US2983681A - Lubricating compositions - Google Patents

Description

we provide United States Patent Crystal Lakey-lll -assignors ito' The'Pure Oil Company,

Chicago, 111., a corporation of Ohio No Drawing. "Filed May 14, 1957,"Ser.No. 658,940

Claimsr 01; 252-464 Thisfinvention "relates'to lubricating oil oompositions containing smallamounts of sulfurized isoprenoidcompounds 'and'small amountsof organiccompounds containing phosphorus, .arsenicior antimony, which compositions lexliibitimproved antiwear properties and oxidation stability, Morekparticularly, theinvention relates to the ui mvery that theflmcombination of sulfurized isoprenoid compounds andorgariophosphorus, organoarsenic or orjganoantimonycompounds in lubricating oilsforms a superior 'antiwear composition as, exemplified by itsperforr'nancerin "the four ball extreme pressure machine, whereina synergistic effect hasbeen found .to take place between the. compounds of the aforestatedgeneral classification. a l

Organocomp'ounds of groupVB elements, that is, phosphorus, arsenic, antimony and-bismuth, are bestknown for their inhibition of oxidation processes,although certain of these compounds are described as having some extreme pressure properties when used in lubricating oil compositions. Similarly, sulfurized isoprenoid compounds are known for their ability to impart oxidation stability and non-corrosive properties tolubrica'ting compositions used in the presencevof alloyed bearings. Sulfurized isoprenoid compounds have in some instances been used for theiriextreme pressure properties. However, it is.also well-known that complex addends of the types aforementioned, which are efiective for improvement-indetergency,

oxidation resistance or corrosion resistanceof lubricating oils, are often prone to produce high wear-rates'when-used in; the lubrication of=-stee1 lsliding on steel. Known detergents, oxidation inhibitors, and corrosion-preventing adtlends are generally considered to-be ineffective as extreme pressure agents under the severe conditions that are found "jiri; modern extreme pressure tests, such as the Shell fouroball test: g

The present invention is predicated on the-unexpected discoverythat-the combination of antioxidants and detergpnts consisting of s ulfur containing isqprenoid com- 4 ndsand,organooonipounds of phosphorus, arsenic and ,[aruin onyexerts a synergistic antiwear efiectandproduces lovr wear rlateseas measured by the four ball test. The estraordinary efi ect of' the specific combination of aduenqs t-ur ,of theadd 'ds namely the organocompouiids of group YB, elements, rpducesiiar greater 'wear ,with the 'mineral ,lubricat' g oilrthap the oil alone prod ucesi, Furthermore,

{it will; be demonstrated that the unusual antiwear prop- H 11 1 entionfis emphasized by the, factithat one i aerties of thecombination,of addends o f this invention is rtain members of the broad group of ch they fall, such as combinations of uthines', representing the remaining meman extreme pressure lubricating composition icontaining the combination oi: sulfurized isoprenoid com:

compounds, withjsulfurized, isoprenoids, ,prihi arylobject ofthis invention is to mer ts of f f p' VB tha'di'ene and terpinolene. i

revised edition, 1953) excluding bismuth and nitrogen.

The isoprenoid compoundswhich are employed to produce the sulfurized derivatives used as a part of the composition of this invention include 1 the alicyclic, monocyclic,and dicyclic terpenerhydrocarbons, and are wellknownin the art. The terpenes have the general formula C H and many arediolefinic derivatives-of cyclohexane. The more complex alicyclic terpenes are the sesquiterpenes, C H and the.polyterpenes (C H Among the open-chain terpenederivativesare 2,6-dimethyloctatriene, geraniol, linalool, citronellol, citrolellal and rhodinal. Among themono'cyclic terpe'nes which are considered to be derivatives of p-menthane, orHl-methyl-Lisopropylcyclohexane, are a-terpinene, gamma-terpinene; u-phellandrene, fi-phellandrene, terpinolene, limonene andmenthadiene, B-ter'pinene and pseudoli-monene. The most im- 'portant monocyclic terpenes are limonene, a-terpinene and a-phellandrene. Para-menthane may be derived from 'menthol by reduction, menthol being associated with terpenes in essential oils. \Otheroxidation derivatives of -p-menthai1e, also associated with terpenes in essential oils,

are carvomenthol, pulegone, u-terpineol, menthane and carvone.

d-Limonene'is found'in all citrusoils. l-limonene occurs in pine needles and fir cones and oil of peppermint. The racemic modification, dipentene, is found in many essential oils. 1 Dipentene is found in turpentines and obtained by thedistillation of pine wood. *Dipentene may be regarded a dimer ofisoprene and may be produced therefrom by polymerization, ot-Teipineol can be formed from the dehydration of terpin hydrate which maybe produced from dipentene or geraniol.

