DE1261617B - Lubricating oil - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

Number:
File number:
Registration date:
Display day:

ClOm

German class: 23 c -1/01

1261 617
S93880IVc / 23c
October 23, 1964
February 22, 1968

It is known to use arylamines and thiodiarylamines as antioxidants in synthetic lubricants to be used for aircraft turbine engines, and their combined use has already been recommended is to increase the per se lower antioxidant effect of certain substituted phenothiazines.

It has now been found that triaryl esters of phosphorothionic acid are not used alone as antioxidants are effective in synthetic ester lubricating oils, but in combination with arylamines and Thiodiarylamines in ester lubricating oils in a synergetic manner with regard to increasing the resistance to oxidation work together and produce better results than the known lubricating oils to lead.

The lubricating oil according to the invention based on aliphatic carboxylic acid esters, containing a mixture an arylamine and a thiodiarylamine, is characterized in that it also contains a triaryl ester the phosphorothionic acid of the formula, preferably in amounts of 0.5 to 10 percent by weight, based on the lubricating oil

Lubricating oil

S = P

in which R is hydrogen or an alkyl radical with up to 8 carbon atoms.

The aryl radicals of phosphorothionic acid preferably contain no more than 14 carbon atoms. Examples: triphenyl, tritolyl, tribenzyl, trixylyl, and trioctylphenyl phosphorothionate. Triphenyl phosphorothionate however, it is preferred.

These triaryl esters can be used in concentrations between 0.5 and 10 percent by weight, preferably between 2.0 and 7.0 percent by weight, based on the finished lubricating oil mixture, are present.

Examples of arylamines are phenyl-c ^ naphthylamine and alkyl derivatives of this compound. Examples of thiodiarylamines are phenothiazine and 3,7-dioctylphenothiazine.

These arylamines and thiodiarylamines are used in amounts of 0.5 and 5.0 percent by weight, preferably of 1.0 and 3.0 percent by weight, based on the lubricating oil, is added.

Applicant:

Shell International Research

Maatschappij N.V., The Hague

Representative:

Dr. E. Jung, patent attorney,

8000 Munich 23, Siegesstr. 26th

Named as inventor:
Francis Henry Waight,
Alexander Colquhoun Barr Macphail,
Wirral, Cheshire (UK)

Claimed priority:

Great Britain October 25, 1963 (42137)

Aliphatic carboxylic acid esters are used as the base lubricating oil. Suitable esters are the aliphatic esters of a monobasic carboxylic acid with A to 18 carbon atoms in the molecule and a glycol with 4 to 20 carbon atoms per molecule, for example esters of neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol or dipropylene glycol and heptanoic acid , n-octanoic acid or pelargonic acid.

Esters of monocarboxylic acids with 4 to 18 carbon atoms in the molecule, such as butyric acid, are preferred and pelargonic acid, with polyhydric alcohols with 4 to 12 carbon atoms per molecule, z. B. pentaerythritol or trimethylolpropane, e.g. B. pentaerythritol tetrabutyrate and trimethylolpropane trihepthylate. Mixtures of these esters can also be used.

The lubricating oils according to the invention can also contain other known additives, such as extreme pressure agents, Thickeners, anti-varnish agents, anti-foaming agents, dyes, anti-corrosion agents and contain other antioxidants.

The synergistic effect of the combination according to the invention is shown in Tables I and II (IX to XIV are lubricating oils according to the invention, I to VIII are lubricating oils according to the prior art).

The Rolls Royce Blown Oxidation described below was used to test the mixtures Test used "in which the effect of the anti-

809 5ÖJ / 299

Oxidizing agent is expressed in changes in viscosity and acid value. The corresponding Experimental results are shown in Table II.

Rolls Royce Blown Oxidation Test

Under controlled conditions, a 50 ml sample of the oil to be tested is added a temperature of 220 ° C for a period of 192 hours with 250 ml per minute Water vapor, saturated air or nitrogen passed through. The decomposition that occurs as a result of oxidation of the lubricating oil mixture is then determined by the change in the acid value, by changes the viscosity and the content of components insoluble in benzene.

Table I.

