US2786028A - Anti-corrosive lubricating oil - Google Patents

Description

United States. PatentO ANTI-CORROSIVE LUBRICATIN G OIL Ralph I. Gottshall, Willow Grove, and Raymond T. Kern, .lr., Upper Merion Township, Montgomery County, Pa., and John G. Peters, Audubon, N. 3., assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application May 4, 1955, Serial No. 506,074

6 Claims. (Cl. 252-325) This invention relates to mineral oil compositions and more particularly to mineral oil compositions adapted to prevent rusting and corrosion of metal surfaces which are exposed to moisture.

Simple mineral oil films afford only limited protection to metal surfaces against rusting and other types of corrosion and, in general, can not be relied upon to provide sufficient protection against rust formation in the presence of moisture. Various lubricating compositions have, heretofore, been disclosed for protecting metal surfaces against rusting and corrosion but the prior compositions have not been entirely satisfactory. It has become common practice to employ corrosion inhibitors or anticorrosion agents as additives in oil compositions for the purpose of providing additional protection against rusting and corrosion. Such additives have been used in various types of lubricating compositions such' as machine oils, internal combustion engine and diesel lubricating oils, turbine oils, greases, etc., as well as in slushing oils and fuel oils. Some of the prior compositions have exhibited good resistance to oxidation, but they have not given complete protection against rusting and corrosion of metal turbine parts which are exposed to moisture. Other compositions, while being satisfactory for use in the presence of relatively pure water or water vapor, do not provide adequate protection against corrosion in the presence of salt water.

In marine storage and use, lubricating oils frequently become contaminated with small amounts of sea water. When oils thus contaminated are subsequently used, substantial corrosion of metal surfaces with which the contaminated lubricant comes in contact may be encountered. It is desirable, therefore, to provide a lubricating composition which will protect metal surfaces from salt water corrosion and which will prevent the corrosion of metal surfaces even though the composition may have been contaminated with salt water.

The present invention is based on a particularly effective lubricating composition having good resistance to oxidation combined with good lubricating characteristics. The compositionof the present invention has the further desirable properties in that it protects metal surfaces from corrosion and rusting normally resulting when the metal is contacted with salt water. The improved lubricating composition of this invention consists essentially of.-a

homogeneous mixture of a mineral lubricating oil, an alkyl phenol, a substantially neutral addition product of isoamyl octylacid phosphate with a primary fatty amine containing from 8 to 18 carbon atoms, an alkenyl-substituted succinic acid anhydride whereinthe alkenyl group contains from to 18 carbon atoms, and an acid ester of (l) a dimeric acid derived from an unsaturated fatty acid containing from 6 to 22 carbon atoms and having from 2"to 3 ethyleniclinkages per molecule and the lubricating oil base or the lubricating oil base containing any one or more but less than all of the herein disclosed constituents.

The lubricating oil to which the other constituents are added is advantageously a highly refined paratfinic oil. By the term highly refined parafiinic oil we mean a petroleum lubricating oil which has been refined by one of the more drastic refining methods known in the art, for example, by conventional aluminum chloride refining or by a solvent extraction adapted to remove all or substan: tially all of the unsaturated and naphthenic constituents of the oil. Aluminum chloride refined or solvent extracted paraifinic base oil, such as a Pennsylvania oil provides an excellent base oil for the composition of the invention. However, drastically refined Mid-Continent and Gulf Coastal oil may also be used.

The alkyl phenol which is'used in accordance with the invention is advantageously a dior tri-alkylated phenol or cresol with at least one of the alkyl groups being a tertiary alkyl group. The alkyl groups are preferably those containing between 3 and 12 carbon atoms. Good results can be obtained with a tri-tertiary butyl phenol or a ditertiary butyl cresol. Examples of the preferred alkylated phenols are 2,4,6-tri-tertiary-butylphenol, 2,6-di-tertiarybutyl-4-methylphenol and bis(2-hydroxy-3tertiary-butyl 5-methylphenyl)methane. The alkyl phenols can be used in amounts of about 0.1 to about 5.0 percent by weight based on the weight of the total composition. The preferred amount, however, is between about 0.2 and about 1.25 percent by weight. 7

