US3146201A - Lubricant composition - Google Patents

Description

3,146,201 LUBRICANT COMPOSITION Thomas A. Butler, Cleveland, Ohio, assignor to The Luhrizol Corporation, Wicirlifie, Ghio, a corporation of Ohio No Drawing. Filed July 22, 1960, Ser. No. 44,559 8 Claims. (Cl. 252-325) This invention relates to lubricant compositions and in a more particular sense to mineral oil compositions having improved resistance to deterioration under service conditions. The lubricant compositions are useful internal combustion engines, especially engines of the diesel type.

The problem of deterioration of lubricating oil and formation of harmful deposits under service conditions has been the cause of much concern in providing satisfactory lubrication of internal combustion engines. The problem is especially acute in lubricating engines of the diesel type Where the lubricant encounters temperatures above 700 F. and pressures above 1200 pounds per square inch. In recent years, it has been common practice to incorporate into a lubricating oil detergent additives which are capable of preventing the deposition of the products of oil degradation. Such additives include the metal salts of sulfonic acids, carboxylic acids and organic phosphorus acids. The basic metal salts, i.e., those in which the metal is present in stoichiometrically greater amounts than the organic acid radical, are especially elfective for this purpose. Unfortunately, however, these metal detergents tend to promote oxidation of the oil. Thus, while lubricant compositions containing such additives are improved with respect to their detergent properties, they are usually also characterized by a marked susceptibility to oxidative degradation.

Accordingly, it is an object of this invention to provide a means for reducing the oxidation tendencies of lubricant compositions having incorporated therein metalcontaining detergent additives.

It is also an object of this invention to provide lubricant compositions adapted for use in internal combustion engines.

It is further an object of this invention to provide lubricant compositions adapted especially for use in diesel engines.

These and other objects are achieved in accordance with this invention by a lubricating composition comprising a major proportion of a mineral lubricating oil, from about 0.1% to about 20% of an alkaline earth metal salt of an acidic composition selected from the class consisting of sulfonic acids and phosphorus acids derived from the reaction of a substantially aliphatic hydrocarbon with an inorganic phosphorus reagent, and a small amount, sufficient to increase the resistance to deterioration of said lubricating composition due to the presence therein of said alkaline earth metal salt, of anthranilic acid.

The amount of the detergent additive to be used in a lubricant composition of this invention will depend primarily upon the degree of detergency desired in the lubricant composition and the type of service to which the lubricant composition is to be subjected. For example, a lubricant for use in a gasoline engine of a passenger automobile may contain from 0.5% to 5% by weight of a detergent additive, whereas a lubricant for use in a diesel engine may contain as much as or more of a detergent additive. In other applications such as in two-cycle outboard motor type engines, a lubricant may contain only 0.1% or even less of a detergent additive.

The anthranilic acid is used in the lubricant compositions of this invention to reduce the oxidation-promoting tendencies of the metal detergent additive. Hence, the amount of anthranilic acid to be used depends to a large extent upon the amount and the type of the detergent additive used. A small amount of a detergent additive will usually require a correspondingly small amount of anthranilic acid. In most instances, from 0.01% to 0.5%, more often in the neighborhood of 0.02%0.2%, by weight of anthranilic acid in a final lubricant will suffice to counteract the oxidation tendencies of a lubarium are preferred for reasons of the particular eifectiveness of their salts as detergent additives in the lubricant compositions of this invention.

The sulfonic acids from which the detergent additives of this invention are derived may be either petroleum sulfonic acids (e.g., mahogany acids) or alkylaryl sulfonic acids prepared by the treatment of alkylated aromatic compounds with a sulfonating agent such as sulfur trioxide, chlorosulfonic acid, sulfuric acid or the like.

The organic radical of the sulfonic acid should contain at least about 12 aliphatic carbon atoms in order to impart oil-solubility.

The organic phosphorus acids from which the detergent additives are derived are principally those prepared by the treatment of a polymer of a lower mono-olefin such as ethylene, propene, isobutene or l-butene with a phosphorizing agent such as phosphorus pentasulfide, phosphorus heptasulfide, phosphorus sesquisulfide, phosphorus trichloride, phosphorus trichloride and sulfur, elemental phosphorus and a sulfur chloride, phosphorothioic chloride, etc. They may be prepared by chlorinating an olefin polymer and treating the chlorinated polymer with a phosphorizing agent. The phosphorized polymer may be hydrolyzed first before conversion to the metal salts. Interpolymers of the above-illustrated lower mono-olefins, aromatic olefins or diolefins likewise are useful for preparing the organic phosphorus acids provided that at least about 95% by weight of the interpolymer is composed of the lower mono-olefin units. Examples of the olefin polymers include polyisobutenes, polypropenes, polyethylenes, copolymer of of isobutene and 10% of styrene, copolymer of 98% of isobutene and 2% of chloroprene, copolymer of 99% of propene and 1% of piperylene, terpolymer of 98% of isobutene, 1% of butadiene and 1% of n-hexene, etc. Polymers of isobutene are most frequently used because of their ready availability. The molecular weights of the polymers may vary within wide ranges such as, for example, from 200 to 100,000 or even higher. Polymers of intermediate molecular weights, i.e., 50010,000 are especially useful.

