US2398415A - Mineral oil composition and the like - Google Patents

Description

Patented Apr.16,1946 a a um'rso STATES-PATENT OFFICE,

'- MINERAL OIL COMPOSITION AND THE LIKE George. H. Denison, In, and Paul C. Condit, V

Berkeley, Callfi, assignors, by mesne assignments, to California Research Corporation, San Francisco, Calii'., a corporation of Delaware 1 Application February 22, 1943, Serial No. 476,760-

12 Claims.

This invention relates to the improvement of v hydrocarbon oils by incorporating therein .certain selenium or tellurium compounds.

This application is a continuation-in-part of our copending application "Serial No. 432,040,

filed February 23, 1942, now United States Patent No. 2,346,155, issued April 11, 1944.

performance, and the hard alloys mentioned supra, although preferable tothe older babbitt'.

- bearings from the mechanical standpoint, are

more readily corroded by certain mineral oils,

5 by used oils in which acidic products of oxida- In the art of compounding mineral oil lubricants such as crankcase oils, transmission oils,

turbine oils, greases and the like, there has been accumulated a large body of knowledge conceming the benefits derived from incorporating in such oils small amounts of sulfur compounds. In

particular, benefits have been shown to arise from adding small amounts of monosulfldes (thiocthers), and diand higher polysulfides, which maybe represented by the formulae This is not to say that they are inefiective;- rather, the deficiency arises, in part at least, from the excessive demands put upon lubricants by current machine design and operation, and in part from the fact that such organic sulfides may perform well with one type of oil and poorly with another type of oil.

With regard to machine design and operation, many of the internal combustion engines of today operate at higher temperatures and higher compressions than heretofore with a resultant greater stress upon the lubricating oils and more rapid deterioration of these oils. Thus modern internal combustion engines, more especially those of the Diesel type, become fouled-and develop piston ring sticking more quicklyv than the older engines when lubricated by the same oil.

To complicate matters even further, certain of the bearings in the engines'of today bear greater loads and are ofthe hard alloy type, such as cadmium-silver and copper-lead bearings. The

higher loads on bearings demand better Iubricant eluding in a mineral lubricating oil or the like tion have accumulated, and by the action (believed to be an indirect, catalytic action rather than a direct corrosive action) of certain additives, such as calcium stearate and calcium naphthenate, which are sometimesadded to oils to inhibit piston ring sticking and the likej To meet the demand for better oils, the trend in that branch of the lubricant art which pertains to the use of organic sulfides has been to include with the organic sulfide an activating substance or functional grouping. Thus, asset forth in our copending application Serial No. 350,062, filed August 2, 1940, now United States Patent No. 2,346,153, issued April 11, 1944, by inalong with a dialkyl thioether group, a partial ester of an acid of phosphorus ora salt of such partial ester, for example, calcium cetyi phosphate, a greatl improved performance results.

Thus greatly reduced oxygen absorption and greatly reduced corrosion of copper-lead bearings are observed with oil containing cetyl ethyl thioether and calcium cetylphosphate than with the same oil containing either of these additives alone. As set forth in our copending application- Serial No. 350,063, filed August 2, 1940, now

United States Patent No. 2,346,154, issued April- 11, 1944, even'greater improvement is obtained when a metal phenate such as calcium cetyl phenate is also included in the oil; along with the thioether and phosphorus compound. As set forth in Rosen United States Patents Nos. 2,085,-

045 and 2,216,752, better results are obtained with alkyl phenol sulfides and hydroxy substituted diaryl sulfides than with alkyl aryl sulfides and diary'l sulfides; that is, the functional roup OH-(also amino, .etc.) enhances the potency of the sulfide group.

iii

The general trend in the'development of organic sulfide type inhibitors may, therefore, be

summarized as an adding up or multiplication of 1 functional groups, one being a sulfide type group and the other, which may be present in the same molecule as the sulfide group or in a different molecule, being another type of group or even a second sulfide group, Y

We have found, surprisingly, however, that when the higher dialkyl' selenides or tellurides, those containing at least 8 carbon atoms in one alkyl group and preferably containing at least a carbon atoms in both alkyl groups, are added in small amount to hydrocarbon oils of lubricating viscosity, they exhibit, even alone (without the. aid of activators or functional groups), eilects which are observedwith the corresponding dialkyl sulfides, alkyl aryl sulfides and diary] sulfldes only in combination with activators 'or functional groups.

