WO2002099016A2 - Heavy duty diesel engine lubricating oil compositions - Google Patents

Description

TITLE: HEAVY DUTY DIESEL ENGINE LUBRICATING OIL COMPOSITIONS

FIELD OF THE INVENTION

This invention relates to diesel engine lubricating oils. More particularly, this invention relates to heavy duty diesel engine lubricating oils containing alkali and alkaline earth metal salts. BACKGROUND OF THE INVENTION

Development of improved diesel engine lubricants has continued over the years. One area of performance that has received constant attention is the ability of a diesel engine lubricant to minimize piston deposits. Engine oils used to lubricate heavy duty diesel engines must control piston deposits. Lubricants containing highly basic (overbased) metal containing compositions are most frequently used to control piston deposits in diesel engines.

A number of standardized engine tests are available to measure the ability of a lubricant to control piston deposit formation in diesel engines. One particularly useful test is the Caterpillar 1-K test. U.S. Patent 2,943,052 relates to compounded mineral oil compositions containing certain mineral oils and a mixture of alkali metal sulfonate and alkaline earth metal sulfonate.

U.S. Patent 4,283,294 describes lubricating oil compositions suitable for use in marine diesel engines comprising 60 to 85 parts by weight of lubricating oil, 15 to 30 parts by weight of a mixture of more than 50 weight % of a Group Ila metal overbased detergent and up to 50 weight % of a group la metal overbased detergent and 0.2 to 5 parts by weight of an antioxidant provided the weight ratio of the overbased detergent mixture to antioxidant lies between 7.5 to 1 and 50:1.

U.S. Patent 4,952,328 relates to fully formulated lubricating oil compositions comprising inter alia, from about 0.01 to about 2% by weight of at least one basic alkali metal salt of sulfonic or carboxylic acid and optionally, at least one neutral or basic alkaline earth metal salt of at least one acidic organic compound. U.S. Patent 4,954,273 relates to compositions, especially diesel engine crankcase oils comprising an overbased salt of a compound represented by the formula

U.S. Patent 5,202,036 relates to a diesel lubricant comprising, inter alia, at least one basic alkali or alkaline earth metal salt of at least one acidic organic compound. U.S. Patent 5,232,616 describes lubricating oil compositions which contain

(a) a mixture comprising an oil-soluble alkali metal compound and certain polyalkenyl succinimide or (b) alkali metal salts of said polyalkenyl succinimides.

U.S. Patent 5,256,322 relates to lubricating oil compositions for methanol fueled internal combustion engines, the lubricating oil having a total base number from 9.0 to 14,0 and comprising a suitable base oil, overbased sodium sulfonate in an amount sufficient to provide a base number from about 1.0 to about 2.0 in said lubricating oil and at least one metal sulfonate selected from the group consisting of overbased calcium sulfonate, overbased magnesium sulfonate and mixtures thereof in an amount sufficient to provide a base number from about 8.0 to about 12.0 in said lubricating oil.

U.S. Patent 5,498,355 relates to lubricating oil compositions comprising a mixture of certain succinic dispersants and alkali and/or alkaline earth metal containing detergents to control accumulation of deposits, sludge and varnish on engine parts. U.S. Patent 5,558,802 teaches that neutral and overbased calcium salts of organic acids increase low temperature high shear viscosity of lubricant containing them. It is recommended that these calcium salts be avoided or limited. Where diesel performance is required, it is noted a calcium salt of an organic acid may be required to control piston deposits. In this circumstance it is taught that the amount of calcium salt should be kept between 0.0004 and 0.0007 moles per 100 grams of lubricant.

U.S. Patent 5,726,133 is directed to low ash natural gas engine oil which contains an additive package including a particular combination of detergents and other standard additives. The detergents comprise at least one low TBN alkali or alkaline earth metal salt or a mixture thereof, and at least one other detergent which is more neutral than the low TBN alkali or alkaline earth metal salt.

U.S. Patent 5,804,537 describes a low-phosphorous passenger car motor oil containing as a minor component a tri-metal detergent mixture wherein the tri-metal detergent mixture comprises at least one calcium overbased detergent, at least one magnesium overbased metal detergent and at least one sodium overbased metal detergent, wherein the tri-metal detergent mixture is present in the oil composition in an amount such that the total TBN contributed to the oil composition by the tri-metal detergent mixture is from about 2 to about 12, and wherein the calcium overbased detergent contributes from about 8 to about 42% of the TBN contributed by the tri- metal detergent mixture, the magnesium overbased detergent contributes from about 29 to about 60% of the total TBN contributed by the tri-metal detergent mixture and the sodium overbased detergent contributes from about 15 to about 64% of the total TBN contributed by the tri-metal detergent mixture. U.S. Patent 6,004,910 describes lubricating oil having an ashless nitrogenous

TBN source together with an ash containing detergent having a TBN in excess of 100, a magnesium source and metal dihydrocarbyl dithiophosphate. In particular, it comprises a major amount of lubricating viscosity having a sulfated ash content between 0.35 and 2 mass % and A) a nitrogenous TBN source; B)a metal salt of an oil soluble acid having a TBN in excess of 100; C) at least 500 ppm magnesium and D) at least one metal dihydrocarbyl dithiophosphate. The metal salt of an oil soluble acid provides at least about 40% of the total TBN of the composition. Overbased magnesium sulfonate may be used as the metal salt of an oil soluble organic acid having a TBN in excess of 100 and the additive providing at least 500 ppm (mass) magnesium.

EP 0 924 290 describes non-thixotropic, sodium-free lubricant additives having from 10% to 50% of a liquid organic diluent and from 30% to 90% of a substituted hydrocarbaryl metal salt wherein at least 30 mole % of the metal in the metal salt is lithium and the salt is essentially free of sodium. The base number of the non-thixotropic lubricant additive attributable to lithium is less than 150. The additive is described as being useful for decreasing black sludge deposits and piston deposits.

