US2362293A - Lubricant - Google Patents

Description

Patented Nov. 7, 1944 UNITED STATES PATENT OFFICE v John G. McNab,

LUBRICANT i Roselle, and Walter T; Watkins,

" Jr., Elizabeth, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. f Application December 30, 1939,

Serial No. 311,838 I 16 Claims.

This invention relates to a novel type of metal compounds and methods .of. preparing same', and relates more particularly to theuse of these novel compounds as addition agents in hydrocarbon compositions, especially in lubricating oils, for improving the same.

It has been found that hydrocarbon compositions, especially hydrocarbon lubricating oils, are greatly improved by adding thereto win small amounts. of a class of metal compounds of which the cobalt salt of tertiary amyl phenol thioether is representative. This compound, which might also be called a cobalt tertiary amyl phenol sulamyl phenol-,-

fide, or a sulfide of cobalt tertiary ate, is believed to have the formula:

where'n is one or more. If the various groups attached to the aromatic nucleus areso positioned that the amyl group is in an ortho' position to the oxygen, and the sulfur linkage isin a meta position to the oxygen, this compound probably ha the followin graphic formula in its simplest form:

11 I C5Hi1 I v i S 7 or if preferred by the group S'-S, or even higher polysulfides may be used.

These various compounds can be produced by preparing the corresponding alkyl phenol sulfides or disulfides, which per se are known, and converting these into the corresponding sodium or potassium salts thereof, as by treatment with sodium or potassium hydroxide, and then converting the resultant derivative" of the alkali metal into the corresponding derivative of cobalt by any suitable means, such as by double decomposition with a suitable corresponding cobalt compound, such as the chloride, nitrate, etc.

The invention may be described more broadly as comprising a substituted phenolate compound of a metal of group VIII, series 4, of the Mendeleefl Periodic Table, containing at least one grouping having the general formula:

wherein M represents the metal constituent connected through Y to at leastone aromatic nucleus, Y is an element in the righthand side of group VI of the periodic table ,(Mendeleefi), Ar

represents an aromatic nucleus which contains like or unlike substituent X, n in number, replacing nuclearhydrogen, nbeing at least 1.

The substituents, X, may be organic, inorganic, or both, for example, alkyl'radicals and groups containing one or more of the non-metallic ele- -ments belonging to groups V, VI, and VII of the periodic system (Mendeleefi): nitrogen, phosphorus, oxygen, sulfur, and halogens, as in amino, nitro, phosphite, phosphate, hydroxy, alkoxy, sulfide, 1 thioether, mercapto, chloro groupings, and the like. v

In the phenolate salts constituting blending agents featured by this invention, valences of the metal other than those connected to the-substituted phenolic radicals, such as OAr(X)n,'are

connected through oxygen to other organic groups or to inorganic constituents, suchas hydrogen,

phosphorus, etc. For convenience, non-phenolic radicals or groups, as well-as phenolic groups, at-

tached to; the metal are indicated broadly by OR in the following types of compositional formulae, which broadly represent metal derivatives of substituted phenolic compounds containing the characteristic compositional grouping described: Where M is divalent:

Where M is trivalent:

MO--Ar(X) More specifically, some of the structures which the substituted phenolates may have are indicated in the following list of formulas containing benzene nuclei having compositions such as C6Hk, CsHa-, etc., with X, as before, standing for nuclear substituents (e. g., --CnH2n+1, -NO2, -Cl, --S--, 82-, -NH(CnH2n-}-l), etc.): When the metal is divalent: f

--OC Hs- -9 (kHz- When the metal is trivalent:

Somewhat more specifically, the cobalt, nickel or iron derivatives may be used of the following type of phenolic compounds:

Especially preferred are" the compounds containing at least one grouping having the general formula:

where M is the metal, Ar is an aromatic nucleus, R is an organic group, Z is a member of the sulphur family and n is an integer of 1 to 5. Z is preferably sulphur and the small n is preferably 1 or 2, although for some specific purposes it may" be 3 or more. R represents an organic group which may be either aryl, alkyl, aralkyl, alkylaryl or cycloalkyl and which may contain substituent groups such as halogen, particularly chlorine, nitro, nitroso, amino, hydroxy, car-boxy, alkoxy, aroxy, mercapto, and the like, but preferably is or contains an alkyl or alkylenyl group,

and preferably contains at least 4 carbon atoms.

