US2734869A

US2734869A - Lubricating oil additive

Info

Publication number: US2734869A
Authority: US
Publication date: 1956-02-14
Anticipated expiration: 1973-02-14

Description

LUBRICATING 01L ADDETIVE Leo V. Mullen, In, Clifton, and James M. Boyle, Bayonne,

N. 3., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application January 2, 1952, $erial No. 264,686

19 Claims. on. 252 -475 The present invention relates to lubricating oil compositions containing as an additive an oxidation inhibiting or corrosion resisting agent and to the agent itself and method for its preparation.

In the development of marketable hydrocarbon products such as lubricating oils, the trend has been to use more and more efiicient refining methods in order to improve their stability and reduce their tendency to form carbon and deposits of solid matter or sludge. While such highly refined materials possess many advantages, their resistance to oxidation, particularly under conditions of severe service, is generally decreased and they are more prone to form soluble acid oxidation products which are corrosive. They are generally less efiective than the untreated products in protecting the metal surfaces which they contact against rusting and corrosion due to oxygen and moisture. Such lubricants also often deposit thick films of varnish on hot metal surfaces, such as the pistons of internal combustion engines.

In accordance with the present invention a new class of chemical compounds has been discovered, and these compounds have been found to reduce the tendency of refined lubricating oils and otherhydrocarbon products to corrode metal surfaces when added in small quantities to such materials. These additives are active in reducing the corrosion of copper-lead and cadmium-silver bearings which are employed in internal combustion engines; they are likewise effective in inhibiting the oxidation of hydrocarbon products generally and especially those of petroleum origin; and they impart other useful properties to various products. 1

The new class of compounds forming the subject of the present invention are formed by sulfur-halogenating an unsaturated ketone containing at least one olefinic double bond with a sulfur halide. The resulting intermediate compound is then condensed with a salt of a sulfur-bearing acid whereby substantialamounts of halogen are replaced by the sulfur-bearing radical. The resulting compounds are stable and soluble in the usual hydrocarbon products such as fuels, lubricating oils and the like. They are good anti-corrosive agents for organic materials that tend to corrode the usual metals and they have other useful properties.

The ketones, which are sulfur-halogenated by sulfur halides and are then reduced in halogen content by converting to products containing sulfur bearing radicals, include those having one carbonyl group and containing at least one alkenyl, cycloalkenyl, alkenylaryl, alkenylaralkyl, alkarylalkenyl and the like hydrocarbon radicals. As heretofore mentioned, the ketone should contain at least one olefinic double bond carbon-to-carbon linkage, but the ketone may have two, three, four or even more such double bonds. It may have conjugated systems of double bonds; however, 00,13 unsaturated ketones are particularly preferred. Non-acetylenic-types ketones are also preferred. The ketones may have a total of from 4 to 30 carbon atoms; those having in a range of about 6 to 15 are most desirable. Specific unsaturated ketones useful nitecl States Patent in the practice of the present invention, which have alkylalkenyl, dialkenyl, alkylaralkenyl, cycloalkenyl-alkyl and the like radicals attached to a mono-carbonyl radical, are listed below:

6-methyl-4 hepten-3-one 2,6-methyl-2,5-heptadien-4-one 6-methyl-5-hepten-2-one 5-hexen-2-one Z-methyl-hepten- (2) -one-4 Diheptadecenyl ketone Cyclohexenylmethylketone 3,5 ,5 -trimethylcyclohexen-2-one-1 Benzalacetophenone Dibenzalacetone Benzalacetone Dicinnamylidene acetone Alkyl-alkenyl and dialkenyl radicals are generally preferred. The term alkenyl as used herein refers to an aliphatic radical having one or more olefinic double bonds.

