US2585520A - Lubricating compositions containing highly basic metal sulfonates - Google Patents

Description

Patented Feb. 12, 1952 UNITED STATE LUBRICATING COMP HIGHLY BASIC M OSITIONS CONTAINING ETAL SULI OBTAlIJES Paul R. Van E55 and Hulbert a. Sippie, Berkeley,

Calif., assignors-to Shell Development Company, San Francisco, Calii'., a corporation of Delaware No Drawing. Application 3, 1943, Serial No. 63,446

11 Claims.

This invention relates to compounded oleaginous compositions. More particularly, it deals with'mineral lubricating oil compositions containing oil-soluble sulfonates. The invention also relates to new oil-soluble sulfonates which are particularly useful in the production of compounded lubricating oils andother oleaginous compositions. It is also concerned with new highly basic sulfonate salts and their preparation.

It is known that in modern internal combustion engines, including diesel engines and aviation engines, as well as ordinary automotive spark ignition engines, various products of combustion, fuel and/or oil degradation, condensation, polymerization, and the like, are generally formed which result in piston ring sticking, valve sticking, and corrosion of various metal parts of the combustion zone and auxiliary-parts functioning therewith. Accumulation of lacquer and/or carbonaceous deposits on the rings and grooves and on valve stems and valve guides ap pears to be the most probable reason for ring and valve sticking. The production of acidic bodies by the combustion of the fuel and/or by the degradation of the lubricating oil as by partial oxidation and the like appears to be responsible, at least in part, for corrosion of engine parts associated with the combustion chamber and lubricated by means of the same lubricant utilized in the lubrication of the piston rods, pistons, and the like. Also, acidic oxidation products accumulated in lubricating oil appear to exert a catalytic effect in the oxidation of lubricating oil hydrocarbons.

The addition of various types of metal derivatives of organic compounds to lubricating oils is known and practiced to minimize the difficulties already referred to and to improve the properties of these oils in other respects. Thus, various additives which exhibit detergent action in engines are used to minimize deposition of lacquers, resins. carbonaceous materials, and the like, on the engine parts. Basic compounds, such as 'ba'sic'metal compounds, have been. used to provide-"a base reserve to neutralize acidic compounds. Various metal compounds which have been used for such purposes include the metal derivatives of such organic compounds as fatty acids, naphthenic acids, alcohols, phenols, ketones and the like, and corresponding basic or hydroxy salts thereof, instead of the neutral (normal) salt. wherein the metal is a polyvalent metal compound.

It is also known that calcium and other poly- 2 valent metal salts of petroleum or synthetic sulfonic acids have been used as engine oil detergent additio agents, and corresponding basic (hydroxy) s I, ts have been used additionally for their basici as neutralizing agent for acidic bodies in e lubricant, regardless of their source. As a source of reserve alkalinity, the basic (hydroxy) polyvalent metal salts heretofore available have been limited to the usual basic compounds. Thus, in the case of the basic calcium salts of hydrocarbyl sulfonic acids, the neutral salt of which is represented by the formula, (RSOaIaCa, the basic salt is represented by the formula, RSOa.Ca.QH, which is referred to as calcium hydroxy sulfonate. In general the material which has actually been available must be considered, based on analysis, to be a mixture of neutral and basic salts since the free alkalinity of the material is less than the calculated value of the basic salt, RSOa.Ca.0H.

It is an object of the present invention to provide a new class of addition agents for oils which are to be used as crankcase lubricants for internal combustion engines and which exhibit to a high degree the desirable properties of inhibiting the development of corrosivity in the oil, of

improving oxidation stability of the oil, of promoting general enginecleanliness, and reducing ring sticking, piston skirt varnish formation, and the like. Another object is to provide a more highly basic sulfonate salt for use in various oleaginous compositions, including vegetable and animal oils, synthetic oils, mineral oils, etc. Still another object is to provide more highly basic sulfonate salts, of both the oil-soluble and water-soluble types, for various uses, and an improved method for their preparation. Other ob- Jects will appear from the description of the in-- vention.

