DE2756488A1 - LUBRICANT ADDITIVES - Google Patents

Description

The present invention relates to dithiophosphate derivatives, their use as lubricant additives, and the lubricating oil formulations equipped with the new compounds.

Various additives are generally added to mineral and synthetic lubricants to improve their performance properties. In particular, there is a need for additives which are intended to protect the devices to be lubricated from frictional wear. Such wear inhibitors are required to meet the load Increase the load-bearing capacity of the lubricant and do not have a corrosive effect on the metal parts to be protected. It is known from SU patent 295,791 to use N-mono-substituted dithiophosphate acetic acid amide lubricating oil additives. N-disubstituted dithiophosphate acetic acid amides are known as pesticides from GB patent 1,255,946.

It has now surprisingly been found that the dithiophosphates of the formula I are superior to the known high-pressure additives for lubricants, in particular with regard to freedom from ashes, thermal stability, non-corrosiveness to iron and non-ferrous metals and resistance to hydrolysis.

The invention accordingly relates

Dithiophosphate lubricant additives of the formula I

I,

wherein

R [deep] 1 and R [deep] 2 independently of one another are C [deep] 3 -C [deep] 12 alkyl, which is optionally interrupted by 1 or 2 O atoms, C [deep] 6 -C [deep] 10 Aryl or (C [deep] 1 -C [deep] 12 alkyl) -aryl, or R [deep] 1 and R [deep] 2 together mean C [deep] 2 -C [deep] 12 alkylene, optionally through 1 or 2 O atoms is interrupted, and

X -OH, -NR [deep] 3 R [deep] 4, -OH times NR [deep] 3 R [deep] 4 R [deep] 5, -NHCH [deep] 2 COOH, -NHCH [deep] 2 COOR [deep] 1, -N (CH [deep] 2 COOH) [deep] 2, -N (CH [deep] 2 COOR [deep] 1) [deep] 2, -N (CH [deep] 2 COOH) [ deep] 2 times NR [deep] 3 R [deep] 4 R [deep] 5, -N (CH [deep] 2 COOH times NR [deep] 3 R [deep] 4 R [deep] 5) [deep] 2 , -NHCH [deep] 2 OH or -N (CH [deep] 2 CH [deep] 2 OH) [deep] 2, wherein

R [deep] 3, R [deep] 4 and R [deep] 5 are independently hydrogen or C [deep] 1 -C [deep] 18 alkyl, or R [deep] 3 and R [deep] 4 together are C [ deep] 3 -C [deep] 12 are alkylene, which is optionally interrupted by an O, S or N atom.

Alkyl R [deep] 1 and R [deep] 2 is straight-chain or branched alkyl with 3-12 C atoms, such as n-propyl, i-propyl, n-butyl, i-butyl, sec. Butyl, amyl, neopentyl, Hexyl, 1-methylpentyl, n-octyl, i-octyl, t-octyl, 2-ethyl-hexyl, n-decyl, 2-ethyl-decyl and n-dodecyl.

Alkyl R [deep] 1 and R [deep] 2 interrupted by 1 or 2 O atoms is straight-chain or branched alkyl of this type with 3-12 C atoms, in particular alkoxyalkyl with a total of 3-12 C atoms, such as 2-methoxyethyl, 2-ethoxyethyl, 2-n-propoxyethyl, 2-i-propoxyethyl, 2-n-butoxyethyl and 2-n-octoxyethyl.

If R [deep] 1 and R [deep] 2 together form alkylene with 2-12 C atoms, this is straight-chain or branched, in particular optionally mono- or multiply C [deep] 1 -C [deep] 4 -alkylated ethylene or propylene -1,3, especially mono- or polymethylated-1,3-propylene, such as ethylene, 1,3-propylene, 1,4-butylene, 2-methylpropylene-1,3, 2,2-dimethylpropylene-1,3 and 1,1,3-trimethylpropylene-1,3.

