DE2228352A1 - Stabilized lubricants - Google Patents

Description

Stabilized lubricants

The invention relates to stabilized lubricants, and more particularly to ester lubricants stabilized against oxidation.

Synthetic ester lubricants are increasingly used as high temperature lubricants, because in In connection with the development of jet drives operating at high temperatures, increasingly synthetic ones Lubricants based on organic diesters, such as the diesters of adipic acid, azelaic acid or sebacic acid be used with Cg to C ^ alcohols. Particularly Di- (2-ethylhexyl) sebacate, for example, is often used as a lubricating oil for jet engines and in similar lubricants. However, the ever increasing demand has led to numerous diesters in recent times

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other more widely available dicarboxylic acids can be used.

Synthetic lubricants are frequently added to about 0.5 wt.% Of phenothiazine as an oxidation stabilizer. However, even then, these lubricant mixtures have not proven to be completely satisfactory at high temperatures because, due to rapid decomposition, they lead to undesirable changes in viscosity, excessive sludge formation, increased corrosion and similar undesirable side effects. A particular disadvantage is that these lubricants generally do not meet the high requirements required of oxidation stability.

The invention is therefore based on the object of providing lubricants, in particular ester lubricants, with increased To develop storage stability and improved oxidation stability at high temperatures.

To achieve the object, ester lubricants are proposed which are characterized in that they contain a smaller amount of a secondary N, N-diaromatic as an oxidation stabilizer (A) Amine or a tertiary N, N-diaromatic N-aralkylamine and (B) a minor amount of an N-substituted one Phenothiazines of the general formula

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Contained, in which R is a substituent of the general

Formulas'

or

in which η is zero or an integer from 1 to ¹ J, R ₅ and Rg are hydrogen atoms or a methyl group and can be identical or different, and in which A, B, D, E, F, G and J are each hydrogen atoms or an amino, halogen, nitro, hydroxy, CL- to CL ₂ -AIkOXy- or CL- to CL _? -Alkyl group, where these substituents can be identical or different,

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provided that at least one of the substituents is not a hydrogen atom, and in the FL, R-, R- * and Rj, may be identical or different and each represent a hydrogen atom, an alkyl, alkoxy or aralkyl group with up to 12 carbon atoms, provided that at least one of these substituents is a CL- to CLp-alkyl or Is alkoxy group.

In the description and in the claims are under halogen substituents fluorine, chlorine or bromine atoms and under "minor amount" amounts on the order of about 0.1 part by weight per 100 parts by weight of the ester lubricating oil Understood.

The lubricants according to the invention have good storage stability and improved oxidation resistance high temperatures of e.g. 120 to 230 C or even higher. The lubricating oils according to the invention lead to those treated therewith Parts to an extended service life, a reduced abrasion and a substantially reduced one

, ^, Corrosion.
ο

qo As ester lubricating oils, all suitable for lubricating purposes can be used or

* ° Carboxylic acid esters can be used, such as, for example, aliphatic diesters of the general formula R ₇ OOC (CHp) COORg, in which η is a

ca and R8

• p * integer from 2 to 3 ^ and R ₇ 'each an even or

branched-chain alkyl group, phenoxyalkyl or alkyloxyalkyl group with 6 to 20 carbon atoms. It is preferred to use compounds in which η in the general formula is an integer from * 1 to 8 and R _{7 and R} g are even

or branched-chain alkyl groups with 8 to 16 carbon atoms mean. Such compounds are e.g. di- (2-ethylhexyl) sebacate, di- (2-ethylhexyl) azelate, diisodecyl sebacate, diisooctyl azelate, Isooctyl isodecyl adipate or di- (1,3-dimethylbutyl) adipate.

The ester oils can also be esters of aliphatic monocarboxylic acids with polyols such as aliphatic alcohols with 2 or contain more hydroxyl groups. The acids suitable for preparing these esters are, for example, aliphatic acids with 3 to 18 and preferably 4 to 12 carbon atoms; suitable polyols are e.g. trimethylolpropane, neopentyl glycol, Pentaerythritol, dipentaerythritol or mixtures thereof. Esters of this type are e.g. pentaerythrityl tetrabutyrate, Pentaerythrityl tetracaproate, pentaerythrityl dibutyrate dicaproate, mixed esters of pentaerythritol with saturated Cj, - to CL -fatty acids, mixed hexaesters des Dipentaerythritol with C ^ - to C ^ Q-fatty acids or Trimethylolpropane tricaprylate.