It has now been found that improved oil compositions ,are obtained by adding to a lubricating 011 small amounts in the order of from about 0.1% .to about 5% S. A. (sulfate ash), of an oil soluble complex polyvalent metal hydroxy salt 3 salt. RSOe-M-(OH) although the less basic monohydroxy salt would be (RSOQMCOH). For polyvalent metals in general the most basic simple hydroxy salt becomes RSO3'M(OH)D wherein b equals the valence of the metal M less one. This new complex may be prepared by treating the neutralor normal polyvalent metal sulfonate, in an inert, anhydrous, solvent medium therefor, with a polyvalent metal alcoholate of the same or a different metal, and subsequently treating the resultant product, from the interaction of the normal sulfonate and the alcoholate, in a water-immiscible solvent for said resultant product, with water under conditions to hydrolyze the metal alcoholate and to produce in said water-immiscible solvent a mixed orcomplex oil-soluble polyvalent metal hydroxy sulfonate.

Various oil-soluble sulfonates may be utilized, including the salts of the well-known petroleum mahogany sulfonic acids, which are usually produced. by the sulfonation of petroleum lubricating oil distillates, preferably rafllnates thereof, from selective solvent refining of the distillate. with concentrated to fuming sulfuric acid, and which mahogany acids remain in the 011 after settling out the acid sludge. These sulfonic acids may be represented by the formula R.SO:.H. wherein R. is usually a naphthenyl, alkylnaphthenyl, alkaryl or a naphthenylaryl radical of a weight such that R.SOa.H generally has a molecular weight of from about 350 to about 500.

To prepare polyvalent metal, particularly alkaline earth metal, mahogany sulfonates, acidtreated oils or extracted (alcoholic) mahogany sulfonic acids may be neutralized directly with an oxide or hydroxide of the desired metal and the mahogany sulfonates recovered. However, it is often more convenient to recover the mahogany acids as the alkali metal sulfonate and then to convert them to the desired salt by double decomposition. Thus, the alkaline earth metal sulfonates may be made by treating an alcoholic solution of sodium sulfonates with an alkaline earth metal salt. Or an oil solution of sodium sulfonate may be emulsified with an aqueous solution of the salt, to form an oil solution of the alkaline earth metal sulfonate and an aqueous solution of inorganic salts.

Instead of the petroleum mahogany acids, synthetic oil-soluble alkylated aromatic sulfonic acids may be utilized in the preparation of the oil-soluble sulfonates of the invention.

other normal or neutral polyvalent metal sulfonates, such as those from the water-soluble green petroleum sulfonates, or simple basic salts thereof. the lower alkanesulfonates (calcium methanesulfonate, magnesium ethanesulfonate, etc), and the like, may be similarly reacted with polyvalent metal alcoholates, followed by hydrolysis, to produce highly basic polyvalent metal sulfonates.

Although sulfonates of the alkaline earth metals, :1. e. calcium, barium and strontium, and the closely related highly basic metal magnesium, are preferred in the practice of the invention, oilsoluble sulfonates of other polyvalent metals, such as zinc, almninum, cobalt, tin, are also useful.

The polyvalent metal alcoholates are preferably those of the alkaline earth metals, of magnesi and zinc and of aluminum, all of which are readily prepared, as is well known, by interaction between the metal and a suitable alcohol, preferably an aliphatic alcohol of from about one to four carbon atoms and which gives a water ethanol, normal and iso-propanol (preferably normal). and the butanols, preferably the primary butanols. normal and iso-butanoL- Higher alcohols, both aiicyclic and acyclic alcohols, may be utilized if a proper selection of reaction condition is made to produce the alcoholate. and also the conditions for hydrolysis of the resulting sulfonate-alcoholate combination are made more vigorous. such as by use of elevated temperatures, under superatmospheric pressure if required.

In accordance with the present invention, a polyvalent metal sulfonate and a polyvalent metal alcoholate are combined and reacted under substantially anhydrous or non-aqueous conditions for a substantial period of time and under conditions to effect the formation of a complex compound. This can be advantageously effected in the case of the oil-soluble sulfonates by intimately contacting aldry (non-aqueous) solution of the sulfonate in a water-immiscible solvent medium therefor with the alcoholate. Suitable waterimmiscible solvents are, for example, mineral oils of lubricating viscosity or some other mixture of hydrocarbons, or an individual hydrocarbon, aromatic or non-aromatic, and mixtures thereof, or a suitable halogenated hydrocarbon. In the case of solvents unsuitable as lubricants or components thereof, it is preferred that they be sufllciently volatile to be readily removed from the product by distillation. Various alcohols alone may be used also as a solvent medium for the reaction. The alcoholate may advantageously be dissolved and/or suspended in a further portion of the alcohol from which the alcoholate is made.