The fatty amine salt of isoamyl octyl acid phosphate which can be used in accordance with the invention is prepared by reacting isoamyl octyl acid phosphate with a primary fatty amine containing from 8 to 18 carbon atoms. One example of a primary fatty amine suitable for the purpose of this invention is cocoamine, which is a commercially available product prepared by converting coconut oil fatty acids into the corresponding amine. It consists mostly of monolauryl amine with minor amounts of adjacent homologues. The cocoamine salt of isoamyl octyl acid phosphate and its preparation are fully de} scribed in U. S. Patent No. 2,371,851 which issued on March 20, 1945 to Herschel G. Smith and Troy L, Cantrell. 'As disclosed in said patent, the cocoamine salt of isoamyl octyl acid phosphate can be readily prepared by reacting cocoamine with isoamyl octyl acid phosphate in approximately equimolecular ratios, the reaction being so controlled as to produce substantially neutral reaction mixtures having a pH value within the range 5.5 to 7.5, as illustrated in Examples 1 and 2 of that patent. The isoamyl octyl acid phosphate employed is a di-ester of orthophosphoric acid having the following formula:

This compound is "also known as 3-methylbutyl, Z-ethylhexyl acid orthophosphate. It readily reacts with cocoamine and other primary, fatty amines containing from 8 to 18 carbon atoms. Instead of cocoamine we'can use other primary fatty amines containing from .8 vto 18 carbon atoms. These amines include, mono-capryl, CH3(CH2)8CH2NH2, mono lauryl, mono myristyl, mono-palmityl and mono-stearyl amines. The fatty acid amine'salt of isoamyl octyl acid phosphate is preferably used in an amount between'about 0.01 and about 0.2 percent by weight based on the weight of the total com position. However, improved results can be obtained with an amount between about 0.001 and about 1.0 percent by weight.

The alkenyl-substituted succinic acid anhydridecan'be copolymers may also be formed. The alkenyl chain may contain from 5 to 18 or even more carbon atoms. The acid anhydrides. having an alkenyl group containing at least six carbon atoms are particularly advantageous. The especially preferred acid anhydrides are those in which. the alkenyl substituent contains a relatively large number of. carbon atoms, for example, 8 to 12 carbon atoms. In. illustrating the composition of the invention, we have used a commercially available material, dodecenyl succinic anhydride, obtained from National Aniline Division, Allied Chemical & Dye Corporation. The. alkenyl-succinic acid anhydride can be used in amounts of about 0.01 to about 0.3 percent by weight based on the weight of the total composition. Although some improvement in the rust inhibiting properties of the oil is obtained with increasing concentrations of alkenyl succinic acid anhydride, amounts in excess of 0.3 weight percent are, in general, undesirable because of the undesirably high neutralization value which the greater amount of. acid anhydride imparts to the oil.

The acid esters employed in accordance with this invention are the reaction products resulting from the esterification of a dimerized unsaturated fatty acid with a partial fatty acid ester of an alkitol anhydride. The ratio of reactants may range from one mol of dimerized acid per mol of partial fatty acid ester up to the number of mols of dimerized acid that is equal to the number of free hydroxyl groups in the partial fatty acid ester, per mol of partial fatty acid ester.

The esterification reaction is effected in conventional manner and under conventional conditions. Thus, while esterification may proceed slowly at room temperature, the reaction is normally advantageously accelerated by heating the reactants, usually with refluxing, and/ or by the use of conventional esterification catalysts, such as hydrogen chloride, sulfuric acid, or an aromatic sulfonic acid, such as p-toluene-sulfonic acid. The reaction may bedriven to substantial completion by removing one of the products of reaction. Since the herein disclosed dimeric unsaturated fatty acids, partial esters of. alkitol anhydrides, and their reaction products boil at a temperature substantially above the boiling point of water, the reaction conveniently may be driven to completion by removal of the water of esterification by distillation. The removal of water from the reaction mixture may be facilitated by mechanical agitation, or by bubbling an inert gas, such as nitrogen, through the reaction mixture.

