US2361804A - Lubricating composition - Google Patents

Description

Patented Oct. 31, 1944 2,361,804 LUBBICATING courosmon Chester E. Wilson, San Pedro, GaliL, assignor to Union Oil Company of California, Los Angeles, Calii., a corporation of California No Drawing.

Application February 18, 1941, Serial No. 319,439

28 Claims. (01. 252-33) This invention relates to mineral lubricating oils which have been modified by the addition of constituents to impart to them special characteristics especially adapting them to severe serv..

ice uses such as are encountered in Diesel engines, high output aviation engines and the like.

This application'is a continuation-in-part of my copending applications, Serial No. 277,677, filed June 6, 1989, Serial No. 305,496 filed November 21, 1939, Serial No. 345,844 filed July 16,1940, now issued as Patent No. 2,280,419 of April 21, 1942, and Serial No. 362,009 filed October 16, 1940.

In Diesel and similar engines the high temperatures developed in the cylinders tend to act upon lubricating oils to cause the deposition of resinous and varnish-like products on the pistons and elsewhereto produce lacquer-like coatings 3% of oil-soluble metal salts of the weakly acidic non-carboxylic organic acids, said salts being capable of reacting with acidic corrosive materials formed or present in the oil during use to form metal salts of such corrosion products and liberate free non-carboxylic acids which are sufilcient- 1y weak to be non-corrosive to hearings or the and carbonaceous materials which tend to cause ring and valve sticking and interfere with engine operation. Furthermore, iuel residues from incomplete combustion of fuel contribute to the deposition of lacquer-like and carbonaceous materials in the engine. Previously in aneflort to overcome these difllculties various types of metal soaps of fatty acids and the like have been introduced into the lubricating oil, and they have exhibited a detergent effect in that they have acted to prevent such depositions. However, in general, it has been observed that in those engines fitted with certain types 01. bearings, such as cadmium-silver or copper-lead bearings, the use of such fatty acid soap-compounded oils has often given rise to bearing corrosion, such corrosion apparently being due to the formation in the oil of corrosive materials of acidic character. The formation of these corrosive materials may even be catalyzed by the presence of such soaps in the oil. Also, some of the metal soaps added as detergents have required the use of free fatty acid and the like to act as a common solvent to promote solutionsof the soaps in the oil, and the presence of such free acidity has possibly contributed to the corrosion of alloy bearings 01 the type mentioned above.

Primarily, the object of this invention is to produce for such severe service conditions as are encountered in Diesel engines, lubricating oils which will be non-corrosive to corrosion-sensitive bearings of the copper-lead and cadmium-silver type and which will also avoid the deposition of lacquer and varnish-like materials upon pistons and overcome carbon deposition behind the rings.

The present invention in one aspect resides in mineral lubricating oils containing small amounts in the order of about 0.5% or 0.75% up to 2% or copper-lead and cadmium-silver alloy p Itls possible that the metal salts of weak non-carbonylic organic acids within the scope of this invention which are considered as "anti-corrosion" agents also act as anti-oxidants tending to prevent thei'ormation oi. corrosive acidity.

The invention further resides in lubricating oils containing correspondingly small amounts of such oil-soluble anti-corrosion agents in combination with correspondingly small amounts of other oil-soluble soaps or salts which act as "detergen agents. The detergent type soaps include high molecular weight oil-soluble soaps of carboxylic acids containing more than about 12 carbon atoms per molecule; they also include oilsoluble metal suli'onates' herein described which are especially valuable in highly paraillnic (high viscosity index) oils.

The invention also resides in the employment of small amounts or water in the oil composition sufllcient to insure activation of the anti-corrosion agent, either with or without respect to the presence of a detergent soap, wherein the water content however is not suilicient to produce gelling tendencies or interfere with the compatibility of the agents with the oil or with each other. Such a water content in the final product will be within a range of around two-thousandths per cent (0.002%) to two-hundredths' per cent (0.02%) or possibly a little wider.

However the invention also includes, especially for some combinations containing detergent soaps, the use of somewhat larger quantities or water to activate the detergent soap and render it more efficient as a detergent. In this connection the water content appears to run between about 0.05% (or perhaps as low as about 0.01% or 0.02%) and about 0.25%. In general the smaller proportions are used in oils containing soaps which tend to gel or cloud readily. Other soaps such as the sulionates accept the larger proportions and can accept even more, although the additional amounts of water do not appear to ofler any additional advantage. These larger proportions of water, of course, also activate the anti-corrosion agents.

- In some instances it is desirable to have in the final product-a relatively smaller quantity oi. the

initial acidic starting material from which the salt of the anti-corrosion agent is prepared, and the invention further resides in modified oils of this invention containing also relatively small proportions of these free acidic materials as solubilizers or compatibility-promotion constituents.

The term soap, which is sometimes herein used to indicate the salts of this invention, indicates salts of high molecular weight materials possessing at least ten carbon atoms per molecule so as to impart good dispersibility or solubility in the mineral lubricating oil when in the form of salts of those metals whose salts are sufllciently oil-dispersible or "soluble" as here required.

By the term detergent" is meant the property of removing, or materially retarding the accumulation of resinous, varnish-like and carbonaceous materials which otherwise tend to deposit upon or around piston rings or valve stems and cause sticking thereof. The term "sulfonates" means those oil-soluble metal soaps which are produced from sulfonic acids obtained from petroleum and known as "mahogany acids. and have high detergent value, such as sodium, potassium, calcium, barium, strontium and magnesium salts, and some heavy metal salts such as copper, zinc, aluminum, lead, nickel, cobalt, manganese, chromium, tin and iron, especially the alkaline earth metal soaps.

By the term weakly acidic non-carboxylic organic acids it is meant to include those noncarboxylic acidic materials having ionization constants of about l 10-" or less, and preferably in the range of about lxlto 1 10 However, in some instances it may be acceptable to use materials whose ionization constant is as high as 1x10 It may also be possible, at least for some uses, to employ those weakly acidic materials having ionization constants up to about 5 10, but in no case so far as now known can about 5 1O- be exceeded; this limit safely excludes the carboxylic acids. Such compounds comprise the phenols, thiophenols, other enols, oximes, sulfonamides having an acidic hydrogen atom, and the like, detailed hereinafter.

Although any of the oil-soluble metal salts of the above mentioned groups of compounds will be effective in preventing the corrosion of bearings such as those of cadmium-silver and copper-lead alloys and will tend to prevent the deposition of carbonaceous materials in the engine, I particularly prefer to employ the oil-soluble metal salts of phenols.

By the term phenols is meant to include not only the hydroxy aromatic ring compounds in which an hydroxyl group is directly attached to a carbocyclic aromatic ring, but also heterocyclic compounds in which the hydroxyl group is attached to a ring containing a sulfur, oxygen, nitrogen or other atom and in which the hydrogen of the hydroxyl group so attached is suiliciently acidic to give the compound an ionization constant within the range defined above, said com pound being capable of forming an oil-soluble metal salt. It is to be further understood that the term "phenols includes not only monohydroxy but polyhydroxy compounds and those in which more than one ring is present, such as naphthols and the like. In addition to the hydroxyl group or groups, the ring is preferably substituted by one or more other substituents such as for example, an alkyl group or a sulfur atom linking two phenolic radicals together such as in dipara-tertiary-amyl diphenol sulfide, the only limits being that the compound must be noncarboxylic, and must contain at least one hydroxyl group of sufllcient acidity to exhibit an ionization constant within the limits described above, and must form an oil-soluble metal salt. For the sake of simplicity in the following specification and claims, these compounds will be referred to merely as the metal salts of phenols.

