US2422585A - Lubricant - Google Patents

Description

Patented June 17,1947

LUBRICANT Thomas H. Rogers, Roger W. Watson, and James W. Starrett, (3111 8 11L, assignora tostandard Oil Indiana Company, Chicago, IlL, a corporation of No Drawing. Application May a, 1944, Serial No. 534,090

This invention relates to improvements-in lubricants, particularly to lubricants containing hydrocarbon oils such as mineral oils which are non-corrosive and resistant to oxidation. More particularly the present inventionis directed to lubricants which are resistant to the formation of gums, resinous and varnish-like materials and which are non-corrosive to alloy bearings of the copper-lead type. 1

Many oils are not well suited as lubricants for use in internal combustion engines, particularly those of the type operating under severe operating conditions since under such severe operating conditions the oils are susceptible to deterioration resulting in the development of carbonaceous and/or resinous or similar varnish-like deposits in the engine and on and about the valves and rings of the engine. Furthermore, such lubricants are often corrosive, particularly to alloy bearings of the type such as copper-lead, cadmium-silver, etc., which are frequently used in such engines.

It has heretofore been discovered that certain reaction products of a phosphorus sulfide and a hydrocarbon, particularly an olefin or an olefin polymer when added to a mineral oil in small amounts in combination with small amounts of elemental sulfur or an organic sulfur compound, are effective in inhibiting the formation of varnish; sludge, carbon and the like in lubricating oils during use and in general are eflective in inhibiting corrosion to metal surfaces in contact with such oils. The use of the combination of the reaction products of a phosphorus sulfide and a hydrocarbon and an organic sulfur compound or elemental sulfur in lubricants is the subject matter of U. S. Patent 2,316,090 granted to Charles D. Kelso and Lawson W. Mixon April 6, 1943. However, it has since been found that under certain conditions, particularly in engines operating on leaded motor fuels, lubricants containing the reaction products of a phosphorus sulfid and a hydrocarbon, particularly the neu tralized reaction products, and certain organic combustion engines which do not form car- 19 Claims. (01. 252-32.?)

bonaceous deposits or resinous, varnish-like materials on and aboutv the valves, pistons and rings of such engines and which are not corrosive to metals, particularly alloy bearing metals of the copper lead type. 7 Still another object of the invention is to provide a combination of additives for lubricants which will materially inhibit the formation of carbonaceous deposits and/or res- A inous, varnish-like materials and which will renized turpentine, sulfurized pinene, sulfurized turpinol, sulfurized camphene and the lik or mixtures of terpenes. We prefer to use as starting material terpenes comprising a major part of dipentenes.

The sulfurlzed terpenes can be'prepared by sulfur-icing the desired terpene by any one of various sulfurizaticn processes. Among the sulfurization processes which can suitably be employed is that of treating the terpene with sulfur and hydrogen sulfide in the presence of water or steam at temperatures within the range of about 250 F. to 450 F. and at pressures up to about 1500 pounds per square inch for a periodof 1 to 10 hours. The sulfurized terpene can also be prepared by treating the desired terpene with a sulfur chloride, such as S201: or S012, at a temperature within the range of about F. to about 250 F. When the terpene is sulfurized with a sulfur chloride, the chlorine present in the sulfurized material can be removed by treating the sulfurized material in .a bomb .at a temperature of about 300 F. to about 400 F. with ammonia or other aqueous or alcoholic alkalies, alkali metal sulfides and polysulfides, such as a sodium sulfide, or other bases. The sulfurized terpenes which are best suited for the herein-described purpose are those which have a sulfur content of from about 5% to about 45% or more and which show slight sulfur activity, as defined below, at 210 F. with increasing activity at higher temperatures, and show a decided activity at temperatures of the order of about 300 F. or higher.

We have found that the sulfurized terpenes may be characterized by their activity toward copper at various temperatures. empirically evaluated byimmersing a polished copper strip in a mineral oil containing the sulfurized terpene and examining the strip periodically. The more desirable sulfurized terpenes show little activity toward copper at 210 F.