As noted above the phosphorus acids are prepared from a substantially aliphatic hydrocarbon, i.e., one which may contain only incidental proportions of aromaticity and only such substituents as do not materially alfect the aliphatic character of the molecule.

The alkaline earth metal salts of sulfonic acids and organic phosphorus acids may be neutral or basic salts obtained by treatment of the acid with at least a stoichiometric amount of an alkaline earth metal neutralizing Patented Aug. 25, 1964 agent such as the metal oxide, metal hydroxide, metal carbonate, metal alcoholate, metal phenate, etc. The term basic metal salts is used to designate the metal salts of organic acids wherein the metal is present in a larger amount than is stoichiometrically equivalent to the organic acid radical. Examples of such metal salts include those prepared by the processes described in US Patents 2,616,905, 2,723,234, 2,921,901, 2,902,105, 2,906,709, 2,902,448, 2,865,956, 2,861,272, 2,316,080, and 2,316,081.

The most commonly employed methods for preparing the basic metal salts involve heating a mixture of an acid with a stoichiometric excess of an alkaline earth metal neutralizing agent at a temperature above about 50 C. and filtering the reaction mass in a diluent such as mineral oil to obtain a fluid product. The use of a fpromoter in the neutralization step to aid the incorporation of a large excess amount of metal is likewise known. Examples of such promoter compounds include phenolic substances such as phenol, naphthol, alkyl phenol, thiophenol, sulfurized phenol and condensation products of formaldehyde and a phenol; alcohols such as methanol, 2-propanol, octyl alcohol, Cellosolve, carbitol, ethylene glycol, stearyl alcohol, cyclohexy alcohol; amines such as aniline, phenylenediamine, phenothiazine, phenyl-{3- naphthylamine, dodecyl amine, etc. A particularly efiicient method comprises mixing an acid with an excess of a neutralizing agent, a promoter compound and a small amount of water, and carbonating the mixture at an elevated temperature, e.g., 60-150 C.

The present invention also contemplates the use of a corrosion inhibitor in conjunction with anthranilic acid and the detergent additive in a lubricant composition. Corrosion inhibitors particularly efiective for use in the lubricant compositions of this invention include the oil soluble alkaline earth metal salts of alkylated phenolic compounds such as, e.g., alkyl phenols, alkyl naphthols, sulfurized alkyl phenols or naphthols and condensation products of such phenolic compound with aldehydes or ketones. The alkyl radical in the phenolic compound should contain at least 7 carbon atoms in order to impart oil-solubility. Specific examples of such corrosion inhibitors include: barium salt of cetyl phenol, calcium salt of otcyl phenol, strontium salt of heptyl phenol, barium salt of bis-(hydroxyphenyl) sulfide, calcium salt of the condensation product of heptyl phenol with 0.5 mole of formaldehyde, calcium salt of his (hydroxylphenyl) di-sulfide, etc. Likewise useful are the basic alkaline earth metal salts of the alkylated phenolic compounds wherein the metal is present in stoichiometrically larger amounts than the phenolic radical. The basic salts may be prepared by heating a mixture of a phenolic compound with an excess of an alkaline earth metal neutralization agent, or treating such mixture with carbon an elevated temperature, e.g., 60l50 C.

Another class of corrosion inhibitors contemplated for use in the lubricant compositions of this invention are the metal salts of organic phosphorodithioic acids, especially the zinc and barium salts of dialkyl phosphorodithioic and dialkaryl phosphorodithioic acids. Such acids are preferably those in which the total number of the carbon atoms in the two alkyl radicals is at least about 7.6 per each phosphorus atom. The metal salts of such acids may be illustrated by e.g., zinc dipentyl phosphorodithioate, zinc dicyclohexyl phosphorodithioate, barium di(pheptylphenyl) phosphorodithioate, barium salt of propyl hexylphosphorodithioic acid, zinc salt of heptyl cresyl phosphorodithioic acid, etc.

Still another class of corrosion inhibitors includes the sulfurized or phosphosulfurized hydrocarbons or fatty materials such as the reaction products of a-pinene with sulfur or phosphorus pentasulfide, the reaction products of methyl oleate with phosphorus sesquisulfide, the reaction products of sperm oil with sulfur, dibutyl tetrasulfide, dipentyl trisulfide, etc.

Other corrosion inhibitors are the metal salts of organic thiocarbamic acids such as zinc diheptylphenyl dithiocarbamate, zinc dipentyl dithiocarbamate, cadmium cyclohexyl thiocarbamate, etc.