The following specific examples and the accompanying drawing will serve to illustrate the nature of the results that have been obtained in accordance with the present invention: Example 1.'Dicetyl selenide was prepared stepwise as follows: In the first step, represented by the equation sodium selenide was produced by reactin s'odium and selenium in stoichiometric amounts in liquid ammonia and in the presence of an inert atmosphere (nitrogen). In the second step, represented by the equation cetyl chloride was condensed with the sodium selenide in alcohol solution, also in an atmosphere of nitrogen. In both steps, after the reaction, solvent was removed by evaporation. The product of step'2 was washed free of NaCl with water, and the crude selenide so obtained was observed to stain copper metal black. This tendency can be destroyed and the selenide purified by heating the selenide with copper metal in an inert atmosphere and recrystallizing from petroleum ether. However, it has been found that the eilect of the dialkyl selenides of the invention in blackening copper is of relatively minor significance in practice; hence, the crude product, washed free of NaCl, may be used.

The pure dicetyl selenide is a white, waxy odorless solid crystallizing in small lustrous plates and melting at 123-125 F. It is very soluble in most hydrocarbon solvents, for example petroleum ether, and it is practically insoluble in water and alcohol. These solubility properties are valuable from the standpoint of a lubricant additive since high solubility in hydrocarbon solvents and low solubility in water, together with the low voltry, vol. 28,.page 26 (1936), oxygen being absorbed by the oil under testat 340 F.

The results are tabulated below (Table I) and they are represented graphically in Figure l of the drawing, wherein abscissae represents time and ordinates represent volume of oxygen ab- Oxygen absorbed Time, hours White oil+0.l o

dicetyl dicetyl seleni 3 Example II.-Dic'etyl selenide, dicetyl sulfide and cetyl ethyl sulfide were blended with certain compounded oils knownto be corrosive to copper-lead bearings. Corrosion tests on the various oils were made, with and without added sulfide or selenide. The corrosion tests were carried out as follows: Glass tubes 2 inches in diameter and 20 inches long were immersed in an oil bath, the temperature of which was automatically controlled to within i1 of the 325 F. test temperature. Approximately 300 cc. of oil under test was placed in each tube and air was bubbled through it at therate of 10 liters per hour. Strips of copper-lead bearing metal were placed in the oil. The weight loss of each strip was recorded; Before weighing, each strip was washed in petroleum ether and carefully wiped with a atility of the selenide, render it sufilciently solusoft cotton cloth. The duration of the test was ble in mineral oils and insufiiciently soluble in I '72 hours. The results are given n Table II water to enable the refiner to provide an adebelow;

. Table II 4 fi g i g i Used oil inspection Oil Corrosion inhibitor Viscosity Neutrall- Naphtha 48 increase zation No. insoluble A Nil 23 0 33.3 32.3 0.7 1.19 39- 11.. 1.0% dlcetylsulflde... 2.3 23.2 32.2 7.3 1.39 s A; 0.1% dicetyl 531133133. 11.2 22. 7 30. 0 .7. 3 2. 1s 51 A 0.23% dicetyl 531311103. 3.2 11.2 12.3 3.9 1.10 1 B. Nil 1 30.4 91.1 133.4. 13.3 7.34 12 B 1.07 (113cm sulfide... 37.1 124.1 212.0 9.3 3.13 13.. 0.23 dicetylselenide... 13.7 33.2 43.3 5.3 0.72 g

Nil 34. 1 s3. 3 103. 3 7. 4 1. 33 2 1. cetyl ethyl sulfide 7.9 18.6 21,8 9.8 1.58 14 0.1 dicetylselenide. 8.1 17.6 20.6 3.8 2.27 0 N1 11.0. 30.3 44.0 7.3 1.23 43 1.0%"cetyl ethyl sulfide 4.7 6.4 8.2 9.2 1.52 58 D 0.1% dicetylselenide 0.1 +2.5 1.5 2.1 0.41 (l quate reserve of selenide in an 011 without danger of its being leached out by water or lost through vaporization at elevated temperatures.

