DE2253962A1 - LUBRICATING OIL PREPARATIONS AND ANTIOXIDIZING AGENTS FOR THIS - Google Patents

Description

PATENT LAWYERS '^

8 MUNICH 8O. MAUERKIRCHERSTR. 43

Dr. Berg Dipl.-Ing. Stapf, 8 Munich 80, Mouerkircherstraße 45

_{Your reference} your letter Our ^{reference Dalum} - |. NOV. 1972

Attorney file 22 992
Be / Ro

Bsso Research and Engineering Company Linden / USA

"Lubricating Oil Preparations and Antioxidants Therefor"

This invention relates to lubricating oil formulations containing antioxidants.

So far, various antioxidant systems have been used for Lubricating oils, e.g. for aircraft lubrication, are suggested. It became sulfur-free antioxidants found that in addition to good antioxidant properties

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488272 <988272> 487043 (987043) 483310 <983310> telegrams! BERGSTAPF PATENT Munich TELEX 05 24 560 BERG d Banki Bayerische Vereinsbank Munich 453100 Postscheck! Some 653 43

have a low tendency to corrosiveness. These antioxidants further impart a synthetic ester lubricant a lower viscosity compared to the previously used naphthylamine derivatives, such as N- (p-octylphenyl) -ß-naphthylamine.

The present invention therefore relates to a lubricant preparation with the content of a larger part by weight of a lubricating oil and a smaller part by weight of one N-alkyl-N-phenyl ~ naphthylamine, the alkyl group of which has 1 to 10 carbon atoms and none of which has the nitrogen atom Has adjacent branch.

In a preferred embodiment of the invention that is Antioxidant a combination of the predefined N-alkyl-N-phenyl-naphthylamine and an N-phenylnaphthylamine. The presence of this further component leads to good antioxidant properties, but with less Tendency to thicken the base oil when added, compared to the previously used antioxidants.

The tertiary amine, i.e. the N-alkyl-N-phenyl-naphthylamine preferably has the general formula

, 2

ι 2

where E is hydrogen or an alkyl group and R is hydrogen or an O ₁ - Og -alkyl group. It is therefore

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it is preferred that the laphthylamine portion of the molecule be unsubstituted and that only one substituent (R) is present at most on the phenyl group. However, others can as well Substituents may be present, with hydrocarbyl substituents preferred over halogen or nitro substituents are.

It is further preferred that the laphthylamin.ein ß-naphthylamine, and in particular that, when R is a Is alkyl group, this is in the para position. The preferred tertiary amines therefore have the general one formula

When R is an alkyl group, this preferably contains 4-12 carbon atoms, and is for example t-butyl, n-pentyl, n-hexyl, t-octyl, iso-decyl or n-dodecyl

ρ
The group R is preferably hydrogen or a Cj - G ^ -alkyl group, for example methyl, ethyl or n-propyl

The particularly preferred tertiary amine is 1-methyl-N-N- (t-octylphenyl) -ß-naphthylamine, however, other very suitable tertiary amines l-methyl-l) I- (t-butylphenyl) -ß-naphthylamine), N-ethyl-N- (t-o ctylphenyl) ~ ß-naphthylamine or N-ethyl-N ~ (t-butylphenyl) -ß-naphthylamine are *

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When the secondary amine, i.e. the N-phenylnaphthylamine is present, this preferably has the general formula

3
where R is hydrogen or an alkyl group.

In the case of the tertiary amines, it is preferred that they only one substituent (R) at most on the phenyl or Have naphthyl parts of the molecule. It will continue preferred that the secondary amine is an or- or ß-naphthyl-

3 is amine, and particularly preferred that when R is a Is alkyl group, this is in the para position. The preferred secondary amines therefore have the general one formula

When R is an alkyl group, this preferably contains 4-12 carbon atoms, e.g. t-butyl, n-pentyl, iso-hexyl, n-heptly, n-nonyl or iso-dodecyl. If both

1 3
R and R, are alkyl groups (which is more likely than both being hydrogen atoms or just one residue of an alkyl group) it is preferred that in the antioxidant combination the total number of carbon atoms in R and

R is not more than 20 »

A particularly preferred secondary amine is N- (t-octyl-

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phenyl) -ß-naphthylamine, although other suitable Amines N- (t-butylphenyl) -ß-naphthylamine and N (t-octylphenyl) -ot-naphthylamine belong.