Yet another class of corrosion inhibitors consists of organic phosphites, especially diaryland dialkyl phosphites having the formula, (RO) P(O)H, wherein R is an aryl or an alkyl radical containing 4-30 carbon atoms. They may be prepared by the reaction of an alcohol or phenol or a mixture of alcohols or phenols with phosphorus trichloride. Examples of such phosphites include: dicyclohexyl phosphite, di(4-methyl-2-pentyl) phosphite, propyl octyl phosphite, methylcyclohexylpentyl phosphite, diphenyl phosphite, etc. Other phosphites such as triphenyl phosphite, tributyl phosphite, and hexyl dicresyl phosphite are likewise contemplated.

While any of the afore-mentioned corrosion inhibitors may be used, the particular combination of an alkaline earth metal salt of an alkylated phenolic compound with anthranilic acid and a metal detergent has been found to produce lubricants which show unexpectedly high resistance to oxidative degradation. Accordingly, such combination is preferred for use in preparing lubricants of this invention.

The amount of the corrosion inhibitor to be used in the lubricant compositions of this invention may be varied within the range of from about 0.1% to about 5% by weight, more often within the range of from about 1% to about 3% by weight.

The use in the lubricant compositions of this invention of other types of additives such as anti-foam agents, rust-inhibitors, pour point and viscosity index improving agents, etc. is likewise contemplated.

The following examples illustrate more specifically the additives useful in the lubricant compositions of this invention. All parts are by weight.

EXAMPLE A Neutral Calcium Detergent Additive A mineral oil solution containing 50% by weight of a sodium petroleum sulfonate (molecular weight 500) is heated at C. for 2 hours with a 20% stoichiometrically excessive amount of calcium chloride and 10% by weight of water. The mixture is then dehydrated by heating to 150 C. and the inorganic chlorides removed by filtration. The filtrate is an oil solution of a neutral calcium petroleum sulfonate.

EXAMPLE B Basic Calcium Detergent Additive A mixture of 520 parts of a mineral oil, 480 parts of a sodium petroleum sulfonate (molecular weight of 480) and 84 parts of water is heated at C. for 4 hours. The mixture is then heated with 88 parts of a 76% aqueous solution of calcium chloride and 72 parts of lime (90% purity) at 100 C. for 2 hours, dehydrated by heating to a water content of less than 0.5%, cooled to 50 C., mixed with parts of methyl alcohol and blown with carbon dioxide at 50 C. until substantially neutral. The mixture is then heated to C. to distill otf methyl alcohol and water and the resulting oil solution of the basic calcium sulfonate filtered. The filtrate is found to have a sulfate ash of 16%.

EXAMPLE C Basic Calcium Detergent Additive A mixture of 300 grams of mineral oil, 690 grams (0.5 mole) of neutral calcium mahogany sulfonate, 75 grams of water and 29 grams of lime (90% purity) is heated at 100 C. for 2 hours and then to 150 C. during a period of 7 hours. The mixture is blown with carbon dioxide at 150 C. until substantially neutral and filtered. The filtrate is found to have a sulfate ash content of 8.2%.

EXAMPLE D Basic Calcium Detergent Additive A mixture of 500 parts of a mineral oil, 500 parts of a neutral sodium petroleum sulfonate (molecular weight of 500), 67 parts of calcium chloride and 76 parts of water is heated at 100 C. for 4 hours and then mixed with 25.5 parts of lime (90% purity) at 100 C. for 2 hours. The mixture is then dried to 150 C. over a period of 7.5 hours and filtered. The filtrate is found to have a sulfate ash content of EXAMPLE E Basic Barium Detergent Additive A mixture of 490 parts of a mineral oil, 110 parts of water, 61 parts of heptylphenol, 340 parts of neutral barium, mahogany sulfonate and 227 parts of barium oxide is heated at 100 C. for 0.5 hour and then to 150 C. Carbon dioxide is then bubbled into the mixture until the mixture is substantially neutral. The mixture is filtered and the filtrate found to have a sulfate ash content of 25%.

EXAMPLE F Basic Barium Detergent Additive To 900 parts of a chlorinated polyisobutene having a chlorine content of 4.3% and a molecular Weight of 1000 there is added 150 parts of phosphorus trichloride at 110190 C. during a period of hours. The mixture is heated at 200 C. for 2 hours, at 180190 C./ 660 mm. for 1.5 hours, and then blown with nitrogen at 170 C. for 2 hours. The residue is hydrolyzed with steam to form an acidic intermediate. A basic barium salt is prepared by adding 400 parts of the acidic intermediate to a mixture of 495 parts of a mineral oil, 100 parts of heptylphenol, 38 parts of Water and 62 parts of barium oxide at 9095 C. during 1.5 hours. The mixture is heated at this temperature for 0.5 hour, mixed with 257 parts of barium oxide and carbonated at 130- 140 C. until it is substantially neutral. The resulting mixture is diluted with 280 parts of mineral oil and filtered. The filtrate is found to have a sulfate ash content of 25%. 1

EXAMPLE G Neutral Barium Detergent Additive A polypropene having a molecular weight of 2000 is mixed'with 10% by weight of phosphorus pentasulfide at 190 C. for 6 hours. The resulting phosphosulfurized polypropene is hydrolyzed by treatment with steam at 160 C. to produce an acidic intermediate which is then converted to the neutral barium salt by treatment with a stoichiometric amount of barium hydroxide.

