US3238131A - Lubricating compositions containing bis(phosphono-methyl) disulfides - Google Patents

Description

3,238,131 LUBRICATING COMPOSITIQNS CUNTAINING BIS(PHGSPHON-METHYL) DISULFIDES George M. Calhoun and Hyman Diamond, Berkeley, Calif., assignors to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 23, 196i), Ser. No. 77,817 4 Claims. (Cl. 252-6237) This invention relates to improved functional organic compositions and additives therefor. More particularly, the invention relates to fuel and lubricant compositions having improved stability and extreme pressure properties and additives therefor.

In general, hydrocarbon compositions are doped with various oil-soluble compounds, namely, stabilizers and antioxidants, such as phenolic compounds, e.g., alkyl phenols and bisphenols; detergent and corrosion inhibitors which may be organic salts such as carboxylates, phenates, phosphates, sulfonates and thio-carbamates; antiwear and extreme pressure compounds such as esters of fatty acids and polyhydric alcohols or alkyl or aryl phosphites or phosphates, or free fatty acids and sulfur derivatives thereof such as C1048 fatty acids (oleic or stearic acids) and sulfurized unsaturated fatty acids, e.g., sulfurized oleic acid. However, these compounds when used in liquid hydrocarbons, such as lubricating oil compositions which are subjected to high temperatures and pressures, break downiand fail to impart their expected desired properties under these extreme conditions.

It has now been discovered that liquid hydrocarbon compositions are improved with respect to stability, wear inhibition and extreme pressure properties, and contribute to minimizing octane requirement increase when used in an internal combustion engine, and the like by incorporation therein of a minor amount of an oil-soluble bis- (phosphonomethyl) 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 non-metallic 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. Preferred compounds of the general formula (I) have the following formula:

0 o (R10)z-CHz-SSCHg-(OR1); (II) where R is hydrogen or an alkyl radical of from 1 to 8 carbon atoms or mixtures of hydrogen and an C alkyl radical or the amine salt represented by Patented Mar. 1, 1966 where A is an aliphatic amine, preferably a primary or secondary amine, such as C primary straight-chain amines, e.g., octylam'ine, laurylamine, stearylamine, etc., or branched-chain primary aliphatic amines, e.g., t-C alkylam-ine, such as t-C H NH t-C H NH to t-C H NH or C secondary aliphatic amines, such as diamylamine, di-Z-ethylhexylamine, didecylamine, etc., or the corresponding metal salts such 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(methylphosphono) disulfides are prepared by reacting an alkali disulfide, e.g., sodium or potassium disulfide, with a halomethyl phosphono compound such as dihydrocarbyl ester of chloromethylphosphonic 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 about 5 days. Suitable halomethylphosphonic compounds include monoor di-hydrocarbyl chloromethylphosphonates, e.g., mono-or di-butyl chloromethylphosphonate, monoor di-Z-ethylhexyl chloromethylphosphonate, monoor di-lauryl chloromethylphosphonate, monoor di-phenyl chl'oromethylphosphonate, monoor di-cyclohexyl chloromethylphosphonate, monoor dibenzyl chloromethylphosphonate, dibutyl dithiochloromethylphosphonate, diphenyl chloromethyl dithiophosphonate, dibutyl chloromethyltrithiophosphonate and the like.

A preferred method of making the disulfides of this invention is to react sodium or potassium disulficle 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 and 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 Percent Percent Percent Percent O P S Found 45. 3 8. 5 14. 7 11. 5 Expected 45. 1 8. 43 13. 40 12. 96

Example 11 The procedure for Example I was followed except that monobutyl chloromethylphosphonate was used in the reaction and the final product was bis(monobutyl phosphonomethyl)disulfide Di-Z-ethylhexylamine salt of bis(mono-butylphosphonomethyl)disulfide was prepared by reacting the product of Example 11 with Z-ethylhexylamine in an amount sufficient 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 IV Following the procedure of Example III, the tertoctadecylamine salt of the product of Example II was prepared using tert-octadecylamine, available commercially under the trade name of Primene JM-T, instead of di-Z-ethylhexylamine.