By way of illustrating the foregoing process, one, two or three mols of dimerized acid may be esterified with one mol of .a partial fatty acid ester containing three free hydroxyl groups, under conventional reaction con ditions,,with the elimination, respectively, of one, two or three mols of water of esterification, to form, respectively, a mono-, .dior tri-acid or tricarboxylic ester of the dimerizedacidand the partial fatty acid ester.

If desired, the, reaction products may be prepared by eifecting esterification of the reactants in mineral oil solution. This expedient is advantageous in that it prevents localized overheating of the reactants. Moreover, the resulting-reaction products are in the form of mineral oil. concentrates, the use of which often facilitates solution-offlle additives in their ultimate vehicles.

.Theadimerized acids referred to above are dimers, i. e'., bimolecular addition products of conjugated or uncon jugatedrdienoic or itrienoicfatty acids having from 6 to 22 carbon atoms before dimerization. Dimeric acids derived from dienoic and trienoic fatty acids are well known and can be prepared by conventional methods which form no part of this invention.

More particularly, dimerized acids capable of forming the compounds utilized in the composition of this invention are prepared from dienoic or trienoic fatty acids having the generic formula CnHzn-mCOOl-I, where n is an integer of from 5 to 21 and x is 3 or 5. As will be evident, such monomeric acids contain from 6 to 22 carbon atoms and may contain 2 or 3 ethylenic linkages as the ratio of carbon to hydrogen increases, i. e.', as): increases from 3 to 5. Dimerized acids corresponding to the addition products of the foregoing acids therefore may be defined by the generic formula:

0 I i-OH Cn EIEn-z Tl-OH A where n is an integer of from 10 to 42 and where x is an even integer of from 6 to 10. These dimeric acids are therefore dibasic or dicarboxylic acids having from 12 to 44 carbon atoms.

Representative members of the class of dimerized acids capable of forming the compounds employed in the compositions of this invention are dimers of dienoic acids such as sorbic (hexadienoic), linoleic (octadecadienoic), humoceric (nonadecadienoic) and eicosinic (eicosadienoic) acids. Dimers of trienoic acids, for example, linolenic and eleostearic (octadecatrienoic) acids may also be used.

It is not necessary that both of the unsaturated fatty acid molecules of the bimolecular addition product be identical. Dimers of mixed. composition such as those obtained by dimerizing mixed dienoic, mixed trienoic or mixed dienoic and trienoic acids such as may be derived from certain naturally occurring drying oils, e. g., linseed oil and soybean oil, are quite satisfactory.

Dienoic and trienoic acids having 18 carbon atoms, especially those having conjugated olefinic linkages, are preferred for reasons of economy of procurement, ease of reaction and the general excellence of the additives prepared therefrom.

The partial esters of alkitol anhydrides and fatty acids adapted for use in the formation of the reaction products are those resulting from esterification with the desired fatty acid of at least one, but less than all, of the available hydroxyl groups of an alkitol anhydride. By alkitol anhydride is meant an intramolecular, monoor dian- .hydride of a polyhydric alcohol which contains at least 4 carbon atoms and at least 4 hydroxyl groups, or mixtures of said anhydrides. Representative of the class of alkitols are erythritol; pentitols, such as arabitol, xylitol and adonitol; and hexitols such as mannitol, dulcitol and sorbitol, just as the xylitans and sorbitans are representative of the alkitol anhydrides, -or alkitans.

Fatty acids capable of forming partial. esters of.alkitol anhydrides suited to the preparation of the additives utilized in this invention are the fatty acids containing from. 12 to 24 carbon atoms. These acids may be saturated or unsaturated, and they may be substituted with groups which do not adversely affect the oil-solubility or corrosion-inhibiting properties of the final reaction product. Representative of this group of acids are lauric acid, oleic acid, ricinoleic acid, stearic acid and lignostearic acid.