For the preparation of the sulfur-halogenated ketones, sulfur halides selected from the group of sulfur chlorides and sulfur bromides are most suitable. Specifically, sulfur dichloride, sulfur monochloride, especially the latter, and sulfur mono-bromide are useful. In the range of about 0.2 to 2.0 mol of sulfur halide per mol of ketone may be used. Generally, in the range of at least 0.2 to 1.0 mol of sulfur halide per mol of olefinic double bond in the ketone molecule will be employed in order to introduce sufi'icient sulfur into the molecule to impart corrosion inhibition properties. The temperature which has been found most satisfactory for this reaction is in the range of about 50 to C., but higher or lower temperatures may be used. The temperature should be maintained below the decomposition temperature of the halide. The reaction may be conducted in an inert solvent such as petroleum ether, chloroform, dioxane, ether and the like at refluxing temperature.

The resulting product containing added sulfur and halogen is then reacted with a salt of a sulfur-bearing acid in order to dehalogenate at least partially the sulfur-balm genated ketone. The reaction should be carried out with sufiicient salt and under controlled reaction conditions in such a manner that a final product is obtained containing less than about 1.5 weight per cent, preferably below about 1.0 weight per cent, of halogen. Products contain ing greater amounts of halogen are generally excessively corrosive to hearing metals and the like. Conveniently, the amount of salt of the sulfur bearing acid is at least equivalent, on a. molecular basis, to the halide present in the ketone-sulfur halide reaction product. A substantially halogen-free final reaction product is then formed.

The sulfur-containing salts of'sulfur-bearing acids may be represented by the general formula GY wherein G is a sulfur-bearing radical having the following formulas:

Mercaptide i R 0-iJ-S- Xanthate S R S &-S Thioxanthate N C S R Dithiocarb amate RX\fi RX Dieeter of dithtophosphate X in the above formulas may be either oxygen or sulfur although oxygen is generally preferred. R is a hydrocarbon radical having in the range of 1 to about carbon atoms and may be alkyl, alkenyl, cyclo-alkyl, aryl, 'aralkyl and alkaryl radicals. Alkyl radicals such as methyl, ethyl, isopropyl, octyl, dodecyl, lauryl, and the like are preferred. Other hydrocarbon radicals include methyl-cyclohexyl, ethyl cyclo-hexyl, phenyl, naphthyl, benzyl, octylphenyl, and the like. Y is a cation and is preferably a metal equivalent of hydrogen. The reactive alkali and alkaline earth metals such as sodium, potassium, and calcium, etc., as well as ammonium or amine salts may be used. The sulfur-containing compounds are prepared by well-known means.

Specific salts of the above general types include potassium, sodium, lithium, barium, ammonium and the like salts of ethyl mercaptan, isoamyl mercaptan, allyl mercaptan, n-butyl xanthic acid, hexadecyl xanthic acid, ethylcyclohexyl xanthic acid, n-nonyl thioxanthic acid, benzylthioxanthic acid, isopropyl ethyl dithiocarbamic acid, didodecyl dithiocarbamic acid, diethyl dithiocarbamic acid, diphenylethyl dithiocarbamic acid, di- (methylcyclohexyl) dithiophosphoric acid, di-(Z-ethylhexyl)dithiophosphoric acid, dicetyldithiophosphoric acid, diLorol-B dithiophosphoric acid (where Lorol-B compounds are derived from Lorol-B alcohol which is a commercial mixture of higher alcohols commonly derived from coconut oil, and having from 8 to 18 carbon atoms per molecule), di(butyl mercapto) dithiophosphoric acid, and the like. Mercaptide and dithiocarbamate derivatives are particularly preferred in the present invention.

The various sulfur-bearing acid salts are not necessarily equivalent, and the type of derivative to be produced will depend largely on the concentrations used and the specific properties to be improved in various hydrocarbon products. For a given carbon content, mercaptide derivatives usually have an advantage from the standpoint of oil solubility and compatibility combined with good corrosion inhibition properties. Thiocarbamate derivatives, in addition to having good antioxidant and corrosion inhibition properties, will frequently be preferred as additives for minimizing ring sticking in motors. The dithiophosphate derivatives will sometimes be especially valuable for imparting mild extreme pressure properties to gear oils and the like. Thioxanthate and dithioester dithiophosphate derivatives will frequently be used in cutting oils where high sulfur concentrations are desired.

