US3243371A - Lubricating composition - Google Patents

Description

3,243,371 LUBRKCATENG CUMPQSETHGN Glenn Fuller, Berkeley, Calif., and Bennett M. Henderson, Edwardsville, llL, assignors to Shell 9i! Company, New York, N .Y., a corporation of Delaware No Drawing. Filed Dec. 10, 1962, Ser. No. 243,629 2 Claims. (Cl. 25246.7)

This invention relates to improved lubricating oil compositions possessing muitifunctional properties. More particularly the invention relates to mineral lubricating oils useful in the lubricating of engines operating over wide temperature ranges and under corrosive, extreme pressures and other adverse conditions.

It is known that lubricating oils containing certain metallic salts or soaps such as metal sulfonates possess good dispersing and detergent properties. Such lubricants, however, tend to form metallic deposits in engine parts which interfere with the effective operation of the engine. As a result, recent trends in this field have been to the use of non-ash forming basic and essentially neutral nitrogen-containing dispersants of high molecular weight such as copolymers of polymerizable amines or amides with long-chain acrylate esters. These non-ash forming nitrogen-containing compounds are excellent detergents but under extreme pressure conditions exhibit a lack of stability and wear inhibiting properties and are non-resistant in combating sludge and corrosion. Attempts to overcome the deficiencies of these polymeric detergent materials either by modifying the polymers or using auxiliary additives has met with little success. In most cases the auxiliary additives which are promising stabilizers or wear and corrosion inhibitors are metal-containing compounds such as metal sulfonates or metal carboxylates and these are to be avoided for reasons stated.

It is an object of the present invention to provide an improved lubricating oil composition. It is another object of the invention to provide an improved detergent lubricant possessing good stability and antiwear properties. Still another object of the invention is to provide a corrosion and sludge resistant lubricating oil composition. Other objects will become apparent during the following description of the invention.

Now in accordance With the present invention, it has been found that stability sludge, wear and corrosion inhibiting properties can be imparted to lubricating oils by incorporating therein small amounts of each of Certain non-ash forming nitrogen-containing detergents selected from the group consisting of HA) an oil-soluble aminoimide of a long-chain monosubstituted polymeric hydrocarbyl succinic anhydride and (B) full or partial aminoamides or polyamine salts of long-chain monosubstituted polymeric hydrocarbyl succinic anhydride and (11) an oil-soluble bis(phosphonornethyl) disulfide having the general formula wherein the Rs are the same or different groups selected from hydrogen, hydrocarbyl groups, e.g., alkyl, aryl, aralkyl, alkaryl or cycloalkyl radicals of from 1 to 18, preferably from 1 to 6 carbon atoms, or cationic groups such as metallic or nonmetaliic cation groups, e.g., monoor poly-valent metal or amine, preferably alkylamine, and the Xs are independently chalcogen atoms having an atomic number of from 8 to 16 such as oxygen or sulfur.

In compounds of (I) by long-chain hydrocarbyl is meant an olefinic polymer straight or branch chain and derived from olefins of from 2 to 8 carbon atoms such as ethylene, propylene, l-butene, isobutene, l-hexene,

Patented Mar. 29, 1%66 styrenes and copolymers thereof, from 20 to 500 carbon atoms and a molcular weight of 300 to 5000 preferably from 800 to 1500 as determined by the light scattering method.

It is surprising to find that the bis(phosphonomethyl) disulfides when used in combination with the non-ash forming polymeric detergents of this invention impart to them properties not exhibited by these compounds when used alone, namely corrosion and wear resistant properties.

The olefinic polymer present as an oil-solubilizing substituent and detergent aid of the nitrogen-containing compounds of the present invention may be prepared by any known means provided it is Within the molecular weight range indicated above. Examples of such polymers include polyethylene, polypropylene, polybutene, polyisobutylene, copolymer of ethylene/propylene, co polymer of ethylene/isobutylene, copolymer of ethylene/ a-methylstyrene and the like. Monoalkylation of maleic anhydride with the above type olefinic polymers may also be made by conventional means known in the art, prefrably in the absence of a catalyst and at temperatures ranging from about 300 F. to 600 F., preferably between 350 F. and 450 F. The mole ratio of the polyolefin to maleic anhydride may vary from 1:1 to 1:10,

preferably from 1:1 to 1:5 respectively.