The dicetyl selenide thus prepared was dissolved in white oil of medicinal quality in the Oils A, B, C and D referred to in Table II were all compounded oils, the base all being a refined S. A. E. 30 Western oil. In oil A the compounding agent was 0.5% calcium cetyl phenate; in oil 13 the compounding agent was 1.0% of the same amount of 0.1% by weight of the selenide. In phenate; in 011 C the compounding agents were 0.5% calcium cetyl phenate and 0.25% calcium cetyi phosphate, and in oil D the compounding agents were 0.5% sulfurized calcium cetyl phenate and 0.25% calcium cetyl phosphate.

From an inspection of Table II, it is evident that dicetyl selenide is a vastly more effective corrosion inhibitor than dicetyi sulfide and cetyl ethyl sulfide, and on the whole it provides a much better used oil inspection than these sulfides.

Example [IL-A Western s. A. s. so aviation oil, with and without compounding agents. was submitted to test in a Iiauson gasoline engine. The test was carried out as follows: A single cylinder Lauson gasoline spark ignition engine, 2% inch bore and 2% inch stroke, loaded with a three-phase induction generator, was operated under extremely severe conditions designed to develop fully the tendency of the crankcase lubricant to deteriorate with gum formation and piston ring sticking. The engine was operated at mo revolutions per minute, the engine jacket temperature was maintained at 460' 1"., the

crankcase oil temperature was maintained at 220 1". and the engine was operated for hours 'rmm z rm-smgm frennea an. a; so

-Western oil and the same oil compounded with various inhibitors (both of theinvention and not of the invention) were submitted to the 340' F. oxidation test described inExample I. The results are set forth in Tables IV and V below. In these tables the time is given in hours for the absorption of the indicated number of cubic centimeters of oxygen (8. T. P.) by 100 grams of oil. Except where otherwise indicated, the addi- 'tive was dissolved in the oil in the amount of after which the piston condition and the neu tralizsition number of the used oil was deter-- mined. Results are set forth in Table III below:

Table 111 v Percent Bin Nent. Additives ring slot condioi of carbon tion i used oil 1% None 455 40 Stnclr 1. 30 1.6 dicstyl selenide- 51B 100 Free..... 0.24 M! inrised 0., tyl benais-i-OJMK, Us cety phosphate 200 Stuck 1.62 (4) Same oom pounding as (8)+0.5% icetyl seien- (agdg "a 115 0 Free---- 0.2

ms com on as (3)+l.0% dimnryl ien- ,1 ids 7o 0 ..do..... 0.83

P. D. No. (Piston Discoloration l lo.) as used in the table above involves a'caretul-inspection of the piston rcentage of the skirt covered with as being aslight brown gum and a in many cases observed seizure.

skirt 0.1% by weight. The dilauryl seienoxide, being substantially insoluble, was suspended in the oil.' In Figure 2 of the drawing are set forth in graphic form the results obtained with the base oil and with the base oil compounded with several of the additives shown in Tables IV and V. In Figure 2, abscissae represent the time in hours and ordinates represent cubic centimeters of oxygen (8. T. P.) absorbed per grams of oil.

Table IV Oxygen absorbed by base oil plus- Dicetyl Dilsnryl selenide disclenide Didscyl. selenido Table V Oxygen absorbed by base oil plus- Bis an (p-nyg? Dicetyl chloro'ostyl) droxycetyl) 23%;;

Bahama telluride ,seienide selenide we L (0.15%) (04am) The curves of more 2 reveal strikingly the unusual performance of the higher dialkyl selenides of the present invention.