EXAMPLE H Basic Magnesium Detergent Additive A methyl alcohol suspension containing 14% by weight of suspended magnesium methoxide is blown with carbon dioxide at 40 C. until it is acidic to a-naphtholbenzein indicator, whereupon a homogeneous solution is obtained. The solution (200 parts by weight) is added dropwise to 27 parts of an alkylated benzenesulfonic acid having a molecular weight of 450, 123 parts of a mineral oil and 75 parts of water, and the resulting mixture is heated to 150 C. The residue is filtered and the filtrate contains 40% by weight of sulfate ash.

EXAMPLE I Neutral Strontium Detergent Additive A copolymer of isobutene and styrene (molar ratio of 10.5 :1 respectively) having a molecular weight of 1000 is heated with 8.6% by weight of sulfur to 200 C. whereupon 37% by weight of phosphorus trichloride is added to the mixture at 170-200 C. during a period of 6 5 hours. The mixture is then subjected to distillation at 170 C./50 mm. for 1 hour, and the residue diluted with 44% by weight of a mineral oil. The oil solution is found to contain 3% of phosphorus, 4.7% of sulfur, and 2.7% of chlorine. Steam is passed into the oil solution to produce an acidic intermediate which is then treated with a stoichiometric amount of strontium hydroxide to produce a neutral strontium salt of an organic phosphorus acid.

EXAMPLE I Neutral Barium Detergent Additive To 4400 grams of a mineral oil solution containing 4.25 moles of sodium mahogany sulfonate there is added 680 grams of barium chloride dihydrate in 1500 ml. of water at 95 C. The mixture is heated at 90 C. for 1.5 hours, and the aqueous layer removed. The oil layer is washed with water-isopropanol-phosphoric acid mixture, then dried at 160 C./30 mm. and filtered. The filtrate has a sulfate ash content of 10.7%.

EXAMPLE K Basic Strontium Detergent Additive A mixture of 910 grams of a mineral oil solution containing 0.9 equivalent of strontium mahogany sulfonate,

80 grams of strontium hydroxide octahydrate and 145- grams of water is heated at 93-99 C. for 2 hours, then heated to 150 C. in 7 hours, and filtered. The filtrate has a sulfate ash content of 14.2%.

EXAMPLE L Basic Barium Detergent Additive A mixture of 900 grams of a mineral solution containing 0.41 mole of barium mahogany sulfonate, 46 grams of barium oxide, 145 grams of water and 64 grams of mineral oil is heated at 93 99 C. for 2 hours, then heated to 150 C. in 7 hours, and filtered. The filtrate has a sulfate content of 15:6

EXAMPLE M Neutral Calcium Detergent Additive To 6500 grams of a mineral oil solution containing 6.53 moles of sodium mahogany sulfonate there is added at 95% C. 622 grams of calcium chloride dihydrate in 1800 ml. of water. The mixture is heated at 95-100 C. for 0.5 hour and allowed to settle at room temperature for 2 days. The aqueous layer is removed, and the oil layer is Washed with water and then with a Water-isopropanolphosphoric acid mixture. The washed layer is dried and filtered. The filtrate has a sulfate ash of 6.9%.

EXAMPLE N Basic Barium Detergent Additive To a mixture of 1000 parts of a chlorinated polyisobutene having a chlorine content of 4.3% and a molecular weight of 1000 and parts of phosphorus trichloride, there is added portionwise throughout a period of .5 hour 61 parts of heptylphenol at 210 F. The mixture is heated to 390 F. whereupon an additional 1'10 parts of phosphorus trichloride is added throughout a period of 6 hours. The mixture is heated at 390 F. for 0.5 hour, blown with nitrogen at 360390 F./ 100 mm. for 2 hours, and then with steam at 300-320 F. for 3 hours. To a mixture of 270 parts of mineral oil, 18 parts of water and 15 parts of barium oxide, there are added 143 parts of the above steam-hydrolyzed product and 38 parts of heptylphenol at 190 -195 F., and then 125 parts of barium oxide at 200230 F. The mixture is heated to 270-280 F. and blown with carbon dioxide until substantially neutral. The mixture is heated to 270- 280 F and blown with carbon dioxide until substantially neutral. The residue is diluted with parts of mineral oil, blown with nitrogen at 310 F. for 0.5 hour, and filtered. The filtrate has a sulfate ash content of 25 7 EXAMPLE Basic Barium Detergent A dd i ti ve To a mixture of 6,245 grams (12.5 equivalents) of barium petroleum sulfonate, 1,460 grams (7.5 equivalents) of heptyl phenol and 2,100 grams of water in 8,045 grams of mineral oil there is added at 180 F. 7,400 grams (96.5 equivalents) of barium oxide. The addition of barium oxide causes the temperature to rise to 290 F. and this temperature is maintained until all of the water has been distilled away. The mixture then is blown with carbon dioxide until it is substantially neutral. 5,695 grams of mineral oil is added and the mixture filtered through a siliceous filter aid. The filtrate is diluted further with mineral oil to a barium content of 38.5% as sulfate ash.