Deposits formed at high temperatures in heavy duty diesel engines can lead to increased oil consumption, piston scuffing and decreased engine life. It has now been surprisingly found that the amount of piston deposits in high temperature, heavy duty diesel engines lubricated with lubricants containing alkaline earth metal salts can be greatly reduced when a portion of the alkaline earth metal containing detergent is replaced with monovalent (alkali metal) detergents. It is particularly surprising that this has been accomplished without adversely impacting on other performance characteristics of the lubricating oil composition. SUMMARY OF THE INVENTION The present invention is directed to a composition comprising alkali and alkaline earth metal salts of at least one acidic organic reagent wherein from about 4.0 to about 10.3% of the TBN of said composition is provided by the alkali metal salt. In another embodiment, the composition comprises alkali and alkaline earth metal salts of at least one acidic organic reagent wherein from about 5.0 to about 13.6% of the SO ash of said composition is provided by the alkali metal salt. The invention is also directed to lubricating oil compositions comprising the aforementioned compositions and methods of operating a compression ignition engine comprising lubricating said engine with the lubricating oil composition of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein, the terms "hydrocarbon", "hydrocarbyl" or "hydrocarbon based" mean that the group being described has predominantly hydrocarbon character within the context of this invention. These include groups that are purely hydrocarbon in nature, that is, they contain only carbon and hydrogen. They may also include groups containing substituents or atoms which do not alter the predominantly hydrocarbon character of the group. Such substituents may include halo-, alkoxy-, nitro-, etc. These groups also may contain hetero atoms. Suitable hetero atoms will be apparent to those skilled in the art and include, for example, sulfur, nitrogen and oxygen. Therefore, while remaining predominantly hydrocarbon in character within the context of this invention, these groups may contain atoms other than carbon present in a chain or ring otherwise composed of carbon atoms provided that they do not adversely affect reactivity or utility of the process or products of this invention.

In general, no more than about three non-hydrocarbon substituents or hetero atoms, and preferably no more than one, will be present for every 10 carbon atoms in the hydrocarbon or hydrocarbon based groups. Most preferably, the groups are purely hydrocarbon in nature, that is, they are essentially free of atoms other than carbon and _.hydrogen.

Throughout the specification and claims the expression oil soluble or dispersible is used. By oil soluble or dispersible is meant that an amount needed to provide the desired level of activity or performance can be incorporated by being dissolved, dispersed or suspended in an oil of lubricating viscosity. Usually, this means that at least about 0.001% by weight of the material can be incorporated into a lubricating oil. For a further discussion of the terms oil soluble and dispersible, particularly "stably dispersible", see U.S. Patent 4,320,019 which is expressly incorporated herein by reference for relevant teachings in this regard. The expression "lower" is used throughout the specification and claims. As used herein to describe various groups, the expression "lower" is intended to mean groups containing no more than 7 carbon atoms, more often, no more than 4, frequently one or two carbon atoms.

It must be noted that as used in this specification and appended claims, the singular forms also include the plural unless the context clearly dictates otherwise. Thus the singular forms "a", "an", and "the" include the plural; for example "a monomer" includes mixtures of monomers of the same type. As another example the singular form "monomer" is intended to include both singular and plural unless the context clearly indicates otherwise. The Metal Salts

As noted hereinabove, the compositions of this invention comprise alkali and alkaline earth metal salts of at least one acidic organic reagent. These components include those art-recognized metal-containing compositions variously referred to by such names as 'basic', 'superbased' and 'overbased' salts or complexes. The method for their preparation is commonly referred to as 'overbasing'. Also included are the substantially neutral salts and the partially neutralized salts. Partially neutralized salts contain less than the stoichiometric amount of metal needed to neutralize the acid. Usually, partially neutralized salts are those which have been reacted with metal-containing reagent such that at least 50% of the acidic groups of the acidic organic reagent are neutralized.

Neutral salts are those wherein the acid is reacted with substantially stoichiometric amounts of metal.

Neutral or partially neutralized salts are prepared by simply mixing the acid with the desired amount of metal neutralizing reagent, removing by-product water, alcohol, etc.

Generally, the basic or overbased salts are preferred. The overbased (basic) salts contain an excess of the metal cation relative to acid.

These metal containing salts are often referred to as ash containing because upon ignition they leave a metal containing residue referred to in the art as 'ash'. The ash content is determined by heating the material until it is charred, treating the residue with sulfuric acid and evaporating to dryness. The ash content is expressed as % by mass. The procedure for determining sulfated ash is given in ASTM Procedure D-874. Ash content of the metal salts is often used to define the amount of metal present in the metal salts,

The expression 'metal ratio' (frequently abbreviated MR) is often used to define the quantity of metal in these salts. The MR is defined as the ratio of the number of equivalents of metal in the salt relative to the number of equivalents of metal that would be present in a normal salt based upon the usual stoichiometry of the compounds involved. Metal salts used in the compositions of this invention typically have MR ranging from about 0.5, preferably from about 1.5, more generally from about 4 and especially from about 8, up to about 40, often up to about 30 and especially up to about 25. The basic or overbased salts will have metal ratios of up to about 40 and more particularly from about 2 to about 30 or 40. Thus, in a normal calcium carboxylate, the metal ratio is one, and in an overbased carboxylate, the metal ratio is greater than 1. Obviously, if there is present in the material to be overbased more than one compound capable of reacting with the metal, the "metal ratio" of the product will depend upon whether the number of equivalents of metal in the overbased product is compared to the number of equivalents expected to be present for a given single component or a combination of all such components.

Base number is a measure of the amount of basic substances in a composition, for example, an additive or a lubricating oil composition. Relative amounts of basic components can be determined by titration with acids. Typical methods for determining base number are ASTM Procedures D2896 and D-4739. Base number is the amount of perchloric acid expressed in terms of the equivalent number of milligrams of KOH that are required to titrate 1 gram of sample. Total base number (TBN) refers to the base number obtained by titration of all basic components in a composition.

Metal salts having MR up to about 1, that is, partially neutralized salts, are generally prepared by contacting an appropriate acidic reagent with sufficient basic metal or basic metal compound to effect neutralization of part of the acidic reagent. Neutral salts, that is, those having MR = 1, are typically prepared by reacting an appropriate acidic reagent with sufficient basic metal or basic metal compound to effect neutralization of substantially all of the acidic reagent. Overbased salts are prepared by intimately contacting, for a time sufficient to form a stable dispersion, at a temperature between the solidification temperature and the decomposition temperature, at least one acidic material (typically an inorganic acid or lower carboxylic acid, preferably a gaseous material) with a reaction mixture comprising an appropriate acidic reagent susceptible to overbasing, at least one basic metal or basic metal compound, a promoter and usually, a reaction medium.

The temperature at which the acidic material is contacted with the remainder of the reaction mass depends to a large measure upon the promoting agent used. With a phenolic promoter, the temperature usually ranges from about 80°C to 300°C, and preferably from about 100°C to about 200°C. When an alcohol or mercaptan is used as the promoting agent, the temperature usually will not exceed the reflux temperature of the reaction mixture and preferably will not exceed about 100°C. Neutral and partially neutralized salts are prepared over a wide range of temperatures. Often, the neutralization is exothermic and avoiding overheating the reaction mixture is important. Acidic Organic Reagents

Useful acidic organic reagents include sulfur acids, carboxylic acids, phosphorous acids, phenols or mixtures of two or more thereof. Preferred are carboxylic acids and sulfonic acids. While the compositions of this invention may comprise neutral and/or partially neutralized acidic materials, it is preferred that the salts are overbased. Accordingly, the acidic organic reagents employed to prepared the metal salts are those that are susceptible to overbasing.