Although it is not definitely known why the metal salts of phenols act to prevent corrosion of alloy bearings and I do not wish to be bound by the theory, it is presumed that this inhibiting power is at least in part connected with the ability of the salts to react with the corrosive acids formed or present in the lubricating oil, to form non-corrosive metal salts of the corrosive acids, thereby liberating the non-corrosive, weakly acidic phenolic compounds. As an indi-- cation of the manner in which the above mentioned compounds are presumed to react to neutralize corrosive acidity, thereby rendering the oil non-corrosive, the following exemplary equation may be given:

ical, M represents a metal, X represents the acid radical of the corrosive acid, and H represents a replaceable or acidic hydrogen atom.

All oil-soluble metal salts of phenols, when dissolved in lubricatin oil, will tend to inhibit the corrosion of bearings of the cadmium-silver and copper-lead type. These include, and I may employ, the oil-soluble Li, Na, K, Cu, Zn, Mg, Ca, Ba, Sr, Al, Pb, Ni, Co, Mn, Cr, Sn and Fe salts of the phenolic compounds. I particularly prefer to employ the alkaline earth salts, calcium, barium, magnesium and strontium, and probably also the aluminum and zinc salts, of the phenolic compounds because of their greater solubility in oil and their possibly lower catalytic activity.

My invention, therefore. resides also in alubricating oil containing a small amount of an oil-soluble metal salt of a phenolic compound either alone or in combination with other constituents, for example, those adapted to enhance the oiliness or film strength of the oil, or even a neutral common solvent, such as the higher boiling alcohol-ethers, adapted to increase the solubility of the metal salt in the oil.

Also, the invention includes the use of these salts in lubricating oil in the indicated proportions, in combination with small amounts of other types of oil-soluble soaps having "detergent" properties in the engine,in proportion sufficient to overcome or greatly retard the deposition of resinous and varnish-like materials upon piston rings, valves and the like. One type of detergent soap which may be employed in conjunction with the corrosion inhibiting soap described above is the oil-soluble metal sulfonates, preferably the alkaline earth metal sulfonates such as barium, calcium, strontium and magnesium and preferably calcium sulfonate, or the alkali metal sulfonates such as sodium or potassium sulfonate, or the sulfonates of other metals such as copper, zinc, aluminum, lead, nickel, cobalt, manganese, chromium, tin and iron. Some of these sulfonates are more fully described hereinafter and in my mentioned patent application Serial No. 345,844 filed July 16, 1940.

These metallic sulfonates are especially valuable additives to mineral lubricating distillates. especially those which are highly parafllnic in of lower V. I., often are desirable.

lubricatingdistillates,suchas60to80V.I.dis-

tillates, or 40 to 60 V. I. distillates or even those tage of the distillate lubricating oils appears to be that they produce carbon in the engine which is much less abrasive than that from residual oils such as the ordinary Pennsylvania bright stock used for lubricating purposes. The distillates also show a lower Conradson carbon value than the residual type lubricatingoils. These advantages are also obtained when the anti-corrosion salts are added, and also when other detergent soaps are employed. The invention extends also to all these aspects. In addition, residual type lubricating oils can be used with these soaps for some uses but ordinarily the carbon formed is of objectionable type.

The term Viscosity index (V. I.) is defined in Chemical and Metallurgical Engineering, vol. 36, No. 10, pages 618-619 (1929). It is an indication of the type of oil, whether more or less paraflinic or naphthenic, a paraffin base oil being assigned 100 V. I. and certain Gulf Coast naphthene base oils being assigned zero V. 1., so that mixed base oils have intermediate values. Thus, the high V. 1. oils are the so-called highly "paraflinic oils, such as Pennsylvania oils and those highly refined with selective solvents such as phenol, aniline, liquid sulfur dioxide, nitrobenzene, furfural, dichlorethyl ether and the like.

The mentioned sulfonate soaps may be used in the indicated oils in amounts in the order of 0.5% to 1.5% as required to accomplish the desired result. Other types of detergent" soaps, which are used in similar proportions, are produced from soap-forming fatty acids and modified fatty acids such as the calcium and magnesium soaps of phenyl stearic acid and chlorostearic acids, and from naphthenic acids, rosin acids, modified rosin acids, and synthetic petroleum acids formed by the oxidation of petroleum fractions such as highly solvent-treated paraffinic type lubricating oil fractions, paramn waxes, petrolatum and the like. -Other metals may be used for soap production, as heretofore indicated, where sufllciently oil-soluble soaps are produced.

Where low V. I. oils are used, the mineral lubricating oil employed may be a California or a naphthenic-type oil which ordinarily contains about 0.5% of organically combined sulfur, but may contain as little as 0.15% of such sulfur. Higher sulfur content oils such as those derived from Santa Maria Valley (California), crude oil containing up to 4% or even 5%, for example, 2.75% of such sulfur, are sometimes very desirable. These are all distillates of low Conradson carbon value. This sulfur also tends to inhibit bearing corrosion and the formation of the acid condition causing it, as elsewhere herein indicated. With metal salts of adequate oil solubility, as in the case of the calcium salts of phenolic compounds containing hydrocarbon side chains attached to the ring, as indicated below, the base may be a well refined parafllnic-type oil.

The advan- The oil-soluble metal salts such as the calcium salts of the phenolic compounds are employed in the lubricating oil in amounts up to about 3%. but in amounts less than that required to cause an undesirable thickening of the oil, the optimum apparently being from about 0.5% to 2.0%.

A specific usable phenolic material of which I have produced the calcium salt is di-paratertiary-amyl diphenol sulfide, which apparently has the formula:

Alkyl hydroxy phenyl thio ethers of this type are described in the Mikeska et al. Patent No. 2,139,766 and other similar compounds and their method of preparation are given in Mikeska et al. Patent No. 2,139,321.

A phenolic material believed to be kindred to that of the Mikeska et al. Patent No. 2,139,766, is at present obtainable on the market under the trade-name Paranox which is available from the Standard Oil Development Company. This material, apparently, is in general composed of mixed poly-alkyl poly-phenol sulfides, that is, polyalkyl-substituted hydroxy phenyl thio ethers containing, for example, a thio ether of butyl phenol which may be designated as his (2-hydroxy-4-butyl phenyl) sulfide. This commercial product apparently contains various materials of the following general formulas:

R(CcHsOH) S(CcH3OH) R and R CsHaOH) S (CsHzOH) R.S (CeHaOH) R In these formulas and similar formulas herein S in general indicates one sulfur atom, but in some molecules two or more sulfur atoms may be represented, the major proportion, however, preferably being mono-sulfides; R is an alkyl group preferably containing four or five carbon atoms (but may contain more) which groups may be different for the different components of the mixture or may be different for the two or more benzene nuclei in one of the components. R, S and OH may occupy any of the possible positions in the benzene rings. The material may contain higher polymers such as indicated in the second formula above, and even more extensively polymerized materials.

The metal salts of the above described phenolic materials may properly be considered soaps because of an apparent detergent action. When about 1% or between about 0.5% and about 2.0% or 3.0% of such a suitable oil-soluble salt such as the calcium salt is dissolved in mineral lubricating oil. it has the combined effect of imparting to themineral lubricating oil where intended for severe service internal combustion engines, some required detergency characteristics and at the same time of acting apparently as a neutralizing agent or, at least in some manner, as an agent for preventing the corrosion of bearings such as those of cadmium-silver and copper-lead alloys.