The following additional bis(phosphonomethyl)disulfides illustrate the additive of the present invention: bis- (phosphonomethyl)disulfide, bis(monooctyl phosphonomethyl)disulfide, bis(dicyclohexyl phosphonomethyl)disulfide, bis(dibenzyl phosphonomethyDdisulfide, bis(diphenyl phosphonomethyl)disulfide, dioctylamine salt of bis(monobutyl phosphonomethyl)disulfide, tert-octadecylamine salt of bis(monobutyl phosphonomethyl)disulfide, calcium salt of bis(monobutyl phosphonomethyl)disulfide and mixtures thereof.

Additional improvement of oil and fuel compositions containing the above addition of the present invention, namely the bis(phosphonomethyl)disulfide, particularly with respect to oxidation and storage stability, is accomplished by addition of small amounts of alkylated bisphenols having the general formula:

and preferably having the formula:

wherein in (V) X stands for S-, --S-S-, Se, S-CH CH SCH CHR, -CR -(CH pNH--, -O, and R stands for methyl or ethyl, n stands for an integer from 1 to 3; in (VI), X is CH or sulfur and R is a tertiary alkyl radical. The most preferred alkylated bisphenols are represented by Formula VI, those having a sulfur bridge or, and most especially, a methylene bridge and where R is a tertiary butyl radical.

The alkylated bisphenols may contain from 1 to 8 alkyl groups, but preferably they contain from 2 to 6 alkyl groups; alkylated bisphenols having 4 alkyl groups are particularly preferred. Each of the alkyl groups may contain from 1 to carbon atoms, preferably 2 to 6 carbon atoms, and especially 4 carbon atoms. Furthermore, the alkyl groups in any particular bisphenol may be the same or different and may also be primary, sec ondary or tertiary alkyl groups. Bisphenols containing at least one tertiary alkyl group are particularly preferred.

The alkylated bisphenol may be prepared by any of the methods known in the art of bisphenol manufacture, for example, by selecting the appropriate alkylated phenols as starting materials and condensing them together by any of the established methods. For example, alkylated bisphenols may be prepared by the method described in U.S. Patent 2,944,086.

As examples of the alkylated bisphenols which may be used according to the invention, there are mentioned his 3 -ethyl-4-hydroxyphenyl) disulfide,

bis 3-methyl-4-propyl-S-hydroxyphenyl) disulfide,

bis 2-isopropyl-3 -butyl-5-hydroxyphenyl selenide,

2,2diethyl-3-tertiary-butyl4,4'-dihydroxydiphenyl selenide,

bis 1,2 2,6-di-tertiary-butyl-4-hydroxyphenyl thiaethane,

bis 1,2 (2,5-diisopropyl-3-hydroxyphenyl) thiaethane,

bis(3,5-di-tertiary-butyl-4-hydroxyphenyl) -sulfide,

2,4-diisobutyl-3-hydroXybenZyl-2',4'-dipropyl-3 -hydroxybenzyl sulfide,

bis 1,2 3-octy1-5-tertiary-butyl-4-hydroxyphenyl) ethane,

bis 1, 1 (2,6-diisopropyl-4-hydroxyphenyl ethane,

1,2-bis (2,4-di-tertiary pentyl-3-hydroxyphenyl) propane,

bis 2,2 4,5 -di-tertiary-butyl-2-hydroxyphenyl propane,

bis Z-tertiary-butyl-5-isopentyl-4-hydroxyphenyl) amine,

bis( 3 ,5 -dibutyl-5 -hydroxypl1enyl) ether,

bis 2,6-dipropyl-4-hydroxyphenyl ether.

