US2799651A - Corrosion inhibitors and compositions containing the same - Google Patents

Description

CORROSION HBITORS AND COMPOSITIONS CONTAMING THE SAME N Drawing. Application February 20, 1953, Serial No. 338,163

16 Claims. (Cl. 252-32.7)

This invention relates to improved compositions which are effective corrosion inhibitors and which are noncorrosive to silver, silver alloys and similar metals. More particularly, the invention pertains to lubricant compositions which are non-corrosive to such metals and inhibit the corrosion thereof by sulfur and/ or corrosive sulfur-containing compounds.

Advances in the design and construction of internal combustion engines aimed at increased efliciency and economy have led to lubrication problems. To meet the increased severe demands upon engines, many types of lubricant additives have been developed to obtain certain desired characteristics. Among the more effective addition agents which have been developed for compounding with lubricants are many sulfur-containing organic compounds, such as sulfurized terpenes, sulfurized hydrocarbon oils, vegetable oils or animal oils, xanthate esters, organic polysulfide, particularly polyalkyl polysulfides, metal salts of organo-substituted thioacids of phosphorus, metal salts of the reaction product of a phosphorus sulfide and a hydrocarbon, such as for example, polybutenes and other polyolefins, and combinations of the foregoing.

Recent increased use of silver and similar metals in the construction of improved internal combustion engines has created new problems in the use of sulfur-containing additives in lubricants for such engines; the primary problem created being the corrosion of such silver parts of the engine by the sulfur-containing additives. While such corrosion can be eliminated by avoiding the use of sulfurcontaining additives in lubricants for such engines, this solution of the problem is accompanied by the loss of the highly desired beneficial effects of the additives of this type.

It is an object of the present invention to provide a non-corrosive composition. Another object of the invention is to provide a composition non-corrosive to silver and similar metals. A further object of the invention is to provide a composition which will inhibit the corrosion of silver and similar metals by sulfur and/or organic sulfur-containing compounds. A still further object of the invention is to provide a lubricant composition which is non-corrosive. Still another object of the invention is to provide a lubricant composition containing an addition agent which will inhibit the corrosion of silver and similar metals by sulfur and/ or organic sulfur-containing compounds. A further object of the invention is to provide a method of inhibiting the corrosion of silver and similar metals, Still another object of the invention is to provide a method of lubricating internal combustion engines containing silver and similar metal parts, and inhibiting the corrosion of such metals by lubricants which contain sulfur and/or organic sulfur-containing compounds.

In accordance with the present invention the foregoing objects can be attained by employing in oleaginous mate- Patented July 16, 1957 'ice in which R is a hydrocarbon radical and x is an integer at least 1 and can be as high as 9; preferably x is an integer l to about 7. The hydrocarbon radical R can be aliphatic or aromatic, including acylic, alicyclic, aralkyl, aryl, alkaryl, and alkyl radicals. The hydrocarbon radical can contain from 2 to about 30 carbon atoms, and preferably from about 8 to about 20 carbon atoms. Examples of suitable hydrocarbon radicals are ethyl, butyl, hexyl, octyl, nonyl, decyl, dodecyl, hexadecyl, octadecyl, cyclo-hexyl, phenyl, tolyl, benzyl, styryl, terpene radicals, etc.

Compounds of the above general formulation can be prepared by several methods. For example, they can be prepared by reacting 2-mercapto-4-phenyl-S-thione-1,3,4- thiadiazole with an olefinic compound, or by chlorinating the thiadiazole and subsequently reacting the chlorinated thiadiazole with a mercaptan. The thiadiazole can also be reacted with a sulfenyl halide (RSX); this reaction product per se can be used, or it may be further reacted with sulfur.

The preparation of compounds of the above general formulation is illustrated by the following examples:

EXAMPLE 1 A mixture of 22.6 parts of 2-1nercapto-4-phenyl-S- thione-1,3,4-thiadiazole and 20 parts of dipentene was stirred and heated at l00-110 C. for 2 hours. The excess dipentene was distilled in vacuum, and the bottoms filtered to give an oil-soluble brown viscous oil having a sulfur content of 29.3% and a nitrogen content of 8.32%.

EXAMPLE 2 The procedure of Example 1 was followed, substituting 16 parts alpha-methyl styrene for the dipentene. An oilsoluble dark brown viscous oil having a sulfur content of 25.2% and a nitrogen content of 7.95% was obtained.