An important feature of this invention issues from the observation that metal salts are benefited in solubility and effectiveness as hydrocarbon lubricating oil blending agents where they contain a total of at least 8 and preferably 9 or more carbon atoms per molecule in aliphatic groupings when sulfur is present in the molecule, and at least 16, and preferably 20 or more, carbon atoms if no sulfur is present. Products lacking slightly in the desired solubility characteristics can be assisted into solution by the use of mutual solvents such as alcohols, esters, chlorinated materials, etc. Another valuable feature is that inorganic substituents, particularly negative inorganic groups containing non-metallic elements of groups V, VI and VII of the Mendeleefi Periodic System, and preferably sulfur as mentioned earlier, beneficially influence the metallic salts by increasing their potency for stabilizing the lubricating oils and by making the salts, in themselves,

more stable, as, for instance, against high temperature and to some extent against hydrolysis. Specific examples of preferred substituted phenolates falling into the classes mentioned, having a divalent metal constituent, e. g., cobalt, nickel or iron, and having an alkyl radical as a substituent are formulated as follows:

I. Alkyl phenolates e.- g., salts of di-t.-amyl phenol salts of tert-octyl phenol II. Alkyl chlorphenolates M(.O.CeH3C1.CnHan+1) 2 e. g., salts of 2 chloro, 4 tert-amyl phenol salts of 2, 6 dichloro, 4 tert amyl phenol salts of 6 chloro, 2, 4 diamyl phenol III. Alkyl amino phenolates e. g., salts of amyl, para-amino phenol salts of N-amyl, para-amino phenol IV. Thioethers of alkyl phenolates e. g., thioether of salts of tert-amyl-phenol v. Disulfides of alkyl phenolates C Ha-H VI. Alkyl nitrophenolates M[.O.CsI-I3(NO2) (CnH2n+l) 12 e.g., salts of alkyl nitro phenol sulfide In the case where themetal is trivalent such as ferric iron, 1, 2, or all 3 of the valences of the metal may be connected to a phenolic oxygen (or sulphur in case a thio-phenolic compound was used). metal the thioethersof alkyl phenolate may have a formula such as the following:

zuocsHacnHannsn As these substituted phenolates are generally made by reacting the corresponding phenols with a metal oxide or hydroxide (either the one desired, or the sodium or potassium compound to be converted into the-one desired), the amount of metal in the phenolate product will depend on the proportions of reactant used, and if products having different proportions are possible, the

products will usually consist of a mixture, which 7 may be used as such or may be separated into several constituents. For instance, as will be seen from the experimental data given later, nickel derivatives oftertiaryamyl phenol thioethers have been prepared which contain 3 different proportions of nickel. It is probable that the normal compound containing 1 nickel atom per thioether molecule, which should contain 18% MO, should have the following graphic formula:

tf-CsHn I tr-CsHu I on the other hand, if only enough metal is reacted with the phenolic compound to combine with one of the hydroxyl groups it is likely that the resultant product will have the following graphic formula: 1 d I p Finally, by using an excess of the metal, in

using the cobalt or like salt for the double de-,

composition it is possible to make compounds containing e'venmore metal than 1 atom per dihydroxy thioether molecule.

As seen from the above description, the metal compound preferably has the general formula:

where M is a metal selected from the group consisting of cobalt, nickel and iron, R represents one or more alkyl groups having enough carbon atoms (preferably a total of' at least 10) Ito insure solubility of the total compounds in mineral oil, is an aromatic nucleus, preferably a ben- For instance, in case of a tri-valentzene nucleus, :0 is 1 or 2, and n is thevalency of the metal. ,More particularly, compounds hav-.

ing the following general formula-are preferred:

M(CnH2n+1.C6H3.0) 2s where'M is cobalt, nickel or iron, nls at least 4, and preferably 5, or more, and where the group C1|H21|+1 is preferably a branched alkyl group.

For the objects stated, the metal phenolates u have been preferably prepared from phenolic compounds readily obtainable by alkylation of the-simple phenols or by extraction from high boiling petroleum oils. 7

Suitable synthetic alkyl phenols for preparing the desired phenolates are principally of the secondary and tertiary types, because alkylation of a simple phenol occurs more readily with branched aliphatic reactants. Commonly, the alkylation reaction involves a condensation of olefins with the simple phenols, the reaction being catalyzed by anhydrous metal halides, sulfuric acid, phosphoric acid, or certain activated clays.

As olefinic reactants, refinery gases containing propylene, butylenes, amylenes, etc., are economically useful, although individual oleflns, e. g., isobutylene,iso=amylene, diisobutylene, triisobutyl- I ene, etc., or olefin-containing mixtures from other sources may beusedx The reaction temperature is usually controlled to avoidsidereactions. In

employing sulfuric acid, a liquid phase reaction at relatively low temperatures is preferred; with phosphoric acid the reaction may be carried out inthe vapor phase.

As starting materials for conversion into the metal phenolates, the phenols maycontain one or more substituents which provide a desired numberof saturated carbon atoms in groups hav- 1 ing the form of straight chains, branched chains,

or even rings. Monoalkyl or polyalkyl phenols are synthesized conveniently by alkylating a phenol with branched chainolefin polymers, such as diisobutylene, di -tert-,amylene, or other suitable agents, such as alcohols, alkyl sulfates, alkyl phosphates, or alkyl halides, thereby forming carbon-to-carbon bonds between the aromatic nuclei and the alkyl groups.

