US3067136A - Lubricating compositions - Google Patents

Description

ilnited rates Patent Patented Dec. 4, less 3,067,136 LUBRIQATEJG CGMPOSITEONS Thomas W. Martinek, Phoenix, Ariz., assignor to The Pure Oil Company, Chicago, 11L, a corporation of 01110 No Drawing. Filed Oct. 26, 1959, fier. No. 848,563 14 Ciaims. (Cl. 252-32) This invention relates to salts of complex, polyfunctional, high-molecular-weight, aromatic acids derivedfrom selected petroleum fractions. More particularly, the invention relates to lubricating compositions, particularly grease compositions, comprising mineral lubricating oil and salts of complex, polyfunctional, high-molecularweight, aromatic acids. My copending application entitled, Conversion of Selected Petroleum Fractions, filed June 12, 1959, and bearing Serial No. 819,932 (now abandoned), describes completely a method of prepara tion of these complex acids and the subject matter of this copending application is hereby incorporated by reference. Application Serial No. 220,344, filed August 1, 1962, entitled Process and Product is a continuation in part thereof.

In accordance with this invention, it has been dis-' covered that the ammonia, amine, or metal salts of complex, polyfunctional, high-molecular-weight, aromatic acids are good gelling agents for greases and may be used as thickening agents for oleaginous base stocks. Although the art teaches the preparation of dibasic acids from pure aromatic compounds by reaction with alkali metals, followed by carbonization, the nature of the selected petroleum fractions from which the source hydrocarbons for the preparation of the instant complex acids are prepared is so complex that these materials have not been elfectively used. The state of the art on the preparation of these compounds is set forth in my copending application supra. The essential feature of the invention, therefore, comprises the discovery that the salts of complex, polyfunctional, high-molecular-weight, aromatic acids can be used in lubricating compositions to impart thereto thickened qualities and form a true gelled-grease consistency. Furthermore, it has been found that the compositions prepared in accordance with this invention are shear-stable, water-resistant and give high grease yields.

Accordingly, it becomes a primary object of this invention to provide lubricating compositions containing salts of complex, polyfunctional, high-molecular-weight, aromatic acids.

Another object of this invention is to provide lubricating compositions containing an oleaginous vehicle and salts of complex, polyfunctional, high-inolecular-weight, aromatic acids.

Another object of this invention is to provide a process for preparing lubricating compositions containing salts of complex, polyfunctional, high-molecular-weight, aromatic acids.

Another object of this invention is to provide lubricating compositions containing ammonium salts of complex, polyfunctional, high-molecular-weight, aromatic acids.

Another object of this invention is to provide amine salts of complex, polyfunctional, high-molecular-weight, aromatic acids.

Another object of this invention is to provide metal salts of complex, polyfunctional, high-molecular-weight, aromatic acids.

A further object of this invention its to provide lubricating compositions containing salts of metals of Groups I, II and Ill of the Periodic Chart of Atoms (1941) prepared from complex, polyfunctional, high-molecularweight, aromatic acids.

As stated in the aforeidentified application, the starting materials used to prepare the polyfunctional acids are adequately described as those aromatic materials separated from mineral lubricating oils and their fractions, i.e., those aromatics obtained in the manufacture and refining of neutral oils andbright stocks during treatment with a selective solvent designed to extract the predominantly aromatic materials from the paraffinc materials. Solvent extracts resulting from the treatment of mineral lubricating oils for the purpose of separating non-aromatic hydrocarbons (the rafiinate and finished oil) from the aromatic hydrocarbons (the extract and waste product) may be used and are preferred as starting materials.

Since the general process of refining mineral lubricating oils in which the solvent extracts are obtained is well known, it is only necessary for present purposes to describe a typical'procedure for obtaining same and give some examples by Way of illustration.