Aryl R [deep] 1 and R [deep] 2 is in particular phenyl, alkylaryl in particular two-, three- or in particular simply C [deep] 1 -C [deep] 12 -alkylated phenyl, especially C [deep] 1 -C [deep] 4-alkylated phenyl, such as methylphenyl or isopropylphenyl.

Alkyl R [deep] 3, R [deep] 4 and R [deep] 5 is, in addition to that specified for R [deep] 1, also methyl or ethyl or C [deep] 13 -C [deep] 18 alkyl, such as n-octadecyl .

R [deep] 3 and R [deep] 4 together as C [deep] 3 -C [deep] 12 alkylene is in particular optionally mono- or polyalkylated, such as C [deep] 1 -C [deep] 4 alkylated, in particular methylated 1,4-butylene or 1,5-pentylene, such as in particular 1,4-butylene or 1,5-pentylene itself. If such an alkylene is interrupted by an O, S or N atom, it is together with the R [deep] 3 / R [deep] 4 bonding N atom, in particular around morpholino, thiomorpholino, piperazino or 4-methylpiperazino.

Dithiophosphates of the formula I are particularly suitable in which

R [deep] 1 equals R [deep] 2 and C [deep] 3 -C [deep] 8 alkyl, or R [deep] 1 and R [deep] 2 together C [deep] 2 -C [deep] 8 Are alkylene, and

X -NR [deep] 3 R [deep] 4, -OH or -OH times NR [deep] 3 R [deep] 4 R [deep] 5 is wherein

R [deep] 3, R [deep] 4 and R [deep] 5 are independently hydrogen or C [deep] 1 -C [deep] 18 alkyl.

Above all, dithiophosphates of the formula I are preferred in which

R [deep] 1 equals R [deep] 2 and C [deep] 3 -C [deep] 8 alkyl, or R [deep] 1 and R [deep] 2 together C [deep] 2 -C [deep] 8 Are alkylene,

X is -NR [deep] 3 R [deep] 4, and

R [deep] 3 is R [deep] 4 and C [deep] 1 -C [deep] 18 is alkyl.

Above all, the dithiophosphates mentioned in the examples are preferred.

The new compounds of the formula I are prepared by processes known per se. This is done either in accordance with GB patent 1,255,946 and compounds of the formula I where X is -NR [deep] 3 R [deep] 4 is obtained, or an acid (R [deep] 1 O) (R [ deep] 2 O) P (S) -S-CH [deep] 2 -COOH with an amine NR [deep] 3 R [deep] 4 R [deep] 5 µm and obtains compounds of the formula I where X is equal to -OH times NR [deep] 3 R [deep] 4 R [deep] 5. But you can also react a dithiophosphoric acid ester with an appropriately substituted chloroacetamide, such as with the disodium salt of N, N-bis-carboxymethyl-chloroacetamide.

Even in very small amounts, the compounds of the formula I act as high-pressure additives in lubricants. Mineral and synthetic lubricating oils and mixtures thereof, for example, contain 0.001 to 5% by weight, based on the lubricant, and preferably 0.02 to 3% of a compound of the formula I are equipped with excellent high-pressure lubrication properties, which are evident from the greatly reduced signs of wear and tear on the friction partners to be lubricated. The lubricants in question are familiar to the person skilled in the art and are described, for example, in the "Lubricant Pocket Book" (Hüthig Verlag, Heidelberg, 1974).

The lubricating oil formulation can additionally contain other additives which are added in order to improve certain performance properties, such as antioxidants, metal passivators, rust inhibitors, viscosity index improvers, pour point depressants, dispersants / detergents and other anti-wear additives.