Petroleum phenols which qualify for the present purpose are considered to contain polymeth ylene or. cycloalkyl side chains, as evidenced by their hydrogen and carbon analysis. The petroleum phenols are obtained by extraction of various stocks, chiefly from cracking process heating oil stocks, with caustic soda, and acidification of the alkaline extract with a weak mineral acid, followed by a non-destructive distillation if desired.

By using the described methods or any other well known method for preparing alkyl phenols,

the following alkylated phenols may be procured for preparing the phenolates, e. g.,' tert-amyl phenol, iso-hexyl phenol, ,tert-octyl phenol, di-

tert-butyl phenol, di-tert-amyl phenol, di-normal amyl phenol, etc.

Inorganic substituents are introduced into alkyl phenols by well known methods. For example, an alkyl phenol, e. g., tert-amyl phenol, is reacted with sulfur mono-chloride, S2012 in about 1: mole ratio and preferably in a solvent such as dichlor-ethane, to produce the alkyl phenol disulfide. Using substantially the same procedure but substituting sulfur dichloride, SClz, for

. the mono-chloride, the alkyl phenols are given a thioether. linkage substituent. Alkyl chlorphenols are obtained by chlorination, preferably controlled to replace nuclear hydrogen by a chloro group. This may be accomplished by chlorinating the phenol before alkylation. In such a manner, for example, 2-chlor-4-tert-amyl phenol can be produced. Nitro substituents are introduced readily into the aromatic nucleus by direct nitration, and nitro substituents can be reduced to amino groups. It is to be understood, however, that the preparation of substituted phenolic compounds which have been described does not form part of this invention and that any of the well known methods for their production may be used.

The following experimental data illustrate the preparation of some cobalt andnickel derivatives of the substituted phenolic compounds according to this invention.

EXAMPLE 1 Cobalt salt of tertiary amyl phenol sulfide 7.7 grams (V mole) of sodium were dissolved added. 23 grams (21.7 equals 5 mole) of cobalt chloride, C0012 (anhydrous) were dissolved in 250 cos. of absolute ethyl alcoholand added to the above mixture with agitation. The solution solvent for the nickel chloride, a better reaction 60 grams (/8 mole) of tertiary amyl phenol sulfide were dissolved in 100 cos. of absolute methyl alcohol an added to a solution of 7.7 grams graintomLoPsodi'um dissolved in 150 cos. of methyl alcohol. 28 grams (21.6 grams equal mole) of anhydrous nickel chloride(NiClz) were dissolved in 300 cc. of absolute methyl alcohol by refluxing, and after cooling this solution was added to the alcohol solution of sodium tertiary amyl phenol sulfide prepared first. A precipitate formed and another 60 cc. of alcohol were added and the mixture was permitted to stand over night. After recovering th precipitate, dissolv- 1 ing it in 54 naphtha, filtering off the residual turned brown. The alcohol was stripped'off and the brown residue was agitated with 54 naphtha in which the cobalt salt of tertiary amyl phenol sulfide dissolved very readily, the sodium chloride resulting from the double decomposition remaining insoluble. The solution was filtered free of sodium chloride and then distilled to strip off the naphtha. 70 grams of a dark chocolate colored product were obtained. This product, which was cobalt, tertiary amyl phenol sulfide, dissolved readily in a naphthenic base lubricating oil having a Saybolt viscosity of about 55 seconds at 210 R, such as is suitable for use as a crankcase lubricant for Diesel engines. Analysis indicated that this cobalt salt contained 17.65% of 00:04 (theoretical 19.36).

EXAMPLE 2 Nickel salt of tertiary amyl phenol sulfide solution of the sodium tertiary amyl phenol sulfide. The mixture was refluxed for 4 hours and graduallyturned a dark green color. After refiuxing for 24 hours more the solution was filtered free from insoluble materials (mostly so-' dium chloride and-some unreacted-nickel chlo-- ride), and the alcohol was stripped off the filtrate yielding 67 grams of a green solid which was readily soluble in the naphthenic oil base stock reterred to in Example 1-. Analysis of the productindicated a content of 6.40% of nickel oxide expressed as NiO. Based on the formula the reaction did not go to completion because the calculated content of NiO should be 18.0%.

This experiment was repeated using absolute methyl alcohol instead of ethyl alcohol as the A light solvent na h t-ha havin a boilin ran e oi 160-240 F. p g g g sodium chloride and evaporation of the naphtha, a yellow-colored product was obtained which had a nickel oxide content of 17.9% NiO, which corresponds closely with the theoretical 18.0% .for the compounds having the formula This product is also soluble in th naphthenic oil referred to.