In a typical operation, desalted crude oil is first charged to a distillation unit where straight-run gasoline, two grades of naphtha, kerosine, and virgin distillate are taken off, leaving a reduced crude residue. The reduced crude is continuously charged to a vacuum distillation unit where three lubricating oil distillates are taken off as side streams, a lightdistillate is taken off as overhead, and a residuum is withdrawn from the bottom of the tower. The residuum is charged to a propane-deasphalting unit wherein propane dissolves the desirable lubricating oil constituents and leaves the asphaltic materials. A typical vacuum residuum charge to the propane-deasphalting unit may have an API gravity of 12.9", viscosity SUS at 210 F. of 1249, flash 585 F., fire 650 F., C.R. of 13.9 weight percent, and may be black in color. The deasphalted oil may have an API gravity of 21.5 to 21.8", viscosity SUS at 210 F. of -175, NPA color 6-7, flash 575 F., fire 640 F., and C.R. of 1.7-2.0. The deasphalted oil and various lubricating oil distillates from the reduced crude are subjected to solvent extraction for the separation of non-aromatic from aromatic constituents prior to use. The refined oil or rafiinate from the extraction processes is used per se, or as blending stock, for lubricating oils, and the solvent extract, predominating in complex aromatic constituents, is distinctively used in accordance with this invention.

For example, a crude oil from an East Texas field with an API gravity of 33.1 was topped to remove such light fractions as gasoline, naphtha, kerosine, and a light lubricating distillate. The vacuum residue was a reduced crude having a viscosity of 1251 SUS at 210 F., 2.2 percent sulfur, and an API gravity of 12.6. After propanedeasphalting, the oil had a viscosity of 174 SUS at 210 F. and an API gravity of 21.7. This deasphalted oil was treated with phenol to produce a raifinate from which an aviation lubricating oil could be prepared. The oil extracted by phenol treatment, after removal of phenol, is ready for use as the starting material in accordance with this invention.

Solvents other than phenol may be used to obtain the extraction product used in accordance with this invention, for example, liquid sulfur dioxide, nitrobenzene, Chlorex, chlorophenol, trichloroethylene, cresylic acid, pyridine, furfural, or the Duo-Sol solution (comprising liquid propane and cresol) may be used. When using phenol, it is possible to vary the characteristics of the extract and raffinate products considerably by adjustment of the amount of water present. A rafiinate of relatively low viscosity index can be obtained by using a water solution of phenol during the extraction, and a raflinate of high viscosity index can be obtained by using anhydrous phenol. Following are the physical characteristics of typical extract products, from lubricating oil stocks derived from various crude oils and other source hydrocarbon materials, which may be used in accordance with this invention.

3 TABLE I Sources and Physzcal Characterzstlcs of Solvent Extracts Crude API Sp. Gr. Vis./ Vis./ Vis./ F. F. Iodine Percent Percent Ext. No. Source Solvent Grav. @10 F. 100 F 130 F. 210 F. V.I. Pour Flash Fire (vlz lo (1R. Sulfur 1 East Tex 11.1 282 2- 15. 4 285 3- 12. 6 310. l 4- 14. 6 313 5- 15. 4 372 6--- 13. 7 355 7--- 8.6 616 8 10.5 172.1 9 Sante Fe 1.0.2 371 Springs.

Furfural 13. O 1, 500 Chlorex 12. 2 1, 365 Nitrobenzene 10.0 1, 500 Propanecresoh 14. 4 1, 500 13. 6 41. 7 l3. 6 200 8. 9 569 14. 9 50.2 25 13. 976 25, 000 341 17 +65 530 610 5. 76 2. 36

The solvent extracts from lubn'cating oils used as starting materials for this invention have the following general properties and characteristics:

' TABLE H Characteristic: Range of value Gravity, API 8.0-15.0 Gravity, sp., 380/155 C 0.9550-1,000 Viscosity SUS 100 F 350-25,000 (ext.) Viscosity SUS 130 F 140-19,000 Viscosity SUS 210 F 200-1500 Viscosity index 101-+39 Pour point (max) +35-100 Color, NPA +2-5D Molecular Weight, average 320-600 Boiling point (initial), F. 300-1000 Boiling point (end), F. 400-1200 Sulfur, percent wt 2.0-4.5

Sulfur compounds, percent Wt. 20-50 Aromatics and thio-compounds 50-90 Thio-compounds 14-40 Neutral aromatic hydrocarbons 40-51 AV. N0. of rings/mean arom.