Partial esters capable of reacting to form the. reaction products include those formed by reacting a fatty acid of the foregoing kind with the desired alkitol anhydride in a molar ratio of at least 1:1, but less than that which would result in neutralization of all of the hydroxyl groups of-thealkitol anhydride; 'The used mixtures of partial fatty acid esters of alkit ol' anhydridesis also included within the scope of the invention. Specific examples of partial esters of alkitol anhydrides capable of reacting with dimeric unsaturated fatty acids to form acid esters which can be used in the composition of the invention are xylitan and sorbitan mono-, sesqui-, diand trioleates and stearates. Partial esters of hexitol anhydrides, i. e., anhydrides of polyhydric alcohols containing 6 carbon atoms and 6 hydroxyl groups, are preferred.

The partial esters ofalkitol anhydrides disclosed herein as well as the method of preparing the same are conventional and form no part of the present invention. Accordingly, they need not-be described in detail.

Representative specific examples of acid esters of dimeric acids with partial fatty acid esters of alkitans which can be used in the compositions of this invention are the monoand polycarboxylic acid esters of dimerized linoleic, linolenic and eleostearic acids with sorbitan and xylitan mono-, se'squi-,'-di-' and tri-oleates and stearates. Included within the foregoing representative class of compounds are mono-, di-, and triacid dilinoleic mono-, di-' and triesters of sorbitan monooleate, monoand diacid dilinoleic monoand di-esters of sorbitan dioleate, monoacid dilinoleic mono-esters of sorbitan trioleate, monoand diacid dilinoleic monoand -diesters of xylitan monooleate, mono-acid dilinoleic mono-esters of xylitan dioleate, and corresponding acid esters made from dimerized linolenic and eleostearic acids, as well as those made from partial esters of stearic acid.

The preparation of the class -of compounds useful in the compositions of the invention can be further illustrated by the following specific example:

EXAMPLE I An acid ester of a 'dimeric unsaturated fatty acid and a partial fatty acid ester of an alkitol anhydride was prepared by admixture and reaction of 428 parts by weight of sorbitan monooleate (manufactured by the Atlas Powder Company of Wilmington, Delaware, and marketed under the name Span 80) with 560 parts by weight of dimerized linoleic acid (manufactured by Emery Industries, Inc. of Cincinnati, Ohio, and marketed under the name of Emery 955 Dimer Acid). The reaction mixture was heated under reflux, until 18 parts by weight of water had been trapped off, the maximum temperature reached by the reaction mixture being 500 F. The dimerizedli noleic acid of this example had the following characteristics! V t v Straw-colored Physical state: Viscous liquid Molecular weight (approx.) 564 Gravity: API 13.0 Viscosity, SUS 200- F 597 Flash, C: F 510 Fire, 0 Cz F 575 Color, NPA +10 Iodine No., mod. Hanusu 83.3 Saponification No 186 Neutralization No 182 Dimer-content... (approx.) 85 Trimer and higher (approx.) 12 Monomer (approx) 3 The properties of the sorbitan monooleate were as follows: 5

Pour: F +10 Physical state, room temp viscous liquid Color, ASTM union 4.5 Water by distn: percent nil Carbon residue, conradson: percent 2.94 Neutralization value, ASTM D974-51T,

total acid No 6.15 pH value, glass-calomel electrodes 7.0 Saponification No., ASTM D9448T 149.0 Acetyl value, Gulf 433 142 Ash: percent 0.212

The product obtained in the above-described reaction was a clear, viscous liquid containing predominantly mono-acid esters of dimerized linoleic acid and sorbitan monooleate, having the following physical properties:

The acid esters of otherdimerized unsaturated fatty acids and other partial fatty acid esters of alkitol anhydrides are similarly prepared.

The amount of the acid ester employed in the composition of the invention depends upon the characteristic of the base oil as Well as upon the amounts of other additive agents present. Satisfactory results can be obtained when the amount of acid ester comprises about 0.001 to about 1.0percent by weight based on the weight of the total composition. A preferred range, however, comprises about 0.01 to about 0.2 percent by weight.

The lubricating oil compositions of this invention can contain other. additive agents if desired to improve other specific properties without deleteriously affecting the beneficial properties of the compositions. For example, pour point depressors, viscosity and viscosity index improvers, dyes, sludge inhibitors and the likecan be used. Also, if desired, the oil can contain a foam inhibitor such as organo-silicon oxide condensation products, organosilicol condensation products and the like.