If the antioxidant, both the secondary and also contains tertiary amine, the weight ratio is from secondary to tertiary amine preferably between 3: 1 and 1 * 3 »e.g. at about 1: 1»

If the antioxidant (DCH. Either the tertiary amine alone or the tertiary amine plus the secondary amine) is added to the lubricating oil, so it should be the smaller portion, preferably 0.001 to 10 GewojS, z ₀ B "0.1 to 5 weight" $ based on the weight of the lubricating oil.

The lubricating oil to which the antioxidant mixture is added may be any mineral oil, animal oil, fish oil, vegetable oil or synthetic oil, for example petroleum fractions from fuels to spindle oil to lubricating * oil SAE 30, 40 or 50, castor oil, animal or liso oils or oxidized mineral oil, e.g. palm oil, fatty oil, tallow oil, peanut oil or sperm oil.

The preferred lubricating oil is a synthetic ester and suitable diesters include diesters of the general formula

ROOOR ¹ OOOR and RCiOOR ¹ OOCH and where R is an O ₆ to 0, ₂ -alkyl group, while R ₁

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a G ₄ to G ₁₀ saturated aliphatic hydrocarbon group or an 'ether-interrupted saturated aliphatic hydrocarbon group. The types of esters mentioned above can be prepared from alcohols and dicarboxylic acids or glycols and monocarboxylic acids.

Another suitable type of ester lubricant are polyesters, which are made by mixing polyvalent Alcohols, such as having 2 to 12 hydroxyl groups per molecule and having 2 to 40 carbon atoms per molecule Molecule, such as trimethylolpropane, pentaerythritol and dipentaerythritol with mono- and / or dicarboxylic acid, such as butyric acid, Caprylic acid and pelargonic acid or with adipic | Sebazine or Azelaic acids.

The complex esters that are used as base oils are by esterification reactions between a dioarboxylic acid, a glycol and an alcohol and / or a monooarboxylic acid manufactured. These esters have the following general formulas;

R ₄ COO-E ₃ - (00CR ₂ OOO-H ₃ ) _n -00CR ₄

R ₁ -OOCR ₂ COO- (R ₃ -OOCr ₂ COO) ₁₁ -R ₁ R ₁ - (COCR ₂ COO-R ₃ ) _n 00CR ₄

wherein R-. alkyl radicals derived from a monohydric alcohol, R ₂ hydrocarbon radicals derived from a dicarboxylic acid, for example from alkanedioic acids, R ₃ divalent hydrocarbon or hydrocarbonoxy radicals, such as

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-CH ₂ (CH ₂ ) _n - or -GH ₂ OH ₂ (OGH ₂ OH ₂ ) _n - or ₃ (00H ₂ OH (OH ₅ )) _n -, which are derived from an alkylene glycol or polyalkylene glycol, while E, is an alkyl group derived from a monocarboxylic acid, "n" in the complex ester molecule is an integer, usually from 1 to 6, depending on the desired viscosity of the product, this being controlled by the relative molar ratio of the glycol or polyglycol to the dicarboxylic acid will. In the preparation of the complex esters, some simple esters are always formed, ie where η = 0, but this is generally a small proportion. In general, these complex esters have a total of 15 to 80, for example 20 to 65, carbon atoms per molecule.