Acidic organic reagents susceptible to overbasing are preferably carboxylic acids, sulfonic acids or mixtures thereof. The acidic reagents typically are oil soluble or dispersible. They may and usually do have substituent groups, usually aliphatic groups. The substituent groups are often derived from polyalkene. Neutral salts of these acids are also useful as substrates for overbasing.

Throughout this specification and in the appended claims, any reference to acids, such as carboxylic, or sulfonic acids, is intended to include the acid-producing derivatives thereof such as anhydrides, lower alkyl esters, acyl halides, lactones and mixtures thereof unless otherwise specifically stated.

The equivalent weight of the acidic organic compound is its molecular weight divided by the number of acidic groups (i.e., sulfonic acid, carboxy or acidic hydroxy groups) present per molecule. In many cases the acidic organic compound contains a diluent such as oil or unreacted alkylate. Often the acidic organic compound is not a pure single species. In these and in other situations as appropriate, the equivalent weight of the acidic organic compound can be determined by a suitable analytical technique such as acid number (e.g. ASTM procedures D-664 and/or D-974).

The carboxylic acids useful in making the metal salts of the invention may be aliphatic or aromatic, mono- or polycarboxylic acid or acid-producing compounds. These carboxylic acids include lower molecular weight carboxylic acids (e.g., carboxylic acids having up to 22 carbon atoms such as acids having 4 to 22 carbon atoms or tetrapropenyl-substituted succinic anhydride) as well as higher molecular weight carboxylic acids.

The carboxylic acids of this invention are preferably oil-soluble. Usually, in order to provide the desired oil-solubility, the number of carbon atoms in the carboxylic acid should be at least 8, preferably at least 18, more preferably at least

30, and even more preferably at least 50. Generally, these carboxylic acids do not contain more than 400 carbon atoms per molecule.

The lower molecular weight monocarboxylic acids contemplated for use in this invention include saturated and unsaturated acids. Examples of such useful acids include dodecanoic acid, decanoic acid, oleic acid, stearic acid, linoleic acid, tall oil acid, etc. Mixtures of two or more such agents can also be used. An extensive discussion of these acids is found in Kirk-Othmer "Encyclopedia of

Chemical Technology" Third Edition, 1978, John Wiley & Sons New York, pp. 814-

871, to which attention is directed. The monocarboxylic acids include isoaliphatic acids. Such acids often contain a principal chain having from 14 to 20 saturated, aliphatic carbon atoms and at least one but usually no more than four pendant acyclic lower alkyl groups.

Specific examples of such isoaliphatic acids include 10-methyltetradecanoic acid, 3- ethyl-hexadecanoic acid, and 8-methyl-octadecanoic acid. The isoaliphatic acids include mixtures of branch-chain acids prepared by the isomerization of commercial fatty acids (oleic, linoleic or tall oil acids) of, for example, 16 to 20 carbon atoms.

High molecular weight carboxylic acids may also be used in the present invention. These acids have a substituent group derived from a polyalkene. The polyalkene is characterized as containing at least 30 carbon atoms, preferably at least 35, more preferably at least 50, and up to 300 carbon atoms, preferably 200, more preferably 150. In one embodiment, the polyalkene is characterized by an M_n (number average molecular weight) value of at least 500, generally 500 to 5000, preferably 800 to 2500. In another embodiment, M_n varies between 500 to 1200 or 1300. The polyalkenes include homopolymers and interpolymers of polymerizable olefin monomers of 2 to about 16 carbon atoms. The olefins may be monoolefins such as ethylene, propylene, 1-butene, isobutene, and 1-octene; or polyolefinic monomers, preferably diolefinic monomers such 1,3-butadiene and isoprene. Preferably the monomers contain from 2 to 6 carbon atoms, more preferably 3 to 4, more preferably 4. The interpolymers include copolymers, terpolymers, tetrapolymers and the like. Preferably, the polymer is a homopolymer. An example of a preferred polymer is a polybutene, preferably a polybutene in which about 50% of the polymer is derived from isobutylene. The polyalkenes are prepared by conventional procedures.

Illustrative carboxylic acids include lauric acid, palmitic acid, stearic acid, myristic acid, oleic acid, linoleic acid, behenic acid, hexatriacontanoic acid, tetrapropylenyl-substituted glutaric acid, polybutenyl-substituted succinic acid derived from a polybutene (M_n = 200-1500, preferably 300-1000), polypropenyl- substituted succinic acid derived from a polypropene, (M_n = 200-1000, preferably 300-900), octadecyl-substituted adipic acid, chlorostearic acid, 9-methylstearic acid, dichlorostearic acid, stearyl-benzoic acid, eicosanyl-substituted naphthoic acid, dilauryl-decahydronaphthalene carboxylic acid, mixtures of any of these acids, their alkali and alkaline earth metal salts, and/or their anhydrides. A preferred group of aliphatic carboxylic acids includes the saturated and unsaturated higher fatty acids containing from 12 to 30 carbon atoms.

In another embodiment, the carboxylic acids are aromatic carboxylic acids. A group of useful aromatic carboxylic acids is represented by the formula

wherein Ri is an aliphatic hydrocarbyl group of preferably 4 to 400 carbon atoms, a is a number in the range of zero to 4, usually 1 or 2, Ar is an aromatic group, each X is independently sulfur or oxygen, preferably oxygen, b is a number in the range of from 1 to 4, usually 1 or 2, c is a number in the range of zero to 4, usually 1 to 2, with the proviso that the sum of a, b and c does not exceed the number of valences of Ar. Preferably, R_t and a are such that there is an average of at least 8 aliphatic carbon atoms provided by the R₁ groups. Examples of aromatic carboxylic acids include benzoic, phthalic and salicylic acids or anhydrides.

The Ri group is a hydrocarbyl group that is directly bonded to the aromatic group Ar. Ri preferably contains 6 to 80 carbon atoms, preferably 6 to 30 carbon atoms, more preferably 8 to 25 carbon atoms, and advantageously 8 to 15 carbon atoms. Ri groups may be derived from one or more of the above-described polyalkenes. Examples of R_\ groups include butyl, isobutyl, pentyl, octyl, nonyl, dodecyl, 5-chlorohexyl, 4-ethoxypentyl, 3-cyclohexyloctyl, 2,3,5-trimethylheptyl, and substituents derived from polymerized olefins such as polyethylenes, polypropylenes, polyisobutylenes, ethylene-propylene copolymers, chlorinated olefin polymers, oxidized ethylene-propylene copolymers, propylene tetramer and tri(isobutene).