The individual constituents of the composition of this invention may be added to the lubricating oil base in any order or simultaneously either per se or in the form of a mineral oil concentrate. The latter practice is sometimes desirable in order to facilitate compounding of the composition.- When a concentrate is prepared, it advantageously contains about 50 percent by weight of a mineral oil solvent. However, suitable concentrates can be prepared in which the mineral oil solvent comprises from 30 to percent by weight of the total concentrate. Thus, a valuable oil benefiting concentrate can be formed byadrnixing the herein disclosed constituents with a ,mineral oil solvent. In some instances, the oil to be improved may already contain an antioxidant such as an alkylated phenol. Thus, where the oil contains an alkyl phenol antioxidant, the concentrate'will require no alkyl phenol. The concentrate can, of course, contain other I inhibitors and the like.

fiting-concentrates will consist of about 30 to about 70 .450.15...percent by weight of amineral oihabout 20. to,about.4.0

percent by weight of dodecenyl succinic anhydride, about 10 .to about 30 percent by weight of the esterification product of sorbitan monooleate and dimerized linoleic acid, and about to about 25 percent .by Weight of coco- It will be noted from the data in TableI that the base oil, composition A, gave no protection against rusting when the test bar was subjected to procedure B .of ASTM .D665-53T. As will be further noted from .com-

amine isoamyl octyl orthophosphate. 5 positions B, C and D, severe rusting occurred when the One embodiment .of an oil benefiting concentrate, .acoil contained 1.25 percent of 2,6-diatertiary-butyl-4 rnethcording to this invention, for use in an oil already ccnylphenol and up to 0.1 percent of dodecenyl succinic antaining an alkylated phenol consists of about 30 percent y AS The dodecenyl .SuCCiIiiC sanhydfide was by weight of dodecenyl succinic anhydride, 20 percent by creased in compositions .E and F the amount of rusting Weight of dimerized linoleic acid-sorbitan monooleate decreased; however, the neutralization value of the oil acide ester reaction product, 11 percent by weight of increased to an undesirable level. When cocoamine isococoamine isoamyl octyl orthophosphate and 39 percent amyl octyl orthophosphate and the dimerized .linoleic by weight of a mineral lubricating oil solvent. acid sorbitan monooleate acid ester reaction product were A suitable mineral oil solvent has the following typical added to the base oil containing 2,6-di-tertiary-butyl-4- properties. 15 methylphenol the composition (composition G) had improved rust inhibiting characteristics over "the base oil y, APT but rusting was not completely eliminated. It will be Viscosity, SUS: noted from composition H, which illustrates a compo- 100 F 205 sition'of the invention, that the rusting was completely 210 F V 4.6.8 eliminated even though the cocoamine isoamyl octyl or- Vi ity index --1- 98 thophosphate, the dimerized linoleic acid-sorbitan mono- Fash Po 0C3 oleate acid, and the dodecenyl succinic anhydride were Fire p F --.--,.-.,-u 420 present in amounts less than had been used when testing P rp n .-.s-s-. 1 5 the individual constituents. The strikingly superior re- ASTM n Qn-.-.-.-.- 2.25 sults .obtained with the combination of additives are un- Nelltfalization value, ASTM D974-53T 0.02 expected in view of the results obtained with the additives individually. It is thus apparent that the additives The advantages obtained when using the improved are acting cooperatively in giving a result which is greater lubricating composition of the invention as compared than the sum of their respective properties. with the base oil and the base oil containing less than Compositions G and H were prepared by incorporating all of the addition agents are illustrated by the followan oil benefiting concentrate into the base oil to which ing specific examples. In these examples, theimproved 1.25 percent of ,2 ,6,-di-tertiary-butyl-4-methylphenol had rust inhibiting properties of the lubricating composition previously been added.. The oil benefiting concentrate have been demonstrated .by subjecting the various oil used to prepare composition G consisted of about 30 compositions to ASTM test for rust-preventing ch'aracpercent by weight .of the esterification product of sorbiteristics of steam-turbine oil in the presence of water, tan monoolea'te and dimerized linoleic acid, 20 percent D665-53T, procedure B. In brief, the test involves placby weight of cocoamine isoamyl octyl orthophosphate and ing a 300 milliliter sample of the oil in a 400 milliliter 50 percent by weight of a mineral lubricating oil having beaker which is, in turn, immersed in a constant teman API gravity of about 30 and a viscosity of about 205 perature bath maintained at a temperature of 140 F. 40 SUS at 100 F. The beaker is fitted with a cover provided with openings In preparing composition H, an oil benefiting confora stainless steel motor-driven stirrer, and for insercentrate was first prepared by admixing 30 percent by tion of a standard steel test bar which has been carefully Weight of dodecenyl succinic anhydride, 20 percent by cleaned and polished according to procedure prescribed weight of the esterification product of sorbitan monoby the ASTM test. The stirrer is started and when the oleate and dimerized linoleic acid, 11 percent 'by eight oil sample in the beaker reaches a temperature of 140 of cocoamine isoamyl octyl orthophosohate and 39 per- F., the test bar is lowered through the proper opening cent by weight of a mineral lubricating oil having an and is suspended from the beaker cover. After '30 min- API gravity of about 30 and a viscosity of about 205 utes, 30 milliliters of synthetic sea water is introduced SUS at 100 F. into the bottom of the beaker. Stirring is then contin The make-up and properties of a typical oil benefitued for 24 hours with the temperature maintained at ing concentrate of the invention are given in Table H. 140 F. At the end of this period, the steel bar is removed and examined for rust spots. v Table In making the comparative tests a base oil having an API gravity of 32.7 was used. This oil had a viscosity Composition, percent by weight: of about 153 SUS at 100 F. The oil in each instance Cocoamine isoamyl octyl orthophosphate 8.9 also contained about 0.0001 percent by weight of Dow- Dimerized linoleic acid-sorbitan monooleate Corning Silicone Fluid 200 as a foam inhibitor. ester reaction product of Example I 13.3 The results obtained in the foregoing test are presented Dodecenyl succinic anhydride 27.8 in Table I. Paraflinic mineral oil (ZOO/2.5) 50.0

