US3671430A - High alkalinity additives for lubricating oil compositions - Google Patents

Abstract

An alkaline earth metal sulfonate of high alkalinity is prepared by reacting an alkaline earth metal base, e.g. calcium hydroxide, with carbon dioxide in the presence of the metal sulfonate and an alkaline earth metal phenate, there also being present a polar solvent such as benzyl alcohol or tetrahydrofurfuryl alcohol, as well as free phenol in an amount over and above the stoichiometric quantity necessary to form metal phenate by reaction with the metal base. At the end of the reaction the solvent and free phenol are removed from the product by distillation. Preformed metal phenate can be used at the beginning of the reaction or the metal phenate can be formed in situ, starting with free phenol. Also, in place of metal sulfonate, free sulfonic acid can be used initially, with sufficient metal base to convert it to metal sulfonate. The attainment of total base numbers of 400 or more is possible by use of a second dispersant along with the metal sulfonate. This second dispersant, which is used with the sulfonate in the proportion of 0.1 to 1 part per part of sulfonate, can be a thioacid of phosphorus, or metal salt thereof, obtained by reaction of a sulfide of phosphorus on a hydrocarbon; an alkyl phenol or alkyl phenol sulfide, or metal salt thereof; or a monocarboxylic or polycarboxylic acid or anhydride, or metal salt thereof, characterized by a long chain hydrocarbon group of from about 20 to 200 carbon atoms, as for example, a polyisobutenyl succinic acid.

Description

United States Patent Corringer [451 June 20, 1972 [54] HIGH ALKALINITY ADDITIVES FOR LUBRICATING OIL COMPOSITIONS [72] lnventor: Jean Col-ringer, Mont-Saint-Aignan,

France [73] Assignee: Esso Research and Engineering Company [22] Filed: Jan. 19, 1971 [21] Appl. No.: 107,846

Related U.S. Application Data [63] Continuation-in-part of Ser. No. 44,632, June 8, 1970, abandoned, which is a continuation of Ser. No. 625,307, March 23, 1967, abandoned.

[30] Foreign Application Priority Data Jan. 21, 1970 France ..7002168 [52] U.S. Cl ..252/32.7 E, 252/333, 252/334, 252/33 [51] Int. Cl. ..Cl0m 1/40, ClOm H48 [58] Field ofSearch .252/32.7 R,33, 33.3, 33.4, 252/327 E [561 References Cited UNITED STATES PATENTS 2,616,924 11/1952 Asseft'et a1. ..252/33 X 2,695,910 11/1954 Asseffet al. ..252/33 X 3,312,618 4/1967 Le Suer et al ..252/33 3,350,308 lO/1967 McMillen ..252/33 Primary Examiner-Daniel E. Wyman Assistant ExaminerW. J. Shine Attomey-Pearlman & Schlager and Byron O. Dimmick [57] ABSTRACT An alkaline earth metal sulfonate of high alkalinity is prepared by reacting an alkaline earth metal base, e.g. calcium hydroxide, with carbon dioxide in the presence of the metal sulfonate and an alkaline earth metal phenate, there also being present a polar solvent such as benzyl alcohol or tetrahydrofurfuryl alcohol, as well as free phenol in an amount over and above the stoichiometric quantity necessary to form metal phenate by reaction with the metal base. At the end of the reaction the solvent and free phenol are removed from the product by distillation. Preformed metal phenate can be used at the beginning of the reaction or the metal phenate can be formed in situ, starting with free phenol. Also, in place of metal sulfonate, free sulfonic acid can be used initially, with sufficient metal base to convert it to metal sulfonate. The attainment of total base numbers of 400 or more is possible by use of a second dispersant along with the metal sulfonate. This second dispersant, which is used with the sulfonate in the proportion of 0.1 to 1 part per part of sulfonate, can be a thioacid of phosphorus, or metal salt thereof, obtained by reaction of a sulfide of phosphorus on a hydrocarbon; an alkyl phenol or alkyl phenol sulfide, or metal salt thereof; or a monocarboxylic or polycarboxylic acid or anhydride, or metal salt thereof, characterized by a long chain hydrocarbon group of from about 20 to 200 carbon atoms, as for example, a polyisobutenyl succinic acid.

18 Claims, No Drawings HIGH ALKALINITY ADDITIVES FOR LUBRICATING OIL COMPOSITIONS REFERENCE TO RELATED APPLICATIONS cation Ser. No. 625,30l, filed Mar. 23, 1967, and now abancloned.

BACKGROUND OF THE INVENTION This invention concerns an improved process for making an overbased alkaline earth metal sulfonate, an improved product, and an improved lubricant containing the product. More particularly, the invention concerns the preparation of a sulfonate of high alkalinity, i.e. an overbased sulfonate wherein a colloidal dispersion of calcium carbonate is formed by the carefully controlled reaction of a calcium base and carbon dioxide in the presence of said sulfonate and a promoter.

Overbased metal sulfonates are well known in the art as desirable additives for lubricating oils. See for example, U.S. Pats. Nos. 2,839,470; 2,856,360; 3,057,896; 3,429,8ll, etc. Their desirable functions include suspension of sludge, prevention of deposit formation, and imparting of rust inhibiting properties to lubricants and other oil compositions. Briefly, an overbased sulfonate is one containing excess metal over that required for complete neutralization of the sulfonic acid. Usually, overbasing is accomplished by adding excess metal base, e.g. lime, to the sulfonate or sulfonic acid, and then neutralizing the excess metal base with carbon dioxide. The best theory is that the colloidal dispersion of calcium carbonate or other metal carbonate that is thereby formed is stabilized by the sulfonate, which forms a protective covering around the carbonate to thereby prevent undesirable agglomeration of the colloidal-size carbonate crystals. Otherwise, this agglomeration can lead to precipitation of the carbonate, particularly when making overbased sulfonates of high base number. Frequently, in the overbasing of sulfonates, the excess metal base is added in the presence of a promoter.