EXAMPLE P Basic Calcium Detergent Additive Same as additive B except that sodium polydodecylbenzene sulfonate is used in the place of sodium mahogany sulfonate.

EXAMPLE Q Calcium Phenolic Corrosion Inhibitor A mineral oil solution containing 50% of cetyl phenol is heated with a stoichiometric amount of calcium oxide and 10% by weight of water at 150-170 C. for 8 hours. The mixture is then dried at 150 C./l mm. pressure.

EXAMPLE R Calcium Phenolic Corrosion Inhibitor A mixture of 315 parts of mineral oil, 125 parts of heptylphenol and 26.4 parts of lime is heated at 105 108 F. for minutes and to this mixture there is then added 5.8 parts of aqueous ammonium hydroxide and 29.3 parts of paraformaldehyde at 115-120 F. The mixture is maintained at 155-180 F. for 1 hour and then heated to 300 F. in 5 hours whereupon the water is removed by distillation. The residue is dried by heating at 300305 F. for 1 hour, mixed with 18 parts of a filter aid and filtered. The filtrate has a sulfate ash content of 6.2.

EXAMPLE S Calcium Phenolic Corrosion Inhibitor A mineral oil solution containing 50% by weight of a mixture of stoichiometrically equivalent amounts of his (heptylphenyl) sulfide and hydrated lime is heated at 200 C. for 6 hours and filtered. The filtrate is the neutral calcium salt.

EXAMPLE T Barium Phenolic Corrosion Inhibitor A mixture of 400 grams of heptylphenol, 54 grams of water, 1150 grams of mineral oil and 163 grams of barium oxide is heated at 160l70 C. for 2 hours and filtered. The filtrate has a barium content of 4.8%.

EXAMPLE U Magnesium Phenolic Corrosion Inhibitor A mineral oil solution containing 40% by weight of dipentylphenol is mixed with a 20% stoichiometric excess of magnesium methoxide suspended in methyl alcohol. The mixture is heated at reflux temperature for hours and then distilled to remove any volatile components. The residue is filtered to yield as the filtrate an oil solution of the magnesium salt.

EXAMPLE V Barium Phenolic Corrosion Inhibitor A mixture of 309 grams (1.5 equivalents) of octylphenol, 1500 grams of mineral oil, 344 grams (4.5 equivalents) of barium oxide and 180 grams (10 equivalents) of water is stirred at reflux temperature for an hour, then heated to 150 C. and held at 150-160 C. for an hour. Carbon dioxide is bubbled into the mixture for 35 minutes at 150 C. and the hot mixture is filtered. The filtrate has the following analysis: percent sulfate ash, 21.2; neutralization No. 16.7 (basic).

EXAMPLE W Zinc Phosphorodithioate Corrosion Inhibitor A phosphorodithioic acid prepared by the reaction of phosphorus pentasulfide with four moles of an equimolar mixture of sec-butyl alcohol and cyclohexyl alcohol is neutralized by treatment with a 20% stoichiometric excess of zinc oxide at C. The resulting zinc phosphorodithioate is filtered.

EXAMPLE X Phosphosulfurized Cyclic Hydrocarbon Corrosion Inhibitor A solution of 250 grams of pinene in 250 grams of mineral oil is heated with grams of phosphorus pentasulfide at 150 C. for 2 hours. The mixture is filtered and the filtrate has a phosphorus content of 4.8% and a sulfur content of 13%.

The following examples illustrate the lubricant composition of this invention.