The invention, therefore, also includes the use of oil-soluble metal salts of the indicated phenolic type of sulfur-bearing acidic materials, particularly the calcium salts. It also resides in the use of between about 0.5% and about 3.0% of such salts in mineral lubricating oils and especially between about 1.0% and about 1.5% of the calcium salts of the alkyl polyphenol sulfides or polysulfide materials described, especially where the lubricating oils are for use in Diesel engines or other severe service equipment.

In practicing this phase of the invention commercially, the salts of suitable phenolic compounds such as the calcium salts of dibutyl or other alkyl or mixtures of alkyl phenol sulfides above indicated may be formed without particular difliculty by any suitable procedure, as will be obvious to the skilled chemist. For example, the calcium salts of these compounds may be conveniently obtained by first adding the starting material to an approximately equal quantity or even greater quantity of a suitable lubricating oil such as a naphthenic base mineral oil having good solvent properties for the phenolic material and for the salts to be produced. This oil mixture is then commingled with hydrated calcium oxide and a small proportion of water, followed by heating to about 300 F. with agitation for a time sufficient to insure neutralization and dehydration. The resultant mixture is filtered to remove solids such as excess calcium oxide. (calcium content) has been increased when desired by first heating only to about 200 F. to 210 F. for a time to insure complete admixture and partial neutralization, the mixture being then cooled to 150 F. to 170 F. and a small quantity in the order of about 3% of 95% alcohol added, and the temperature of th mix then raised to the previously mentioned temperature of 300 F. Another method employed has been to neutralize the alkyl phenol sulfides with sodium hydroxide and then by metathesis with calcium chloride or the like, convert the sodium salt to the calcium salt. In preparing for treatment of the Paranox described above as probably comprising a mixture of alkyl phenol sulfides, about 20% of the sulfides should appear in about 80% of lubricating oil having good solvent power for the soap. Otherwise, a greater proportion of lubricating oil is added as its salt-dissolving power decreases. The above described neutralization to produce the calcium salts thereof is more or less easily accomplished due to the fact that the pure phenolic material has been found to have an acid number of about 98. The other alkaline earth metal salts may also be readily produced in a similar manner. In preparing salts of other metals previously mentioned, the metathesis procedure just mentioned may be preferable as will be readily determined by the skilled chemist. These operations yield concentrates consisting of salt in oil.

These salts are readily soluble in lubricating o'ls in the required proportions and yield alkaline solutions. Representative salts thus produced appear to have the following structural formulas:

and

In preparing Diesel engine lubricating oil according to the present invention the salt, or the The ash salt-oil mixture or concentrate, is stirred into an appropriate mineral lubricating oil and solution is efl'ected by agitation, a slight elevation of temperature being producedif desired to facilitate the solution operation.

When the calcium salt is dissolved in the lubricating oil to yield in the final product a salt content in the order of about 1% to 1.5% or in amounts from about 0.5% up to about 3.0%, the detergent action of the resultant lubricating oil is suflicient to overcome or prevent the deposition of the objectionable amounts of said resinous and varnish-like materials above mentioned, and at the same time this quantity of salt is insufilcient to increase substantially the original viscosity of the base mineral lubricating oil. Not only do the calcium salts of these alkyl phenol thio-ethers produce such detergency and thereby prevent sticking of rings and valves and the deposition of varnish-like coatings, but at the same time they prevent the formation of objectionable corrosive acid conditions which attack materially the highly corrosion-sensitive alloy bearings of the copper-lead type.

In addition to the general functions of a soap which are imparted to the oil by this calcium salt, the presence of the sulfur in the salt molecule tends to impart to a non-sulfur-containing lubricating o l extreme pressure characteristics, and the small percentage of actual sulfur present in the salt further acts to impart in itself some anti-corrosive properties.

In addition to the calcium salts of the phenol thio-ethers indicated, other metal salts of the alkylated phenol thio-ether may be employed such as those of barium and magnesium and also znc, and aluminum, the important requirements being good solubility in the chosen mineral lubricating oil, detergent properties and freedom from appreciable viscosity increase when used in detergent quantities such as the indicated range from about 0.5% to 2.0%. Also, these particular metals appear to possess less undesirable catalytic activity than some of the heavier metals previously mentioned such as lead. Salts of other phenol ethers such as alkyl-substituted phenol selenium or tellurium ethers or the like containing other suitable sulfur substitutes in the ether position are also wthin the scope of this invention for some uses where possessing sufllcient solubility in oil and adequate detergent properties.

I have also found that amyl phenol can be condensed with formaldehyde under appropriate conditions to form a viscous polymer in which free hydroxyl groups of the phenolic type are present. By d ssolving this resinous phenolic material in nine volumes of lubricating oil and saponifying by heating with an excess of hydrated lime, followed by dehydration and filtration in the manner described above, I have been able to form the calcium salt of this phenolic res n. When about 1.5% of such a suitable oilsoluble calcium salt was dissolved in mineral lubricating oil it was found to possess the required detergency characteristics and, at the same time.

acted to prevent the corrosion of bearings of the cadmium-silver and copper-lead type,

Further, I have found that stearyl alcohol can be condensed with phenol (monohydroxy benzene) in the presence of concentrated sulfur c acid to form a compound believed to be parastearylphenol. The calcium salt of this compound has likewise been readily formed in the manner described hereinabove and a lubricating oil possessing about 0.65% of the calcium salt of stearylphenol has exhibited the desired detergent and corrosion-preventing properties.

In the foregoing disclosure, the oil-soluble metal salts of phenolic compounds have beenpreferred, but it is to be understood that the oil-soluble metal salts of other weakly acidic, non-carboxylic'compounds having ionization constants within the range specified hereinabove are equally satisfactory and are within the scope of the present invention. As group examples or other such weakly acidic, non-carboxylic materials, the .phenols, thiophenols, other. enols, oximes, sulfonamides and the like were previously mentioned.

The following are specific examples in addition to those given above of suitable acidic materials from the classes just mentioned, and include aryl and alkyl substituted phenols and others of the classes mentioned.

In these instances the designation of the various groups by m and n is to provide the respective molecules with sufllciently high molecular weights to yield'salts of good solubility. in oil. Where the molecule has two rings, it appears that the molecular weight of a salt of good oilsolubility is around 350- or higher, There may be some instances where a salt of as low as 300 molecular weight will be sumciently oil-soluble, but such apparently is not true of all cases. In

general the same lower limits of molecular weights has been taken as representative of salts of suitable acidic materials of other chemical configuration. Varying values for m and n also indicate complexity in the molecules, which appears to be a desirable feature imparting greater oil-solubility. Branching appears to promote oilsolubility. Further, mixtures of different molecules in which the alkyl groups vary appear to have better oil-solubility than materials representing a single molecule. Thus, these materials may contain alkyl groups (or aryl groups where indicated) in which n, or m and n combined, may be smaller when the molecules otherwise have relatively high molecular weights, and larger when the molecules otherwise have relatively lower molecular weights. In general it may he said that m and n will have values from zero to perhaps as high as 20 or possibly higher for molecules otherwise of low molecular weight, and from zero to perhaps about 10 for molecules of otherwise higher molecular weight. Where different groups appear in the same molecule as indicated by the presence of both m and n, the number of one will decrease as the other increases at least toward the upper limit, whereby to avoid undesirably high molecular weights.

The following examples of these materials are arranged according to'groups above mentioned:

' I. Phenols Mflnohydroxy phenols 1 gone-.0111

. I onmon.

