US2499710A - Anticorrosive lubricating oil and a process of fractionating alkali and alkaline earth metal petroleum sulfonates - Google Patents

Description

Patented Mar. 7, 1950 ANTICORROSIVE LUBRICATING OIL AND A PROCESS OF FRACTIONATING ALKALI AND ALKALINE EARTH METAL PETRO- LEUM SULFONATES Chester E. Wilson, San Pedro, Calif., assignor to Union Oil Company of California, Los Angelel, Calif., a corporation of California No Drawing. Application April 6, 1945, Serial No. 587.021

17 Claims.

This invention relates to a method of treating suifonated mineral or fatty oils, which sulfonates find wide application in the preparation of anticorrosion agents. More particularly the invention relates to new and improved rust preventive oils containing sulfonated oils, treated by the method as hereinafter described.

When metals are stored, especially in the form of finished articles, composed in whole or in part of metals. particular care is required to protect the surfaces from corrosion. Several types of rust preventive'compositions have been developed with the express purposes of preventing this corrosion during storage. One such type of rust preventive composition, which usually contains a large proportion of petrolatum, deposits a waxy or unctuous film on the metal surfaces by dipping the article in the molten rust preventive. Another type, which contains compounds dissolved in a volatile solvent, leaves an impervious film on the sprayed or dipped article after evaporation of the solvent. The protective coating from the second type may result by simple evaporation of the solvent or by oxidation and drying of the compounds in the rust preventive composition. Such compositions may contain sulfonated mineral oils as anticorrosion agents.

In addition to the above types of rust preventive compositions are the equally important ones of anticorrosive lubricating oils and greases employed in the lubrication and storage of machinery, engines, parts, tools, and the like. These compositions have the property, in addition to lubrication, of inhibiting the corrosion of metal surfaces of such equipment. These anticorrosive lubricating oils generally contain a mineral oil and from 1% to and more often in the range of from 2% to 5% of metal soap of a petroleum sulfonic acid. In conjunction with these constituents various additives are often employed such as other anticorrosive agents for example degras or lanolin, pourpoint depressants comprising for example Friedel-Crafts condensation products of chlorinated waxes and aromatics, antioxidants such as the thiophosphates and the phenol sulfide soaps or salts, viscosity index improvers as for example polyisobutylene and the polymerized higher esters of methyl acrylic acid, and foam suppressors or inhibitors. A grease containing an anticorrosion agent would be comprised of essentially the above ingredients with the addition thereto of a metal soapof a fatty acid as the thickening agent.

Anticorrosive lubricating oils and greases of this class find application both in the lubrication of metal bearings and as a coating to prevent rusting of metal articles during storage. In this latter case these lubricating oils have an advantage over the coating compounds as above described in that it is not necessary that they be removed from the metal parts prior to usage. Such anticorrosive lubricating oils and greases must fulfill not only the qualifications of a good lubricant: that is of a conventional lubricant not possessing anticorrosive properties such as stability towards oxidation at high temperatures, resistance to decomposition at high temperatures and resistance to separation at low temperatures, but further they must exhibit anticorrosive properties during exposure to h gh relative humidity, to adverse weather conditions, and to marine atmospheres.

High humidity may be encountered by machinery or other metal parts by exposure to atmospheric conditions of high humidity which occur particularly in the tropics. It is a particular function of an anticorrosion agent therefore to resist .this high humidity inasmuch as the rate of rusting appears to be a function of the degree of humidity. For such purposes either of the two types of anticorrosion agents described may be employed. However, high humidity is also encountered in internal combustion engines when the engines are in the process of cooling, the relative humidity increasing rapidly with a decrease in temperature. For protection from corrosion under such conditions the anticorrosion lubricants must be employed inasmuch as they must not only protect the vital parts from rusting under these conditions of induced high humidity but they must lubricate the contactin surfaces when the motor is in operation.