Example V.--'Ihe oxidation inhibiting eflect of minute amountsof a dialkyl selenide or the present invention is shown in Table VI below. This tabiesets forth the results of a test on a highly refined" white 'oil 'of extremely small amounts of dicetyl s'elenide. The was carried out as follows: 25 cubic centimeters of oil were placed in a cylindrical glass cell 4% inch' long by 1% inch diameter. This cell was connected with a manometer and was immersed in an oil bath maintained at 275 F. The cell was disposed so that its axis was at a slight angle with the horizontal, and it was connected with an agitator (a windshield wiper motor) in such a manner that operation of the motor caused the cell to rock in the bath. The cell and manometer connection were freed of air and filled with oxygen prior to immersion in the oil bath. The instant of immersion was taken as zero time and agitation was commenced at this time. Manometer readings were taken until a pressure drop, due to absorption of oxy en, of locentimeters ofmercury was recorded. The square root of pressure drop was then plotted against time and the intercept of the resulting curve with the time axis was taken as the inhibition period.

Results are set-forth in Table VI below:

ExampleVL-Oils A, B and C, with and without various selenides and a teiluride, were submitted to the Aluminum dish test." This test, which is very severe from the standpoint of gum formation, was carried out as follows: A weighed sample of oil (about 5 drops) was placed in an aluminum dish 2 inches in diameter which is flat on its lower face and slightly concave on its upper face, the dish having been thoroughly cleaned and dried before putting in the oil. The dish was then placed on an electric hot plate, the surface temperature of which was adjusted to the desired value. The dish was left on the hot plate for 20 minutes and was then removed and cooled to room temperature. The dish and deposit were then washed free of oil with petroleum ether and the residual gum was determined. The gum is expressed as percentage by weight of the original oil. 011 A was a Western SAE 60 aviation oil. Oil B was the same oil containing 0.375% of so]. furized calcium cetyl phenate and 0.125% of calcium cetyl phosphate. Oil C was a Western SAE 30 oil containing 0.5% of sulfurized calcium cetyl phenate and 0.25% of calcium cetyl phosphatej Table VII I Gum Gum Gum Oil Additive formed formed formed V at 550 F. at 600 F. at 550 F.

V A Nil... 3.8 '16.7. 19.8

A 0.25% dioetyl selenide.-." 2. 5 -1l. 18.2

A 0.50% dicetyi selenide. l. 2 ,8. 7 i7. 3

A 1.0% dicetyi selenide 0 4. 4 l3. 6

A 2.0% dieetyi selenide 0 0. 52 10.

B Nil B. 72 13. 5 l9. 8 B 2.0'7 diundecyl selenide... 0. 79 8. 1 13.05

B 2. o dilauryi selenide-.." 0.85 6. 7 i2. 8

B 2.0% ditetradecyl selenide. 0. 35 7. 5 10. 4 B 2.0% dicetyl selenide--... 0. 01 0.37 8. 8

B 2.07 dihe tadecylselenide. 0 5. 7 14. 9'

B. l. dice yl diseienide 0 1.8 8.6

B. 2.0% dicetyl te1luride.... 0- 0 2. l

C 1.0% diparaflin selenide-.- 0 0.3 4. i

C 2.0% dilauryl diselenide-.. 0. 2 3. 2

It is known that a thioether of the type represented by dicetyl sulfide is not a very potent oxidation inhibitor if it is the only inhibitor present in an oil, but if an activator" such as calcium cetyl phosphate be present, the combination forms a potent oxidation inhibitor. been found, surprisingly, that the dialkyl selenides of the present invention do not behave in the same manner; they are potent inhibitors when acting alone, but their behavior in the presence of calcium cetyl phosphate and the like is very different from the behavior of thedialkyl sulfides in the presence of calcium cetyl phosphate and the like. This is illustrated by the data in Tables VIII and IX below, taken from oxidator tests the same as described in Example I.