EXAMPLE 3 The procedure of Example 1 was followed, substituting 20 parts of pinene for the dipentene. An oil-soluble viscous oil having a sulfur content of 21.3% and a nitrogen content of 6.82% was obtained.

The reaction products of the above examples have the general formula EXAMPLE 4 small amount of light yellow crystals having a melting point of 86 C.

EXAMPLE 1,3,4-thiadiazole (0.185 mole) and the reaction mixture warmed to C. 'and'stirred for4 hours. The reaction mixture waswashed with dilute alkali and water, and then stripped at 110 C. With nitrogen to remove oil-soluble clear brown liquid and 5.93% nitrogen.

The theoretical for is 30.1% sulfur and 6.5 7% nitrogen.

'EjQAh/IPLE 6 i Portions of the reaction product of Example 5 were I heated with sufficient sulfur at .1309 C. for III/2317161118 to give the following polyalkyl sulfides of 4-phenyl-'5-' I I thioh'e-l,3,4thiadiazole:'

ence'of' a catalyst, such: as sulfuric acid, phosphoric acid, boron fluoride, aluminum chloride,'or other similar halide catalysts of the Friedel-Crafts type.

The polymers employed, are preferably mono-olefin polymers or mixtures-of mono-olefin polymers and isomono-olefin polymers having molecular Weights ranging from about .150 to 50,000 or more, and preferably from carbon tetrachloride- The recovered product was an containing 28.5% sulfur thesepolymers, a hydrocarbon'mixture containing iso-' butylcne,'butylenes and butanes recovered frompetroabout 500 to about 10,000. Suchpolymerscan beobtained, for example, by the polymerization in the liquid phase of a hydrocarbon mixture containing monoand isomono-olefinnsuch as butylene; and isobutylene at a' temperature of from about -80 to about 100 P, in the presence of ametal halide catalyst, of the Friedel- Crafts type, such as for example, boron fluoride, aluminum chloride, and the like. In the preparation of leum gases, especially those gases produced in the cracking of petroleum oils in themanufacture of gasoline, can be used.

Another suitable polymer is that obtained by polymerizing inthe liquid phase, a hydrocarbon mixture,

7 comprising substantially C3 hydrocarbons in the presence (a) 2 lauryl trisulfide 4 phenyl-5-thione-'1,3,4-thiadiazole;

azole; I (c) 2 lauryl hcptasulfide-4wphenyl 5-thionc-1,3,4-thiadiazole.

' The above described reaction products can be used 'in amounts offrom about 0.02% to about 10%, and

preferably from about 0.25% to about 5%, in combination with lubricant base oils, such as hydrocarbon oils, synthetic hydrocarbon oils, such as those obtained by the polymerization of hydrocarbons, such as olefin polymers; synthetic lubricating oils of the alkylene-oxide type, for example, the Ucon oils, marketed by Carbide and Carbon Corporation, as well as other synthetic oils, such as the polycarboxylic acid ester-type oils, such as the esters of adipic acid, sebacic acid, maleic acid, azelaic acid, etc.

While the above-described reaction products can be suitably employed alone in combination with a base oil, they are usually used in combination With other lubricant addition agents, which impart various desired characteristics to the base oil. Usually, these reaction products are used in conjunction with detergent-type additives, particularly those which contain sulfur or phosphorus and sulfur addition agents. This type is usually used in amounts of from about 0.002% to about 10%, and preferably from about 0.01% to about 5%. Among the phosphorus and sulfur-containing addition agents are the neutralized reaction products of a phosphorus sulfide and a hydrocarbon, an alcohol, a ketone, an amine or an ester. Of the phosphorus sulfide reaction product additives, we prefer to employ the neutralized reaction products of a phosphorus sulfide, such as a phosphorus pentasulfide, and a hydrocarbon of the type described in U. S. 2,316,082, issued to C. M. Loan et 211., April 6, 1952. As taught .in this patent, the preferred hydrocarbon constituent of the reaction is a mono-olefin hydrocarbon polymer resulting from the polymerization of low molecular weight mono-olefin hydrocarbons, such as propylene, butenes, amylenes or copolymers thereof; Such polymers may be obtained by the polymerization of mono-olefins of less than 6 carbon atoms in the pres- .of an aluminum chloride-complex. catalyst.