It is a particular object of my invention to provide anticorrosion lubricants which have bet-.

ter resistance to conditions of high humidity or actual condensation, which may occur under such conditions, and further to provide a process whereby such improved anticorrosion lubricants may be prepared.

It is a more particular object of my invention to prepare anticorrosion lubricants having improved resistance to humidity by treating the sulfonate soaps employed as the anticorrosion agents in such lubricants by a simple and economical manner.

Another object of the invention is to provide a simple and economical process for extracting the metal soaps and particularly the alkali or alkaline earth metal soaps of the petroleum sulfonates in such a manner as to produce a railinate which when incorporated in an anticorrosion lubricant is capable of imparting thereto improved resistance to humidity over that which would result if the untreated sulfonate were employed.

Other objects and advantages of my invention will become apparent to those skilled in th art as the description thereof proceeds.

I have found that the commercially available 3 organic sulionates, that is the metal soaps .oi' the organic sulfonic acids, in particular, the petroleum sulfonic acids. are inadequate for the preparation of anticorrosive lubricating oils and greases. Their inadequacy is witnessed in the failure of rust preventive compounds employing these metal soaps to pass specified corrosion tests. I have found that this diinculty can be remedied by treating the suli'onates, which term will hereinaiter be employed to designate the metal soaps of the sulionic acids, with a solid adsorbent which has the effect or adsorbing a certain proportion of the suli'onate. The composition of that part of the sulionate which is adsorbed is as yet unknown but the raillnate in this adsorption when included in a suitable lubricating oil base will give a product which passes all the tests required for such anticorrosive lubricating oils.

As adsorbents for this purification I have found to be effective such materials as the clays including bentonite, kaolin, kaolinite, ball clays and the like, the aluminas, either naturally occurring or synthetic such as bauxites, synthetic activated alumina and the like, synthetic aluminum silicates, silica gel, magnesia, other metal oxides or hydrous oxides, natural adsorbents such as fuller's earth, and the like, and carbon adsorbents such as charcoal, coke, coal and the like. or this group I have found the clays, and particularly the hentonitic clays of montmorillonite structure are the best adsorbents from a chemical as well as a practical standpoint.

I may efiect the treatment of the sulfonates with these adsorbents in any desired manner such as batchwise contact, percolation through a bed of such adsorbent, countercurrent extraction and the like. In this regard I have observed that during the percolation ofthe suli'onates through a bed of adsorbent such as a bentonitic clay, a stratification occurs suggesting the possibility of a chromotographic separation. However, such separation of the various strata is not an essential element of my process inasmuch as I have determined that there is an optimum amount of sulfonate to be removed from the original feed to give a satisfactory product and a separation of the removed sulfonate into various constituents will have no effect on the rafllnate from the extraction.

In most cases it is desired to employ a solvent in conjunction with the sulfonate to be treated to facilitate the treating operation. The commercially available sulfonates generally consist of solutions of the sulfonate in a mineral oil, the sulfonate being present to the extent of from 50% to 70%. in the solution, which solution of sulfonate in mineral oil will hereinafter be referred to as sulfonate solution.

This sulfonate solution may if desired be contacted, as such, with the desired adsorbent but I have found that the treatment is more effective if the sulfonate solution is further diluted with a non-polar solvent such as a light hydrocarbon or the oil to be used in the resultant antlcorrosion lubricating oil. This latter type of dilution probably represents the best method of procedure inasmuch as there is no necessity of separating the treated sulfonate from the solvent diluent prior to its incorporation as the anticorrosion agent in a lubricating oil or ease.

Further, I have found that the extraction is more eifective if carried out at an elevated temperature such as from about 200 F. to about 350 1''. This temperature appears to be a function of the solvent employed, that is with a lighter solvent a lower temperature will eifect the same degree of extraction as a higher temperature with a heavier solvent. On this basis it would appear that the temperature plays an important part not only in activating the adsorption but in relation to the eventual product as a result of a decrease in the viscosity of the solution to be treated incurred by an increase in temperature. I do not wish to be limited, however, to the temperature range of 200' I". to 350' l". inasmuch as temperatures below and above this range are also eifective but I shall avoid excessive temperatures, such as above 450 E, which cause a detrimental change in the characteristics of the sulionate. As shown in Example 1 hereinbelow the extraction may be satisfactorily carried out at temperatures as low as 100 1''.