' when used in relatively low concentrations, e. g.

up to 2% in oil, but quickly darken a; copper strip at 300 F. when used in the same concentrations. The sulfurized terpenes containing active sulfur, as measured by rapid darkening of the copper strip at 300 F. are efi'ective corrosion inhibitors in the engine when used in concentrations as low as 0.5%. sulfurized terpenes containing less active sulfur are also efiective corrosion inhibitors in the engine but ordinarily higher concentrations are required. The sulfur activity of the sulfurized terpenes may 'be increased by heating thesulfurized material to temperatures of from about 300- F. to about 450 F. Sulfur activity of the sulfurized terpenes can also be increased by distilling the sulfurized terpene under conditions whereby the high sulfur-bearing fractions are concentrated in a 40% to about 95% bottoms. The sulfurized terpenes can also be concentrated by blowing the same with agas at temperatures of about 150 F. to about 350 F. We have found that sulfurized terpenes having a sulfur content above about 25% and preferably about 30% to about 40% or higher are most suitable when it is desired to employ low concentrations of the sulfurized terpenes in the finished lubricant.

The neutralized phosphorus sulfide-hydrocarbon reaction product can beemployed in amounts I 'within the range of from about 0.001% to about 10% and preferably from about 0.01% to about 3% and the sulfurized terpene can be employed in combination with the neutralized phosphorus sulfide-hydrocarbon reaction product in amounts of from about 0.01 to about 5% and preferably from about 0.1 to about 2%. In addition to the neutralized reaction product of the phosphorus sulfide and a hydrocarbon, the composition-may contain in addition to the sulfurized terpenes small amounts, for example from about 0.001% to about 5% of elemental sulfur or other organic sulfur compounds such as a sulfurized mineral oil or a sulfurized olefin polymer. The amount of additives in the lubricant composition as expressed herein and in the appended claims is based on a weight percentage.

As was aforesaid, one 'of the components of the improved lubricant is the neutralized reaction product of a hydrocarbon with a phosphorus sulfide such as P283, P483, P4 S7, or other phosphorus sulfides and preferably phosphorus pentasulfide, Past. The hydrocarbon constituent of this reaction is preferably a mono-olefin hydrocarbon polymer resulting from the polymerization of low molecular weight mono-olefinic hydrocarbons or isomono-olefinic hydrocarbons such as propylenes, butylenes, and amylenes or the copolymers obtained by the polymerization of hydrocarbon mixtures containing isomono-olefins and mono-olefins of less than 6; carbon atoms. Ihe polymers may be obtained by the polymerization of these oleflns or mixtures of olefins in the presence 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 monoolefin polymers or mixtures of mono-olefin polymers and isomono-olefin polymers having me- This may be lecular weights ranging from about 150 to about 50,000 or more, and preferably from about 500 to about 10,000. Such polymers-can be obtained.

for example, by the polymerization in the liquid phase of a hydrocarbon mixture containing mono-olefins and isomono-olefins such as butylene and isobutylene at a temperature of from about F. to about F. in the presence of a metal halide catalyst of the Friedel-Craftstype such as, for example, boron fluoride, aluminum chloride and the like. In the preparation of these polymers we may employ, for example, a hydrocarbon mixture containing isobutylene,

butylenes and butanes recovered from petroleum gases especially those gases produced in the cracking of petroleum oils in the manufacture of gasoline.

A suitable polymer for the reaction with phosphorus sulfide is the product obtained by poly- .merizing in the liquid phasea hydrocarbon mixture containing butylenes and isobutylenes' together with butanes and some C3 and C5 hydrocarbons at a temperature between about 0 F. and 30 F. in the presence of aluminum chloride. A suitable method for carrying out the polymerization is to introduce the aluminum chloride into the reactor and introduce the hydrocarbon mixture cooled to a temperature of about 0 F.

into the bottom of the reactor and passing it upwardly through the catalyst layer while regu lating the temperature within. the reactor so that the polymer product leaving the top of the reactor is at a temperature of about 30 F. After separating the polymer from the catalyst sludge and unreacted hydrocarbons, the polymer is fractionated to obtain a fraction of the desired viscosity such as, for example, from about 80 seconds to about 2000 seconds Saybolt Universal at 210 F.

Another suitable polymer is that obtained by polymerizing in the liquid phase a hydrocarbon mixture comprising substantially C3 hydrocarbons in the presence of an aluminum chloride complex catalyst. The catalyst is preferably prepared by heating aluminum chloride with isooctane. The temperature in the reactor is controlled within the range of about 50 F. to about F. The hydrocarbon mixture is introduced into the bottom of the reactor and passed upwardly through the catalyst layer. 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, preferably from about 500 to about 1000 or higher.