EXAMPLE 3 Nickel methozco saltof tertiary amyl phenol sulfide 15.5 grams gram atom) of sodium were dissolved in 300 cc. of absolute methyl alcohol. 60 grams (V6 mole) of tertiary amyl phenol sulfide dissolved in cc. of methyl alcohol were added. 44 grams (23.2 grams equal M; mole) of anhydrous nickel chloride (NiClz) were dissolved in 400 cc. of dry methyl alcohol by refluxing. The nickel chloride solution was added to the i above with agitation. A precipitate formed, and

after standing for several hours the solution was filtered off, the precipitate being air-dried and the alcohol being stripped off from the filtrate. 30 grams of green solid were obtained from the filtrate and 114 grams of light-green solid from the precipitate. The two solids were combined and warmed with 54 naphtha, cooled and then filtered after standing over night. The naphtha was stripped off from the solution and a yield of 91 grams of an oil-soluble green solid was obtained which had a content of 27.45% of nickel oxide (N10), which corresponds closely to the theoretical 27.90% calculated for the formula (C5H11- CeI-I3ONiOCH3)2S, the nickel methoxo salt of tertiary amyl phenol sulfide.

EXAMPLE 4 Nickel salt of tertiary amyl phenol disulfide tertiary amyl phenol disulflde with agitation.

After standin theprecipitate which formed'was" filtered off and dried. The yield equalled 68 rams. I I I The filtrate was stripped free of alcohol, leaving a residue of 39 grams. These two,'residues were combined and'refluxe'd with 54 naphtha for a few minutes, cooled, settled'for a, day and'the supernatant liquid was drawn off'j and" stripped free of naphtha, leavinga' residue" of '75 grams ofgreenish-yellow solid which dissolved readily in the naphthenic oil referred to in Example 1 on heating. This product contained 15.49% of nickel oxide (NiO), which corresponds fairlywell with the theoretical 16.72% calculated for the formula Nl(C5H11C6H3O)2SS, the nickel salt of tertiary amyl phenol disulfide.

I ExAMPLn 5 i Cobalt salt of tertiary amyl phenol sulfide This is the laboratory method of preparation which was subsequently adopted 'for the commercial manufacture of cobalt tertiary amylphe- 71.6 grams-of tertiary amyl phenol sulfide were used to improve the lubricating or oiliness characteristics of the lubricating oils.

These metal compounds mayalso be used as improving agents in other hydrocarbon oils or products, such as waxes, fuel oils,'Diesel fuels,

naphthas, gasoline, burning 0'11, and the like.) These-"metal compounds may also be'usedas improving agents .in products derived from petroleumpils or indifferent types of products such as 'fattyfoilsfsoaps, aldehydes, resins, rubber, paper, and various synthetic products which tend to deteriorate by oxidation either alone or in accompaniment with. other chemical phenom"- dissolved-in 300 cc..of 98% isopropyl alcoholby warming and agitation. 16 grams of flake caustic soda were added and the mixture warmed to about 150 F. and agitated until the caustic sodawas completelyreacted to give ayellowish-brown solution of sodium tertiary amyl phenol sulfide in thealcohol. A solution of 27.6 grams of cobolt chloride hexahydrate in 150 cc. of isopropyl alcohol,.'prepared bywarming the alcohol to about 125? F. and stirring, was then added; with Y stirring, to the alcoholic. sodium tertiary amyl phenol sulfide solution, producing a brownish paste of cobalt tertiary amyl phenol sulfide suspended in alcohol. 320 grams of a Coastal naphthenic lubricating oil base stock having a viscosity of about 55 seconds Saybolt at 210 F. (a suificient quantity to give a 20% solution of the I cobalt salt) was then added and the-alcohol was removed by stripping in vacuum; In .order to assist in removing the'lastportion of the solvent, the product was blownwith air. ,The finished product was filteredthrough paper and the filtered 20% concentrate of cobalt tertiary amyl phenol sulfide in the, naphthenic lubricating oil base stock Was found upon analysis'to contain 3.42% of cobalt oxide (C0304) (which checks satisfactorily with the theoretical amount of 3.33%). a

Corresponding cobalt, nickel or iron salts of other alkyl phenol sulfides may be prepared, for instance, by substituting polysulfide or polymers, such as the dimers, trimers, and tetramers of the alkyl phenol thio-ethers used in the above examples. Also, the corresponding metal salts of the corresponding selenides and telluride's may be prepared, although the sulfur compounds are preferred.

The various products obtained may-be puriiied, if desired, by fractionalcrystallization, ex-

traction, precipitation with selective solvents,

etc. Also, impurities may be removed by treatment withsuitable adsorptive agents such as clay.

While these compounds or mixtures thereof,

alone or in admixture with corresponding alkyl phenol sulfides, may be added in any desired concentration within their solubility limits'to lubricatingoils, they are preferably used in concentrations of about 0.0l to 2.02%, about 0.1 to 1.0%

being generally sufficient to impartsludging-relubrication of internal combustionfengines.

These oils may be obtained from. yarious'types of 'cru'des such as 'par'aflinic, naphthenic, as-' phaltic, 01 mixed crudes, and. they may be eithe r plain distillates or fractions obtaine'djby treating or refining by various methods known to the art, such as acid treating; clay treating, solvent, extraction, dewa'xing'etc 'ortheymay be synthetic oils resultingfrom various types of. 'chem'- ical reactions such as cracking polymerization;

condensation,and thelike: In preparing finished lubricants according to this invention as "described above, other kntwni addition agents may also be used such as other known efl'ective anti-oxidants,dyes,.soaps, pour inhibitors, sludge dispersers, etc.