Preferred compounds are the alkylated bisphenols having a sulfur or methylene bridge, the former including bis(2,5-dipentyl-4-hydroxyphenyl)sulfide, bis(2,5-dihexyl- 3-hydroxyphenyl) sulfide, bis(Z-methyl-S-tertiary butyl-4- hydroxyphenyl)sulfide, bis(Z-methyl S tertiary-butyl-6- hydroxyphenyl)sulfide and, particularly, bis(3-tertiarybutyl-S-methyl-Z-hydroxyphenyl)sulfide, and examples of the latter, namely, alkylated bisphenols having a methylene bridge, include bis(2,3 ditertiary-butyl 4 hydroxyphenyl)methane, bis(2,5-di tertiary butyl 4 hydroxyphenyl)methane, bis( 2,6 di tertiary butyl 4-hydroxyphenyl)methane, bis(3,5 di tertiary octyl 4 hydroxyphenyl)methane, bis(3-tertiary-butyl 5 tertiary-octyl-4- hydroxyphenyl)methane, and, especially, bis(3,5-di-tertiary-butyl-4-hydroxyphenyl) methane.

Also the phosphonomethyldisulfide additive, alone or in combination with a bisphenol, appears to co-act with certain phosphorus compounds to give additional unexpected improvement in anti-wear and anti-scuffing. Thus, this desirable improvement can be imparted to lubricants of this invention by also incorporating a small amount (0.01-2%, preferably 0.1-1%), of a partial or full ester of an organic phosphorus compound. Phosphorus compounds of this type include alkyl, cycloalkyl, alkaryl, aralkyl, and aryl phosphites, phosphates, phosphonates, and their thio derivatives, such as C alkyl phosphites, e.g., diand tri-butyl, octyl, lauryl, stearyl, cyclohexyl, benzyl, cresyl, phenyl phosphite or phosphates, as Well as their thio derivatives; P S -pine oilreaction product, and metal salts thereof such as Na, K, Ca or Ba salts of P S -terpene reaction product; dibutyl methylphosphonate, dibutyl trichloromethylphosphonate, dibutyl monochloromethylphosphonate, dibutylchlorophenylphosphonate, dibutyl monochloromethylphosphonate, dibutyl chlorophenylphosphonate, and the like. The esters of pentavalent phosphorus acids such as diphenyl, dicresyl, triphenyl, tricresyl, trilauryl and tristearyl orthophosphates, P 5 terpene reaction products and mixtures thereof are preferred.

Minor amounts of each class of additives are sufficient for a highly effective combination. The bis(phosphonomethyl) disulfide may be used in an amount of about 0.1-10%, preferably about 0.25% by weight, while about ODS-2%, preferably about 0.11%, of the methylene bisphenol or sulfide derivative thereof is highly useful and about 0.1%2% of an organic phosphorus compound as described in the preceding paragraph.

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 paratiinic and/or naphthenic; these may contain substantial proportions of hydrocarbons having aromatic character but the amounts and types of components should be such that the Dean and Davis (Chem. and Met. Eng, vol. 36, 1929, pp. 618-619) viscosity index of the base oil is at least 80, preferably to 150.

The oil may be derived from a highly paratfinic crude, in which case distillation and/ or dewaxing may be sufficient 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 paraffinic hydrocarbons also provide suitable base stocks by well known refining techniques. Usually, these comprise the separation of distillate fractions of suitable boiling range followed by selec tive solvent extraction with solvents such as furfural, phenol, and the like to provide ratfinate 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, naphthenic, asphaltic or mixed-base crude, and/or mixtures thereof, such as SAE 5W, W, W, 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 Example I additive 2 1010 mineral oil Balance Composition B:

Example II additive 2 1010 mineral oil Balance Composition C:

Example III additive 2 1010 mineral oil Balance Composition D:

Example IV additive 2 1010 mineral oil Balance Composition E:

Example II additive l SAE mineral oil Balance Composition F:

Example I additive 2 SAE 90 mineral oil Balance Composition G:

Example I additive 2 Bis(3,5 di tert butyl 4 hydroxyphenyl)- methane .5 SAE 90 mineral oil Balance Composition H:

Example I additive 5 Ucon HB660 (polyethylene-propylene glycol having a SUS viscosity at 100 F. of 660) Balance Composition 1:

Example I additive Q 2 Di-2-ethylhexyl sebacate Balance Composition J:

Example I additive 1 Leaded gasoline (3 cc. of TEL) Balance Composition K:

Example I additive 0.1

Fuel oil (No. 2) Balance Speed, r.p.m. 3200 Oil temperature, C 100 Oil flow-rate, cc./sec. 10 Load in increments, 5 min. at each setting.