Other suitable polymers can beobtained by polymerizing a hydrocarbon mixture containing about 10% to'about 25% isobutylene at a temperature of from about 0 F. to about 100 F.

and preferably 0 F. to about 32 F. in the Dresence of boron fluoride. After the polymerization tionated under reduced pressure into fractions of increasing molecular weights, and suitablei fractions obtained reacted with the phosphorus sulfide to obtain the desired reaction products. The bottoms resulting from the fractionation of the polymer which may have Saybolt Universal viscosities at 210 F. ranging from about 50 seconds to about 10,000 seconds, are well suited for the purpose of the present invention.

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

Examples of high molecular weight oleflnic hydrocarbons which can be employed as reactants are cetene (C16) cerotene (C26) melene (C30) and mixed high molecular weight alkenes obtained by cracking petroleum oils.

Other preferred olefins suitable for the preparation of the herein-described phosphorus sulfide reaction products are olefins having at least 20 carbon atoms in the molecul of which from about 13 carbon atoms to about 18 carbon atoms, and preferably at least carbon atoms, are in a long chain. Such olefins can be obtained by the dehydrogenation of parafiins, such as by the cracking of paraffin waxes, or by the dehalogenation of alkyl halides, preferably long chain alkyl halides, particularly halogenated paraflin Waxes.

The olefins obtained by dehalogenation of long chain alkyl halides are preferably those obtained by dehalogenation of monohalogenated waxes, such as, for example, those obtained by dechlorination of monochlor paraffin wax. The alkyl halides are decomposed to yield olefins according to the reaction in which n is a. whole number, preferably 20 or more, and X is'an halogen. It is preferred to employ parafiin waxes having at least about 20 carbon atoms per molecule, and melting points upwards from about 90 F. to about 140 F.

To obtain the halogenated parafiin wax, for example, chlorinated paraffin wax, chlorin is introduced into the wax, maintained in a molten state, until the wax has a-chlorine content of from about 8% to about 15%. The chlorinated wax product is a mixture of unchlorinated wax, monochlor wax and polychlor wax. This chlorinated product may be used as such, but it is advantageous to use the substantially monochlor wax fraction. The monochlor wax fraction can be segregated from the unchlorinated wax and the polychlor wax fractions by taking advantage of the difierences in the melting points of the various fractions, since the melting point of the wax varies with the extent of chlorination, 1. e. the melting point of the unchlorinated wax is greater than that of the monochlor wax, and the melting point of the latter is greater than that of the polychlor wax. Thus, the monochlor paraffin wax can be separated from. the unchlorinated and the polychlor wax fractions by means such as sweating, fractional distillation, solvent extraction, solvent precipitation, and fractional crystallization.

-- the latter as hydrogen chloride.

corresponding olefin is obtained from the monochlor parafiin wax by removing the chlorine from The monochlor wax can be dechlorinated by heating to a temperature of from about 200 F. to about 600 F. in the presence of a dechlorinating agent such as an alkali metal'hydroxide or an alkaline earth metal hydroxide or oxide. Other alkaline inorganic or organic materials can also be used. The chlorine can also be removed from the chlorowax by heating the same for a prolonged period in the absence of any dechlorinating agent. After the dehalogenation has been completed the olefin so obtained can be further purified by removing the dehalogenating agent by means of filtration or by other suitable means.

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 parafiin waxes in the presence of aluminum chloride which is .fully described in United States Patents Nos.

1,995,260, 1,970,002, 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 absorbents such as fullers earth whereby unsaturated polymerized hydrocarbons are removed. Also contemplated within the scope of this invention is the treatment with phosphoru sulfide of the polymers resulting from the voltolization of hydrocarbons as described, for example, in United States Patents Nos. 2,197,768 and 2,191,787.

Also contemplated within the scope of the present invention are the reaction products of a phosphorus sulfide with an aromatic hydrocarbon such as, for example, benzene, naphthalene, toluene, xylene, diphenyl and the like, or with 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 parafin 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 the product by filtration or by dilution with asolvent such as hexane, filtering and subsequently The high molecular weight olefins are obtained by removing the halogen as hydrogenhalide from the halogenated paramn wax. For example, the

removing the solvent by suitable means such as by distillation. If desired the reaction product can be further treated with an agent having an active hydrogen atom such as steam at an elee vated temperature of from about 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-sulfide -hydrocarbon 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. Other metal constitua metal constituent resulting from said neutralization or resulting from the reaction of a heavy metal salt with the phosphorus sulfide-hydrocarbon reaction product treated with a basic reagent.