mol 1.7-3.5 H/C Wt. ratio 0.1160.136 H/C atom ratio, whole sample 1,383-1.622 H/ C atom ratio, aromatic portion 1.2891.500 Nearest empirical formula C H 'C H The gravities of the extracts in general increase with increase in the viscosity of the raffinate at a constant viscosity index. Stated otherwise, the gravities of these extracts increase with decrease in viscosity index of the raflinate at a constant viscosity. For the production of 100:5 V.I. neutral oils, the viscosities of the extracts increase with increase in stated viscosities of the neutral oils (rafllnates). The pour points of extracts are high and are affected by changes in the depth of extraction. The sulfur contents are also affected by the depth of extraction. The solvent extracts are characterized by containing aromatic and sulfur compounds in the range of 70-90%, the remainder being principally saturates, or material behaving as saturates, together with a minor proportion of from 3.0 to 6.0% of organic acids. The organic acids present are not susceptible to extraction by the use of aqueous strong caustic because of emulsion formation. Very little asphaltic material is present in solvent extracts and they contain no materials volatile at room temperatures. 7

The materials shown in Tables I and II are merely illustrative and the invention is not to be limited thereby.

It is apparent that the composition and characteristics of the thickening agents prepared in accordance with this invention will vary somewhat depending on the concentration and types of acid derivatives prepared from the complex, polynuclear, aromatic hydrocarbons in the solvent extracts used. In such complicated mixtures as solvent extracts from petroleum oils and solvent extracts from lubricating oil fractions, the content of reactable complex aromatic materials may vary from about 50 to 100% by weight. Accordingly, it is to be understood that the invention is broadly applicable to the use of any petroleum fraction which contains at least about 30%by weight of reactable, complex, polynuclear, aromatic hydrocarbons for the preparation of the salts of this invention. The most reactable types of complex aromatic hydrocarbons are found in high concentrations in solvent extracts obtained in the manufacture of neutrals and bright stock, all of which materials are to be understood as suitable starting materials in this invention. However, it is to be further understod that the invention is particularly applicable to any solvent extract obtained from the refining of mineral lubricating oils for the purpose of separating nonaromatic and aromatic hydrocarbons, that is, where the solvent exerts a preferential selectivity for the aromatic constituents. The extracts as described in said copending application are substantially freed of solvent, e.g., the phenol extracts are dephenolized by steam stripping so that they contain practically no solvent.

Reference is made to the copending application aforeidentified for a disclosure of the method of preparing the polyfunctional acidic compounds which are reacted with ammonia, amines or a metal to form the thickening agents of this invention. In this regard, the starting material is first reacted with an alkali metal in elementary form. For this purpose sodium, lithium, potassium, rubidium and cesium, and mixtures and alloys of these, may be used, that is members of Group IA of the Periodic Chart of the Atoms, Hubbard, 1941, Revised Chart. About 30 parts of solvent extract are used per 1 to 5 parts of alkali metal. The reaction may be carried out at temperatures as low as 60 C. and as high as C. The prior art solvents for this type of reaction, such as dimethyl glycol ether, dimethyl ether, methyl alkyl ethers, dialkyl glycol ethers, tetrahydrofuran, dioxane and trimethylamine may be used.

The reaction of the alkali metal with the reactive, complex, aromatic components does not occur unless steps are taken to overcome the eifects of certain reactive impurities in the complex mixture which normally coat the sodium surface and prevent reaction. The undesirable reactive impurities present in the mineral oil mixture may be traces of water, organic acids (such as naphthenic acids), phenols, and other oxygen-containing compounds, mercaptans and other sulfur compounds, and nitrogen-containing compounds. The reaction can be advantageously effected if fresh sodium surfaces are continuously exposed until all undesired reactive impurities have reacted, or if suflicient sodium surface to react with all such impurities plus a moderate excess is used. Another expedient is to use a large excess of sodium metal. It appears that once the undesired reactive impurities have reacted, the desired reaction can take place on the excess clean sodium surface. It also appears that once the complexing reaction occurs, the oil solution of complex begins to dissolve the undesired reaction product coating from the sodium surface, in effect cleaning the particle surface and rendering more surface available for reaction.

