US2367470A - Compounded oil - Google Patents

Description

Pat'ented Jan. 16, 1945 COMPOUND!!!) OIL George L. Neely and Frank W. Kavanagh, Berkeley, Calif assignors to Standard Oil Company of California, San Francisco, Calif., a corporatlon of Delaware No Drawing. Original application June 20, 19:9,

eerial No. 280,124. Divided and this application February it, 1943, Serial No. 476,056

no invention relates to compounded lubricatng oils, and especially involves the provision of mproved lubricating oils for internal combustion mes which will inhibit piston ring sticking and which will possess other advantageous properties not obtainable with prior known single comsounding agents. Additionally, the invention provides lubricants having not only the ability to inhibit piston ring sticking but characterized by reduced corrosivity toward bearing metals, rerinsed jell tendencies where jelling may not be desired, and enhanced lubrication values as indiby factors such as improved ability to prevent scoring and uneven or undue wear of pistons, piston rings or cylinder walls of engines, and also as determined by ability to wet or adhere to hot metal surfaces, by lower wear, by lower iriction and higher him strength, and by enhanced protectlon to bearings under high loads. The principles of this invention also permit production of compounded lubricants and compounding agents therefor having improved stability as respects redistance to oxidation, to high temperatures, to storage at low temperatures, and to storage in the presence of water.

This application is a division of our copending application Serial No. 280,124, filed June 20, 1939 now Patent l lo. 2,322,307.

The desirability of preventing the formation oi adhesive oxidation products in hydrocarbons at elevated temperatures such as 425 to 525 F. has been recited. in general, however, oxidation hihibitors which are operative at lower temperatures to inhibit the formation or such materials are not operative at extremely high temperatures, such as 500 F. Because of the inherent instahility of hydrocarbons in the presence of an oxidining agent under such extreme conditions of temperature, the possibility of finding a satisfactory oxidation inhibitor has not been promising,

there appears to be no own law oi chemical nature which would enable one to predict or select from the vast list of chemical compounds those which would be operative at temperatures above 425 F. A large number of known oxidation inhibitors have been tried under these severe conditions and round to be unsatisfactory or totally inoperative.

When hydrocarbon compounds such as those occurring in oral oils of the lubricating boilingrange are heated to temperatures of from approximately 425 to 525 F. in the presence of an oxidizing agent such as an oxygen-containing gas, these compounds are partially oxidized and tend to deposit an adhesive gum or resinous maall? terial on surfaces with which they are in contact. Analysis of such deposits indicates that the adhesive constituents comprise oxy or hydroxy organic acids and resinous complexes of these acids,

which complexes are of unknown constitution and are apparently produced by further oxidation of the acids and/or by condensation as through inter-esteriflcation of the hydroxy roups present therein.

Ithas been discovered that incorporation of certain metal salts of different organic acids in the hydrocarbon mixture will inhibit formation of an adhesive deposit on metal surfaces at elevated temperatures, although such salts may not prevent or inhibit partial oxidation and decomposition of the hydrocarbons. The formation of adhesive deposits is prevented by the metal salts altering the course of the oxy aid resinification reaction.

it is often found that salts in which the acid components consist entirely of one acid are not satisfactory compounding agents for lubricating oils, or at least do not possess ther properties which are desirable or necessary in liquid lubricating compositions. These deficiencies may arise from unsatisfactory wear rate, instability of either the compounding agent or the compounded oil, or both, at high temperatures, instability of the oil solution of the compounding agent in storage or in the presence of water, undue corrosivity of the compounded oil toward bearing metals such as cadmium-silver or copper-lead alloys, unsatisfactory solubility of the compounding agent in the oil at low temperatures as indicated by cloud formation or jelling, undue foaming, un-

satisfactory adhesion of the compounded oil to hot metal surfaces. and undesirably high friction or low film strength.

The present invention avoids at least part of the above diillculties by incorporating in the lubricating oil mixed organic salts of certain metals, said mixed salts containing diflerent types of organic acids.