The ester oils can also be aliphatic polyesters of the general formula

0 0 0 0

I I II 11

Rq-O-C-R ^ -Q C-0-R-Tj-O-C-R ^ Q-C-O-Rq

contain, in which R «is an alkyl group with i to 12

and preferably 5 to 12 carbon atoms in a branched one Chain means, which refers to the oxygen atom

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ß-carbon atom is preferably a tertiary carbon atom, and in which R _{10 is} an alkylene group with 6 to 20 carbon atoms in a straight or branched chain and R ^ _{1 is} an alkylene or oxyalkylene group with 2 to 20 C atoms. Such polyesters can be prepared, for example, by esterifying 2 moles of an aliphatic dicarboxylic acid with one mole of glycol and then esterifying this diester with 2 moles of a monoalcohol per mole of the diester.

If appropriate, mixtures of such carboxylic acid esters can also be used as ester oils.

That according to the invention used as an oxidation stabilizer Amine A can be used as a secondary N, N-diaromatic amine, i.e. with two with the nitrogen atom of the amino group linked aromatic substituents are present. As aromatic substituents can be heterocyclic or carbocyclic substituents occur, compounds with carbocyclic benzene or alkyl substituted Benzene groups are preferred. Optionally can also be used as secondary aromatic Amines in the benzofused rings substituted phenothiazines or phenothiazine derivatives are used. In general, however, compounds are preferred in which the two aromatic rings of the amine only linked through the nitrogen atom of the amino group. The aromatic substituents of the amine can be the same

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or be different; suitable secondary aromatic Amines are e.g. N-phenyl-1-naphthylamine, diphenylamine, N-phenyl-2-naphthylamine, their mixtures or their alkyl or alkoxy substituted derivatives. Preference is given to using compounds in which at least one of the aromatic rings has alkyl or alkoxy substituents, such as N-phenyl- (l-octyl) -2-naphthylamine or N- (II-octyl) phenyl-1-naphthylamine. The 'alkyl substituents can have ^ to 12 and preferably θ carbon atoms. A particularly preferred compound is di- (p-octylphenyl) amine, especially the isomer Di- (p- (2,2,3,3-tetramethyl-butyl) -phenyl) -amine.

As amine component A, together with or instead of secondary Ν, Ν-diaromatic amine also uses a tertiary N, N-diaromatic N-aralkylamine in particular tertiary amines in which the aralkyl group (RO the general formulas I, II or III can have:

(D

E D

(ID

D B

(III)

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in which η, R, -, Rg, A, B, D, E, F, G and J are the ones already can have given meanings, except that A, B, D, E, P, G, and J can all be hydrogen atoms. as The halogen substituent is preferably a bromine or chlorine atom. These tertiary amines show one unexpected increased effectiveness in terms of oxidation stability and prevention of sludge formation together with the N-substituted phenothiazines Bj this increase in effectiveness is in comparison to the use of the individual Connections extraordinarily high and completely surprising. Those with the nitrogen atom of the tertiary Amine-linked aromatic substituents are preferably a first aromatic substituent Alkyl or alkoxy-substituted phenyl group and as the second aromatic substituent a phenyl, alkyl or alkoxy-substituted phenyl, 1-naphthyl, 2-naphthyl or alkyl or alkoxy substituted 2-naphthyl group. The alkyl groups of the first and second aromatic substituents can have 1 to 12 and preferably 8 carbon atoms; preferred are compounds in which this alkyl group of the aromatic is an octyl group and in particular an Means 2,2,3,3-tetramethylbutyl group.

Suitable tertiary amines correspond to the general formulas

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or

in which R. is an aralkyl group of the general formulas

I, II or III,

' ^R

22> ^R 2V

^{And R}

25th

identical or different substituents, namely hydrogen atoms, C ^ - to C ₁₂ ~ alkyl groups or C ^ - to C ^ p -alkoxy groups, provided that at least one of these substituents is not a hydrogen atom, and in which R «g and Rp _{7 are} identical or mean different Cj to C ₁₂ alkyl groups or C ^ to Cp alkoxy groups. In preferred compounds used in the alkyl group is an octyl group, and ⁴ in particular a 2,2,3,3-tetramethylbutyl group. Particularly suitable tertiary amines are compounds of the general formula

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OH, CH ₃

in the R ₂ g a -CHp- CC CH, group

CH ₃ CH ₃

and R. are an aralkyl group as defined above. If appropriate, mixtures can also be used such tertiary amines can be used.