Lubricant 1: Parts SAE 20 mineral oil 100 Anthranilic acid 0.02 Calcium detergent additive of Example A 6 Lubricant II:

SAE low-30 mineral oil 100 Anthranilic acid 0.05 Basic calcium detergent additive of Example D 10 Lubricant III:

SAE 30 mineral oil 100 Anthranilic acid 0.3 Basic barium detergent additive of Example E- 15 Calcium phenolic corrosion inhibitor of Example Q 3 Lubricant IV:

SAE 40 mineral oil 100 Anthranilic acid 0.075 Neutral barium detergent additive of Example G 3 Phosphosulfurized cyclic hydrocarbon corrosion inhibitor of Example X 2 Lubricant V:

SAE mineral oil 100 Anthranilic acid 0.1 Basic calcium detergent additive of Example D 10 Calcium phenolic corrosion inhibitor of Example R 2 Polyalkylsiloxane anti-foam agent 0.003 Polyalkylmethacrylate viscosity index improving agent 1.5 Alkenylsuccinic acid rust-inhibitor 0.05

Lubricant VI:

SAE 30 mineral oil 100 Anthranilic acid 0.01

Basic magnesium detergent additive of Example H 1 Calcium phenolic corrosion inhibitor of Example S 0.5 Lubricant VII:

SAE 30 mineral oil 100 Anthranilic acid 0.05 Neutral strontium detergent additive of Exarnple I 3 Zinc phosphorodithioate corrosion inhibitor of Example W 1 9 10 Lubricant VIII: Parts as well as many other within the broad definition of the SAE 30 Mineral oil 100 combination of the invention. Anthranilic acid The oxidation resistance of the lubricants of this in- Bas c barium de e g addltlve of Example 6 vention is shown by the results of the Air Oxidation Test Basiccalcmm det g Q l P 7 summarized in Table I. The test consists of bubbling Phenohc corroslon mhlbltor of Exam 2 5 air at the rate of 1 cubic foot per hour into 300 grams "ttjf 0 6 of a lubricant having immersed therein a sheet of copya (y 51 Oxane an 0am agen per (2 x 8 x 0.33 inches) as an oxidation promoter at Lubricant IX: I 100 300i5 F., and measuring the viscosity increase of the i gf q id 0 O3 10 l ricant at 24 hour intervals until a sharp increase in E i 5 33 g &;-- viscosity occurs. The results are expressed in terms of 1e ge a 1 e 4 percent of viscosity increase. It will be readily. appreci- Bagium g g g g gg ated that a smaller increase in viscosity indicates a greater ple V 1 r resistance to oxidative degradation of the lubricant. The LubricantX lubricant used in the tests consists of an SAE 30 grade SAE 3 mineral oil 100 oil to which has been added the corrosion inhibitor of EX- Anfhranih-c acid 01 ample R in various amounts according to the following Basic barium detergent additive of Example EL 4 scheduie: i i A cpmammg Welght Of.the Basic calcium detergent additive of EXam corrosion mhibnor; lubricant B containing 2% by weight ple B 6 of the corrosion inhibitor; and lubricant C containing 3% Polyalkyl acrylate viscosity index improving y Welght Of the b tor.

agent 2 It has been found also that lubricant compositions Polyalkyl acrylate anti-foam agent 0 .005 taining a mixture of barium and calcium detergent addi- Calcium phenolic corrosion inhibitor of Examtives in weight proportions within the range of from about P S 3 5:1 to about 1:5 respectively are especially susceptible to Lubricant XI: the oxidation-retarding effects of anthranilic acid. Ordi- SAE 'f 011 narily lubricant compositions contain from about 0.1% g h g t 3: to about 10% of each of the calcium and barium deter-' 232 gfig g g g gg i gf gent additives. These calcium and barium detergent adple B g 3 ditives, when used in combination in the same lubricant, polybutene vigcosity improving agent 5 most usually are sulfonates, i.e., a combination of calp l lk l il a ti f agent (10 03 clum sulfonate and a bar1um sulfonate. This particular Calcium phenolic corrosion inhibitor of Examcombination is especially eifective in the presence of ple R anthranilic acid.

TABLE I.AIR OXIDATION TEST RESULTS Anthra- Percent viscosity increase at end of test nilic Detergent additive period of Test Lubriacid 1% (1% addition by sample cent addition weight) by 72 144 166 weight) hours hours hours hours hours 1 A None 12%ofadditiveof 83 175 410 1V.V. Example 0. r 2 A 0.05 do 0 0 2 4 s 3 B None 9.4% of additive 80 V.V

of Example J 4 B 0.05 .do 0 0 41 107 133 5 B None 7% of additive of 21 183 314 796 Example K. e B 0.05 do 5 5 6 7 24 7 B None 6.4% of additive 31 346 V.V

of Example L. s B 0.05 ..-.do 3 3 61 159 9 0 None 10.4% of additive 16 692 V.V

of Example B. 10 0 0.05 do 10 14 47 227 604 11 0 0.1. do 10 12 17 83 292 12 B None 14.5% additive of 18 V.V

- Example M. 13 B 0.05 do 0 0 0 10 99 14 D 0.075 11%0fadditive of 10 17 35 79 Example P.