In producing the lubricating compositions of this invention, salts of metals selected from the group consisting of aluminum, calcium, barium, strontium, zinc, magnesium, cobalt, cadmium, manganese, tin and chromium may be utilized. Suitable mixtures and/or complex salts may be prepared by precipitation from aqueous solution. Thus one method comprises preparing an aqueous solution containing alkali metal salts or the mixture of acids in question, e. g. sodium naphthenate and sodium stearate, in substantially equal quantities, and then precipitating the polyvalent metal salts of these acids by adding a solution containing the appropriate metal ion, e. g. an aqueous solution of aluminum sulfate. Such precipitation processes are preferably carried out in the presence of an organic solvent to take up the oil-soluble organic salt as it is formed. A suitable solvent comprises lubricating oil. It is to be understood that the invention, in its broader aspect, is not limited to salts prepared by simultaneous precipitation or by any other specific method.

To illustrate results which may be obtained by utilizing metal salts containing difierent types of organic acids, the following specific examples of lubrication problems involved and difilculties overcome are given:

Incorporation of both aluminum naphthenates and aluminum salts of long chain fatty acids in lubricating oils gives improvements in ubricants which are not obtainable with either salt alone. For example, 1% aluminum stearate, when dissolved in a mineral oil lubricant, causes the formation of a jell and tends to separate from the oil at low temperatures. Such a lubricant is unsatisfactory for use in internal combustion engines. By contrast, addition oi 0.5% aluminum naphthenate and 0.5% aluminum stearate (total aluminum salt content is still 1%) gives a liquid non-jelling lubricant, and the tendency of the aluminum stearate to precipitate out of the oil solution at low temperatures is avoided.

Furthermore, the lubricant containing aluminum naphthenate and aluminum stearate in combination not only possesses the ability to withstand severe high temperatures without depositing gum and carbon around-the piston rings of an internal combustion engine but also gives superior protection to the Babbitt bearings of such engines. The following. engine tests will illustrate this property of the oil.

Reduced area bearing tests Acidrefinedfi. A. E. Acid refined B. A. E. Ilwestcn oil+lg, 30 western oil+}i% iififit iiq' ii flmdfa ii" stearic acid uminumlteer te w Condition &3? Condition singlecylindercatsb 7 6 failed 4 1 cracked gglsr engine 18 (4 had] slightly.

ur test. (Bear- (Ilckedi lugs cut awa to increase unit above nor- It is to be noted that the above test is an extremely severe one and involves bearing loads not encountered in service. This test accentuates the ability of the lubricant to protect bearings under extreme conditions.

A second test illustrates performance of the same oil in protecting full size hearings in a i-cylinder RD-4 caterpillar Diesel engine operating under severe conditions of full load and speed. The conditions of the test were: load, 75 lbs. B. M. E. P.; speed, 1400 R. P. M.; jacket temperature, 75 F.; oil temperature, 185 F. In this test there was no failure of any bearings after 541 hrs. of operation, whereas with a lubricant containing 1% aluminum dinaphthenate and 0.25% stearic acid failure of a bearing occasionally occurs under the severe conditions of the test after 200 hrs. operation.

Tests in which a single cylinder gasoline engine was operated under severe conditions designed to accelerate piston ring sticking show that an oil containing aluminum naphthenate and aluminum stearate will inhibit piston ring sticking under such conditions for 120 hrs. or more of engine operation, whereas the same lubricating oil without the addition of the aluminum salts will permit piston ring sticking in 30 to 40 hrs.

The 011 containing both aluminum dinaphthenate and aluminum stearate gives improved rates of wear over that obtained by the use of aluminum dinaphthenate alone. A laboratory wear-testing machine comprising a inch steel ball pressed against a 1% inch steel cylinder with a force of 40 lbs. andhaving the cylinder dipping in the oil to be tested and rotated at 600 R.P. M. for 16 hrs. was used to compare relative wear rates. Assuming the rate of wear to be on this machine with an oil containing 1% aluminum dinaphthenate alone, an 011 containing aluminum stearate plus aluminum dinaphthenate gives only 30% as much wear as the oil containing only aluminum naphthenate. This represents a reduction of 70% obtained by the use of the combination of salts of aluminum.