Preference is given to N, N-bis-i "- (2, 2, 3,3-tetramethylbutyl) phenyl-benzylamine and N, N-bis-4- (2,2,3> 3-tetramethylbutyl) -2-phenylethylamine used, with a particularly high oxidation stability and a reduction in sludge formation when these compounds are used together with N- (2,4-dichlorobenzyl) -3,7-di- (2 _s 2,3,3-tetramethylbutyl) phenothiazine or N - (3, M-dichlorobenzyl) -3,7-di- (2,2,3,3-tetramethylbutyl) -phenothiazine can be used. These tertiary amines suitable as oxidation stabilizers can be prepared, for example, according to the processes described in the patent application filed on the same day in accordance with US Pat. No. 1,523,72.

The amine component A is added to the ester lubricating oils in small amounts such as from 0.5 to 8 and preferably from 1 to ¹ parts by weight per 100 parts by weight of the ester.

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The N-substituted phenothiazines B used according to the invention are mostly compounds in which the nitrogen substituent is an aralkyl group with 7 to 22 carbon atoms in the alkyl group, the aromatic ring being replaced by at least one halogen, nitro, alkyl, alkoxy, amino - or hydroxyl group is substituted. The alkyl and alkoxy groups preferably contain 1 to 12 carbon atoms; preferred halogen substituents are fluorine, bromine or chlorine atoms. In general, particularly good stability improvements are achieved if A, B, D, E, F, G and J in the general formula of the phenothiazines each have hydrogen atoms or amino, chlorine, bromine, nitro, hydroxy or C ₁ bis C 1-4 alkoxy groups, provided that at least one of these substituents is not a hydrogen atom. Suitable substituents are, for example, 2,4-pichlorobenzyl-3, M-diehlobenzyl, 2- (tI-chlorophenyl) ethyl, 2,4-pibromobenzyl, 3> ^ - dibromobenzyl, 4-nitrobenzyl, 4-hydroxy -benzyl or IJ-butoxybenzyl groups.

In addition, at least one of the substituents R ₁ , R ₂ * Ri or R ^ in the formula of the N-substituted phenothiazines _{should preferably be a C 1} - to C ₁ ^ - alkyl or alkoxy group; particularly preferred

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are compounds which contain two such straight or branched chain octyl groups, which can be located on the same or on both fused benzene rings. Suitable N-substituted phenothiazines are, for example, N- (2, i | -Dichlorobenzyl) -3,7-dioctyl-phenothiazine and N- (3, i »-dichlorobenzyl) -3,7-dioctyl-phenothiazine, where R ₂ and R , Octyl groups such as 2,2,3,3-tetramethylbutyl groups and R ₁ and R ^ are hydrogen atoms.

The N-substituted phenothiazines B are used together with the amine component A to improve the oxidation stability of ester oils, the N-substituted ones Phenothiazines B used in smaller amounts of usually 0.5 'to 10 and preferably from 0.5 to 3 parts by weight per 100 parts by weight of the ester oil will.

In general, the N-substituted phenothiazines can be prepared by reacting phenothiazine or ■ a derivative substituted on the core with sodium hydride in the presence of dimethyl sulfoxide, wherein

as an intermediate product, the sodium salt of the used Forms phenothiazine. This intermediate is then substituted with an appropriate aralkyl chloride

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reacted further to form the N-substituted phenothiazine.

The representation of N- (3, * l-dichlorobenzyl) -3,7-dioctylphenothiazine can e.g. be represented by the following reaction equation:

(H ₁₇ C ₈

(H ₁₇ C ₈ ).

(C ₈ H ₁₇ )

+ H,

(3,7-dioctyl-phenothiazine)

CH ₂ Cl

Cl

(H ₁₇ C ₈

(C ₈ H ₁₇ )

Cl

(N- (3, ¹ I-DiChIo ^ eHZyI) -3.7 · dioctyl-phenothiazine)

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These methods of preparation for N-substituted phenothiazines are filed in on the same day Patent application according to US S.N. 152 372, it being noted that tertiary Amines such as N-substituted phenothiazines can be obtained in better yield and higher purity if Phenothiazine compounds or, in general, aromatic secondary amines only after the conversion of sodium hydride be added with dimethyl sulfoxide.