DESCRIPTION OF INVENTION In accordance with the present invention an oil-soluble alkaline earth metal sulfonate of high alkalinity is prepared by a process in which a mixture of 1) an alkaline earth metal base and a stoichiometric excess of phenol; or a mixture of an alkaline earth metal phenate and phenol, (2) a polar solvent, (3) an alkaline earth metal sulfonate or a purified sulfonic acid is reacted with carbon dioxide and thereafter the reaction mixture is distilled, thereby removing and recovering phenol and solvent, and the product is filtered. Stated more succinctly, a colloidal dispersion of calcium carbonate is prepared by reaction of carbon dioxide with a calcium base in the presence of calcium hydrocarbon sulfonate, in the presence of an amount of phenol in excess of the stoichiometric amount of total calcium base present, and in the presence of a polar solvent.

The invention is particularly applicable to the preparation of a high base number calcium hydrocarbon sulfonate.

The starting sulfonates used in the present invention may be either neutral sulfonates, i.e. where the sulfonic acid is neutralized with an equal molar equivalent amount of metal base, or they may have been overbased to a mild degree, e.g. to a base number of say 30 or 40. One may also start with a sulfonic acid in which case additional lime will be used to convert the acid to the salt. If sulfonic acids are used as starting materials they should be purified, i.e., they should contain no more than about 0.2 wt. percent of sulfuric acid.

Sulfonic acids used in this art are classified generally as either petroleum sulfonic acids or synthetic sulfonic acids. Petroleum sulfonic acids are produced by treating petroleum fractions, usually lubricating oil distillate fractions, the socalled white oil distillates, or other petroleum fractions, e.g.

petrolatum, with suitable sulfonating agents, including sulfur tiioxide, concentrated sulfuric acid and fuming sulfuric acid. Synthetic sulfonic acids are prepared by treating relatively pure synthetic hydrocarbons in the same manner.

Synthetic sulfonic acids are usually prepared by sulfonating alkylated aromatic hydrocarbons having alkyl groups totalling about 10 to 33 carbon atoms, e.g. sulfonated products of alkylated aromatics, such as benzene, toluene, xylene, and naphthalene, alkylated with wax hydrocarbons, olefins, olefin polymers, etc. Typically, benzene is alkylated with a polymer of propylene or butylene, e.g. butylene trimer, and then sulfonated. The natural or synthetic sulfonic acids used in this invention include alkane sulfonic acids, aromatic sulfonic acids, alkaryl sulfonic acids and aralkyl sulfonic acids. Specific details of the preparation of sulfonic acids need not be given here because the sulfonation of hydrocarbons is well known to the art.

While the principles of this invention can be applied to the overbasing of salts of petroleum sulfonic acids or synthetic hydrocarbon sulfonic acids that have molecular weights ranging between about 400 and about 1,200, they are more usually applicable to those desired from sulfonic acids having molecular weights in the range of about 400 to about 600 and in some instances preferably about 450 to 550.

It is usually preferable to employ the sulfonate or sulfonic acid in the form of a concentrate of from 30 to 50 weight percent in a light mineral oil. When a sulfonic acid solution or concentrate is used, it may be an advantage to add to parts of that acid 0.5 to 1 part of an alkaline earth chloride or 1 or 5 parts of an alkaline earth nitrate, in order to avoid the formation of gels.

This invention is particularly a plicable to the overbasin g of calcium sulfonates and is especially advantageous for preparing an overbased calcium sulfonate having a total base number of at least 250-300. Base number is defined in numerical terms equivalent to milligrams of KOH per gram of the material. Base number is also frequently referred to as alkalinity index. The importance of overbasing a sulfonate is an economic one; the higher the base number the more benefit one obtains per unit weight of sulfonate. There are a number of prior art processes that are suitable for the preparation of overbased sulfonates having base numbers as high as about 200 but it is usually difficult to prepare products having total base number in excess of about 225 and higher. It is especially desirable to prepare those having at least 300 total base number.

In one aspect of this invention, overbased calcium hydrocarbon sulfonates of total base numbers of about 300 to about 320 are obtained when using the metal sulfonate as the dispersant. In an improved modification of the invention total base numbers of 400 or greater are obtained by using as the dispersant a combination of metal hydrocarbon sulfonate and a second dispersant, selected from the class consisting of an organic thioacid of phosphorus, an alkyl phenol, an alkyl phenol sulfide, an alkenyl monocarboxylic acid of about 300 to 2,000 molecular weight in the alkenyl group, an alkenyl dicarboxylic acid of about 300 to 2,000 molecular weight in the alkenyl group, or an alkaline earth metal salt of any of the aforementioned compounds.

In conducting the process of this invention it is ordinarily preferred to first form the phenate of an alkaline earth metal by causing the oxide or hydroxide of that metal to react with an excess of phenol dissolved in a suitable solvent, then, this phenate being dispersed in a medium containing, besides the same solvent and the phenol in excess, an alkaline earth metal sulfonate, it is treated with carbon dioxide gas, then finally the liberated phenol and the solvent are distilled and recovered for re-use in a subsequent operation. Dispersion of the alkaline earth metal phenate in the sulfonate can be efiected in any manner, either by preparing a dispersion separately by introducing alkaline earth base into a mixture of solvent and phenol and injecting this dispersion into the sulfonate, or by mixing sulfonate, solvent and phenol and treating the whole with the alkaline earth metal base. Although this operation can be performed in the cold, a temperature in the region of 80 C. or so is helpful for obtaining a good dispersion. The preferred alkaline earth metal base is one of calcium; e.g. lime of standard quality, quick or slaked.

The solvenm that can be used are polar solvents such as alcohols, ethers, chlorinated hydrocarbons, or nitrohydrocarbons, etc. Solvents which have a boiling point between 160 and 220 C. are preferable for, besides the part they play as dispersing agent for the phenate, they allow the easier elimination of the phenol by distillation. Preferred examples are benzyl alcohol andtetrahydrofurfuryl alcohol, but alternative solvents are cyclohexanol and methylcyclohexanol. Aliphatic alcohols and glycols are not so suitable.

A suitable proportion of solvent is from 80 to 150 percent, or better still, from 100 to 120 percent based on the weight of the sulfonate or sulfonic acid, e.g. a 40 percent by weight sulfonate solution in lubricating oil. The proposition of phenol in relation to the alkaline earth metal base should be at least stoichiometric; an excess of 10 percent, i.e. the introduction of about 2.2 mols phenol to 1 mol base is preferable.