Tablel Composition, Percent by Weight A B O D E F G H Base 011 100 98.73 98.70 98. 98.55 98.45 98.65 98.68 26-di-tertlary-butyl4-methylphenol. 1.25 1.26 1.2 1.25 1.25 1. 25 1.25

ocoamine isoamyl octyl orthoph p e 0.02 0.01 Dimerized linoleic acid-sorbitan monooleate acid ester reaction product of Examplel 0.08 0.02 Dodeceuylsucciuic anhydrtde 0.02 0.05 0.1 0.2 0.3 0.04 Inspection: I v

ASTM D 665-523 T Proce'dure B,

Percent Rust... 100 100 100 25 15 40 0 Neutralization Value ASTM D 7 Table -Il.Continued Inspection:

Gravity: API 21.3 Viscosity, SUS:

210 F 59.4 Viscosity index 86 Flash point, C, F 360 Fire point, 0C, F 400 Pour point, F +5 Color, ASTM union 3.25 Neutralization value ASTM D974-53T 84.0

Saponification No. ASTM D94-52T 140.9

That the properties of the base oil to which an oil benefiting concentrate of this invention has been added are not deleteriously affected can be shown by compar ing the properties of composition A with composition H. The properties of these composition-s are given in Table III.

The improved characteristics of a composition of the invention, composition H, over the characteristics of the base oil, composition A, are shown in Table IV. The film tenacity test reported in the table, like the other rust preventive tests, is designed to evaluate corrosion resistance of the film of the oil composition as applied to steel surfaces. It is carried out immediately after the ASTM D665-47T, procedure A. If the steel bar used in the ASTM test shows no evidence of rusting, it is suspended in the mouth of a 300 milliliter flask and is allowed to drain. The beaker containing the oil sample is removed from the constant temperature bath and is replaced with a clean beaker containing 300 milliliters of distilled water. With the stirrer operating, the temperature of the water in the beaker is allowed to reach 140 F. When the test bar has drained for a period of 30 minutes, it is inserted in the beaker as above. Stirring is continued for 24 hours, after which the test bar is removed and examined for rust spots.