Examples of antioxidants are:

a) Alkylated and non-alkylated aromatic amines and mixtures thereof, e.g .:

Dioctyldiphenylamine, mono-t-octylphenyl-small alpha and small beta-naphtylamine, phenotriazine, dioctylphenothiazine, phenyl-small alpha-naphthylamine, N, N´-di-sec.-butyl-p-phenylenediamine.

b) Sterically hindered phenols, e.g. 2,6-di-tert-butyl-p-cresol, 4,4´-bis- (2,6-diisopropylphenol), 2,4,6-triisopropylphenol, 2,2´- Thio-bis- (4-methyl-6-tert-butyl-phenol), 4,4'-methylene-bis- (2,6-di-tert-butylphenol).

c) alkyl, aryl or alkaryl phosphites, e.g .:

Trinonyl phosphite, triphenyl phosphite, diphenyl decyl phosphite. d) esters of thiodipropionic acid or thiodiacetic acid, e.g .:

Dilauryl thiodipropionate or dioctyl thiodiacetate.

e) Salts of carbamic and dithiophosphoric acids, e.g .:

Antimony diamyldithiocarbamate, zinc diamyldithiophosphate.

f) Combination of two or more antioxidants of the above, e.g .:

an alkylated amine and a hindered phenol.

Examples of metal passivators are:

a) for copper, e.g. benzotriazole, tetrahydrobenzotriazole, 2-mercaptobenzotriazole, 2,5-dimercaptothiadiazole, salicylidene-propylenediamine, salts of salicylaminoguanidine.

b) for lead, e.g. sebacic acid derivatives, quinizarin, propyl gallate,

c) Combination of two or more of the above additives.

Examples of rust inhibitors are:

a) Organic acids, their esters, metal salts and anhydrides, e.g .:

N-oleoyl sarcosine, sorbitan mono-oleate, lead naphthenate, dodecenyl succinic anhydride. b) Nitrogen-containing compounds, e.g .:

I. Primary, secondary or tertiary aliphatic or cycloaliphatic amines and amine salts of organic and inorganic acids, e.g., oil-soluble alkylammonium carboxylates.

II. Heterocyclic compounds e.g .:

Substituted imidazolines and oxazolines.

c) Phosphorus-containing compounds e.g .:

Amine salts of phosphoric acid partial esters,

d) Sulfur-containing compounds e.g .:

Barium dinonylnaphthalene sulfonate, calcium petroleum sulfonate,

e) combinations of two or more of the above additives.

Examples of viscosity index improvers are e.g .:

Polymethacrylates, vinyl pyrrolidone / methacrylate copolymers, polybutenes, olefin copolymers, styrene / aerylate copolymers.

Examples of pour point depressants are e.g .:

Polymethacrylates, alkylated naphthalene derivatives.

Examples of dispersants / detergents are e.g .:

Polybutenylsuccinic acid imides, polybutenylphosphonic acid derivatives, overbased magnesium, calcium and barium sulfonates and phenates.

Examples of other anti-wear additives are e.g .:

Compounds containing sulfur and / or phosphorus and / or halogen, such as sulfurized vegetable oils, zinc dialkyldithiophosphates, tritolyl phosphate, chlorinated paraffins, alkyl and aryl disulfides.

The following examples illustrate the invention.

example 1

83.2 g (0.33 mol) of potassium salt of O, O-di-isopropyl-dithiophosphoric acid are suspended in 200 ml of acetone and, with stirring, with a solution of 53.3 g (0.3 mol) of chloroacetic acid-N, N- diisopropylamide in 200 ml of acetone, added. The mixture is then stirred for twelve hours at room temperature, the precipitated potassium chloride is filtered off, the filtrate is concentrated completely and the oily residue is taken up in toluene. After washing three times with water, the organic phase is concentrated to dryness under reduced pressure.

This gives the O, O-di-isopropyl-S- (N, N-diisopropyl-carbonamidomethyl) dithiophosphate with a melting point of about 30 ° C. (additive 1).

