US2409686A - Compounded lubricating oil - Google Patents

Description

s2-40ui21 Patented Oct. 22, 1946 Search Room COMPOUNDED LUBRICATING OIL John G. McNab, Cranford; and Di-lworth T. Rogers, Plainfield, N. J assignors to Standard Oil Development Cor Delaware pany, a corporation of No Drawing. Application July 7, 1943, Serial No. 493,734

15 Claims. 1

This invention relates to lubricants and. other organic. materials subject to deterioration in the presence of oxygen, and it relates more particularly to mineral lubricating oil compositions for use as crankcase lubricants for. internal combustion engines and to addition agents suitable for retarding the deterioration of such oilsv and for improving other properties of the same.

It i known that the addition of certain types of metal organic compounds to lubricating oils improves various properties thereof, such as their oiliness characteristics and their detergent action in engines, particularly manifested in the maintenance of ,a clean engine condition during operation. Various metal compounds which have been used for such purposes include. the metal derivatives of such organic compounds as fatty acids, naphthenic acids, alcohols, phenols and ketones. However, these various metal compounds generally have the disadvantage of tending to corrode alloy bearings, such as those of cadmium-silver and copper-lead, now so widely used in automotive engines; and this is especially true in engines which operate at relatively high speeds and high temperatures. It is an object of the present invention to provide a new class of addition agents for oilswhich are to be used as crankcase lubricants for internal combustion engines and which exhibit the desirable properties of promoting general engine cleanliness, reducing ring sticking,

piston. skirt varnish formation and the like, and which not only do not exhibit the corrosion promoting tendencies characteristic of the above metal compounds, but also inhibit the corrosiveness of oils to which they are added.

The new classof products-which have now been found to be highly satisfactory as addition agents are the products obtained by the reaction of the elements sulfur and phosphorus with certain metal phenates and thiophenates, more specifically, the calcium, barium, strontium, magnesium, and zinc phenates and thiophenates containing as a substituent in the aromatic nucleus an alkyl group having at least 5 carbon atoms. It has been found that such products are unusually satisfactory in inhibiting bearing corrosion, in being stable in the presence of water, and in being adaptable to use with a wide variety of lubricating oil base stocks. The elements sulfur and phosphorus may be introduced into the phenate molecule by products in lubricating oil compositions.

reacting the latter with both elemental sulfur and elemental phosphorus, or by reacting the same with a sulfide of phosphorus. The reaction may generally be brought about in a solution of lubrieating oil or other petroleum oil, whereby concentrates may be prepared which-may be convenient- 1y stored or shipped and added to lubricating oils when required.

The new sulfur and phosphorus containing compositions herein described are also useful as antioxidants and for other purposes when incorporated in organic materials other than lubricating oils, as will be more fully explained hereinafter, and in many cases it is not necessary to have alkyl groups present to impart suflicient solubility. The invention includes the reaction products of phosphorus sulfides with compounds analogous to the phenates and thiophenates, but containing selenium and tellurium in place of oxygen. or sulfur, and with compounds in which aromatic nuclei other than benzene nuclei are present.

In a copending application we have described the preparation of reaction products of elemental sulfur with metal phenates and the use of such It was there shown that the sulfur atoms were linked directly to the metal atoms in the molecules of the reaction product. It is believed that the same type of reaction occurs when metal phenates are treated with phosphorus sulfides or with phosphorus and sulfur, giving compounds in which the phosphorus and sulfur atoms are linked together in the molecule to form a group which is attached directly to the metal atom, probably through secondary valences.

One basis for this belief is that. when these products are treated with hydrochloric acid they lose a. large proportion of their phosphorus content, an appreciable amount of sulfur and practically all of the metal. On the other hand, when a metal organo thiop hosphate is similarly treated, only attainment of sulfur andsubstantially no phosphorus is lost from the compound.

Some of the more preferred products to housed in accordance with the present invention are those obtained by reaction of a sulfide of phosphorus or of the elements sulfur and phosphorus with the following compounds:

Barium tertiary octyl phenate Calcium tertiary octyl phenate Barium diamyl phenate Barium cetyl phenate Zinc isohexadecyl phenate Calcium salt of petroleum phenols Barium salt of wax-alkylated phenol Magnesium salt of octadecyl cresol Barium salt of phenol alkylated with refinery olefin polymers The invention includes the reaction products of phosphorus and sulfur or sulfides of phosphorus with not only the normal phenates and thiophenates and the like, but the basic metal phenates and thiophenates as well. In a normal phenate of a divalent metal the ratio of metal to phenol is 1 to 2 as in the following formula:

In a basic metal phenate the ratio of metal to phenol may be 2 to 2 or even 3 to 2. In the case of a 2 to 2 ratio the formula may be These basic phenates are formed, for example, by reacting phenols with more than the amount of metallic oxide or hydroxide necessary to form the normal phenates. Reaction products of phosphorus sulfides with basic metal alkyl phenates are particularly useful in extreme pressure lubricants and are advantageous in motor oils prepared from naphthenic base stocks.