The amines used to form the compounds of 1(A) namely the succinimides, or I(l3), namely the full or partial amides or amine salts of monosubstituted polymeric hydrocarbyl succinic anhydride can be alkylene polyamines such as ethylene diamine, diethylene triarnine, triethylene tetramine, l-rnethyl ethylene diamine, l-ethyl ethylene diamine, propylene diamine, butylene diamine, trimethyl trimethylene diamine, tetramethylene diamine, diaminopentane or pentamethylene diamine, diaminohexane, hexamethylene diamine, heptamethylene diamine, diamino-octane, decamethylene diamine, and the higher homologues up to 18 carbon atoms; phenylene diamine, the alkylated phenylene diamines having nuclear substituents such as methyl, ethyl, propyl, butyl, etc., naphthalene diamine, and the alkylated napthalene diamines; N,N- dimethyl ethylene diamine, N,N-(diethylethylene)diamine, N,N-(dipropyl ethylene)diamine, N,N'-(2-hydroxypropyl)ethylene diamine, N,N-(diethylpropylene) diamine, N,N-(dipropyl propylene)diamine, N,N-(dimethyl butylene)diamine, N,N (diethyl butylene)diamine; penta-(lmethylpropylene)hexamine; tetrabutylene-pentamine; hexa (1,1 dirnethylethylene)heptamine; di-(l methyl-butylene)triamine; pentaamylenehexarnine; tri( 1,2 trimethylethylene)tetrainine; di(l methylamylene)triarnine; tetra (1,3 dimethylpropylene)pentamine; penta-(1,5-dimethylamylene)hexamine; di (l methyl-4- ethylbutylene)triamine; penta- 1 ,2-dimethyl-1 isopropylethyleneflrexarnine; tetraoctylenepentamine and the like.

The polyalkylenepolyamines can be prepared by several methods well known to the art. One well accepted method comprises reacting ammonia with an alkyl, or substituted alkyl dihalide. For example, tetraethylenepentamine has been prepared by reacting ammonia with ethylene bromide. The preferred polyamines are the ethylene amines such as ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentarnine, N-dimethyl aminopropylamine, N dimethylaminobutylamine, N diethylaminopropylamine, methylpropylaminoamylamine.

In forming the second stage of the reaction using the polyamides control of the mole ratio of the monopolyolefinic succinic anhydride and polyamine and the reaction temperature is important to obtaining desired end products of the 1(A) or I(B) type. The mole ratio of the polyarnine to the anhydride compound can vary from 0.1:1 to 1:1 respectively. The reaction temperature for formation of compounds HA), the succinimides may vary from 220 F. to 500 F., preferably from 300 F. to 450 F. and in the formation of the compounds I(B) as described above the temperature may vary from room temperature to about 300 F., preferably from 100 F. to 300 F.

The invention is illustrated by the following examples in which the percentages are by weight.

EXAMPLE I (TYPE (A) COMPOUND) 250 gms. of polyisobutylene having a molecular weight of 615 and bromine number of 21 was heated to 212 F. and 30 gms. of maleic anhydride was added slowly over a period of 30 minutes. The reactants were heated to 390 F. to 400 F. and maintained at this temperature for four'hours and then heated to 440 F. and maintained at this temperature for 16 hours. On cooling, the reactants were dissolved in 1.5 liters of petroleum spirit (6080- C. B.P.) and filtered. 19 gms. of .tetraethylene pentamine was added to the petroleum spirit solution. The petroleum spirit was distilled off and replaced by 1 liter of toluene which was also distilled off 'to azeotropically remove water, and the residue was heatwhich the absolute pressure was reduced to about 200 mm. Hg at this temperature during a period of minutes to facilitate the removal of water and excess amine. The reaction mixture was then allowed to reach room temperature at this reduced pressure. The reaction product contained 1.7% nitrogen (theory='1.8% The identity of the N-dimethylaminopropylalkenyl succinimide was established by means of infra-red spectroscopy.

EXAMPLE IV (TYPE (B) COMPOUND) Polyisobutylene succinic anhydride was prepared by reacting a polyisobutylene (M.W. 850) and succinic anhydride at around 400 F. as in Example I. About 500 gms. of polyisobutylene succinic anhydride thus formed was admixed with 50 gms. of diethylene triamine in toluene at ambient temperature. The amine was added in increments and the temperature controlled so as not to rise above about 120 F. The reaction proceeded for 15 to 30 minutes after which the solvent was removed and the end product, a semi-amine of the above reactants, had a nitrogen-content of 1.6%.