H0 om ..-cmcm).om

(b) Yulyhydrorypbemls 1 OQHI can cntdcm cmcom H CsHn H (Condensation product of p-tert. amylphenol and formaldehyde) 2 on. noQ-tzmonm-omcnmom (As in condensation oi oleyl alcohol and phenol) Q iQls (B may represent groups from propyl to deoyl for example) Here, R represents either an aryl group such as or an alkyl group such as amyl, butyl or other group between ropyl and decyl, or an ester group or the like. Also, at east one B may represent a halogen such as };'li]t0l'lll or other suitable iilm strength or kindred subs uen 6. Products of the type in all previous examples in which HO OH and the like appear in place of (c) Condensed ring lphenols 1 1. Products oi t e type in (a) an (b) above in which (d) Heterocyclic henols l. Compoun of the types in (a), (b), (e) above in which C) 0 Il/o on and the like appear in place 0! II. TIM

An OH group in the phenol compounds of Group I is replaced with SH.

( cn. cm).cn=Non (b) cn,(cm)..o(om)..cm

CHKCHDJIJ CHa(CH|)-. CH=NOH IV. Sulj'onamidea (a) crmom). ommomncn,

omwm). own (Crimea,

crmom). 0,.Nn

V. Imilio n (a) cm(om).omco

n cmwmncm-oo (o) CHI(CHI)I\ VI. Enolc (a) CH;(CH:)-OC=CH(CHl).CH|

crnwm).oH=c cO-(om)..om

' on g Oil-soluble salts of these various materials may be prepared in manners as outlined above and added in indicated proportions to yield the type of product described and claimed. Important requirements are good solubility of the salts in oil in the proportions required, without substantial increase in the viscosity of the base oil, and low ionization constants as above defined with consequent freedom from development of corrosive conditions in the oil during engine use which is presumed to be due to the indicated neutralizing character of the salts which may be termed reserve alkalinity.

The metal salts of the phenols above indicated may be viewed also as metal oxides or as phenolates, and where they contain sulfur in the ether position as in Group 4 under polyhydroxy phenols they may be viewed also either as sulfides or as thio ethers.

The present invention resides also, as has been indicated, in mineral lubricating oils containing small amounts in the order of from about 0.3% to about 2.0% or 3.0% of an oil-soluble metal salt of a sulfonic acid to insure good detergency, together with a quantity of approximately the same order of oil-soluble anti-corrosion metal salt of high molecular weight non-carboxylic weak acid of low ionization constant such as those herein described, which weak acid salts are to assist detergency and particularly to avoid development of the mentioned corrosive conditions. These weak acids include particularly the mentioned phenols and thiophenols. The sulfonic acids are described in detail below. The metal sulfonates and the metal salts of the above mentioned weak acids, when present together in a mineral lubricating oil in the amounts indicated above, produce an oil which is noncorrosivc to alloy bearings such as those composed of cadmium and silver or copper and lead. Further, such an oil has a reduced tendency to cause deposition of varnish-like, resinous or carbonaceous materials in the combustion chambers or on the pistons or piston rings.

The oil-soluble metal sulfonate may be a salt of the so-called mahogany acids. The sulfonate preferably is in the form of the calcium salt. However, the other alkaline earth metal salts or soaps. such as barium, strontium and magnesium soaps may be employed. Also the alkali metal soaps are often useful, and sometimes the heavier metal soaps are useful such as the soaps of copper, zinc, aluminum, lead, nickel, cobalt, manganese, chromium and iron. The anti-corrosion salts of the weak non-carboxylic acids are from acids having ionization constants of 5 10 or less and preferably of lxlH or less, such as 1 10- or within the range of 1x10- to 1x10-". The salts may be in the form of lithium, sodium, potassium, copper, zinc, magnesium, calcium, barium, strontium, aluminum, lead, nickel, cobalt, manganese, chromium or iron salts, but I prefer to employ the alkaline earth metal salts, e. g. Ca, Mg, Sr and Ba. 0! this group of weak acid salts, I prefer to use the oil-soluble metal salts of the phenols.

This phase of my invention is particularly novel in that the combination of salts of weak acids with the salts of the sulfonic acids has beneficial effect on the detergent properties of the oil and on any tendency toward development of corrosive conditions in the 011 during use, which effect is not obtained when the substances are used by themselves. This effect can result from the use of smaller combined amounts of the materials than can be even approximated by the collective results from the separate use of larger amounts of the individual materials. Neither alone is sufficiently detergent. This will become evident from the examples given hereinafter. This is possibly explained by a theory that the salt of the weak non-carboxylic acid improves the colloidal property of the sulfonate in the oil and thereby enhances the detergency of the sulfonate. Also, the sulfonate may cause improvement in the functioning of the weak acid salt. Although the combination may be used in any good lubricating oil (including naphthenic base oils--low V. I. oils), it was found to be unexpectedly satisfactory in oils of a high viscosity index (V. I.), for example, especially distillate lubricating oils with a V. I. of to 95, possibly because of the unexpectedly high solubility" or dispersion in this type of oil. For activating the anti-corrosion salts, the small proportions of water heretofore indicated as lying between about 0.002% and about 0.02% are important, even if not essential; the lower proportions are commonly used with the high V. I. oils. For also activating detergent soaps the higher proportions of water mentioned, e. g. 0.04% or 0.05% to 0.25%, are important.

The sulfonated acidsemployed to prepare the sulfonate additive of this invention may be those synthetically produced, as by du Pont of Wilmington, Delaware, and obtainable on the open market, or those obtained from the treatment York city. Acids of the latter type. which are valuable here, are the oil-soluble so-called "mahogany acids.

The mahogany" acids are well known to the industry. They are those sulfonic acids which are formed when lubricating oil fractions or similar petroleum oil fractions are treated with concentrated or fuming sulfuric acid. These socalled mahogany" acids dissolve in the oil phase, whereas the so-cailed "green" acids are the watersoluble sulfonic acids which pass into the sludge. The mahogany acids may be recovered by treatment of the oils with sodium hydroxide to produce sodium sulfonate which is removed from the oil solution by means of the addition of an alco hol such as ethyl alcohol or propyl alcohol with heating whereupon the sodium sulfonates pass into the alcohol solution which is separated from the oil, the alcohol being then distilled oil to leave the sodium sulfonates.

Sulfonates usable here may be sodium or potassium sulfonates, calcium or other alkaline earth metal sulfonates, or sulfonates of the heavy metals herein mentioned. Calcium is preferred.

Sodium salts of suitable oil-soluble sulfonic acids ofthis type from petroleum are obtainable from the Sonneborn Company under the trade name Petronate" which contains about 60% sulfonates and about 35% to 40% mineral lubricating oil. These salts, or the potassium salts, sometimes may themselves be used, at least in some combinations.

In order to obtain the calcium sulfonate from this mahogany acid soap, the sodium or potassium sulfonate is dispersed in hot water and a solution of calcium chloride is added with agitation while maintaining the mixture near the boiling point of water. The result is the formation of calcium sulfonate in a. sodium chloride and calcium chloride water solution. The mixture is cooled to coagulate the water-insoluble calcium soap, the water solution is drawn off, and the calcium sulfonate mass is washed with water in the cold. In order to eliminate all of the water and the remaining sodium chloride, from two to three volumes of mineral lubricating oil, based on the calcium sulfonate, are added to the calcium sulfonate mass and the mixture boiled until all of the water is eliminated, the temperature finally raised to about 325 F. or within the range of perhaps 275 F. to 375 F. During this treatment, the calcium sulfonate passes into solution in the oil, the water is driven off and the residual sodium chloride which crystallizes in the oil from the water droplets is then removed by filtering the hot oil solution. Incidentally, any other inorganic salts including excess calcium chloride will have crystallized and been removed along with the sodium chloride. 1

