US2902499A

US2902499A - New chemical compounds and mineral oil compositions containing the same

Info

Publication number: US2902499A
Application number: US503006A
Authority: US
Inventors: Ralph I Gottshall; Jr Raymond T Kern
Original assignee: Gulf Oil Corp
Current assignee: Gulf Oil Corp
Priority date: 1955-04-21
Filing date: 1955-04-21
Publication date: 1959-09-01
Anticipated expiration: 1976-09-01

Description

United States Patent O NEW CHEMICAL COMPOUNDS AND MINERAL OIL COMPOSITIONS CONTAINING THE SAME No Drawing. Application April 21, 1955 Serial No. 503,006

7 Claims. (Cl. 260-4045) This invention relates to new chemical compounds and mineral oil compositions containing the same. More particularly, the invention relates to certain acidic condensation products of maleic acid and maleic anhydride and dimers of dienoic and trienoic fatty acids, and to, oilsoluble amine salts, amides, and esters of said condensation products. The invention also includes processes of preparing the foregoing condensation products and derivatives, and mineral oil compositions of improved corrosion inhibiting characteristics, having incorporated therein the aforesaid acidic condensation products and oilsoluble amine salt, amide and ester derivatives of the said acidic condensation products.

As is well known in the art, uncompounded mineral oils are often deficient in one or more respects for the particular use to which they are put. For exam le, a high resistance to rust or corrosion is important in the case of fuels or lubricants which contact metal surfaces in the presence of water. Failure to provide suflicient resistance to rust or corrosion by a particular mineral oil may result in extensive wear or damage to costly, finely machined moving parts and/or damage to storage and transport facilities and the like. To overcome this and other deficiencies of uncornpounded mineral oils, various agents known as addition agents, additives or improvement agents are incorporated in many mineral oils. Fuels or lubricants for internal combustion engines and for gas or steam turbines are examples of materials which desirably may have incorporated therein additives or improvement agents which impart corrosion inhibiting properties thereto.

We have found that the corrosion and/or rust inhibiting characteristics of mineral oils can be markedly improved by the incorporation therein of small amounts of the herein-described acidic condensation products and certain oil-soluble amine salts, amides and esters thereof. The class of acidic condensation products, or adducts, embraced by the invention includes the acidic condensation products of (a) maleic acid or maleic anhydride and (b) dimeric acids derived from unsaturated fatty acids that contain 6 to 22 carbon atoms and 2 to 3 ethylenic linkages per molecule. The oil-soluble organic deriva- .tives of the foregoing acidic condensation products included by the invention are members selected from the group consisting of (a) amine salts, and amides of the foregoing acidic condensation products and aliphatic monoarnines containing 8 to 22 carbon atoms per molecule, and (b) esters of monohydric alcohols containing 8 to 22 carbon atoms per molecule and said acidic condensation products. The present invention additionally ice 2 includes processes of preparing the foregoing products and mineral oil compositions containing at least one member of the above-indicated class of products, in' a minor, corrosion-inhibiting amount.

The particular manner in which the herein disclosed reaction products of this invention function to inhibit corrosion has not been definitely established, and for this reason the invention is not limited to any particular theory of operation. Presumably, however, the reaction products of this invention function by formation of a protective, adsorbed film of oriented molecules upon metallic surfaces contacted thereby.

The acidic condensation products of this invention can be prepared as such in any suitable manner. For example, they can be prepared using the procedure customarily resorted to in making the well-known Clocker adducts" from ordinary nonconjugated unsaturated fatty acids and maleic acid or maleic anhydride; According to one preferred procedure, the unsaturated acidic condensation products that form the nuclei of the oil-soluble amine salts, amides and esters of this invention can be formed by condensing maleic acid, or preferably the corresponding anhydride, and a dimer of a diethenoic or a triethenoic fatty acid in approximately theoretical reacting proportions at an elevated temperature. The theoretical reacting proportions are determined on the basis of the number of olefinic linkages in the dimer acid. For example, one mol of a dimeracid containing two ethylenic linkages per molecule, e.g., dimerized linoleic acid, can be condensed with one to two mols of maleic anhydride, and one mol of the dimer of linolenic acid can be condensed with one to three mols of maleic anhydride. Acidic condensation products prepared from substantially equimolar proportions of maleic acid and dimerized unsaturated fatty acid are considered especially useful for the purposes of this invention. Elevated temperatures of about 250 to about 500 F. can be used in carrying out the condensation reaction, but some deviation from these rate of reaction and of minimizing side reactions. For

example, excellent results have been obtained at temperatures of about 350 F. The reaction can usually be carried substantially to completion in a period of about 30 minutes to about 3 hours, depending upon the specific reactants and reaction temperature employed. Little advantage will be obtained by the use of longer reaction periods.