1 V.V., very viscous, i.e., viscosity increase above 450%500%. 2 SAE oil containing 0.1% of Zinc dioctyl phosphorodithioic acid as corrosion inhibitor Lubricant XII. P arts Examples of such lubricant compositions include min- SAE 30 mineral oil The above lubricants are of course merely illustrative and the scope of the invention includes the use of all of 65 eral lubricating oils in which there are incorporated about 0.0l%0.5% by weight of anthranilic acid and detergent additive combinations such as: 1% of neutral calcium mahogany sulfonate and 5% of neutral barium mahogany sulfonate; 5% of neutral calcium didodecybenzene sulfomate and 5% of neutral barium salt of the hydrolyzed reaction product of phosphorus pentasulfide with polyisobutene having an average molecular weight of 1000: 8% of a basic calcium salt of diodecylbenzene sulfonic acid prepared by carbonating at 6080 C. a mineral oil soluthe detergent additives and inhibitors previously illustrated 75 tion of the acid with five chemical equivalents of calcium 1 hydroxide in the presence of methyl alcohol as the promotor, and 8% of a neutral barium didodecylbenzene sulfonate; of the calcium detergent of Example 2 and 2% of the barium detergent of Example 0; 3% of the calcium detergent of Example D and 9% of the barium detergent of Example E.

The Air Oxidation Test results summarized in Table II illustrate the unusual oxidation stability of lubricant componsitions contining anthranilic acid and such a mixture of barium and calcium detergent additives.

The calcium and barium sulfonates used in the lubricant compositions indicated earlier as being especially preferred may be derived from either petroleum sulfonic acids or synthetic alkaryl sulfonic acids. Thus the barium sulfonate may be either barium mahogany or barium alkaryl sulfonate and the calcium sulfonate likewise may be either of these types. Further, the combination of calcium and barium sulfonates in one lubricant composition may include all possible combinaations of calcium, barium, mahogany sulfonates and synthetic alkaryl sulfonates.

What is claimed is:

1. A lubricating composition comprising a major proportion of a mineral lubricating oil, from about 0.1% to about 10% of an oil-soluble calcium salt of a sulfonic acid selected from the class consisting of petroleum sul- TABLE II.AIR OXIDATION TEST RESULTS [all percent addition by weight] An- Corro- Percent viscosity increase at end of test thrasioninperiod of- Test nilic hibitor Ca-detergent Bat-detergent sample acid of example R 72 96 120 144 166 hours hours hours hours hours 1 0.05 3 10.4% ofadditive None 10 14 47 227 601 of Example B. 2 0.05 3 None 12% ofadditive 9 79 215 484 of Example E. 3 0.05 2.5 5.8% ofadditive 5.4% ofadditive 7 10 13 15 17 of Example 13. of Example E. 4 0. 075 2 8.2% ofadditive 3% oiadditive 12 10 21 27 125 of Example 13. of Example E. 5 0.05 3 10.4% oiadditive None 10 14 47 227 004 of Example B. 6 0.05 3 None 12% of additive 11 23 107 232 451 of Example F. 7 0.05 3 4.50% of additive 4.44% ofadditive 9 12 10 16 of Example B. of Example F. s 0. 05 3 7% of additive of 4% ofadditive 9 10 11 14 10 Example B. of Example N 9 0.075 2 5.8% ofadditive 5.2% ofadditive 7 s 11 13 18 of Example B. of Example N. 10 0. 075 2 8.2% ofadditive 3% of additive 9 13 17 21 32 of Example B. of Example N. 11 0.05 3 None 11.5 ofadditive 8 55 226 500 of Example 0. 12 0.05 3 10.4% of additive None 12 207 566 of Example P. 13 0.05 3 5.6% of additive 5.75% oi additive 13 1s 1s 47 217 of Example I. of Example 0. 14 0.025 2 9.8% oi additive 2.28% oiadditivc 13 14 1s 22 23 of Example B. of Example 0.

Lubricant XIII: Parts fonic acids and alkaryl sulfonic acids; from about 0.1% SAE 30 mineral oil 100 to about 10% of an oil-soluble barium salt of an acid Anthranilic acid 0. selected from the class consisting of petroleum sul- Basic barium sulfonate of Example O (but prefonic acids, alkaryl sulfonic acids, and phosphorus acids pared from polydodecyl benzene sulfomc acid 50 obtained by reacting a polymer selected from the class instead of petroleum sulfonic acid) 8 consisting of isobutene polymers and chlorinated iso- Basic calcium sulfonate of Example B 2 butene polymers having a molecular weight from about Zinc dihexyl phosphorodithioate 1 200 to 100,000 with a phosphorus reagent selected from Lubricant XIV: the class consisting of phosphorus trichloride and phos- SAE 30 mineral oil 100 phorus pentasulfide; and a small amount, suflicient to in- Anthranilic acid 0.3 crease the resistance to deterioration of said lubricating Basic barium sulfonate of Example 0 (but precompositions due to the presence therein of said calcium pared from polydodecyl benzene sulfonic acid and barium salts, of anthranilic acid.