The catalystis preferably prepared by heating aluminum chlo- I ride with isooctane. The hydrocarbon mixture is in troduccd into the bottom of the reactor and passed up- Ward throughthe' catalyst layer, while'a temperature of from about 50 F. toabout 110: 'F. is maintained in the reactor. The propane and other saturated gases .pass through the'catalyst, While the propylene is polymerized under these conditions. The propylene polymer can be fractionated to any desired molecular weight, Prfiferably from about-500 to about 1,000 or higher.

Other suitable polymers arethose obtained by polymerizing a hydrocarbon mixture containing about 10% to about 25% isobutylene'at a temperature of from about 0 .F. to about R, and preferably 0 'F. to about" 329.1 in, the presence of boron-fluoride. After the polymerization of the isobutylene together with a relatively minor amount of the normal olefins present, the reaction mass is neutralized, washed free of acidic substances, and the unreacted hydrocarbons subsequently separated from the polymers by distillation. The polymer mixture so obtained, depending upon the temperature of reaction, varies in consistency from a light liquid to a viscous oily material and contains polymers having molecular weights ranging from about 100 to about 2,000 or higher. The polymers so obtained may be used as such, or the polymer may be fractionated under reduced pres sure into fractions of increasing molecular Weight and suitable fractions reacted with the phosphorus sulfide to obtain the desired reaction products. The bottoms result ing from the fractionation of the polymer, which have Saybolt Universal viscosities at 210 F. ranging from about 50 seconds to about 10,000 seconds, are Well suited for this purpose.

Essentially paraiflnic hydrocarbons, such as bright stock. residuums, lubricating oil distillates, petrolatums, or paraffin Waxes, may be used. There can also be employed the condensation products of any of the foregoing hycliocarbons, usually through first halogenating the hydrocarbons and reacting with aromatic hydrocarbons in the presence of anhydrous inorganic halides, such as aluminum chloride, zinc chloride, boron fluoride, and the like.

Examples of other high molecular weight olefinic hydrocarbons which can be employed are cetcnc (C16), c'erotene (Czs), melene (C30), and mixed high molecular weight alkenes obtained by cracking petroleum oils.

Other preferred olefins suitable for the preparation of the phosphorus sulfide reaction products are olefins having at least 20 carbon atoms in the molecule of which from about 13 carbon atoms to about 18 carbon atoms, and

preferably at least carbon atoms, are in along chain. Such olefins can be obtained by the dehydrogenation of alkyl halides, preferably long chain alkyl halides, particularly halogenated parafiin waxes.

As a starting material there can be used the polymer or synthetic lubricating oil obtained by polymerizing unsaturated hydrocarbons resulting from the vapor phase cracking of paraffin waxes in the presence of aluminum chloride which is fully described in U. S. Patents 1,955,- 260; 1,970,402 and 2,091,398. Still another type of olefin polymer which may be employed is the polymer resulting from the treatment of vapor phase cracked gasoline and/ or gasoline fractions with sulfuric acid or solid adsorbents, such as Fullers earth, whereby unsaturated polymerized hydrocarbons are removed. The reaction products of the phosphorus sulfide and the polymers resulting from the voltolization of hydrocarbons as described, for example, in U. S. Patents 2,197,768 and 2,191,787, are also suitable.

Other hydrocarbons that can be reacted with a phosphorus sulfide are aromatic hydrocarbons, such as for example, benzene, naphthalene, toluene, xylene, diphenyl, and the like, or an alkylated aromatic hydrocarbon, such as for example, benzene having an alkyl substituent having at least four carbon atoms, and preferably at least eight carbon atoms, such as a long chain parafiin wax.

The phosphorus sulfide-hydrocarbon reaction product can be readily obtained by reacting a phosphorus sulfide, for example, P255 with the hydrocarbon at a temperature of from about 200 F. to about 500 F., and preferably from about 200 F. to about 400 F., using from about 1% to about 50%, and preferably from about 5% to about 25% of the phosphorus sulfide in the reaction. It is advantageous to maintain a non-oxidizing atmosphere, such as for example, an atmosphere of nitrogen above the reaction mixture. Usually, it is preferable to use an amount of the phosphorus sulfide that will completely react with the hydrocarbon so that no further purification becomes necessary; however, an excess amount of phosphorus sulfide can be used and separated from the product by filtration or by dilution with a hydrocarbon solvent, such as hexane, filtering and subsequently removing the solvent by suitable means, such as by distillation. If desired, the reaction product can be further treated with steam at an elevated temperature of from about 100 F. to about 600 F.