Other examples of additives of the present invention include: a

Olefin-Succinie Anhydride Amine Mole Temp., Type of End Ratio F. Product V Polyisobutylene (M.W. 850) Diethylamine 1/1 420 (A) Imido.

succinic anhydride. propylamiue. VI Polyisobutylene (M.W. 850) Tetraethylene- 1. 5/1 120 (B) Semi-amide.

succinic anhydride. pentarnine. VII Polyethylene/isobutylene Dimethylamine 1/1 450 (A) Irnide.

gig/161W. 1,000)-succinic anhypropylamine.

1 e. V VIII Polyethylene/a-methylstyrene Tetraethylene 1/1 450 (A) Imide.

, (iMaW. 800)-succinic anhypeutamine.

n e. IX Polyisobutylene (M.W. 1,000)' Tetraethylene 1/1 120 (B) Amine salts of suceinic anhydride. pentamino. polyisosuceinie anhydride.

ed to 390 F. to 400" F. and maintained at this temperature for three hours.

EXAMPLE II (INTERMEDIATE) A mixture'of 1000 gms. (1 mole) of a polybutene having a molecular weight of about 1000 and 98 gms. (1 mole) of maleic anhydride was heated at 410 F. in a nitrogen atmosphere with agitation for a period of 24 hours. The reaction mixture was cooled to 150, F. and 700 cc. of hexane added; after which the mixture was filtered under vacuum. After vacuum distillation to remove the hexane from the filtrate, the product was maintained at 350 F. at an absolute pressure of 10 mm; Hg for one hour to remove traces of maleic anhydride. The

' between 0.1% and 10% by weight, preferably between crude polybutenyl succinic anhydride thus prepared had a saponification number of 79.

EXAMPLE I1 (TYPE (A) COMPOUND) A mixture of 84 gms. (0.45 mol) of tetraethylene pentamine and 702 gms. (0.45 mol) of the polybutenyl succinic anhydride of' Example 11 hereinahove,; was

blended with agitation at 125 F. in a nitrogen atmosphere. The temperature was increased to 400 F. during a period of one hour, after which the absolute pressure was reduced to about 200 mm. Hg during a period of 30 minutes to facilitate the removal of water. The reaction mixture was then allowed to reach room tempera ture at this reduced pressure. The reaction product contained 5.1% nitrogen (theory=5.4% Infra-red analysis showed that the reaction product was an imide containing a polybutene side chain.

EXAMPLE III'(TYPE (A) COMPOUND) v i 0.25% and 5% by weight, based on the weight of the. oil.

The other essential additives are (II) bis(phosphonomethyl) sulfides represented by formula I above and preferably by disulfides having the formula: V 1

where R is hydrogen or an alkyl radical of from 1 to 8 carbon atoms or mixtures of hydrogen and C alkyl radical or the amine salt represented by 1 (A) no 0 0 OH- (A) rcrrrss onzr where A is an aliphatic amine, preferably a primary or secondary amine, such as C primary straight-chain amines, e.g., octylamine, laurylamine, stearylamine, etc., or branched-chain primary aliphatic amines, e.g., t-C alkylamine, Such as t-C H17NH2' tC12H25NH2 to ii-Q15H3LNH2, OI I'.C12H25NH2 t0 t-CL5H3LNII2, 01 C secondary aliphatic amines, such as diamylamine, di- 2 ethylhexylamine, didecylamine, etc., or the corresponding metal saltssuch as salts of alkaline earth metals, e.g., Ca, Ba, Sr, or other polyvalent metals such as Zn, Pb, Sn, Cd or Al.

The bis(phosphonomethyl) disulfides are prepared by reacting an alkali disulfide, e.g., sodium or potassium disulfide, with a halomethyl phosphono compound such as dihydrocarbyl ester of chlormethylphosphonic acid in a suitable solvent such as an aqueous alcoholic solution, at reflux temperature and under inert conditions until the reaction is completed which normally requires from 1 to 5 days. Suitable halomethylphosphonic compounds include monoor di-hydrocarbyl chloromethylphosphonates, e.g., monoor bi-butyl chloromethylphosphonate, mono or di 2 ethylhexyl chloromethylphosphonate, monoor di-lauryl chloromethylphosphonate, monoor diphenyl chloromethylphosphonate, monoor di-cyclohexyl chloromethylphosphonate, monoor di-benzyl chloromethylphosphonate, dibutyl dithiochloromethylphosphonate, diphenyl chloromethyl dithiophosphonate, dibuty'l chloromethyltrithiophosphonate and the like.

A preferred method of making the disulfides of this invention is to react sodium or potassium disulfide with an ester of chloromethylphosphonic acid in an alcoholic solution under reflux conditions and under an inert atmosphere for about 24 hours and thereafter neutralizing to a pH of about 7 an ether extract and water washing the bis(phosphonomethyl)disulfide. The product-can be used as such or treated with a strong acid such as hydrochloric acid to spring the free acid which can be converted into desired partial or full esters or polyvalent metal salts or amine salts for use as oil, fuel and grease additives as well as other uses.