The preparation of N- (3, ⁱ <-Dichlorbenzyl) -3,7- (2,2,3,3-tetramethylbutyl) -phenothiazine can be carried out, for example, as follows: 1.5 mol of dimethyl sulfoxide are poured into a 3-liter Filled in the flask with reflux condenser, stirrer, nitrogen inlet tube, thermometer and dropping funnel. The dimethyl sulfoxide is ^{heated to about 60 °} C. and then 1.1 mol of a 60 % strength by weight sodium hydride dispersion in mineral oil is added while stirring. In general, the reaction mixture turns light orange with the evolution of hydrogen; the mixture is stirred for a further 1/2 hour after the evolution of hydrogen has commenced. Then 1 mol of 3> 7- (2,2,3,3-tetramethyl- _/ butyl) -phenothiazine is added with further stirring, the reaction mixture, if necessary, being cooled so that the temperature remains below 100.degree. The reaction mixture is stirred for about 2 hours and then 1 mol of 3,1J-dichlorobenzyl chloride is added dropwise with further stirring. The mixture will turn, if necessary

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cooled so that the temperature of the mixture is about 90 to 100 ° C. After stirring for 6 hours, 200 ml of water are added dropwise, a viscous oil separating out in the reaction mixture. The oily phase is extracted by shaking with Ί00 ml of toluene and, if necessary, washed several times with 200 ml of aqueous 10 wt. To remove residual solvent and volatile compounds in the oil medium strong vacuum is heated to 150 ⁰ C and resulting, after cooling, N- (3,4-Dichlorbenzy1) -3,7 (2,2,3,3-tetramethylbuty1) -phenothiazine .

The preparation of other N-substituted phenothiazines can be carried out in a corresponding manner.

The lubricating oils stabilized according to the invention can also contain triazoles or substituted triazoles as metal deactivators, such as 3-Amino-1,2,1-triazole, 1,2-amino-1,2,11-triazole, 1,2,3-benzotriazole and alkyl-substituted compounds such as 5-methyl-1,2,3-benzotriazole or 5,5'-methylene-bis- (1,2,3-benzotriazole). The triazoles are added according to their solubility, usually the content of triazoles is up to about 1, often about 0.002 to 0.2 and preferably about 0.01 to 0.2 parts by weight per 100 parts by weight of the ester oil.

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In addition, the ester lubricants of the present invention can contain phosphorous containing esters such as e.g. Triester of phosphoric acid with aliphatic straight or branched chain alcohols with 1 to 8 carbon atoms such as triethyl phosphate, tributyl phosphate or triisooctyl phosphate. Other suitable phosphoric acid esters are, for example, esters of phenol or naphthol, which can have 1 to 3 alkyl groups with 1 to 10 carbon atoms in the aryl substituents, such as tricresyl phosphate or triphenyl phosphate. In general, triaryl phosphates are preferably used, however, phosphorothionates, such as triphenyl phosphorothionate, can optionally also be added. the Phosphorus-containing acid esters are usually used in amounts up to 10 parts by weight and preferably from 0.5 to 5 parts by weight per 100 parts by weight of the ester oil were added.

The lubricants according to the invention can optionally be used also metal deactivators, corrosion inhibitors, rust inhibitors, foam inhibitors, Contains colorants, thickeners, other antioxidants and additives common in ester lubricants.

The lubricants according to the invention can be applied in a simple manner only to those to be lubricated Surfaces are applied, namely in places where the surfaces of two parts are relative to each other move under friction, so that through the

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Lubricant prevents the surfaces from rubbing will. If appropriate, the lubricants according to the invention can also be used in such a way that they adhere to circulate around the lubrication points so that the lubricants heated by friction flow away from the lubrication point and cooled lubricant flows back into the lubrication point. Around a circulating lubricant system To enable various suitable devices known per se can be used.

The invention is explained in more detail below with reference to the examples. Unless otherwise stated, refer to all partial information is based on weight.

Example 1 - 11

The quantities given in Table I were converted into lubricating oils by homogeneously mixing the constituents produced, the lubricating oils from Examples 1-6 containing either phenothiazine or 3,7-dioctyl-phenothiazine. These compounds have already been proposed for improving the oxidation stability of ester oils been. In Examples 7-10 the according to the invention Mixtures used. The lubricating oil from Example 11 did not contain a phenothiazine compound and served as Control.

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209853 / 1 2 3 Table I. and weight • 7th 8th 9 10 11 I. O Isooctyl isodecyl adipate 100 100 100 5 . Parts 100 100 100 100 100 Tricresyl phosphate 1 1 1 Example no. 100 6th 1 1 1 1 1 2.0 Phenothiazine. 0.5 0.5 0.5 1 100 --- o.o; 3,7-dioctylphenothiazine (1)
N- (2,4-dichlorobenzyl) -
3,7-dioctyl-phenothia
interest (2) 100 1 1.5 - O N- (3, ^ - dichlorobenzyl) -
3,7-dioctyl-phenothia-
interest (3) _{wm mla mm} 1 1.0 0.5 ... 1.5 1.5 1.5 RIG Di (p-octylphenyl) amine 2.0 2.0. 0.5 ^ W IB 2.0 2.0 2.0 2.0 >
r ~
Tt 3-Amino-l, 2, ² l-triazole 0.05 2.0 0.05 0.05 m ^ -Amino-l ^ j ^ -triazole _ "_ ___ a> W * 0.05 2.0 —_— ___ 0.05 ίο 4.0 —_— "Fo". (1), (2), (3) The Octy! Groups thou 0.05 0.05 5-tetramethy! Butyl groups 8352 ___ 2,2,3,3 Connections were