instead of petroleum sulfonic acid) 6 2. A lubricating composition comprising a major pro- Basic calcium sulfonate of Example P 1.5 portion of a mineral lubricating oil, from about 0.1% to Zinc isopropyl hexyl phosphorodithioate 1 about 10% of an oil-soluble, basic calcium salt of an Lubricant XV: alkaryl sulfonic acid; from about 0.1% to about 10% of SAE 30 mineral oil 100 an oil-soluble, basic barium salt of a phosphorus acid ob- Anthranilio acid 0.3 tained by reacting a chlorinated polyisobutene having a Basic barium sulfonate of Example E (but premolecular weight from about 500 to about 10,000 with pared from a 50-50 mixture of mahogany and phosphorus trichloride; and a small amount, sufficient to polydodecyl benzene sulfonates) 5 increase the resistance to deterioration of said lubricat- Basic calcium sulfonate of Example P 3 ing composition due to the presence therein of said calci- Calcium phenolic corrosion inhibitor of Exum and barium salts, of anthranilic acid.

ample Q 2 3. A lubricating composition comprising a major proportion of a mineral lubricating oil, from about 0.1% to about 10% of an oil-soluble, basic calcium salt of an alkaryl sulfonic acid; from about 0.1% to about 10% of an oil-soluble, basic barium salt of a phosphorus acid obtained by reacting a polyisobutene having a molecular Weight from about 500 to about 10,000 with phosphorus pentasulfide; and a small amount, suflicient to increase the resistance to deterioration of said lubricating composition due to the presence therein of said calcium and barium salts, of anthranilic acid.

4. A lubricating composition comprising a major proportion of a mineral lubricating oil, from about 0.1% to about 10% of an oil soluble calcium salt of an acid selected from the class consisting of petroleum sulfonic acids and alkaryl sulfonic acids, from about 0.1% to about 10% of an oil soluble barium salt of an acid selected from the class consisting of petroleum sulfonic acids and alkaryl sulfonic acids, and a small amount, sufiicient to increase the resistance to deterioration of said lubricating compositions due to the presence therein of said calcium and barium sulfonates, of anthranilic acid.

5. The lubricating composition of claim 4 characterized further in that the calcium sulfonate and barium sulfonate are each derived from a mahogany acid.

6. The lubricating composition of claim 4 characterized further in that the calcium sulfonate and barium sulfonate each contain stoichiometrically excessive amounts of metal.

7. The lubricating composition of claim 4 characterized further in that it contains from about 0.01% to about 5.0% of a calcium salt of an alkyl phenol-formaldehyde condensation product.

8. The lubricating composition of claim 4 characterized further in that the calcium sulfonate and barium sulfonate are each carbonated basic metal sulfonates.

References Cited in the file of this patent UNITED STATES PATENTS 1,975,755 Hoyt et a1. Oct. 2, 1934 2,151,300 Moran et al Mar. 21, 1939 2,3 69,090 Trautman Feb. 6, 1945 2,390,943 Kavanagh et a1 Dec. 11, 1945 2,629,693 Barton et a1 Feb. 24, 1953 2,723,234 Asefr' et al Nov. 8, 1955 2,736,701 Nefi Feb. 28, 1956 2,815,370 Hutchings et a1 Dec. 3, 1957 2,844,535 Blumer July 22, 1958 2,846,466 Crosby et a1 Aug. 5, 1958 2,849,398 Moody et a1 Aug. 26, 1958 OTHER REFERENCES Georgi: Motor Oils and Engine Lubrication, 1950, Reinhold Publishing Corporation, pages 170190 pertinent.

Claims (1)

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL, FROM ABOUT 0.1% TO ABOUT 10% OF AN OIL-SOLUBLE CALCIUM SALT OF A SULFONIC ACID SELECTED FROM THE CLASS CONSISTING OF PETROLEUM SULFONIC ACIDS AND ALKARYL SULFONIC ACIDS; FROM ABOUT 0.1% TO ABOUT 10% OF AN OIL-SOLUBLE BARIUM SALT OF AN ACID SELECTED FROM THE CLASS CONSISTING OF PETROLEUM SULFONIC ACIDS, ALKARYL SULFONIC ACIDS, AND PHOSPHORUS ACIDS OBTAINED BY REACTING A POLYMER SELECTED FROM THE CLASS CONSISTING OF ISOBUTENE POLYMERS AND CHLORINATED ISOBUTENE POLYMERS HAVING A MOLECULAR WEIGHT FROM ABOUT 200 TO 100,000 WITH A PHOSPHORUS REAGENT SELECTED FROM THE CLASS CONSISTING OF PHOSPHORUS TRICHLORIDE AND PHOSPHORUS PENTASULFIDE; AND A SMALL AMOUNT, SUFFICIENT TO INCREASE THE RESISTANCE TO DETERIORATION OF SAID LUBRICATING COMPOSITIONS DUE TO THE PRESENCE THEREIN OF SAID CALCIUM AND BARIUM SALTS, OF ANTHRANILIC ACID.