It is also intended to include within the scope of this invention products obtained by the reaction of phosphorus sulfides with metal salts of alkylated phenol sulfides and with metal salts of alkylated hydroxy carboxylic acids, for example, barium tert.-octyl phenol sulfide or the barium phenate-zinc carboxylate of lauryl salicylic acid.

It is likewise often practical to apply this reaction with phosphorus sulfides to other organic compounds containing the OM or SM group, such as the metal alcoholates, mercaptides or ketonates; for example, calcium octadecylate, barium salts of wax alcohols, etc., and to use the products formed as additives for mineral oil lubricants.

The new class of addition agents employed in accordance with the present invention may be defined in its broadest scope as the reaction products of the elements sulfur and phosphorus with a compound having the formula the periodic table, the most important being calcium, barium, strontium, magnesium and zinc, although for some purposes corresponding compounds containing tin, lead, cobalt or nickel will alsobe found to be desirable. T in the formula represents either a hydroxyl group or the group tached to the nucleus, the total number of car- (OM) nXAI' where R represents at least one alkyl radical atbon atoms in all of such alkyl radicals being at least 5 when the compound is to be dissolved in hydrocarbon oils, other symbols having the meanings given above. It should be understood that the above general formulas include compounds in which various substituent atoms or groups may be attached to the aromatic nucleus, such as alkyl, aryl, carboxyl, hydroxyl, alkoxy, sulfhydryl, nitro, ester, keto, amino, aldehydo, chlormethyl, aminomethyl, alkyl thiomethyl, alkyl xantho methyl, metal substituted carboxyl, metal substituted hydroxyl 0r sulfhydryl groups, halogen atoms, etc. Alkyl radicals attached to the nucleus may have a total of 5 to 12 carbon atoms in all of such groups, but in some cases as many as 16 to 20 or more carbon atoms in a single group or a plurality of groups may be preferred. If more than one alkyl group is present in a single molecule, whether or not attached to the same aryl nucleus, such groups may be alike or different. Also included within the class of metal derivatives defined above are the metal salts of phenol sulfides and alkylated phenol sulfides.

Suitable alkylated phenols for use in the present invention may be prepared by alkylating phenol, cresol,naphtho1 or other phenolic compounds with such alkylating agents as alcohols, alkyl halides, alkyl phosphates, olefins, and the like, with the aid of catalysts such as metal halides, hy-

drochloric acid, hydrofluoric acid, sulfuric acid,

phosphoric acid, activated clay, etc. Conveniently, olefinic material such as petroleum refinery gases, containing mixtures of olefins, may be used, or preferably individual olefins may be em- I ployed, such as butene, amylene or an olefin polymer, such as diisobutylene or triisobutylene. High molecular weight alkylated phenols may also be used, for example, those prepared by condensing phenols with chlorinated petrolatum or chlorinated paraffin. wax, or with a chlorinated kerosene or gas oil.. Naturally occurring phenols, such .as those obtained by alkaline extraction of certain petroleum stocks or those obtained from cashew nut shell liquid or from other vegetable sources may likewise be used. Halogenated or nitrated phenols will also find applicationin this invention, particularly if the final additive is to be employed in extreme pressure lubricants.

One class of alkyl phenols which are particularly preferred are those which have been prepared by alkylation of phenol with an olefin polymer such as diisobutylene or a refinery butene polymer oil. Alkylation of phenol with about anv equal molar proportion of diisobutylene gives para-tert.-octyl phenol, also known as diisobutyl phenol or tetramethyl butyl phenol. This phenolic material is especially desirable because of its ease of preparation and because products made from it are highly satisfactory for the present invention. In many instances, however, a higher degree of alkylation may be advantageous and for this reason the phenol may be alkylated with as muchas two molecular equivalents of diiso- 252. Dlillfilhllliltld. watch H! butylene. to give, under proper conditions, essentially di-tert.-octyl phenol; or it. may be; alkylated. with. other olefin polymers such as; triisobutylene, other isobutylene polymers, or, a normal butene polymen. It should be understood'that in many-cases thea'lkylation products maybe mix.- tures of various compounds rather than entirely one specific alkyl phenol and that it is intended to use suchmixtures in practicing this invention.