These lubricating oils were designed for corrosion and Oxidation stability tested by placing small blocks of the specified metals, measuring 0.08 cm χ 2.5 cm χ 2.5 cm were placed in glass cylinders and covered with 100 ml of the lubricating oils.

The samples were then heated to and maintained at substantially 175 ° C. Purch dry, clean air was blown through the samples from below in quantities of 5 liters per hour; after a

After bubbling through the air for 72 hours, the metal blocks were removed from the lubricating oils with 1.1, 1.7 trichloroethane washed, air dried and weighed. As metals

Magnesium, aluminum, iron, copper and electrolytically pure silver were used in this experiment. the Changes in metal weights before and after

Test, expressed as mg / cm of metal surface, are compiled for the various lubricating oils in Table II.

Furthermore, the kinematic viscosity of the various lubricating oils before and after that described above Test measured according to the method of ASTM Standard D, and the results as a percentage increase the viscosity listed in Table II. This table also shows the changes in the acid number according to the procedure of ASTM D 664 included, whereby the

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Acid numbers by potentiometric titration with potassium hydroxide up to a final pH value of 11 according to the procedures of ASTM Standard D 66 * 1 were carried out. After completing the 72-hour oxidation-corrosion test the sludge formation was evaluated, with partly no sludge formation and partly slight, massive and heavy sludge formation was observed.

The lubricants according to the invention from Examples 7-10 show no sludge formation and thus show improved oxidation resistance and lower corrosiveness compared to the lubricating oils from the Examples 1-6 with a content of phenothiazine or the lubricating oil from Example 11 without phenothiazine compounds. In comparison to the lubricating oil from Example 5 with a content of 3,7-dioetyl-phenothiazine, the lubricating oils according to the invention have at least the same or better oxidation resistance.

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Table II

Lubricating oil
example Change in metal weight in mg / cm (1) Mg Al Fe Cu Ag Increase in
Acid number (2) Viscosity increase
in % at 38 ^° C mud
education K), 031
MD, 023
-0.046
-0.031
»■ 0.010
«. C.
N. G.
-0.015
K), 023
K>, 015
-0.015 +0.023
-0.023
-0.054
-0.015
+0.015
+0.010
NC
-0.010
+0.031
-0.021
-0.010 +0.031
+0.015
-0.015
-0.031
+0.015
+0.023
+0.015
+0.010
+ O, o23
+0.015
+0.010 +0.054
-1.123
-0.046
-0.046
+0.023
-0.023
-0.031
-0.015
-0.015
-0.015
-0.023 +0.062
NC
-0.039
-O, O39
-0.01ο
+ 0.0IO
+ 0.0IO
-0.010
-0.015
-0.010
-0.010 2.0
2.9
1.1
1.3
1.0
1.1
1.6
1.5
1.5
1.6
1.7 2.0
8.7
5.6
7.9
.4.9
7.7
4.6
4.6
4.3
5.0
5.0 1
2
* o 3
S «
ao 5
Ot
«O 6
^ 7
2 ⁸
*> 9
10
11 very strong
strong
moderate
small amount '
no £
moderate '
no
no
no
no
moderate

(1) (+) means weight gain, (-) weight loss, N.C. no change in weight

(2) mg KOH / 1 g oil

N) N> 00 CO cn ho

Example 12-15

Dry air was blown through a sample of isooctyl isodecyl adipate at a temperature of 93 ° C. until the thiosulfate titration of these samples _{resulted in a peroxide content of 20 nmoles O 2} per kg of the ester. The aeration time was approximately 2 hours, before and after this treatment there were no visual changes in the ester oil. After the samples had cooled to 27 ° C, this peroxide-containing ester oil was used to produce lubricating oils, the components being used in the amounts given in Table III:

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Table III

Components

Example No. and parts by weight

O CD CO

Isooetyl isodecyl adipate 12th 13th «MM 14th , - 15th (D rricresyl phosphate 0.5 H- {3,4-Diehlorben2y1) - 100 100 1.0 100 2.0 100 3,7-dioctyl-phenothiazine 1 1 - 1 O, O5 3,7-DioEtylphenothiazine 1.5 2.0 Phenothiazine 0.05 • Di (p-octylphenyl) amine - - 3 * -amino-l _r 2 , 4-triazole - - 2.0 0.05