The dimeric acids and the maleic acid or anhydride disclosed herein condense with one another intermediately in the carbon chain of the respective reactants in such a manner that the carboxylic or .dicarboxylic anhydride portion of the respective reactants is not altered. The product of the abovedescribed condensation reaction is therefore a polybasic condensation product. While the exact mechanism of the condensation ofidimerized unsaturated fatty acids and maleicacid or an"- hydride has not been fully established, it appears likely that during the condensation reaction, the maleic acid or 3' anhydride becomes saturated by transfer of a hydrogen atom, perhaps from a carbon atom involved in a double bond in the dimer acid, but more probably from a carbon atom adjacent to one involved in a double bond, to either the alpha or beta carbon atom of the former, and by attachment of the remaining monovalent dimer acid radical to the alpha or beta carbon atom that did not add the hydrogen atom. The product of such an addition is a dimer acid-substituted succinic acid or anhydride. For example, a condensation product of one mol of'maleic anhydride and one mol of dimerized linoleic acid might have any of the following structural formulas:

(c) CHACHzh-CHCH-CH=CH(CH2)1C0OH Oil-soluble amine salt, amide and ester organic derivatives of the acidic adducts of this invention can be obtained in any'suitable manner. According to a preferred procedure, the oil-soluble amine salt, amide and ester derivatives of the acidic condensation products disclosed .herein are obtained by reaction of at least one member .of the group consisting of aliphatic monohydric alcohols containing 8 to 22 carbon atoms per molecule and aliphatic monoamines containing 8 to 22 carbon atoms per molecule with one of' the above-described acidic con- .densation products of a dimeric acid and maleic acid or anhydride in a mol ratio ranging from one mol of the alcohol or amine per mol of acidic condensation prod- 'maleic anhydride and one mol of dimerized linoleic acid.

Where more than one carboxyl group of the acidic condensation product of a dimeric acid and maleic acid is to be neutralized, it is not necessary that they be neutralized with the same member; for example, partly neutral and neutral mixed ester-amine salt and ester-amide derivatives of the class disclosed are specifically included by the invention.

The reaction conditions utilized in obtaining the partly :or incompletely neutral and neutral amine salt, amide and ester derivatives of the acidic condensation products disclosed herein are those conventionally used for amidation, esterification, and amine salt formation, and consequently, these conditions form no part of the invention. Thus, esterification can be effected at temperatures of about 250 to about 500 F. with temperatures of about 300 to 400 F. being preferred. The esterification reaction is normally substantially complete after about 30 minutes to 3 hours, depending on the particular reactants and the reaction temperature. Esterification can be facilitated by the use of conventional esterification catalysts. For example, sulfuric acid and p-toluene sulfonic acid can be used as catalysts. The alcohols disclosed herein appear to react preferentially with the carboxyl groups of the acidic condensation products of this invention, since esterification Will take place, to the extent possible, with the elimination of water, in a number of mols corresponding to the number of mols of alcohol that are reacted.

Amidation of the acidic condensation products disclosed herein with an amine, using a 1:1 mol ratio, can be effected over a wide range of temperatures, temperatures of about 180 F. to about 500 F. being satisfactory when the acidic condensation product is in the form of an acidic anhydride. Higher temperatures, e.g., about 300 to 450 F., preferably at least about 350 B, should be used when the acidic condensation product is not in the form of an anhydride, or where the latter is being reacted with more than one mol of amine to form a polyamidated product. The amidation is usually substantially complete in about 30 minutes to 3 hours, depending upon the particular reactants and the reaction conditions.

The amines disclosed herein appear to react preferentially with the acid anhydride group of the condensation products of this invention. Thus, for example, two mols of cocoamine will react with a 1:1 condensation product of dilinoleic acid and maleic anhydride at a temperature of 350 'F. and above to form a diamide, with the elimination of only one mol of water.