It will be seen that this test is quite drastic, since throughout its operation the steel test bar is protected from the rust only by a thin residual film of the oil being tested. It not only evaluates the protection against rusting provided by the composition, but also indicates the tenacity with which a film of the composition adheres to the metal surface.

Table IV Properties Composition Composition Rug tglreventive Test ASTM D 665- Procedure A Steel Rod: Appearance rusted bright-passes. Area Rusted: Percent 100 0. Film Tenacity Test, 24 hr:-

Steel Rod: Appearance; bright-passes. Area Rusted: Percent 100 0. Procedure B Steel Rod: Appearance rusted bright-passes. Area Rusted: Percent 100 0. Neutralization Value ASTM D 974- 53T 0.02-- 0.15. Oxidation Test ASTM D 943-47 T:

After 1,000 hrs. Oxidation, Appearcompletely bright-passes.

ance of Coil. rusted. Hours to give 2.0 Acid No 240 2,460.

It will be noted from the data in the above table that composition H has strikingly superior properties not only with respect to rust protection but also with respect to oxidation stability.

The conditions of ASTM D943-47T are such as to approximate the conditions to which a lubricating oil is subjected in circulating lubricating systems of large capacity wherein the lubricant becomes contaminated with water. Briefly, the test comprises subjecting 300 milliliters of the lubricating oil sample to a flowing stream of oxygen in the presence of 60 milliliters of water and an iron-copper catalyst and determining the time required for the acidic oil oxidation products to build up to a neutralization value (acid number) of 2.0. The flow of oxygen is maintained at 3 liters per hour. It has been recognized in the art that lubricating oils in which the amount of acidic organic oxidation products is greater than that represented by an acid number of 2.0 are no longer serviceable because of corrosivity, the formation of sludge and stable emulsions and the general deterioration'of lubricating qualities.

It is to be noted that during the course of the test, the flowing stream of oxygen intimately mixes the oil and water layers, thus resembling the conditions encountered in lubricating steam turbines, paper mill rolls, etc. The iron and copper catalyst metals represent the metals normally found in industrial machinery and simulate the catalytic deteriorating influences of these metals on the oil in the presence of water and oxygen. The increased length of time required before composition H gives an acid number of 2.0 is indicative of the superior properties of a composition of the invention.

While the invention has been described above with reference to certain specific embodiments thereof by way of illustration, it is to be understood that the invention is not limited to such embodiments except as hereinafter defined in the appended claims.

We claim:

1. An improved lubricating composition consisting essentially of a major proportion of a mineral lubricating oil and minor proportions consisting of about 0.1 to about 5.0 percent by weight of an alkyl phenol, said alkyl phenol containing at least one alkyl group containing between 3 and 12 carbon atoms, about 0.001 to about 1.0 percent by weightof a substantially neutral addition product of 3-methylbutyl,Z-ethylhexyl acid orthophosphate and a primary fatty amine, said amine being a mono-alkyl amine containing from 8 to 18 carbon atoms, about 0.01 to about 0.3 percent by weight of an alkenyl-substituted succinic acid anhydride wherein the alkenyl group contains from 5 to 18 carbon atoms, and about 0.001 to about 1.0 percent by weight of an acid ester of (l) a dimeric acid derived from an unsaturated fatty acid containing 18 carbon atoms and having from 2 to 3 ethylenic linkages per molecule and (2) a partial ester of a fatty acid containing 18 carbon atoms and a hexitol anhydride.

2. An improved lubricating composition consisting essentially of a major proportion of a mineral lubricating oil and minor proportions consisting of about 0.1 to about 5.0 percent by weight of an alkyl phenol, said alkyl phenol containing at least one alkyl group containing between 3 and 12 carbon atoms, about 0.001 to about 1.0 percent by weight of the cocoamine salt of 3-methylbuytl, 2-ethylhexyl acid orthophosphate, about 0.01 to about 0.3 percent by Weight of an alkenyl-substituted succinic acid anhydride wherein the alkenyl group contains from 8 to 12 carbon atoms, and about 0.001 to about 1.0 percent by weight of an acid ester of (1) a dimeric acid derived from an unsaturated fatty acid containing 18 carbon atoms and having from 2 to 3 ethylenic linkages per molecule and (2) a partial ester of a fatty acid containing 18 carbon atoms and a hexitol anhydride.