After the extraction the adsorbent may be reactivated and the extracted sulionate may be recovered in any desired manner. I have found that this may be accomplished simply and effectively by extracting the adsorbent with a polar solvent to selectively displace the sulfonate from the clay. The adsc bent, preferably in the presence of the next batch of sulfonate to be purified, is subsequently heated to a temperature sufilcient to remove the solvent by evaporation, the solvent vapors being condensed and recovered to be re-employed. and the solvent extracted suifonate is heated in a similar manner to remove the solvent therefrom. This extract if completely freed of the polar reactivating solvent will be in the form of a comparatively pure powdered sulfonate. For this reason it may be desirable to dilute the solvent-'sulfonate mixture with a mineral oil prior to evaporating the solvent therefrom. For this reactivation I may employ any polar solvent such as the low molecular weight alcohols and ketones or other low molecular weight compounds containing polar groups. The reactivation is simplified by employing a low boiling polar solvent in that heat requirements for its recovery from the adsorbent and extract are considerably less than if high boiling solvents are employed. The preferred solvent for the reactivation of the adsorbent is isopropyl alcohol because of the resulting effective displacement of the sulfonate from the adsorbent. ease of handling, and its low cost. It is,however, to be understood that I do not intend to be limited to the use of this one solvent as I have found many other low molecular weight polar solvents particularly the alcohols and ketones to be eifective.

Generally the petroleum sulfonates are prepared by treating a mineral oil fraction in the lubricating oil range in successive stages with sulfuric acid. These lubricating oil fractions to be sulfonated vary widely in such characteristics as parafiinicity, viscosity index and the like. The acid concentration is increased in each successive stage of the sulfonation until fuming acid is employed in the later stages to give the mahogany acids. These mahogany acids are neutralized with .caustic to give the mahogany soaps or sulfonates and are extracted from the oil with aqueous alcoholic solutions. A more complete description of the general process is difiicult due to the many modifications that may be employed. A second method of sulfonation consists in treating the mineral oil with sulfur trioxide which treatment may be at high or low temperatures and with or without other solvents being present. In any case, however, the sulfonated products usually consist of the mahogany sulfonic acids and green acids.

, version of the latter to the metal sulfonates for use as anticorrosion agents. Herein lies a possible explanation for the effectiveness of the puriflcation of the sulfonates according to my invention. It is possible that green acids remain in the majority of mahogany sulfonic acids causing the failure of the resulting anticorrosion agents, and thatthe metal soaps of these green acids are removed in the adsorption process as herein described.' It is to be understood that this is only a possible explanation of the beneficial effect realized in the adsorption process and I do not wish to be limited thereby.

In the extraction of these sulfonates I have found that it is desirable to eifect the removal of from 15% to 30% by weight of the sulfonate in order to obtain an effective anticorrosion agent. which upon compounding with a suitable lubricating oil will pass the necessary specifications. In this regard I have found that the improvement in the oil with respect to resistance to humidity and condensation is a function of the per cent sulfonate extracted up to a point, after which no further improvement can be detected by presently known test methods. That is if I remove of the sulfonate in the extraction process an improvement in the resultant anticorrosion lubricant results which, however, is insumcient to meet the necessary requirements, and for this reason I have established the desired range of sulfonate removal of about 15% to 30%, a removal in this range being sufiicient to give a product of the necessary qualifications. However, it is to be understood that more stringent purification may be applied, that is an extraction in excess of 30% may be accomplished without departing from the scope of this invention inasmuch as this range was merely established as a critical range below which the extraction was beneficial but insufficient to meet presently employed test methods. Thus if requirements for anticorrosion lubricants should become more rigorous and test methods are developed or employed which reveal greater differentials in such anticorrosion lubricants it may be desired to increase the degree of extraction to a figure about 30%.