In the case of mixed ester-amide derivatives, it is not necessary to carry out the esterification and amidation independently, and both reactions can be efifected simultaneously. Nor is it necessary that the esterification and/or amidation reaction be carried out independently .from the condensation reaction involving the maleic acid elevatedtemperatures, but the speed of the reaction can usually be accelerated. appreciably by the use of heat of about 180 to about 325 F. Temperatures above about 325 F. are to be avoided, since such temperatures are conducive to amide formation rather than salt formation. Whereanacidic anhydride group is present in the acidic condensation product the temperatures specified tend to promote the formation of amides rather than amine salts.

In all of. the amine salt, amide and ester derivatives of the condensation products discussed above, the total number of mols of amine and/or alcohol used in the amidation, esterification and/or salt formation reactions with the acidic condensation product of the dimerized ethenoicfatty acid and the maleic acid or anhydride, will be the sarne or less than the product of the number of mols of the acidic condensation product and the number of carboxyl groups per molecule of said acidic condensation products. For example, in the case of a partly neutral derivative of an acidic condensation product formed by the "partial neutralization of one mol of the potentially tetracarboxylic 1:1 mol ratio condensation product of 5 maleic acid or anhydride and dimerized linoleic acid with a 4, aliphatic monoamine, e.g., lauryl amine, and/or a C;; aliphatic monohydric alcohol, e.g., lauryl alcohol, the number will be less than 4, e.g., 1, 1.5, 3, or the like.

If desired, the amine salts, amides and esters of the neutral acidic condensation products of this invention can be prepared by effecting the esterification, amidation, and/ or salt-forming reactions in mineral oil dispersion. This expedient is often of advantage in that better-control of the reaction is achieved. Moreover, the resulting amine salt, amide or ester derivatives of the acidic condensation products of this invention are in the form of mineral oil concentrates that can be added as such as to the mineral oil compositions of this invention; Alternatively, the herein disclosed acidic condensation] products and the amine salt, amide and ester derivatives thereof can be prepared as such and subsequently diluted with mineral oil or other solvent, toform. additive concentratesi Alpha,-beta ethylenic dicarboxylic acids or anhy'drides that are suitable for condensation the dimerized diand tri-ethenoic fatty acids disclosedhereiri are maleic acid and maleic anhydride. Except where otherwise indicated, the term acid and the like, as used in connection with maleic acid and acid condensation products thereof with dimers of di and tri-ethenoic fatty acids, is intended to include the corresponding acid anhydrides. Dimerized diand tri-ethenoic fatty acids" capable of forming acidic condensation products with maleic acid or varih'ydride are prepared from. monomeric: dior tri-olefinic fatty acids having the. generic" formula C H COOH, where n is an integer of 5 to 21 and x is 3 or 5. As will be evident such monomeric acids conmm 6 to 22 carbon atoms and will contain 2 or 3 ethylenic linkages per molecule as the ratioof carbon to hydrogen increases, i.e., as x increases from 3 to 5. Dimerized acids corresponding to the addition products of the foregoing acids can therefore be defined by the generic formula:

where n is an integer of 10 to 42 and xis aneven integer of 6 to 10. These dimeric acids are therefore dibasic, i;e., dicarboxylic, acids having 12 to 44 carbon atoms per molecule. The method of preparing dimeric acids is conventional and forms no part of this invention.

Dimers derived from monomeric dienoic acids that have 18 carbon atoms, especially those having conjugated olefinic linkages, are preferred for reasons of economy, ease of dimerization of the monomers and the general excellence of the amine salt, amide and ester derivatives of the acidic condensation products prepared from such dimers. A specific example of a preferred dimer acid is dimerized linoleic acid, i.e., dilinoleic acid. Examples of other dimerized acids that form suitable acidic condensation products with maleic acid for the purposes of this invention are dimers of dienoic acids such as sorbic (hexadienoic), humoceric (nonadecadienoic) and eicosenic (eicosadienoic) acids, and dimers of trienoic acids such as linolenic andeleostearic (octadecatrienoic) acids.

