US3121057A

US3121057A - Succinamic metal salts in turbine oil

Info

Publication number: US3121057A
Application number: US72866A
Authority: US
Inventors: Paul Y C Gee; Jr Harry J Andress
Original assignee: Socony Mobil Oil Co Inc
Current assignee: ExxonMobil Oil Corp
Priority date: 1960-12-01
Filing date: 1960-12-01
Publication date: 1964-02-11
Anticipated expiration: 1981-02-11

Description

United States Patent Ofilice 3,121,057 Patented Feb. 11, 1964.-

This invention relates to antirust compositions. It is more particularly concerned with mineral lubricating oil containing metal salts of certain amic acids.

As is well known to those skilled in the art, the rusting of ferrous metal surfaces has been a common occurrence in the field of lubrication. This has been a serious problem in steam turbine lubrication, particularly during the initial operation of new installations. Rusting is most pronounced at points where the clearance between bearing surfaces is very small, as in the governor mechanism. This is usually caused by water entering the oil supply, as by condensation, and becoming entrained in the oil throughout the circulating system, thereby coming into contact with the ferrous metal surfaces. Manifestly, this constitutes a menace to the operational life of the turbine.

Many materials have been proposed as addition agents to impart antirust properties to lubricating oils. Particularly in the case of rust protection in the presence of sea water, as in marine turbine lubrication, most compounds used have been materials containing two or more carboxylic acid groups (-COOH).

It has now been found that antirust properties in the presence of sea water can be imparted to lubricating oil by the addition of certain monocarboxylic acid salts. It has been discovered that certain succinamic acid salts are effective antirust additives for turbine oils.

Accordingly, it is a broad object of this invention to provide novel rust inhibitors. Another object is to provide lubricating oils that are inhibited against rusting of ferrous metal surfaces in the presence of sea water. A further object is to provide an antirust turbine oil con taining a monocarboxylic acid salt rust inhibitor. A specific object is to provide metal salts of succinamic acids. A more specific object is to provide antirust turbine oil containing certain succinamic acid salts. Other objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description.

In general, the present invention provides a mineral lubricating oil containing a small amount, sufficient to prevent rusting of ferrous metal surfaces, selected from the group consisting of (1) group II metal salts of an amic acid having the formula,

wherein R is a monovalent alkyl radical containing between about 18 and about carbon atoms and having a tertiary carbon atom directly attached to the nitrogen atom, (2) copper salts of an amic acid having the formula,

wherein R is a monovalent alkyl radical containing between about 18 and about 30 carbon atoms and having 1 tertiary carbon atom directly attached to the nitrogen atom, and (3) methoxy group II metal salts of an amic acid having the formula,

wherein R is a monovalent alkyl radical containing between about 18 and about 30 carbon atoms and having a tertiary carbon atom directly attached to the nitrogen atom.

The addition agents utilizable in the improved lubricating oils of this invention are succinamic acid salts having the structural formula,

ii mLv-c-clncrn-o wherein R is an alkyl group containing between about 18 and about 30 carbon atoms per alkyl group and having a tertiary carbon atom directly attached to the nitrogen atom and M is a metal of group II of the periodic chart of the elements. The amic acids that are converted into the metal salts can be made by any method known in the art for preparing such compounds. Preferably, they are produced by warming succinic acid anhydride with a tertiary-alkyl primary monoamine having between about 18 and about 30 carbon atoms per molecule. This can be done readily by heating a mixture of equimolar amounts of the acid anhydride and the tertiary-alkyl primary amine at a temperature of -150 C. for a period of time varying between one and 4 hours. The addition occurs readily Without the formation of water. Lcss desirably, the amic acids can be prepared by the controlled reaction between equimolar amounts of succinic acid and the amine, with the elimination of one mole of water per mole of amie acid produced. Care must be exercised to avoid the elimination of two moles of water to form the cyclic imide.