In one instance 900 grams of the sodium salts of oil-soluble petroleum sulfonic acids containing 40% of mineral oil were dispersed in 3000 grams of water and brought to a boil. To this was added 225 grams of calcium chloride dissolved in 1000 grams of water. The batch was agitated vigorously. The excess water was then expressed from the mass thrown down, and the mass washed with cold water with removal of the excess wash water. To the washed soap mass 2000 grams of lubricating oil such as described herein was added and the batch dehydrated as above. After addearth and heating to about 300' F., the batch was filtered. M

The resultant material was an oil concentrate containing about 0.05% water and about 20% of oil-soluble calcium petroleum-sulfonic-acid soap, which otherwise may be referred to here as a calcium mahogany acid soap, or calcium mahogany soap or calcium sulfonate. This concentrate is liquid at normal temperatures, is free from mineral salts, and, while it has an increased viscosity over the original oil, it has no typical grease-like characteristics, that is, it is free from all gel structure typical of greases. The soap is contained in the oil in what appears to be a state of perfect dispersion approximating possibly a true solution, which appears to be neutral and without the presence of anyappreciable acid number. e

For the present salt and soap combination, sufficient of this sulfonate concentrate will be employed toimpart to the oil a sulionate content of around 0.3% to 3%, approximately 1% representing an average use. These salts are readily dispersible in paraflinic base oils (preferably distiilates) of high viscosity index, as well as in naphthenic base oils, in proportions larger than required in the final composition. Even the'concentrate may be prepared with a high viscosity index oil, e. g. 90 v.1.

Where as the sulfonate additive is used primarily for its detergent properties, the weak noncarboxylic acid salt is added to activate or in-- crease the detergent properties of the sulfonate as well as to impart resistance to the development of corrosive conditions affecting the particularly corrosion-sensitive bearings. This second additive ordinarily may be used in percentages somewhat under those for the sulfonate. For example, if 0.8% to 1.5% of calcium sulfonate is used, then about 0.5% to 1%, or apparently sometimes as low as 0.2% or 0.25% of the weak-acid salt, will ordinarily be used. This is especially true of the phenol salts. In a specific case, 1.2% of calcium sulfonate was used with 0.7% of the calcium' salt of di-para-tertiaryamyl diphenol sulfide (Paranox) described, in a 90 V. I. lubricating oil distillate. The water content in the 'flnal blend was about 0.004%. This very small proportion of water serves to activate the neutralizing or corrosion-preventing characteristic of the phenolic or weak-acid salt.

While the oil-soluble anti-corrosion metal salts described, such as the calcium salts of the phen olic compounds. may be employed in the lubricating oil with detergent soaps in small amounts from about 0.2% up to about 3%, the optimum of such anti-corrosion salts is apparently from about 0.5% to about 1.5%. The proportion is to be less than that which will cause any undesirable thickening of the oil in conjunction with the detergent soap. A specific preferred material of this type usable with the described sulfonates is the oil-soluble phenolic material just. mentioned which I have produced and described as the calcium salt of di-para-tertiary-amyl diphenol sulfide ("Paranox) in which th amyi group is believed to be para to the hydroxy position of the phenol. Similar alkyl phenol thioether salts may be used. The salts of these materials may be considered either as sulfides or thio-ethers, or as metal oxides or as phenolates or ing grams of a finely ground diatomaceous 75 as ethers, as may other similar suitable phenolic salts herein disclosed.=

In preparing lubricating oils according to the present invention, and according to this particular form of the invention, the salts and soaps or soap-oil mixtures or concentrates are stirred into appropriate mineral lubricating oils, and solution or dispersion of the salts and soaps in the oils is eil'ected by agitation, a slight elevation of temperature, such as around 125 F. or 130 F. being employed if desired to facilitate the operation. For example, where a "detergent soap of the sulfonate type" is employed in conjunction with an "anti-corrosion salt of the "Paranox type, these salts and soaps will be blended into or dispersed in the mineral lubricating oil in proportion to yield in the final product the total desired salt and soap content. Thus, a calcium sulfonate concentrate would be added to yield, for example, 1.2% of calcium sulfonate and about 0.7% of the calcium salt of diamyl diphenol sulfide in the final product.

The ratio of the quantity of the phenol salt to the quantity of the sulfonic acid soap may be varied, but preferably approximately or roughly equal quantities of the two compounds are generally used, that is quantities to yield substantially equal amounts of ash figured as CaSOr.

The proportions of salts and soaps as herein described are insufllcient to increase substantially the original viscosity of the mineral base lubricating oil. The salts and soaps employed in conjunction with one another give excellent detergency characteristics to the oil, while the phenol salt itself acts also as an alkaline reserve to prevent the formation of, or neutralize the effects of, the objectionable corrosive acids which attack detrimentally the highly corrosion-sensitive alloy bearing of the copper-lead type. This is especially true when employing the small amounts of water herein described.

In addition to the calcium salts of the phenol thio-ethers indicated, salts of other metals of the alkylated phenol thio-ethers may be 'employed, such as those of barium, magnesium and also zinc and aluminum, the important requirements being good solubility in the chosen mineral lubricating oil, detergent properties and freedom from appreciable viscosity increase when used in detergent quantities such as the indicated range from about 0.25% to 2.0% or possibly 3%. Also, these metals appear to possess less undesirable catalytic activity than some of the heavier metals such as lead. Salts of other phenol ethers, such as alkyl-substituted phenol selenium or tellurium ethers or the like containing other suitable sulfur substitutes in the ether position, are also within the scope of this invention for some uses where possessing sufiicient solubility or dispersibility in oil and adequate detergent properties.

In the foregoing disclosure, the oil-soluble metal salts of phenolic compounds have been preferred for use along with the sulfonates, but it is to be understood that the other mentioned oil-soluble metal salts of other weakly acidic, non-carboxylic compounds having ionization constants as specified above, are equally satisfactory and are within the scope of the present in- V vention.

As specific examples of the preparation of the combination of the invention and the effect of some of the herein-described materials, the following are presented:

One thousand grams of the above-mentioned oil-soluble sodium sulfonate in 40% oil, known as Petronate, produced by the Sonneborn Company, was agitated in 4000 cc. water during the addition of 220 grams CaClz in 1000 grams water. After complete metathesis, the product was washed and added to 2000 grams of a propanedewaxed highly solvent-treated highly parafllnic SAE 30 high viscosity index mineral lubricating distillate oil (about V. I.) together with about 25 grams of lime to insure complete neutralization. The mixture was dehydrated at 300 F. and filtered at 300 F. to give a filtrate Component I which was a dispersion of 600 grams of oil-soluble calcium sulfonate in 2400 grams of oil, 1. e. a 20% concentrate. It contained about 0.05% water.

To prepare the second additive for my composition, 2000 grams Paranox (amylphenol thioether) obtained from the Standard Oil Development Company, was mixed with 500 grams lime, 440 ml. 90% isopropanol and 8000 grams of the same high viscosity index (90 V. I.) SAE 30 motor oil mentioned in the above example. The mixture 'was agitated for two hours at 180 F., dehydrated for thirty minutes at 330 F. with 500 grams of diatomaceous earth to give Component II consisting of 2000 grams of calcium salt of alkyl phenol thioether together with some unreacted alkyl phenol thioether in 8000 grams of oil, 1. e. a 20% concentrate. It contained about 0.1% water.

These two preparations were added to a similar high V. I. (90 V. I.) solvent treated SAE 30 lubricating oil in quantities to give a composition containing 1.2% by weight of calcium sulfonate and 0.7% by weight of calcium salt of tertiary-amyl phenol thioether. The total water content was about 0.005%. This composition, on testing in Diesel engines running with a high load, proved to have excellent detergency properties. After the usual period of hours, the piston was free of lacquer deposit, and all of the rings were free and in good condition. The corrosion of copper lead bearings was also at a minimum.