When using purified sulfonic acids, either entirely instead of or partly instead of sulfonates, the suspension obtained with the base, the phenol and solvent can be injected into an oil solution of sulfonic acids, or else the oil solution of sulfonic acids can be mixed with phenol, the polar solvent and the medium thus obtained being treated with alkaline earth metal base. a

Water is present in the reaction mixture and comes in particular from the reaction of the base or from the slaked lime when the latter is used. However, water can be added to the reaction mixture to further the reaction and the water is easily eliminated by final distilling.

The carbon dioxide gas serves on the one hand to displace the phenol and to supply colloidal alkaline earth metal carbonate; on the other hand it helps to remove the phenol and the solvent by serving as a stripping gas. The quantity of Co, to be used should, therefore, exceed the theoretical quantity of one mol of C per mol of alkaline earth metal base or phenate used; in practice two or four times the theoretical quantity is preferable.

The reaction according to the invention can be carried out in several stages, two for preference. For instance, it is possible to use half the required quantity of solvent, phenol and base and treat with carbon dioxide gas to displace the phenol; then, after this treatment, the remainder of the quantity of base is added to reconstitute phenate and further treatment by carbon dioxide gas takes place; the solvent and phenol are thus used twice.

In order to eliminate'the last traces of phenol and solvent the finished products may be subjected to a finishing treatment consisting of steam treatment at a temperature between 180 and 230 C.

When the alkaline earth metal is calcium, suitable quantities of reactants are one. part by weight of quicklime, from 0.2 to 0.4 part by weight of water, 3 to and for preference 3.5 to 4 parts by weight of phenol, 4 to and for preference 4.5 to 5.5 parts by weight of solvent and 3.5 to 5 parts by weight of an oil solution of calcium sulfonate containing 40 to 50 percent actual sulfonate or the corresponding quantity of purified sulfonic acid. It will be noted that 3.5 to 5 parts of an oil solution of calcium sulfonate of the stated concentrations correspond to 1.4 to 2.5 parts of actual sulfonate.

When using calcium as the alkaline earth metal in accordance with the above procedure, an additive concentrate of colloidally dispersed calcium carbonate is obtained having a calcium content of about 12 to 13 percent by weight and a total base number, or alkalinity index in the approximate range of 300 to 320. If one attempts to increase the total base number by the above procedure, by using larger proportions of base, the products thereby obtained have such a high viscosity that it is impossible to use them. Now it is desirable to improve further the lubrication of engines, in particular the lubrication of certain diesel engines operating under difficult conditions with fuels containing a high proportion of sulfur, and for this purpose additives that are as alkaline and detergent as possible must be created. Accordingly in a modification of this invention it is possible to increase both the alkalinity and the detergency of the products obtained, without their viscosity attaining unacceptable values.

This modification or improvement involves the addition to the reaction mixture, within which carbonation is carried out, before or after the introduction of carbon dioxide, but before the distillation of the liberated phenol and the solvent, of a dispersant that is diflerent from the hydrocarbon sulfonic acids and their metal salts. This modification has the quite unexpected result that it is possible to increase the proportion of base used until products are finally obtained whose total base number reaches or exceeds 400 and whose viscosity is acceptable.

For carrying out this modification of the present invention, the following method of operation is preferably used, in the description of which the quantities that are not expressed specifically in mols are understood to be by weight.

A solution is made of 1 part phenol dissolved in 1 to 1.5 parts of a solvent (referred to as S) and an alkaline earth base is added in the proportion of 1 mol of base to at most 2.2 mols of phenol. While the base reacts with the phenol at ambient temperature, it is preferable to operate at a temperature of about 70 to C. For preference, to assist the reaction, about 1 mol of water is added per mol of base; conditions that are very favorable to the reaction, but which can nevertheless be departed from considerably, are then obtained by keeping the mixture at about 120 C., with stirring and under a stream of nitrogen which carries off a portion of the water previously added. Once the reaction is completed, i.e. under the aforesaid conditions afler an hour or two, an alkaline earth metal phenate is obtained in the form of a fine dispersion which does not decant, in the reacting mixture.

To this mixture there is added from 0.2 to 1 part of an oil solution of a hydrocarbon sulfonic acid or a salt of that acid, which compounds are referred to below as R and then, at a temperature between about 80 and C., carbon dioxide is injected into this mixture until the phenate has reacted completely. According to the present improvement, there is added moreover, either before or after the injection of carbon dioxide, a solution of a dispersant R in a quantity such that from 0.1 to 1 part, or better still, from 0.2 to 0.5 part of R is employed for each part of pure R,. if, for instance, the solutions of R, and R each contain 40% i 10% active substance,

from 0.02 to 0.6 part approximately of the solution of R is added.

The order in which the alkaline earth base and R are incorporated'can be reversed without drawback.

Advantageously, after causing the carbon dioxide to react on the phenate, but before distilling off the phenol thus liberated, a further portion of alkaline earth base can be added to the mixture in the proportion of 1 mol at most to 2.2 mols of phenol present so as to form phenate again, then carbonating as before.

The solvent (S) and the phenol liberated by carbonation are finally and recovered; they can be re-used indefinitely. The final traces of phenol can be eliminated by distilling with steam. Finally after filtration, an additive is obtained whose alkalinity index is between 350 to 450 and whose viscosity is less than 400 cSt at 983 C.

The second dispersant R, referred to above is soluble in mineral oils and is preferably used in the process in the form of a concentrate, e.g. 30 to 50 weight percent in oil.

R may comprise a thioacid of phosphorus obtained by reaction of 5 to 30 weight percent of a sulfide of phosphorus with a hydrocarbon material such as a terpene, e.g. alphapinen, or a polyolefin, e.g. a polymer of a C, to Q, olefin wherein the polymer has a molecular weight of about 400 to about 100,000, e.g. polyisobutylene of 400 molecular weight or 1,000 molecular weight reacted with a sulfide of phosphorus such as 10 to 20 wt. percent of P 8 Treatment of such polymers with sulfides of phosphorus is well known in the art. Alkaline earth metal salts of such acids can also be used, e.g. the calcium salt of P 8 treated polyisobutylene of about 1,000 average molecular weight.