The amines utilizable in forming the amic acids are the tertiary-alkyl primary monoamines in which a primary amino group (NH is attached to a tertiary carbon atom, and which contains between about 18 and about 30 carbon atoms per tertiary-alkyl group. The amines all contain the group,

Non-limiting examples of the amines are t-dodecyl primary amine, t-tetradecyl primary amine, t-pentadecyl primary amine, t-hexadecyl primary amine, t-0ctadecy1 primary amine, t-eicosyl primary amine, t-tetracosyl primary amine, and t-triacontyl primary amine. These amines can be prepared by several methods well known to those skilled in the art. Specific methods for preparing the t-allt'yl primary amines are disclosed in the Journal of Organic Chemistry, vol. 20, page 295 et seq. (1955). Mixtures of such amines are contemplated. These can be made from a polyolefin fraction (e.g. polypropylene and polybutylene cuts) by first hydrating with sulfuric acid and water to the corresponding alcohol, converting J the alcohol to alkyl chloride with dry hydrogen chloride, and finally condensing the chloride with ammonia, under pressure to produce a t-alltyl primary amine mixture.

The salts contemplated herein are neutral salts of copper and group H metals and the methoxy metal salts of group 11 metals. The amido portion of both neutral and incthoxy salts must have at least about 18 carbon atoms and up to about 30 carbon atoms in the alkyl group attached thereto.

The neutral salts of the succinamic acids contemplated herein are metal salts wherein the salt-forming metal is copper or from group ll (including both 11A and 11B) of the periodic chart of the elements, as set forth in Introductory College Chemistry, by H. G. Deming (Jahn Wiley and Sons). Preferred salt-forming metals are Ba, Ca, Sr, Mg, and Zn. The method of forming the metal salts of this invention is not a critical factor herein. Thus, any of the usual methods known to those skilled in the art can be utilized. Typical methods include forming an alkali-metal salt (cg. by neutralizing with caustic). and then using a double decomposition reaction with a salt of the desired metal (cg. CaCl neutralizing the acid with a metal alcoholate (cg. barium methylate); and heating with an oxide of the metal (e.g. magnesium oxide). Suitably, non-polar solvents can be used in the salt-forming operation. Thus, concentrates of the salts or" this invention in amounts varying between about 10 percent and about 90 percent, by weight, in a solvent arc contemplated. Such concentrates are then added to the turbine oil to give the desired final concentration in the lubricant. Suitable solvents are lubricating oils.

The methoxy metal salts contemplated herein are made from metals of group ll (including both HA and 11B) of the periodic chart of the elements. They can be prepared by eating equimolar amounts of the amic acid and metal methortidc (methylate). Temperatures in the order of ll50 C. are suitable for the neutralization reaction. Generally, a diluent is desirable and filtration of the product may be desired.

The antic acid salts contemplated herein are ettective to impart antirust properties to mineral lubricating oils, particularly highly refined mineral lubricating oils, such as, steam turbine oils. The amount of amic acid salt that is added to the lubricating oil will vary between about 0.001 percent and about 10.0 percent, by weight, of the oil. In preferred practice, amounts varying be tween about 0.05 percent and about 1.0 percent, by weight. are used. ()thcr substances can be added to the lubricating oil to impart other properties thereto. For example, there may be added antioxidants, pour point depressants, V.l. improvers, and El. agents.

The following specific examples are for the purpose of illustrating the antirust lubricants of this invention and of demonstrating the effectiveness thereof. It is to be understood that this invention is not to be limited to the particular reactants employed, or to the operations and manipulations described therein. Other reactants, as described hcieinbefore, can be employed, as those skilled in the art will readily understand.

The amine reactants used in the examples are a mixture or" pure amines. Amine i is a mixture of tertiary allryl primary amines averaging 18 to 24 carbon atoms per molecule and averaging about carbon atoms per molecule. it has a tertiary carbon attached to the NH group. It contains, by weight, about 4-0 percent t-octayl primary amine, about percent t-eicosyl primary airline, about 15 percent t-docosyl primary amine, about 10 percent ttetracosyl amine. and a small amount, less than 5 percent, other amines as high as t-triacontyl primary amine.