- Table VIII (no iron present) Table VIII refers to oxidation tests carried out in the absence of iron while Table IX refers to the same oxidation tests carried out inthe presence of iron. It will be seen that inthe absence of iron (Table VIJI), dicetyl selenide was more eflective in the absence of calcium cetyl phosphate than in its presence, whereas from Table IX (in the presence of iron) it will be seen that dilauryl selenide was, more effective in the presence of calcium cetyl phosphate than in its absence. Since iron is always present under conditions of actual use, as in the crankcase and cyl- It has I represented by the formula same as that described in Example II. As shown by the data of the table, the diallryl selenides cooperate with the indicated compounding agents very much better than do the diallryl sulone. Wheren is 2 or more, and branched chain groups are comprehended by (X) 1.. The groups R and R1 .may be not only straight and branched chain saturated alkyl In the specific examples and in the tables above are mentioned varioussulfides, selenides, a tellurideand a selenoxide. These are listed below and are identified as to structure or manner or preparation.

O Hge.CH.CHr-5e-CH9.CH.CiiHn 1 1 Bis (B-hydroxy cetyl) selcnide I Ou n-CH.CHsSCH|.CH.CitHn Miscellaneous Monoselenides lselenide, CH SeCtH eilyl selenidc CieHtrkCsHt Dibenzyl selenide, Ct OHz-Se-Clhfldi, iselenides Dileur l diselenide, 'nCnH:5(Se)rCmH2s'n Dicety diselenide, 'n'-C1sHu-(Se) C|slIn-n Monotellurides Dicetyl telluride, n-CmHaaSeCmHsa'Il Miscellaneous selenides Diparaiiln seleniderpre fin wax with NagSe.

ed by condensing chlorinated -paral ost probably a mixture oi compounds corresponding to the formula R-SeR, where R is a higher alkyl radical. Dilauryl selenoxide,

n-Qfiln-Se-CnlIu-m 7 otherwise specified.

As stated, dialkyl selenides and dialkyltellurides containing at least 8 carbon atoms in an alml group, preferably containing at least 8 carin accordance with the invention. These may be where 1-01 or 0H, and the "his [p-chloro (or hydroxy) cotyl] solenide" may be a mixture of compounds.

chain unsaturated aliphatic groups CnH'm-l, C1|H2n3, etc., and also cycloalkyl or cycloaliphatic groups. That is, the groups attached to selenium and tellurium in the compounding agents of the present invention, may be saturated, unsaturated or cyclic aliphatic groups. Also, the groups R and R1 may be substituted by aromatic groups, such as the phenyl, hydroxy phenyl andamino phenyl groups, provided such groups are spaced at least one carbon atom from the group (Xn). Polar groups, such as chlorine, bromine, hydroxyl, ether, keto, amino, free carboxyl, metallo carboxyl, carboxy ester, mercapto, mercaptide, mono--, di and polysulfide, etc'., may be substi tuted in the groups R and R1 of the selenides and tellurides of the present invention. Two or more selenlde or telluride groups (X); may be bonatoms in each alkyl group, may be employed present in the molecule.

The following specific examples of selenides and, tellurides, together with those specifically mentioned hereinabove, will illustrate the selenium and tellurium compounds or the present invention: decyl methyl monoselenide, cetyl ethyl monoselenide, octyl decyl monoselenide, di-elcosyl both straight chain fides. 5 groups CnH2n+1, but also straight and branched Table X Wt. loss Gil-Pb strips W8 h Additives larges so 3? 3 24 hrs. 48 hrs. 72 hrs.