Among the dicyclic terpenes which are considered to be cyclohexane witha bridge of one or more carbon atoms, the" most important members arejcarene, pinene, and camphane. Thesedicyclic isoprenoidsmay be consideredto be derivatives of p-menthane byhaving-theisopropyl' group close abridging ring acrossthe cyclohexane ring. tandfl-Pinene are obtained, the former in a proportion of 9=Q%,by distillation of the yellow pine resinexudate from pine' trees. Turpentine oils contain p-cymene. Terpinolene,a monocyclic diene, is prepared synthetically from terpineol by dehydration with oxalic acid.

H Fenchone is another bicyclic' te rpenede rivative under the camphane group and is isomericwith camphor. The treatment of a-pinenewith dry hydrogen iodide produces bornyl iodide which on reduction yields camphane.

The isoprenoid compounds found in naval stores 1 products may bevused, such as the constituents of a-pinne, gum andtwood turpentines, and ithe constituents ofdipenteneml22 or pine oils. range'from cyelofenchenelboiling at about 143 i'C. .to u- Specifically, these materials terpineol boilingtat 237 C., includingsuchwell-known isoprenoids as a-pinene, camphane," fl-pine-ne, ot-terpinene,

dipentene, 'p-cymene, 'gamma terpinene, 2,4( 8 para-men- Typical commercial proprietary terpene products by prenoid compounds scribed in the following United States Patents may be used:

1,844,400Kobbe 2,417,305-Know1es 2,443,823-Ho1t V 2,689,846- Beegle In general, the 'sulfurization of the isoprenoid is carried out by adding an amount of sulfur which is-stoichiometrically in excess of the amount required to react with the doublebonds present in the isoprenoid, and heating the mixture in a kettle or stainless steel autoclave at temperatures ranging from 250" F. to 400 F. for a time sufiicient to complete the reaction. The isoprenoid compound used should have at least one unsaturation in the molecule. In general, it is preferred to use ordinary flowers of sulfur during the sulfurization step in proportions of about 20 to 35 parts by weight, especially 25 to -30 parts of sulfur, for each 100 parts of reaction mixture, or about 25 to 54%, based on the weight of isoprenoid compound. The ingredients may be combined by heating the isoprenoid compound and adding the sulfur thereto; or,'the sulfur may first be melted and the terpene added gradually thereto; or, the ingredients may be combined .without prior heating and thereafter heated together to a temperature above the melting point of the sulfur. This is followed by further heating to about 300, to 400 F. Non-limiting examples follow:

EXAMPLE I Three hundred grams of terpinolene and 90 grams of sulfur are mixed and placed in a 1000 cc. stainless steel autoclave. Heat is applied and the mixture is maintained at about 340 F. for about 30 minutes. The temperature is raised to about 360 F. for another 30 minutes with agitation. A pressure of about 50 p.s.i.g. develops. The autoclave is then cooled and the reaction mixture is subjected to vacuum steam-stripping to 300 F.

at. about 15 mm. Hg.. The product may be used as such, or purified by dilution with an equal volume of benzene and refluxed with agitation for four hours at 185-190 F. in the presence of a solution consisting of about 600 grams of water, 300 grams of sodium sulfide (Na S-9H O), and 100 grams of sodium hydroxide.

Themixture is thenqallowed to cool, 500 cc. of pentane are addedsan'd the mixture is shaken. A bottom layer of a dark orange-red liquid is drawn off and the upper layer .is washed several times. with water. This top layer is filtered and the benzene and pentane is removed by evaporation on a steam bath.- The product, sulfurized terpinolene, is a yellow-brown liquid containing about 29 to 30% sulfur.