EXAMPLE 1 was stirred at 95 C. for '1 hours to form the Amir Analysis:

Estimated Found Percent Mg 1. 3-; I 1.41) Percent N 1. 7 1. 57

EXAMPLE 2 A mixture of 50 gms. (0.5 mole) of succinic anhydride, 150 gms. (0.5 mole) of Amine B and 150 cc. of xylene was stirred at C. for 2 hours to form the Amine B succinamic acid. To the above Amine B succinamic acid was added at room temperature with stirring 20 gms. (0.5 mole) NuOH previously dissolved in 200 cc. of methanol. The mixture was gradually heated to 175 C. to form the sodium salt of the Amine B succinamic acid. To the Na salt of the Amine B succinamic acid was then added 420 gms. of light lubricating oil and 33 gms. (0.25+5 grns. excess) of CaCl previously dissolved in 200 cc. of methanol. The mixture was gradually heated to l75 C. and was held there for 3 hours to insure the complete formation of the Ca salt. The reaction product was filtered through filtering clay. The final product, the calcium salt of the Amine B succinamic acid, which contains 66% light lubricating oil was fluid at room temperature.

Analysis:

1 Estimated Found lcrccnt (a 1.85 1.57 Percent N 1. 32 1. l2

EXAMPLE 3 A mixture of 50 grns. (0.5 mole) of succinic anhydride, gms. (0.5 mole) of Amine B and 150 cc. of toluene was stirred at 95 C. for 2 hours to form the Amine B succinamic acid. To the above Amine B succinarnic acid was added at 50 C. with stirring 286 gms. of 12% Ba mcthylate solution (0.25 mole of Ba). The mixture was gradually heated to C. The reaction product being viscous, was diluted with 468 gms. of light lubricating oil and filtered through filtering clay. The final product, the Bu salt of the Amine l3 succinamic acid, which contained 66% light lubricating oil was fiuid at room temperature.

Analysis:

Estimated Found Percent Ba 4. 5s 2. 33 Percent. N 0. J 0. till EXAMPLE 4 A mixture of 50 gms. (0.5 mole) of succinie anhydridc, 150 gms. (0.5 mole) of Amine B and 150 cc. of xylene was stirred at 95 C. for 2 hours to form the Amine B succinamie acid. To the above Amine l3 succinamic acid was added at room temperature with. stirring 20 gms. (0.5 mole) of NaOH previously dissolved in 250 cc. of methanol. The mixture was gradually heated to 175 C. form the Na salt of the Amine B suecinamic acid. To the Na salt of the Amine l3 t mic acid was tlrm. added at room temperature airing 432 grns. of light lubricating oil and 44 gms. (0.25 rnole+l gms. excess) of ZnCl previously dissolved in 250 cc. of methanol. The mixture was 'radually heated to 175 C. and was held at 175 C. for 3 hours to insure the complete formation of the Zn salt of the Amine B succinamic acid. The product was filtered through filtering clay. The final product which contained 66% light lubricating oil was fluid at room temperature.

Analysis:

Estimated Found Percent Zn 2. 2. 01 Percent N 1. 08 1. 08

EXAMPLE 5 A mixture of 50 gms. (0.5 mole) of succinic anhydride, 150 gms. (0.5 mole) of Amine B and 206 gms. of light lubricating oil was heated at 100 C. for 2 hours with stirring to form the Amine B succinamic acid. To the Amine B succinamic acid was added 14.6 gms. (0.25 mole) of magnesium hydroxide at room temperature with stirring. The mixture was gradually heated to 175 C. and was held at 175 C. for 30 minutes. The reaction product was filtered through filtering clay. The final product, the Mg salt of Amine B succinamic acid, which contained 50% light lubricating oil was fluid at room temperature.

Analysis:

I Estimated Found Percent Mg 1. 4 1, 28 Percent N 1. 7 1. 52

EXAMPLE 6 A mixture of 50 gms. (0.5 mole) of succinic anhydride, 150 gms. (0.5 mole) of Amine B and 206 gms. of light lubricating oil was heated at 95100 C. for 2 hours with stirring to form the Amine B sucoinamic acid. To the Amine B succinamic acid was added 10.08 gms. (0.25 mole) of magnesium oxide at room temperature with stirring. The mixture was gradually heated to 175 C. and was held at 175 C. for 2 hours. The reaction prodnot was filtered through filtering clay. The final products, the Mg salt of Amine B succinarnic acid, which contained 50% light lubricating oil was clear and fluid at room temperature.

