones

2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butyl-hydroquinone, 2,5-di-tert-amyl-hydroquinone, 2,6-diphenyl-4-octadecyloxyphenol.

3. Hydroxylated thiodiphenyl ether

2,2'-thio-bis- (6-tert-butyl-4-methylphenol), 2,2'-thio-bis- (4-octylphenol), 4,4'-thio-bis- (6-tert- butyl-3-methylphenol), 4,4'-thio-bis- (6-tert-butyl-2-methylphenol).

4. Alkylidene bisphenols

2,2'-methylene-bis- (6-tert-butyl-4-methylphenol), 2,2'-methylene-bis- (6-tert-butyl-4-ethylphenol), 2,2'-methylene-bis - [4-methyl-6- (α-methylcyclohexyl) phenol], 2,2'-methylene-bis- (4-methyl-6-cyclohexylphenol), 2,2'-methylene-bis- (6-nonyl- 4-methylphenol), 2,2'-methylene-bis- (4,6-di-tert-butylphenol), 2,2'-ethylidene-bis- (4,6-di-tert-butylphenol), 2,2 '-Ethylidene-bis- (6-tert-butyl-4-isobutylphenol), 2,2'-methylene-bis- [6- (α-methylbenzyl) -4-nonylphenol], 2,2'-methylene- bis- [6- (α, α-dimethylbenzyl) -4-nonylphenol], 4,4'-methylene-bis- (2,6-di-tert-butylphenol), 4,4'-methylene-bis- (6th tert-butyl-2-methylphenol), 1,1-bis (5-tert-butyl-4-hydroxy-2-methylphenyl) butane, 2,6-di- (3-tert-butyl-5-methyl) -2-hydroxybenzyl) -4-methylphenol, 1,1,3-tris- (5-tert-butyl-4-hydroxy-2-methylphenyl) -3-n-dodecyl mercaptobutane, ethylene glycol bis- [3,3-bis - (3'-tert-Butyl-4'-hydroxyphenyl) butyrate], bis- (3-tert-butyl-4-hydroxy-5-methylphenyl) dicyclopentadiene, bis- [2- (3'-tert-buty l-2'-hydroxy-5'-methylbenzyl) -6-tert-butyl-4methyl-phenyl] terephthalate.

5. Benzyl compounds

1,3,5-tri (3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, bis- (3,5-di-tert-butyl-4-hydroxybenzyl) - sulfide, isooctyl 3,5-di-tert-butyl-4-hydroxybenzyl-mercaptoacetic acid, bis- (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) -dithiol terephthalate, 1,3,5- Tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 3, 5-di-tert-butyl-4-hydroxybenzylphosphonic acid dioctadecyl ester, 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid monoethyl ester, calcium salt.

6. Acylamiophenols

4-hydroxy lauric anilide, 4-hydroxy stearic anilide, 2,4-bis-octylmercapto-6- (3,5-di-tert-butyl-4-hydroxyanilino) -s-triazine, N- (3,5-ditert -butyl-4-hydroxyphenyl) -carbamic acid octyl ester.

7. Esters of β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid with mono- or polyhydric alcohols, e.g. With

Methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol, neopentyl glycol, tris-hydroxyethyl isocyanurate, thiodiethylene glycol, bis-hydroxyethyl oxalic acid diamide.

8. Esters of β- (5-tert-butyl-4-hydroxy-3-methylphenyl) propionic acid with mono- or polyhydric alcohols, e.g. With

Methanol, diethylene glycol, octadecanol, triethylene glycol, 1,6-hexanediol, pentaerythritol, neopentyl glycol, tris-hydroxyethyl isocyanurate, thiodiethylene glycol, di-hydroxyethyl oxalic acid diamide.

9. Amides of β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid, e.g.

N, N'-bis (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) hexamethylene diamine, N, N'-bis (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) trimethylene diamine, N, N'-bis (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) hydrazine.