The reaction admixture may be warmed or heated if necessary. Following the interaction of the normal salt and the alcoholate, the water-soluble solvent present, such as alcohol, is removed, as by distillation. Thereafter, the resulting mixture can be filtered or centrifuged to separate any undissolved material, and the homogeneous mixture of addition product dissolved in the water-immiscible solvent medium. or in any other such medium if the first is removed along with the water soluble solvent, is intimately contacted with water or an aqueous solution of a water-soluble salt of the polyvalent metal to hydrolyze the alcoholate portion of the addition product. The hydrolysis is advantageously carried out at a temperature near the boiling point of the solvent,

if that is below the boiling point of water, or with steam, which may or may not be superheated, if the boiling point of the solvent is higher than the temperature of the steam.

For water-soluble and oil-insoluble sulfonates other non-aqueous solvent media may be used. although, under certain conditions, the use of such solvents may be eliminated. The alcohol corresponding to the alcoholate is usually a suitable solvent for such combinations.

For either type of sulfonate the lower molecular weight simple alcohols may be used as solvent media, and the alcoholate may be prepared and reacted with the sulfonate by contacting the alcohol-active metal directly with the alcohol solution of sulfonate. The alcoholate thus formed in situ reacts directly with the sulfonate. The hydrolysis may be effected thereafter either in the presence or absence of the alcohol.

The exact nature of the product resulting from the interaction of the polyvalent metal sulfonate and the polyvalent metal alcoholate, or of the product produced as a; result of the hydrolysis tment of the sulfcnate-alcoholate, are not known at present. It may be a colloidal dispersion ofwalcoh'olate in a mixed a-lcoholate-sulfonate, or

of metal hydroxide in basic metal sulfonate, re-' spectively. However, various physical methods applied to resolve the material were not successful. On the other hand, there is evidence which indicates that some kind of complex compound formation is effected. The resulting oil solution of'the basic material exhibits characteristics of homogeneity, there bing substantially no separation when filtered through biological filters-or when subjected to centrifugation under a force of 10,000 g. The complex basic compound has a free alkalinity or basicity in substantial excess over that of the simple basic salt and may be represented, in general, by the formula (RSOZi)aM(OH)b.M'(OH)m or the equivalent empirical formula (RSOaiaMMKOHMM wherein R is an organic, preferably hydrocarbyl, radical, the sum of "a and b is the valence of the polyvalent metal M,-and n is the valence of the polyvalent metal M, both M and M 'preferably being divalent metals of the alkaline earth metal group and magnesium, which metals together may be termed the strongly basic metals of group II of the periodic classification. For divalent metals the foregoing empirical formula is simplified to RSOa.M=(OH) 1 wherein it is clear that y+1=2x and that the ratio ofthe equiv?" alents of hydroxyl and metal, that is the ratio of 1! to :c (y/x), is greater than 1 (1 is the ratio for the simple basic compound RSO3.M.OH) and less than 2 (2 would be the ratio in the divalent metal hydroxide M(OH)2). It will be seen from this that 11/21: is the ratio'of the number of valences of the metal which are bound to hydroxide groups to the total number of valences (equivalent weights) of the metal present, and that this ratio thus represents the fraction of the metal present that is accountable for as titratable basicity. The ratio of y to a: (y/x), therefore, is numerically exactly twice the fraction of the metal which is accountable for as titratable basicity.

iwithout intending to be bound by any, hypothesis or theory concerning the basic sulfonates of the invention, at least some of the results of analyses may be interpreted to indicate the presence therein of complex compounds of the type represented by'the following formula, taking basic magnesium petroleum sulfonate as-illustrative:

RSO2.OMgOH.Mg(OH)a The Mg(OH)2 quite possibly and probably is bound to the RSOaOMgOH by means of secondary valence forces linking the Mgatom to the accusecounted for by one or more combinationsof the following reactions:

I (R.S0;.0);Mg Mg(OR');-2R.SO;.OMOR' Sulfonste Alcoholate Mixed sulionatealooholete Mixed sulfonate- Alcoholate Com lex compound of mixed alcohoiate su onate-alcoholate and of alcoholate m 11.50;. 0Mg.OR.Mg(OR')| anon-asm monmuon Variations in the free alkalinity of the product are attributable to various proportions of different substances having different basicities, as will be readily understood, the-mixtures being representable by the empirical formula RSOa.Mg=. (OH) 11 Example I Thirty-eight and one-half pounds (0.053 mol) of oil-soluble sodium petronate (Sonnebom 715 base,sulfated residue=9.83%) was dissolved in 15 gallons of benzene in a 25 gallon iron agitator provided with a pressure steam jacket and an air-driven stirrer. To this solution was added 6.1 pounds (0.06 eq., a 10% excess) of magnesium chloride hexahydrate (MgClafiHzQ) dissolved in 2.5 gallons of water. The reaction was heated. with stirring, at C. for 3 hours, then allowed to settle overnight-about 16 hours. After removal of the stratified aqueous phase, the benzene solution was washed twice with 2.5 gallon portions of aqueous-10% MgClafiHzO and twice with water. Benzene was added from time to time to maintain the total volume at 15 gallons. The dissolved water was removed by an azeotropic distillation, adding make-up benzene as required.

Magnesium methylate was prepared by reacting 1.3 pounds (0.053 pound-atom) of magnesium tumings in one quart of methanol in a 22 liter flask provided with an air-stirrer and condenser.

The vigorous reaction that ensued upon mixing the reactants was controlled by an ice bath. Ad-

ditional methanol 'was added until a total of three gallons had been introduced. Toward the end of the reaction, heat was applied to ensure complete reaction and to dissolve as much magnesium methylate as possible in the methanol.

The dispersion (suspension and solution) of magnesium methylate (0.053 mol) in 3 gallons of methanol was added to the anhydrous benzene solution of normal magnesium petronate (petroleum sulfonate, 0.053 eq.=0.0265 mol) in a 50 gallon Pfaudler kettle and the reaction mixture was stirred 'at 45 C. for 1 hour. The methanol was then removed by distillation as an azeotrope accuses The 15 gallons of filtered benzene solution was water-treated batch-wise. Two liters of filtered benzene solution was diluted further with 2 liters of benzene. The solution, heated to near boiling. was placed in a 10 liter separatory funnel wherein it was water-treated. The water treatment was accomplished by adding 800 ml. of warm, aqueous 10% MgClz6HzO and gently swirling the funnel- The aqueous phase quickly settled and was drawn ed; a second similar wash was given. The separated benzene layer was subjected to distillation to remove residual water azeotropically, adding benzene as required After removal of water, benzene was distilled oil, the last trace under reduced pressure (1 hr. at mm. Hg)

There was thus obtained from the 15 gallons, 25 pounds of a dark brown, Viscous material which was a highly basic magnesium petronate.

having the following properties:

Sulfated residue (770 C.) 26.4% by wt. Base neutralization No. (electrometric) 202 mg. KOH/g. Sodium content (expressed as NazSOr) 1.76% by wt. Per cent basicity 1 83% (Empirical formula, RSO:.Mg2.04(OH)c.aa)

Percentage of total metal accountable as titratable basicity.

The foregoing described highly basic magnesium petronate forms an oil solution in mineral lubricating oil which is relatively stable to drastic hydrolysis conditions in the presence of C02 and water, the depletion, as measured by loss in basicity, being only 10% as compared with 22% for a commercially available good grade of an oil-soluble basic calcium petronate. The material exhibits marked oxidation stability and considerable oxidation inhibition characteristics. A blend of the material in a highly refined lubricating mineral oil, in proportions to give a sulfated residue of 1.77%, gave a Dornte time (1500 cc. of oxygen absorption in presence of a crankcase catalyst) of 57 hours and a TBC and 0 time (1500 cc. oxygen) of 106 hours, indicating improved oxidation stability, with a copper-lead bearing weight loss of only 2.1 mg./cm. The corresponding Dornte and TBC and 0 times in the same oil, and even at a slightly higher concentration (S. A.=2.0%) for a commercially available good grade of an oilsoluble basic calcium petronate are hours and 6.6 hours, respectively, while those for neutral calcium petronate are 7 hours and 1 hour, respec tively.