For converting the phenolic materialsto metal phenates any convenient and effective means may be employed. For example, sodium or potassium salts may first be formed by reaction with NaOH or KOH and those salts then. converted to the desired divalent metal salts by double decomposition. Another method which may be used is the reaction of an alcoholate of the desired metal with the alkylated phenol. When possible, of course, the most convenient method is to react the alkylated phenol directly with the oxide or hydroxide of the desired metal. Thus, the barium salts canbe prepared directly byadding'barium hydroxide to a mineral oil so lution of the alkyl phenol at elevated temperature.

Inaccordance with the present invention, the metallic phenate or other analogous metallic derivative of an aromatic hydroxy or mercapto compound is caused to react with the elements sulfur and phosphorus. This maybe accomplished by adding a mixture of thesubstances in elementary form, or first one-element and then the other, to the heated metallic compound, or by adding a sulfide of phosphorus, such as P2S5, P483, P4S7, etc. or the like, or by treating with both sulfur and/or phosphorus and a sulfide of phosphorus, or by treating with any other substance or substances containing-essentially only the elements sulfur and phosphorus. The phosphorus may be used either in the white (yellow) or red allotropic form, and sulfur may likewise be used in any of its allotropic forms.

However, it is ordinarily more convenient to use a sulfidfie of phosphorus; In carrying out the reactions described above the proportions of phosphorus sulfide and metalv phenate. are so chosen that from 0.5 to 2 atoms of phosphorus are reacted with one atom of polyvalent metal, the preferred ratio. being within the limits of about 0.8 to 1.2 atoms of phosphorus per atom of metal. Depending upon which sulfide of phosphorus is selected, the atomic ratio of sulfur to metal will then lie within the limits of about 1.5 to- 1 to d to 1, preferably from about 2 to 1 to 3 to 1. These preferred ratios give the products the optimum content of phosphorus and sulfur to impart to them the maximum amount of inhibiting power. In general, these same ratios will be employed also when the reaction. is conducted with elemental sulfur and, elementalphosphorus.

Although the reaction can be brought about by fusing the metal phenate with phosphorus and sulfur, or with a phosphorus sulfide, it is more convenient to carry out the reaction with the aidv of solvents, particularly high boiling hydrocarbon solvents, such as xylol or a petroleum fraction. A particularly preferred reaction medium is a lubricating oil fraction, since the final reaction products can thus be obtained as a min eral oil concentrate of the desired additive, which may be conveniently shipped or stored as such and then readily blended with a lubricating oil base stock in the desired concentration to form a finished lubricating oil blend.

The additives may generally be prepared by dissolving an alkylated phenol in a mineral oil or other suitable solvent and treating the same with a metal hydroxide, e. g., Ba(OH') 2.8H2O, at to 230 C., preferably at 150 to 190 C. After a further period of heating, free sulfur and free phosphorus, or asulfide of phosphorus, or other mixture of ,the elements, is added, heating being. continued preferably at to C. to complete the reaction. The period of heating will generally be from about 10 minutes to an hour, although in somecases longer periods may be required. When the material will no longer stain a strip of copper immersed in it, the reaction is considered complete. The product is then filtered, giving a concentrate of the desired additive.

If a calcium salt is to be prepared, a less direct action is preferred, since the reaction of alkylated phenols with calcium oxide or hydroxide does not proceed as readily as in the case of barium compounds. Calcium alkyl phenates are preferably prepared by reacting alkylphenols with calcium methylate or other calcium alcoholate.

It has been found that good results are obtained when preparing theseadditives in mineral oil if a minor proportion of a higher alcohol, such as stearyl', lauryl, cetyl, wo-ol fat alcohol or the like is added to the reaction mixture in which the compounds of the present invention are prepared. This alcohol reduces foaming during the process and acts as an auxiliary solvent for the final product. The best results are obtained by adding a sufiicient quantity of alcohol to give a concentration of about 3% to about 15% of the final additive concentrate.

Although it is known that sulfides of phosphorus will react with alcohols, such reaction is relatively slow under the preferred conditions of the present invention, whereas the reaction with the metal phenates is extremely rapid, so that by the time the latter reaction has been completed there will have been relatively little or no reaction between the higher alcohol and the sulfide of phosphorus. Hence substantially all of the alcohol is present as such in the final product.

It has also been found that products of better oil solubility can often be obtained when carrying out the reaction with sulfur and phosphorus in the presence of a small proportion of an olefinic material, such as a tetraisobutylene, cracked gas or an unsaturated alcohol.