For purposes of illustration and to enable preparation of a lubricating 011 according to the principles of this invention without unnecessary experimentation, the following example is given:

A basic aluminum naphthenate containing two equivalent weights of naphthenic acid to three equivalent weights of aluminum is obtained by any of the well known methods. Naphthenic acids are generally prepared by extracting the naturally occurring naphthenic acids from crude petroleum oils or other distillates containing them, usually by washing the said oils with dilute aqueous caustic soda solution whereby watersoluble alkali naphthenates are formed. The alkali naphthenate solution may then be extracted with organic solvents to remove the major proportion of inert mineral oil contained therein. The basic aluminum naphthenate may then be prepared by adding to a substantially neutral aqueous sodium naphthenate solution a caustic alkali and a water-soluble aluminum salt in proportions of one equivalent weight of hydroxide (OH) per three equivalent weights of aluminum. The water-insoluble basic aluminum naphthenate will be precipitated and the sodium salts will remain in solution. A mineral oil concentrate is prepared by dissolving ten parts by weight or the naphthenate in ninety parts by weight of the mineral oil. This concentrate is added to a mineral lubricating oil such as an S. A. E. 30 acid refined naphthenic lubricating oil stock, in quantities sufilcient to give 1% by weight or naphthenate based on the completed oil. This oil is then heated for aboutthirty minutes at a temperature of 250 I". by indirect heat. It superheated open steam is used for this heating operation a shorter time will generally sufiice.

An equal portion of oil base is compounded with aluminum stearate by dissolving the stearate in oil in quantities sufiicient to give a solution containing 1% aluminum stearate by weight. The oil containing the aluminum stearate is agitated thoroughly and heated to 350 F. until the salt is dissolved and the solution is clear. The batch may be heated in the presence of open steam until the viscosity at 210 F. is substantially equal to the viscosity of the original oil.

The two portions of oil, i. e. the one contaming 1% aluminum dinaphthenate and the other 1% aluminum stearate, are mixed in equal proportions at a temperature above 150 F. The aluminum stearate compounded portion preferably should not be allowed to cool after it has been prepared before mixing with the portion of oil compounded with the aluminum naphthenate.

The following further illustrates the advantages and effects which may be obtained by the use of complex or mixed salts prepared by precipitation from an aqueous solution containing water-soluble alkali salts of the corresponding acids. A mixed or-complex aluminum stearatenaphthenate may be prepared by dissolving sodium naphthenate and sodium stearate in equal proportions in water and adding aluminum sulzfate thereto until precipitation ceases. The following data are illustrative:

Stability Oil tested in storage Wear at 32 F.

S. A. E. 30 acid refined naphthenlc oil Stable... 0.36. B. A. E. 30 acid refined napbthenlc oil+1% aluminum dinaphthenate .do 1. 40. S. A. E. 30 acid refined naphthenic oil+l% aluminum stearate Separates Foam; and

son s. S. A. E. 30 acid refined naphthenlc 011+ 0.5% aluminum dinaphthenate Stable... 0.70, S. A. E. 30 cold refined naphthenic oil+ 0.5% aluminum steal-ate Separates Foam; and

son s. S. A. E. 30 acid refined naphthenic 011+ 0.5% aluminum dinaphthenate+0.5% aluminum steerate Btable. 0.40.

The procedure for determining the above data on wear is the same as previously described.

The above tests show that an oil containing aluminum stearate alone foams and sends in the wear test and that the compounding agent tends to separate at low temperatures. Likewise an oil containing aluminum dinaphthenate alone has a wear rate substantially higher than that of the corresponding uncompounded oil; When hath compounding agents, prepared either by simultaneous or separate precipitation, are added to the lubricating oil the aluminum naphthenate component prevents the foaming and scumng action obtained with aluminum stearate alone and maintains the stearate in solution at low temperatures. Also, the wear rate of the oil containing both aluminum dinaphthenate and aluminum stearate (total aluminum salt 1%) is 57% and 30% of the wear rate for the oils containing respectively 0.5% and 1% of aluminum dinaphthenate alone.

The relative proportions of naphthenate to stearate either in the complex or mixed salts may vary rather widely, depending upon the characteristic desired and the conditions to be encountered. In general, however, the proportion should range from four to six parts of the naphthenate to six to four parts of the stearate, respectively. Substantially equal parts of the stemate and naphthenate are preferred.