Analysis:

Estimated Found Percent Mg 1.4 1. 24 Percent N 1. 7 1. 58

EXAMPLE 7 A mixture of 50 gms. (0.5 mole) of succinic anhydride, 150 gms. (0.5 mole) of Amine B and 100 cc. of benzene was heated at 95 C. for 2 hours with stirring to form the Amine B succinamic acid. The Amine B succinamic acid, diluted with 215 grns. of light lubricating oil, was added at room temperature with stirring to 11.5 grns. (0.5 mole) of sodium in the form of a sodium methylate solution. The mixture was gradually heated to 175 C. to form the sodium salt of Amine B succinamic acid. To the Amine B succinamic salt was added at room temperature with stirring 69 gms. (0.25 mole+6.5 gms. excess) of CuSO .5H O dissolved in 1000 cc. of methanol. The mixture was gradually heated to 175 C. and was held at 175 C. for 2 hours. The reaction product was filtered through filtering clay. The final product, the cupric salt of Amine B succinamic acid, which contained 50% light lubricating oil was dark-green in color and fluid at room temperature.

Analysis:

Estimated Found EXAMPLE 8 A mixture of 50 gms. (0.5 mole) of succinic anhydride, 150 gms. (0.5 mole) of Amino B and 100 cc. of

cnzene was heated at 95 C. for 2 hours with stirring to form the Amine B succinamic acid. The Amine B succinamic acid, diluted with 464 gms. of light lubricating oil, was then added at room temperature with stirring to the zinc methylate solution prepared from 23 gms. (1 mole of sodium in the form of a sodium methylate solution and 88 gms. (0.5 mole+20 gms. excess) of Zinc chloride dissolved in 300 cc. of methanol. The mixture, being heated gradually with stirring to distill out the methanol, started to thicken at about C. A quantity of 9 cc. of water added drop-wise made the reaction mixture fluid again. The reaction mixture was slowly heated to 150 C. and held at 150 C. for 30 minutes. The reaction product was then filtered through filtering clay. The final product, the methoxy Zinc salt of Amine B succinamic acid, which contained 66 /392; light lubricating oil was clear and fluid.

Analysis:

[ Estimated Found Percent. Zn Percent N EXAMPLE 9 A mixture of 50 gms. (0.5 mole) of succinic anhydride, 150 gms. (0.5 mole) of Amine B and 100 cc. of benzene was heated at C. for 2 hours with stirring to form the Amine B succinamic acid. The Amine B succinamic acid, diluted with 424 gms. of light lubricating oil, was then added at room temperature with stirring to 12.12 gms. (0.5 mole) of Mg in the form of a Mg methylatc solution. The mixture was gradually heated to 150 C. and was held at 150 C. until all the methanol and benzene distilled over (about 2 hours). The final product, the methoxy Mg salt of Amine B succinamic acid, which contained 66 /69?) light lubricating oil, was clear and fluid at room temperature.

Analysis:

Estimated Found EXAMPLE 10 Nine mineral oil blends were prepared. Each blend contained a small amount of one of the additives described in Examples 1 through 9. The base oil used is a highly solvent-refined mineral lubricating oil having 31 API gravity and a Saybolt Universal viscosity of 150 seconds at F. This is a typical steam turbine lubrieating oil. These blends were subjected to the ASTM rust test D665-44T using synthetic sea water. The composition of each blend and test results are set forth in Table I.

The test method used to distinguish the rusting characteristics of lubricating oil blends was the ASTM test D66544T for determining Rust Preventing Characteristics of Steam Turbine Oils in Presence of later, in which synthetic sea water was used. The synthetic sea water contained 25 grams of sodium chloride, 11 grams of magnesium chloride hexahydrate, 4 grams of sodium sulfate, and 1.2 grams of calcium chloride per liter. In this test a cylindrical polished steel specimen is suspended and soaked in 300 cubic centimeters of the oil under test at 140 F. for thirty minutes. Thirty cubic centimeters of synthetic sea water are added and the mixture is stirred at 1000 rpm. After 48 hours, the steel specimen is removed and examined for evidence of rust on the portion of the specimen which hangs in the oil. in order to pass this test, the test specimen must be entirely free of rust.