Composition of the test mixtures in percent by weight

II

III

VI

VII

VIII

IX

XI

xir

XlII

Trimethylolpropane tripelargonate

Esters of pentaerythritol and C ₅ _ ₁₀ fatty acids

Esters of pentaerythritol and Q_ ₈ fatty acids ..

Esters of dipentaerythritol and
Cg-io fatty acids

2,2,4-trimethyl pentyl azelate

Phenyl-a-naphthylamine. 3,7-dioctylphenothiazine. Triphenyl phosphorothionate

Chlorinated di- or polyphenyl

5-methylbenzenetriazole ..

1,3,5-trimethyl-2,4,6-tris- (4-methylene-2,6-di-tert-butylphenol) benzene ..

2,3,5,6-Tetramethyll, 4-bis (4-methylene-2,6-di-tert-butylphenol) -benzene

Polydimethylsiloxane 12,500

Azelaic acid

*) ppm = parts per million.

63.0 19.5

61.0 19.5

94.98

94.98

60.0

19.5

58.0

19.5

58.0
19.5

58.0
19.5

91.98

91.98

72.98
19.5

53.0 19.5

14.48

3.0 25 ppm *)

14.48

2.0

3.0 25

2.0

3.0

25th

25 2.0

3.0

25th

14.48
1.5
1.5

3.0

25th

14.48
1.5
1.5

■ 3.0
25th

2.0

14.48
1.5
1.5

3.0
25th

14.48
1.5
1.5
2.0

3.0

25th

1.5
1.5
2.0

3.0

25th

1.5
1.5
2.0

3.0

1.5
1.5
2.0

3.0

25th

25th

14.48 1.5 1.5 7.0

3.0 25

5 ppm *) 0.02

5 0.02

0.02

0.02

0.02

0.02

2.0

0.02

0.02

0.02

0.02

0.02

0.02

Table II

Trial mix

In benzene

insoluble

Weight percent

Start viscosity in cS at 98.9 ⁰ C

End of increase (%)

Acid value in mg KOH / g start end

II

III

IV

VI
VII

Feast Feast Feast Feast

0.02 0.008

0.017. 0.008

4.84 5.08

19.4. 305 25.1 418 27.8 446 18.2 258

0.10
0.10

6.05 6.15 6.55. 6.20

continuation

Trial mix

In benzene

insoluble

Weight percent

Viscosity in cS at 98.9 ⁰ C start end increase (%)

Acid value in mg KOH / g

Beginning

end

VIII

XI

XII

XIII

XIV

0.012
0.008

nothing
nothing

0.003
0.02

0.005
0.005

0.004
0.02

0.006
0.01

0.05
0.01

} 4.80} 5.02} 4.90

5.00 \ 5.04

5.47 {

32.6 547 59.2 1080 11.9 148 12.0 150 13.5 169 13.6 171 12.2 149 12.4 153 13.6 172 13.2 164 11.7 132 12.1 140 9.43 72.5 10.13 85.2

The numerical values in Table II confirm that the presence of a triaryl ester phosphorothionic acid, which when used alone in such a synthetic ester lubricating oil shows practically no effect as an antioxidant (cf. Examples II to V), the resistance to oxidation of such an ester lubricating oil, which also contains arylamines and thiodiarylamines, is very essential is improved. This increase in resistance to oxidation comes from the reduction in the proportion of components insoluble in benzene, in the values for the viscosity increase and in the values for the Increase in the degree of acidity in the oxidation test described above for expression (cf.Examples IX to XIV).

The improvement achieved according to the invention is also significantly greater than when other known ones are used Antioxidants (see Examples VII and VIII).

Claims (1)

Claim: Lubricating oil based on aliphatic carboxylic acid esters, containing a mixture of a 0.10
0.10
0.10
0.10
0.10
0.10
0.20 6.30 6.20 4.90 4.60 4.00 3.10 4.45 3.35 4.80 4.70 3.75 3.65 4.60 3.60 Arylamines and a thiodiarylamine, thereby characterized in that there is also a triaryl ester of phosphorothionic acid of the formula S = P in which R is hydrogen or an alkyl radical with up to 8 carbon atoms. References considered: Australian Patent No. 236,748. 809 509/299 2.6S © Bundesdruckerei Berlin