Generally, the additives of. the present invention are most advantageously blended with lubricating oil base stocks in concentrations between the approximate limits of 0.02% and 5.0% and preferably from 0.1% to 2.0%, although larger amounts may be used for some purposes. The exact amount of addition agent required for maximum improvement depends to. a certain extent on the particular products used, the nature of the lubricating oil base stock and the general operating conditions of the engine in which the lubricant is to be employed. This same general range of concentration will also be effective when the additives are to be used in greases and in extreme pressure lubricants, although in the latter instance greater amounts may also be employed.

As has been pointed out elsewhere in this specification, it is often convenient to prepare concentrates of the additives in oil, containing, say, 25-to75% of effective-addition agent, the'concentrate later being added to a suitable lubricating oil base stock to give a finished blend containing the desired percentage-ofadditive. Thus, when usinga 40% concentrate, 2.5% of thi ma- 7 terial may be blended with a suitable base stock to give a finished oil containing 1% of effective addition agent.

In the following examples are described Various preparations of products in accordance with this invention and the results obtained on testing the same in various lubricating oil'blends. It is to. be understood that these examples, given for illustrative purposes only, are not to be construed as limiting the scope of the invention in any way.

EXAMPLE 1 A mixture of 618 parts by weight of tert.-octyl phenol (prepared by reacting diisobutylene with phenol in the presence of SnCh and HCl catalysts at to 85 C.), 240 parts of commercial stearyl alcohol and 1200 parts of mineral oil (a solvent extracted Mid-Continent parafiinic oil of 52 seconds Sayboltviscosity at 210 F.) was heated to 120 C. Then over a two hour period 632 parts of barium hydroxide (Ba(OIDaSHzO) were added. During the reaction a stream of nitrogen gas was passed through the mixture to minimize oxidation. After an additional one-half hour of heating at the same temperature, 256 parts of phosphorus pentasulfide (P285) were added in two approximately equal portions over a ten minute period. The temperature rose immediately to 130 C. and was held at 120 to 130 C. for one hour. The reaction product was then filtered, using Hyflo filter aid. The filtered concentrate was found to have the following analysis:

, Per cent Barium 6.99 Sulfur 4.97 Phosphorus 1.69

The metal content of the product obtained in the above example was lower than that theoretically expected for the proportion of reactants used. This was found to be the result of using an old sample of barium hydroxide octahydrate which had absorbed large quantities of carbon dioxide, forming barium carbonate, which is not suitable for this type of reaction. In subsequent preparations it was found that when using the same proportions of reactants as in Example 1 but employing fresh Ba(OH) .8I-I2O, the product obtained had a higher metal content than that 'of Example 1, or conversely, a product having the same metal content as that of Example 1 could be prepared by using less of the fresh barium hydroxide octahydrate.

EXAMPLE 2 Per cent Barium 6.40 Sulfur 2.85 Phosphorus 2.06

EXAMPLE 3 The procedure of Example 2 was repeated using Lthe same proportions of reactants and the same Per cent Barium 6.95 Sulfur 4.83 Phosphorus 2.10

EXAMPLE 4 The distinguishing feature of this preparation is that a basic barium phenate was used in the reaction.

A mixture of 412 parts of water-washed ptert.- octyl phenol (prepared as in Example 1), 203 parts of commercial stearyl alcohol and 1015 parts of the mineral oil used in Example 1 was heated to 150 C. 625 parts of Ba(OH) 2.8H2O were added over 1 /2 hours and the temperature raised to 190 C. for 1 hour and then cooled to C. 266 parts of P2S5 were added and the temperature raised to C; for one hour and the product filtered, yielding an additive concentrate which contained:

Per cent Barium 9.69 Sulfur 5.57 Phosphorus 3.38

EXAMPLE 5 To reduce the tendency of the product of Example 1 to stain copper a portion was heated for one hour in a stream of air at 150 to -C., the treatment causing it to darken in color and to become more viscous although clearer in appearance. The resulting product contained 4.35% sulfur and 2.14% phosphorus.

EXAMPLE 6 A mixture of 618 parts of water-washed p-tert.- octyl phenol (prepared as in Example 1), 240 parts of commercial stearyl alcohol, and 1200 parts of the mineral oil used in Example 1 was heated to 150 C. Then over a 1 /2 hour period 465 parts of Ba(OPDzBHzO were added. The temperature was then raised to C. for one hour, then cooled to 130 C. for 15 minutes while 266 parts of P2S5 were added. The temperature was again raised to 180 to C. for an additional hour and the reaction product filtered. The resulting additive concentrate had the following analysis:

EXAMPLE 7 A mixture of 618 parts of p-tert.-octyl phenol (prepared as in Example 1), 225 parts of stearyl alcohol, and 1123 parts of the mineral oil used in Example 1 was heated to 150 C. Then 450 parts of barium hydroxide (Ba(OH) 2.81120) were added over a 90 minute period. The temperature was then raised to 170 C. for one hour. 70 parts of lump sulfur were incorporated and the temperature was raised to 190 C. for an additional hour and then cooled to 130 C. After addition of 200 parts of P2S5 the temperature was held at 130 C. for another hour and the reaction prodliiilioll l NW3.