If the potassium salt of O, O-di-isopropyl-dithiophosphoric acid or the chloroacetic acid-N, N-diisopropylamide or both are replaced in Example 1 by the corresponding homologues listed in Table 1, the corresponding O, O- Dialkyl-S- (N, N-dialkylcarbonamidomethyl) -dithiophosphate:

Table 1

Table 1 continued Table 1 continued Table 1 continued Table 1 continued

Example 2

80 g (0.31 mol) of potassium salt or O, O-di-isopropyl-dithiophosphoric acid are dissolved in 100 ml of water and, while stirring, with a solution of 36.1 g (0.31 mol) of sodium salt of chloroacetic acid in 100 ml of water, offset. After stirring for 10 hours at room temperature, the reaction mixture is acidified with 50 ml of 6N hydrochloric acid and then extracted with 200 ml of toluene. The toluene phase is washed twice with water and then completely concentrated under reduced pressure. The O, O-di-isopropyl-S-carboxymethyl-dithiophosphate is thus obtained as a pale yellow oil.

If in this example 2 the potassium salt of O, O-di-isopropyl-dithiophosphoric acid is replaced by the potassium salt of O, O-diisobutyl or O, O-di-n-butyl or O, O- Diisoctyl-dithiophosphoric acid, the corresponding S-carboxymethyl-dithiophosphates are obtained as pale yellow oils with otherwise the same procedure. O, O-di-isooctyl-S-carboxymethyl dithiophosphate is additive # 41.

Example 3

5.12 g (0.02 mol) of O, O-di-isopropyl-S-carboxymethyl dithiophosphate are dissolved in 50 ml of toluene and mixed with 3.8 g (0.02 mol) of Primene 81R (mixture of primary C [deep]) 12 -C [deep] 15 t.Alkylamine, Röhm and Haas, USA) added with stirring. The solvent is completely distilled off under reduced pressure. This gives a yellowish, transparent oil that is easily soluble in hexane or mineral oil (additive no. 24).

If the O, O-di-isopropyl-S-carboxymethyl-dithiophosphate or Primene 81R or both are replaced in Example 3 by the corresponding homologues listed in Table 2, the corresponding ammonium salts are obtained with otherwise the same procedure:

Table 2

Table 2 continued

Example 4

25.4 g (0.1 mol) of the disodium salt of N, N-bis-carboxymethyl-chloroacetamide are placed in 100 ml of dimethylacetamide together with 4 g (0.1 mol) of sodium hydroxide and added dropwise with 21.4 g (0 , 1 mol) of di-thiophosphoric acid-O, O-diisopropyl ester are added and the mixture is stirred at room temperature for 12 hours. Then 17 ml of hydrochloric acid are concentrated and the reaction mixture is poured into 1500 ml of water. After extraction with chloroform, the organic phase is completely evaporated. The O, O-di-isopropyl-S - [(N, N-bis-carboxymethyl) -carbamoylmethyl] -di-thio-phosphoric acid ester is thus obtained as a yellowish oil.

Example 5

If, in Example 4, the di-thio-phosphoric acid O, O-di-isopropyl ester is replaced by an equimolar amount of di-thiophosphoric acid O, O-di-isooctyl ester, the isooctyl homologue is also obtained as a yellowish oil (additive No. 30).

Example 6

15.5 g (0.04 mol) of O, O-di-isopropyl-S - [(N, N-bis-carboxymethyl) -carbamoylmethyl] -di-thiophosphoric acid ester are dissolved in 100 ml of toluene and mixed with 9.7 g (0.04 mol) of di-isooctylamine are added. The solvent is completely distilled off under reduced pressure. This gives a reddish-yellow oil that is easily soluble in hexane or mineral oil (additive no. 39).

Example 7

In Example 6, the O, O-diisopropyl ester is replaced by an equimolar amount of the corresponding diisooctyl ester and the diisooctylamine by an equimolar amount of Primene 81-R (mixture of primary C [deep] 12 -C [deep] 15 t-alkylamines, Rohm and Haas) , USA), the corresponding ammonia is obtained as a yellowish oil (additive no. 40) with otherwise the same procedure.

Example 8

If the amount of Primene 81-R is doubled in Example 7, the di-ammonium salt (additive no. 41) is obtained with otherwise the same procedure.

Example 9

The extraordinary load-bearing properties of the lubricant additives according to the invention are also shown in the test in the FZG gear tension test bench.