The neutralized phosphorus sulfide-hydrocarbon reaction product can be obtained by treating the reaction product with a suitable basic compound such a a hydroxide, carbonate or an oxide of an alkaline earth metal or an alkali metal such as, for example, potassium hydroxide or sodium hydroxide. Other basic reagents can be used such as, for example, ammonia or an alkyl or aryl substitute of 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 reaction product either as such or dissolvedin a suitable solvent such as naphtha with a solution of the basic reagent, for example, potassium hydroxide or sodium hydroxide dissolved in alcohol. As an alternative method, the reaction product can be treated with solid alkaline compounds such as KOH, NaOH, NazCOz, K2003, CaO, and the like at an elevated temperature of from about 100 F. to about 600 F. As was aforesaid, when the phosphorus sulfide-hydrocarbon reaction product is neutralized with a basic reagent containing a metal constituent, the neutralized reaction product is characterized by the presence of the metal constituent of the basic reagent. Neutralized reaction products containing a heavy metal constituent such as, for example, tin, titanium, aluminum, chromium, cobalt, zinc, iron, and the like, can be obtained by reacting a salt of 'the desired heavy metal with the phosphorus sulfide-hydrocarbon reaction product which has been treated with a basic reagent. It will be understood that when the neutralization is accom- As noted above it has been disclosed hereto covered that superior and much more effective corrosion inhibition is obtained when a sulfurized terpene, instead of the sulfur-containing organic compounds heretofore described, is used in combination with the phosphorus sulfide-hydrocarbon reaction product and particularly the neutralized phosphorus sulfide-hydrocarbon reaction product. v

The, improvement obtained when a small amountofwsulfurized-terpene is used in combination with a neutralized phosphorus sulfidehydrocarbon reaction product is illustrated by the data presented in the following table. The data presented therein are those obtained in the socalled 36 Hour Chevrolet Test made in accordance with the Cooperative Research Council test procedure C. R. C. Designation L-4-243" of February, 1943. This test is made in a six cylinder spark-ignition internal combustion engine equipped with two copper-lead alloy bearings and operating at about 3150 R. P. M. with anoil temperature of 280 F. 2 F. The copper-lead alloy bearings are weighed before the test and at the end of the test period and the amount of corrosion expressed in grams per full bearing loss during the operating period. The following oils were tested by this method:

A. 'A solvent refined M. Ca 's. A E. 30 motor oil.

B. A solvent refined M. C. S. A. E. 30 motor oil containing a sumcient amount of a neutralized phosphorus pentasulfide-isobutylene polymer reaction product to give 0.042% phosphorus in th final blend.

C. B+.25% sulfurized mineral oil.

D. C+1.5% of a sulfurized isobutylene tetramer equivalent to0.09% sulfur in the final blend.

E. C+0.5% dixylyl disulflde equivalent to 0.12% sulfur in the final blend.

F. C+0.25% ethyl xanthate disulfide equivalent to 0.13% sulfur in the final blend.

G. C+0.25% sulfurized terpene equivalent to 0.07% sulfur in the final blend.

H. C+0.5% sulfurized terpene equivalent to 0.15% sulfur in the final blend.

I. B+0.5% sulfurized terpene equivalent to 0.15% sulfur in the final blend.

Table I Copper-Lead Alloy Bearing Duration Corrosion of Test The above data demonstrate the .marked corrosion inhibition effect of sulfurized terpenes (oil samples G and I) compared with other sulfurcontaining organic compounds. Numerous tests have shown that the presence of small'amounts of sulfurized mineral oil in oil compositions such as exemplified by Examples D to I inclusive has a substantially noeffect on the other sulfur materials in the composition; this is demonstrated by the data obtained on .oil sample'I.

The corrosion inhibiting efi'ect of sulfurized terpenes and the superiority of such compounds over other sulfur-containing organic compounds is further demonstrated by the data in Table II.

I The data in Table II were obtained in the so-- called 500 hour test" made in accordance with the Cooperative Research Council test procedure "C. R. C. Designation 1,-5-243 of February, 1943. This testis made in a compression-ignition internal combustion engine equipped with copperlead alloy bearings and operating at an engine speed of 2000 R. P. M. with an oil temperature of 230F.i2F. In this test the copper-lead alloy in the final blend+.2% sulfurized sperm oil equivv alent to .20% sulfur.