Although .the invention is of primary importance for preparing Diesel engine lubricants, itis also useful for other types of crankcase lubricants,steam cylinder oils, greases, upper cylinder lubricants, sludging oils, etc.

The invention has numerous advantages, some of which are apparent from the preceding dis-' cussion, but it should also be pointed out that these derivativesof cobalt; nickel and iron cause very remarkable improvement in the performance of such internal combustion engines, particularly when'contrasted with materials used heretofore in such engines when operated under severe testing conditions, such as at high speed and high temperature, etc;- Another very impora' tent feature of this invention is that the metal compounds disclosed herein, especially the cobalt compounds, are particularly valuable for their anti-corrosion enhancing properties" formation of acid compounds on the part0 bricating oils through oxidation in servic causes corrosion ofalloy bearing metals," e. g. copper- 1 leadjsuch corrosion is also caused or, accelerated by certain compounding agents frequently added to mineral oils to improvethe "engineperformance. Hence, the present invention finds par-I ticular application by incorporating these novel metal compounds in a'lubricating oil or'other hydrocarbon composition which is normally cor rosive to metals such as alloy bearingmetals,

etc.

Another advantage of this invention -is thatthese metal compounds, especially the .nickel compounds such as the nickel. salt of tert'iaryfl amyl phenol thio-ether, haveexceptionally high solubility in mineral oils, particularly in parafllnic oils in which 'many other types of metal com.

pounds are 'relatively insoluble. -AIsO these novel mineral compounds are especially good for keepsistant properties to the majority of lubricating oils. Larger amounts up to 5% or more may be The metal compounds of thisinventioniare es; pecially useful for improving mineral lubricat ing oils, particularly those used. for crankcase The I flliing piston rings clean in an internal combustion engine and due to. their non-corrosive or anticorrosive properties, they can be used in oils containing substantial amounts of sulfur, either in the mineral oil itself or in some additive such as tertiary amyl phenol sulfide or corresponding disulfide, where other metal compounds would cause staining of copper and other metals. The nickel compounds of this invention are both noncorrosive and highly oil soluble, by reason of which properties lubricants to which these nickel compounds are added have new and unexpected properties and are adapted to obtain results never heretofore obtained.

These and other advantages of the invention will be still better understood from an examination of the following engine test data.

0.25% solution of various metal derivatives 'of tertiary amyl phenol thio-ethers such as prepared above under Examples 1 to 5, dissolved in mineral lubricating oil base stock were subjected to a number of oxidationand sludging tests and were subjected to a number of tests in the C. F. R. (Cooperative Fuel Research) engine for 15 hours at 390 F. After each run, the engine was taken the reference rating. of the blend is expressed as "per cent of reference and is calculated .as fol lows:

Per cent of reference demezn't time-8 100 Flank oil demerit The lower the "per cent of reference the better is the oil according to this engine test. The results'or these tests are reported in Table I.

amount of oxygen (measured in cubic centimeters) absorbed in successive 15-minute intervals.

' The results of Table I show, most importantoi all, that in regard to the C. F. R. engine demerits, the niokel and cobalt compounds of this invention cause a very substantial improvement in the blank oil, tests 3, 4, 5 and 7 showing respectively a per cent of reference of 28, 13, 30 and 9, compared to 100 for the blank oil. As will be noted from the table, the improved results are attributable both to the prevention of ring sticking and reduction of carbon formation, thereby resulting in a much lower piston overall demerit rating than in the case of the blank oil. It will also be noted from the above table that, in spite of the fact that the metal" additives used are compounds of metals which are well known to be great oxidation accelerators, the oxidation rate of the blank oil was not substantiaily raised in any case except in test 4 where the nickel compound used contained a substantial excess of nickel over the stoichiometric amount required to combine with the two hydroxyl groups in the tertiary amyl phenol thio-ether. It is also significant, on the other hand, that the oxidation rate of the blank oil was not lowered in any of the blends having a lower 0. F. R. engine demerit rating than the blank oil (demerit ratings being lacking for the only two blends which showed a slight reduction in oxidation rate). Consequently, it is evident that the oxidation rate bears little if any relationship to the actual engine performance of a lubricating oil as measured by the engine demerit rating, and so this oxidatiomrate is relatively unimportant.

Tsar: I

Test

. c el ry m N w igg Blank Gal. NiO-lS. tertiary amyl Cobalt amyl phenol phenol A B C sulfide disulilde Percent N10- 17. 85 Oxid. rate .i-.- 56 74. 86 43 48 4O 30 35 28 48 A g 2 4 verage 54 C. F. R. eng demcritsr Percent rei: 28 9 3. 51 l. 44 0. 41 2 0 D 4. 2 0.17 Almen wts. carried... 2 l4 The blank oil used in the above test was an 6 extracted par'aflinic fraction obtained from a Mid-Continent crude, and was; a lubricating oil base stock, the representative inspection of which is:

Carbon residue; .24

The oxidation test referred to above comprises bubbling oxygen through a 10 gm. sample of the oil at a temperature of 200 C. (392 F.) and at It should also he noted in the above Table I that both nickel and cobalt derivatives of tertiary amyl phenol thio-ether (tests 2 and 7) possess the property of increasing the load carrying capacity of the blank oil, since blends containing the nickel and cobalt compounds carry 13 and'l4 weights, respectively, whereas the blank oil'only carries 2 weights (the Almen test is made on the Almen pin test machine as described by Mougey and Almen in the Proceedings of A. P. 1., 1931, page 277).