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

Alcohols that form suitable esters with the acidic condensation products of dimerized diand triethenoic fatty acids and 'male icacid, for the purposes of; this invention,

are aliphatic monohydric alcohols containing atleast 8 and preferably 8 to 22 carbon atoms per molecule, Whether saturated or unsaturated. Aliphatic monohydric alcohols containing at least 12 and preferably 12 to 18 carbon atoms per molecule are especially suitable for the purposes of this invention. An example of a preferred aliphatic monohydric alcohol is lauryl alcohol. Other alcohols, the use of which is included by the invention, are n-octyl alcohol, capryl alcohol, 2-ethylhexyl alcohol, stearyl alcohol, myristyl alcohol, cetyl alcohol, oleyl alco 1101 and C and higher Oxo-process branched chain alcohols. t

Amines capable of forming suitable amides and/or amine salts with the acidic condensation. products of this invention, or the partly esterified derivatives thereof, are aliphatic monoamines containing at least 8 and preferably 8 to 22 carbon atoms per molecule. The use of primary, secondary and tertiary amines, having straight or branched carbon chains, is included by the invention. Primary amines containing at least 12 and preferably 12 to- 18 carbon atoms per molecule are preferred. A specific example of a preferred amine is lauryl amine. Examples of other amines, the use of which is included by the present invention, are n-octyl amine, t-octyl amine, myristyl amine, n-hexadecyl amine, t-dodecyl amine, t-hexadecyl amine, stearyl amine, oleyl amine and n-docosyl amine.

It is not necessary that individual amines or alcohols be employed, and commercial mixtures, for example, such as can be derived from naturally occurring fats and oils, can be used. In such instances the amine or alcohol mixtures will contain primary straight chain aliphatic monofunctional amines or alcohols containing'S to 22 carbon atoms. Cocoamine and Lorol, derived from coconut oil fatty acids, are respective examples of suitable commercial amine and alcohol mixtures. These materials are respectively mixtures of C alkyl monoamines and monohydric alcohols containing even-numbers of carbon atoms, the principal components of which are lauryl amine and lauryl alcohol, respectively.

Specific examples of preferred acidic condensation products and oil-soluble organic derivatives thereof included by this invention are the 1:1 mol ratio condensation product of maleic anhydride and the dimer of linoleic acid, the dilauryl ester of the 1:1..mol ratio condensationproduct of maleic anhydride and the dimer of linoleic acid, the mono-lauryl amide of the 1:1 mol ratio condensation product of maleic anhydride and the dimer of linoleic acid, the mono-, di-, and tri-lauryl amine salts of the mono-lauryl amide of the 1:1 mol ratio condensation product of maleic anhydride and the dimer of linoleic acid, the mono-cocoamide of the monoand di-lauryl esters or" the 1:1 mol ratio condensation product of maleic anhydride and dimerized linoleic acid, and the pentalauryl ester of the 1:2 mol ratio condensation product of maleic anhydride and dimerized linoleic acid.

Specific examples of other partly neutralized acidic adducts included by the invention are the tn'lauryl ester, the dilauryl amide, the trilauryl amide, and the mixed monolauryl amide-monolauryl ester of the 1:1 mol ratio condensation product of maleic acid or anhydride and the dimer of linoleic acid. Other acidic condensation products and oil-soluble derivatives included by the invention are the 1:2 mol ratio condensation products of maleic anhydride with dimers of linoleic, linolenic, and eleostearic acids, the 1:1 mole ratio condensation products of the foregoing alpha, beta ethylenic dicarboxylic acids and anhydrides with dimers of linolenic and eleostearic acids,

nets and neutral or partly neutraL oil-soluble organic derivatives thereof, within the scope of this invention.