R may furthermore consist of an alkyl phenol or a compound derived from an alkyl phenol, having at least 12 to 15 carbon atoms and up to 24 carbon atoms per molecule, e.g. a sulfide of an alkyl phenol obtained by treating with sodium dichloride an alkylphenol or the alkaline earth salt obtained by causing an alkaline earth base to react on the said alkyl phenol sulfide. Such alkyl phenols or alkyl phenol sulfides include hexyl phenol, nonyl phenol, dodecyl phenol, hexadecyl phenol, the sulfides of any of said phenols, and the alkaline earth metal salts of any of said phenols or their sulfides.

R can also be a monocarboxylic acid, dicarb'oxylic acid, or acid anhydride characterized by having a long chain hydrocarbon group with a total molecular weight in the range of about 300 to about 2,800, i.e. having hydrocarbon groups with at least 20 carbon atoms and up to about 200 carbon atoms. Procedures for preparing such acids and anhydrides are well known in the art; see for example US. Pat. No. 3,489,619, columns 2, 3 and 4.

For the present invention the monocarboxylic acids are preferably obtained by causing a carboxylic acid having ethylene unsaturation in the alpha-beta position of the acid function, for instance acrylic or methacrylic acid, to react with a monochlorinated C to C polymer or copolymer, of suitable molecular weight, in particular with a chlorinated polyisobutylene having an average of one chlorine atom per mol. By causing these same monochlorinated polymersor copolymers of C to C olefins to react with maleic anhydride, alkenyl succinic anhydrides are obtained whose derivatives, and in particular alkenyl succinic acids and their salts, constitute particularly interesting dispersion agents for use in the present invention. The said derivatives are preferably the salts obtained by causing the oxide or hydroxide of an alkaline earth metal to react on alkenyl succinic anhydrides of molecular weight between 300.and 2000, better still between 700 and 1,000, these anhydrides being preferably polyisobutenyl succinic anhydrides.

The improved procedure according tothe present invention makes it possible to prepare new additives which are remarkably effective as detergents, as inhibitors of varnish formation and as anti-rust agents.

Preference is given to additives in which the alkaline earth metal is calcium. These additives, when prepared by the process improvement involving use of an additional dispersant R, are characterized by an alkalinity index between 350 and 450, by a viscosity less than 400 centistokes at 98.9 C and by the fact that they contain, in colloidal solution in a light mineral oil, from 30 to 40 percent calcium carbonate, from 15 to 25 percent calcium hydrocarbon sulfonate having a molecular weight preferably between about 800 and 1,200, and from 2 to percent R.

The overbased additive concentrates of this invention can be incorporated into lubricating oil compositions in various proportions, ranging from about 0.5 to about 30 weight percent, and dependent upon the type of lubricant composition and the qualities it is desired to'obtain. For instance, as regards lubricating oils for marine engine cylinders, the additive concentrate according to the invention can be used in proportions of to 30 percent, or better still, from to percent by weight of the additive concentrate, based on the lubricating composition. The products according to the invention meet in particular needs of diesel engines which call for thermally very stable additives, furnishing little ash, and whose alkalinity index, i.e. total base number attains at least 250. I

Should it be desired to confer anti-rust properties upon an engine oil or motor oil, the additive concentrate can be used in proportions of 0.5 to 1 percent by weight. The working proportions of this additive concentrate as dispersing agent and inhibitor in a lubricating oil will be in the region of 3 to 6 percent by weight.

The following examples, which are given by way of illustration and in no way restrictively, will better show the scope and importance of the present invention.

EXAMPLE 1 Preparation of Product A A mixture consisting of 1,080 g. benzyl alcohol and 810 g phenol was heated to C. While the mixture was stirred 290 grams of slaked lime was added in 5 minutes; 15 minutes later, the product obtained consisted of a white flaky suspension which did not settle. This suspension was placed in 900 g of an oil concentrate of 40 weight percent of calcium sulfonate and 60 weight percent of a diluent parafi'mic oil having a viscosity of about SSU at 100 F. When the mixture had been well stirred, the temperature was gradually raised to 90 C. in a stream of C0 240 liters of CO were used, which represented roughly three times the theoretical quantity.

The benzyl alcohol and phenol distilled over; there remained a viscous brown oil which, after filtration on a Buchner funnel, contained 12.2 percent calcium (product A). Comparative Test l Repeating Example 1, but using a quantity of phenol reduced to 368 g, i.e. a molar ratio phenol/lime of 1, the product was obtained only by very difficult filtration and contained only 4.3% Ca, which shows the need for using at least a stoichiometric quantity of phenol in relation to the lime. Comparative Test 2 Likewise, by way of comparison, a mixture of isopropyl alcohol and phenol was used by a prior art process, consisting of saturating with carbon dioxide after distilling off the phenol, water and alcohol. The procedure was as follows. 900 g calcium sulfonate concentrate containing 40 percent sulfonate, similar to that mentioned above, 430 g isopropyl alcohol, 810 g phenol and 650 g water were mixed together. The mixture was heated to 90 C., treated with 290 g slaked lime and stirred for 2 hours at the same temperature. It was then heated to C., which brought about the distillation of the isopropyl alcohol and of almost all the water involved. The resulting material was treated at 150 C. with a stream of CO for 2 hours at a delivery'rate of 6 liters per minute. The CO,- treated product, after very difficult filtration, had a calcium content of only 4.7 percent and an alkalinity index, or total base number, of 92.

EXAMPLE 2' Preparation of Product B The same operations as in Example 1 were performed as before, using a quantity of 368 g of phenol. A distillate of 1,080 g of benzyl alcohol and 368 g of phenol was obtained.

With the distillate thus obtained, the previous operations were repeated with 368 g fresh phenol, which correspond to a molar ratio phenol/lime of 2. The further new distillate thus obtained (1,080 g. benzyl alcohol and 736 g phenol) was treated with 74 g of fresh phenol, (a molar ratio phenol/lime of 2.2), and mixed with 900 g of an oil solution of calcium sulfonate with 40 percent calcium sulfonate; the mixture thus obtained was treated with 290 g slaked lime. After obtaining a perfectly homogeneous mixture, the product was treated with 270 liters CO then shipped and filtered to give Product B, which contained 12.53 percent calcium.