On the other hand, with some, particular petroleum sulfonates the concentration of undesirable components may be relatively low, and it will be necessary to remove a correspondingly small proportion by the purification procedure.

Further, I have found that it is not necessary to replace this 15% to 30% of removed petroleum sulfonate with additional purified sulfonate in order to produce an excellent anticorrosive product. Thus an anticorrosive lubricant, requiring for example 3.25% of a petroleum sulfonate may find use in certain applications although it does not meet the rigid requirements as hereinbefore referred to, and if I treat the sulfonate according to the process of this invention removing, for example, 30% thereof a subsequent oil containing only-the remaining 70% or 2.28% sulfonate will be more efiective than the original composition. Thus as I remove a given percentage of sulfonate by extraction the concentration required in an anticorrosive lubricating oil is at least correspondingly reduced and in some cases is reduced below this proportional amount. Further than this I have found that the extracted sulfonate after removal from the for a period of at least 150 hours.

adsorbent by any process, as for example the one hereinbefore described, may be utilized in applications other than anticorrosive agents such as for example soluble cutting oils and the like. In the following examples the humidity test method as set up in the Government Specification AN-VV-C-576a is employed to ascertain the improvements in the anticorrosion lubricants containing the sulfonates treated according to my invention.

Standard test procedure according to this specification requires that two 2-inch by 4-inch by 5-inch sand-blasted panels of steel shall be dipped in a suitable sample of the anticorroslve oil so as to completely submerge all surfaces. The panels are then suspended vertically by glass hooks for at least four hours in an atmosphere maintained at a relative humidity of from 50% to 55% and at a temperature of 25 Cl -3 C. At the end of this period the panels are suspended vertically in a humidity cabinet maintained at a relative humidity of to at a temperature of 49 C. :3 C.

The conditioned air is passed through the cabinet at a rate of '7 feet to 9 feet per hour. At the expiration of the test the panels are removed, cleaned with naphtha and examined, and if these panels show any evidence of corrosion, pitting or other attack involving either surface within A; inch from any edge they are considered as having failed the test.

There is still speculation in regard to the mechanism of rusting. It is held by some that rusting does not occur until the humidity at the surface of the metal is 100% that is until actual condensation occurs. Others however maintain that the rusting occurs as a result of the humidity of the atmosphere, as distinguished from actual condensation on the metal, and that higher humidities accelerate the rusting. This test is, however, designed to provide both of these conditions and it is apparent that an improvement in the resistance of an oil to either is an improvement in resistance to both.

Example I In one example of the effectiveness of th s purification process to improve the resistance of anticorrosion lubricants to humidity and condensation an anticorrosive compound was prepared comprising 1S% of a 60% solution of sodium soap of petroleum sulfonic acid, 10.5% of a 20% solution of an antioxidant, in this case the calcium salt 'of amylphenol sulfide, and 76.5% of a SAE 40 lubricating oil. This composition was diluted with three parts of Navy Symbol 1120 oil and then subjected to the test as above described. Navy Symbol 1120 oil as herein referred to consists of a paraflinic mineral oil conforming to certain Navy specifications but generally defined as having a viscosity of seconds at 210 F. by the Saybolt Universal method of viscosity determination and a minimum viscosity index of 95. This initial composition containlng the untreated sulfonates failed the above test in that considerable corrosion of the test panels resulted.