EXAMPLE 8 In the production of secondary butyl alcohol from refinery butenes the latter are contacted with 75% to 90% sulfuric acid at 20 to 30 C. to form butyl sulfuric esters which are subsequently hydrolyzed to form the alcohol. During contact with the sulfuric acid some of the butenes polymerize and form what is known as a polymer oil. Since the refinery butene feed stock may contain 40-50% of olefim'c material in which, in addition to n-butene, 1 to 2% of butadiene, 1 to 3% of isobutene and 1 to 2% of the dimer and/or trimer of isobutene may be present, the exact nature of the polymer oil obtained is not certain. However, it can reasonably be assumed that it comprises a mixture of polymers and copolymers of these various olefins. For the alkylation of phenol to form products useful for preparing materials of the present invention the butene polymer is steam distilled up to 400 F. and the bottoms, boiling essentially from 400 to 650 F., used as the alkylating material. A mixture of 100 parts of phenol and about 240 parts of the polymer oil fraction is saturated with hydrogen chloride at 80 and 130 F. and parts of aluminum chloride are added over a half hour period with stirring. Stirring is continued for an additional 1 /2 hours at 120 F. and the product is water Washed and then stripped of unreacted material by distilling to 270 F. with nitrogen and then up to 400 F. with steam. The desired phenol remains as the bottoms from this distillation. The product contains alkyl groups having an average of 16 to 20 carbon atoms per molecule.

EXAMPLE 9 (Ba(OI-I) 2.8H2O) over a one hour period after which the temperature was raised to 170 C. for an additional hour. After cooling the mixture to 120 C., 150

parts of PzSs were added and the temperature maintained at 120 to 130 C. for one hour and the product filtered. The additive concentrate had the following analysis:

Per cent- Barium 5.49 Sulfur 3.95 Phosphorus 1.76

EXAMPLE 10 To reduce the copper staining tendency of the product of Example 9 a portion was heated for one hour at 210 C. in a stream of nitrogen. The product had the analysis:

Per cent Barium 5.49 Sulfur 3.59

Phosphor us 1.96

EXAMPLE. 11

A mixture,o 578 parts of o -2o alkylated phenol (prepared as in-Example 8 and 1080 parts of a refined mineral lubricating oil' of 52 seconds- Saybolt viscosity (210 F.) was heated to 180 C. and 260 parts of Ba(-OH)2 .8H2O added thereto. The reaction product was cooled vto 150 C. and filtered, yielding 'a-40% concentrate ofthe barium alkyl phenate in oil. It contained 6.05% barium.

EXAMPLE 12 over a period of 5 to 10 minutes, this step causing the temperature to rise to 196C. The temperature was then lowered to 190 C. and heating was continued until a sample withdrawn from the reaction vessel was found to be relatively non-staining to a copper test strip. The reaction mixture was then filtered to give the finished additive concentrate. Analysis: Barium 9.86%; sulfur 4.43%; phosphorus 2.06%.

EXAMPLE 13 A mixture-of 300 parts of p-tert.-octyl phenol :and 200 parts of a conventionally refined naphthenic oil of 50 seconds Saybolt viscosity at 210 F. was heated to C. Then parts of Ba(OH)2.8I-I2O were slowly added and the temperature gradually raised to about 150 C. and

heated until substantially all of the water-of react-ionhad been removed. The product obtained was quite viscous when hot and practically solid when cool.

200 parts of .this materialwere heated with 10 parts of P2S5'for three hours at -200 C. After removal of a small amount ofinsoluble matter, the resulting additive was found to contain 3.71 sulfur and 1.55% phosphorus.

EXAMPLE 14 The purpose of the following test was to determine the corrosion inhibiting effect of adding a small quantity of various products prepared as in .preceding examples to .a lubricating oil base.

.The same base oil was used in all cases, this being a well refined solvent extracted paraifinic type mineral lubricating oil of S. A. E. 20grade; Each oil blend contained 0.625% of additive concentrate of 40% strength-so that the amount of ;additive actually present in the final blend was The tests were conducted as follows: 500 cc. of

oil to be tested were placedrin a glass oxidation bearings of copper-lead alloy of known weight the sample during the test. Air'wasithen blown through the oil at the rate of 2 cu. ft. perhour. To increase the severity of the test, the bearings were washed and weighed atthe end of each four hour'period and then polishedand reweighed before'continuing for anotfi'zr four hour period.