For this purpose, mixtures of the additives according to the invention in a non-alloyed mineral lubricating oil (viscosity: 20 cSt / 50 ° C.) were prepared and tested with the FZG machine according to DIN 51354 (normal test A / 8.3 / 90). For comparison, the non-alloyed mineral lubricating oil without additives was also tested with the FZG machine.

The results of these investigations are compiled in Table 3 below.

Table 3

Example 10

The following values were determined with the Shell four-ball apparatus: (Tentative method IP 239/69, Extense pressure and wear lubricant test for oils and greases, four ball machine).

1) I.S.L. = Initial Seizure Load: This is the load at which the oil film collapses within a load period of 10 seconds.

2) W.L. = Weld Load. This is the load at which the 4 balls weld together within 10 seconds.

3) W.S.D. = Wear Scar Diameter in mm: This is the mean wear diameter with a load of 70 kg or 40 kg for 1 hour.

Catenex 41 (trade name of Shell) was used as the base oil.

Table 4

Table 4 (continued)

Claims (7)

1. Dithiophosphate lubricant additives of the formula I I, wherein R [deep] 1 and R [deep] 2 independently of one another are C [deep] 3 -C [deep] 12 alkyl, which is optionally interrupted by 1 or 2 O atoms, C [deep] 6 -C [deep] 10 Aryl or (C [deep] 1 -C [deep] 12 alkyl) -aryl, or R [deep] 1 and R [deep] 2 together mean C [deep] 2 -C [deep] 12 alkylene, optionally through 1 or 2 O atoms is interrupted, and X -OH, -NR [deep] 3 R [deep] 4, -OH times NR [deep] 3 R [deep] 4 R [deep] 5, -NHCH [deep] 2 COOH, -NHCH [deep] 2 COOR [deep] 1, -NH (CH [deep] 2 COOH) [deep] 2, -N (CH [deep] 2 COOR [deep] 1) [deep] 2, -N (CH [deep] 2 COOH) [ deep] 2 times NR [deep] 3 R [deep] 4 R [deep] 5, -N (CH [deep] 2 COOH times NR [deep] 3 R [deep] 4 R [deep] 5) [deep] 2 , -NHCH [deep] 2 OH or -N (CH [deep] 2 CH [deep] 2 OH) [deep] 2, wherein R [deep] 3, R [deep] 4 and R [deep] 5 are independently hydrogen or C [deep] 1 -C [deep] 18 alkyl, or R [deep] 3 and R [deep] 4 together are C [ deep] 3 -C [deep] 12 are alkylene, which is optionally interrupted by an O, S or N atom. 2. Lubricant additives according to claim 1, wherein R [deep] 1 equals R [deep] 2 and C [deep] 3 -C [deep] 8 alkyl, or R [deep] 1 and R [deep] 2 together C [deep] 2 -C [deep] 8 Are alkylene, and X is -OH, -NR [deep] 3 R [deep] 4 or -OH times NR [deep] 3 R [deep] 4 R [deep] 5, wherein R [deep] 3, R [deep] 4 and R [deep] 5 are independently hydrogen or C [deep] 1 -C [deep] 18 alkyl. 3. Lubricant additives according to claim 1, wherein R [deep] 1 equals 2 and C [deep] 3 -C [deep] 8 alkyl, or R [deep] 1 and R [deep] 2 together are C [deep] 2 -C [deep] 8 alkylene, X is -NR [deep] 3 R [deep] 4, and R [deep] 3 is R [deep] 4 and C [deep] 1 -C [deep] 18 is alkyl. 4. Lubricant additives according to claim 1, containing O, O-di-isopropyl-S- (N, N-diisopropyl-carbonamidomethyl) dithiophosphate. 5. Lubricant additives according to claim 1, containing the dithiophosphates mentioned in the examples. 6. Use of dithiophosphates according to any one of claims 1-5 as a lubricant additive. 7. Lubricant containing a dithiophosphate according to any one of claims 1-5.