(1)

with a content of 20 mmol O- / 1 kg

NJ

ro

00 CO

cn

200 ml samples of these lubricating oils were tested in an accelerated aging test their shelf life by placing the samples in open ¹ IOO ml beakers mounted v / ere 1 week at 70 ° C in a maintained at a constant temperature drying oven. After the end of the storage period, it was found that the oil from Example 12 with a content of N- (3j ^ -dichlorobenzyl) -3,7-dioctylphenothiazine was free from flocculation or precipitates, and had the clarity that could also be determined before the aging test No change in the peroxide content was found. The lubricating oil from Example 13 with a content of 3> 7-dioctylphenothiazine showed a flaky precipitate after just 3 days. The lubricating oil from Example 14 with a phenothiazine content had darkened very strongly after 1 week, while the lubricating oil from Example 15 without additives did not show a very strong darkening, but showed a very high increase in the peroxide number after 1 week.

In comparison with the other lubricating oils, the lubricating oil according to the invention was found to have a content of N- (3, ^ - dichlorobenzyl) -3,7-ciioctylphenothiazine increased Oxidation resistance, reduced corrosiveness and no change from the original Appearance.

Example 16-27

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From the results given in Table ¹ IV quantities lubricating oils were prepared by homogeneously mixing.

Table IV
Ingredients ■ Example No. and parts by weight

16 17 18 19 20 21 22 23 24 25 26 27

Diisodecyl sebacate 100 - 100 - - loo - - - ■ -

Diisodecyl azelate - 100 - - - - - - loo

Isooctyl-isodecyl-ad-ipat - - - 100 100 - 100 100 - 100 100 100

Tricresyl phosphate 2 1 2 1.51 1 1.51 1 1 1 1

N- (2,4-dichlorobenzyl) -.

χ —— ~~~ ~~~ ■ "" * —— ■ * """——-""—— - ——

3,7-dioctylphenothiazine

Kj N- (3,4-dichlorobenzyl) - _{o Λ c}

_co 3,7-dioctylphenothiazine

N- (4-nitrobenzyl) -3.7- _ _, __ _

cj dioctylphenothiazine ''

"^. N- (2,4-dibromobenzyl) -"

- ^s 3,7-dioctylphenothiazine

ω N- ₁ / '5- (4-tolyl) _z 5,5-di-

■ e- methylpentyl / -3,7-di- - - - - - 2.5 -
octylphenothiazine

N- / 2- (4-chlorophenyl) -2-, 2-dimethylethy] y-3,7-di-— - - - - - 2

octylphenothiazine

N- (3-aminobenzyl) -3,7-dioctylphenothiazine - - - - - - - 1.5 1.5 - -

N- (4-butoxybenzyl) -3,7-dioctylphenbthiazine - - - - - - - - - 1.5 - - f> O

N- (4-hydroxybenzyl) -3,7- [^

dioctylphenothiazine - - - - - - - - - 1,5 - CO

Di (p-octylphenyl) amine 2.5 3 2 2 2 2.5 1.5 1 2 2 1.5 - ^ω

4- (2,2,3,3-tetramethyl- - - - - - - - - - - - 2 ^

butyl) phenyl-2-naphthylamine

3-amino-1,2,4-triazole 0.1 0.05 0.05 1 0.05 0.05 0.05 0.05 0.1 0.1 0.05 0.05

These lubricating oils were tested according to the methods described in Examples 1-11. Compared to Lubricating oil from Example 8 could be slightly varied with respect to the change in viscosity, the Determine acid number and the change in weight of the various metal blocks, but all according to the invention Lubricating oils showed excellent durability and no sludge formation whatsoever.

Example 28 - 3 ^

Lubricating oils were produced from the amounts given in Table V.