In carrying out the reaction, the sulfur-containing salt may be added relatively slowly to the sulfur-halogenated ketone with care being taken to prevent excessive temperature rise as a result of the exothermic reaction which takes place. The reactants may be heated together for a period of from about 0.5 to 2 hours, depending on the types of materials present. Preferably, the reaction temperatures are maintained in a range of about 50 to 150 C. Conveniently, the reaction is carried out in the presence of an inert solvent in which the halide reaction by-products are insoluble or from which such by-products may be readily removed. Such solvents include petroleum ether, methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, dioxane and the like. The heating step may be carried out under refluxing conditions when a solvent is used. The resulting metal halide will generally precipitate out of solution and may be removed by filtration, decantation or by other means. Solvent may be removed from the finished product by stripping with nitrogen or other inert gas, by distillation or by other means. A desired method for producing a relatively pure product is to filter the materials, preferably before solvent is removed, through a diatornaceous filter aid such as Hy fl If the products of the present invention are added to a mineral oil for inhibiting oxidation and preventing corrosion of metal parts and the like, they are preferably 4 used in proportions of about 0.01 to 5% or 10% by weight based on the total composition. A preferred range is from about 0.1 to 2% by weight. Concentrations up to as high as 20% or even higher may be used for extreme pressure lubricants, cutting oils, and the like or for concentrates. It is usually preferred, when marketing the additive commercially and especially when intended for use in lubricating oils, to prepare a concentrated lubricating oil solution in which the amount of additive in the composition ranges from about 20 to 50% or higher by weight, depending on the solubility of the additive in the oil. The concentrate is then conveniently transported and stored in such form and may be subsequently blended with a base lubricant in the required amount before it is used as a crank case oil or the like.

The invention will be more fully understood by reference to the following examples. It is pointed out, however, that the examples are given for the purpose of illustration only and are not to be construed as limiting the scope of the present invention in any way.

Example I Per cent Sulfur 42.43 Chlorine 3.71

(b) 24 grams (0.1 mols) of di-N-octylamine were added dropwise with stirring to 4 grams of NaOH (0.1 mol) dissolved in cc. of methyl ethyl ketone. To this reaction solution were added with external cooling 7.6 grams (0.1 mol) of CS2 dissolved in 25 grams of methyl ethyl ketone.

(c) 100 grams of the S2Cl2 treated ethyl amylene ketone (prepared in Part a) were added dropwise to the sodium di-N-octyl thiocarbamate solution (prepared in Part 12 and equivalent to 3 mols per mol of chloride in sulfurchlorinated ketone). The resulting solution was refluxed for two hours and then filtered. The MEK was distilled off, leaving a product having the final analysis:

Per cent Sulfur 29.36 Chlorine 0.92 Nitrogen 1.31

Example II Sulfur, wt. per cent 30.97 Chlorine, wt. per cent 8.79

(b) 12 grams of NaOH (0.3 mol) and 60 grams (0.3 mol) of lauryl mercaptan were added to 108 grams of the S2Cl2 treated phorone (prepared in Part a) dissolved in cc. of methyl ethyl ketone (equivalent to 1.1 mol mercaptan/mol of chloride in sulfur-chlorinated phorone). The resultant reaction mixture was refluxed for two hours with vigorous stirring and then filtered. The MEK ,5 was distilled off, leaving a analysis:

product having the final Example IIl.Lauson engine test The products prepared as described in Example I were tested in a Lauson engine, using a blend of 1% by weight of the additive in a solvent extracted naphthenic oil of SAE 30 grade. For comparison, a sample of the unblended base oil was likewise tested. The test was conducted for a period of 25 hours, the Lauson engine being operated at 1800 R. P. M. with a 1.5 indicated kilowatt load, 300 F. oil temperature and 295 F. water jacket temperature. The oils were rated on a demerit system wherein an oil giving a perfectly clean piston surface is given a rating of 0, while a rating of is given to an oil giving the worst condition which could be expected on that surface. Observations were also made on the loss in weight of the copper-lead bearing during each test. The results are shown in the following table:

Example IV.--Lab0ratory bearing corrosion test A blend was prepared containing 0.25% by weight of each of the additives prepared as described in Examples 1(c) and 2(b), using as the base oil an extracted Mid Continent paratfinic lubricating oil of SAE grade. Samples of these blends and a sample of the unblended base oil were submitted to a laboratory test designed to measure the effectiveness of the additive in inhibiting the corrosiveness of a typical mineral lubricating oil towards the surfaces of copper-lead bearings. The test was conducted as follows:

500 cc. of the oil was placed in a glass oxidation tube (13 inches long and 2% inches in diameter) fitted at the bottom with a A inch air inlet tube perforated to facilitate air distribution. The oxidation tube was then immersed in a heating bath so that the oil temperature was maintained at 325 F. during the test. Two quarter sections of automotive bearings of copper-lead alloy of known weight having a total area of sq. cm. were attached to opposite sides of a stainless steel rod which was then immersed in the test oil and rotated at 600 R. P. M. thus providing sufiicient agitation of the sample during the test. Air was then blown through the oil at the rate of 2 cu. ft. per Hour. At the end of each fourhour period the bearings were removed, washed with naphtha and weighed to determine the amount of loss by corrosion. The hearings were then repolished (to increase the severity of the test), reweighed, and then subjected to the test for additional four-hour periods in like manner. The results are given in the following table as corrosion life, which indicates the number of hours required for the hearings to lose 100 mg. in weight, determined by interpolation of the data obtained in the various periods.

Bearing Corrosion Life (Hrs.)

Oil

Unblended base oil Base oil +0.25% product of Example 1(0) Base oil +0.25% product of Example 2(b) The additives of the present invention may be used in various lubricating oil base stocks derived from petroleum distillates and residuals refined by conventional means. Hydrogenated oils or white oils may be employed as well as synthetic oils prepared by polymerization of olefins, by reaction of oxides of carbon with hydrogen, or by hydrogenation of coal. The products may also be used in the synthetic poly-ether and poly-ester-type lubricants and the like as such or blended with mineral base lubricants. The lubricants will usually range from about 35 to 150 seconds (Saybolt) viscosity at 210 F.

Other agents may of course be employed in the oil compositions, such agents including dyes, pour point depressants, sludge dispersers, thickeners, viscosity index improvers, oiliness agents, and the like. In addition to being employed in lubricants, the additives of the present invention may also be used in other mineral oil products such as motor fuels, heating oils, hydraulic fluids, cutting oils, turbine oils, transformer oils, gear lubricants, greases and other products containing mineral oils as ingredients.

What is claimed is:

l. A composition comprising a major proportion of a petroleum hydrocarbon product and a minor oxidation inhibiting quantity of product obtained by reacting a mono-carbonyl ketone containing at least one olefinic double bond, and having in the range of 4 to 30 carbon atoms, with a sulfur halide selected from the class consisting of sulfur chlorides and sulfur bromides, whereby an intermediate product containing added sulfur and halogen is formed, further reacting such intermediate product with a sulfur bearing compound of the formula GY wherein G is a radical selected from the group consisting of SR,

and

Y is a cation selected from the group consisting of alkali metals, alkaline earth metals and ammonium radicals, R is a hydrocarbon radical having in the range of l to about 20 carbon atoms, and Z is selected from the class consisting of oxygen and sulfur, by heating together at a temperature in the range of about 50 to 150 C. for a period of time sufficient to produce a final reaction product which, after separation of by-product cation halide, contains not more than about 1.5% by Weight of halogen.

2. A composition as in claim 1 in which said petroleum hydrocarbon product is a lubricating oil fraction.

3. A composition as in claim 1 in which said ketone has in the range of 6 to 15 carbon atoms and said sulfur halide is sulfur monochloride.