A second composition was prepared in which one part of the'same sodium soap of petroleum sulfonic acids was treated in the presence of four parts of light hydrocarbon with one part of bentonitic clay at a temperature of 100 F. removing thereby 17% of the sulfonate as evidenced by a sulfate ash of 8.3% after removal of the light hydrocarbon solvent as compared to a sulfate ash of 10% in the original material. This treated sulfonate comprising after treatment and removal of light hydrocarbon solvent 49.8% sulfonate in mineral oil was incorporated in a lubricating oil as follows: 15.7% of the treated sulfonate solution, 10.5% of a solution of the calcium salt of amylphenol sulfide, 73.8 of an SAE 40 lubricating oil. This mixture having the same composition as that in the first part of this example by virtue of adjusted proportions compensating for the change in composition of the sulfonate solutions was again diluted with three parts of Nav Symbol 1120 oil and subjected to the above described test with no evidence of corrosion on the test panels at the termination thereof, indicating the improvement of the final oil in regards to its resistance to high humidity brought about by the treatment of the sulfonate.

Example II Another sample of a mineral oil solution of sodium soap of a petroleum sulfonic acid was clay treated at 300 F. in the presence of 4 parts of an SAE 40 lubricating oil to reduce the sulfate ash content of the mixture from 2.0% to 1.35% or a reduction of 32.5%, and 65 parts of this mixture was mixed with 10.5 parts of a 20% solution of the calcium salt of amylphenol sulfide and 24.5 parts of the same SAE 40 lubricating oil as employed as a diluent in the extraction resulting in a composition containing 5.25 of sulfonate,-on an oil free basis, 5.2% oil from the original sulfonate solution, 10.5% of the amylphenol sulfide solution and 79.05% of SAE 40 lubricating oil.

A second composition was prepared using 13% of untreated sulfonate solution, equivalent to 7.8% of sulfonate on an oil free basis, 10.5% of the 20% solution of calcium salt of amylphenol sulfide and 76.5% of the SAE 40 lubricating oil, as in the above example, and these two compositions were diluted with.3 parts Navy Symbol 1120 lubricating oil and tested according to the specifled procedure. In this test the oil containing the treated sulfonate passed without sign of corrosion, while the one containing untreated sulfonate failed because of corrosion of th test panels. It should be noted that the oil containing treated sulfonate passed the test in spite of the presence of only 68% as much sulfonate as present in the second composition which failed the test. This type of test has been repeated a number of times with thoroughly consistent results, that is those compositions containing a sulfonate fromwhich has been removed at least 15% of the sulfonate by extraction with the solid adsorbent have resulted in compositions which universally pass the above test, while those compositions containing an untreated sulfonate universally fail the above test.

Although my preferred method of treating thesepetroleum sulfonate soaps to obtain a fraction thereof which is superior to the original sulfonatein imparting properties of resistance to corrosion under conditions of high humidity is by contacting these alkali and alkaline earth metal soaps of the petroleum sulfonic acids with a solid adsorbent as hereinbefore described, I have also found that the sulfonates may be extracted with other extractive agents comprising organic solvents to accomplish much the same effect. As solvents for this extraction I may employ the various alcohols and ketones and particularly the low molecular weight alcohols and ketones such as isopropyl alcohol, ethyl alcohol, butyl alcohol, methyl ethyl ketone, methyl isopropyl ketone and the like or mixtures of these. These solvents may be employed in any known type of solvent extraction process such as countercurrent, concurrent, batchwise, continuous or the like to separate the sulfonate into a more desirable and a less desirable traction on the basis of the humidity resistance of the anticorrosion lubricants in which they may be employed.

The foregoing description and examples of the invention are not to be taken as limiting since many variations may be made by those skilled in the art without departing from the spirit or scope of the following claims.

I claim:

1. A process for treating soaps selected from the class consisting of the alkali and alkaline earth metal soaps of sulfonated mineral oils to improve their resistance to humidity which comprises contacting a mineral oil solution of said soaps at a temperature between about F. and about 450 F. with a sufiicient amount of a solid adsorbent to extract between about 5% and 30% of said soaps therein having a comparatively lower resistance to humidity.

2. A process for treating the alkali metal soaps of sulfonated mineral oils to improve their resistance to humidity which comprises contacting a mineral oil solution of said soaps at a temperature between about 100 F. and about 450 F. with a suflicient amount of a solid adsorbent to extract between about 5% and 30% of said soaps therein having a comparatively lower resistance to humidity.