As explained previously, the invention has been found particularly useful for preparing Diesel engine lubricants by adding small amounts of the novel metal compounds of this invention a rate or 700 cc. per min. and determining the 76 to a Diesel engine lubricating oil base stock Such base stocks should, in general, have the following general characteristics:

the plain oil had an overall piston demerit of 1.45 at the end of the first 110-hour running period, theblend containing the nickel salt (test L'imm prgrmed I 2) had an overall demerit of only 1.20 (83%01 11ml reference) and the two cobalt blends had overall demerits of 1.07 (74% of reference) and 0.95 g 1 (66% of reference), respectively, after the same rm, .---.--IIIIIIIIIIIIFII 400 420 period of running. This shows that the nickel Viscosity "seconds r t 40-95 and cobalt salts produce a marked improvement in the engine performance. That this improve- Minimum a I I ment was not merely a temporary coincidence Inasmuch as thediflerent types of Diesel enbut was a true characteristic of the blend which gines operate under somewhat difierent condipersisted throughout. the engine test, even after tions of speed, temperature, etc. and have diflong running periods, is indicated by a compariierent lubricating oil requirements owing to the 5 son of other figures in column 2 for the diflerent different designs of the engine, some tests were tests. For instance, after 539 hours of nmning, made on a Caterpillar singlecylinder Diesel "enthe plain oil in test 1 had an overall demerit glue and also on a Hercules Diesel engine. of 2.45, whereas the blend containing the cobalt In the Caterpillar Diesel engine test, four runs salts (test 3) had a demerit of only 2.04. after were made, No. 1 on a plain naphthenic oil A 985 hours (almost twice as long) and the cobalt (Grade SAE No. 2 a blend of that oil plus salt blend in test 4 had an overall demerit of 0.5% of nickel tertiary amyl phenol sulfide, No. 3 only 1.45 after 496 hours (almost equivalent to the same oil base stock plus 0.5% of cobalt the 539 on the plain oil). For comparison with tertiary amyl phenol sulfide, and No. 4, another the nickel salt blend in test 2, after 349 hours run somewhat similar to No. 3 but made at a of running, producing an overall piston demerit later date and with the engine in somewhat of 1.40, the overall demerit of the blank oil diflerent condition than during run No. 3. The (test 1) for a corresponding length of time is results of these four tests run on the Caterfound by interpolation (graphically from the pillar Diesel engine are recorded in Table II. rest of the data on test 1) to be about 2.20,

TABLE H I I Demerlts Test Overall No. 01] Hours h Ring zone Skirt Varnish on emer cleanliness Carbon and on mm grooves liner skirt 110 1.45 3.10 a 3.40 2.17 1.5 2.0 1 Naphthenic oil A, S. A. E. 30 242 1.96 4.33 3.87 2.92 2.0 4.0

349 1.40 3.50 3.40 1.00 1.0 4.0 113 1. 07 2. 70 3. 30 0. 80 0. 6 1. 0 230 1.30 3.40, 3.30 0.00 0.3 1.5 3 on .4+0.5% 0000113311 015 1.01 4.40 4.00 0.00 1.0 3.0 101 1.14 4.10 3.30 1.30 0.1 5.0 985 2.04 5.50 3.10 1.30 1.5 3.0 111 0.05 1.00 3.30 0.02 0.15 1.0 4 on A+0.5% 00150113010 201 1.33 3. 40 3.40 1.21 1.00 1.5

1 Salt of tertiary amyl phenol sulfide.

The inspection record of the plain naphthenic oil base stock A used in test 1 and the blends containing the metal compounds used in tests 2, 3 and 4 are shown in Table IV further on.

In Table II the most important results are shown in column 2, namely, the overall piston demerit which is a single figure calculated to summarize the various demerits estimated for the diflerent parts of the pistons, several of the more important ofwhich are recorded in columns 3, 4, 5 and 6. Column 1 shows the number of hours of running of the engine up to the time when the particular observations recorded in columns 2 to '7 were made by stopping theenglue and taking it all apart and examining the diflerent parts. The great value of theinvention will readily be seen by comparing the overall piston demerit of the blend used in tests 2',

3 and 4 with the overall piston demerit of the.

blank oil in test 1 for any particular corresponding number of hours of running. For example, it will be noted in column 1 thatunder tests 1,

11mg showing that also the nickel salts'of the 1 tertiary amyl phenol sulfide caused big improve ment in the performance of this naphthenic oil base stock in the CaterpillanDiesel/engine. For the sake of exact comparison, the overall piston demerit for each of the four tests, 1 to 4, at exactly the same number of hours of' running, namely, 500, was estimated graphically by interpolation or extrapolation from the results in columns 1 and 2 of the above Table II, 'and 7 1 As estimated graphically by interpolation or extrapolation.