Results of the evaluations are given in Table I and, for the purpose of comparison, the results obtained from theuse of the base oil alone and with other known extreme pressure compositions are also given.

TABLE I Composition: Score load, lbs./ in. A through I 6,400 1010 mineral oil+2% C alkenyl succinic acid 1,400 1010 mineral oil+2% malonic acid 2,800 1010 mineral oil+2% 3-hexadecyl adipic acid 1,400 1010 mineral oil+2% dodecylmerca-ptosuccinic acid 1,400 1010 mineral oil+10% glycerol monooleate 1,800 1010 mineral oil-|-2% C13H27OH (Oxo" process) 600 1.010 mineral oil 600 The following compositions were also tested for stability in the Dornte Oxidation Test described in the Natural Petroleum News, September 17, 1941, pages 294-6, under the following conditions: 302 F., iron catalyst, mineral white oil base; additive amount by weight in Other representative compositions of this invention which are similarly elfective are:

(5) Mineral oil+0.15% 1,l-bis(3,5-di-tert-butyl-4-hydroxyphenyl) methane+0.15 Example I additive.

(6) Mineral oil+0.5% 1,1 bis(3,5 di tert butyl 4- hydroxyphenyl)methane-P05% Example II additive. (7) Fuel oil+0.15% 1,1 bis(3,5 di tert butyl 4- hydroxyphenyl)ethane+0.15 2,6 di tert butyl 4- methylol+0.3% Example I additive.

(8) Gasoline+0.05% 1,1- bis(3 isopropyl 5 tert butyl-4-hydroxyphenyl)methane+0.05% Example III additive.

(9) Di-Z-ethylhexyl sebacate+0.15% 1,l -bis(3-met-hyl-5- tert-butyl-4-hydroxyphenyl methane 0.15 Example IV additive.

Compositions of this invention are particularly applicable for high-temperature high-speed use as in aviation engines, automotive engines and truck engines, as well as industrial equipment operating under the conditions described in this invention.

We claim as our invention:

1. A mineral oil composition comprising a major amount of mineral oil and from about 0.1% to about 10% of an oil-soluble bis (phosphonomethyl) disulfide having the general formula x X (RX);-PCH2SSCH2;(XR);|

where the Rs are radicals selected independently from the group consisting of hydrogen, C alkyl radical, and C alkylamine and X is a chalcogen having an atomic number of from 8 to 16.

2. A mineral lubricating oil composition comprising a major amount of mineral lubricating oil and from about 0.2% to about 5% of an oil-soluble bis(di-C -alkyl phosphonomethyl) disulfide.

3. A mineral lubricating oil composition comprising a major amount of mineral lubricating oil and from about 0.2% to about 5% of bis(dibutyl phosphonomet-hyDdisulfide.

4. The composition of claim 3 containing from about 0.05% to about 2% of 1,1-bis(3,S-di-tert-butyl-4-hydroxyphenyl) methane.

References Cited by the Examiner UNITED STATES PATENTS 2,614,988 10/1952 Hook et al 25246.6 2,725,359 11/1955 Harman et al 260461 Morris 25246.6 Buck et a1 25232.7 Filbey et al.

McDermott 25246.6

Birum 260461 Birum 260-461 Hoffman 260461 Neff 25246.6

FOREIGN PATENTS Canada. Great Britain.

DANIEL E. WYMAN, Primary Examiner. 15 JULIUS GREENWALD, Examiner.

Claims (2)

1. 3. A MINERAL LUBRICATING OIL COMPOSITION COMRISING A MAJOR AMOUNT OF MINERAL LUBRICATING OIL AND FROM ABOUT 0.2% TRO ABOUT 5% OF BIS(DIBUTYL PHOSPHONOMETHYL)DISULFIDE.
2. 4. THE COMPOSITION OF CLAIM 3 CONTAINING FROM ABOUT 0.05% TO ABOUT 2% OF 1,1-BIS(3,5-DI-TERT-BUTYL-4-HYDROXYPHENYL)METHANE.