The reaction is difficult to start unless an excess of sodium and fresh sodium surface is used. Certain expe'dients have been found advantageous. Among these are continuous shearing of the sodium particles until the reaction starts. This has been accomplished with a Brookfield counter-rotating stirrer. Other shearing or crushing devices, such as a Waring Blendor, colloid mill, muller, ball-mill, and the like, also may be used. Even with continuous shearing or crushing, many minutes and sometimes hours are required before the desired complexing reaction starts. The length of time required depends on the relative amounts of impurities present, and the extent of sodium surface made available. The inhibiting or dominating effect of reactive impurities may be one reason why petroleum hydrocarbon sources were not exploited as starting materials for this type of reaction.

Another expedient found advantageous in accordance with my copending application resides in the use of preformed sodium dispersion in an inert liquid. Such dispersions and their preparation are well known in the art. A large excess of dispersed sodium must be used to initiate the reaction, unless steps are taken to remove the coating of undesired reaction products from the sodium surface. Such steps include the use of mills.

Still another expedient, and the preferred one, is the actual preparation of a sodium dispersion in the solvent extract to be reacted. The undesirable impurities appear to completely react with the sodium during preparation of the dispersion, and as a consequence, clean sodium surface is available for the desired reaction as soon as the reaction solvent is mixed with the sodium-reactivecomponent mixture. The desired reaction then is practically instantaneous and proceeds smoothly and rapidly to completion with only a slight excess of sodium.

When the reaction with the alkali metal is complete, as evidenced by its dissolution, the reaction mixture is treated with carbon dioxide, either at about the same or a different temperature as was used during the reaction with the alkali metal. The reaction mixture is next washed with water and allowed to separate into a solvent phase and a water phase. Several applications of 1 volume of water per 5 volumes of reaction mixture may be used and the water layers collected. Counter-cur rent water-washing may be used. The resulting water phase is acidified with an acid such as a hydrochloric, sulfuric acid, or phosphoric acid. This causes the polybasic, polynuclear aromatic acids to separate or precipitate from the aqueous mixture.

EXAMPLE I A mixture of polybasic acids from aromatic extract oil, derived from a petroleum lube oil stock by phenol extraction in the preparation of 170 vis., 100 V1. neutral oil, was prepared by the following procedure: A solution of 100 g. of aromatic oil in 675 cc. of dry tetrahydrofuran was placed in a 210(l-cc. flask equipped with a Brookfield counter-rotating stirrer and gas-inlet and -outlet. The solution was cooled and maintained at l0-30 C. while 8.3 g. of metallic sodium in the form of A cubes were added, after which cooling was maintained during a two-hour reaction period. No complex formation appeared to occur until approximately 25 minutes had elapsed. Thereafter, a strong color change was noted and the reaction appeared to proceed relatively rapidly.

After stirring for two hours, the mixture was cooled to -60 C. while an excess of carbon dioxide gas was introduced. The color was discharged by reaction with carbon dioxide, but no precipitation was noted. The unreacted sodium (5.1 g.) was removed, the tetrahydrofuran was stripped from the reaction mixture by applying a vacuum, after which the remaining liquid was combined with ether and washed with water.

The resulting aqueous phase was acidified and washed with ether to recover the free acids and other reaction products. About 89% W. of the original oil feed stock was recovered, and about 11% had reacted to form the acidic product of this invention. The product had an indicated average molecular weight of 686 and a saponification value of 171. The calculated equivalent weight is 328 indicating 2.1 acid groups per molecule. However, the true average molecular weight probably was somewhat lower than 686, the indicated average molecular weight being higher than actual because of molecular association in the benzene solvent during its determination. A portion of the complex acids was reacted with an excess of liquid ammonia. The resulting ammonium salts were separated by crystallization. This product, when added to mineral oil in a concentration of about 10%, exhibited a marked thickening action.

EXAMPLE II Another portion of the acid product from Example I was reacted with an excess amount of methylamine to form the methylamino salts. This product, when added to a mineral lubricating oil, exhibited thickening qualities.

EXAMPLE III Another portion of the acid product from Example I is reacted with dodecylamine. The resulting solid product is added to a lubricating oil in an amount of about 5% by weight to form a grease.