2, 3 and 4 the first observation were made at 110, 109, 113 and 111 hours, respectively, and

that these times of duration are very close together or substantially identical and yet whereas Thus it is apparent that the superiority of the blends prepared according to this invention be-, comes relatively even greater where the engine tests are continued for. a longer periodoftime.

were made, No. 1 being a plain naphthenic oil 13 (s. A. E. 40) and No. 2 a blend of that same oil containing 0.5% of cobalt tertiary amyl phetheir suitability for use in engines equipped with such sensitive alloy metal bearings. very severe conditions were imposed (atmospheric no] sulfide. These Hercules Diesel engine tests temperature 125 F'., bearing temperature 210 were both run for 84 hours andthe results are 5 F., and oil temperature 195-210 F.) to simulate reported in Table III. the most severe conditions which could be en- TABLE III countered in regular field operations. Neither the nickel tertiary amyl phenol sulfide blend nor 84 w HETWZQS Diesel 6 9 6 tests the corresponding cobalt salt blend showed any 10 greater tendency to corrode copper-lead bearings Test run No.- than did the uncompounded oil. The results of these tests are recorded in Table V. 1 2 TABLE V \I h 011 B+0.5% l

A g 0.01m High temperature Caterpillar engine copper-lead (s A. E. 40) gg fi bearing corrosion tests sulfide (Weighffloss Dernerits of engine: grams mm co per-lead Overall den m-1t 8623 Q15 0 Hours p 1'. 04 1: 04 Weighing 9] 50 approx. 650 Crankshaft. 1.50 0. 50 grams Rings and grooves (composite rat- 1 2 45 1 85 mg NaplitlienicoilA (S.A.E.30) 60 31 g' fggg Tmgsm fig 011 A+0.5% cobaltsalt 50 0.029

m w 20 0 A+1.0%n; ke1sn1 50 0.018 Bearing dfis'ibhi'lfj 066 061 011 A+l.0% nickel soap of a fatty acid 60 5. 069

Total weight loss (gm) from six copperlead connecting-rod 1saltfftertiaryamy}phenoxsulfidebefirmgs- Sim1lar tests were made on an oil compounded Table III shows that after 84 hours of runnlng with 0.5% of the same cobalt salt in 2. Caterpillar in the Hercules Diesel engine the plain naphengine equipped with a, cadmium-silver connecttlienic oilB had an overall demerit of 2.06, whereing rod bearing. Again no corrosion was exas the blend containing 0.5% of cobalt tertiary perienced; the results are recorded in Table VI. amyl phenol sulfide according to the-present in- TABLE VI vention (test 2) had an overall demerit of only 1.71, which shows a very distinct improvement H'lgh'tempfiature cfltermllar fmgme cadmiumin engine performance. It will also be noticed silver bearing 0017051011 te ts from the last line in thisTable III that the addition of the cobalt salt to the naphthenic 011 did (weighgzfloss not cause any increase in the bearing corrosion iii ni gi loss. This is a very important fact, because usu- 011 Hours gag n ally heretofore practically all addition agents gg which were effective in improving the engine per- 550 gms. formance of lubricant; for Diesel engines caused a, very serious increase in the bearing corrosion P 28 loss of copper-lead connecting rod bearings as 011 A+[l,5%coba1t5a1t @1014 well as other alloy bearings. 120

0 lA 1. k 1- i t tt The inspection record of the naphthenic 011 B I 0% me 9 mp0 8 a alone and together with the addition of 0.5% of 50 1 Salt of tertiary amyl phenol Sum/(1g cobalt tertiary amyl phenol sulfide used in these otal. two Hercules engine tests, are shown in Table IV. For the sake of comparison with the valuable TABLE IV Inspection record of- Caterpillar tests Hercules tests Type of sample I I Naph- 011 5+ 011 5+ Naph-. 011 13+ thenic 0.5% 0.5% thenic 0.5%

oil A nickel cobalt oil B cobalt s A.E.3(l Sau salt S.A.E.40 salt 1 22.8 22.1 22.0 21.9 21.1 405 405 410 420 420 450 455 514. 0 531. 5 521. 5 114 11s. 5 55.1 50.5 55.0 62.6 03.3 39 41 as 25 a0 -10 -10 -5 -15 -15 0. 05 0. a0 0. 21 0. 01 0.38 0.25 0.05 0.14 0.11 Saponiflcation No 0.07 0.56 0.69

1 Salt of tertiary amyl phenol sulfide.

Oils compounded with nickeland cobalt derivatives of tertiary amyl phenol sulfide were also tested in a Caterpillar engine equipped with' a and significant result discussed above in connection with Tables V and VI, corresponding results are also shown for a blend of the same lubricatcopper-lead connecting rod bearing. to determine ing oil base stock containing 1.0% of a nickel In this test fatty acid soap. As indicated in Tables V and VI, these nickel soap blends caused an exceedingly great corrosion loss ofboth the copper-lead and the cadmium-silver bearings. This emphasizes the extreme value of the present invention which provides nickel and cobalt salt, which eifects a great improvement in engine performance of Diesel engine lubricants, but without at the same time causing any substantial increase in bearing corrosion loss.