However, using a similar high V. I. motor oil to which had been added 1.2% by weight in one case and 2.5% by weight in another case the calcium sulfonate alone, by means of Component I, the products showed relatively poor detergency action in Diesel engines. The use alone of about 2.0% by weight of the described calcium salt of alkyl phenol thioether by means of Com-ponent II, whose active ingredient was probably calcium diamyl-diphenol sulfide, in a higher V. I. oil gave a correspondingly poor lubricant for severe service engines. At the end of forty hours deposits had appeared on the ring lands and the rings were beginning to show symptoms of sticking, and on the piston skirt a quantity of a varnishlike material was noticeable.

The above two-component composition is illustrative of the various compositions which can be made under the above disclosures employing sulfonates and any other weak-acid salt having the reserve alkalinity property.

The invention further resides in the use of a small proportion of water in oils containing one of the aforementioned oil-soluble corrosion-controlling salts, either where such salt is employed alone or together with one of the aforementioned detergent" soaps. A small amount of water increases both the efliciency of the oil-soluble corrosion-controlling salts in mineral oil, and also the efllciency of the mixtures of oil-soluble corrosion-controlling salts and detergent soaps in mineral oil. Also a somewhat larger proportion of water, such as 0.05% to 0.3%, serves to activate the detergent soap and make it more eflicient. For example, the calcium salt "Paranox (alkyl substituted phenol sulfide) is more efficient as a corrosion inhibiting agent in mineal lubricating oil when a small quantity of water is present in the com-position. Again, when the described sulionate is also present, its detergency, in a low V. I. oil for example, is much improved by water as indicated. Apparently, this water may be present in the oil containing these agents, or it may be loosely bound to the agents themselves. In fact, in some cases the water may be bound to the agents in the form of water of hydration.

In general it may be stated that lubricating oil containing either the corrosion inhibiting agent alone or the corrosion inhibiting agent and a detergent, should also contain from about 0.002%

' 0.02% or 0.03%) water to 0.25 or 0.3% water to about 0.02% water, and preferably between I about 0.04% and 0.01% water, if it is to exhibit maximum anti-corrosion characteristics. In the examples given in my prior applications, Serial No. 305,496 filed November 21, 1939, and Serial No. 277,677 filed June 6, 1939, and also given herein, a method for producing the salt of "Paranox (alkyl phenol sulfide), was described in which the final salt produced contained ample water to exhibit optimum anti-corrosion properties when this salt is added to mineral oil either alone or in conjunction with the detergent soaps described above. Thus, a solution containing 80% mineral oil and 20% Paranox (alkyl phenol sulfide) is first blended with an equal volume of lubricating oil. This oil mixture is then commingled with hydrated lime and a small quantity'oi water, followed by heating to about 300 F. with agitation for a time to insure neutralization. This resultant mixture is then filtered to remove solids such as excess calcium oxide. The salt concentrates resulting from these operations contain about 20% salt and from about 0.1% or 0.2% to about 0.4% water. Providing this oil solution of calcium salt of alkyl phenol sulfide is blended with a further quantity of oil at a temperature of about or not materially higher than 130 F. the blended oil produced will contain sufflcient water to obtain maximum anticorrosion efliciency from this salt.

As has been indicated above it is also desirable that mineral oil which has been blended with an anti-corrosion agent (as defined in this specification) and a detergent (as defined in this specification), shall have present a small amount of water to activate or develop the maximum efllciency of the detergent as well as of the anticorrosion agent. This applies also to the action of the detergent soap apart from any anti-corrosion agent. It is possible that it is immaterial whether this water is held in the form of water of hydration by the additives or otherwise held loosely bound to these materials or whetherthe water is simply present in free form.

As has been pointed out the amount of water present in the mineral oil containing'the anticorrosion agent, or containing an anti-corrosion agent and a detergent soap, may, for purposes of activating the anti-corrosion agent, vary within the limits of about two-thousandths per cent (0.002%) to about two hundredths per cent (0.02%) in the final oil product, and preferably between about four or five-thousandths per cent (0.004% or 0.005%) and about ten or fifteenthousandths per cent (0.010% or 0.015%).

In addition, however, I have found that an appreciable increase of the water content tends furbased on the final product markedly enhances and phenolates as herein described, and apparently produces the optimum efliciency. This detergency improvement seems to be the most pronounced when using the sulfonates as described. Also there is some evidence that this water produces the greatest improvement in detergent action of the blended product when the oils used are lubricating distillates of low viscosity index (e. g. 20 to 40 V. I.), rather than of high viscosity index oils (e; g. V. I.) even when distillates are used instead of residual oils.

The percentagewater content is perhaps best calculated initially upon the basis 01' the concentrate as initially made and as herein indicated. Normally these concentrates contain in the order 01' 20% soap or salt, and the range of water content will be from about one-tenth per cent (0.1 to about one per cent or more, depending upon whether one or both agents are to be activated. Where a single soap or salt is employed the whole water content required may be contained in that concentrate. Where two salts or soaps. are employed, two separate concentrates are preferably used and separately added. In this case it is possible that both concentrates can contain an appreciable proportion of the water or that one concentrate may be dry or approximately so and the other concentrate contain all or nearly all of the water.

The upper limits of the water content are perhaps more easily determined than the lower limits. It is ordinarily important to have enough water to activate'both the detergent soap and the anti-corrosion salt, which activation however is to be accompanied by less water than will aifect the compatibility of either the detergent or the anti-corrosion agent with the oil. Too much water may in some instance render the detergent or the anti-corrosion agent or both insoluble in the oil or affect their compatibility with each other. The amount of water therefore should be adjusted to avoid substantial reduction of the compatibility of either the anti-corrosion or detergent agent with the oil, or with each other. The term "compatibility may be defined here as the property of the materials to blend readily with one another without substantial tendency to precipitate or cloud. However, mere cloud or slight tendency to gel may be of no consequence so long as the oil when introduced into the engine contains the necessary proportion of con- I stituents. Engine agitation and engine heat will then adequately distribute and dissolve the additives. For practical puropses where the detergent soap is to be activated as well as the anti-corrosion salt, the upper limit conveniently varies apparently from about 0.1% to 0.25% or possibly 0.3% depending upon the detergent soap. Where the soaps will permit more water, apparently there is no added advantage.

The lower limit of water content from the standpoint of activating only the anti-corrosion salt, may in some cases be somewhat awkward to define. Viewed from the standpoint of the water in a 20% concentrate, rather than from the standpoint of the finished oil, the proportion apparently should be more than a mere detectable trace and should be an amount whose proportion can be determined. In the range of onetenth per cent (0.1%), or even as low as fivehundredths per cent (0.05%) the water content can be determined. Below that figure measurement is difficult and such amounts also are usually too low for effect. A convenient method for water determination is the Karl Fischer method described by Smith, Bryant and Mitchell in the Journal of the American Chemical Society, vol. 61 (1939) page 2407.

or course, it is to be understood that in some combinations the indicated lowest permissible percentages do not sufficiently activate the anticorrosion agent. For example, some detergent soaps, such as the salts of the oxidation of acids from paraiiinic type compounds, develop corrosive conditions in an engine more readily than do sulfonates. Apparently in the case of these more active carboxylic acid soaps, the anti-corrosion agent needs to be activated more rapidly and more readily than when using agents which develop corrosiveness not at all or more slowly, such as the sulfonates. Therefore when the sulfonates are employed less water is required than where carboxylic acid soaps are employed. Similarly, if no detergent agent is employed, the only corrosiveness that develops apparently is due to that from acidic materials formed in the engine merely under engine conditions. For example, if the so-called Paranox type of salt is used alone, less water will be necessary than when used with carboxylic acid soaps.