' EXAMPLE II Two hundred grams of steam-distilled pine oil, containing as its main constituent alpha-terpineol (B.P. 422-424 F.), is heated at 220 F. with 50 grams of sulfur. Asthe temperature rises, the sulfur melts and dissolves in the pine oil. When the temperature reaches;

a about 350 F., ebullition takes place and an exothermic .reaction begins which brings the temperature to about 375 F. After; heating for 4-5 hours at 375400 F., a homogeneous mass is obtained and purification is carried out asin Example I. I i

' .EXAMPLE III By heating600'grams of terpinolene to 330 F. in a l Ck flask equipped'with a mercury-seal stirrer'and two reflux condensersjadding gradually 180 grams of "sulfu'lrthrough'one of thecondensers at a rate to mainf 'tainthe temperaturea't 350 F.,.heating to about 350'F.

for. 2 /2 hours; cooling, filtering, -and vacuum steam- 'stripping to 300 F; and purifying in accordancewith EXample 'I,-.a prbductQcontainingabout 29% sulfur, a

- -;yellowish-brown i oil, is obtained.

he qrsa cs pqun s'atmosphe es. se c a timony tobe used in accordance with this invention may.

have organic radicals of the aliphatic, carbocyclic, including alicyclic and aromatic, and heterocyclic series having a total of from 3 to 30 carbon atoms. Thus, the phosphines, arsines and stibines include compounds which 5 contain the specific groups of trimethyl, dimethylethyl,

methylethylpropyl, methylethylcetyl, dibutylcetyl, triethyl, tripropyl, triisopropyl, tributyl, triamyl, dimethylbutyl, tricety l, methyldiphenyl, diethylbenzyl triphenyl, tritolyl, and tripyridyl. Other specific compounds include 'dibutylphenylphosphine, dilaurylphenylphosphine, and diwaxphenylphosphine. Particularly applicable to the invention are those organocomponnds of phosphorus, arsenic, and-anti-mony in which the organo portion of the molecule contains only carbon and hydrogen.

In order to illustrate the invention, a number of lubricating compositions were prepared and subjected to tests on the shell four-ball EP machine in which a steel ball is rotated in contact with 3 stationary balls submerged in the test oil. This machine may be used'to determine characteristic properties such as wear-rate under various conditions, load-carrying capacity, or ability to prevent seizure and welding under high loads. The test used to evaluate the oils of this invention was a wear test of 5 minutes duration, a rotational speed of 1800 r.p.m., for

the top ball, and an applied load of 20 kg. Wear measurements are the average diameter in mm. of the scars produced by the rotating ball on the three stationary balls. A low-wear lubricant will produce a scar diameter only slightly greater than the diameter ofelasiic indentation of the balls, which in the caseof the stated load and ball composition used is 0.24 Table I shows some results obtained with the compositions of our'invention containing triphenyl derivatives of group VB elements.

Table I Lubricant Composition, Wt. Percent 4-Ba1l l VtVear Group V Organo- Increase compound Sulfur- Basic 170 vis. in av. scar ized Ba-Sul- Mineral dia. over terpene fonate Oil Hertz Element Wt. Perdia., mm.

cent

1. l 0.7 98. 2 0.03 1.1 0. 7 5. 3 92. 9 0.03 1.1 98. 9 0. 34 1.0 0.7 6.3 93.0 0. 03 1. 0 a 90. 0 0. 04 0.8 V 0.7 5. 3 98. 5 0.02 0.8 i 99. 2 0.05 0.7 5. 3 94. 0 0.12 0. 7 99. 3 0. 08 100.0 0.14 0.8 0. 7 5.3 93.2 0.09 0.8 99. 2 r 0513 1.4 -0.7 5.3 92.6 0.20

It will be seen from Table I that antiw'ear properties are exhibited to a marked degree by oil blends containing the additive combinationjof sulfurized terpene and a phosphine arsine or stibine. The antiwear properties are also maintained in are presence of a commonly used "motor oil detergent additive, basic barium'petroleum'sulfonate." fin this table the average wear values were obtained from three or more individual runs for each lu- "bricantfiThe individual, additives do' not necessarily show antiwear properties; ,in fact, triphenylstibine in :mine'ral oil shows a higher wear rate than mineral oil alone. Examples of oil; blends containing brganocompounds of the other two elements jof groupVB, vi'z.,

nitrogen'and bismuth, are included to compafethe in- TOQferior wearprotection'afiorded by combinations ofyaddiltivescontaining thesetwo elements with the sulfurized .t p -f Components. of "the above lubricantcompositions may i be further identifiedfas follows. The organoc ompounds of group VB elements withwhich' mamyemia rs'ooav cerned were all triphenyl derivatives and equivalent molar concentrations were used. The sulfurized terpene was a commercial product containing 29.4 wt. percent sulfur and having a specific gravity of 1.164. The sulfonate was a commercial basic barium petroleum sulfonate containing 15.9 wt. percent sulfated ash, and having a total base number of 30. The mineral oil in the above blends was a Mid-Continent solvent-refined neutral oil with a viscosity of 170 SUS at 100 F.