1 l The results show the cumulative weight loss at the end of each four hour period. The corrosion life indicates the number of hours required for the bearings to lose 100 mgs. in weight, determined by interpolation or extrapolation of the data obtained. The results are shown in Table I.

was borne out by the results of the tests in actual engine operation.

Although in most instances the additives of the present invention will of themselves impart sufiicient improvement to lubricating oils to give very satisfactory results, still greater improve- Table I Cumulative bearing weight loss mg./25 sq. cm.

Oil blend Corrosion life, hrs.

4 8 12 16 20 24 28 32 36 40 hrs. hrs. hrs. hrs. hrs. hrs. hrs. hrs. hrs. hrs.

Base oil 5 181 6. Base oil+product of Example 1. 0 0 9 21 38 51 123 30. Base oil+product of Example 2. 0 2 8 18 29 42 56 77 97 36. Base oil+product of Example 3. 0 0 16 27 48 6b 88 106 35. Base oiH-product of Example 4. 0 0 2 6 13 32 40 52 64 50. Base oil-l-product of Example 5.... 0 0 5 ll 19 29 46 57 71 86 44. 1 Base oil+product of Example 6 0 0 0 12 24 46 3637 Base oil+product of Example 7..-. 0 0 0 12 36 58 80 116 30. Base o1l+product of Example 9 0 0 l 3 3 6 9 17 22 26 Not determined. Base oil+product of Example 10... 0 0 0 l 5 7 10 14 19 Not determined. Base oil+bariun1 alkyl phenate of Example 11 37 88 155 9.

1 By extrapolation.

1 Diflicult to extrapolate accurately as weight loss was only 25-26 mg. after 40 hours of test.

It will be observed that all of the products con- 25 taining phosphorus and sulfur were very effective in reducing the corrosiveness of the base oil toward the alloy bearings. By contrast, a metal phenate which had not been treated with a phosphorus sulfide was substantially ineffective in reducing the corrosiveness.

EXAMPLE 15 In the following tests, lubricating oil blends containing additives of the present invention were tested in a single cylinder Caterpillar Diesel engine run under high temperature, high load conditions, namely, 18.7 B. H. P. output, 850 R. P. M., 195 F. oil temperature and 140 F. atmospheric temperature for 60 hour periods. After each test was completed the engine parts were examined and given demerit ratings based on their condition. The individual ratings were weighted according to their relative importance and an overall rating calculated from them. It should be pointed out that the lower the demerit rating the better the engine condition and hence the better the oil performed in the engine. In these tests the base oil was a solvent extracted Mid-Continent parafiinic oil of 52 seconds viscosity Saybolt at 210 F. Results of these tests are shown in the following table.

Table II Engine demerits Cu Pb com necting Oil blend Piston rod bear- Over- Ring Skirt Rings ing wt.

all zone Varnish stuck loss, mg.

Base oil 1.46 1.55 1.00 1 82 Base oil+2.5% product of Example 1..-- 0.69 0.59 0 0 1 None Base oi1+2.5% prodnot of Example 2..-- 0.86 1.10 0.25 0 25 Base oil+2.5% productof Example 3-... 0.79 0.67 0 0 None Base oil+2.5% product of Example 5--.. 0.67 0.65 0 0 l4 1 Bearings gained slightly in weight.

It will be readily seen that the performance of the base oil in the engine was materially improved by incorporation of the agents of the present invention. It should likewise be noted that the, capacity of these additives to inhibit corrosiveness, as indicatedby laboratory, tests,

ment may often be obtained by employing these addition agents in conjunction with other additives of the detergent type such as metal soaps, metal phenates, metal alcoholates, metal phenol sulfides, metal o-rgano phosphates, thiophosphates, phosphites and thiophosphites, metal sulfonates, metal thiocarbamates, metal Xanthates, and thioxanthates, and the like.