The invention is not limited to processes and compositions containing the above described specific complex or mixed salts but embraces liquid mineral oil compositions and processes of treating the same in which other mixed salts may be utilized. As has been previously stated, salts of the following metals are useful for the purposes of this invention: aluminum, calcium, barium.

strontium, zinc, magnesium, cobalt, cadmium. manganese, tin and chromium. The invention embraces, for eple, the following combinations or mixtures: saturated fatty acid-naphthenic acid salts, saturated fatty acid-phenate salts, saturated fatty acid-organo phosphoric acid salts, saturated fatty acid-aromatic carboxylic acid salts, naphthenic acid-sulfonic acid salts, naphthenic acid-phenate salts, naphthenic acid-organo phosphoric acid salts, naphthenic acid-aromatic carboxylic acid salts, suli'onic acid- Dhenate salts, sulfonic acid-organo phosphoric acid salts, sulfonic acid-aromatic carboxylic acid salts, phenate-organo phosphoric acid salts, henate-aromatic carboxylic acid salts.

Wherever used herein, the term "saturated fatty acids designates saturated acids of the fatty acid series containing more than approximately ten carbon atoms and includes substituted fatty acids, such as phenyl stearic acid. Likewise, the term organo phosphoric acid or organo substituted acids of phosphorus" is utilized to designate acids of phosphorus containing an organic substituent.

Examples oi. saturated fatty acid-naphthenic acid mixed or complex salts are: aluminum stearate-naphthenate, calcium stearate-naphthenate, zinc stearate-naphthenate, magnesium stearate naphthenate, cobalt stearate naphthenate, cadmium stearate-naphthenate, manganese stearate-naphthenate, tin stearate-naphthenate, and chromium stearate-naphthenate.

Examples of saturated iatty acid-sulfonic acid mixed or complex salts are: aluminum stearatecetyl anthracene sulfonate, calcium stearatecetyl anthracene sulfonate, zinc stearate-cetyl anthracene sulfonate, magnesium stearate-cetyl anthracene sulfonate, cobalt stearate-cetyl anthracene sulfonate, cadmium stearate-cetyl anthracene sulfonate, manganese stearate-cetyl anthracene sulionate, tin stearate-cetyl anthracene sulionate, and chromium s te-cetyl ant0 thracene sulionate.

Examples of saturated fatty acid-phenate mixed or complex salts are: aluminum stearatecetyl phenate, calcium stearate-cetyl phenate, zinc stearate-cetyl phenate, magnesium stearatecetyl phenate, cobalt stearate-cetyl phenate, cadrnium stearate-cetyl phenate, manganese stearate-cetyl phenate, tin stearate-cetyl phenate, and chromium stearate-cetyl phenate.

Examples of saturated fatty acid-organo phosphoric acid mixed or complex salts are: aluminum phenyl stearate-cetyi phosphate, calcium phenyi stearate-cetyl phosphate, zinc phenyl stearate-cetyl phosphate, magnesium phenyl stearate=cetyl phosphate, cobalt phenyl stearatecetyl phosphate, ium phenyl stearate-cetyi phosphate, manganese phenyl stearate-cetyl phosphate, tin phenyl stearate-cetyl phosphate. and chromium pheirvl stearate-cetyl phosphate.

Examples of saturated fatty acid-aromatic carboxylic acid mixed or complex salts are: aluminum stearate-cetyl benzoate, calciuni' stearatecetyl benzoate, zinc stearate-cetyl benzoate, magnesium stearate-cetyl benzoate, cobalt stearate= cetyl henzoate, cadmium stearate-cetyl benzoate. manganese stearate-cetyl benzoate, tin stearatecetyl benzoate, and chromium stearate-cetyl benzoate.

Examples of naphthenic acid-sulfonic acid mixed or complex salts are: aluminum naphthanate-cetyl anthracene sulfonate, calcium naphthenate-cetyl anthracene sulfonate, zinc naphthenate-cetyl anthracene sulfonate, magnesium naphthenate-cetyl anthracene sulfonate, cobalt naphthenate-cetyl anthracene sulionate, cadmium naphthenate-cetyl anthracene sulfonate,

manganese naphthenate-cetyl. anthracene sulfonate, tin naphthenate-cetyl anthracenesulfonate, and chromium naphthenate-cetyl anthracene sulfonate.

Examples of naphthenic acid-phenate mixed or complex salts are: aluminum naphthenate-cetyl phenate, calcium naphthenate-cetyl phenate, zinc naphthenate-cetyl phenate, magnesium naphthenate-cetyl phenate, cobalt naphthenatccetyl phenate, cadmium naphthenate-cetyl phenate, manganese naphthenate-cetyl phenate, tin naphthenate-cetyl phenate, and chromium naphthenate-cetyl phenate.