The aromatic group Ar may have the same structure as any of the aromatic groups Ar discussed below. Examples of the aromatic groups that are useful herein include the polyvalent aromatic groups derived from benzene, naphthalene, anthracene, etc., preferably benzene. Specific examples of Ar groups include phenyl groups and naphthyl groups, e.g., methylphenyl, ethoxyphenyl, isopropylphenyl, hydroxyphenyl, dipropoxynaphthyl, etc.

Within this group of aromatic acids, a useful class of carboxylic acids are those of the formula

wherein Ri is defined above, a is a number in the range of from zero to 4, preferably 1 to 2; b is a number in the range of 1 to 4, preferably 1 to 2, c is a number in the range of zero to 4, preferably 1 to 2, and more preferably 1 ; with the proviso that the sum of a, b and c does not exceed 6. Preferably, Ri and a are such that the acid molecules contain at least an average of about 12 aliphatic carbon atoms in the aliphatic hydrocarbon substituents per acid molecule. Preferably, Ar is a phenyl group, b and c are each one and the carboxylic acid is a salicylic acid. The salicylic acids can be aliphatic hydrocarbon-substituted salicylic acids wherein each aliphatic hydrocarbon substituent contains an average of at least 8 carbon atoms per substituent and 1 to 3 substituents per molecule. Overbased salts prepared from such salicylic acids wherein the aliphatic hydrocarbon substituents are derived from the above-described polyalkenes, particularly polymerized lower 1- mono-olefins such as polyethylene, polypropylene, polyisobutylene, ethylene/propylene copolymers and the like and having average carbon contents of 30 to 400 carbon atoms are particularly useful.

In another embodiment, the carboxylic acid is a hydrocarbyl-substituted carboxyalkylene-linked phenol; dihydrocarbyl ester of alkylene dicarboxylic acids, the alkylene group being substituted with a hydroxy group and an additional carboxylic acid group; alkylene-linked polyaromatic molecules, the aromatic moieties whereof comprise at least one hydrocarbyl-substituted phenol and at least one carboxy phenol; and hydrocarbyl-substituted carboxyalkylene-linked phenols. These carboxylic compounds are prepared by reacting a phenolic reagent with a carboxylic reagent of the general formula

1 T wherein R , R and R are independently H or a hydrocarbyl group, R is H or an alkyl group, and x is an integer ranging from 0 to about and reactive equivalents thereof. Compounds of this type are described in several U.S. Patents including numbers 5,281,346; 5,336,278 and 5,356,546.

Unsaturated hydroxycarboxylic compounds prepared by reacting olefinic compounds with this carboxylic compound are also useful. Compounds of this type are described in several U.S. Patents including US Patents 5,696,060; 5,696,067; 5,777,142 and 6,020,500.

In addition to the sulfonic acids useful in making the metal salts of the invention the sulfur containing acids include, sulfinic, sulfenic, partial ester sulfuric, sulfurous and thiosulfuric and thiosulfonic acids.

Generally they are salts of sulfonic acids. The sulfonic acids include the mono- or polynuclear aromatic or cycloaliphatic compounds. The oil-soluble sulfonates can be represented for the most part by one of the following formulae: R₂-T-(SO₃)_a and R₃-(SO₃)_b, wherein T is a cyclic nucleus such as, for example, benzene, naphthalene, anthracene, diphenylene oxide, diphenylene sulfide, petroleum naphthenes, etc.; R₂ is an aliphatic group such as alkyl, alkenyl, alkoxy, alkoxyalkyl, etc.; the group (R )+T contains a total of at least 15 carbon atoms; and R₃ is an aliphatic hydrocarbyl group containing at least 15 carbon atoms. Examples of R₃ are alkyl, alkenyl, alkoxyalkyl, carboalkoxyalkyl, etc. Specific examples of R₃ are groups derived from petrolatum, saturated and unsaturated paraffin wax, and the above-described polyalkenes. The groups T, R₂, and R₃ in the above Formulae can also contain other inorganic or organic substituents in addition to those enumerated above such as, for example, hydroxy, mercapto, halogen, nitro, amino, nitroso, sulfide, disulfide, etc. In the above Formulae, a and b are at least 1.

Illustrative examples of these sulfonic acids include monoeicosanyl- substituted naphthalene sulfonic acids, dodecylbenzene sulfonic acids, didodecylbenzene sulfonic acids, dinonylbenzene sulfonic acids, cetylchlorobenzene sulfonic acids, dilauryl D -naphthalene sulfonic acids, the sulfonic acid derived by the treatment of polybutene having a number average molecular weight (M_n) in the range of 500 to 5000, preferably 800 to 2000, more preferably about 1500 with chlorosulfonic acid, nitronaphthalene sulfonic acid, paraffin wax sulfonic acid, cetyl-cyclopentane, sulfonic acid, lauryl-cyclohexane sulfonic acids, polyethylenyl- substituted sulfonic acids derived from polyethylene (M_n=300-1000, preferably 750), etc. Normally the aliphatic groups will be alkyl and/or alkenyl groups such that the total number of aliphatic carbons is at least 8, preferably at least 12 up to 400 carbon atoms, preferably up to about 250.

Another group of sulfonic acids are mono-, di, and tri-alkylated benzene, toluene, xylene, and naphthalene (including hydrogenated forms thereof) sulfonic acids. Illustrative of synthetically produced alkylated aromatic sulfonic acids are those containing alkyl substituents having from 8 to 30 carbon atoms, preferably 12 to 30 carbon atoms, and advantageously about 24 carbon atoms. Such acids include di-isododecyl-benzene sulfonic acid, cetylchlorobenzene sulfonic acid, di- cetylnaphthalene sulfonic acid, di-laurylphenylether sulfonic acid, diisononylbenzene sulfonic acid, di-isooctadecylbenzene sulfonic acid, stearylnaphthalene sulfonic acid, and the like. Specific examples of oil-soluble sulfonic acids are mahogany sulfonic acids; polyolefin sulfonic acids, e.g., polybutenyl-substituted sulfonic acid, polypropenyl- substituted sulfonic acids derived from polypropene having an M_n=300-1000, preferably 500-700; bright stock sulfonic acids; sulfonic acids derived from lubricating oil fractions having a Saybolt viscosity from 100 seconds at 38°C (100°F) to 200 seconds at 99°C (210°F); petrolatum sulfonic acids; mono- and poly- wax-substituted sulfonic and polysulfonic acids of, e.g., benzene, naphthalene, phenol, diphenyl ether, naphthalene disulfide, etc.; other substituted sulfonic acids such as alkyl benzene sulfonic acids (where the alkyl group has at least 8 carbons), cetylphenol mono-sulfide sulfonic acids, dilauryl- D-naphthyl sulfonic acids, and alkaryl sulfonic acids such as dodecyl benzene "bottoms" sulfonic acids. Dodecyl benzene "bottoms" sulfonic acids are the material left over after the removal of dodecyl benzene sulfonic acids that are used for household detergents. These materials are generally alkylated with higher oligomers. The bottoms may be straight-chain or branched-chain alkylates with a straight-chain dialkylate preferred.