Example I According to this example an oil-soluble ester of an acidic condensation product according to this invention was prepared by admixing one mol of dimerized linoleic acid and one mol of maleic anhydride in a reaction vessel and heating the mixture for about two hours at about 350 F. to product a 1:1 mol ratio acidic condensation product of dimerized linoleic acid and maleic anhydride. The reaction mixture was then cooled to about 190 F., and two mols of lauryl alcohol were added. This mixture was then heated to about 340 F. and maintained at or above this temperature for about 40 minutes, approximately two rnols of water being trapped off. The dimerized linoleic acid employed in this example was a commercial product (Emery 955 Dimer Acid, Emery Industries, Inc., Cincinnati, Ohio), consisting mostly of the dimer of 9,11-octadecadienoic acid:

The commercial dimer acid has the following typical inspections Physical state viscous liquid Molecular weight (approx) 600 Iodine value 80-95 Acid value 180-192 Saponification value 185-195 Unsaponifiable 2.0% max. Color, Gardner 12 max. Neutralization equivalent 290-310 Dimer content, percent (approx.) 85

Trimer content, percent (approx.) 12 Monomer content, percent (approx) 3 Refractive index at 25 C. 1.4919 Specific gravity at 15.5 C./15.5 C 0.95

Flash point, F 530 Fire point, F 600 Viscosity at 100 C., centistokes 100 The product of the above-described reactions consisted essentially of the dilauryl ester of the 1:1 mol ratio condensation product of maleic anhydride and dilinoleic acid. This product was a semi-solid material having a grayish color.

Example 11 ,this reaction consisted essentially of the mixed monococoamides of the 1:1 mol ratio condensation product of dilinoleic acid and maleic anhydride. The predominant component of the mixed monococoamides was the monolauryl amide. The product of the reaction was a brown- Zish solid.

Example 111 i h A monoamine salt of a monoamide of an acidic condensation product according to this invention was preacidic condensation product.

pared similarly as in Example H, except that two mole of cocoamine were employed. The product of this reaction was also a brownish solid and consisted essentially of the mono-cocoamine addition salt of the monococoamide of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride. The prin cipal component of the mixed product was the monolauryl amine addition salt of the mono-lauryl amide of the above-indicated condensation product.

Example IV Another amine salt-amide derivative was prepared as in Example II, except that three mols of cocoamine were employed in the reaction. The product of this reaction was also a brownish solid consisting essentially of the di-cocoamine addition salt of the mono-cocoamide of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride. The principal component of the-mixed salts was the di-lauryl amine salt of the monolauryl amide-ofsaid condensation product.

Example V Example VI Another oil-soluble derivative according to this invention was prepared by reacting one mol of the dimerized linoleic acid described in Example I with two rnols of maleic anhydride at 350 F. for about three hours, to form a 1:2 mol ratio acidic condensation product of dimer acid and maleic anhydride. At the completion of this period the temperature of the reaction mixture was allowed to drop to 200 F., and enough cocoamine was added to bring the pH up to 7 (approximately 1.7 rnols were required). The resulting product was then waterwashed and heated to 285 F. to dry. The product, a tan solid, was the mixed monoand dicocoamides of the 1:2 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

Example VII Another ester derivative of an acidic condensation product disclosed herein was prepared by reacting one mol of the dimerized linoleic acid described in Example I with two mols of maleic anhydride at a temperature of 350 F. for about two hours, to form a 1:2 mol ratio The reaction mixture was then cooled to about F. and five mols of lauryl alcohol were added thereto. The temperature of the mixture was then raised to 340 F. and maintained at or above this point with refluxing, until about three rnols of water had been trapped CE. The product of this reaction was a semi-solid material having a grayish color, and it consisted essentially of the pentalauryl ester of the 1:2 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

Example VIII Example I with one mol of maleic anhydride at about maleic anhydride.

9 350 F. for about two hours, to form a 1:1 mol ratio acidic condensation product. This condensation product was then cooled to 190 F. and two mols of lauryl alcohol were added. The resulting mixture was then heated to 350 F. under reflux and maintained at this point or above until two mols of water were trapped off, thus forming a dilauryl ester of the 1:1 mol ratio acidic conden- Example IX According to this example 0.7 mol of each of (a) maleic anhydride, (b) the dilinoleic acid described inExarnple I and (c) lauryl alcohol, were reacted at 340 -500" F. for

two hours to form the monolauryl ester ofthe 1:1 mol ratio condensation product of dimerized linoleic acid and The resulting reaction product was then cooled below 200 F. and 0.7 mol of cocoamine was added, and the mixture was heated to a temperature ,of about 250 F. forbetween two and three hours. The

product of this reaction, a light brown solid, was the monococoaniide of the monolauryl ester of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride. 7 e

The foregoing examples are illustrative only, and the acidic condensation products of maleic acid or anhydride and other dimeri zed diand tri-ethenoic C fatty acids, disclosed herein, and oil-soluble esters, amine salts and amides of said acidic condensation products and C prepared in substantially identical fashion.