Examples of aminic antioxidants:

N, N'-di-isopropyl-p-phenylene diamine, N, N'-di-sec-butyl-p-phenylene diamine, N, N'-bis (1,4-dimethyl-pentyl) -p-phenylene diamine, N, N'-bis (1-ethyl-3-methyl-pentyl) -p-phenylenediamine, N, N'-bis (1-methyl-heptyl) -p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N , N'-di- (naphthyl-2) -p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, N- (1-methyl-heptyl) -N'-phenyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, 4- (p-toluenesulfonamido) diphenylamine, N, N'-dimethyl -N, N'-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxy-diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 4-n-butylaminophenol, 4-butyrylamino-phenol, 4-nonanoylamino-phenol, 4-dodecanoylamino-phenol, 4-octadecanoylamino-phenol, di- (4-methoxy-phenyl) -amine, 2,6-di-tert-butyl-4-dimethylamino- methyl-phenol, 2,4'-diamino-diphenylmethane, 4,4'-diamino-diphenylmethane, N, N, N ', N'-tetramethyl-4,4'-diamino-dip henylmathan, 1,2-di - [(2-methylphenyl) amino] ethane, 1,2-di (phenylamino) propane, (o-tolyl) biguanide, di- [4- (1 ′ , 3'-dimethyl-butyl) -phenyl) amine, tert-octylated N-phenyl-1-naphthylamine, mixture of mono- and dialkylated tert-butyl / tert-octyldiphenylamines, 2,3-dihydro-3,3-dimethyl -4H-1,4-benzothiazine, phenothiazine, N-allylphenothiazine.

Examples of other antioxidants

Aliphatic or aromatic phosphites, esters of thiodipropionic acid or thiodiacetic acid, or salts of dithiocarbamide or dithiophosphoric acid.

Examples of metal passivators are:

for copper, for example:
Triazoles, benzotriazoles and their derivatives, 2-mercaptobenzothiazole, 5,5'-methylenebisbenztriazole, 4,5,6,7-tetrahydrobenzetriazole, 2,5-di-mercaptothiadiazole, salicylidene-propylenediamine, salts of salicylaminoguanidine.

Examples of rust inhibitors are:

• a) Organic acids, their esters, metal salts and anhydrides, for example:
  N-oleoyl-sarcosine, sorbitan mono-oleate, lead naphthenate, dodecenylsuccinic anhydride, alkenylsuccinic acid half-ester, 4-nonylphenoxy-acetic acid.
• b) nitrogen-containing compounds, for example:
  • I. Primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic acids, for example oil-soluble alkylammonium carboxylates.
  • II. Heterocyclic compounds, for example:
    Substituted imidazolines and oxazolines.
• c) phosphorus-containing compounds, for example:
  Amine salts of phosphoric acid partial esters.
• d) sulfur-containing compounds, for example:
  Barium dinonylnaphthalene sulfonates, calcium petroleum sulfonates.

Examples of viscosity index improvers are:

Polyacrylates, polymethacrylates, vinyl pyrrolidone / methacrylate copolymers, polyvinyl pyrrolidones, polybutenes, olefin copolymers, styrene / acrylate copolymers, polyethers.

Examples of pour point low mixers are:

Polymethacrylate, alkylated naphthalene derivatives.

Examples of dispersants / surfactants are:

Polybutenylsuccinic acid imides, polybutenylphosphonic acid derivatives, basic magnesium, calcium and barium sulfonates and phenolates.

Examples of wear protection additives are:

Compounds containing sulfur and / or phosphorus and / or halogen, such as sulfurized vegetable oils, zinc dialkyldithiophosphates, tritolyl phosphate, chlorinated paraffins, alkyl and aryl disulfides, triphenylphosphorothionates, diethanolaminomethyltolyltriazole and di (2-isooctyl) aminomethyltolyl.

The invention also encompasses the use of mixtures of compounds of series B) as an antioxidant in lubricants and hydraulic fluids.

The additives according to the invention are also effective in lubrication systems of the type described above, but which additionally have a co-lubrication system which contains customary amounts of solid lubricants, such as graphite, boron nitride, molybdenum disulfide or polytetrafluoroethylene.

The compounds of the series A) and the compounds of the series B) can be mixed with one another in the proportions indicated and the mixture can then be mixed in with the lubricant or the hydraulic fluid in the quantities mentioned. It is also expedient to mix the compounds of the series A) and the compounds of the series B) separately with the lubricant or the hydraulic fluid, the quantitative proportions given also having to be adhered to in this case. The production of so-called masterbatches is also possible.

The invention is further explained with the aid of the following examples.

Unless otherwise stated, all parts and percentages are by weight.