EXAMPLE IV In still another experiment, 10% gms. of solvent extract and 675 ml. of dry tetrahydrofuran were charged to a one-liter, 3-necked flask equipped with a stirrer, thermometer pressure-equalized drop-funnel, gas-inlet with rotometer, and gas-outlet. A dry nitrogen atmosphere was maintained. Approximately gms. of Alundum balls 7 diameter were charged and agitation started. The solution was cooled to 20 C. and 8.3 gms. sodium as a 20% dispersion in toluene were added. After 5 minutes, no reaction had occurred and the solution was allowed to warm. After 25 minutes, the temperature had risen to -7 C. and a few particles of sodium appeared to be reacting, i.e., the deep color of the complex was seen to be forming on the surface of a few particles when agitation was momentarily stopped. Within an additional 17 minutes, the reaction was proceeding smoothly and the dry carbon dioxide atmosphere was introduced to the flask in excess at l8 C. over a period of 78 minutes. The reaction mixture was worked up as in the previous example after the excess sodium was destroyed with water. Hydrogen evolution from the remaining sodium indicated that only 48% of the sodium had reacted. Approximately 84.5% of the oil was recovered, indicating 15.5% had reacted. The acids recovered weighed 22.5 gins. and had a saponification value of 241, indicating an equivalent weight of 233, and contained 2.8% sulfur. With a similar experiment, the acids recovered had a soponifioation value of 323, indicated 173 equivalent weight, with an indicated average molecular weight (cryoscopic) of 600. They contained 3.0% sulfur. The ratio of molecular weight to equivalent weight was 3.4, indicating a mixture containing acids with more than 2 acid groups per molecule. A portion of the complex acids is reacted with an excess of liquid ammonia. The resulting ammonium salts were separated by crystallization. This product, when added to mineral oil in a concentration of about 10%, exhibited a marked thickening action.

EXAMPLE V A portion of the acid product from Example IV is reacted with an excess amount of methylamine to form the methylamino salts. This product, when added to a mineral lubricating oil, exhibited thickening qualities.

EXAMPLE VI Another portion of the reaction product from Example IV is reacted with dodecylamine. The resulting solid product is added to a lubricating oil in an amount of about by weight to form a grease.

EXAMPLE VII A 195 g. portion of polybasic polynuclear acids having a saponification value of 287 and an average molecular weight of 750 prepared under conditions similar to Example I, is dissolved in 400 g. of extract oil derived during the preparation of a bright stock oil. During the solution, the mixture was maintained at a temperature of about 180 to 200 F. After solution has been completed, 38 g. of hydrated lime is added as a suspension in 400 g. of 200 vis. neutral oil. Following this, the temperature of the mass is raised slowly, while stirring, to about 300 F., thereby dehydrating the mixture. A grease composition is thereby formed which is cut back to the desired consistency by adding an additional 900 g. of oil while cooling slowly from 300 F. to about 200 F. The resulting grease containing about 8 weight percent of the calcium salt of the complex polyfunctional high molecular weight aromatic acids is clear, plastic, shear stable, and water-resistant.

EXAMPLE VIII A 20.6 g. portion of mixed complex acids having a saponification value of 272 and an average molecular weight of about 940, prepared in accordance with the method of Example IV, is neutralized with alcoholic sodium hydroxide to make 22.7 g. of the corresponding sodium salts. After the alcohol has been stripped from the solution, the mixture of sodium salts is an amber powder which is insoluble in benzene and hexane. g. of the mixed sodium salts are added to 220 g. of 200 vis. neutral oil and dissolved therein by heating under an atmosphere of nitrogen. The hot solution is then poured onto a cold, polished-steel plate whereupon a firm gel forms. The gel after cooling is removed from the plate and worked to grease consistency by milling.

EXAMPLE IX A portion of the mixed acids from Example IV is dissolved in tetrahydrofuran and neutralized with soda. Following this, the resultant g. of product is diluted with 200 g. of 200 vis. neutral oil and the tetrahydrofuran is evaporated to leave a grease.

EXAMPLE X A portion of 200 vis. neutral oil is combined with a portion of aromatic solvent extract oil and the sodium salt of the mixed polyfunctional acids of this invention as described in Example I are prepared in situ therein. A grease results when the active solvent is stripped from the resulting solution. Alternatively, the neutral oil or other mineral or synthetic oil can be added after the metal aromatic complex is carbonated. Sodium greases having high yield have been prepared in this way.