The acidic condensation'products of this invention are useful as corrosion inhibitors and as intermediates in the preparation of the oil-soluble amides, amine salts and ester derivatives disclosed herein. Because of their relatively lower oil-solubility, it may be necessary to employ dispersants or solubilizing agents, such as alkali metal sulfonates, butyl Cellosolve (ethylene glycol monobutyl ether), butyl Carbitol (diethyleneglycol butyl ether), or the like, to obtain bright oil compositions containing the acidic condensation products. The class of amine salt, amide and ester derivatives indicated possesses superior mineral lubricating oil-solubility characteristics as compared with the acidic condensation products themselves, and for this reason the former find especial utility. By way of illustrating the lubricating oil-solubility characteristics of the acidic condensation products and their derivatives, 0.05 percent by weight of the 1:1 mol ratio acidic condensation product of dimerized linoleic acid and maleic anhydride failed to dissolve completely in the mineral lubricating oil described in Example X below, as evidenced by the hazy appearance of the oil sample. In contrast, the same amount of each of the derivativesof this acidic condensation product described in Examples I to V, inclusive, and in Examples VIII and IX dissolved completely, as evidenced by the bright or transparent appearance of the oil samples.

The neutral and partly neutral amine salt, amide and ester derivatives included by this invention can be incorporated in the desired mineral oil vehicle in any suitable manner. For example, they can be admixed with the desired mineral oil either as such or in the form of concentrated solutions or dispersions. In a preferred embodiment the amine salts, amides and esters of this invention are employed in a mineral lubricating oil, for example, a turbine lubricating oil. Examples of other mineral oil compositions which can be benefited by the incorporation therein of the amine salts, amides and aliphatic monohydric alcohols and monoamines can be esters of this invention are kerosene, gasoline, diesel fuel, furnace oil, motor oil and lubricating greases.

The acidic condensation products of this invention and the amine salts, amides, and esters disclosed herein are useful when incorporated in mineral oil compositions in minor proportions, suflicient to confer rust and corrosion inhibiting properties thereupon. For example, the acidic condensation products and the amine salts, esters and amides of this invention are useful when incorporated in mineral oil compositions in amounts of about 0.01 to 1.0 percent, the optimum amount varying with the character of the mineral oil composition and the specific nature of the reaction products. For example, good results are obtained when the acidic condensation prodnets, and especially when the amine salts, amides and esters ofthis invention are employed in mineral oils in amounts of about 0.01 percent by weight of the composition. Excellent results are obtained when the latter materials are incorporated in mineral oils in amounts of 0.025 to 0.1 percent by Weight of the composition. However, as pointed out above, up to about 1.0 percent by weight of the composition of the reaction products of this invention can be used, if desired.

The invention includes mineral oil compositions where the mineral oil vehicle is not employed as a fuel or lubricant but merely as a solvent vehicle. In suoh instances the compositions may contain substantially in excess of 1 percent by Weight of the composition of the amine salt, amide and ester derivatives of this invention. Examples of solvents that can be used in such compositions are light naphtha, mineral spirits and the like.

The specific embodiments set forth in the following example illustrate suitable mineral oil compositions included by the invention.

Example X To each of nine separate samples of a highly refined, highly parafiinic turbine lubricating oil, a typical sample of which had an API gravity of 31.7 a Saybolt Universal viscosity of 336 seconds/ 70 F., 150.5 seconds/ F., 85.2 seconds/ F. and 43.8 seconds/210 R, a viscosity index of 110, a pour point of +5 R, an ASTM Union color of less than one and a Conradson carbon residue of 0.01 percent, was added 0.05 percent by weight of one of the products prepared in specific Examples I to IX. The turbine oil base employed in the various embodiments of this example contained 1.25 percent of 2,6-t-butyl,4-methylphenol as an oxidation inhibitor, and 0.0001 percent by weight of Dow- Corning Silicone Fluid 200 (dimethyl silicone fluid) as a foam inhibitor. Neither of these materials has any apparent effect upon the corrosion-inhibiting characteristics of the base oil stock or of the acidic condensation products, amine salts, amides or esters of this invention.