Ο 8 S 3/1 0 3 4

Table V

Components Example No. and parts by weight

28 29 30 31 32 33 34

Isooctyl isodecyl adipate '100 100 100 100 100 100 100

N- (2,4-dichlorobenzyl) -3,7- (2,2,3,3-. Ι

° tetramethylbutyl) phenothiazine 1.5 - - - 1.5 - - oo N- (3,4-dichlorobenzyl) -3.7- (2,2,3,3-

ω tetramethylbutyl) phenothiazine - 1.5 - - 1.5 1.5 ' ^. N, N-bis-4- (2,2,3,3-tetramethyl-

° butyl) phenylbenzylamine - - 2.5 - 2.5 2.5 -

Jp ^ N, N-bis-4- (2,2,3,3-tetramethyl- ~ _c .- _c

butyl) -phenyl-2-phenylethylamine

Tricresyl phosphate 1.0 1.0 1.0 1.0 1, O 1.0 1.0

3-amino-1,2,4-triazole 0.05 0.05 0.05 0.05 0.05 0.05 0.05

These lubricating oils were tested for corrosiveness and oxidation stability according to the procedures described in Examples 1-11. The lubricating oils of Examples 32 - J> k showed no sludge formation and thus a synergistic effect of the additives in terms of prevention of sludge formation and improved oxidation stability compared to the lubricating oils of Examples 28-31, which either only have an N-substituted phenothiazine but no tertiary amine or a tertiary amine which did not contain any N-substituted phenothiazine. The lubricating oil from Example 32 with a content of N ~ (2, lJ-dichlorobenzyl) ~ 3,7- (2,2,3,3-tetramethylbutyl) -phenothiazine and N, N-bis- ^ - (2,2, 3,3-tetramethylbutyD-phenyl-benzylamine shows in comparison to the lubricating oil from Example 20, which is not a tertiary amine, but the same N-substituted phenothiazine compound, and in comparison to the lubricating oil from Example 30, which is the tertiary amine, but contains no N-substituted phenothiazine, a substantially lower sludge formation. a similar synergistic activity can be in the lubricating oil of example 33 »in which the 2,4-dichlorobenzyl group of the N-substituted phenothiazine through the isomeric 3» ^ * "dichlorobenzyl Group was replaced, in comparison to the lubricating oils from Example 29 and 30. The lubricating oil from Example 33 also has a similar synergistic effect, which compared to the very low sludge formation occurring there, a considerably greater sludge formation in the lubricating

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-di

of Examples 29 and 30 which do not contain the mixture of an N-substituted phenothiazine and a tertiary amine. The unexpected synergistic effect can also be seen in the lubricating oil from Example 3 ¹ I with a content of N- (3, ⁱ <-Dichlorobenzyl) 3 _a 7- (2,2,3,3-tetramethylbutyl) -phenothiazine and N, N- Bis- * l- (2,2,3,3-tetramethylbutyl) -phenyl-2-phenylethyl-amine, in which hardly any sludge formation could be observed. In contrast to this very low sludge formation, massive sludge formation was found in the lubricating oil from Example 30 with the N-substituted phenothiazine but without a tertiary amine, and severe sludge formation in the lubricating oil from Example 31 with a tertiary amine content but without N-substituted phenothiazine . It can be seen from the table that the lubricating oils of Examples 32-3 ^ have very little sludge formation at high temperatures, improved oxidation stability and practically no corrosive properties, so that they are particularly suitable for the lubrication of thermally stressed parts. The test results are summarized in Table VI:

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Table VI

NJ O CO 00

Lube oil from example

Change of metal weight in it

Increase in
Acid number (2)

Increase in viscosity in
% at 38 ° C

Sludge formation

Mg Al Fe Cu Ag 1.68 1.0 moderate 28 +0.023 +0.046 +0.054 +0.039 +0.054 2.20 1.6 moderate 29 +0.062 +0.092 +0.062 N.C. +0.023 4.80 10.0 moderate 3O +0.031 N.C. . N.C. -0.015 -0.062 1.20 6.2 strong 31 -1,341 --0.046 +0.023 +0.039 +0.015 1.60 5.0 no 32 +0.023 N.C. N.C. -0.010 -0.039 1.10 4.0 no 33 ~ O, O46 +0.031 -0.023 -0.015 -0.054 1.17 3.6 no 34 +0.010 +0.015 +0.015 +0.023 -0.070

(1) (+) means weight gain,

(2) mg KOH / 1 g oil

(-) Weight Loss, N.C. no change in weight

N) N)

00 GO

cn

N)

The lubricating oils from Example 28 Samples ¹ to 3 were prepared according to I in Examples 12 - 15 * comparison described driving on their behavior in the presence of peroxides investigated. All lubricating oils showed excellent storage stability and no formation of insoluble precipitates in the presence of the peroxides when stored for 2 weeks at temperatures of 70 ° C.

The lubricating oils according to the invention show a synergistic one No improvement in reducing sludge formation and increasing oxidation stability only when using a tertiary amine in the amine component, but also when using a secondary one Amines. The results of Tables II and VI show that the lubricating oil from Example 7 in addition to other improvements lead to almost no sludge formation (Table II) while considering this fact does not apply to the lubricating oil from Example 11 (Table II) and the lubricating oil from Example 28 (Table VI) was expected. A similar synergistic effectiveness is shown, for example, in the greatly reduced Sludge formation of the lubricating oil from Example 8 (Table II) in comparison to the sludge formation of the lubricating oils from Example 11 (Table II) and Example 29 (Table VI).