Thus'the addition agents of our invention may be used in mineral lubricating oils in conjunction with one or more of the following representative materials:

Barium te1't.-octyl phenol sulfide Cobalt tert.-amyl phenol sulfide Calcium mahogany sulfonates Tin salt of wax alkylated phenol sulfide Strontium mahogany sulfonates Magnesium cetyl phenate Nickel oleate Calcium dlchlorostearate Aluminum-calcium mixed soap of fatty acids from oxidation of petroleum fractions Calcium isohexadecyl phenol sulfonate Barium octadecylate Calcium phenyl stearate Nickel dibutyl dithiocarbamate Nickel amyl xanthate Barium dioctyl dithiophosphate Zinc methyl cyclohexyl dithiophosphate Calcium dihexadecyl monothiophosphite Calcium cetyl phosphate Barium mahogany sulfonates Zine diisopropyl salicylate Tin naphthenate Aluminum naphthenate Magnesium mahogany sulfonates Calcium double salt of octadecyl phenol sulfonic acid Barium phenate-zinc sulfonate of isohexadecyl phenol sulfonic acid Barium di-tert.-amyl phenol sulfide Calcium phenate-barium cai-boxylate of octadecyl salicylic acid Particularly advantageous are lubricant comamples of such compositions include the following:

. Per cent organo metallic compounds, metallic or other 1. Additive concentrate of the present inven soaps, sludge dispersers, anti-oxidants, thickention 1.5 ers, viscosity index improvers', oiliness gents, res- Calcium mahogany sulfonates 0.6 ins, rubber, olefin polymers, voltolized fats, voltol- Mineral lubricating oil 97.9 5 ized mineral oils, and/or voltolized waxes and col- 2. Additive concentrate of the present invenloidal solids such as graphite or zinc oxide, etc.

tion 2.5 Solvents and assisting agents, such as esters, ke- Barium mahogany sulfonates 1.5 tones, alcohols, aldehydes, halogenated or ni- Mineral lubricating oil 96 trated compounds, and the like, may also be em- 3. Zinc mahogany sulfonates 3.0 ployed.

Additive concentrate of the present inven- Assisting agents which are particularly desirti 3.0 able are the higher alcohols having eight or more Mineral lubricating oil 94 carbon atoms and preferably 12 to carbon atoms. The alcohols may be saturated straight Thelubncatmg 011basestocksusedmthecom' l5 and branched chain aliphatic alcohols such positions of this invention may be straight mineral lubricating oils or distillates derived from paraffim'c, naphthenic, asphaltic or mixed base crudes, or if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constituents have been carefully removed. The oils may be refined by conventional methods using acid, alkali and/or clay or other agents such as aluminum chloride, or they may be extracted oils produced, for example, by solvent extraction with solvents of the type of phenol, sulfur dioxide, furfural, dichloro ethyl ether, propane, nitrobenzene, crotonaldehyde, etc. Hydrogenated oils or white oils may be employed as well as synthetic oils prepared, for example, by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products. In certain instances cracking coal tar fractions and coal tar or shale oil distillates may also be used. Also, for special applications, animal, vegetable or fish oils or their hydrogenated or voltolized products may be employed, either alone or in admixture with mineral oils.

For the best results the base stock chosen should normally be that oil which without the new additive present gives the optimum performance in the service contemplated. However, since one advantage of the additives is that their use also makes feasible the employment of less satisfactory mineral oils or other oils, no strict rule can be laid down for the choice of the base stock. Certain essentials must of course be observed. The oil must possess the viscosity and volatility characteristics known to be required for the service contemplated. The oil must be a satisfactory solvent for the additive, although in some cases auxiliary solvent agents may be used. The lubricating oils, however they may have been produced, may vary considerably in viscosity and other properties depending upon the particular use for which they are desired, but they usually range from about 40 to 150 seconds Saybolt viscosity at 210 F. For the lubrication of certain low and medium speed Diesel engines the general practice has often been to use a lubricating oil base stock prepared from naphthenic or aromatic crudes and having a Saybolt viscosity at 210 F. of 45 to 90 seconds and a viscosity index of 0 to 50. However, in certain types of Diesel service, particularly with high speed Diesel engines, and in aviation engine and other gasoline engine service, oils of higher viscosity index are often preferred, for example, up to 75 to 190, or even higher, viscosity index.

In addition to the materials to be added according to the present invention, other agents may also be used such as dyes, pour de ressors, heat thickened fatty oils, sulfurized fatty oils,

as octyl alcohol (CsHi'zOH) lauryl alcohol (C12H25OI-I) cetyl alcohol (C16H33OH) stearyl alcohol, sometimes referred to as octadecyl alcohol, (C1aH31OH),heptadecyl alcohol (C17H35OH), and the like; the corresponding olefinic alcohols such as oleyl alcohol; cyclic alcohols, such as naphthenic alcohols; and aryl substituted alkyl alcohols, for instance, phenyl octyl alcohol, or octadecyl benzyl alcohol or mixtures of these various alcohols, which may be pure or substantially pure synthetic alcohols. One may also use mixed naturally occurring alcohols such as those found in wool fat (which is known tocontain a substantial percentage of alcohols having about 16 to 18 carbon atoms) and in sperm oil (which contains a high percentage of cetyl alcohol) andalthough it is preferable to isolate the alcohols from those materials, for some purposes, the wool fat, sperm oil or other natural products rich in alcohols may be used per se. Products prepared synthetically by chemical processes may also be used such as alcohols prepared by the oxidation of petroleum hydrocarbons, e. g., paraffin wax, petrolatum, etc.