The phosphorus sulfide-hydrocarbon reaction product normally shows a titratable acidity which is neutralized by treatment with a basic reagent. The phosphorus sulfidehydrocarbon reaction product, when neutralized with a basic reagent containing a metal constituent, is characterized by the presence or retention of the metal constituent of the basic reagent.

The neutralized phosphorus sulfide-hydrocarbon reaction product can be obtained by treating the acidic reaction product with a suitable basic compound, such as hydroxide, carbonate, oxide or sulfide of an alkaline earth metal or an alkali metal, such as for example, potassium hydroxide, sodium hydroxide, sodium sulfide, calcium oxide, lime, barium hydroxide, barium oxide, etc. Other basic reagents can be used, such as for example, ammonia or an alkyl or aryl-substituted ammonia, such as amines. The neutralization of the phosphorus sulfide-hydrocarbon reaction product is carried out preferably in a non-oxidizing atmosphere by contacting the acidic reaction product either as such or dissolved in a suitable solvent, such as naphtha with a solution of the basic agent. As an alternative method, the reaction product can be treated with solid alkaline compounds, such as KOH, NaOH, NazCOs, KzCOs, CaO, BaO, Ba(OH)2, NazS, and the like, at an elevated temperature of from about 100 F. to about 600 F. Neutralized reaction products containing a heavy metal constituent, such as for example, fin, titanium, aluminum, chromium, cobalt, zinc, iron, and the like, can be obtained by reacting a salt of the desired heavy 6 metal with the phosphorus sulfide-hydrocarbon reaction product, which has been treated with a basic reagent, such as above-described.

Other phosphorus sulfide reaction products which can be used are the reaction products of a phosphorus sulfide and a fatty acid ester of the type described in U. S. 2,399,243; the phosphorus sulfide-degras reaction products of U. S. 2,413,332; the reaction product of an alkylated phenol with the condensation product of P285 and turpentine of U. S. 2,409,877 and U. S. 2,409,878; the reaction product of a phosphorus sulfide and stearonitrile of U. S. 2,416,807, etc.

The silver corrosion inhibiting property of the abovedescribed thiadiazole compound is demonstrated by the data in Table I, which were obtained by subjecting mixtures of hydrocarbon oil, a neutralized reaction product of P255 and a polybutene, and various herein-described 1,3,4-thiadiazole derivatives to the following test, hereinafter referred to as the modified EMD test:

A silver strip 2 cm. x 5.5 cm. with a small hole at one end for suspension is lightly abraded with No. 0 steel wool, wiped free of any adhering steel wool, Washed with carbon tetrachloride, air-dried and then weighed to 0.1 milligram. 300 cc. of the oil to be tested is placed in a 500 cc. lipless glass beaker and the oil is heated to a temperature of 300 F. (:2" F.) and the silver test strip suspended in the oil so that the strip is completely immersed therein. The oil in the beaker is stirred by means of a glass stirrer operating at 300 R. P. M. At the end of twenty-four hours, the silver strip is removed and while still hot rinsed thoroughly with carbon tetrachloride and air-dried. The appearance of the strip is then visually noted and given ratings according to the following scale:

l-Bright 2Stained 3-Grey-black 4Black, smooth 5Black, flake After the visual inspection the silver strip is immersed in a 10% potassium cyanide solution at room temperature until the silver surface assumes its original bright or silver appearance. The silver strip is then washed successively with distilled water and acetone, air-dried, and weighed.

The following lubricant compositions were subjected to the above test, and the results obtained are tabulated in Table I.

Sample A.-Contro1 (solvent-extracted SAE-30 oil+ 3.3% barium-containing neutralized reaction product of P255 and a polybutene of about 1000 molecular weight).

Sample B.A+0.75% product of Example 1.

Sample C.-A+0.75% product of Example 2.

Sample D.--A+0.75% product of Example 3.

Sample E.-A+0.75% product of Example 5.

Sample F.A+0.7S% product of Example 6(b).

Sample G.A+0.5% product of Example 6(c).

Table I Sample No.

able, the ability of 1,3,4-thiadiazole derivatives of this invention to inhibit silver corrosion is demonstrated by the above data.