EXAMPLE 3 with CO at 80 C. in the proportion of 15 liters per hour. 0n

completion of this treatment, 45 g quicklime was added and the product, after mixing, was again treated with 90 liters C0,, stripped and filtered. The product obtained had a calcium content of 12.3 percent (Product C).

Comparative Test 3 By replacing the benzyl alcohol in Example 3 with an equivalent quantity by weight of phenol, an unfilterable product was obtained; by diluting the reaction product in a been absorbed, while the temperature was raised to 250 C. so as to distill off completely the water, benzyl alcohol and phenol. The final Product A3 contained 12.8 percent calcium and had an alkalinity index of 317. i

light solvent, a little product could be filtered which, afler 5 stripping, had a Ca content of 4.2 percent. This shows that the dispersion of the calcium phenate can only take place in the EXAMPLE 7 presence of a polar solvent if it is desired to obtain high con-, Preparation of Product A4 tents of calcmm- 10 The operations described in Example 6 were repeated, but

EXAMPLE 4 the foregoing sulfonic acid was replaced by a sulfonic acid obtained by sulfonating an alkylate derived by alkylation of Preparation of Product A1 benzene by means of a polypropylene of mean carbon conden- The distillate obtained in Example 1 was added to 900 g sation equal to 24. The final product A4, after filtration, had a neutral calcium sulfonate concentrate containing 50 percent 1 5 calcium content of l2.5 perc n and alinity ind x f 310. sulfonate derived from the sulfonation of polydodecyl benzene. While stirring, 200 g quicklime was admitted at 80 C. After the formation of a pale brown suspension, which did EXAMPLE 8 not decant the product was treated at 80 C. with 'carbon The products obtained as described above, namely A, A1, 3.12:: arx'rsrzriazfisatzs55.1.:2552223 A3. A4. 1m lubricating peramre was gradually raised to c. while distilling glrisptlgiected to eng ne tests. The following formulations were the water, benzyl alcoholand phenol. After this distillate had been removed and the temperature had been, reduced to 180 ifggz z gi g i g if i r fg' 7a6vlscosny C., 1 kg steam was incorporated during one hour in the y ex residual product. After filtration, the product obtained had a g' f f 1 welghtoofa lubncung P a vlscosl 22'? and a we be numbmf was;ssgrosszizrissm z;at...

' of barium carbonate in a mixture containing nonylphenol and 7 E MPLE 5 polybutene treated with P 8 this additive contained about 15 P f f? 0d t A2 percent barium.

Para 0 r 3.84 rcent b wei t of one of the rod ts A A1 A2 An alkylate obtained by alkylation of benzene withan olefin A3 y 8h p obiamed by Polymemmg Pmpylene BF3 and charm Therewere thus prepared respectively oil blends A, A1 A2, tenzed by an average of 24 carbon atoms per molecule, was A3, A4! sulfonated with gaseous SO; in the presence of S O 500 g cor- A control blend was prepared in the Same manner, using in 'esPondmg calcmm sulfonate {lavmg concen' place of one of the aforementioned products of the present intratron of percent sulfonate was mixed with 250 g phenol, vendor! a commercial overbased additive comm-fling 26 9 g benzyl and 33 gwater' The {mxtm'e was m cent calcium sulfonate, 30 percent colloidal calcium carw1th g qu1ckl1me and then, after formatlon of a homogenebonate and 44 percent lubricating oil ous suspension, treated at 80 C. with Co, until the theoretical 40 These blends were subjected to a esel engine test of 68 quantity corresponding to the total conversion of the lime into how duration in a Lstmke Caterpillar diesel engine having calcium carbonate had been absorbed. On completion of tlus an antechamber Supercharged and a bore of 130 2 mm a "'t F fz 'gf z fifi g z zggg g fig stroke of 165.1 mm and a cylinder capacity of 2.19 liters. n18 was ag ea e engine speed was 1,800 rpm and the fuel was a as oil of 1 erty had been absorbed after whlch the profiuct was Stu-red and 45 cent sulfur content. The initial oil charge was 557 liters. p filtered. The product obtainedhad a calcium content of 12.3 At the end of Such test the engine was disassembled and percent and an alkalinity Index of rated in accordance with standard procedures. The results ob- EXAMPLE 6 tained are given in Table l and show that the additives of this invention were, on the whole, superior to the commercial Preparation of Product A3 product.

TABLE I Blend Maximum Control rating 1 A A1 A2 A3 A4 blend Percent carbon 15!; groove 0 42. 2 71 59 57 88 Rating for roo'risiir'ihb Zir'ep'fi .30 2518 28'. 6 2s: 4 25: 9 26'. 3 1312 Rating {or ring surface (except 1st) 30 24. 9 24. 3 26 24. 2 25. 4 37. 5 Rating for piston skirt 10 9. E 10 9. 92 J. J J. l) J. 8 Rating for piston bottom 1O 8. 4 8.3 8. 5 8. 2 8.6 4. 8

1 All are merit ratings exceptgpercent carbon. Rating method was:

Series III oils; spec. MIL-L-451 1D and 1G Caterpillar tests applied to A mixture was prepared from 290 g technical white oil, 600 65 The following are examples of the modified procedure of g benzyl alcohol, 500 g phenol, 5 g calcium chloride, 40 g water and 710 g of an oil solution of purified sulfonic acids, derived from the sulfonation of the residue from making dodecyl benzene and containing 69 percent sulfonic acid and 0.1 percent sulfuric acid. This mixture was'heated to C.

the invention using a dispersant R along with the metal sulfonate.

EXAMPLE 9 and treated with 150 g quicklime and stirred for one hour. The

product obtained was treated with carbon dioxide gas until the stoichiometric quantity had been absorbed: g quicklime was incorporated and, after stirring, the new product formed was tre d i h (:0 il the i hj m quantity h d 75 presence of aluminum chloride. After the elimination of un- As a product of type R there was prepared as follows a calcium sulfonate in solution in a light paraffin oil. An olefin averaging C prepared by polymerizing at 40 C. propylene with the aid of HR, was used to alkylate benzene in the reacted benzene and the products distilling below 350 C., the residue was 'sulfonated by gaseous S0,, in the presence of S0,. The sulfonic acid obtained was purified by washing in concentrated hydrochloric acid'in the presence of hexane and, after dilution by a light paraffin oil having a viscosity of 32 centistokes at 37.8 C., was neutralized by lime in the presence of water and small quantities of calcium chloride.