In carrying out the instant invention, it is contemplated that the base material used to form the salts may be ammonia, amines, or any reactable metal. The amines may be defined as any substituted-ammonia compound capable of reaction with a carboxylic acid to form a salt or complex therewith, i.e., primary, secondary and tertiary aliphatic (including cycloaliphatic), aromatic and heterocyclic amines. Examples are aliphatic and cycloaliphatic amines, such as methylamine, ethylamine, diethylamine, propylamine, isopropylamine, butylamine, isobutylamine, t-butylamine, diethylamine, amylamine,

tributylamine, isoamylamine, hexylamine, isohexylamine, ethanolamine, diethanolamine, triethanolamine, isopropanolamine, trimethylamine, trimethylenamine, tetrarnethylenediamine, laurylamine, hexadecylamine, ethylenediamine, diethylenetriamine, triethylene-tetramine, cyclohexylamine, dicyclohexylamine, tristerylamine, guanidine, dodecenylamine, oleylamine, morpholine, eicosenylamine, N-oleyl, N-prcpanolamine, etc. Various known mixtures of amines may also be employed, particularly the mixtures of amines obtained by converting the higher fatty acids into the corresponding amine. Such mixtures include castor amine obtained from castor oil, which cons'ists mostly of ricinoleoamine and oleoamine. Another mixture is cocoamine obtained from coconut oil fatty acids, which contains mostly lauryl amine and homologous amines. Similar mixtures include amines prepared from corn oil acids, cottonseed oil acids, palm oil acids, etc. Aromatic amines, such as aniline, diphenyl aniline, and triphenyl aniline, are also suitable. Mixed amines, such as methylcyclohexylamine, monomethylaniline and ethylbutylamine may be used.

The metal compounds used to form the metal salts of the complex, polyfunctional, high-molecular-weight,-

aromatic acids include such compounds as oxides, hy-

droxides, halides and sulfides of lithium, sodium, potassium, copper, silver, magnesium, calcium, zinc, strontium, cadmium, barium, aluminum, zirconium, antimony, chromium, molybedenum, tungsten, iron, cobalt and nickel. Preferred species include sodium hydroxide, potassium hydroxide, copper oxide, magnesium hydroxide, calcium oxide, calcium hydroxide, barium oxide, barium hydroxide octahydrate, aluminum hydroxide, molybdenum oxide, ferric hydroxide and cobalt oxide. With the more reactive metals, such as sodium, potassium and cesium, the free metal may be reacted directly.

In preparing the salts and soaps of this invention, it is only necessary to contact the purified or impure complex, polyfunctional, aromatic acids with the neutralizing or salt forming materials under conditions to promote the formation of the desired salt or soap. Various mol ratios of aromatic acid to neutralizing agent may be used, i.e., the amount of neutralizing agent may be less than stoichiometric amounts, equal to stoichiometric amounts or greater than stoichiometric amounts. The reaction temperature may be varied in accordance with the best known techniques for forming salts and soaps. The temperatures used may vary from about 10 F. to 500 F. and an inert atmosphere may be maintained over the reaction mixture during heating. Pressures up to about p.s.i.g. may be applied where the neutralizing agent is volatile. The reaction may be carried out in the liquid phase where the neutralizing agent is a liquid or if solid neutralizing agents are used various solvents such as Water, alcohols, ethers, ketones and aliphatic hydrocarbons may be necessary. The known techniques for carrying out saponification and neutralization reactions whereby organic monoand polycarboxylic acids are transformed into salts and soaps may be applied. As in the grease-making art, the oil solution of complex, high-molecular-weight, aromatic carboxylic acids may be reacted with the metal base or amine to form the salts or soaps in situ.