Although the lubricating oil compositions of this invention are illustrated by compositions containing a major proportion of a neutral oil, a minor proportion of a compound selected from the group consisting of triphenylstibine, -arsine, and -phosphine, used at a concentration of 0.8 to 1.1 wt. percent, and a minor proportion of a product characterized as a sulfurized terpene, used at a concentration of 0.7 wt. percent, it is to be under stood that the invention encompasses alkyl, aryl, alkaryl, arylalkyl, carbocyclic, including alicyclic and aromatic and heterocyclic phosphines, stibines and arsines, in which the organic radicals are the same or dilferent. It is apparent also that other lubricating oil fractions may be used and that the proportions of the different constituents may vary within the broad limits disclosed. Other additives, such as detergents and pour depressants normally used in modern motor oil formulations, can also be incorporated while maintaining the advantages of the preferred combination of sulfurized terpene and triarylstibine, arsine or phosphine, or other antiwear additive combinations as set forth herein.

What is claimed is:

1. A lubricating composition comprising a major portion of a mineral lubricating oil, about 0.2 to 5.0 weight percent of a sulfurized terpenic compound selected from the group consisting of sulfurized pine oil, sulfurized terpinolene, sulfurized dipentene and sulfurized pinene, and about 0.2 to 5.0 weight percent of an organocompound selected from the group of triphenylphosphine and triphenylstibine said sulfurized terpenic compounds and said organo-compound being essentially the only antiwear constituents present in said composition.

2. A lubricating composition comprising a major portion of a mineral lubricating oil and about 0.7 weight percent of a sulfurized terpenic compound selected from the group consisting of sulfurized pine oil, sulfurized terpinolene, sulfurized dipentene and sulfurized pinene and about 0.8 to 1.1 weight percent of an organocompound selected from the group consisting of triphenylphosphine and triphenylstibine said sulfurized terpenic compound and said organo-cornpound being essentially the only antiwear constituents present in said composition.

3. The lubricating composition of claim 2 in which the sulfurized terpenic compound is sulfurized pinene.

4. The lubricating composition of claim 2 in which the sulfurized terpenic compound is sulfurized pine oil.

5. The lubricating composition of claim 2 in which the sulfurized terpenic compound is sulfurized terpinolene.

6. The lubricating composition of claim 2 in which the sulfurized terpenic compound is sulfurized dipentene.

7. The lubricating composition of claim 2 in which the organocompound is triphenylphosphine.

8. The lubricating composition of claim 2 in which the organocompound is trlphenylstibine.

9. An extreme pressure lubricant comprising a major portion of a mineral lubricating oil, about 0.7 weight percent of sulfurized terpene and about 1.1 weight percent of triphenylstibine said sulfurized terpene and said triphenylstibine being essentially the only antiwear constituents present in said lubricant.

1 0. An extreme pressure lubricant comprising a major portion of a mineral lubricating oil, about 0.7 weight percent of sulfurized terpene and about 0.8 weight percent of triphenylphosphine said sulfurized terpene and said triphenylphosphine being essentially the. only antiwear constituents present in said lubricant.

References Cited in the file of this patent UNITED STATES PATENTS 2,149,271 Butz Mar. 7, 1939 2,334,566 Lincoln Nov. 16, 1943 2,443,823 Holt June 22, 1948 2,643,248 Brennan June 23, 1953

Claims (1)

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PORTION OF A MINERAL LUBRICATING OIL, ABOUT 0.2 TO 5.0 WEIGHT PERCENT OF A SULFURIZED TERPENIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF SULFURIZED PINE OIL, SULFURIZED TERPINOLENE, SULFURIZED DIPENTENE AND SULFURIZED PINENE, AND ABOUT 0.2 TO 5.0 WEIGHT PERCENT OF AN ORGANOCOMPOUND SELECTED FROM THE GROUP OF TRIPHENYLPHOSPHINE AND TRIPHENYLSTIBINE SAID SULFURIZED TERPENIC COMPOUNDS AND SAID ORGANO-COMPOUND BEING ESSENTIALLY THE ONLY ANTIWEAR CONSTITUENTS PRESENT IN SAID COMPOSITION.