3. A process for treating the sodium soaps of petroleum sulfonic acids to improve their resistance to humidity which comprises contacting a mineral oil solution of said metal soaps at a temperature between about 100 F. and about 450 F. with a suflicient amount of a solid adsorbent to extract between about 5% and 30% of said soap therein having a comparatively lower resistance to humidity.

4. A process for treating one of a group consisting of the alkali and alkaline earth metal soaps of petroleum sulfonic acids to improve their resistance to humidity which comprises contacting a mineral oil solution of said metal soaps at a temperature between about 100 F. and about 450 F. with a sufllcient amount of clay to extract between about 5% and 30% of said soaps therein having a comparatively lower resistance to humidity;

5. A process for the separation of soaps selected from the class consisting of the alkali and alkaline earth metal soaps of sulfonated mineral oils into a fraction having a high resistance to humidity and a fraction having relatively lower resistance to humidity than the original sulfonate which comprises contacting a mineral oil solution of said soaps with a quantity of a solid adsorbent to remove at least from about 5 to about 30% of said soaps at a temperature between about 100 F. and about 450 F., separating the rafilnate or improved fraction from said adsorbent, washing said adsorbent with a polar solvent to recover the soap extract and heating said sulfonated oil extractto recover the solvent therefrom.

6. A process for the separation of the alkali metal soaps of a petroleum sulfonic acid into a fraction having a high resistance to humidity and a fraction having relatively lower resistance to humidity than the original sulfonate which comprises contacting a mineral oil solution or said petroleum sulfonate with a sufllcient quantity of a solid adsorbent to remove at least from about to about 30% 01' said petroleum sulfonate soaps at a temperature between about 100 F. and about 450 F. separating the rafllnate or improved fraction from said adsorbent, washing said adsorbent with a polar solvent to recover the petroleum sulfonate extract and heating said petroleum sulfonate extract to recover the solvent therefrom.

7. A process for the separation of an alkali metal soap of a petroleum suli'onic acid into a fraction having a high resistance to humidity and a fraction having a relatively lower resistance to humidity than the original sulfonate which comprises contacting a mineral oil solution of said metal soap of a petroleum sulfonic acid at a temperature between about 100 F. and about 450 F. with a sumcient quantity of clay to effect the removal 01' at least from about 15% to about 30% of said metal soap oi the petroleum sulfonic acids, and separating the ramnate or improved fraction from the resulting adsorbent.

8. A process for the separation of an alkali metal soap of a petroleum sulfonic acid into a fraction having a high resistance to humidity and a fraction having a relatively lower resistance to humidity than the original suli'onate which comprises contacting a mineral oil solution of said metal soap of a petroleum sulionic acid at a temperature between about 100 F. and about 450 F. with a sufllcient quantity oi! silica gel to eil'ect the removal of at least from about 15% to about 30% of said metalsoap oi the petroleum suli'onic acid, and separating the raiilnate or improved fraction from the resulting adsorbent.

9. A process for the separation 01' an alkali metal soap of a petroleum suli'onic acid into a fraction having a high resistance to humidity and a fraction having a relatively lower resistance to humidity than the original suli'onate which comprises contacting a mineral oil solution of said metal soap of a petroleum sulionic acid at a term perature between about 100 F. and about 450 F. with a suilicient quantity of charcoal to eilect the removal of at leastirom about 15% to about 30% of said metal soap of the petroleum sulfonic acid, and separating the rafllnate or improved fraction from said adsorbent.

10. A process for the separation of the alkali metal soaps of petroleum sulfonic acid into a fraction having a high resistance to humidity and a fraction having a relatively lower resistance to humidity than the original sulfonate which comprises contacting a mineral oil solution of said petroleum suli'onate with a sufllcient quantity of a solid adsorbent to remove at least from about 15% to about 30% of said petroleum sulionate soap at a temperature between about 100 F. and about 450 F., separating the ramnate or improved fraction from said adsorbent, washing said adsorbent with isopropyl alcohol to recover the petroleum sultonate extract and heating said petroleum sulfonate extract to recover the solvent therefrom.