3. An improved lubricating composition consisting essentially of a major proportion of a mineral lubricating oil and minor proportions consisting of about 0.1 to about 5.0 percent by weight of a tertiary alkyl phenol, said tertiary alkyl phenol containing at least one. alkyl group containing between 3 and 12.c arbon atoms, about r00l to about 1.0 percent by weight of the cocoamine salt of 3-methylbutyl,2-ethylhexyl acid orthophosphate, about 0.01 to about 0.3 percent by weight of dodecenyl succinic anhydride, and about 0.001 to about 1.0 percent by weight of an acid ester of a dimer of linoleic acid and sorbitan monooleate.

' 41. An improved lubricating composition consisting essentially of a major proportion of a mineral lubricating oil and minor proportions consisting of about 0.1 to about 5.0 percent by weight of 2,6-di-tertiary-butyl-4- methylphenol, about 0.001 to about 1.0 percent by Weight of the cocoamine salt of 3-methy1butyl,2-ethylhexyl acid orthophosphate, about 0.01 to about 0.3 percent by weight of dodecenyl succinic anhydride, and about 0.001 to about 1.0 percent by weight of an acid ester of a dimer of linoleic acid and sorbitan monooleate.

5. An oil benefiting concentrate consisting of about 30 to about 70 percent by weight of a mineral oil, about 20 12 to about 40 percent by weight of dodecenyl succinic anhydride, about 10 to about 30 percent by weight of the esterification product of sorbitan monooleate and dimerized linoleic acid, and about 5 to about/ percent by weight of cocoamine isoamyl octyl orthophosphate.

6. An oil benefiting concentrate consisting of about 39 percent by weight of a mineral oil, about'30 percent by weight of dodecenyl succinic anhydride, about 20 percent by weight of the esterification product of sorbitan monooleate and dimerized linoleic acid, and about 11 percent by weight of cocoarnine isoamyl octyl orthophosphate. 7

References Cited in the file of this patent UNITED STATES PATENTS 2,371,656 Smith et al- Mar. 20, 1945 2,398,193 Sharp Apr. 9, 1946 2,442,672 Fuchs et a1 June 1, 1948 2,631,979 McDermott Mar. 17, 1953 2,715,108 Francis Aug. 19, 1955

Claims (1)

1. AN IMPROVED LUBRICATING COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL AND MINOR PROPORTIONS CONSISTING OF ABOUT 0.1 TO ABOUT 5.0 PERCENT BY WEIGHT OF AN ALKYL PHENOL, SAID ALKYL PHENOL CONTAINING AT LEAST ONE ALKYL GROUP CONTAINING BETWEEN 3 AND 12 CARBON ATOMS, ABOUT 0.001 TO ABOUT 1.0 PERCENT BY WEIGHT OF A SUBSTANTIALLY NEUTRAL ADDITION PRODUCT OF 3-METHYLBUTYL,2-ETHYLHEXYL ACID ORTHOPHOSPHATE AND A PRIMARY FATTY AMINE, SAID AMINE BEING A MONO-ALKYL AMINE CONTAINING FROM 8 TO 18 CARBON ATOMS, ABOUT 0.01 TO ABOUT 0.3 PERCENT BY WEIGHT OF AN ALKENYL-SUBSTITUTED SUCCINIC ACID ANHYDRIDE WHEREIN THE ALKENYL GROUP CONTAINS FROM 5 TO 18 CARBON ATOMS, AND ABOUT 0.001 TO ABOUT 1.0 PERCENT BY WEIGHT OF AN ACID ESTER OF (1) A DIMERIC ACID DERIVED FROM AN UNSATURATED FATTY ACID CONTAINING 18 CARBON ATOMS AND HAVING FROM 2 TO 3 ETHYLENIC LINKAGES PER MOLECULE AND (2) A PARTIAL ESTER OF A FATTY ACID CONTAINING 18 CARBON ATOMS AND A HEXITOL ANHYDRIDE.