Again, from the standpoint of activating only the anti-corrosion salt, it appears that in the case of oils which possess a high viscosity index or low viscosity gravity-constant (highly parafflnic oils or oils which have been heavily treated with solvents such as phenol, dichlorethyl ether, sulfur dioxide or nitrobenzene), it is usually desirable to use only a relatively small amount of water. At any rate, this is true where "detergent" type soaps having low tendency toward catalysis of oxidation (such as sulfonates) are used along with the anticorrosion type salts in high V. I. oils. For example, where the calcium salt of the alkyl diphenol sulfide (Paranox) and calcium sulfonate are blended with an oil of low viscosity gravityconstant (high V. 1.), about 0.002% to 0.006% of water is usually suflicient. (Viscosity gravity constant, V. G. C., is defined by Hill and Coats in Journal of Industrial and Engineering Chemistry, vol. 20, page 641, 1928.) Again, where detergent soaps of carboxylic acids are used with anti-corrosion salts of the phenolic type in low V. I. oils, e. g. 20 V. 1., the higher ranges of water are required to activate the anti-corrosion agent. It is not known whether the smaller proportions of water may be used under most conditions in an oil of high viscosity index merely because of the character of the oil, and/or its soap content, or whether for some reason the composition can pick up water rapidly enough during engine operation, as by reason of water vapor blown past the pistons from the combustion chamber, which accession does not occur rapidly enough in the case of low viscosity index oils, i. e. naphthenic type. Also, the greater the percentage of phenolic type salt required, the greater also will be the proportion of water required in the oil composition. The aspect of water content to activate the detergent soaps was described above.

A further feature of invention is found in the fact that relatively smaller proportions of free acidic materials from which the soapsare prepared are sometimes highly beneficial in promoting compatibility of the various soaps in the oil concentrates or in the final product. This may be, for example, in the order of perhaps as low as two per cent to ten per cent or even more based on the soap content. Where weak-acid salts such as the phenolic type used for anti-corrosion agents are concerned, no compensating agent is required. This is true, for example, where a Paranox salt oil contains 8% or 10% of free Paranox" based on the Paranox" salt content, which is especially valuable when used in conjunction with carboxylic acid detergent soaps, e. g. soaps of synthetic acids from the oxidation of highly parafiinic petroleum fractions, However, where stronger acids, such as carboxylic acids, are used for the detergent type soaps, any such free acid, as where used to improve compatibility to facilitate handling for example, will be neutralized by the anti-corrosion agent on blending. Therefore an additional amount of anti-corrosion agent suflicient to care for this neutralization must be used.

As to anti-corrosion salts, I have also found that phenolic materials whose salts may be used either alone or with detergent type soaps such as the described sulionates, are phenolic materials resulting where alkyl phenols such as an amyl phenol are condensed with formaldehyde. The water contents required in resultant oil compositions will be the same, under the different conditions, as described above. The alkyl Phenol can be condensed with formaldehyde under appropriate conditions to form a viscous polymer in which free hydroxyl groups of the phenolic type are present, and appropriate oil-soluble salts such as calcium soaps canbe produced therefrom. For example, I have manufactured the condensation product of p-tertiary amyl phenol with formaldehyde employing both an acid catalyst and a basic catalyst. Where employing an acid catalyst I have used about 82 grams (0.5 mol.) of amyl phenol with from about 27 grams to about 49 rams (0.33 to 0.5 mol.) of 37% formalin (formaldehyde) with 2 ml. of 37 of hydrochloric acid. These materials were combined and refluxed for one hour where the higher molecular proportions of formaldehyde were used and up to three hours where the lower proportions of formaldehyde were used. The refluxing temperatures were conveniently carried between about 200 F. and 212 F., any appropriate range obvious to the skilled chemist being suitable. When the condensation product was formed by refluxing as above, a thick liquid, resinous material was obtained when the smaller proportions of the formaldehyde were used and a more pasty material when the higher proportions of formaldehye were used. In these cases the resultant liquid or paste as one part was then added to nine parts variously of SAE 20 and SAE 30 grades of California or naphthenic base mineral lubricating oils and high viscosity index '(80 to V. I.) parafllnic lubricating oils. These were mineral lubricating distillates. (In some cases, there was added to this mass the water layer from the refluxing opera.- tion, this water being that of the formaldehyde solution.) To this mass there was then added 37 grams (0.5 mol.) of hydrated lime and the batch was agitated for two hours at temperatures ranging between F. and 200 F., and then cooled. In some instances 60 ml. of ethyl alcohol was then added and the batch further agitated for about two hours at 180 F. Where alcohol is used there is less hydrolysis and the calcium content is increased. In each instance the temperature and time of treatment and the nature of the treatment was such as to eifect conversion 01' the phenolic resin into the calcium salt thereof. In order to remove completely any unconverted lime and other solvents there was mixed into the batch a quantity of suitable fllter aid such as ground diatomaceous earth (e. 8. "Super-Gel) approximating the amount of the hydrated lime employed (about 37 grams), and the batch heated to 300 F. and filtered at about that temperature.

Suitable resins were produced in the same manner by employing 2 ml. of ammonium hydroxide containing 28% NH: as the catalyst instead of hydrochloric acid, the refluxing in these particular cases being slightly longer, the results apparently being equally satisfactory.

These products constituted concentrates, that is. 10% of the calcium salt of the phenolic condensation product with 90% of the naphthenic mineral lubricating oil mentioned. These concentrates were dilutable in all degrees with either naphthenic base oils or paraiflnic-type lubricating oils without precipitation of the salt after long standing. A higher salt concentrate can be obtained by using smaller amounts of oil',

although the larger amounts render, the mass more workable.

The same salts have also been prepared directly by adding the hydrated lime to the original mass, thereby employing the lime as a catalyst. Thus 82 grams of amyl phenol, 328 grams of the mentioned 600 viscosity mineral oil and 3'7 grams of hydrated lime were charged into a closed flask,

having a sealed agitator and a reflux condenser,

the phenolic condensation product with the form aldehyde and its conversion into the calcium salt thereof was effected directly in one operation to yield a concentrate containing salt.

Other alkyl phenols than amyl phenols where the alkyl group contains at least 4 carbon atoms such as butyl, hexyl, octyl, nonyl, decyl and others of 11 and morecarbon atoms per group may be employed as has been indicated above. and other metals than calcium, particularly the other alkaline earth metals and the light metals aluminum and zinc, may be employed in the formation of the oil-soluble metals salts. These salts may be considered either as phenolates or as metal oxides in which the rings carry alkyl groups to weight to render them oil-soluble.

rther, I have found that stearyl alcohol can be condensed with phenol (monohydroxy benzene) in the presence of concentrated sulfuric acid to form a compound believed to be parastearylphenol. Salts are prepared in manner similar to that described above. The metal alcoholates, such as aluminum, zinc, calcium and sodium alcoholate, where the alcohol consists of a hydroxy group attached to an alkyl, aralkyl, or cycloalkyl radical, also have value in use with the sulfonic acid soaps. The stabilizing efie'cts which these alcohols alone impart to lubricating oils are described in the Shoemaker et al. Patents insure sufliciently high molecular Nos. 2,057,212 and 2,125,961, but the combination of these alcoholates with the metal sulfonates not only increases the inherent detergent properties of the metal sulfonates, but also the alcohols retain their beneficial stabilization characteristics. These materials also may be considered as metal oxides.