11. A process for the separation of the alkali metal soaps oi petroleum sulfonic acid into a fraction having a high resistance to humidity and a fraction having a relatively lower resistance to humidity than the original sulionate which comprises contacting a mineral oil solution oi said petroleum sulionate with a sumcient quantity oi a clay adsorbent to remove at least from about 15% to about 30% of said petroleum sulfonate soap at a temperature between about 100 F. and about 450 F., separating the rafllnate or improved fraction from said adsorbent, washing said adsorbent with a polar solvent to recover the petroleum sulfonate extract and heating said petroleum sulfonate extract to recover the solvent therefrom.

12. An anticorrosive lubricating oil having high resistance to humidity consisting essentially of a lubricating oil and soaps selected from the class consisting of the alkali and alkaline earth metal soaps of petroleum sulfonic acids, which petroleum sulfonate soap is obtained as the raffinate from the treatment of a mineral oil solution of the corresponding untreated soap of a petroleum sulfonic acid at a temperature between about 100 F. and about 450 F. with a substantial amount of a solid adsorbent so as to extract between about 5% and 30% of the soaps therein having a comparatively lower resistance to humidity.

13. An anticorrosive lubricating oil having high resistance to humidity consisting essentially of a lubricating oil and an alkali metal soap of a petroleum sulfonic acid, which petroleum sulfonate soap is obtained as the raflinate from the treatment of a mineral oil solution of an alkali metal soap of a petroleum sulfonic acid at a temperature between about 100 F. and about 450 F. with a substantial amount of a solid adsorbent so as to extract between about 5% and 30% of the soaps therein having a comparatively lower resistance to humidity.

14. An anticorrosive lubricating oil having high resistance to humidity consisting essentially of a lubricating oil and a sodium soap of a petroleum sulionic acid, which petroleum sulionate soap is obtained as the raflinate from the treatment of a mineral oil solution of a sodium soap oi a petroleum sulfonic acid with a quantity of a solid adsorbent at a temperature between about 100 F. and about 450 F. so as to extract at least from about 15% to about 30% of said soap.

15. A process according to claim 4 in which the contacting temperature is between about 200 F. and about 350 F.

16. A process according to claim 4 in which the metal soaps in solution in mineral oil are diluted with a light hydrocarbon traction and the resulting solution is contacted with clay.

17. Ananti-corrosive lubricating 011 according to claim 12 in which said mineral oil solution of .untreated soap is diluted with a light hydrocarbon fraction and the resulting solution contacted with solid adsorbent.

CHESTER E. WILSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Barbour Feb. 26, 1946

Claims (1)

12. AN ANTICORROSIVE LUBRICATING OIL HAVING HIGH RESISTANCE TO HUMIDITY CONSISTING ESSENTIALLY OF A LUBRICATING OIL AND SOAPS SELECTED FROM THE CLASS CONSISTING OF THE ALKALI AND ALKALINE EARTH METAL SOAPS OF PETROLEUM SULFONIC ACIDS, WHICH PETROLEUM SULFONATE SOAP IS OBTAINED AS THE RAFFINATE FROM THE TREATMENT OF A MATERIAL OIL SOLUTION OF THE CORRESPONDING UNTREATED SOAP OF A PETROLEUM SULFONIC ACID AT A TEMPERATURE BETWEEN ABOUT 100*F. AND ABOUT 450*F. WITH A SUBSTANTIAL AMOUNT OF A SOLID ADSORBENT SO AS TO EXTRACT BETWEEN ABOUT 5% AND 30% OF THE SOAPS THEREIN HAVING A COMPARATIVELY LOWER RESISTANCE TO HUMIDITY.