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Claims (1)

Claims 1. Ester lubricant with a content of at least one organic amine as antioxidant _s characterized in that it contains a small amount of an (A) secondary Ν, Ν-diaromatic amine or a tertiary Ν, Ν-diaromatic N-aralkylamine and a smaller amount (B ) contains an M-substituted phenothiazine of the general formula, in which R is a group of the general formulas 209853/1034 in the η O or an integer from 1 to U, R, - and Rg, which are the same or different, each Hydrogen atoms or a methyl group and in which A, B, D, E, P, G and J are each hydrogen atoms or an amino, halogen, nitro, hydroxy, CL üi.s C.pl2 alkoxy or CL to C. _? Mean alkyl group, provided that at least one of these substituents is not a hydrogen atom, and in which R,., Rp, R, and Rj, can be the same or different and in each case hydrogen atoms or an alkyl, alkoxy or aralkyl group with up to 12 C denotes atoms, provided that at least one of the substituents R ₁ , R ₂ , R-, or R _{11 is} a C ^ to C ^ ₂ -alkyl or alkoxy group. 2. Lubricant according to claim 1, characterized in that A, B, D, E, P, G and J in the general formula of the phenothiazine (B) hydrogen -, ".- chlorine or Bromine atoms or amino, nitro, hydroxy or C ^ to C.ρ alkoxy groups. 3. Lubricant according to claim 1, characterized in that it is phenothiazine (B) N- (3, 'l-dichlorobenzyl) -3,7-clioctylphenothiazine, M- (2, '(-Dichlorobenzyl) -3> 7-dioctylphenothiazine, M- (3,4-dichlorobenzyl) -3> 7 ~ 20985 3/1034 (2,2,3,3-tetramethylbutyD-phenothiazine or Μ- (2, Ί-dichlorobenzyl) -3,7- (2,2,3,3-tetramethylbutyl) -phenothiazine contains. Ί. Lubricant according to claims 1 - 3> characterized in that it contains a di- (PC _1. To C. _? Alkylphenyl) -amine as amine (A). 5. Lubricant according to claims 1-3 »characterized in that it contains a tertiary amine (A), in which the aralkyl group (Ri.) of the amine follows has general formula: C (CH ₀ ) - '2 ' x \ D B in which n, R ₁ -, Rg, A, B, D, E, F, G and J have the meaning given in claim 1, except that A, B, D, E, F ₅ G and J can all be hydrogen atoms . 209853/1034 6. Lubricant according to Claim 5 _3, characterized in that the amine (A) has the following general formulas 2 * 1 has, in which R ^ is an aralkyl group with the meaning given in claim 5, and in R ₂₁ , ^R 22 ^JR 23 ^{> Κ} 2 * 1 ^UI ^ ^{d R} 25 S ^le i- ^cJl or different and in each case hydrogen atoms _{, C 1} to C 1 P alkyl or C 1 to C 1 P alkoxy groups, provided that at least one of these substituents _{R p 1} , R “p, R p _{1 and R p 1} . is no hydrogen atom, and in the Rpg and Rp ₇ each C ₁ to Alkyl or until Mean alkoxy groups. 209853/1034 7. Lubricant according to claim 1 to 6, characterized in that that it is up to 1 part by weight per 100 parts by weight of the ester oil of a triazole or a substituted one Contains triazoles. 8. Lubricant according to claim 1 to 7, characterized in that there are up to 10 parts by weight per 100 parts by weight of the ester oil of a phosphorus-containing acid ester contains. 9. Lubricant according to claim 1 to 8, characterized in that the ester oil is a diester of the general formula R ₇ OOC (CH ₂ ) _n COORg, in which η is an integer from 2 to 3 ¹ ^ and Ry and Rg are each an even - Or branched-chain alkyl, phenoxyalkyl or alkyloxyalkyl groups with 6 to 20 carbon atoms. 10. Lubricant according to claim 1 to 9 _3, characterized in that there is about 1 to 4 parts by weight of the amine component (A), about 0.5 to 3 parts by weight of the M-substituted phenothiazine (B) about 0.5 to 100 parts by weight of the ester oil Contains 5 parts by weight of a phosphorus-containing acid ester and about 0.01 to 0.2 parts by weight of a triazole or substituted triazole. 209853/1034