The product, purified by heating to 150 C. and filtered, was-a 38 percent solution of calcium sulfonate'of molecular mass 1040. This solution contained 2 percent calcium (Product 9- A). v Part B Preparation of Metal Salt of Acid of Phosphorus As product of type R, there was preparedas follows a calcium salt of organic thioacids of phosphorus, in solution in a light mineral oil. A polyisobutylene of 780 average molecular weight was treated with 15 percent of its weight of P 8 at220 C. for 6 hours. The product obtained was treated with steam'at 180 C. for 2 hours and then filtered. The resultant product was diluted a light paraflin oil having a viscosity of 32 centistokes at 37.8 C., then neutralized by lime in the presence of toluene, the latter solvent serving to carry ofifthewater. After distilling 011 the toluene and filtering, an oil solution was obtained of calcium salt of phosphorus thioacids, in 40 percent concentration, which contained 1.7 percent calcium (Product 9-B).

Part C Preparation of Metal Alkyl Phenol Sulfide As product of type R there was likewise prepared as follows the calcium salt of an alkyl phenol sulfide in solution in a light paraffin oil. A nonyl phenol obtained by alkylation of phenol by tripropylene with the aidof BF was treated with sulfur dichloride in the presence of hexane. After eliminating the hexane, then diluting with a light paraffin oil having a viscosity of 32 centistokes at 37.8 C, this product was neutralized by lime in the presence of methyl alcohol. After elimination of the alcohol and filtration, an oil solution was obtained of calcium salt of alkyl phenol sulfide in 40 percent concentration, which contained 2.8 percent calcium (Product 9-C).

Part D Preparation of Metal Salt of Polyisobentenyl Succinic Acid As product of type R there was furthermore prepared as follows the calcium salt of polyisobutenyl succinic acids in solution in a light paraffin oil. polyisobutylene having an average molecular weight of 780 was chlorinated at about 100 C. with gaseous chlorine in order to produce a chlorinated polyolefin containing 4.5 percent chlorine.

815 grams (1 mol) of this chlorinated olefin was caused to react with 118 g (1.2 mol) maleic anhydride, the mixture being kept at about 180. One mol hydrochloric acid was liberated during the reaction. When the liberation of hydrochloric acid had ceased, the product was heated in a stream of nitrogen to eliminate unreacted maleic anhydride.

This yielded 870 g (about 1 mol) of polyisobutenyl succinic anhydride, which was then diluted with 1300 g of a parafi'ln oil having a viscosity of 32 cSt at 37.8 C., and the diluted mixture was treated with 80 g calcium hydroxide in the presence of 200 ml of methanol. After distilling off the methanol and filtering, the calcium salt of polyisobutenyl succinic acids was obtained in 40 percent solution in paraffin oil. This solution contained 1.8 percent calcium (Product 9-D).

EXAMPLE 10 A mixture of 240 grams of calcium sulfonate Product 9-A, 440 g phenol, 475 g benzyl alcohol and 40 g water was heated to 80 C. while stirring. Then 100 g quicklime was incorporated and the mixture was stirred for 1 hour at 120 C. in a stream of nitrogen, 22 g water, thereby being removed. Carbon dioxide gas was then introduced at a rate of 2 liters per minute for 2 hours, the reaction mixture being heated from 120 to 160 C. Then 60 grams of the metal salt of the thioacid of phosphorus, Product 9-B, was added. The mixture was then heated to 250 C. to distill off water, phenol and benzyl alcohol and, after allowing to cool to 180 C., it was treated for 2 hours with a quantity of steam corresponding to 300cc water. The product. thus treated was filtered. It was a clear brown product containing 14.4 percent calcium, having an alkalinity index of 367 and a viscosity of 325 centistokes at A mixture of 750 gramsof calcium sulfonate, Product 9-A, 250 grams of calcium alkyl phenol sulfide, Product 9-C, 1320 g phenol, l760g benzyl alcohol and 110 g water, was heated to 80 C. while stirring. Than 333 g quicklime was incorporated and the mixture was stirred for 2 hours at 120 C. in a stream of nitrogen, which removed 80 g of water. Carbon dioxide gas was then introduced at a rate-of 3 liters per minute for 2 k hours, while heating the reacting mixture from 120 to 160 C. The product was then heated to 250 C. to distill off water, phenol and benzyl alcohol, and then treated at 180 C.

for 2 hours with a quantity of steam corresponding to one liter of water. After filtration, the clear brown product contained 15.7 percent calcium, and had an alkalinity index of 405 and a viscosity of 278 cSt at 989 C. The composition of this product was as follows:

1 Calcium alkylaryl sulfonate 18.3%

Calcium salt of nonylphenol sulfide 6.4% Colloidal calcium carbonate 35.4% Light paraffin oil 39.9%

EXAMPLE 12 A mixture of 720 g calcium sulfonate product 9-A,180 g calcium polyisobutenyl succinate product 9-D, 1,080 g phenol, 1,440 g benzyl alcohol and g water was heated to 80 C. while stirring. Then 170, g quicklirne was added and the mixture was stirred for 1 hour at C. in a stream of nitrogen, thereby removing 70 g water. Then CO was introduced at a rate of 3 liters per minute for 2 hours while heating the reacting mixture from 120 to C. The temperature was then raised to 250 C. to distill off water, phenol and benzyl alcohol, and after allowing the mixture to cool to 180 C., it was treated for 2 hours with a quantity of steam corresponding to 1 liter of water. The product thus treated was filtered. lt was a brown product containing 13.8 percent calcium, with an alkalinity index of 355 and a viscosity of 310 cSt at 989 C., and its composition was as follows:

Calcium alkylaryl sulfonate 20.6%

Calcium polyisobutenyl succinate 5.4%

Colloidal calcium carbonate 32.4%

Light paraffin oil 41.6%

Comparative Test 4 The following experiments show the benefit of using a second dispersant R with the metal sulfonate Rl.

a. The method of operation of Example 10 was repeated, 240 g product 9-A being replaced by 240 g product 9-B. The result was a gelified product, unfilterable and insufficiently carbonated.

b. The method of operation of Example 10 was again repeated, omitting the addition of 60 g product 9-B afier carbonation. The result was a solid unfilterable product.

c. The method of operation of Example 11 was repeated, the 750 g of product A being replaced by 750V 8 of product C. The result was a cloudy filterable product-having the consistency of a grease.

d. The method of operation of Example 11 was again repeated, the 750 g of product 9-A and the 250 g of product 9-C being replaced by 1,000 g of a solution con- 1 l taining the same sulfonate as product 9A, but in a concentration of 50 percent instead of 38 percent. After filtration, the product contained 12.6 percent calcium and had an alkalinity index of 310. The use of a solution of 50 percent sulfonate is necessary in this case to obtain a sufficient colloidal stability.