Particularly suitable lubricants are esters of polyhydric alcohols of the general formula

OH ₂ OH

EO-OH ₀ OH
I ^ά

OH ₂ OH

where E is a —CH ₂ OH group or an alkyl group, for example an alkyl group with 1 to 6 carbon atoms. Suitable esters of this type are the leopentyl polyol esters of trimethylolethane, trimethylolpropane, trimethylolbutane and of pentaerythritol or dipentaerythritol.

The preferred acids that are used to esterify trimethylolpropane are the 0 to 0 ^ ₂ mono-carboxylic acids

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- ο -

Ren. Particularly preferred among the C ₇ -C ₁₀ acid esters are the Cg (caprylic) and Cq (pelargonic) acid esters. Mixtures of these C ₇ -C ₁ 2 ~ acids can be used. When using such an acidic mixture, it is preferred that the mixture average between Cg and Cq. Although more difficult to manufacture, it is particularly preferred that a methylol group with a neo-heptanoic acid, e.g. 2 »2-dimethylpentanoic acid is esterified, and the remaining methylol groups with non-hindered acids, such as pelargonic acid, are esterified. This particular ester is as overall and thermally stable as the fully hindered esters, but has lower volatility and poorer low temperature properties.

The preferred acids which are used for the esterification of pentaerythritol are the C.-C.I., monocarboxylic acids, the particularly preferred esters being those of C.sub.1 to C.sub.6 acids, for example n-valeric, isovaleric, 2 -Ethylbutter, caproone, n-heptyl, n-octanoic or 2-ethylhexonic acids or a mixture of Cr to C _n acids.

0 y

Mixtures of diesters with minor proportions of one or more thickening agents can also be used as lubricants. So you can use mixtures that up to 50 vol. fo one or more water-insoluble polyoxyalkylene glycols, for example polyethylene or polypropylene glycol or mixed oxyethylene / oxypropylene glycols.

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Formulations suitable for Gasturbinensehmierung, include those having a content of from 65 "to 90 VoI" fi of one or more diesters of azelaic acid or sebacic acid and a Og - 0-g branched chain alcohol, mainly 2-ethylhexanol or "oxo" -Alcohols, which predominantly consist of Gg-, Gq- or C ^ -alcohols "or mixtures of such alcohols, and 35 to 10 $ polyoxyalkylene glycol ethers of the general formula:

RO

CH-O

in which the radicals R 1, R and R _{2 are} hydrogen or Cj to GJ ₂ -alkyl groups, and in which no more than two such groups are hydrogen and η is an integer greater than 1. Particularly valuable compounds are polyoxypropylene glycol monoethers and the corresponding dieters.

The thermal stability of such diesters / polyoxyalkylene glycol ethers can be improved by incorporating a small proportion of a complex ester derived from three or more carboxylic acids or alcohols, at least two of which are difunctional acids or alcohols. Such complex esters can be glycol- or dicarboxylic acid-centered, the molecule having a monohydroxy or monocarboxylic acid compound at the end. A particularly preferred complex ester of this type is derived from Poly- 309833/0758 _ ₁₀ -

Ethylene glycol with a molecular weight of 200, 2 molecules of sebacic or azelaic acid and 2 molecules of a Cg to O ₁₀ branched-chain aliphatic monohydric alcohol, especially 2-ethylhexanol.

For other additives that are incorporated into the lubricating oil preparation corrosion inhibitors such as sebacic acid, a metal deactivator such as quinizarine Foam inhibitor, e.g. silicone polymer such as dirnethyl silicone or a slip-improving additive, e.g. neutral alkyl phosphates such as tricresyl phosphate, neutral aryl phosphates or neutral phosphonates.

example 1

N-methyl-NCp-t-octyl-phenylJ-ß-naphthylamine (MOPBNA) and N (p-t-octyl-phenyl) -β-naphthylamine (OPBNA) were separated and added together at various concentrations to a synthetic ester lubricant which is a mixture of esters was obtained by esterification of 90? έ pentaerythritol and 10 $ dipentaerythritol with a mixture of (Cg - C.q) fatty acids were obtained. The base oil also contained 1.0% by weight tricresyl phosphate.