This invention is not to be limited to any of the specific examples presented herein, which were given solely for the purpose of illustration, nor by any theory as to the mechanism of the operation of the invention, but only by the following claims in which it is desired to claim all novelty inherent in the invention as far-as the prior art permits.

We claim:

1. A lubricant comprising a major proportion of mineral lubricating oil and a small amount of a compound containing at least one grouping having the general formula:

R- r--Z,.- wherein M is a metal of group VIII, series 4, of the Mendeleeif Periodic Table, Ar is an aromatic nucleus, R is an aliphatic hydrocarbon substituent having a sufficient number of. carbon atoms to insure, solubility of the compound in mineral oils, Z is an element of the sulfur family and n is an integer of l to 5.

2. A lubricant comprising amajor proportion of a viscous oil and a small amount of an oil-soluble compound selected from the group consisting of cobalt and nickel derivatives of organic compounds having the general formula:

on OH R i. s, l. R

Ar is an aromatic nucleus, R is an alkyl of at least four carbon atoms, 11. is an integer of from 1 to 5 and in which the metal replaces at least part of the hydroxyl hydrogen.

3. A lubricant comprising a major proportion of mineral lubricating oil and a small amount of a compound having the general formula:

of a mineral lubricatingoil and a small amount of a compound having the general formula:

M(CnH2n+1.CBH3.0) 28 where M is a metal of group VIII, series 4 of the Mendeleeif Periodic Table and n is an integer of at least 4, and in which the said sulfur atom (S) is directly linked to each of the two said aryl nuclei (Cal-Ia) and in which the two said oxygen atoms (0) are both linked directly to the said metal atom (M). l I

5. A lubricating comprising a major proportion of a mineral lubricating oil and a small amount of an oil-soluble cobalt salt of compounds having the general formula (CnH2n+i.C6H3.0H)2S, where n is an integer of at least 4.

6; A lubricant comprising a major proportionof a mineral lubricating oil and a small amount of an oil-soluble nickel salt of compounds having the general formula (CnH2n+1.C6H3;OH) 2S, where n is an integer of at least 4.

7. A lubricant comprising a major proportion of a mineral lubricating oil and a small amount of an oil-soluble compound selected from the group consisting of cobalt and nickel salts of alkyl phenol sulfide said alkyl radicals each containing at least four carbon atoms.

8. Lubricant according to claim 7, in which the compound is a cobalt salt of an alkyl phenol sulflde.

9. A lubricant comprising a mineral oil base stock and a small amount of an oil-soluble metal salt whose metal is of group VIII, series 4, of the Mendeleeff Periodic Table of the reaction product of a sulfur halide with an alkylated aryl compound having a hydroxy group attached directly to the aryl nucleus.v

10. An improved mineral oil composition comprising a mineral oil having admixed therewith a minor proportion of an oil miscible sulfide of an alkyl substituted aryl metal oxide in which the oxygen of the metal oxide group is directly attached to the aryl nucleus and inwhich at least two alkyl substituted aryl nuclei are interconnected by at least one atom of sulfur, and in which said metal is a metal of group VIII, series 4, of the Mendeleefi Periodic Table. l

11. An improved mineral oil composition comprising a mineral oil having admixed therewith a minor proportion of. an oil miscible sulfide of an alkyl substituted aryl cobalt oxide in which the oxygen of the cobalt oxide group is directly attached to the aryl nucleus and in which'at least two alkyl substituted aryl nuclei are interconnected by at least one atom of sulfur.

12. An improved mineral oil composition comprising a mineral oil having admixed therewith a. minor proportion ofanoil miscible sulfide of an alkyl substituted aryl nickel oxide in which the oxygen of the nickel oxide group is directly at-' tached to the aryl nucleus and in which at least two alkyl substituted aryl nuclei are interconnected by at least one atom of sulfur.

. 13. A lubricant comprising a mineral lubricating oil and a small amountof an oil-soluble s llfide of a metal alkyl phenolate in which a plurality of phenol groups are attached to a single metal atom and in which said metal is a metal of group VIII, series 4, of the Mendeleeif- Periodic Table.

14. A lubricant composition according to'claim 13 in which the said metal is cobalt.

.15. A lubricant composition accordingto claim 13 in which the said metal is nickel.

16. A lubricating oil composition comprisinga VIII, series 4, of the Mendeleefi Periodic Table.

JOHN G. MCNAB. WALTER T. WA'I HNS, JR.