Examples of naphthenic acid-organo phosphoric acid mixed or complex salts are: aluminum naphthenate-cetyl phosphate. calcium naphthenate-cetyl phosphate, zinc naphthenatecetyl phosphate, magnesium naphthenate-cetyl phosphate, cobalt naphthenate-cetyl phosphate,

cadmium naphthenate-cetyl phosphate, manganese naphthenate-cetyl phosphate, tin naphthanate-cetyl phosphate, and chromium naphthehate-cetyl phosphate.

Examples of naphthenic acid-aromatic carboxylic acid mixed or complex salts are: aluminum naphthenate-cetyl benzoate, calcium naphthehate-cetyl benzoate, zinc naphthenate-cetyl benzoate, magnesium naphthenate-cetyl benzoate, cobalt naphthenate-cetyl benzoate, cadmium naphthenate-cetyl benzoate, manganese naphthenate-cetyl benzoate, tin naphthenate-cetyl benzoate, and chromium naphthenate-cetyl benzoate.

Examples of sulfonic acid-phenate mixed or complex salts are: aluminum cetyl phenatepetroleum sulfonate, calcium cetyl phenatepetroleum sulfonate, zinc cetyl phenate-petroleum sulfonate, magnesium cetyl phenate-petroleum sulfonate, cobalt cetyl phenate-petroleum sulfona-te, cadmium cetyl phenate-petroleum suli'onate, manganese cetyl phenate-petroleum sulfonate, tin cetyl phenate-petroleum sulfonate, chromium cetyl phenate-petroleum sulfonate, aluminum cetyl phenate-cetyl anthracene sulfonate, calcium cetyl phenate-cetyl anthracene sulfonate, zinc cetyl phenate-cetyl anthracene sulfonate. magnesium cetyl phenate-cetyl anthracene sulionate, cobalt cetyl phenate-cetyl anthracene sulfonate, cadmium cetyl phenate-cetyl anthracene sulfonate, manganese cetyl phenatecetyl anthracene sulfonate, tin cetyl phenatecetyl anthracene sulfonate, and chromium cetyl phenate-cetyl anthracene sulfonate.

Examples of sulfonic acid-organo phosphoric acid mixed or complex salts are: aluminum cetyl phosphate-petroleum sulfonate, calcium cetyl phosphate-petroleum sulfonate, zinc cetyl phosphate-petroleum sulfonate, magnesium cetyl phosphate-petroleum sulfonate, cobalt cetyl phosphate-petroleum sulfonate, cadmium cetyl phosphate-petroleum suli'onate, manganese cetyl phosphate-petroleum sulfonate, tin cetyl phosphate-petroleum sulfonate, chromium cetyl phosphate-petroleum sulfonate, aluminum cetyl phosphate-cetyl anthracene sulfonate, calcium cetyl phosphate-cetyl anthracene sulfonate, zinc cetyl phosphate-cetyl anthracene sulfonate, magnesium cetyl phosphate-cetyl anthracene sulfonate, cobalt cetyl phosphate-cetyl anthracene sulfonate, cadmium cetyl phosphate-cetyl anthracene sulionate, manganese cetyl phosphate-cetyl anthracene sulfonate, tin cetyl phosphate-cetyl anthracene sulfonate, and chromium cetyl phosphate-cetyl anthracene sulfonate.

Examples of sulfonic acid-aromatic carboxylic acid mixed or complex salts are: aluminum cetyl benzoate-petroleum sulfonate, calcium cetyl benzoate-petroleum sulfonate, zinc cetyl bensoatepetroleum sulfonate, magnesium cetyl bensoatepetroleum suifonate, cobalt cetyl benzoate-petroleum sulfonate, cadmium cetyl benzoate-petroleum sulfonate, manganese cetyl benzoate-petroleum sulfonate, tin cetyl benzoate-petroleum sulfonate, chromium cetyl benzoate-petroleum sulfonate, aluminum cetyl benzoate-cetyl anthracene sulfonate, calcium cetyl benzoate-cetyl anthracene sulfonate, zin cetyl benzoate-cetyl anthracene sulfonate, magnesium cetyl benzoatecetyl anthracene sulfonate, cobalt cetyl benzoatecetyl anthracene sulfonate, cadmium cetyl ben-V zoatacetyl anthracene sulfonate, manganese cetyl benzoate-cetyl anthracene sulfonate, tin cetyl benzoate-cetyl anthracene sulfonate, and chromium cetyl benzoaiz-cetyl anthracene sulfonate.