The mixtures of oil plus antioxidant were subjected to the Rolls-Royce Oxidation Test (R-R 1001) with the results are given in Table 1 below

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Table 1

Ge antioxidant volatility induc- KV TAN benzene mixture dations-. TION 210 Wfo Unlös Central time (hr.) Ii before s jo

+ 2fo
. Mon MOPBNA
OPBNA
MOPBNA
OPBNA 192 hours at 215 ° 0 109
180
92 ' 3.87
4.78
3.9. 0.01
0.05
0.02 A.
B.
O 37.8
42.0
32.0 78
• 48
96 2 <fo MOPBNA
OPBNA 72 hours at 215 ° 0 126
149 5.72
4.5 0.00
0.01 D.
E. 30.5
31.6 24
24

It should be noted that the mixture A is longer Induction time than one has from the sum of the induction times of Mixtures D and E could expect.

Example 2

The kinematic viscosities of different base oils mixed with different antioxidants were shown were set. The base oil I was a mixture of 80 parts by weight of pentaerythritol and 10 parts by weight of dipentaerythritol and 10 parts by weight of trimethylolpropane, esterified with a mixture of O ^ - O ^ -monocarboxylic acids. The basic Oil II was the same as the base oil used in Example 1. The results are shown in Table 2 below remove.

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Table 2

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Table 2 KV58 (cS) KV-40 (cS) Antioxidant
medium weight $ KV99 (cS) Base oil I. 26.64 8,987 3.0 $ OPBNA 5.10 26.5 8.030 ^ _t 5fo OPBNA +
1,5Ji MOPBNA 5.06 Base oil II 28.3 > 9,000 2 # OPBNA 5.26 26.87 7,952 $ 2 MOPBNA 5.16 28.6 79,500 3 # OPBNA 5.35 - - 3 # MOPBNA 5.14

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Claims : -13-

Claims (10)

Claims $ 1. Labeled lubricant preparation duroh a larger weight fraction of lubricating oil and a smaller one Weight fraction of li-alkyl-IT-phenyl-naphthylamine, its Alkyl group has 1 to 10 carbon atoms and none has branches adjacent to the nitrogen atom » 2. Sohmiermittelzubereitung according to claim 1, characterized ₉ that the U-alkyl-N-phenyl-naphthylamine the formula 1 2 has, wherein R is hydrogen or an alkyl group, R Is hydrogen or a CL - Og -alkyl group, preferably where R is an alkyl group and is in the para position · 3. Preparation according to one of the preceding claims ^; daduroh characterized that the naphthylamine is beta-naphthylamine, 4. Preparation according to one of claims 2 and 5, characterized in that B is a -14-309833 / 0758 an alkyl group with 4 Ma 12 carbon atoms and R Is hydrogen or an O- - CU-alkyl group. 5. Preparation according to claim 1, characterized that the naphthylamine Nr methyl-N- (t-octyl) -ß-naphthylamine is. 6. Preparation according to one of the preceding claims. d. a characterized by that they continue Contains N-phenyl-naphthylamine, which is preferably the formula corresponds to where R is hydrogen or an alkyl group. 7. Preparation according to claim 6, characterized that R is an alkyl group in the para position, preferably an alkyl group with 4 to 12 carbon atoms is. 8. Preparation according to claim 4 and 7, characterized that the total number of carbon atoms in the groups R and R is not more than 20. 9. Preparation according to one of claims 6 to 8, characterized in that the weight ratio of N-alkyl-N-phenyl-naphthylamine to N-phenylnaphthylamine is between 3: 1 and 1: 3. -15-309833 / 0758 10. Preparation according to one of the preceding claims characterized in that the lubricating oil is a synthetic ester, preferably a polyester which is produced by reacting a polyhydric alcohol with a mono- and / or dicarboxylic acid «. 309833/0758