The production of sulfonates from detergent manufactured by-products by reaction with, e.g., SO₃, is well known to those skilled in the art. See, for example, the article "Sulfonates" in Kirk-Othmer "Encyclopedia of Chemical Technology",

Second Edition, Vol. 19, pp. 291 et seq. published by John Wiley & Sons, N.Y. (1969).

The phosphorus-containing acids useful in making the metal salts of the present invention include any phosphorus acids such as phosphoric acid or esters; and thiophosphorus acids or esters, including mono and dithiophosphorus acids or esters. Preferably, the phosphorus acids or esters contain at least one, preferably two, hydrocarby] groups containing from 1 to 50 carbon atoms, typically 1 to 30, preferably 3 to 18, more preferably 4 to 8. The pentavalent phosphorus acids useful in the preparation of the earth metal salts may be an organophosphoric, phosphonic or phosphinic acid, or a thio analog of any of these.

In one embodiment, the phosphorus-containing acids are dithiophosphoric acids which are readily obtainable by the reaction of phosphorus pentasulfide (P₂S₅) and an alcohol or a phenol. The reaction involves mixing at a temperature of about 20°C to about 200°C four moles of alcohol or a phenol with one mole of phosphorus pentasulfide. Hydrogen sulfide is liberated in this reaction. The oxygen-containing analogs of these acids are conveniently prepared by treating the dithioic acid with water or steam which, in effect, replaces one or both of the sulfur atoms with oxygen. In another embodiment, the phosphorus-containing acid is the reaction product of the above-described polyalkene and phosphorus sulfide. Useful phosphorus sulfide-containing sources include phosphorus pentasulfide, phosphorus sesquisulfide, phosphorus heptasulfide and the like.

The reaction of the polyalkene and the phosphorus sulfide generally may occur by simply mixing the two at a temperature above 80°C, preferably between 100°C and 300°C. Generally, the products have a phosphorus content from 0.05% to 10%, preferably from 0.1% to 5%. The relative proportions of the phosphorizing agent to the olefin polymer is generally from 0.1 part to 50 parts of the phosphorizing agent per 100 parts of the olefin polymer. The phenols useful in making the metal salts of the invention can be represented by the formula (Ri)_a-Ar-(OH)t_>, wherein

is defined above; Ar is an aromatic group; a and b are independently numbers of at least one, the sum of a and b being in the range of two up to the number of displaceable hydrogens on the aromatic nucleus or nuclei of Ar. Preferably, a and b are independently numbers in the range of 1 to 4, more preferably 1 to 2. R_\ and a are preferably such that there is an average of at least 8 aliphatic carbon atoms provided by the Ri groups for each phenol compound.

While the term "phenol" is used herein, it is to be understood that this term is not intended to limit the aromatic group of the phenol to benzene. Accordingly, it is to be understood that the aromatic group as represented by "Ar", as well as elsewhere in other formulae in this specification and in the appended claims, can be mononuclear such as a phenyl, a pyridyl, or a thienyl, or polynuclear. The polynuclear groups can be of the fused type wherein an aromatic nucleus is fused at two points to another nucleus such as found in naphthyl, anthranyl, etc. The polynuclear group can also be of the linked type wherein at least two nuclei (either mononuclear or polynuclear) are linked through bridging linkages to each other. These bridging linkages can be chosen from the group consisting of alkylene linkages, ether linkages, keto linkages, sulfide linkages, polysulfide linkages of 2 to 6 sulfur atoms, etc.

The number of aromatic nuclei, fused, linked or both, in Ar can play a role in determining the integer values of a and b. For example, when Ar contains a single aromatic nucleus, the sum of a and b is from 2 to 6. When Ar contains two aromatic nuclei, the sum of a and b is from 2 to 10. With a tri-nuclear Ar moiety, the sum of a and b is from 2 to 15. The value for the sum of a and b is limited by the fact that it cannot exceed the total number of displaceable hydrogens on the aromatic nucleus or nuclei of Ar. Preferred are phenols containing at least one alkyl substituent containing about 3-100 and especially about 6-50 carbon atoms, such as heptylphenol, octylphenol, dodecylphenol, tetrapropene-alkylated phenol, octadecylphenol and polybutenylphenols. Phenols containing more than one alkyl substituent may also be used, but the monoalkylphenols are preferred because of their availability and ease of production.

Also useful are condensation products of the above-described phenols with at least one lower aldehyde or ketone, the term "lower" denoting aldehydes and ketones containing not more than 7 carbon atoms. Suitable aldehydes include formaldehyde, acetaldehyde, propionaldehyde, the butyraldehydes, the valeraldehydes and benzaldehyde. Also suitable are aldehyde-yielding reagents such as paraformaldehyde, trioxane, methylol, Methyl Formcel and paraldehyde. Formaldehyde and the formaldehyde-yielding reagents are especially preferred. Promoters

Promoters are chemicals employed to facilitate incorporation of the metal into the basic metal composition. A discussion of suitable promoters is found in U.S Patents 2,777,874; 2,695,910; 2,616,904; 4,326,972 and 5,449,470. These include the alcoholic and phenolic promoters. Alcoholic promoters include the mono and polyhydroxy compounds such as methanol. ethanol, isopropanol and octanol, ethylene glycol, 1,3-propane diol, and others. Phenolic promoters include a variety of hydroxy substituted benzenes and naphthalenes, especially alkylated compounds, for example, heptylphenol, octyl phenol and nonyl phenol. Mixtures are sometimes used. It is often preferred to use, as an additional promoter, a carboxylic acid containing about 1-100 carbon atoms or an alkali metal, alkaline earth metal, zinc or lead salt thereof. Especially preferred in this regard are the lower alkyl monocarboxylic acids including formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid and the like. The amount of such acid or salt used is generally about 0.002-0.2 equivalent per equivalent of metal base used for formation of the basic salt. The Acidic Material

The acidic material employed in the overbasing process are not the same as the acidic organic reagents subjected to overbasing. The acidic material may be a liquid, such as acetic, nitric, phosphoric or sulfuric acid. Inorganic acidic in solid or gaseous phase may be used. These include such materials as HC1, SO₂, SO₃, CO₂, H₂S or P₂O₅, preferably CO₂.