Example 1: a) Preparation of the thioketal component

106.1 g of benzaldehyde and 408.7 g of 2-ethylhexyl thioglycolic acid in 100 ml of toluene are introduced, 10 g of bleaching earth (Tonsil L 80 S®) are added and the gray suspension is boiled on a water separator. After 45 minutes of refluxing, water is split off and the suspension turns pink. After 4 hours, about 17 ml of water (18 ml according to theory) split off. The mixture is allowed to cool to ∼80 ° C and the pink colored suspension is filtered off and washed with a little toluene. The clear gold-yellow filtrate is on a rotary evaporator at about 20 torr. concentrated and then dried at 70 ° C under a high vacuum 0.02 Torr.

= 1,518. Analyse: gefunden: 65,22 % C, 9,01 % H, 12,81 % S berechnet: 65,28 % C 8,93 % H, 12,91 % S, 12,88 % O 487.6 g, equal to 98.15% of theory, of a golden yellow oily liquid are obtained. n $\genfrac{}{}{0ex}{}{\text{20th}}{\text{D}}$

= 1.518. Analysis: found: 65.22% C, 9.01% H, 12.81% S calculated: 65.28% C 8.93% H, 12.91% S, 12.88% O

b) Preparation of the reaction mixture containing 4,4'-di-tert-octyldiphenylamine:

169.2 g of diphenylamine and 33.8 g of active alumina (Fulcat® 22B from Laporte Industries) are placed in a reaction vessel provided with a stirrer and temperature sensor and heated to 165 ° C. As soon as the mixture is sufficiently liquid, the mixture is stirred. Then 196.4 g of diisobutylene are gradually metered in, so that the temperature of the reaction mixture does not drop below 165 ° C. The addition takes 5 hours to complete the reaction. The reflux begins immediately after the start of the reaction. The heating and stirring is continued at 165 ° C, under frequent sampling until the gas / liquid chromatography analysis shows a content of 4,4'-di-tert-octyldiphenylamine of less than 25% by weight (without catalyst).

The reaction mass is cooled to 60 ° C. and the catalyst is removed by vacuum filtration. The filtrate is transferred to a distillation apparatus and the pressure is reduced to 26 mbar with heating and stirring.

During the distillation, the outside temperature is allowed to rise slowly to 165 ° C. and is kept constant at this temperature for 2 hours while the distillation comes to a standstill. 300 g of a viscous, dark liquid with a flash point of 210 ° C. are obtained.

The liquid has the approximate composition of 3.2% by weight diphenylamine, 13.2% by weight 4-tert-butyldiphenylamine, 25.3% by weight of compounds from the 4-tert-octyldiphenylamine series, 4.4 '-Di-tert-butylamine and 2,4,4'-tris-tert-butylamine, 24.2% by weight of compounds from the series 4-tert-butyl-4'-tert-octyldiphenylamine, 2.2' - or 2,4'-di-tert-octyldiphenylamine and 2,4-di-tert-butyl-4'tert-octyldiphenylamine and 18.2% by weight of 4,4'-di-tert-octyldiphenylamine and 6.0 Wt .-% 2,4-di-tert-octyl-4'-tert-butyldiphenylamine, as well as further shares in other higher alkylated diphenylamines with modified side chains and polymers.

The thioketal compound according to a) and the reaction mixture according to b) are mixed with one another in the amounts evident from example 4. These latter mixtures are mixed in an amount of 0.25% by weight, based on the oil, of a mineral oil of the Mobil 15 SS4 type.

Example 2:

• a) A thioketal component of the general formula
  
  where i-C₈H₁₇ stands for a mixture of branched isomers, is prepared analogously to Example 1a).
• b) The reaction mixture containing 4,4'-di-tert-octyldiphenylamine is prepared according to Example 1b).

The thioketal compound according to a) and the reaction mixture according to b) are mixed with one another in the amounts evident from example 4. These latter mixtures are mixed in an amount of 0.25% by weight, based on the oil, of a mineral oil of the Mobil 15 SS4 type.

Example 3:

• a) A thioketal component of the general formula
  
  is produced analogously to example la).
• b) The reaction mixture containing 4,4'-di-tert-octyldiphenylamine is prepared according to Example 1b).