It will therefore be seen that the use of a mixture of calcium sulfonate and other dispersant makes it possible to prepare products with higher alkalinity than those obtained from calcium sulfonate only. Moreover, the proportion of colloidal calcium carbonate, referred to the total of the other active constituents, is greater in the additive where an additional dispersant has been used.

EXAMPLE 13 Two motor oil compositions were prepared as follows: Oil A 10 percent by weight of an oil of viscosity 32 cSt at 37.8 C. and viscosity index 105.

84 percent weight of an oil of viscosity 129 cSt at 37.8 C. and viscosity index 98.

6 percent product of Example 1 1 Oil B (reference) Same base oils 6 percent commercial high alkalinity calcium sulfonates containing 28 percent by weight pure calcium sulfonate, 27 percent by weight colloidal calcium carbonate and 45 percent by weight mineral oil.

These oils were subjected to the Caterpillar engine test These results show clearly the increased detergent, and inhibiting properties of the additive of Example 11 as compared with the commercialadditive. in particular, the reduction of the deposits of carbon in the first groove is very significant.

EXAMPLE. 14'

In order to demonstrate the improved anti-rust properties of an additive of higher alkalinity index as compared toone of lower alkalinity index, the product obtained in Example 12 and a high alkalinity additive prepared by the process of Example '7 were subjected to the special tests provided for in military standard MIL-L -2 1 260A.

For this purpose, two oil compositions were prepared:

Oil H 1 containing:

5 percent of the additive according to Example 12, having an alkalinity index of 355. I I

95 percent of a naphthenic oil having a viscosity of 9.6 cSt at 98.9 C. and a viscosity index of 80.

Oil H2 containing:

5 percent of a high alkalinity additive prepared according to the procedure described in Example 7, characterized by an alkalinity index of 310.

95 percent of the same naphthenic oil as before.

These oil compositions were subjected to the following tests:

a. Acid neutralization test. This very stringent test, which consists of soaking metal test pieces in a highly diluted solution of hydrobromic acid, then in the oil to be tested, allowing them to drain for 4 hours in the open air, furnished the following results: 1

Oil H 1: slight traces of rust (acceptable result) Oil H2: a number of rust spots (poor result) v b. Brine immersion test. This test provides for the draining over a period of hours of metal test pieces that have previously been soaked in the test oil, then immersion for 20 hours of test pieces splashed with synthetic sea water.

' 'These test pieces are then washed, dried and examined.

This test furnished the following results:

Oil H1: no trace of rust (excellent result) Oil H2: a few corrosion spots (result barely acceptable) c. Rust test in damp atmosphere (ASTM D-l748-62). This test consists of soaking metal test pieces in the oil being tested, keeping them in a constantly ventilated cabinet containing water at its boiling point. The test is halted when the test pieces display incipient corrosion and the antirust properties of an oil are rated by the time the soaked test piece remains in that oil. This test fumished the following results: Oil H1: 2] days; and Oil H2: 14 days.

What is claimed is:

l. A process for preparing a high alkalinity oil-soluble alkaline earth metal hydrocarbon sulfonate which comprises reacting carbon dioxide with an alkaline earth metal base selected from the group consisting of metal oxide, metal hydroxide and metal phenate in the presence of a sufficient quantity of a dispersant capable of maintaining a colloidal dispersion of the resulting alkaline earth metal carbonate, in the presence of an amount of phenol in excess of the stoichiometric amount thereof needed to convert total alkaline earth metal base present to phenate, and in the presence of a solvent selected from the group consisting of benzyl alcohol, tetrahydrofurfuryl alcohol, cyclohexanol, and methyl cyclohexanol, said dispersant being selected from the group consisting of (A) alkaline earth metal sulfonate and (B) a mixture of alkaline earth metal sulfonate and a second material selected from the group consisting of (a) thioacid of phosphorus; (b) alkyl phenol; (c) alkyl phenol sulfide; (d) long chain hydrocarbon monocarboxylic acid, dicarboxylic acid, or acid anhydride of from about 20 to 200 carbon atoms in said long chain; and alkaline earth metal salts of any of (a),

- (b), (c), or (d); the molar quantity of carbon dioxide used in the reaction exceeding the molar quantity of total alkaline earth metal base, and the quantity of said solvent equalling at least about 80 weight per cent of the amount of phenol involved in the reaction.

2. Process as defined by claim 1 wherein the proportion of said second material to said sulfonate is from about 0.1 to about 1 part by weight per weight of sulfonate.

3. Process as defined by claim 1 wherein said alkaline earth metal is calcium.

4. Process as defined by claim 1 wherein said thioacid of phosphorus is the product of reaction of an olefinic hydrocarbon with a sulfide of phosphorus.

5. Process as defined by claim 1 wherein said second dispersant material is the calcium salt of polyisobutenyl succinic acid.

6. Process as defined by claim 1 wherein said second dispersant is calcium nonyl phenol sulfide.

7. Process as defined by claim 1 wherein said sulfonate is an alkylated benzene sulfonate.

8. Process as defined by claim 1 wherein said sulfonate is a petroleum oil sulfonate.

9. Process as defined by claim 1 wherein said solvent is benzyl alcohol.

10. Process as defined by claim 1 wherein said calcium sulfonate is in the form of a concentrate in hydrocarbon oil.

11. Process as defined by claim 1 wherein metal hydrocarbon sulfonate is prepared in situ in the reaction mixture by reaction of free sulfonic acid with calcium base.

12 Process as defined by claim 1 which includes the step of removing free phenol and solvent'from the reaction product by distillation.