As specific examples of the two types of oils used to produce products of this invention, and examples of the products themselves, those in the following table are furnished. Both oils are distillate oils. The one is a typical Western or naphthenic base oil of low viscosity index (about 15 V. 1.), and the other is a high viscosity index oil (about V. I.) of parafllnlc type such as produced by propane dewaxing a Western paraflinic and naphthenic distillate (from Santa Fe Springs, California, crude) and then heavily solvent treating the same as with phenol to eliminate the naphthenic and kindred constituents. The paraiflnic type blend, and also Blend A of the napthenic type, contained enough water to improve or activate the anti-corrosion properties of the sulfonate beyond that where the oil was dry. Blend B of the napthenic oil contained enough water to activate or improve also the detergent properties of the phenolic salts. Both types of oils, being lubricating distillates instead of residual type lubricating oils, had relatively low carbon residues (below 0.2) and developed only mildly abrasive or non-abrasive carbon in the engines, as distinguished from typical residual Pennsylvania lubricating oils which have Conradson carbon values in the order of 0.40 to 0.50 and develop highly and therefore objectionably abrasive carbon in the engines.

Lubricating oil specifications Parafilnic type Na phthemc type low v. I. distillate Base Base Blend Blend oil Blend oil A B S. A. 20 20 so so 30 glscosity xndextW. I.) 89 89 l5 l8 l4 iscosity gravi y Constant (V. O 0.809 0. 814 0.877 0.881 0.881 Gravlty A. P. I. 60 F 29. 5 28.6 20.6 19.9 19.9 (four p gmft X F 10 10 -10 l0 5 .-0 or 5 5 2 4 4 Viscosity Saybolt Uni- M A versal:

At 100F .seconds. 352 385 582 029 045 At 210 F do 54.2 56 55.7 57.4 57.5 Fire point C. O. C.F 520 520 415 415 415 Flash point C. O. C F 445 440 37 370 375 Calcium petroleum sulfonate (from Petronate).. percent 1.2 1.2 1.2 Calcium amyl phenol sulfide (from "Paranox") ..d0. 0.725 0.725 0. 725 Water... 0. 0.01 0. 0. Conradson carbon rosi' due 0.05 0.12 Sulfate ash 0. 45 0. 43 0. 45 Carbon residue plus ash. I 0. 57 l Neutralization No.

alcohol method) i 1 Soaps tend apparently to raise carbon residue to a value beyond original carbon residue and ash combined.

1 Slightly alkaline.

It is to be understood that these oils are illustrative of the generic invention and that they are not to be taken as necessarily limiting thereof.

I claim:

1. Lubricating oil comprising mineral lubricating oil and a small proportion of oil-soluble anti-corrosion non-carboxylic salt of a weakly acidic organic compound having an ionization constant below about 5 10- between about 0.2 and 3% not substantially increasing the original viscosity of the mineral oil, containing also between about 0.5 and 3% of detergent soap not substantially increasing the viscosity of the oil, and between about 0.002 and 0.3% of water to activate the anti-corrosion properties oi the salt.

2. Mineral lubricating oil containing a small proportion of oil-soluble salt of a phenol-thioether as anti-corrosion salt and a relatively smaller proportion of water to activate the anticorrosion properties of the salt.

3. Lubricating oil comprising mineral lubricating oil and a small proportion of oil-soluble alkaline earth metal salt of a phenyl thio-ether between about 0.2 and 3% as anti-corrosion salt not substantially increasing the original viscosity of the mineral lubricating oil, and between about 0.002 and 0.3% of water to activate the anti-corrosion properties of the salt.

' fractions.

tergent soap is from oxidation acids from highly 4. Mineral lubricating oil containing a small proportion of oil-soluble anti-corrosion non-cab. boxylic salt of a weakly acidic organic compound having an ionization constant below about 5 l0-, small proportion oi oil-soluble detergent soap, and a relatively smaller proportion of water not exceeding about 0.3% to activate the corrosion-controlling properties of 'tlie anti-corrosion salt.

5. Freely liquid lubricating oil comprising mineral lubricating oil containing a small proportion of oil-soluble anti-corrosion salt of weakly acidic non-carboxylic organic compound having an ionization constant below about 5X 10-, a small proportion of oil-soluble detergent soap of relatively strong acid, and a relatively smaller proportion of water not exceeding about 0.3% to activate the weak-acid salt, the combined salt and soap contents not substantially increasing the original viscosity of the mineral oil.

6. Oil according to claim 5 wherein the anticorrosion salt is an alkaline earth metal salt.

7. Lubricating oil' comprising mineral lubricating oil, a small proportion between about 0.2% and 3% of alkaline earth metal oil-soluble corrosion-controlling salt, of weak non-carboxylic organic acid having an ionization constant below about 5 10-, between about 0.5% and 3% of alkaline earth metal oil-soluble detergent soap of stronger acid, and between about 0.002% and 0.3% of water.

8. Oil according to claim 7 wherein the anticorrosion salt is salt of a diphenol sulfide.

9. Oil according to claim 7 wherein the anticorrosion salt is the calcium salt of di-alkyl diphenol sulfide.

10. Oil according to claim 7 wherein the detergent soap is calcium soap of synthetic oxidation acids from a highly parafilnic petroleum fraction.

11. Oil according to claim 7 wherein the salt and soap are calcium salt and soap, the detergent soap is from synthetic oxidation acids from highly parafilnic petroleum fractions and the anti-corrosion salt is from di-alkyl diphenol sulfide.

12. Oil according to claim 7 wherein the detergent soap is a sulfonate.

16. Oil according to claim 5 wherein the detergent soap is a carboxylic acid soap.

17. Oil according to claim 5 wherein the deparaflinic petroleum fractions.

18. Mineral lubricating oil containing an oilsoluble anti-corrosion salt of a weak non-carboxylic organic acid having an ionization constant below about 5X10-, and'an oil-soluble detergent soap of relatively stronger saponifiable organic acid, each salt and soap being present in proportions between about 0.2% and 3% insufficient to impart substantial viscosity increase to the original oil, the composition also containing a small proportion of free organic acid as a solubilizer for the salt and soap and a small proportion of water not exceeding about 0.3%. v

19. Oil according to claim 18 wherein the detergent soap is soap of oxidation acids of highly paramnic petroleum fractions.

20. Mineral lubricating oil according to claim 18 wherein the anti-corrosion salt is from an alkyl diphenol sulfide.

21. Mineral lubricating oil according to claim 18 wherein th anti-corrosion salt is from an alkyl diphenol sulfide and the detergent soap is a sulfonate from petroleum.

22. Mineral lubricating oil containing a minor proportion of oil-soluble metal salt of alkylated diphenol thioether and a small amount of water not exceeding about 0.3% to actuate the salt.

23. Oil according to claim 5, in which the detergent soap is a petroleum sulfonate.

24. Oil according to claim 5, in which the anti-corrosion salt is metal phenate and the detergent soap is a metal sulfonate.

25. Oil according to claim 5, in which the mineral oil is of high viscosity index.

26. Oil according to claim 5, in which the anti-corrosion salt is selected from the class consisting of phenol sulfide, telluride and selenide.

27. Mineral lubricating oil containing a small proportion of oil-soluble anti-corrosion salt of a weak organic non-carboxylic acid having an ionization constant below about 5X10- selected from the class consisting of alkylated diphenol sulfide, telluride and selenide and a relatively smaller proportion of water to activate the anticorrosion properties of the salt.

28. Oil according to claim 5, in which the mineral oil is a mineral lubricating oil having a low Conradson carbon residue.

CHESTER E. WILSON.