The effectiveness of the herein-described 1,3,4-thiadiazole derivatives in inhibiting corrosion toward copper and/ or lead-containing metals, such as for example, copper-lead alloys, is demonstrated by the data in Table II, obtained by subjecting the above samples to the following test:

A copper-lead test specimen is lightly abraded with steel wool, Washed with naphtha, dried and weighed to the nearest milligram. The cleaned copper-lead test specimen is suspended in a steel beaker, cleaned with a hot tri-sodium phosphate solution, rinsed with water, acetone and dried, and 250 grams of the oil to be tested, together with 0.625 gram lead oxide and 50 grams of a 30-35 mesh sand charged to the beaker. The beaker is then placed in a bath or heating block and heated to a temperature of 300 F. (:2 F.) while the contents are stirred by means of a stirrer rotating at 750 R. P. M. The contents of the beaker are maintained at this temperature for twenty-four hours, after which the copperlead test specimen is removed, rinsed with naphtha, dried and weighed. The test specimen is then replaced in the beaker and an additional 0.375 gram of lead oxide added to the test oil. At the end of an additional twenty-four hours of test operation the test specimen is again removed, rinsed and dried as before, and weighed. The test specimen is again placed in the beaker together with an additional 0.250 gram of lead oxide and the test continued for another twenty-four hours (seventy-two hours total). At the conclusion of this time, the test specimen is removed from the beaker, rinsed in naphtha, dried and weighed.

The loss in weight of the test specimen is recorded after each weighing.

This test, known as the Stirring Sand Corrosion Test, is

Since weight losses 200 milligrams in 48 hours and 500 milligrams in 72 ours are allowable, the copperlead cornsion inhibiting properties of the herein-described 1,3 .4-thiadiazole derivatives are clearly demonstrated by the above data.

Under certain conditions it is desirable to use in lubricant compositions elemental sulfur or an organic sulfurcontaining compound of the type hereinabove described either alone or in combination with other additives. Effective lubricant compositions are obtained by the combination of the neutralized reaction products of a phosphorus sulfide and a hydrocarbon, as above described, with elemental sulfur, or an organic sulfur-containing compound, such as sulfurized mineral oils, sulfurized non-drying animal and vegetable oils, sulfurized olefins and olefin polymers, sulfurized sperm oil, etc., as described and claimed in U. S. Reissue 22,464, issued to C. D. Kelso et al. April 4, 1944, or with sulfurized terpenes, for example, dipentene as described and claimed in U. S. 2,422,585, issued to T. H. Rogers et al. June 17, 1947. While these compounds impart highly desired characteristics to lubricants, and effectively inhibit the corrosion of copper and/or lead, they are corrosive to silver and of h similar metals. In accordance with the present invention, however, the incorporation in such lubricant compositions of small amounts, namely, from about 0.1% to about 10%, and preferably from about 0.25% to about 5%, of the herein-described 1,3,4-thiadiazole derivatives effectively inhibits the corrosiveness of the silver corrosive compounds without impairing their other desired properties.

Although the invention has been described in connection with the use of the herein-described 1,3,4-thiadiazole derivatives in combination with the one or more secondary additives in lubricant compositions, the invention is not restricted to such use, since these derivatives find utility when used alone in various lubricant compositions or bydrocarbon oil compositions to impart improved and desired characteristics thereto. Thus, for example, these derivatives may be used alone in hydrocarbon oils of high sulfur crudes to inhibit the corrosion of such oils on silver or copper and/ or lead-containing metals.

In addition to the aforementioned detergenttype additives and corrosion inhibitors, compositions containing the herein-described derivatives of 2,5-dimercapto-l,3,4-thiadiazole can contain other additives, such as anti-oxidants, pour-point depressors, extreme pressure agents, anti-Wear agents, V. I. improvers, etc.

While this invention has been described in connection with the use of the herein-described additives and lubricant compositions, their use is not limited thereto; but the same can be used in products other than lubricating oils, such as for example, fuel oils, insulating oils, greases, nondrying animal and vegetable oils, waxes, asphalts, and any fuels for internal combustion engines, particularly where sulfur corrosion must be combatted.

Concentrates of a suitable oil base containing more than 10% of the herein-described thiadiazole derivatives alone or in combination with more than 10% of the detergenttype additive and/ or the herein-described compounds normally corrosive to silver, can be used for blending with hydrocarbon oils or other oils in the proportions desired for the particular conditions of use to give a finished product containing from 0.02% to 10% of the thiadiazole derivative alone or in combination with from 0.001% to about 10% of the detergent-type additive and/or the compound normally corrosive to silver.

