US3844956A

US3844956A - Lubricants containing amino and hydroxy-substituted polyphenylthioethers

Info

Publication number: US3844956A
Application number: US00326936A
Authority: US
Inventors: J Nnadi
Original assignee: Mobil Oil Corp
Current assignee: ExxonMobil Oil Corp
Priority date: 1973-01-26
Filing date: 1973-01-26
Publication date: 1974-10-29
Anticipated expiration: 1991-10-29

Abstract

Lubricants are stabilized against oxidation and have their EP and detergency properties improved by adding thereto a property improving amount of an amino-substituted polyphenylthioether.

Description

United States Patent [191 Nnadi [111 3 ,844,956 [451 Oct. 29, 1974 1 1 LUBRICANTS CONTAINING AMINO AND IlYDROXY-SUBSTITUTED POLYPHENYLTHIOETHERS [75] lnventor: John C.'Nnadi,Glassboro,N.J.'

[73] Assignee: Mobil Oil Corporation, New York,

[221 Filed: Jan. 26, 1973 211 Appl. No.: 326,936

US. Cl 252/47.5, 252/46.7, 252/47, 252/48.2, 252/48.4, 252/48.6, 252/402, 260/571 [51] Int. Cl C10m 1/42 [58] Field of Search 252/47.5, 402

[56] References Cited UNITED STATES PATENTS 2,345,239 3/1944 Cook et a1. 252/47.5 X

3,145,177 8/1964 Orloff et al. 252/52 3,156,728 11/1964 3,285,854 11/1966 3,368,975 2/1968 Davis et al. 252/565 Primary ExaminerW. Cannon.

Assistant Examiner W. Cannon Attorney, Agent, or FirmAndrew L. Gaboriault; Raymond W. Barclay; Claude E. Setliff [5 7 ABSTRACT 13 Claims, No Drawings I LUBRICANTS CONTAINING AMINO AND HYDROXY-SUBSTITUTED POLYPI-IENYLTHIOETI'IERS BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to improved lubricant compositions. More particularly, it relates to lubricants which have been improved by the addition thereto of an amino and hydroxy-substituted polyphenylthioether.

2. Discussion of the Prior Art It is well known that many organic liquids and solid used in industrial fluids, such as oils and greases, .power transmission fluids and the like, may deteriorate and lose their ability to function when subjected to oxidation. Since these substances are very often used at high temperatures, the rate of oxidative breakdown can be very rapid. This problem is particularly important in the operation of present day automotive and aircraft engines.

The breakdown of lubricant is almost always accompanied by the formation of sludge, corrosive acids and other products. These can harm the metal surfaces of engines or other machines and interfere with efficient operation of the lubricant.

The ideal way to deal with the problem of oxidation, of course, is to prevent it altogether. Since, however, most additives do not stop oxidation and the formation of potentially harmful solids, much work has also been done to find other materials that can keep the solids from settling on metal surfaces. Usually, therefore, it' is necessary to use a combination of additives where oxidation is not entirely stopped one for retarding oxidation. the other for keeping in suspension those solids resulting from the oxidation that does occur. The art does not expect to find single additives that on the one hand retard oxidation and on the other act as dispensing agents.

No art is known which discloses the compounds disclosed herein as antioxidants or dispersants in lubricants. There is patent art, however, which discloses analogous compounds as lubricants. One of these is U.S. Pat. No. 3,490,737, which teaches a combination of functional fluid and metallic compound. Another is U.S. Pat. No. 3,538,l66, disclosing a process for making an analogous thioether which may be used as a functional fluid.

SUMMARY OF THE INVENTION In accordance with the invention, there is provided a lubricant composition comprising a major proportion of a lubricant and an antioxidant or dispersant amount of a compound of the formula wherein R and R are hydrogen, hydrocarbyl of from I 6 to I00 carbon atoms, preferably alkyl having from 1 to I00 carbon atoms, preferably from about 4.to 20 carphoric acids and derivatives thereof, mercapto,

halogeno hydroxyl and cyano. For solubility in oil R, R should have greater than two carbon atoms, preferably 4 or more. X and Y are hydroxyl or amino and n is from I to l0. The X's and Ys and Rs and R s may be the same or different. The product may also be a mixture,

i.e., where it may vary. The most usual mixture will comprise compounds in which n is l, 2, or 3.