Examples of phenate-organo phosphoric acid mixed or complex salts are: aluminum cetyl phenate-cetyl phosphate, calcium cetyl phenate-cetyl phosphate, zinc cetyl phenate-cetyl phosphate, magnesium cetyl phenate-cetyl phosphate, cobalt cetyl phenate-cetyl phosphate, cadmium cetyl phenate-cetyl phosphate, manganese cetyl phenate-cetyl phosphate, tin cetyl phenate-cetyl phosphate, and chromium cetyl phenate-cetyl phosphate.

Examples of phenate-aromatic carboxylic acid mixed or complex salts are: aluminum cetyl phenate-cetyl benzoate, calcium cetyl phenatecetyl benzoate, zinc cetyl phenate-cetyl benzoatc, magnesium cetyl phenate-cetyl benzoate, cobalt cetyl phenate-cetyl benzoate, cadmium cetyl phenate-cetyl benzoate, manganese cetyl phenatecetyl benzoate, tin cetyl phenate-cetyl benzoate, and chromium cetyl phenate-cetyl benzoate.

The combinations herein disclosed yield lubricants having improved characteristics which are not obtainable with metal salts having single organic acid components. In general, the combinations of this invention cooperate to give lu- 'bricants having one or more improved characteristics as compared with lubricant using the single elements of the combinations. For example, mixed salts having a. fatty acid component give improved lubrication value or resistance to wear and enhanced protection of bearings operating under severe conditions. Combinations containing phenate components have lower corrosion and greater stability at elevated temperatures than do oils containing a fatty acid salt alone, for instance. Also, the phenate components increase the stability of the oil solution of the fatty acid salts and the like. The organo phosphoric acid component increases the stability of the oil to high temperatures and its resistance to oxidation, as well as improves wetting and adhesion characteristics of the oil to hot metallic surfaces. This component also reduces the corrosivity of the oils toward copperlead or cadmium-silver bearing metal alloys. Certain of the sulfonates reduce friction, corrosion, and enhance oxidation stability of particular combinations. The phenates and sulfonates tend to reduce Jen-formation of other components of the combinations in certain instances.

The phenates used in the combinations of this invention are preferably high molecular weight compounds in which the phenolic radical contains at least eleven carbon atoms. The organo phosphate compounds are also preferably high molecular weight materials in which the acid of phos phorus contains an organic substituent having at least twelve carbon atoms. It should be observed that the invention, in its broader aspects, is not limited to substituted phosphoric acids but includes other substituted acids of phosphorus, such as phosphorous acid, as well as other substituted acids of pentavalent phosphorus.

The proportion of metal salts added to the hydrocarbon mixtures may vary widely, depending upon the salt selected and the conditions to be encountered. The present invention is primarily concerned with the production of liquid hydrocarbon compositions and the proportion of the metal salts should therefore preferably be insufii= cient to solidify the hydrocarbon mixture. In general, it has been found that from approximately 0.5% to approximately 2% of total salt content, based on the weight of the hydrocarbons, serve the purposes of the invention although as little as 0.1% or as much as 5% is not precluded. The metal salts may be incorporated in high boiling hydrocarbons of widely different types. Hydr': .arbons of petroleum origin are the most commonly available and will be most generally utilized. Pennsylvania, Mid-Continent or California petroleums are suitable sources for high boiling hydrocarbons of the type here involved. Although parafllnic oils such as commonly obtained from Pennsylvania crudes are not precluded, it has been found that acid refined naphthenic base oils are more readily susceptible to improvement as respects formation of adhesive resinous deposits on metal surfaces at elevated temperature. Synthetic hydrocarbons, for ex-' ample, olefin hydrogenated polymers such as butene, isobutene or mixed butene hydrogenated polymers, may be utilized. In general, the hydrocarbon should be of a liquid consistency at ordinary atmospheric temperatures and should preferably have a boiling point above approximately 500 F. at atmospheric pressure.