The corrosion-inhibiting characteristics of the mineral oil compositions of this invention have been demonstrated by subjecting mineral oil compositions containing amine salts, amides and esters included within the scope of this invention to the standard procedure of the ASTM turbine oil corrosion test ASTM D 665-52 T, Procedure A. This test is described in ASTM Standard on Petroleum Products and Lubricants for November 1952. Briefly, this test involves immersion of a previously polished, standard steel test rod in a 300 ml. sample of the test oil, to which there is added 30 ml. of distilled water, and maintaining the test rod in contact with the agitated mixture of oil and water for 24 hours. At the end of the test period the test specimen is observed for rusting. The improvement in corrosion-inhibiting properties obtained by the use of the reaction products of this in vention was determined by comparison of the rusting obtained with a blank sample of the base turbine oil described in Example X with the results otbained with each of the inhibited test oil samples described inEx- 11 ample X. The results of the tests are presented in the following table: l r

12 has been indicated the acidic condensation products and the amine salts, amides and esters described herein can be TABLE A Bun No 1 Make-up, percent by wt.:

Base oil. 100 Dilauryl ester of 1:1 condensation product of dn'nerized liuoleic acid and maleic anhydride (Example I product)" Mono-lauryl amide of 1:1 condensation product of dimerized linoleic acid and maleic anhydride (Example Il product) Mono-lauryl amine salt of mono-lauryl amide of the 1:1 condensation product of dimerized linolelc acid and maleic auhydride (Example III product) Dilau.ryl amine salt of mono-lauryl amide of the 1:1 condensation product of dimerized linoleic acid and maleic anhydride (Example IV product) Tri-lauryl amine salt of mono-lauryl amide of the 1:1 condensation product of dimerized linoleic acid and maleic anhydride (Example V product) Mixed monoand di-lauryl amides of the 1:2 condensation product of dimerized linoleic acid and maleie anhydride (Example VI product) v Pentalauryl ester of the 1:2 ensation product of dimerized linoleic acid and maleic anhydride (Example VII product) Mono-lauryl amide of ry ester of 1:1 condensat on product of dimerized linoleic acid and maleic anhydride (Example VIII product) Mono-lauryl amide of monola tion product of dimerized linoleic acid and malelc anhydride (Example IX product) ryl ester of 1:1 condensa- Inspection:

ASTM D 665-52 T, procedure A, 24 hours rusting severe 1 trace 0 O O 0 O 0 0 0 1 Trace equals 0 rust to 1 rust spot, one ml. in diameter.

Comparison of the results obtained in test runs 2 to inclusive, with those obtained in test run 1 demonstrates the beneficial results obtained with the additives included by this invention. Similar improvement is obtainable by substitution in the foregoing embodiments in the same or equivalent proportions, or in other proportions disclosed herein, of other herein disclosed amine salts, amides and esters of other C aliphatic monoamines and/ or other C aliphatic monohydric alcohols and the condensation products of other dimerized diethenoic or triethenoic C acids and other maleic acid or anhydride.

The importance of the presence of the dimerized dior tri-etheno ic acid residues in the ultimate rust inhibiting products disclosed herein is demonstrated by comparison of the results set forth in Table A with those set forth in Table B below. in the following table the base oil referred to was the same as that used in the test oils described in Example X, and the reaction products indicated Were obtained by a procedure substantially the same as that disclosed for the additives of this invention.

TAB LE B Run No 1 2 Make-up: lfereent by Wt.:

Base 011 95.95 95.95 Mono-lauryl Amide of Monolauryl Ester of 1:1

Condensation Product of Lluoleie Acid and Maleie Anhydride 0.05 Dilauryl Ester of 1:1 Condensation Product of Oleic Acid and Malelc Anhydrlde 0.05

Inspection:

ASTM D 665-52 T, Procedure A, 24 Hours Rusting, percent 5 5 lubricants is considered particularly advantageous. As

incorporated in mineral oil solvents, such as light naphtha, which are employed neither as a fuel nor as a lubricant. In such instances the compositions find use in the coating art, wherein a metallic article subject to rust or corrosion can be brushed, dipped, or sprayed with the composition comprising the solvent and the additive. Subsequent evaporation of the solvent deposits an adherent, corrosion resisting coating of the additive upon the metal article. The acidic condensation products and the amine salts, amides and esters of this invention can also be used as corrosion inhibiting additives in paints, varnishes, automobile undercoatings and the like. In the use of the acidic condensation products and the amine salts, amides and esters of this invention in various coating compositions, it can be advantageous to employ the former in substantially greater concentrations than are normally utilized in fuels and lubricants.