Percentages given herein and in the appended claims are weight percentages unless otherwise stated.

Although the present invention has been described with reference to specific preferred embodiments thereof, the invention is not to be considered as limited thereto but includes within its scope such modifications and variations as come within the spirit of the appended claims.

We claim:

1. A lubricant composition comprising a major proportion of an oleaginous compound containing a substance normally corrosive to silver selected from the group consisting of elemental sulfur, a sulfur-containing organic compound and mixtures thereof, and from about 0.02% to about 10% of a thiadiazole having the general formula in which R is a hydrocarbon radical having from 2 to about 30 carbon atoms and x is an integer of from 1 to 9.

2. A lubricant composition comprising a major portion of a normally liquid hydrocarbon containing a substance selected from the group consisting of elemental sulfur, a sulfur-containing organic compound and mixtures thereof and from about 0.02% to about 10% of a Z-hydrocarbon sulfide-4-phenyl-5-thione-1,3,4-thiadiazole.

3. A lubricant composition comprising a major portion of a hydrocarbon lubricating oil, from about 0.001% to about 10% of a phosphorusand sulfur-containing detergent-type lubricant additive, and from about 0.02% to about 10% of a thiadiazole having the general formula in which R is a hydrocarbon radical having from 2 to about 30 carbon atoms and x is an integer of from 1 to 9.

4. A lubricant composition as described in claim 3 in which R is an aliphatic hydrocarbon radical of from about 8 to 20' carbon atoms and x is 1 to 7.

5. A lubricant composition as described in claim 3 in which the thiadiazole is 2-dodecyl disulfide-4-phenyl-5- thione-1,3,4-thiadiazole.

6. A lubricant composition as described in claim 3 in which the thiadiazole is 2-dodecyl heXasulfide-4-phenyl-5- thione-l,3,4-thiadiazole.

7. A lubricant composition as described in claim 3 in which the thiadiazole is Z-tertiary octyl disulfide-4-phenyl- S-thione-1,3,4-thiadiazole.

8. A lubricant composition as described in claim 3 in which the thiadiazole is 2-pinenyl su1fide-4-phenyl-5-thione-1,3,4-thiadiazole.

9. A lubricant composition as described in claim 3 in which the detergent-type additive is a neutralized reaction product of a phosphorus sulfide and a hydrocarbon.

10. A lubricant composition as described in claim 3 in which the detergent-type additive is an alkali metal containing neutralized reaction product of a phosphorus sulfide and an olefin polymer.

11. A lubricant composition as described in claim 3 in which the detergent-type additive is an alkaline earth metal-containing neutralized reaction product of a phosphorus sulfide and a butylene polymer.

12. A lubricant composition as described in claim 3 in which the detergent-type additive is a barium-containing neutralized action product of a phosphorus sulfide and a butylene polymer.

13. A lubricant composition comprising a major proportion of an oleaginous compound, from about 0.001% to about 10% of a compound normally corrosive to silver selected from the group consisting of elemental sulfur, 4

10 in which R is a hydrocarbon radical having from 2 to about 30 carbon atoms and x is an integer of from 1 to 9. 14. A composition as described in claim 13 in which the sulfur-containing compound is a sulfurized terpene. 15. An addition agent for corrosive sulfur-containing lubricating oils, comprising a concentrated solution of a hydrocarbon oil containing more than of a thiadiazole having the general formula L-(Sh-R in which R is a hydrocarbon radical containing from 2 to about 30 carbon atoms and x is an integer of from 1 to 9.

References Cited in the file of this patent UNITED STATES PATENTS 2,231,353 Watt Feb. 11, 1941 FOREIGN PATENTS 740,213 Germany Oct. 19, 1943 OTHER REFERENCES Chemical Abstract, vol. 14, page 1298 citing Ray, Jr., 5 Chem. Soc. (London), vol 115, pp. 1308-12 (1919).

Claims (1)

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR PROPORTION OF AN OLEAGINOUS COMPOUND CONTAINING A SUBSTANCE NORMALLY CORROSIVE TO SILVER SELECTED FROM THE GROUP CONSISTING OF ELEMENTAL SULFUR, A SULFUR-CONTAINING ORGANIC COMPOUND AND MIXTURES THEREOF, AND FROM ABOUT 0.02% TO ABOUT 10% OF A THIADIAZOLE HAVING THE GENERAL FORMULA