The relative proportion of the respective acid components in the complex or mixed salts contained in the compounded lubricating oils herein disclosed will vary, depending upon the purposes to be served and conditions encountered durin use. In general, the ratio of acid components will be no greater than ten to one, and prefer-' ably will be from approximately four to one, on the one hand, to one to one, on the other handthese being stoichiometrical proportions.

The compositions of this invention have a number of applications and will be found to have utility where it is desirable to inhibit deposition and/o1- formation of adhesive gums on metal surfaces which are bathed in or are in contact with high boiling hydrocarbons subjected to elevated temperatures in the presence of an oxidizing agent such as an oxygen-containing gas. One example of such an application comprises the lubrication of Diesel engines in which the oil is spread in a thin film over the pistons, piston rings and cylinder walls of the engine, and is subjected to the oxidizing action of the compressed gases in the combustion chamber at temperatures of from approximately 425 to 525 F. or above which exist at the upper piston rings of such engines. In this particular application of the invention it should be noted that the hydrocarbons are subjected not only to high temperatures in thin films on the metal surfaces, but also to the high pressures necessary to produce spontaneous ignition of Diesel fuels. These pressures are approximately 400 to 600 lbs./sq. in. at the time of ignition of the fuel, and rise to pressures as high as 750 to 1150 lbsJsq. in. during combustion of the fuel. By the present process the normal course of reactions occurring in the oil under these conditions may be progressively altered so that formation and/or deposition of adhesive materials is prevented and piston ring sticking is inhibited.

The compositions of this invention are also applicable to the prevention of formation and/or deposition of adhesive materials from hydrocarbon mixtures in those various instances where an oil flows over a metal surface which is heated to high temperatures and where heat transfer is the primary object to be accomplished. For example, oil cooled electric resistances subject the oil to high temperatures at the oil-metal interface of the highly heated'electric resistance element. The deposition of adhesive gummy materials on the surface of the resistance element may be inhibited at temperatures as high as 425 to 525 F. and the efllciency of the heat transfer thereby maintained or increased. An oxidizing agent will generally be present in such heat transfer process by reason of dissolved oxygen which is contained in the oil being heated, as well as by reason of air which may be in contact with the oil at one or more points in the system.

The compounding agents herein disclosed may have one or more advantages depending upon the particular compounds selected, the proper"- tion utilized, and the environment which the compounded oil is to encounter. It should be observed, for example, that even though a compounded oil may be somewhat corrosive to copper-lead or cadmium-silver bearing metals, Babbitt bearings are little if at all affected by such corrosive action at temperatures where they are not unsatisfactory for other reasons, such as low melting point or lack of fatigue resistance. Hence, compounded oils which may not be particularly desirable for lubrication of copper-lead or cadmium-silver bearings may be highly useful and extremely advantageous in conjunction with the operation of internal combustion engines having bearings of Babbitt or other corrosion-resistant bearing metals. The present in-' vention, in its broader aspects, is therefore not limited to combinations having all or the greatest number of advantages, but embraces various of the less advantageous combinations which will find utility in particular applications where all the possible improvement in properties may" not be required or where the standard of performance may not be so high.

The mixed salts of this invention may be added to hydrocarbon oils containing other compounding ingredients, such as pour point depressors. blooming agents, compounds for enhancing the viscosity index of the hydrocarbon oil, etc. The invention in its broader aspects embraces hydrocarbon oils containing, in addition to the mixed salts herein disclosed, thickening agents in greaseforming proportions or in amounts insuflicient to form greases, as in the case of mineral castor machine oils or other compounded liquid lubricants.

A part of the subject matter disclosed in theoriginal specification of applicants earlier application Serial No. 62,814 on compounded lubrieating 011. now issued as Patent No. 2,163,622 of June 26, 1939, was divided out for inclusion in application Serial No. 280,124 and is also included in the present application.

While the character of this invention has been described in detail and numerous illustrations given, this has been done with the intention that no limitation should be imposed upon the invention thereby. It will be apparent to those skilled in the art that numerous modifications 1 a radical of a substituted acid of phosphorus containing an organic substituent.

2. A compounded liquid lubricant comprising a petroleum lubricating oil subject to deterioration and deposition of adhesive materials at elevated temperatures, said petroleum lubricating oil containing, in small amount suillcient substantially to reduce said deposition, oil-soluble mixed polyvalent metal salts having a petroleum sulionate radical and a radical of a substituted acid oi. phosphorus containing an oil-solubilizing hydrocarbon substituent.

