CA1088506A

CA1088506A - Lubricant containing organo sulfur-containing nickel complexes

Info

Publication number: CA1088506A
Application number: CA259,076A
Authority: CA
Inventors: Eldon L. Armstrong; Samuel J. Leonardi
Original assignee: Mobil Oil Corp
Current assignee: ExxonMobil Oil Corp
Priority date: 1975-08-15
Filing date: 1976-08-13
Publication date: 1980-10-28
Also published as: SE421429B; NO762814L; DK367076A; JPS6014793B2; TR19122A; FI60885B; AU501498B2; BE845054A; PT65462B; IT1066053B; NO143707C; NL7608842A; BR7605333A; JPS5224203A; CH602909A5; SE7608973L; FI762327A; ATA608976A; FI60885C; DE2636583A1

Abstract

LUBRICANT COMPOSITIONS

ABSTRACT OF THE DISCLOSURE

Lubricant compositions are provided containing a stabilizing amount against ultra-violet degradation of an organo sulfur-containing nickel complex.

Description

- 108~506 BACKGROUND OF THE I~VENTION

Field of the Invention This invention relates to lubricant compositions, and relates more particularly to lubricant compositions normally subject to degradation by ultra-violet light present, for example in such sources of actinic radiation, as sunlight.
Still more particularly, in one of its aspects, the invention relates to lubricant compositions, such as oils of lubricating viscosity, hydrocracked lubricating oils, hydraulic oils, mineral oils or fractions thereof, automotive oils, gear oils, transmission fluids, waxes, greases and other forms of lubricants normally requiring the presence of stabilizing agents against the degradation effects of ultra-violet light.

Description of the Prior Art In general, the production of lubricant compositions, for example, lubricating oils produced by hydrocracking, affords a relatively high viscosity index and permits the use of certain stocks that would be unsuitable for other processes. On the other hand, however, hydrocracked lubricating oils tend toward poor stability against ultra-violet light degradation, rapidly forming suspended and/or precipitated insoluble material on exposure to ultra-violet light, such as sunlight, or other ~` -sources of actinic radiation. Compounds capable of absorbing ultra-violet light, for example, hydroxybenzophenones, and hydroxyphenyl benzotriazoles, have afforded some improvement in the light stability of hydrocracked oils. Conventional antioxidants have also provided some benefit.

10~8S06 In the literature, Reskins and Guillet in ~Mechanism of ~ltraviolet Stabilization of Polymers", Macromolecules 1, 97 (1968) first proposed the energy transfer mechanism of ultra-violet protection. Commercially available ultra-violet stabilizers are also listed by class and function and identified as to structure in the Kirt-Othmer Encyclopedia in "Encyclopedia of Chemical Technology"; Second Edition, Vol. 21, pp. 115-122.
Uri in "Thermal and Photochemical Oxidation of Polymers and Its Prevention~, Chemistry and Industry, March 1, 1975, pp. 199-203, cites conventional antioxidant effects (hydroperoxide decomposi-tion and free radical capture) of bis(stilbenedithiolato)nickel and its ultra-violet inhibiting properties. In British Patent Specification 1,263,910 (1~72), there is disclosed bis(stilbene-` dithiolato)nickel as an antioxidant for plastic materials. The i~ specification also cites superior hydroperoxide decomposition ;~ capability of this additive. U.S. patent 3,832,304, discloses the use of aromatic azo compounds for stabilizing hydrocracked oils. None of the foregoing disclosures show lubricant compo-ii~ sitions containing the organo sulfur-containing nickel complexes