13. A sulfonate of high alkalinity when prepared by the process of claim 1.

15. A process for preparing a calcium hydrocarbon sulfonate of high alkalinity which comprises reacting, at a temperature within the range of about 80 to 250 C., carbon dioxide with a calcium base selected from the group consisting of calcium phenate, quicklime, and slaked lime, in the presence of sufficient oil-soluble calcium hydrocarbon sulfonate to maintain said colloidal dispersion, in the presence of an amount of phenol in excess of the stoichiometric amount thereof needed to convert total calcium base present to phenate, and in the presence of a solvent selected from the group consisting of benzyl alcohol, tetrahydrofiirfuryl alcohol, cyclohexanol, and methyl cylohexanol, there being present in said reaction mixture for each part by weight of total calcium base, calculated as quicklime, from 3 to 5 parts by weight of phenol and from 4 to parts by weight of said solvent, the total amount of carbon dioxide used in the reaction exceeding one mol of carbon dioxide per mol of total calcium base.

16. In a process wherein a calcium hydrocarbon sulfonate of high alkalinity is prepared by reaction of carbon dioxide with a calcium base selected from the group consisting of quicklime and slaked lime, in the presence of calcium hydrocarbon sulfonate, the improvement which comprises conducting said reaction at a temperature within the range of about 80 to 250 C. in the presence of calcium phenate, there being present phenol in an amount in excess of the stoichiometric amount needed to convert all of the calcium base to calcium phenate, and in the presence of a polar solvent selected from the group consisting of benzyl alcohol, tetrahydrofurfuryl alcohol, cyclohexanol, and methyl cyclohexanol, the proportions of reactants employed in said reaction corresponding, in parts by weight, to one part of quicklime, from 0.2 to 0.4 part of water, from 3 to 5 parts of phenol, from 4 to 10 parts of said solvent, and from 1.4 to 2.5 parts of calcium hydrocarbon sulfonate, the quantity of carbon dioxide used in the reaction exceeding one mol of carbon dioxide per mol of the total calcium represented by calcium base and calcium phenate.

17. Process improvement as defined by claim 16, wherein calcium phenate is prepared in situ in the reaction mixture by reaction of calcium base with phenol.

18. Process improvement as defined by claim 16, wherein said reaction of carbon dioxide with calcium base is conducted in more than one stage, with a portion of the total amount of carbon dioxide and base being used in each stage.

t l I!

Claims (17)

1. 2. Process as defined by claim 1 wherein the proportion of said second material to said sulfonate is from about 0.1 to about 1 part by weight per weight of sulfonate.
2. 3. Process as defined by claim 1 wherein said alkaline earth metal is calcium.
3. 4. Process as defined by claim 1 wherein said thioacid of phosphorus is the product of reaction of an olefinic hydrocarbon with a sulfide of phosphorus.
4. 5. Process as defined by claim 1 wherein said second dispersant material is the calcium salt of polyisobutenyl succinic acid.
5. 6. Process as defined by claim 1 wherein said second dispersant is calcium nonyl phenol sulfide.
6. 7. Process as defined by claim 1 wherein said sulfonate is an alkylated benzene sulfonate.
7. 8. Process as defined by claim 1 wherein said sulfonate is a petroleum oil sulfonate.
8. 9. Process as defined by claim 1 wherein said solvent is benzyl alcohol.
9. 10. Process as defined by claim 1 wherein said calcium sulfonate is in the form of a concentrate in hydrocarbon oil.
10. 11. Process as defined by claim 1 wherein metal hydrocarbon sulfonate is prepared in situ in the reaction mixture by reaction of free sulfonic acid with calcium base.
11. 12. Process as defined by claim 1 which includes the step of removing free phenol and solvent from the reaction product by distillation.
12. 13. A sulfonate of high alkalinity when prepared by the process of claim 1.
13. 14. A lubricating oil containing 0.5 to 30 percent by weight of the sulfonate defined by claim 13.
14. 15. A process for preparing a calcium hydrocarbon sulfonate of high alkalinity which comprises reacting, at a temperature within the range of about 80* to 250* C., carbon dioxide with a calcium base selected from the group consisting of calcium phenate, quicklime, and slaked lime, in the presence of sufficient oil-soluble calcium hydrocarbon sulfonate to maintain said colloidal dispersion, in the presence of an amount of phenol in excess of the stoichiometric amount thereof needed to convert total calcium base present to phenate, and in the presence of a solvent selected from the group consisting of benzyl alcohol, tetrahydrofurfuryl alcohol, cyclohexanol, and methyl cylohexanol, there being present in said reaction mixture for each part by weight of total calcium base, calculated as quicklime, from 3 to 5 parts by weight of phenol and from 4 to 10 parts by weight of said solvent, the total amount of carbon dioxide used in the reaction exceeding one mol of carbon dioxide per mol of total calcium base.
15. 16. In a process wherein a calcium hydrocarbon sulfonate of high alkalinity is prepared by reaction of carbon dioxide with a calcium base selected from the group consisting of quicklime and slaked lime, in the presence of calcium hydrocarbon sulfonate, the improvement which comprises conducting said reaction at a temperature within the range of about 80* to 250* C. in the presence of calcium phenate, there being present phenol in an amount in excess of the stoichiometric amount needed to convert all of the calcium base to calcium phenate, and in the presence of a polar solvent selected from the group consisting of benzyl alcohol, tetrahydrofurfuryl alcohol, cyclohexanol, and methyl cyclohexanol, the proportions of reactants employed in said reaction corresponding, in parts by weight, to one part of quicklime, from 0.2 to 0.4 part of water, from 3 to 5 parts of phenol, from 4 to 10 parts of said solvent, and from 1.4 to 2.5 parts of calcium hydrocarbon sulfonate, the quantity of carbon dioxide used in the reaction exceeding one mol of carbon dioxide per mol of the total calcium represented by calcium base and calcium phenate.
16. 17. Process improvement as defined by claim 16, wherein calcium phenate is prepared in situ in the reaction mixture by reaction of calcium base with phenol.
17. 18. Process improvement as defined by claim 16, wherein said reaction of carbon dioxide with calcium base is conducted in more than one stage, with a portion of the total amount of carbon dioxide and base being used in each stage.