The compounds according to a) and the reaction mixture according to b) are combined in the proportions from a) to b) of 9: 1, 7: 3, 1: 1, 3: 7 and 1: 9 parts by weight and processed into corresponding mixtures.

Example 4: Application of the components in a lubricant composition TOST-TEST , oxidation characteristics of mineral oil (ASTM D934 / DIN 51587 / IP 157)

The oil to be tested (Mobil 15 SS4) is heated to 95 ° C. in the presence of water, oxygen, an iron-copper catalyst and the stabilizer for 1000 hours. The TAN acid value (in mg KOH consumption per g test oil) and the sludge (SLUDGE) (in mg residue per batch) are then determined. The results are summarized in Table 1. The concentration of the stabilizer mixtures is 0.25% by weight, based on the oil. Table 1 Example 4 Stabilizer (total 0.25% by weight) mixture of 1000 hours TOST % By weight according to the example % By weight according to the example TAN (mg KOH / g oil) SLUDGE (mg) a) 30 1a) 70 1b) 0.21 61 b) 70 1a) 30 1b) 0.21 49 c) 10 2a) 90 2b) 0.35 22 d) 30 2a) 70 2b) 0.28 32 e) 50 2a) 50 2b) 0.26 71 f) without without > 2nd > 1000 (Comparison)

Table 2 below shows the measured values from the TOST test for various mixtures of compounds according to Example 3. The test procedure and conditions are given above, except for the test duration which is 500 hours and the oil (mineral oil BB). Table 2 Example 4 Stabilizer (total 0.25% by weight) mixture of 500 hours TOST % By weight according to the example % By weight according to the example TAN (mg KOH / g oil) SLUDGE (mg) G) 10 3a) 90 3b) 0.24 58 H) 30 3a) 70 3b) 0.25 38 i) 50 3a) 50 3b) 0.11 14 k) 70 3a) 30 3b) 0.08 27th l) 90 3a) 10 3b) 0.08 87

Claims (18)

1. Composition containing at least one lubricant or a hydraulic fluid and a mixture of one or more compounds from the series A) and one or more compounds from the series B), the compounds of the series A) having the general formula

have in which R¹ and R¹ 'are the same or different and -H, alkyl having 1 to 24 carbon atoms, cycloalkyl having 5 to 12 carbon atoms or phenyl- (C₁-C₄) alkyl and n is a number from 0 , 1 or 2 means and the compounds of series B) the general formula

have in which R² -H, alkyl having 1 to 24 carbon atoms, phenyl, substituted with NO₂, Cl, Br, F, C₁-C₁₂-alkyl and / or C₁-C₁₂-alkoxy phenyl, phenyl- (C₁-C₄ ) alkyl, phenyl of the general formula

wherein R⁶ is -H, alkyl having 1 to 20 carbon atoms or phenyl- (C₁-C₄) alkyl and x is 1 or 2, or R₂ is furyl, tetrahydrofuryl, 2-methylfuryl, 2-methyltetrahydrofuryl, cyclohexyl or is unsubstituted or methyl-substituted cyclohexenyl or R² is a group of the formula

stands, where m = 1 and p = 0 or 1, or m = 2 and p = 0, and R⁴ has the meaning given below and R³ -H, alkyl having 1 to 24 carbon atoms, phenyl, with NO₂, Cl, Br, F or C₁-C₁₂ alkyl substituted phenyl, phenyl- (C₁-C₄) alkyl or a phenyl radical of the general formula

means where R⁶ and x have the meaning given or R³

where m = 1 and p = 0 or 1, or m = 2 and p = 0, or

means, where R⁴ each has the meaning given below, or R₂ and R₃ together represent a -CH₂- (CH₂) ₂₋₉-CH₂ group and the radicals R⁴ are identical or different and alkyl having 4 to 18 carbon atoms, phenyl , Tolyl, benzyl or - (CH₂)