The following examples illustrate the preparation of additives for use in accordance with the present invention.

EXAMPLE IA Stoichiometric amounts of sodium disulfide and dibutyl monochloromethylphosphonate were refluxed for about 24 hours in an alcoholic solution (ethanol) under nitrogen atmosphere and thereafter the pH of the mixture was adjusted to around 7 and the bis(dibutyl phosphonomethyl) disulfide was ether extracted and water washed to give a 60-65% yield of his (dibutylphosphonomethyl)' disulfide O O (C 4H0 O) z-C HzSS-O Hr; C411):

analyzed as follows:

Percent Percent Percent Percent C P S Found 45. 3 8. 5 14. 7 11. 5 Expected 45. 1 8. 43 13. 40 12. 96

EXAMPLE HA The procedure for Example I was followed except that monobuytl chloromethylphosphonate was used in the reaction and the final product was bis(monobutyl phosphonomethyl) disulfide EXAMPLE IIIA Di-Z-ethylhexylamine salt of bis(monobutylphosphonomethyl) disulfide was prepared by reacting the product of Example II with 2-ethylhexylamine in an amount sulficient to neutralize completely both acid (-OH) groups, at about 50 C. in an alcoholic solution and thereafter recovering the amine salt from the alcoholic solution.

EXAMPLE IVA r 6 disulfide, bis(diphenylphosphonomethyl) disulfide, dioc tylamine salt of bis(monobutylphosphononiethyl) disulfide, tert-octadecylamine salt of bis(monobutylphosphonomethyl) disulfide; calcium salt of bis(monobutylphosphonomethyl) disulfide and mixtures thereof.

When desired,- additional improvements with respect to oxidation stability and scuffing inhibition can be imparted to the oil compositions containing the polymer salts of this invention by incorporating small amounts (0.01%2%, preferably 0.1%-1%) of phenolic antioxidants such as alkylphenols, e.g., 2,6-ditertbutyl-4-methylphenol or p,-p(-methylene bisphenols such as 4,4-meth ylene bis(2,6-ditertbutyl phenol) or a-rylamines such as phenytl-alpha-naphthylamine; dialkyl sulfides and mixtures thereof, e.g., dibenzyl disulfide,- didodecylsulfide. Anti-scufling agents include organic phosphites, phosphates, phosphonates and their thio-derivaties, such as C -alkyl phosphites, or phosphonates, e.g., diand tributyl, octyl, lauryl, stearyl, cyclohexyl, benzyl, cresyl, phenyl phosphites or phosphates, as well as their thioderivatives, P S -terpene reaction products, e.g. P S -pine oil reaction product and alkali metal salts thereof such as a potassium salt ofa P S -ter'pene reaction product, phosphonates such as d-ibutyl methanephos-phonates dibutyl trichloromethanephosphonate, dibutyl monochloromethanephosphonate, dibutyl chlorobenzenephosphonate, and the like. The full esters of pentavale'nt phosphorus acids such as triphenyl, tricresyl, trilauryl and tristearyl ortho-phosphates or potassium salt of P 'S -te-rpene reaction product are preferred. 7

Minor amounts of each class of additives are sufiicient for a highly effective combination. The detergent polymer and the bis(phos-phonomethyl) disulfide may be' used in an amount of about (Ll-10%, preferably about 0.25- 5% by weight, while about O2%, preferably about 0.05- 1% by weight of the auxiliary additives e.g., methylene bisphenol or the organic phosphates are highly useful.

The additives of the'present invention may be used to improve various hydrocarbon lubricating oils, whether of natural origin or synthetic, especially oils which are substantially parafiinic and/or naphthenic; these may contain substantial proportions of hydrocarbons having aromatic character but the amounts and type of components should be such that the Dean and Davis (Chem. and Met. Eng., vol. 36, 19-29, pp. 618-619) viscosity index of the base oil is at least 80, preferably to 150.