As seen from the foregoing description, the invention relates generally to lubricating compositions comprising a mineral lubricating oil and a salt or soap of a polynuclear aromatic carboxylic acid derived from petroleum fractions rich in polynuclear aromatic compounds. These polycarboxylic acids are characterized by their physical properties and source. The compositions are unusual in their yield, shear stability, thermal stability, water resistance, oxidation resistance, radia tion resistance and high-temperature performance. A high degree of water resistance is obtained through the use of the lithium and calcium salts of the polycarboxylic acids of this invention. Increased thermal stability can be achieved by hydrogenating or dehydrogenating the olefinic constituents of the polycarboxylic acids to form naphthenic or completely aromatic condensed nuclei, respectively. In adition to imparting increased thermal stability, dehydrogenation results in the production of greases having high radiation resistance. The lubricating fiuid component may be any of the mineral or synthetic oils known to be useful in making greases.

Various proportions of the salts of this invention may be used with an oleaginous carrier to form compositions having desirable properties. The salts may be used in concentrations of up to 20% by weight in mineral lubricating oils for purposes of gelling or thickening the carrier. Generally about to 20% by weight of the salts will function as gelling agents in mineral lubricating oils. Synthetic lubricants may require less than 5.0%, that is, in the order of 1 to 4% for the purpose of enhancing the flow characteristics. Grease compositions are preferably made by using 510% by weight of lithium and calcium salts to impart a high degree of water resistance.

The oleaginous materials include mineral lubricating oils, fatty oils, synthetic oils. Mineral oils naphthenic, parafiinic, or mixed base origin may be used. Generally for purposes of grease-making, highly refined oils are preferred, such as neutrals and bright stocks and their mixtures, which have been dewaxed, solvent extracted and clay contacted as is Well known in the art. It is also contemplated that the salts of this invention will find utility in other compositions such as fuel' oils, gasoline, naphthas and spindle oils. Other addends such as oxidation inhibitors, rust inhibitors, viscosity index improvers, extreme-pressure agents, pour point depressants, corrosion inhibitors, oiliness agents, and the like may be incorporated in compositions containing the salts of this invention. Having thus described the invention, the only limitations attaching thereto appear in the appended claims.

What is claimed is:

l. A lubricating composition comprising a major portion of an oleaginous vehicle and a minor portion of a salt of complex carboxylic acids derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, by metalation of said solvent extracts to form the alkali metal adduct, carbonation of said adduct to form the alkali metal salt of the corresponding carboxylic acid, acidification of said salt to form the free carboxylic acid and conversion of said carboxylic acid to said salt.

2. A lubricating composition in accordance with claim 1 in which said complex carboxylic acids are characterized by having an average molecular weight of above about 320, which contain about 2.0 to 4.5 weight percent of sulfur and have an average of about 1.7 to 3.5 aromatic rings per mean aromatic molecule.

3. A lubricating composition in accordance with claim 2 in which said complex carboxylic acids are prepared by reacting phenol extract, obtained in the phenol extraction of mineral lubricating oils, with metallic sodium to form the sodium adduct, carbonating said sodium adduct to form a sodium salt of the corresponding carboxylic acids and acidifying said salts to form the free acid.

4. A lubricating composition in accordance with claim 1 in which said salt is a member of the group consisting of ammonium salts, amine salts wherein said amine has from 1 to 20 carbon atoms and metal salts.

5. A lubricating composition in accordance with claim 1 in which about 1 to 20% by weight of said salt is present based on the total weight of the composition.

6. A grease composition comprising a major portion of a mineral lubricating oil vehicle and about 520% by weight of an ammonium salt of complex carboxylic acids, derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selec- 10 tive for aromatic compounds, by metalation of said solvent extracts to form the alkali metal adduct, carbonation of said adduct to form alkali metal salt of the corresponding carboxylic acid, acidification of said salt to form the free carboxylic acid and reaction of said free carboxylicacid with ammonia.

7. A grease composition comprising a major portion of a mineral lubricating oil vehicle and about 520% by weight of an amine salt of complex carboxylic acids, derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, by metalation of said solvent extracts to form the alkali metal adduct, carbonation of said adduct to form the alkali metal salt of the corresponding carboxylic acid, acidification of said salt to form the free carboxylic acid and reaction of said free carboxylic acid with an amine having 1 to 20 carbon atoms.