0.5a (lace 1 swimwear Ca cety l phosphate 34.1 as. a 108.3 1.4 1.03 28 0.5 Csceglghenateigm Cacetylphosphate+l% cetyletliyl'suliid -7.9 18.6 21.8 as 1.58 14 0.6 On cetyl henate .25 0a octyl bospbate-i-0.2% 4-2 2 10-6 2.0 0.96 0 0.5 aullurizecfca octyl phenate-l-OJIS'iCa octyl pnos hate ll. 0 30. 5 44.0 7. 6 1. 28 45 0.5 sullurised Ca cetyl phanate+0.25 Ca cetyl phosp ate+1% octyl ethyl sulfide.. 4. 7 6.4 8. 2 9. 2 1.62 58 0.6 a euliurized Cacetyl plienate+0.25 a Cacetylphospbate+0.l% cetyl selenidc... 0. 1 +2. 5 1.5 2. l 0. 41 o monoselenide; dioctyl diselenide, didecyl disele-' nide, diheptadecyl diselenide, dieicosyi diselenide; decyl methyl monotelluride, ctyl ethyl monotelluride, octyl decyl monotelluride, didecyl monotelluride, diundecyl monotelluride, dilauryl'monotelluride, ditetradecyl monotelluride, dicetyl monotelluride, diheptadecyl monotelluride, 'dieicosyl monotelluride; dioctyl ditelluride, didecyl ditelluride, dilauryl ditelluride, dicetyl ditelluride; and the various monoand polyselenides and monoand polytellurides'prepared by reacting sodium or other alkali metal mono- ,or polyselenides or monoor polytellurides with halogenated, e. g., chlorinated. hydrocarbons, such as decyl chloride, dodecyl chloride, tetradecyl chloride, cetyl chloride, heptadecyl chloride, eicosyl chloride, chlorinated lubricating oil and chlorinated wax. I

The selenides are preferred to the tellurides, because they are more stable and more easily prepared. However, the tellurides are highly efl'ective as oil stabilizers and may be preferred in certain cases.

condensing a metal selenide, polyselenide, telluride or polytelluride with a chlorinated or bromi- Mixtures of selenides or tellurides are suitable, such as those prepared by.

Suitable methods of preparing the dialkyl seleiiides and tellurides of the invention are as folows:

1 (1) From aliphatic halides and a. metal selenide, telluride, polyselenide or polytelluride, by condensation in an inert solvent such as ethyl alcohol. This method is particularly suitable for the preparation of pure, simple selenides and tellurides such as dicetyl selenide and dicetyl telluride, and for the preparation of mixtures of selenides and/or tellurides, as from chlorinated wax.

(2) From the seleno and telluro analogues of the mercaptans; that is, from compounds of the type RSeH and RTeH, where R. is an aliphatic group. The compound RSeH or RTeH, which may be termed a seleno mercaptan or a "telluro mercaptan, is converted to a metal seleno mercaptide" or metal telluro mercaptide, which is then condensed with a halogenated hydrocarbon, such as oetyl chloride, or a halogenated'mixture of hydrocarbons, such as chlorinated wax,

in the same manner as-the halogenated hydrocarbons are condensed with metal selenides or tellurides. This method is especially suited to the preparation of mixed selenides or tellurides, such as cetyl ethyl selenide and cetyl ethyl telluride; for example, as follows:

t be readily and economically prepared by the "following series of reactions:

In the above equation, M represents an alkali metal, preferably potassium; R represents an allphatic group; and X represents a replaceable n e ative atom or radical, preferably chlorine. In carrying out this process, reaction (a) may be carried out in aqueous solution, reaction (b) may be carried out in ethyl alcohol, and reaction (c) is carried out by reacting the alkyl selenocyanate with caustic alkali in aqueous alcohol. This method does not yield as desirable a product, from the standpoint of lubricant additives, with chlorinated wax as it yields 'with some of the lower, purer alkyl chlorides, such as lauryl chloride and cetyl chloride.

(4) Selenium is dissolved in strong aqueous or alcoholic caustic soda or caustic potash solution to yield a mixture (in solution) oi alkali metal selenides, polyselenides and selenites, poosibly also other selenium compounds. It has been found that when this mixture is heated with a halogenated hydrocarbon or mixture of hydrocarbons, such as laurylchloride or chlorinated wax, the product, comprising a complex mixture oil-selenides and probablyincluding monoand diselenides, perhaps also higher polyselenides, is an excellent lubricant additive.