DESCRIPTION OF SPECIFIC EMBODIMENTS In general, the polyphenylthioethers may be prepared in known ways. One method, the method used herein, involves reactions that may be set forth as follows:

Q'and M are the equivalents of reactants, varied to give the desired polymeric product. For example the tetramer is obtained when Q is 4 and M is 3.

The amino group may be protected by other reactions such as acetylation or by neutralization with other mineral acids such as HBr, HF, H 50 or H PO or with organic acids such as carboxylic or sulfonic acids. The polymers may then be copolymerized with a phenol and SCI to yield polymers having X as NH: and OH. In a variation of the procedure to obtain polymers containing both the NH and OH groups, mixtures of phenol and aniline with the protectedNH- group or of partially Sch-polymerized phenol and aniline with protected NH group may be reacted. Suitable products may be obtained with partially blocked or totally unblocked arylamines as starting materials.

vent for the process. Some of these are, forexample tetrahydrofuran and paraffims.

The reaction temperature can range from 0C to 5 300C with the range between 0 and 180C preferred.

The amine hydrochloride portion of the product can be reconverted to the parent amine by washing the product with aqueous solutions of sodium or potassium hydroxides and carbonates or those of calcium. zinc. magnesium and barium. This may also be done by stirring the product with excess amounts of secondary and tertiary alkylamines.

The starting aryl compound for the polymers of this invention are those of the formula examples of which appear as follows:

The additives of this invention can be used in a wide variety of lubricant media. They can be used as effective agents in lubricating oils such as mineral oils, both naphthenic and paraffinic. including those containing substantial amounts of aromatic oils, synthetic oils, such as synthetic hydrocarbons obtained by polymerizing olefins. synthetic esters and polysiloxanes and the like. The term lubricant also includes greases made by adding a grease forming agent to any of those oils mentioned. but is not meant to include any of the thioethers themselves as lubricants. The thioethers disclosed herein are especially useful in stabilizing a lubricating oil made by reacting an aliphatic monocarboxylic acid containing from 4 to [0, preferably 5 to 9. carbon atoms with pentaerythritol. including monoand dipenterythritol or mixtures thereof. A widely used lubricating oil is made from monopentaerythritol and a mixed C -,C acid. preferably C,-, and C For purposes of illustration. the following examples are offered. It is to be remembered they are for illustration only and are not intended to limit the scope of the invention. Parts are by weight.

Example 1 NH: NH: NH:

nHzs Jz X1125 kept at I50C for 4 hours under nitrogen purge. The reaction was cooled. mixed with 500 cc of toluene and cc of tetrahydrofuran and then washed once with l00 cc 10 percent NaOH solution and twice with 250 cc of H 0. The washed product was distilled to remove the solvents and unreacted dodecylaniline. The final stage of distillation was carried out to a pot temperature of 180C and 3 mm Hg, where it was held for 2 hours. The yield of product was 509 g. it contained 2.7 percent N and 2.94 percent S and had a total base number of 8 I. This product consisted mostly of trimer, tetramer and pentamer.

Example 2 i 7 '7 NI-Is MHVNHZ Example3 ii; ET-[ ina m I S O S l CiHo L 4H0 J2 (Hr From l50 g (l mole) of p-n butylaniline, 35.5 g of HCI (1 mole) and 76.5 g of SCl (0.75 mole) reacted in 400 cc tetrahydrofuran solvent as described in Example 1. I32 g of product was obtained. It contained 5.36 percent N and 8.94 percent S, and had a molecular weight (by vapor pressure lowering) of 649, indicating the tetramer.