A commonly employed method for preparing the basic (overbased) salts comprises heating a mineral oil solution of the acid with a stoichiometric excess of a metal neutralizing agent, e.g., a metal oxide, hydroxide, carbonate, bicarbonate, sulfide, etc., at temperatures above about 50° C. In addition, various promoters described hereinabove may be used in the neutralizing process to aid in the incorporation of the large excess of metal. A particularly effective process for preparing the basic salts comprises mixing the acid with an excess of the basic alkaline earth metal in the presence of the phenolic promoter and a small amount of water and carbonating the mixture at an elevated temperature, e.g., 60°C to about 200° C.

In one embodiment, the oils of the invention may contain at least one neutral or basic metal salt of an alkylphenol sulfide. The oils may contain from about 0 to about 2 or 3% of said phenol sulfides. More often, the oil may contain from about 0.01 to about 2% by weight of the basic salts of phenol sulfides. The term "basic" is used herein the same way in which it was used in the definition of other components above, that is, it refers to salts having a metal ratio of greater than 1. The neutral and basic salts of phenol sulfides are detergents and antioxidants in the oil compositions. The alkylphenols from which the sulfide salts are prepared generally comprise phenols containing hydrocarbon substituents with at least about 6 carbon atoms; the substituents may contain up to about 7000 aliphatic carbon atoms. Also included are substantially hydrocarbon substituents, as defined hereinabove. The preferred hydrocarbon substituents are derived from the polymerization of olefins such as ethylene, propene, 1-butene, isobutene, 1-hexene, 1-octene, 2-methyl-l- heptene, 2-butene, 2-pentene, 3-pentene and 4-octene. The hydrocarbon substituent may be introduced onto the phenol by mixing the hydrocarbon and the phenol at a temperature of about 50°-200°C. in the presence of a suitable catalyst such as aluminum trichloride, boron trifluoride, zinc chloride or the like. The substituent can also be introduced by other alkylation processes known in the art. The term "alkylphenol sulfides" is meant to include di-

(alkylphenol)monosulfides, disulfides, polysulfides, and other products obtained by the reaction of the alkylphenol with sulfur monochloride, sulfur dichloride or elemental sulfur. The molar ratio of the phenol to the sulfur compound can be from about 1:0.5 to about 1:1.5, or higher. For example, phenol sulfides are readily obtained by mixing, at a temperature above about 60°C, one mole of an alkylphenol and 0.5-1.5 moles of sulfur dichloride. The reaction mixture is usually maintained at about 100°C. for about 2-5 hours, after which time the resulting sulfide is dried and filtered. When elemental sulfur is used, temperatures of about 200°C or higher are sometimes desirable. It is also desirable that the drying operation be conducted under nitrogen or a similar inert gas.

The basic salts of phenol sulfides are conveniently prepared by reacting the phenol sulfide with a metal base, typically in the presence of a promoter. Temperatures and reaction conditions are similar for the preparation of the basic products. Preferably, the basic salt is treated with carbon dioxide after it has been formed.

It is often preferred to use, as an additional promoter, a carboxylic acid containing about 1-100 carbon atoms or an alkali metal, alkaline earth metal, zinc or lead salt thereof. Especially preferred in this regard are the lower alkyl monocarboxylic acids including formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid and the like. The amount of such acid or salt used is generally about 0.002-0.2 equivalent per equivalent of metal base used for formation of the basic salt. In an alternative method for preparation of these basic sulfurized alkylphenol salts, the alkylphenol is reacted simultaneously with sulfur and the metal base. The reaction is usually carried out at a temperature of at least about 150°C, preferably about 150°-200°C. It is frequently convenient to use as a solvent a compound which boils in this range, preferably a mono-(lower alkyl) ether of a polyethylene glycol such as diethylene glycol. The methyl and ethyl ethers of diethylene glycol, which are respectively sold under the trade names "Methyl Carbitol" and "Carbitol", are especially useful for this purpose.

Suitable basic alkyl phenol sulfides are disclosed, for example, in U.S. Patent Nos. 3,372,116 and 3,410,798, which are hereby incorporated by reference. Alkali Metal Salts

Alkali metal salts useful in the compositions of this invention include principally lithium, sodium and potassium salts with lithium and sodium being preferred and lithium being particularly preferred. A general description of some of the alkali metal salts useful in this invention is contained in U.S. Patent 4,326,972, which patent is hereby incorporated herein by reference for its disclosure of alkali metal salts and methods of preparing such salts.

Alkali metals present in the alkali metal salts of this invention are sodium, potassium and lithium. The alkali metal salts are usually prepared using basic alkali metal compounds, especially the oxides and hydroxides, alkoxides, especially those containing no more than 7 carbon atoms, hydrides, amides, carbonates, borates, nitrates and others. Alkaline Earth Metal Salts

As mentioned above, the acidic organic compound from which the alkaline earth metal salt is prepared may be at least one sulfur acid, carboxylic acid, phosphorus acid, or phenol or mixtures thereof. Some of these acidic organic compounds (sulfonic and carboxylic acids) previously have been described above with respect to the preparation of the alkali metal salts, and all of the acidic organic compounds useful for preparing alkali metal salts can be utilized in the preparation of the alkaline earth metal salts by techniques known in the art.

Calcium, magnesium, barium and strontium are the preferred alkaline earth metals. Salts containing a mixture of ions of two or more of these alkaline earth metals can be used. Calcium and magnesium are especially preferred. The alkaline earth metal salts are usually prepared using basic alkaline earth metal compounds, especially the oxides and hydroxides, alkoxides, especially those containing no more than 7 carbon atoms, hydrides, amides, carbonates, borates, nitrates and others. The alkaline earth salts are typically prepared by reacting one or more of the desired alkaline earth metal reactants with an appropriate acid, with carbonation until the direct base number ranges from 0 to about 5. Mixed Alkali/ Alkaline Earth Metal Salts

The compositions of this invention contain a mixture of alkali and alkaline earth metal salts. In one embodiment, these can be provided by incorporating individually prepared alkali and alkaline earth metal salts such as those illustrated hereinabove. In another embodiment, the mixed salts can be provided from a single composition containing both alkali and alkaline earth metal salts. These can be prepared by a number of different methods, for example, by reacting, with carbonation, a mixture of a calcium sulfonate, polyolefin substituted succinic anhydride, and substituted phenol with sodium hydroxide, carbonating until the direct base number ranges from 0 to about 5. Other Additives

Additive concentrates and lubricating oil compositions of this invention may contain other additives. The use of such additives is optional and the presence thereof in the compositions of this invention will depend on the particular use and level of performance required. Thus the other additive may be included or excluded.

One or more zinc salts of dithiophosphoric acids other than those described herein as component (C) may be present in a minor amount to provide additional extreme pressure, anti-wear and anti-oxidancy performance.

Other additives that may optionally be used in the lubricating oils of this invention include, for example, auxiliary ash containing detergents, ashless dispersants, viscosity improvers, oxidation inhibitors, corrosion inhibitors, pour point depressants, extreme pressure agents, anti-wear agents, color stabilizers, friction modifiers, and anti-foam agents.