While the foregoing description has in the main been directed to reaction products wherein not all of the carboxylic groups have been reacted, it will be understood that many obvious derivatives of such partly neutralized acidic condensation products can be prepared and are included by the invention. For example, there can be prepared olefin oxide derivatives, e.g., ethylene oxide and propylene oxide derivatives, derivatives of low molecular weight amines, i.e., low molecular weight amine salts and amides, e.g., methyl amine, mono-, di-, and tri-ethanol amine, alkali and alkaline earth metal salts and ammonium salts, and esters of low molecular weight alcohols, e.g., methyl, ethyl, propyl and butyl alcohols.

It is to be understood that the improved mineral oil compositions of this invention can be additionally benefited by the incorporation therein of other known improvement agents adapted to confer other desirable properties upon the composition. For example, there can be added antioxidants, viscosity index improvers, thickeners, pour point improvement agents, bearing corrosion inhibitors, detergents, dispersants, soaps, dyes, extreme pressure agents and the like. 7

Resort can be had to such modifications of the invention as do not depart from the spirit of the invention or the scope of the appended claims.

We claim: 7 r

1. A material selected from the group consisting of (I) acidic condensation products of (a) a dimeric acid derived 13 from an ethenoic fatty acid that contains 2 to 3 ethylenic linkages and 6 to 22 carbon atoms per molecule, and (b) a member selected from the group consisting of maleic acid and maleic anhydride, where the mol ratio of (a) to (b) is 1:1 to 1:2 when the dimeric acid is derived from a dienoic acid and 1:1 to 1:3 when the dimeric acid is derived from a trienoic acid and (II) organic derivatives 3 of said acidic condensation products selected from the group consisting of amine salts and amides of aliphatic monoamines that contain 8 to 22 carbon atoms per molecule and whose substituents are hydrocarbon radicals, and esters of unsubstituted monohydric alcohols that contain 8 to 22 carbon atoms per molecule.

2. The dilauryl ester of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

3. The mono-lauryl amide of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

4. The lauryl amine salt of a mono-lauryl amide of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

5. The pentalauryl ester of the 1:2 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

6. The mono-lauryl amide of a lauryl ester of the 1:1 mol ratio condensation product of dimerized linoleic acid and maleic anhydride.

7. A process comprising condensing a member selected from the group consisting of maleic acid, and maleic anhydride, with a dimeric acid derived from an unsaturated fatty acid that contains 6 to 22 carbon atoms and 2 to 3 ethylenic linkages per molecule, in a mol ratio of 1 to 2 mols of said member per mol of dimeric acid when the dimeric acid is derived from a dienoic acid and 1 to 3 mols of said member per mol of dimeric acid when the dimeric acid is derived from a trienoic acid to form an acidic condensation product, forming an oil-soluble derivative of said acidic condensation product by reacting one acidic group up to the total number of acidic groups contained in said acidic condensation product with at least one member selected from the group consisting of aliphatic monoamines containing 8 to 22 carbon atoms per molecule and whose substituents are hydrocarbon radicals and unsubstituted aliphatic monohydric alcohols containing 8 to 22 carbon atoms per molecule, under conditions such as to promote at least one reaction selected from the group consisting of amine salt formation amidation and esterification.

References Cited in the file of this patent UNITED STATES PATENTS 2,374,381 Root Apr. 24, 1945 2,426,338 Blair Aug. 26, 1947 2,630,441 Dazzi Mar. 3, 1953 2,687,421 Butler Aug. 24, 1954 2,689,828 Smith Sept. 21, 1954 2,718,503 Rocchini Sept. 20, 1955 OTHER REFERENCES Cowan et al.: Oil and Soap, August 1943, pp. 153-457.

Bailey: Industrial Oil and Fat Products, 1951, pp. 896-910.

Bailey: Oil and Fat Products, 1951, pp. 413-417, 429.