3. A compounded liquid lubricant comprising a petroleum lubricating oil subject to deterioration and deposition of adhesive materials at elevated temperatures, said petroleum lubricating oil containing, in small amount suillcient substantially to reduce said deposition, oil-soluble mixed polyvalent metal salts having an alkaryl suli'onate radical and a radical of a substituted acid of phosphorus containing an oil-solubiliz'ing hydrocarbon substituent.

4. A compounded liquid lubricant comprising a petroleum lubricating oil subject to deterioration and deposition of adhesive materials at elevated temperatures, said petroleum lubricating oil containing, in small amount suillcient substantially to reduce said deposition, oil-soluble mixed polyvalent metal salts having a sulionate radical and a radical of a substituted oxyacld of phosphorus containing an oil-solubilizing hydrocarbon substituent.

5. A compounded liquid lubricant comprising a petroleum lubricating oil subject to deterioration and deposition of adhesive materials at temperatures above about 425 F., said petroleum lubricating oil containing about 0.5 to 5% by weight based on finished lubricant or oil-soluble mixed salts selected from the group consisting of magnesium, calcium, strontium, barium, zinc and cadmium salts, said mixed salts containing a radical of a hydrocarbon sulionic acid and a radical of a substituted acid of pentavalent phosphorus containing a hydrocarbon substituent, said radical oi sulionic acid and said radical of acid of phosphorus being present in the lubricant in stoichiometric proportions ranging irom about 4 parts 01! sulionic radical per 1 part of acid or phosphorus radical to about 1 part 0! sulionic radical per 4 parts of acid ct phosphorus radical.

8. A compounded liquid lubricant comprising a liquid hydrocarbon oil subject to deterioration and deposition of adhesive materials at elevated temperatures, said hydrocarbon oil containing, in an amount sufllcient substantially to reduce laid deposition, oil-soluble mixed polyvalent metal salts including a calcium salt and including a sulionate radical and a radical 01' an acid 01 phosphorus containing an organic substituent.

7. A compounded liquid lubricant comprising a liquid hydrocarbon oil subject to deterioration and deposition of adhesive materials at elevated temperatures, said hydrocarbon oil containing, in an amount suillcient substantially to reduce said deposition, oil-soluble mixed polyvalent metal salts including a zinc salt and including a sulionate radical and a radical of an acid of phosphorus containing an organic substituent.

8. A compounded liquid lubricant comprising a liquid hydrocarbon oil subject to deterioration and deposition of adhesive materials at elevated temperatures, said hydrocarbon oil containing, in an amount suillcient substantially to reduce said deposition, oil-soluble mixed polyvalent metal salts including a zinc salt of an acid of phosphorus containing an organic substituent and including a polyvalent metal sulionate.

9. A compounded liquid lubricant comprising a petroleum lubricating oil subject to deterioration and deposition oi. adhesive materials at elevated temperatures, said petroleum oil containing, in small amount sufilcient substantially to reduce said deposition, oil-soluble mixed polyvalent metal salts, including a calcium salt, or a petroleum sulfonic acid and of an acid of pentavalent phosphorus having an aliphatic substituent, the sulfonic radical and the acid of phosphorus radical of said salts being present in the lubricant in stoichiometric proportions ranging from about 4 parts of sulionic radical per 1 part 01' acid of phosphorus radical to about 1 part oi sulionic radical per 4 parts of acid of phosphorus radical.

10. A compounded liquid lubricant comprising a petroleum lubricating oil subject to deterioration and deposition of adhesive materials at elevated temperatures, said petroleum oil containing, in small amount sumcient substantially to reduce said deposition, oil-soluble mixed polyvalent metal salts, including a zinc salt, of a petroleum suli'onic acid and of an acid or pentavalent phosphorus having an aliphatic substituent, the sulionic radical and the acid of phosphorus radical of said salts being present in the lubricant in stoichiometric proportions ranging from about 4 parts oi suli'onic radical per 1 part 01' acid or phosphorus radical to about 1 part or suli'onic radical per 4 parts of acid of phosphorus radical.

GEORGE L. NEELY. FRANK W. KAVANAGH.