-OR⁵,

where s = 1 or 2 and R⁵ is alkyl having 1 to 24 carbon atoms, and R⁴ 'is unsubstituted or C₁-C₁₂-alkyl-substituted alkylene having 1 to 18 carbon atoms and Y is O or S. 2. Composition according to claim 1, wherein the substituents R¹ and R¹ 'in formula I are the same or different and are -H, -alkyl having 4 to 12 carbon atoms, cycloalkyl having 5 to 8 carbon atoms. 3. Composition according to claim 2, wherein R¹ and R¹ 'are cyclohexyl or phenyl- (C₁-C₄) alkyl. 4. The composition of claim 2, wherein R¹ and R¹ 'represent -H or alkyl having 4 to 8 carbon atoms. 5. The composition of claim 1, wherein the compounds of the series A) with the general formula I containing a mixture
a) 1 to 5 wt .-% diphenylamine
b) 8 to 18% by weight of 4-tert-butyldiphenylamine
c) 21 to 31% by weight of one or more of the compounds
i) 4-tert-octyldiphenylamine
ii) 4,4'-di-tert-butyldiphenylamine
iii) 2,4,4'-tris-tert-butyldiphenylamine
d) 20 to 31% by weight of one or more of the compounds
i) 4-tert-butyl-4'-tert-octyldiphenylamine
ii) 2,2'- or 2,4'-di-tert-octyldiphenylamine
iii) 2,4-di-tert-butyl-4'tert-octyldiphenylamine
and
e) 15 to 29% by weight of the compounds
i) 4,4'-di-tert-octyldiphenylamine
or
i) 4,4'-di-tert-octyldiphenylamine and
ii) 2,4-di-tert-octyl-4'-tert-butyldiphenylamine,
represent. 6. The composition according to claim 1, wherein R² -H, alkyl having 1 to 12 carbon atoms, phenyl, o-hydroxyphenyl, 3,5-di-R⁶-4-hydroxyphenyl, where R⁶ has the meaning given in claim 1, furyl or

means
where m = 1 and p = 1 or m = 2 and p = 0, and R⁴ has the meaning given in claim 1. 7. The composition according to claim 1, wherein R³ -H, alkyl having 1 to 12 carbon atoms,

where m = 1 and p = 0 or 1, or m = 2 and p = 0, and R⁴ has the meaning given in claim 1. 8. The composition according to claim 1, wherein R⁴ alkyl having 4 to 12 carbon atoms, phenyl or - (CH₂)

-OR⁵,

where R⁵
represents alkyl having 1 to 18 carbon atoms and preferably alkyl having 1-13 carbon atoms and s represents 1 or 2, and the substituents R⁴ in formula II are each the same. 9. The composition according to claim 1, wherein the substituent R² is -H, alkyl having 1 to 8 carbon atoms, furyl or phenyl. 10. The composition according to claim 1, wherein R³ -H, alkyl having 1 to 8 carbon atoms or

wherein R⁴ has the meaning given in claim 1. 11. The composition according to claim 8, wherein R⁴ alkyl having 8 to 12 carbon atoms or -CH₂-

-OR⁵ is

where R⁵ represents branched alkyl having 8 to 13 carbon atoms. 12. The composition of claim 11, wherein R⁵ is tert-butyl or 2-ethylhexyl. 13. The composition according to claim 1, comprising a mixture of 1 to 9 parts by weight of at least one of the compounds from the series A) and 9 to 1 part by weight of at least one of the compounds from the series B). 14. The composition according to claim 1, containing a mixture of, as compounds from the series A), a reaction mixture containing 4,4'-di-tert-octyldiphenylamine and, as a compound of the series B), a compound of the formula

the mixing ratio of A) to B) is 3: 7 or 7: 3 parts by weight. 15. The composition according to claim 1, containing a mixture of, as compounds of series A), a reaction mixture containing 4,4'-ditert-octyl-diphenylamine and, as compounds of series B), a compound of formula

where i-C₈H₁₇ is a mixture of branched isomers each having 8 carbon atoms and the mixing ratio of A) to B) is 9: 1 to 1: 1 parts by weight. 16. The composition according to claim 1, containing a mixture of, as a compound of series A), a reaction mixture containing 4,4'-di-tert-octyl-diphenylamine and, as a compound of series B) a compound of formula

where i-C₈H₁₇ is a mixture of branched isomers each having 8 carbon atoms, in a mixing ratio of A) to B) from 9: 1 to 1: 9 parts by weight. 17. The composition of claim 1, containing 0.1 to 10 wt .-%, based on the lubricant or the hydraulic fluid, a mixture of at least one compound of the series A) and at least one compound of the series B). 18. Use of mixtures of compounds of the series A) and compounds of the series B) according to claim 1 as an antioxidant in lubricants and hydraulic fluids.