Table-r1 Oil Sample Bearing Corrosion Results A Copper-lead alloy bearings averaged under 0.1 gram loss per full hearing at the end of the 500 hour test. B Bearings so badly corroded at the end of 48 hours the test had to be stopped to prevent serious mechanical damage to such engine parts as shaft and connecting rods. New bearings inserted and test continued. In 210 hours additional running period the hearings were again so badly corroded the test was stopped.

The results obtained in the above tests again clearly show the superiority of sulfurized terpenes over other sulfur-containing organic compounds.

Although the present invention has been described as applied to hydrocarbon lubricating oils, the invention is not limited thereto but contemplates the use of sulfurized terpenes in combination with the reaction products of a phosphorus sulfide and a hydrocarbon, particularly the neutralized reaction products thereof, in products other than hydrocarbon lubricating oils such as, for example, fuel oil, insulating oils, turbine oils, non-drying vegetable and animal oils, synthetic oils, greases and the like. I

While the invention has been described by reference to various representative constituents and has been illustrated by reference to specific examples thereof, the invention is not to be limited to the various representative compounds named or to the specific examples given but includes within its scope such modifications as come within the spirit of the appended claims.

We claim:

1. An oleaginous composition comprising a major proportion of a hydrocarbon oil and in combination therewith from about 0.01% to about 5% by weight of a sulfurized terpene and from about 0.001% to about by weight of the neutralized reaction product of a phosphorus sulfide and a hydrocarbon.

2. A lubricant composition comprising a major proportion of a hydrocarbon oil and in combination therewith from about 0.01% to about 5% by weight of a sulfurized terpene and from about 0.001% to about 10% by weight of the neutralized reaction product of a phosphorus sulfide and a hydrocarbon.

3. A lubricant composition comprising a major proportion of a hydrocarbon oil and in combination therewith from about 0.01% to about 5% by weight of a sulfurized terpene and from about 0.001% to about 10% by weight of the neutralized reactionproduct of a phosphorus sulfide and an olefin.

e. A lubricant composition as described in claim 3 in which the olefin is anolefin containing at least carbon atoms in the molecule of 10 which from about 12 carbon atoms to, about 18 carbon atoms are in a. long chain.

5. A lubricant composition comprising a major proportion of a. hydrocarbon oil and in combination therewith from about 0.01% to about 5% by weight of a. sulfurized terpene and from about 0.001% to about 10% by weight of the neutralized reaction product of a. phosphorus sulfide and an olefin polymer.

6. A lubricant composition as described in claim 5 in which the olefin polymer is an isobutylv ene polymer.

7. A lubricant composition as described in claim 5 in which the olefin polymer is a propylene polymer.

8. A lubricant composition comprising a major proportion of a hydrocarbon-oil and in combination therewith from about 0.01% to about 5% by weight of a sulfurized terpene, and from about 0.001% to about 10% by. weight of the neutralized. reaction product of a phosphorussulfide and an olefin polymer, said neutralized reaction product containing a metal constituent.

9. A lubricant composition as described in claim 8 in which the metal constituent is an alkali metal.

10. A lubricant composition as described inclaim 8 in which the metalconstituent of the neutralized reaction product is potassium. 1

11. A lubricant composition as described in claim 8 in which the metal constituent of the neutralized reaction product is sodium.

12. A lubricant composition as described in claim 8 in which the metal constituent of the neu- 13. A lubricant composition as described in claim a in which the metal constituent of the neuterpene and from about 0.001% to about 10% by weight of the neutralized reaction product of a phosphorus pentasulfide and an olefin polymer.

.16. A lubricant composition comprising a major proportion of a hydrocarbon oil and in combination therewith from about 0.001% to about 10% by weight of a metal-containing neutralized reaction product of a phosphorus sulfide and a hydrocarbon and from about 0.01% to about 5% by weight of a sulfurized terpene exhibiting high sulfur activity at temperatures of about 300 F. and higher.

17. A lubricant composition comprising a' major proportion of a hydrocarbon oil and in combination therewith from about 0.001% to about I 10% by weight of a metal-containing neutralized reaction product of a phosphorus sulfide and a hydrocarbon and from about 0.01% to about 5% by weight of a sulfurized terpene subjected to heat treatment to impart thereto high sulfur activity at temperatures of about 300 F. and

REFERENCES crmn The following references are of record in the file of this patent:

' Number UNITED STATES PATENTS Name Date Kelso Apr. 6, 1943 Zimmer Jan. 5, 1943 Zimmer June 17, 1941 Kaufman June 9, 1936 Kaufman June 9, 1936 Palmer Sept. 12, 1933 Kobbe Feb. 9, 1932