The oil may be derived from a highly paraffinic crude, in which case distillation and/0r dewax-ing may be suf ficient to provide a suitable base stock; a minimum of chemical or selective solvent treatment may be used if desired. Mixed-base crudes and even highly aromatic crudes which contain parafiinic hydrocarbons also provide suitable base stocks by Well known refining tech-- niques. Usually, these comprise the separation of distillate fractions of suitable boiling range followed by selective solvent extraction with solvents such as furfural, phenol, and the like to provide raflinate fractions which are suitable for further refining by dewaxing or chemical treatment such as sulfuric acid treatment, etc. Thus, it may be a refined hydrocarbon oil obtained from a paraffinic, napht-henic, asphaltic or mixed-base crude, and/or mixtures thereof, such as SAE 5W, 10W, 20W, 20, 30, 40, 50 mineral oils. The hydrocarbon oils may be blends of different mineral oil distillates and bright stock; they may have blended therewith, in minor but compatible proportions, fixed oils, such as castor oil, lard oil and the like and/ or with synthetic lubricants, such as polymerized olefins, e.g., polyisobutylene.

The following compositions are representative of the invention:

Composition A: Percent by weight Example I additive 5.2 Example IA additive 0.3 Mineral oil (SAE 30) Balance Composition B:

Example II additive 5.0 Example IA additive 0.3 Mineral oil (10W-30) Balance Composition C:

Example 111 additive 5.0 Example IA additive 0.5 .1010 Mineral oil Balance Composition D:

Example IV additive 5.0 Example IIA additive 0.3 1010 Mineral oil Balance Composition E:

Example II additive 3.0 Example IIIA additive 0.5

' SAE Mineral oil Balance Composition F: 7

Example I additive 2.0 Example IVA additive 1.0 SAE 90 Mineral oil Balance Composition G:

Example I additive 5.2 Example IA additive 0.3 4,4'-methylene bis(2,6-ditertbutyl phenol) 0.5 SAE Mineral oil Balance Compositions of A, B and G of the present invention were tested in the Oldsmobile Scufiing Test (AMA-MS Sequence 1-tested under conditions of report section G IV of Tech. Committee B of ASTM of D-Z, October 6, 1959, as described in Report Engine Test Sequence for Evaluating Oils for API Service) and each composition gave excellent results, passing the testfour times and reducing wear by 60-80% over base oil (SAE 30 mineral lubricating oil). Compositions A, B and C also left the engine at the end of the test clean with no signs of pitting, sludge or corrosion. Similar compositons to A, B and G but in which the Example I and H additives were omitted (A', B and G) failed to pass the Oldsmobile Scufiing Test. Compositions A, B and G also passed the 480 hour L-1 Supplemental Diesel Test whereas Compositions A, B and G failed the test.

Lubricating compositions of the present invention can be used in automotive, truck, aeroplane, Caterpillar and diesel engines as well as various industrial equipment.

We claim as our invention:

1. A lubricating composition consisting essentially of a major amount of mineral lubricating oil and from about 0.1% to about 10% of each of (I) an oil-soluble succinim-ide of a mono olefinic hydrocarbyhsuccinic anhydride and a poly(C alkylene)polyamine having at least 2 amino groups in the molecule and (II) an oilsoluble bis(di-C alkyl phosphonomethyl) disulfide.

2. A lubricating oil composition consisting essentially of a major amount of mineral lubricating oil and firom about 0.1% to about 10% of each of (I) an oil-soluble succinimide of mono(polyisobutylene)suceinic anhydride and tetraethylene pentamine, the polyisobutylene radical having a molecular weight of irom 500 to 3000 and (II) oil-soluble bis(dibutylphosphonomethyl) disulfide.

References Cited by the Examiner UNITED STATES PATENTS 2,614,988 10/ 1952 Hook et al. 25246.6 2,736,706 2/1956 Morris 25246.6 2,798,045 7/1957 Buck et a1. 252-32.7 2,857,304 10/1958 Birum 260461 3,018,291 1/1962 Anderson et al. 252-515 r 3,087,936 4/1963 Le Suer 252-51.5 3,172,892 3/1965 Le Suer et al. 25251.5

FOREIGN PATENTS 515,666 8/1955 Canada. 660,918 11/ 1951 Great Britain.

DANIEL E. WYMAN, Primary Examiner.

L. G. XIARHOS, Assistant Examiner.

Claims (1)

1. A LUBRICATING COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF MINERAL LUBRICATING OIL AND FROM ABOUT 0.1% TO ABOUT 10% OF EACH OF (I) AN OIL-SOLUBLE SUCCINIMIDE OF A MONO(C20-300 OLEFINIC HYDROCARBYL) SUCCINIC ANHYDRIDE AND A POLY(C1-6 ALKYLENE) POLYAMINE HAVING AT LEAST 2 AMINO GROUPS IN THE MOLECULE AND (II) AN OILSOLUBLE BIS(DI-C1-8 ALKYL PHOSPHONOMETHYL) DISULFIDE.