These assisting agents serve to enhance the detergent and sludge dispersive qualities and aid the solubility of the metal-containing additives and at the same time impart some oiliness properties to the lubricating oil compositions.

In addition to being employed in crankcase lubricants the additives of the present invention may also be used in extreme pressure lubricants, engine flushing oils, industrial oils, general machinery oils, process oils, rust preventive compositions, and greases. Also their use in motor fuels, Diesel fuels and kerosene is contemplated. A particular application in this regard is their use in motor fuels containing tetraethyl lead or other anti-knock agents, the additives of the present invention serving not only as anti-oxidants for the fuel but also as stabilizers for the anti-knock agent itself. Since these additives exhibit anti-oxidant properties and are believed also to possess ability to modify surface activity, they may be employed in asphalts, road oils, waxes, fatty oils of animal or vegetable origin, soaps and plastics. Similarly, they may be used in natural and synthetic rubber compounding both as vulcanization assistants and as anti-oxidants, and generally they may be used in any organic materials subject to deterioration by atmospheric oxygen,

The present invention is not to'be considered as limited by any of the examples described herein which are given by way of illustration only, but it is to be limited solely by the terms of the appended claims.

We claim:

l. A petroleum hydrocarbon material containing a small quantity, sufficient to stabilize said material of a reaction product of a sulfide of phosphorus with a compound of the formula where Ar is an aromatic nucleus, R is an alkyl radical having at least carbon atoms, X is a member of the group consisting of oxygen and sulfur, and M is a divalent metal of group II of the periodic table and selected from the group consisting of calcium, barium, strontium, magnesium and zinc.

2. A mineral lubricating oil containing a small quantity, sufiicient to stabilize said oil, of a reaction product of a sulfide of phosphorus with a compound of the formula where R is an alkyl radical having at least 5 carbon atoms, M is a divalent metal of group II of the periodic table and selected from the class consisting of calcium, barium, strontium, magnesium and zinc.

4. A lubricating oil according to claim 3 in which R of the formula is a, tertiary octyl radical.

5. A mineral lubricating oil containing a small quantity, s'ufficient to stabilize said oil, of a re action product of a sulfide of phosphorus with a product obtained by reacting barium hydroxide with a tertiary octyl phenol.

6. A mineral lubricating oil containing a small quantity, sufficient to stabilize said oil, of a reaction product of elemental sulfur and elemental 16 phosphorus with a product obtained by reacting barium hydroxide with a tertiary octyl phenol.

7. A mineral lubricating oil containing a small quantity, sufficient to stabilize said oil, of a product obtained by reacting about one molecular proportion of phosphorus pentasulfide in a mineral oil with about two molecular proportions of the barium salt of an alkylated phenol at to C., the alkyl group of the phenol having at least 5 carbon atoms.

8. A mineral lubricating oil according to claim 7 in which the additive is obtained by reacting the sulfide of phosphorus with the metal salt in the presence of a minor proportion of a higher fatty alcohol.

9. A mineral lubricating oil according to claim '7 in which the barium salt is the barium salt of ptert.-octyl phenol.

10. A mineral lubricating oil containing a product prepared according to claim '7 which product has been heated at a temperature of 150 to C. until itscopper staining tendency has been substantially reduced.

11. A mineral lubricating oil containing a small quantity, sufficient to stabilize said oil, of a reaction product of phosphorus tetritaheptasulfide (P481), with a barium diamyl phenate.

12. A mineral lubricating oil containing a small quantity, suflicient to stabilize said oil, of a reaction product of elemental sulfur and a sulfide of phosphorus with a metallic salt of an alkylated phenol, the metal of said salt being a divalent metal-of group II of-theperiodic table and selected from the class consisting of calcium, magnesium, barium, strontium, and zinc.

13. A mineral lubricating oil containing a small quantity, sufiicient to stabilize said oil, of a product formed by reacting barium p-tert.-octyl phenate first with elemental sulfur and then with phosphorus pentasulfide.

14. A mineral lubricating oil according to claim 2 in which the sulfide of phosphorus is phosphorus pentasulfidc.

15. A mineral lubricating oil according to claim 3 in which the sulfide of phosphorus is phosphorus pentasulfide.

JOHN G. McNAB. DILWORTI-I T. ROGERS.