Table I l (one'n, ASTM Additive t Exarnple Wt. Hurt Test percent Result more It will be apparent to those skilled in the art that the metal salts and methoxy metal of these succinamic acids are eifective to impart antirust properties to lubricating oils, in the presence of sea water. Thus, the mineral oil compositions are highly effective for severe service, such as, in marine turbine lubrication.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

1. A mineral lubricating oil containing a small amount, based on the weight of said oil and sullicient to inhibit said oil against rusting of ferrous metal surfaces, of a metal salt selected from the group consisting of (l) wherein R is an alkyl group containing between about 18 and about 30 carbon atoms per alkyl group and having a tertiary carbon atom directly attached to the nitrogen atom and M is selected from the group consisting of copper and metals of group II of the periodic chart of the elements; and (2) wherein R is an alkyl group containing between about 18 and about 30 carbon atoms per alltyl group and having a tertiary carbon atom directly attached to the nitrogen atom and M is a metal of group It of the periodic chart of the elements.

2. A mineral lubricating oil containing between about 0.001 percent and about percent, by weight of the lubricant, of a metal salt selected from the group consisting of (1) R11NC*CII2C li2(/O ll ll wherein R is an alkyl group containing between about 18 and about carbon atoms per alkyl group and having a tertiary carbon atom directly attached to the nitrogen atom and M is selected from the group consisting of copper and metals of group 11 of the periodic chart of the elements; and (2) wherein R is an alkyl group containing between about 18 and about 30 carbon atoms per alkyl group and having a tertiary carbon atom directly attached to the nitrogen atom and M is a metal of group 11 of the periodic chart of the elements.

3. A mineral lubricating oil containing between about 0.05 percent and about 1.0 percent, by weight of the lubricant, of a metal salt having the structure,

wherein R is an alkyl group containing between about 18 and about 24 carbon atoms per alkyl group and having a tertiary carbon atom directly attached to the nitrogen atom.

4. A mineral lubricating oil containing between about 0.05 percent and about 1.0 percent, by weight of the lubricant, of a metal salt having the structure,

5. A mineral lubricating oil containing between about 0.05 percent and about 1.0 percent, by weight of the lubricant, of a metal salt having the structure,

6. A mineral lubricating oil containing between about 0.05 percent and about 1.0 percent, by weight of the lubricant, of a metal salt having the structure,

7. A mineral lubricating oil containing between about 0.05 percent and about 1.0 percent, by weight of the lubricant, of a metal salt having the structure,

8. A mineral lubricating oil containing between about 0.05 percent and about 1.0 percent, by weight of the lubricant, of a metal salt having the structure,

wherein R is an alkyl group containing between about 18 and about 24 carbon atoms per alkyl group and having a 9 tertiary carbon atom directly attached to the nitrogen atom.

9. A mineral lubricating oil containing between about 0.05 percent and about 1.0 percent, by weight of the lubricant, of a metal salt having the structure,

RlIN|(|2CH CIlzfi-O-Mg0CH wherein R is an alkyl group containing between about 18 and about 24 carbon atoms per alkyl group and having 10 a tertiary carbon atom directly attached to the nitrogen atom.

References Cited in the file of this patent UNITED STATES PATENTS 2,490,744 Trigg et a1 Dec. 6, 1949 2,604,451 Rocchini July 22, 1952 2,640,812. Bryant June 2, 1953 2,756,213 Dixon July 24, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 l2l O57 February ll 1964 Paul Y, C, Gee et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, lines 24 to 27 the lower right-hand portion of the formula should appear as shown below instead of as in the patent:

OMOCH same column 2 lines 55 to 60 the formula should appear as shown below instead of as in the patent:

column 3 line l l for "J'ahn" re ad John column 4 line "(3 for 1T5 Co form" read 175 CD to form column 7, lines 45 to 48 the formula should appear as shown below instead of as in the patent:

O u RHN C-CH CH -C -M Signed and sealed this 30th day of June 1964.

(SEAL) Attest:

ERNEST W, SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

1. A MINERAL LUBRICATING OIL CONTAINING A SMALL AMOUNT, BASED ON THE WEIGHT OF SAID OIL AND SUFFICIENT TO INHIBIT SAID OIL AGAINST RUSTING OF FERROUS METAL SURFACES, OF A METAL SALT SELECTED FROM THE GROUP CONSISTING OF (1)