As stated hereinabove, the selenides and tellurides oi. the present invention are not only compatible with but arealso highly cooperative with other types of additives in hydrocarbon oils. Thus with metal salts of organo substituted phosphates in tho-presence oi? iron, the selenides and tellurides oi the present invention yield a highly beneficial combination eiiect, and with metal salts of phenols, especially the poly'valent metal salts or the higher alkyl phenols, 'oil stabil.

ity results. Other types of additives with which the selenides and tellurides of the present invention may be used include the metal salts of organo substituted acids of boron, sulfur, and arsonic; the metal salts of carboxylic acids such as aryl carboxylic acids, fatty acids and polar sub-' stituted aliphatic mono-"and polycarboxylic acids I (calcium cetyl oxalate, calcium cetyl citrate, magnesium alphahydroxy stearate, magnesium tartrate and the like). The additives of the present invention may be used in hydrocarbon oils in conjunction with sulionates, such as the metal (calcium, magnesium, zinc, cadmium, aluminum, etc.)

salts of aryl sulfonic acids of the "Nacconol" type (higher alkyl aryl sulfonic acids) or with petroleum sulfonates, such as calcium, magnesium, zinc, cadmium, or aluminum petroleum sulf0 nates.

The selenides and tellurides of the present invention are particularly useful in steam turbine lubricating oils in conjunction with rust inlnbitors, especially the higher alkyl acid esters of polybasic aliphatic acids such as lauryl acid maleate, monoor'dicetyl citrate and the like.

The additives ofthe present invention, as seen from the above examples, in particular, Example V, are effective in amounts as low as 0.000]. per cent. Ordinarily concentrations of about 0.1 to 2 per 'centwill be used but larger and smaller amounts may be used. Amounts greatly in excess of 5% are ordinarily considered unnecessary except in forming a concentrate of the selenide oils and greases made therefrom. They may be used not only in lubricating oils for internal combustion engines, but also in transmission oils, turbine oils,-cutting oils, spray oils and elsewhere.

As for types or oil, the additives of the present invention may be used in parafllnic, mixed base and naphthenic petroleum lubricating oils; in oils of low or high viscosity; in oils resulting from olefin polymerization or the reduction ordistillation of coal or coal products, oils from the hydrogenation of oxides of carbon, animal and vegetable oils, and synthetic lubricants such as amyl naphthalene. They may also be used to stabilize other organic products, such as fats, fatty oils, etc., against deterioration.

We claim:

1. A composition of matter, comprising an oil and asmall amount, sufilcient to stabilize the oil,

of a compound of the type R-(X) n-R1 where R and R1 are like or unlikealiphatic radicals at least one of which contains not less than 8 carbon atoms, X is an element selected from the selenium.

3. The composition of claim 1, wherein R and R1 each contains at least 8 carbon atoms.

4'. A composition of matter, comprising a hydrocarbon oil of lubricating viscosity and a small amount, sufiicient to improve the oil, of a compound selected from the group consisting of dialkyl monoselenides and dialkyl diseienides where R.

than 8 carbon atoms wherein at least one alkyl group contains not less than 8 carbon atoms.

5. The composition of claim 4, wherein said compound is a monoselenide.

6. A- compounded mineral lubricating oil com-,

prising a small amount, sufllcient to stabilize the oil, of aselenide of the type I R-(Se) -121 and R1 are like or unlike open chain groups each of which contains not less and n has the value of 1 aliphatic or 21 a 7. A composition of matter, comprising an organic substance which tends to deteriorate in the presence of oxygen, and a stabilizing amount a compound of the type where R and R1 are like or unlike aliphatic radicals at least one of which contains not less than 8 carbon'atoms, n has a value or 1 or 2, and X is selected from the group consisting of selenium and tellurlum.

8. A compounded lubricating oil, comprising a petroleum oil or lubricating viscosity and about a to by weight based on finished oil of di-' cetyl monoselenida v paramn. monoselenide.

9. A compounded lubricating oil, comprising a petroleum oil of lubricating viscosityand about 0.1 to 2% by weight based on finished oil of dilauryl 'monoselenide. V

10. A compounded lubricating oil, comprising a petroleum oil of lubricating viscosity and about 0.1 to 2% by weight based on finished oil of di- 11. A composition .of matter useful for blending with hydrocarbon oils, comprising a concentrated dispersion in viscous hydrocarbon oil of v a; compound corresponding to the type dialkyl monoselenide containing eight to twenty carbon atoms in each alkyl group.

GEORGE E. nnmson, as. PAUL c. coumn lubricating oil, comprising

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