2~ described herein~

SUMMARY OF THE INVENTION

In accordance with the present invention, we have j~ found that degradation against ultra-violet light, present in sunlight or other sources of actinic radia~ion can be effectively imparted to lubricant compositions by the incorporation therein of organo sulfur-containing nickel complexes. These nickel complexes are particularly effective against ultra-vi~let degradation in such lubricating media as oils of lubricating ~ 0~s06 viscosity, hydrocracked lubricating oils, hydraulic oils, mineral oils or factions thereof, automotive oils, gear oils, transmission fluids, waxes, greases and other forms of lubricant compositions normally requiring the presence of stabilizing agents against the degradation effect of ultra-violet light, In particular, there is provided by the present invention, a lubricant composition comprising a major proportion of a hydrocarbon oil lubricant and a minor proportion, suf-ficient to provide stability of said composition against degradation by ultra-violet radiation, of a nickel complex phenol sulfide complex.
The organo sulfur-containing nickel complexes can be effectively employed in any amount which is sufficient for imparting to the lubricant the desired degree of protection against ultra-violet degradation. In many instances, the nickel complex is effectively employed in an amount from about 0.01 to about 5%, by weight, and preferably in an amount from about 0.1 to about 2%, by weight, of the total weight of the lubricant composition. The term "nickel complex", as used herein is intended to include nickel compounds having a chelate ring formation. As hereinbefore indicated, the organic sulfur-containing nickel complexes may be incorporated in any lub-ricating media ~hich can include oils of lubricating viscosity and also greases in which any of the aforementioned oils are employed as vehicles. In general, synthetic oils can also be effectively protected against ultra-violet degradation or may also be employed in combination with mineral oils, or as grease vehicles. Typical synthetic vehicles include polyisobutylene, polybutenes, hydrogenated polydecenes, polypropylene glycol, polyethylene glycol, trimethylol propane esters, neopentyl and ~O~B506 pentaerythritol esters, di(2-ethyl hexyl) sebacate, di-(2-ethyl hexyl) adipate, dibutyl phthalate, fluorocarbons, silicate esters, silanes, esters of phosphorus-containing acids, liquid ureas, ferrocene derivatives, hydrogenated mineral oils, chain-type polyphenols, siloxanes and silicones (polysiloxanes), alkyl-substituted : ' , ~ .

~' - 4a -l~W506 i, diphenyl e~hers ty?ified by 2 butyl-subs~l~uted bis-(o-phenox~

i phen~ri) e~her, phenoxy phenyle~her, e~c.
~! Par~icul2rly desir~ble organic sull~u~-containing !~ nickel complexes in accor~2nce wi~h ~he presen~ invention include commercially available nickel pheno~ sulf des, n~ckel alkylthio-amines, nickel dithiophospha~es and nickel dithioca-bama~es.
Nickel phenol sulfid-s may be employed having, rOr example, the structure:

in which R is either hydrogen or an alkyl group hav~ng up to 30 carbon atoms.
Representætive of the nickel phenol sulrides ~re nickel bis(octylphenol) sulfide having the structuro:

~S~
8H~ 7 8H17 and nickel bisphenol su~fide havin~ the structure:

Ni O~ I ' ~
~ 1 ~

The sulfur-containing nickel phenol-phenolates are useful materials. They are described, for example, in U.S.
Patents Nos. 2971940 and 2971941. They comprise nickel salts of bisphenol sulfides in which only a portion of the total phenolic hydrogen has been replaced by nickel. They may have formulae such as the following:

R R
~f ~3 , o\ I o~

H Ni I \
\0/

:: :

. ' 1;
~ ~ ; ~ ;

~ OH
HC~ ¦ ~ OH

R R

5(a) lOW506 wihcre R is H or an alkyl group, suitably of up to 30 carbon atoms.
A mixture of these two compounds (designated here as "Mixture A"), where R is octyl, is a good ultra-violet stabiliser.
Sulfur-containing nickel amine complexe3 are descrlbed in U.S. Patents Nos. 3215717 and 3313770.

~(b) 1~850~; ' Representative of the nickel alkylamines i5 [2,2'-thio-bis(4-tert-octylphenolato)l-n-butylamine nickel having the structure 8H17 ~3 \\ .
S ~i NH2C4Hg C8H17 ~ (~/

Representative of the nickel thiophosphates is nickel di(4-methyl-2-pentyl) dithiophosphate having the structure C6H13\ S ~ i / 6 13 C H 0/ ~ S D \ OC H

Representative of the nickel dithiocarbamates is nickel dibutyl dithiocarbamate having the structure , ,;~ / N - C ~ Ni ~ ~ C4H9 ~ C4H9 ''~

lO~S06 ' DESCRIPTION OF SPECIFIC EMBODIMENTS
. .