4. A composition as in claim 3 in which said ketone is an alkyl alkenyl ketone.

5. A composition as in claim 3 in which said ketone is a dialkenyl ketone.

6. A composition as in claim 3 in which said sulfur bearing compound is a metal dialkyl dithiocarbamate in which each alkyl radical has in the range of l to 20 carbon atoms.

7. A composition as in claim 3 in which said sulfur bearing compound is an alkyl mercaptide having in the range of l to 20 carbon atoms.

8. A composition consisting essentially of a mineral lubricating oil and the reaction product as defined in claim 1, the amount of said reaction product in the composition being in the range of about 20 to 50% by weight.

9. The process which comprises the steps of reacting a mono-carbonyl ketone containing at least one olefinic double bond and having in the range of 4 to 30 carbon atoms with a sulfur halide selected from the classes consisting of sulfur chlorides and sulfur bromides whereby an intermediate product containing added sulfur and halogen is formed, further reacting such intermediate product 'with a sulfur bearing compound of the formula GY wherein G is a radical sele'ctedfrom the group consisting of SR,

Y is a cation selected from the group consisting of alkali metals, alkaline earth metals and ammonium radicals, R is a hydrocarbonradical having in the-range of 1 to about 20 carbon atoms, and Z is selected from the class consisting of oxygen and sulfur, by heating together at a temperature in the range of about 50 to 150 C. for a period of time suificient to produce a final reaction product which, after removal of by-product cation halide, contains not more than about 1.5% by weight of halogen.

10. A process as in claim 9 wherein said ketone has in the range of '6 to 15 carbon atoms and said sulfur halide is sulfur monochloride,

11. A process as in claim 10 wherein said ketone is ethyl amylene ketone.

12. A process as in claim 10 wherein said ketone is phorone.

13. A process as in claim 10 wherein said sulfur hearing compound is a metal dialkyl dithiocarbamate in which 8 each alkyl radical has in the "range of 1 to 20 carbon atoms.

14. A process as in claim 10 wherein said sulfur bearingcom'po'und is analkyl mercaptide having in the range of 1 to 20 carbon atoms.

15. A process as in claim 9 wherein Yis a metal and the reaction is conducted in a medium in which the byproduct metal halide is insoluble.

16. As a new composition of matter, the product of claim 9.

17. As a new composition of matter, the product of claim 10.

18. As a new'composition of matter, the product of claim 13.

19. As a new composition of matter, the product of claim 14.

References Cited in the file of this patent UNITED STATES PATENTS 2,179,062 Smith et a1 Nov. 7, 1939 2,217,764 Morway et al Oct. 15, 1940 2,242,260 Prutton May 20, 1941 2,305,401 Armendt Dec. 15, 1942 2,313,611 Abramowitz et al Mar. 9, 1943 2,405,482 Zimmer et al. Aug. 6, 1946 2,451,346 McNab et al Oct. 12, 1948 2,516,119 Hersh July 25, 1950

Claims

1. A COMPOSITION COMPRISING A MAJOR PROPORTION OF A PETROLEUM HYDROCARBON PRODUCT AND A MINOR OXIDATION INHIBITING QUANTITY OF PRODUCT OBTAINED BY REACTING A MONO-CARBONYL KETONE CONTAINING AT LEAST ONE OLEFINIC DOUBLE BOND, AND HAVING IN THE RANGE OF 4 TO 30 CARBON ATOMS, WITH A SULFUR HALIDE SELECTED FROM THE CLASS CONSISTING OF SULFUR CHLORIDES AND SULFUR BROMIDES, WHEREBY AN INTERMEDIATE PRODUCT CONTAINING ADDED SULFUR AND HALOGEN IS FORMED, FURTHER REACTING SUCH INTERMEDIATE PRODUCT WITH A SULFUR BEARING COMPOUND OF THE FORMULA GY WHEREIN G IS A RADICAL SELECTED FROM THE GROUP CONSISTING OF-SR,