8. A grease composition comprising a major portion of a mineral lubricating oil vehicle and about 520% by weight of an alkali metalsalt of carboxylic acids derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds by metalation of said solvent extract to form the alkali metal adduct and carbonation of said adduct to form the alkali metal salt of the corresponding carboxylic acid.

9. A grease composition in accordance with claim 8 in which said alkali metal salt of said complex carboxylic acid is prepared in situ in said mineral lubricating oil vehicle.

10. A grease composition comprising a major portion of a mineral lubricating oil vehicle and about 520% by weight of an alkaline earth metal salt of complex carboxylic acids, derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, by metalation of said solvent extracts to form the alkali metal adduct, carbonation of said adduct to form the alkali metal salt of the corresponding carboxylic acid, acidification of said salt to form the free carboxylic acid and reaction of said free carboxylic acid with an alkaline earth metal base.

11. A thickened lubricant comprising a major portion of a mineral lubricating oil containing about 10% by weight of an ammonium salt of complex carboxylic acids derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, by metalation of said solvent extracts to form the alkali metal adduct, carbonation of said adduct to form the alkali metal salt of the corresponding carboxylic acid, acidification of said salt to form the free carboxylic acid and reaction of said acid with liquid ammonia, said carboxylic acids being characterized by having an average molecular weight of above about 320, containing about 2.0 to 4.5 weight percent of sulfur and having an average of about 1.7 to 3.5 aromatic rings per mean aromatic molecule.

12. A grease composition comprising a major portion of a mineral lubricating oil containing about 5% by weight of the dodecylamine salt of complex carboxylic acids derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, by metalation of said solvent extracts to form the alkali metal adduct, carbonation of said adduct to form the alkali metal salt of the corresponding carboxylic acid, acidification of said salt to form the free carboxylic acid and reaction of said acid with dodecyl amine, said carboxylic acids being characterized by having an average molecular weight of above about 320, containing about 2.0 to 4.5 weight percent of sulfur and having an average of about 1.7 to 3.5 aromatic rings per mean aromatic molecule.

13. A grease composition comprising a major portion of a mineral lubricating oil containing about 8% by Weight of the calcium salt of complex carboxylic acids derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, by metalation of said solvent extracts to form the alkali metal adduct, carbonation of said adduct to form the alkali metal salt of the corresponding carboxylic acid, acidfication of said salt to form the free carboxylic acid and reaction of said acid with hydrated lime, said carboxylic acids being characterized by having an average molecular weight of above about 320, containing about 2.0 to 4.5 Weight percent of sulfur and having an average of about 1.7 to 3.5 aromatic rings per mean aromatic molecule.

14. A grease composition comprising a major portion of a mineral lubricaL ng oil containing about 11% by Weight of the sodium salt of complex carboxylic acids derived from solvent extracts obtained in the solvent refining of mineral lubricating oils with a solvent selective for aromatic compounds, by Inetala-tion of said solvent extracts to form the alkali metal adduct, carbonation of said adduct to form the alkali metal salt of the corresponding carboxylic acid, acidification of said salt to form the free carboxylic acid and reaction of said acid with sodium hydroxide, said carboxylic acids being characterized by having an average molecular weight of above about 320, containing about 2.0 to 4.5 Weight percent of sulfur and having an average of about 1.7 to 3.5 aromatic rings per mean aromatic molecule.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Conant et al.: J.A.C.S., vol. 50 (1928), pp. 542-550.

Claims (1)

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR PORTION OF AN OLEAGINOUS VEHICLE AND A MINOR PORTION OF A SALT OF COMPLEX CARBOXYLIC ACIDS DERIVED FROM SOLVENT EXTRACTS OBTAINED IN THE SOLVENT REFINING OF MINERAL LUBRICATING OILS WITH A SOLVENT SELECTIVE FOR AROMATIC COMPOUNDS, BY METALATION OF SAID SOLVENT EXTRACTS TO FORM THE ALKALI METAL SALT OF THE CORRESPONDING CARBOXYLIC FORM THE ALKALI METAL SALT OF THE CORRESPONDING CARBOXYLIC ACID, ACIDIFICATION OF SAID SALT TO FORM THE FREE CARBOXYLIC ACID AND CONVERSION OF SAID CARBOXYLIC ACID TO SAID SALT.