Example 4 Niii on on Nil:

lo s ol nHzs Collin nHiu "Has One mole (220 g) of nonyphenol was dissolved in 300 cc of tetrahydrofuran and reacted with 50 g of SCI (about 0.5 mole) at 35*50C. The reaction mixture was slowly raised to C by distilling off some tetrahydrofuran and kept at l50-l60C under nitrogen purge for 4 hours after which it was cooled to room temperature. To this product was added 300 g of dodecylaniline hydrochloride dissolved in 300 cc of tetrahydrofuran. Then 101 g SCI was added and the reaction carried out as described in Example 1. The yield of product after holding at 180C 3 mm Hg for 2 hours was 452 g. To reconvert it to the aniline, the product was dissolved in 200 cc toluene and stirred with about 1 l g of triethylamine and filtered. Finally the reaction mixture was again distilled by raising the temperature to and held it at 180C at 3 mm Hg for 2 hours. The yield of product was 476 g.

EVALUATION OF PRODUCTS The antioxidant properties of the novel compounds of this invention are measured by adding these compounds to a suitable oil and subjecting the oil to oxidation at high temperatures. The test is a bulk oil catalytic oxidation process in which a stream of dry air is passed through a heated sample of the lubricant compositions for a time at various elevated temperatures in the presence of iron, copper, aluminum and lead as catalysts. The metal samples consist of 15.6 sq. in. of sandblasted iron wire, 0.78 sq. in. of polished copper wire, 0.87 sq. in. of polished aluminum wire, and 0.167 sq. in. of polished lead surface. The antioxidant activity is evaluated as the ability of the additive to control the acid number and viscosity of the oil and'prevent them from rising at an unduly rapid rate. The sludge formation during the oxidation is estimated visually. The base stock is a mixed ester of pentaerythritol prepared by reacting an acid mixture of l mole of pelargonic acid and 3 moles of commercial valeric acid with 1 mole of technical grade pentaerythritol or a mineral oil.

The results of this test are tabulated below in separate tables.

OXIDATION TEST IN MIXED ESTER FLUID The thioethers disclosed'herein were tested as detergentsby the Sulfuric Acid Neutralization Test and the Pyruvic Acid Dispersion Test. The Sulfuric Acid Neutralization Test gives a measure of the ability of detergent additives to neutralize strong acids formed in engines operating on sulfur containing fuels. H 50 is mixed with a heated blend of the additive and the oil. A solution of this is formed in isooctane which is then centrifuged to separate insolubles.

0 The optical density of the clear solution is then measured. From this value the optical density of the original additive blend diluted to a corresponding amount with isooctane is subtracted. The difference gives the optical density of the dispersed H 50 reaction prodisooctane-oil solution is then determined. The average optical density of the oil-isooctane solution is expressed as the optical density of the dispersed H 50, reaction product. The average density of the acetone solution is expressed as the optical density of the values or either one alone is used in the evaluation of detergent additives.

The Pyruvic Acid Dispersion Test gives a measure of the dispersant value of additives and serves to predict the performance of detergent additives in engines operating on low sulfur content fuels. When used in combination with the neutralization of H 80 bench test procedures it serves to predict the performance of detergentadditives in engines operating on high sulfur content fuels. Pyruvic acid is mixed with a heated blend of the additive and the oil. The mixture is diluted with benzene' and centrifuged to separate insolubles. The insolubles aredissolvedinacetone. The optical density of the oil-benzene solution gives the total amount of color. From this value the optical density of the initial additive blend diluted with benzene to a corresponding amount is subtraced. This corrected value is expressed as the optical density of the dispersed pyruvic acid polymer. The optical density of the acetone solution is (24 hour oxitlati in) wt, expressed as the optlcal denslty of'the non dispersed lnhihiwr n- NN Sludge pyruvic acid polymer. These values are used in evalua- N .m s as N tion of the detergent additives. 450 14.25 5245 Trace The table below'summarizes the results of the tests twmvlv I run. The higher thepercentage of the test run with py- 5 I1 Ni] ruvic acid, the better the additive, while a lower value 57 N" in the sulfuric acid test indicates a-better additive. I \nlllplc 2 0.5 425 L65 25 Light 450 2.85 60 Light 1.0 425 0.76 2l Trace wt sulfuric Pyruvic 450 2.25 N1 Fwmplc .l 0.5 425 1.6 22 Li ht 50 450 2.x so Light 1.0 425 0.7 12 Trace Nflflc (L098 5 450 2.2 50 Nil Example 1 3 0.024 97.3 Iimmplc 4 0.5 425 4.05 170 Nil Example 2 3 0.137 81.9 1.0 425 -1.05 114 Nil Example 4 1 0.144 86.5