Example I! (an acid (H2804) treated. caustic soda neural-- ized, clay=treated rate from a selective solvent refined neutral distillate cut from a Poso- Coalinga crude mixture) having an SSU viscosity of about 620 at 100 F. and a viscosity index of 54. The oil solution was intimately contacted with 61 grams of MgClz.6H2O dissolved in 500 cc. of water for 2 hours at 00 C. The aqueous and oil phases were allowed to stratify and then separated. The separated oil phase was washed twice with 200 cc. portions of warm 10% MgClz.6l-Iz0 and layered oil. The oil phase was then heated to 150 (3., with stirring, to drive ofi excess water. The resulting oil solution of e neutral agnesium 'petronate contained only 0.011% sodium.

Five-tenths (0.5) or a gram-atom of magnesium was reacted with 500 cc. of methanol in the usual manner (see Example I) and the resulting methanol dispersion 0! magnesium methylate was added to the oil solution of neutral magnesium petronate, and the mixture stirred for 2 hours at 60 C. The temperature was then raised to C. ior one-halt hour and then to C. for 15 minutes to remove traces oi methanol. To the methanol-tree oil solution of the resulting petronate-alcoholate was added 22 cc. (1.2 mols) of water and the intimately contacted mixture was cooked at 95 C. for 1 hour. The excess waterwas removed by heating for 2 hours at 120 C. and then at C. for 20 minutes. Foaming had ceased at the end or the 2-hour heating period at 120 C. If desired antifoaming agents such as alkyl silicones and silicates may be used advantageously to reduce the foaming. The resulting oil solution was diluted with an equal volume of the same highly refined mineral oil and filtered while hot successively through canvas and No. 4 filter paper; no residue was separated on either filter material. The resulting oil solution was slightly cloudy in appearance but various tests indicated the homogeneity of the product additive therein. The following results were obtained upon analysis:

Basicity 36.2 mg. KOH/g. Sulfated ash or residue S. A.) 5.03 Per cent basicity 1 77.0%

(Empirical formula. RSOaJMgmflOHhsc) Example nu An oil concentrate 01 a highly basic oil-soluble calcium petronate (petroleum sulfonate) was pre- .pared by the same method as used in Example 1',

except that calcium chloride was used in place of "magnesium chloride in the preparation of the neutral petronate and calcium and ethanol were used in place of magnesium and methanol for the metal alcoholate preparation and subsequent interactions thereof. Oil solutions or the resulting highly basic calci petronate were also conslderably mproved in characteristics over oil so-- lutions oi both the commercial basic calcium petronate and neutral calcium petronate. The product had a basicity of 84.6 mg. KOH/gram; a sulfated ash of 19.3%, and a per cent basicity, as already defined. of 52%. thus an empirical forsouls of RsO3-C84l.04(OH)1.08. Thus, this product had a per cent basicity in excess of that of the theoretical monohydroxy (monobasic) calcium petroleum sulionate (RSOa.Ca.OH) theoretical value of which is 50% Example IV calci sulionate, having a basicity of 11 mg.

KQlHl/g. material, a suliated ash value of 5%. a

27% metal present as titratable base (empirical formula (RS03 1.46C&.(OH)0.54) was converted into a more highly basic product by dilution with benzene and treating with an ethyl alcohol solution of calcium ethylate, removing the benzene and alcohol, followed by hydrolysis and then drying of the oil product, following the techniques already discussed in the preceding examples. The resulting oil concentrate had a basicity of 39.6 mg. KOH per gram of material and a sulfated ash value of 8.0%; hence, 60% metal accountable as basicity (empirical formula RSOs.Cai.2s.(OH) 1.5.)

This new productwas characterized by its ability to impart much improved properties to lubricating oil compositions as compared with the basic petroleum sulfonate from which it was prepared.

When the oil-soluble highly basic polyvalent metal sulfonates of the invention are used in olea'ginous compositions of lubricating viscosity the proportion generally ranges from about 0.1% by weight, expressed as sulfated residue,'up to saturation, but it is preferred to use from about 0.3%

to about 2.0%.