In order to evaluate the effectiveness of the organo sulfur-containing nickel complexes of the present invention against ultra-violet degradation in lubricant media, the following test was employed:
This test untilized a base oil, viz. a hydrofinished hydrocracked 100" oil obtained by dewaxing 725F bottoms from a first-stage product of a fuel hydrocracker. ~lends of additives with the aforementioned hydrocracked base oil were tested by subjecting 20 grams of the test oil in a capped four-ounce tall form bottle to daylight on a window sill with a southeast exposure. The test oil was observed each day for "
suspended insoluble products, which usually progress from a haze to a suspended floc and precipitates, which generally are preceded by hazes or flocs, and often consist of settled haze or floc. In the following Table I are recorded the results ; obtained employing 0.1 weight percent additives in the afore-mentioned hydrocracked base oil. From the table, it will be noted that the nickel complexes of the present invention are much more markedly effective against ultra-violet degradation (Examples 2-6) than the best of the commercially available conventional antioxidants and ultra-violet absorbers (Examples 7-11).

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In the following Table II are recorded the results obtained employing 0.5 weight percent additives in the above-described hydrocracked base oil of Table I. Here, also, it will be noted from the table that, when subjected to the above-described test, the organo sulfur-containing nickel complexes in the lubricant compositions of the present invention are much more markedly effective against ultra-violet degradation (Example 2-4) than the best of the aforementioned commercially available conventional antioxidants and ultra-violet absorbers (Example 5-9).

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tl_ 108~506 In the following Table III is shown the effectiveness of a typically representative nickel complex of the present invention viz. nickel bistoctylphenol)sulfide in a 200" hydro-cracked base oil (Base oil 1) and also in another base oil (Base oil 2) viz. a heavy vacuum gas oil. As shown in the table, the nickel (octylphenol)sulfide of the present invention was markedly effective in reducing the ultra-violet degradation of the respective base oils.

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~n ~he follo~in~ ~able _~.~ is sh~wn he effec~ eness of ~ cally re?resen~at,ve nickel co.~?lexes of ~he present nven~ion, as æntioxidants in lubricant composl'ions. The re~resentat,ve additives were ~ndividually blended in l~O
sol~en~-ref,ned ~araffinic mineral oil and were sub~ected to the standard Rotary 30mb Oxidation Test in accordance wlth test method ASTM D-2272.
As w'll be noted from the table, +he oxidation life of the base oil was markedly increased by the antioxidant effect imparted by the nickel complexes of tbe present 1nvention.

:, ~' . ~

f ~

'~
- ~ ~

,:
~ -15-1~.~506 TA3L~

hn~ioxid~nt E~fec~s o~ Nickel ComDlexes F~, R30T Life, ~nutes 1 None (~ase Oil) 37 2 1$ ~2,2'-thio-bis(4-tert-oc~lphenolato)~-n-butylamine nickel 60 3 1~ Mixture A 8 O
1~ Nickel di(4-methyl-2-pen~yl) dithiophosphate 180 0.2~ Nickel dibutyl-dithiocarbamate 230 .

1' ~

~ ~.

~ .

- ,5_ ;-'hile ~h s ,n~er.~ion has been desc-_bec w_th re~erence to pre~erred compositions ~nd conponents therefor, i~ will be ~ders~ooc b;~ ~hose skilled in the art that de~ar~ure from the preferred embod~ments can be effecti~ely made and are w~thin ~he scope of the specification.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A lubricant composition comprising a major proportion of a hydrocarbon oil lubricant and a minor proportion, sufficient to provide stability of said composition against degradation by ultraviolet radiation, of sulfur-containing nickel phenol-phenolates and mixtures thereof having the following formulae:

wherein R is hydrogen or an alkyl group containing up to 30 carbon atoms.

2. The lubricant composition defined in claim 1 wherein R is an octyl group.

3. The lubricant composition defined in claim 1 wherein the sulfur-containing nickel phenol-phenolates are present in an amount from about 0.01 to about 5%, by weight.

4. The lubricant composition defined in claim 1 wherein the sulfur-containing nickel phenol-phenolates are present in an amount from 0.1 to about 2%, by weight.

5. The lubricant composition defined in claim 1 wherein said lubricant comprises a hydrocracked lubricating oil.

6. The lubricant composition defined in claim 1 wherein said lubricant comprises a hydraulic oil.