OXIDATION TEST IN MINERAL 01L* Wt. Oxidation Inhibitor I Temp.. F Time, hrs. NN KV. Sludge None 325 40 l7.() 334 Heavy 325 72 24.3 Trace Example I 2 325 72 L35 8 Nil 4 325 72 1.65 13 Light 4 325 40 L35 8 Trace Example 4 5 325 72 3.9 2| Nil sec Snlvunt refined paraffinic neutral.

acts. The optical density of an acetone extraction of the v Tests indicated that the thioethers of this invention are also useful as EP agents. The product of Example I was placed in a mixed bright and neutral mineral oil stock (62 and 38 percent by volume, respectively) having a viscosity of 481 SUS at lOF and 63 SUS at 210F. The test was run in the well known Shell Four- Ball Test at a 60 kg load at lO0F. for 30 minutes. with the following results:

Concentration Wear Scar Diameter (mm) Wt. "/1 500 rpm 1000 rpm In using the thioethers of the invention as antioxidants. dispersants or EP agents. the concentration may be selected from the range of from about 0.00] to about percent by weight, preferably from about I to about 5 percent.

I claim:

1. A lubricating oil or grease composition comprising a major proportion of said lubricating oil or grease and an antioxidant or dispersant amount of a compound of wherein R and R are hydrogen or hydrocarbyl contain- Ill ing from 1 to I00 carbon atoms, X and Y are selected from the group consisting of amino and hydroxy, such that said X and Y are never all amino or all hydroxy, and n is from zero to 10, or mixtures of such compounds.

2. The composition of claim i wherein the compound is present in the range of from about 0.001 to about 20 percent by weight.

3. The composition of claim 1 wherein the lubricant is a lubricating oil.

4. The composition of claim I wherein the lubricant comprises a grease.

5. The composition of claim 3 wherein the lubricating oil is a mineral lubricating oil.

6. The composition of claim 3 wherein the lubricating oil is a synthetic lubricating oil.

7. The composition of claim 6 wherein the synthetic lubricating oil is an ester of an aliphatic monocarboxylic acid of from 4 to l0 carbon atoms, and mixtures thereof, and pentaerythritol.

8. The composition of claim 7 wherein the acid is a mixture of pelargonic and valeric acids.

9. The composition of claim 1 wherein R and R are dodecyl, X is NH, and n is 2.

10. The composition of claim 1 wherein R and R are dodecyl, X is NH and n is zero.

11. The composition of claim 1 wherein R is dodecyl, R is nonyl, X is NH Y is OH and n is 2.

12. The composition of claim 1 wherein the hydrocarbyl is alkyl having from I to carbon atoms, aryl having from 6 to 100 carbon atoms and aralkyl having from 7 to 100 carbon atoms.

13. The composition of claim 12 wherein the alkyl contains from 4 to 20 carbon atoms.

Claims

1. A LUBRICATING OIL OR GRASE COMPOSITION COMPRISING A MAJOR PROPORTION OF SAID LUBRICATING OIL OR GRASES AND AN ANTIOXIDANT OR DISPERSANT AMOUNT OF A COMPOUND OF THE FORMULA

2. The composition of claim 1 wherein the compound is present in the range of from about 0.001 to about 20 percent by weight.

3. The composition of claim 1 wherein the lubricant is a lubricating oil.

4. The composition of claim 1 wherein the lubricant comprises a grease.

7. The composition of claim 6 wherein the synthetic lubricating oil is an ester of an aliphatic monocarboxylic acid of from 4 to 10 carbon atoms, and mixtures thereof, and pentaerythritol.

9. The composition of claim 1 wherein R and R'' are dodecyl, X is NH2 and n is 2.

10. The composition of claim 1 wherein R and R'' are dodecyl, X is NH2 and n is zero.

11. The composition of claim 1 wherein R is dodecyl, R'' is nonyl, X is NH2, Y is OH and n is 2.

12. The composition of claim 1 wherein the hydrocarbyl is alkyl having from 1 to 100 carbon atoms, aryl having from 6 to 100 carbon atoms and aralkyl having from 7 to 100 carbon atoms.