It will be understood that the basic sulfonates of this invention may be used in lubricating and other oil compositions together with any of the well known compatible additives used to impart oxidation stability, to impart extreme pressure properties, and the like.

The oil-soluble highly basic sulfonates of this invention are also useful in oleaginous compositions other than those which are intended for use as lubricating compositions, as well as in other non-aqueous compositions. Thus, they are valuable as additives for fuel compositions, and other light hydrocarbon compositions, such as rust preventive hydrocarbon compositions, and the like. On account of their surface-active properties, they are also useful in the preparation of oil and water emulsions. They are also useful in spray oils, and the like.

The water-soluble highly basic sulfonates are also useful in the preparation of various oil and water emulsions, such as oil-water spray compositions and the like. They are also useful components of metal-cleaning compositions of a hydrophilic character, particularly those which contain oxygenated organic compounds, such as alcohols, alcohol-ethers, etc.

Thus, the present invention provides a new polyvalent metal basic sulfonate with an alkalinity or basicity at least greater than the theoreti- 'cal value of the corresponding simple basic sulfonate; it provides a new and improved method for the production of basic sulfonates and it provides improved oleaginous compositions containing oil-soluble highly basic sulfonates.

We claim as our invention:

, l. A method for the preparation of an oil-soluble highly basic magnesium petroleum sulfonate which comprises intimately contacting about one mol proportion of an oil-soluble neutral magnesium petroleum sulfonate dissolved in a waterimmiscible organic solvent therefor which is nonreactive with polyvalent metal alcoholates with about two mol proportions of a water-reactive magnesium alcoholate of a lower molecular weight monohydric simple alcohol of 1 to 4 carbon atoms under substantially non-aqueous conditions, subsequently treating the solvent solution of the resulting product with water to hydrolyze the alcoholate to an hydroxide, and separating the solvent and resulting oil-soluble basic magnesium aeeacao of a water reactive divalent metal alcoholate un- 7 l0 petroleum sulfonate dissolved therein from residual water. Y

2. A method for the preparation of an oil-soluble highly basic divalent metal organic sulfonate which comprises intimately contacting about one equivalent weight of an oil-soluble organic sulfonate of a metal selected from the strongly basic metals of group II of the periodic table dissolved in a water-immiscible solvent therefor which is non-reactive with divalent metal alcoholates with at least about two equivalent weights der substantially anhydrous conditions to produce a complex of the sulfonate and alcoholate. treating the resulting solution with water to hydrolyze the alcoholate to an hydroxide, and separating the solvent and dissolved basic sulfonate material from unreacted water.

3. A method for'the preparation of a mineral lubricating oil composition which comprises dispersing about one equivalent weight of an oilsoluble petroleum sulfonate of a metal selected from the strongly basic metals of group II of the periodic table in a refined mineral oil of lubricating viscosity, intimately contacting the resulting dispersion under substantially anhydrous conditions with a dispersion of at least about two equivalent weights of a water-reactive polyvalent vmetal alcoholate ina portion of the corresponding alcohol, said alcohol being a lower molecular weight simple aliphatic alcohol of 1 to 4 carbon atoms, treating the oil solution of the resulting product with water to hydrolyze the alcoholate to hydroxide, removing excess water and any alcohol from the resulting oil solution and thereby recovering a mineral lubricating oil composition containing an oil-soluble basic polyvalent metal sulfonate. i

a. A method for the preparation of an oilsoluble highly basic alkaline earth metal petroleum sulfonate which comprises intimately contacting one mol proportion of an oil-soluble neutral alkaline earth metal petroleum sulfonate dissolved in a water-immiscible organic solvent therefor which is non-reactive with polyvalent metal alcoholates with about two mol proportions oi a water-reactive alkaline earth metal alcoholate of a lower molecular weight monohydric simple alcohol under substantially nonaqueous conditions to produce a complex of the sulfonate and alcoholate, subsequently treating the solvent solution of the resulting product with water sumcient to hydrolyze all of the alcoholate to hydroxide and form free alcohol, and separating the solvent and resulting oil-soluble basic alkaline earth metal petroleum sulfonate in which more than 50% of the alkaline earth metal present is accountable as titratable basicity from residual water and free alcohol.