The above-illustrated other additives are well known in the art and are described in numerous patents and publications. They may each be present in lubricating compositions at a concentration of as little as 0.001% by weight, usually ranging from about 0.01% to about 20% by weight. In most instances, when used, each contributes from about 0.1% to about 10% by weight, more often up to about 5% by weight. Additive Concentrates

Lubricating oil compositions of this invention may be prepared by directly adding each ingredient to the oil of lubricating viscosity. Preferably, however, they are usually supplied as an additive concentrate wherein the additives, usually a mixture of two or more thereof, are diluted with a substantially inert, normally liquid organic diluent such as mineral oil, a synthetic oil such as a polyalphaolefin, naphtha, benzene, toluene or xylene. The additive concentrates usually contain at least about 20% by weight of additives, often as much as 80% by weight. Additive concentrates are prepared by mixing together the desired components, often at elevated temperatures, usually less than 150°C, often no more than about 130°C, frequently no more than about 100°C. Oil of Lubricating Viscosity

The lubricating compositions of this invention employ an oil of lubricating viscosity, including natural or synthetic lubricating oils and mixtures thereof. Mixtures of mineral oil and synthetic oils, particularly polyalphaolefin oils and polyester oils, are often used.

Natural oils include animal oils and vegetable oils (e.g. castor oil, lard oil and other vegetable acid esters) as well as mineral lubricating oils such as liquid petroleum oils and solvent-treated or acid treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Hydrotreated or hydrocracked oils are included within the scope of useful oils of lubricating viscosity.

Oils of lubricating viscosity derived from coal or shale are also useful. Synthetic lubricating oils include hydrocarbon oils and halosubstituted hydrocarbon oils such as polymerized and interpolymerized olefins, etc. and mixtures thereof, alkylbenzenes, polyphenyl, (e.g., biphenyls, terphenyls, alkylated polyphenyls, etc.), alkylated diphenyl ethers and alkylated diphenyl sulfides and their derivatives, analogs and homologues thereof and the like. Alkylene oxide polymers and interpolymers and derivatives thereof, and those where terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute other classes of known synthetic lubricating oils that can be used.

Another suitable class of synthetic lubricating oils that can be used comprises the esters of dicarboxylic acids and those made from C₅ to C₁₂ monocarboxylic acids and polyols or polyether polyols.

Other synthetic lubricating oils include liquid esters of phosphorus-containing acids, polymeric tetrahydrofurans, alkylated diphenyloxides and the like.

Unrefined, refined and rerefined oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove can used in the compositions of the present invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Such rerefined oils often are additionally processed by techniques directed to removal of spent additives and oil breakdown products.

Specific examples of the above-described oils of lubricating viscosity are given in Chamberlin JJI, U.S. 4,326,972 and European Patent Publication 107,282, both of which are hereby incorporated herein by reference for relevant disclosures contained therein.

A basic, brief description of lubricant base oils appears in an article by D.V. Brock, "Lubrication Engineering", Volume 43, pages 184-5, March, 1987, which article is expressly incorporated by reference for relevant disclosures contained therein.

The following Examples illustrate lubricating oil compositions of this invention. Unless indicated otherwise, all parts are parts by weight and, unless otherwise indicated, are on an oil or diluent-free basis. Baseline Lubricant I A lubricating oil composition containing only alkaline earth metal detergents is prepared by combining, in sufficient oil of lubricating viscosity to prepare 100 parts of lubricant, 8.5 parts of a 9% in mineral oil solution of an ethylene-propylene- dicyclopentadiene terpolymer, 0.08 parts of a styrene-maleate ester copolymer neutralized with aminopropylmorpholine and 11.86 parts of an additive concentrate containing 29.3 parts of a polyisobutylene (M_n ~ 950) substituted succinic anhydride reacted with an ethylene polyamine, 9.86 parts of a zinc salt of a mixed isopropyl-2-ethylhexyl dithiophosphate, 2.12 parts of di-(nonylyphenyl) amine, 10.2 parts of a 45% in mineral oil solution of calcium overbased (MR 1.1, TBN =90, %Ca = 3.2, SO ash = 11.0%) sulfurized dodecylphenol, 22.34 parts of a 53% in mineral oil solution of calcium overbased (MR 2.8, TBN = 85, %Ca = 4.78, SO ash = 16.2%) primary, straight chain mono-alkylbenzene sulfonic acid (MW 480), 4.22 parts of 58% in mineral oil solution of Mg overbased (MR 14.7, TBN = 400, %Mg = 9.4, SO ash = 47)) primary mono-alkylbenzene sulfonic acid (MW ~ 480), 0.08 parts of a kerosene solution of a silicone antifoam agent and sufficient oil to make 100 parts of concentrate. Lubricant 1 A lubricating oil composition is prepared as in Baseline Lubricant I replacing

11.86 parts of the additive concentrate of baseline lubricant I with 11.88 parts of an additive concentrate substantially identical to that used in the baseline except 4.08 parts of the calcium overbased (MR 2.8) sulfonic acid is replaced with 4.21 parts of a 59.3% in mineral oil solution of lithium overbased (MR ~ 3, TBN = 101, 14.7% Li SO ash)) primary, straight chain mono-alkylbenzene sulfonic acid (MW 480). The ash level of the lubricating oil composition remains constant. Lubricant 2

A lubricating oil composition is prepared as in Baseline Lubricant I replacing 11.86 parts of the additive concentrate of the baseline with 11.7 parts of an additive concentrate substantially identical to that used in the baseline except 5.34 parts of the calcium overbased (MR 2.8) sulfonic acid is replaced with 4.28 parts of a 58.8% in mineral oil solution of a mixed calcium/sodium overbased (TBN = 129, %Na = 4.33, %Ca = 2.0) primary, branched chain mono alkyl benzene sulfonic acid (MW = 500). The ash level of the lubricating oil composition remains constant. Lubricant 3

A lubricating oil composition is prepared as in Baseline Lubricant I replacing 11.86 parts of the additive concentrate of the baseline with 11.94 parts of an additive concentrate substantially identical to that used in the baseline except 3.83 parts of the calcium overbased (MR 2.8) sulfonate and 1.7 parts of the overbased (MR 14.7) Mg sulfonate are replaced with 1.01 parts of a 64% in mineral oil solution of sodium overbased (MR 23, TBN = 448, %Na = 19.45, SO₄ ash = 60%) primary, straight chain mono-alkylbenzene sulfonic acid (MW 480) and 5.03 parts of a 54% in mineral oil solution of a Mg overbased (MR 2:8, TBN = 100, % Mg = 3.45, SO₄ ash = 17) primary, mono-alkylbenzene sulfonic acid (MW ~ 480). The ash level of the lubricating oil composition remains constant. Baseline Lubricant II A lubricating oil composition containing only calcium metal detergents is prepared by combining, in sufficient oil of lubricating viscosity to prepare 100 parts of lubricant, 8.5 parts of a 9.5 % in mineral oil solution of an ethylene-propylene copolymer, 0.2 . parts of a 65% in oil solution of a polymethacrylate copolymer, and