5. A mineral lubricating oil composition prepared by the method of claim 3. r

6. A mineral lubricating oil composition prepared by the method of claim 3 and wherein the metal of the oil-soluble petroleum sulfonate and of the metal alcoholate is calcium.

'I. A mineral lubricating oil composition prepared by the method of claim 3 and wherein the metal of the oil-soluble petroleum sulfonate and of the metal alcoholate is magnesium.

8. A mineral lubricating oil comprising a major proportion of a mineral lubricating oil and a minor portion, of an oil-soluble highly basic divalent metal petroleum sulfonate of a strongly basic metal of group II of the periodic table. which a free basicity substantially greater ill v than that of the correspon :t monobasic divalent metal petroleum sulionate (.MDH- wherein M is the divalent metal andREO: is petroleum sulfonate) the highly hasic petroleum sulfonate being prepared by intimately contacting about one mol proportion of an oil-soluble petroleum sulfonate of a strongly basic metal of group H oi the periodic table dissolved in a water-= immiscible organic solvent therefor, which is nonreactive with divalent metal alcohoiates, with at least about two mol proportions of en alcoholate of a strongly basic divalent metal of group II of the period table and viewer moieculcr weight monohydric simple alcohol crime 4 carbon a under substantially non-aqueous conditions, subsequently treating the solvent solution oi the re-- sulting product with water to hydrolyze the alcoholate to an hydroxide and recovering the resulting oil-soluble highly basic .divaient metal petroleum sulfonate from residual water and alcohol. 9. A lubricating composition according to claim 8, wherein the highly basic petroleum sulronate is a magnesium petroleum sulfonate which has the baslcity 0!. a substance represented by the formula RSOa.Mg2(OH) 3.

10. A lubricating composition according to sesame l2 3, wherein the highly basic petroleum sulionai'e has the basicity of a basic divalent metal 4 nnrnnnncns omen The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,361,804 Wilson Oct. 31,1944 2,402,325 Griesinger June 18, 1940 2,413,311 Cohen Dec. 31. 1946 2,444,970 Zimmer July 13; 1948 2,467,176 Zimmer Apr. 12, 1949 2,485,861 Campbell Oct. 25, 1949 2,501,732 Mertes Mar. 28. 1950

Claims (1)

1. 8. A MINERAL LUBRICATING OIL COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL AND A MINOR PORTION OF AN OIL-SOLUBLE HIGHLY BASIC DIVALENT METAL PETROLEUM SULFONATE OF A STRONGLY BASIC METAL OF GROUP II OF THE PERIODIC TABLE, WHICH A FREE BASICITY SUBSTANTIALLY GREATER THAN THAT OF THE CORRESPONDING MONOBASIC DIVALENT METAL PETROLEUM SULFONATE (RSO3M.OHWHEREIN M IS THE DIVALENT METAL AND RSO3 IS PETROLEUM SULFONATE), THE HIGHLY BASIC PETROLEUM SULFONATE BEING PREPARED BY INTIMATELY CONTACTING ABOUT ONE MOL PROPORTION OF AN OIL-SOLUBLE PETROLEUM SULFONATE OF A STRONGLY BASIC METAL OF GROUP II OF THE PERIODIC TABLE DISSOLVED IN A WATERIMMISCIBLE ORGANIC SOLVENT THEREFOR, WHICH IS NONREACTIVE WITH DIVALENT METAL ALCHOLATES, WITH AT LEAST ABOUT TWO MOL PROPORTIONS OF AN ALCOHOLATE OF A STRONGLY BASIC DIVALENT METAL OF GROUP II OF THE PERIODIC TABLE AND A LOWER MOLECULAR WEIGHT MENOHYDRIC SIMPLE ALCOHOL OF 1 TO 4 CARBON ATOMS UNDER SUBSTANTIALLY NON-AQUEOUS CONDITIONS, SUBSEQUENTLY TREATING THE SOLVENT SOLUTION OF THE RESULTING PRODUCT WITH WATER TO HYDROLYZE THE ALCOHOLATE TO AN HYDROXIDE AND RECOVERING THE RESULTING OIL-SOLUBLE HIGHLY BASIC DIVALENT METAL PETROLEUM SULFONATE FROM RESIDUAL WATER AND ALCOHOL.