12.9 parts of an additive concentrate containing 53.3 parts of a polyisobutylene (M_n ~ 950) substituted succinic anhydride reacted with an ethylene polyamine, 21.6 parts of calcium overbased (MR 2.8, TBN = 85, %Ca = 4.78, SO₄ ash = 16.2%) primary, straight chain mono-alkylbenzene sulfonic acid (MW 480), 1.6 parts of a 53% in mineral oil solution of a Ca overbased (MR 11, TBN = 300, %Ca = 12, SO4 ash = 40.7) mixed primary and branched chain monoalkyl benzene sulfonic acid (MW ~ 480), 10.8 parts of a 59% in mineral oil solution of a Ca overbased (MR 2.3, TBN = 200, %Ca = 7.2, SO₄ ash = 24.5) sulfurized dodecylphenol, 6.66 parts of a zinc salt of a mixed isopropyl-methyl amyl dithiophosphate, 4.6 parts of di-(nonyl phenyl) amine, 0.08 parts of a kerosene solution of a silicone antifoam agent and sufficient mineral oil diluent to prepare 100 parts of additive concentrate. Lubricant 4

A lubricating oil composition is prepared as in Baseline Lubricant II replacing 12.98 parts of the additive concentrate of the baseline with 12.99 parts of an additive concentrate substantially identical to that used in the baseline replacing 5.9 parts of the Ca overbased (MR 2.8) sulfonate with 0.9 parts additional Ca overbased (MR 11) sulfonate and 4.7 parts of a 60% in mineral oil solution of a lithium overbased (MR ~ 3, TBN ~ 90„ 13% Li₂SO ash)) primary, straight chain mono-alkylbenzene sulfonic acid (MW 480). The ash level of the lubricating oil composition remains constant.

Testing

The Caterpillar IK test procedure has been correlated with direct injection engines used in heavy-duty service, particularly in respect of piston and ring groove deposits. The test procedure is described in ASTM Research Report RR:D02 1273, "Caterpillar IK Test ASTM Research Report."

Compared to the baseline lubricants, lubricating oil compositions of this invention display improved performance employing the Caterpillar IK engine test and on panel coker deposit screen tests

It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. For instance, metal ions (of, e.g., a detergent) can migrate to other acidic sites of other molecules. The products formed thereby, including the products formed upon employing the composition of the present invention in its intended use, may not susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses the composition prepared by admixing the components described above. Each of the documents referred to above is incorporated herein by reference.

Except in the examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word "about". Unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade. However, the amount of each chemical component is presented exclusive of any solvent or diluent oil which may be customarily present in the commercial material, unless otherwise indicated. It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined. As used herein, the expression "consisting essentially of" permits the inclusion of substances which do not materially affect the basic and novel characteristics of the composition under consideration.

While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications that fall within the scope of the appended claims.

Claims

What is claimed is

1. A composition comprising alkali and alkaline earth metal salts of at least one acidic organic reagent wherein from about 4.0 to about 10.3% of the TBN of said composition is provided by the alkali metal salt.

2. A composition comprising alkali and alkaline earth metal salts of at least one acidic organic reagent wherein from about 5.0 to about 13.6% of the SO ash of said composition is provided by the alkali metal salt.

3. The composition of claim 1 wherein the acidic organic reagent is at least one of alkyl or alkenyl substituted sulfur acids, phosphorus acids, carboxylic acids, phenols and mixtures thereof.

4. The composition of claim 2 wherein the acidic organic reagent is at least one of alkyl or alkenyl substituted sulfur acids, phosphorus acids, carboxylic acids, phenols and mixtures thereof.

5. The composition of claim 1 wherein each metal salt comprises at least one of alkyl or alkenyl substituted phenates, sulfurized phenates, aromatic sulfonates, salicylates, sulfurized salicylates, carboxylates and phosphates.

6. The composition of claim 2 wherein each metal salt comprises at least one of alkyl or alkenyl substituted phenates, sulfurized phenates, aromatic sulfonates, salicylates, sulfurized salicylates, carboxylates and phosphates.

7. A composition comprising alkali and alkaline earth metal salts of at least one acidic organic reagent wherein from about 4.0 to about 10.3% of the TBN of said composition and from about 5.0 to about 13.6% of the SO ash of said composition is provided by the alkali metal salt.

8. The composition of claim 7 wherein the alkali metal is at least one of lithium and sodium and the alkaline earth metal is at least one of calcium and magnesium.

9. The composition of claim 8 wherein the alkaline earth metal salt is a calcium salt.

10. The composition of claim 7 wherein the alkali metal salt is at least one of a carboxylate and sulfonate and the alkaline earth metal salt comprises calcium sulfurized phenates and sulfonates and magnesium sulfonates.

11 The composition of claim 7 wherein the alkali metal is present as a mixed alkali-alkaline earth metal salt.

12. The composition of claim 11 wherein the mixed salt is a substantially sulfur- free alkyl phenate or derivative thereof.

13. The composition of claim 11 wherein the mixed salt is a sulfonate.

14. The composition of claim 8 wherein each metal salt has metal ratio ranging from about 0.5 to about 30.

15. The composition of claim 14 wherein each metal salt is an overbased metal salt having metal ratio ranging from about 1.5 to about 30.

16. A lubricating oil composition having TBN ranging from about 6.0 to about 11.3 comprising an oil of lubricating viscosity and wherein from about 4.0 to about 10.3% of the TBN is provided by the composition of claim 1.

17. A lubricating oil composition having SO ash content ranging from about 0.70 to about 1.35 comprising an oil of lubricating viscosity and wherein from about 5.0 to about 13.6% of the SO ash is provided by the composition of claim 2.

18. A lubricating oil composition having TBN ranging from about 6.0 to about 11.3 and SO ash content ranging from about 0.70 to about 1.35, comprising an oil of lubricating viscosity and wherein from about 4.0 to about 10.3% of the TBN and from about 5.0 to about 13.6% of the SO₄ ash is provided by the composition of claim 7.

19. A method of operating a compression ignition engine comprising lubricating said engine with the lubricating oil composition of claim 16.

20. A method of operating a compression ignition engine comprising lubricating said engine with the lubricating oil composition of claim 17.

21. A method of operating a compression ignition engine comprising lubricating said engine with the lubricating oil composition of claim 18.