US3093584A

US3093584A - Zinc salts of p2s5-olefin-chloral reaction products as extreme pressure agents

Info

Publication number: US3093584A
Application number: US47945A
Authority: US
Inventors: Richard L Ferm
Original assignee: California Research LLC
Current assignee: California Research LLC
Priority date: 1960-08-08
Filing date: 1960-08-08
Publication date: 1963-06-11
Anticipated expiration: 1980-06-11

Description

United States Patent r 3,093,584 ZINC SALTS OF P S -0LEFlW-CHL9RAL REACTION PRODUCTS AS EXTREME PRESSURE AGENTS Richard L. Ferm, El Cerrito, Califi, assignor to California Research Corporation, San Francisco, Cnlif.,a curporation of Delaware No Drawing. Filed Aug. 8, 1960, Ser. No. 47,945 7 Claims. (Cl. 25232.7)

This invention relates to lubricating oil compositions containing oil-soluble agents which are effective in imparting extreme pressure characteristics to the lubricating oil compositions.

It is well known that the normal lubricating oil compositions used for the lubrication of various parts of internal combustion engines, automobile chassis, and machinery in general are likely to fail when unusually heavy pressures are applied thereto.

in the automotive field, in order that automobiles may be built with less height, it has been necessary to provide smaller gears throughout the automobile assembly. Although these gears are smaller, the power requirements from the engines themselves have continued to increase. As a consequence, the smaller bearing and gears carry larger loads per unit area than was heretofore necessary with the larger bearings. Pressures in the order of hundreds of thousands of pounds per square inch are exerted in the hypoid gear assemblies so commonly used in automotive vehicles. If such pressures result in the squeezing out, as it were, of all of the oil between the contacting metal surfaces, thesemetal surfaces will contact each other directly, resulting in the formation. of extremely high temperatures due to friction, terminating with seizure or excesive wear and early failure of the metal wearing parts.

It is known from the prior art, for example, that zinc alkyl dithiophcsphates derived from P 8 and alcohols are useful in lubricant compositions as extreme pressure agents. However, lubricants having extreme pressure characteristics mount to be characterized only as such,

' but in addition, such lubricants should have high lubricating film strength, impart low rates of Wear and low coefficients of friction. However, the new extreme pressure additives described herein are considerably superior to the prior art additives in these respects.

It is a primary object of this invention to set forth lubricating oil compositions having extreme pressure characteristics that do not suffer loss or deterioration of high film strength, low rates of wear, or low coefiicients of friction in long continued use under severe conditions.

Therefore, in accordance with this invention, it has been discovered that lubricating oil compositions having high extreme pressure characteristics are obtained by incorporating therein the zinc salt of the product obtained by reacting (a) a phosphorus sulfide with an olefin (b) reactingthe product obtained from (a) with chloral, (c) reacting the product'obt'ained from (b) with Zinc oxide or hydroxide).

The lubricating oil compositions described herein not only have high extreme pressure characteristics, but they also have excellent oxidation stability;

The phosphorus sulfide used herein as a reactant is preferably phosphorus pentasulfide (i.e., P 8

The olefins are polymers of propylene and butylene,

c CC

which polymers have molecular weights in the range of about l75 to about 500. That is, the olefins used herein in reaction with the phosphorus sulfides are polypropylenes or polybutylenes having molecular weights in the range of 175 to 500. V

The reaction between phosphorus sulfides and polyolefins is well described in numerous patents, which set forth various reaction conditions.

However, for the new products described herein, it is preferred that the polyolefins and the phosphorus pentasulfide are used in molar ratios of about 2 mols of polyolefins per mol of phosphorus sulfide. For the purpose of simplicity, the product obtained by reacting phosphorus pentasulfide and the polyolefin will be termed herein a phosphosulfurized polyolefin.

The phosphosulfurized polyolefin is reacted with chloral in equivalent proportions at temperatures ranging from 25 C. to 150 C. The resulting acidic product is neutralized with a basic zinc compond, such as zinc oxide or zinc hydroxide, to form the zinc salt. It is this zinc salt which is the extreme pressure agent of this invention. 1

The phosphosulfurized polyolefins are prepared by reacting the polyolefins and the phosphorus pentasulfide at temperatures ranging from 120 C. to 290 C., preferably from 150 C. to 240 C.

The-reaction of the phosphosulfurized polyolefin with chloral can best be done at 0 C. to 150 C., more prefer: abiy, 100 C. to 140 C.

The phosphosulfurized polyolefin-chloral acidic product can be neutralized with zinc oxide (or hydroxide) at temperatures of 50 C. to 75 C. to form the zinc salt thereof, which zinc salt is the extreme pressure agent of this invention.

The zinc salt described hereinabove is used in lubricating oil compositions in amount sufiicient to impart extreme pressure characteristics thereto, that is, in amounts from about 0.1%, by weight, to about 25%, by weight. The zinc salt is preferably used in amounts of 1.0% to 15% by weight.

Thus, the lubricating oil compositions of this invention have incorporated therein a zinc salt of a phosphosulfurized-polyolefin-chloral reaction product which zinc salt is obtained by reacting zinc oxide (or hydroxide) at 50 to C. with a phosphosulfurized polyolefin-chlora1 product prepared by reacting a phosphosulfurized-polyolefin with chloral in equivalent proportions at temperatures from 0 C. to C.

Lubricating oils which can be used as base oils include a wide variety of lubricating oils, such as naphthenic base, paramn base, and mixed base lubricating oils, other hydrocarbon lubricants, e.g., lubricating oils derived from coal products, and synthetic oils, e.g., 'alkylene polymers (such as polymers'of propylene, butylene, etc.,"and the mixtures thereof), alkylene oxide-type polymers (e.g., propylene oxide polymers) and derivatives, includingalkyleue oxide polymers prepared by polymerizing the alkylene oxide in the presence of water or alcohols, e.g., ethyl alcohol, dicarboxylic acid esters (such as those which are prepared by esterifying such dicarboxylic acids as adipic acid, azelaic acid, suberic acid, sebacic acid, alkanol succinic acid, fumaric acid, maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol, Z-ethyl hexyl alcohol, dodecyi alcohol, etc.) liquid esters of acids of phosphorus, akyI'benzenes (e.g., monoalkyl benzene such as dodecyl benzene, tetradecyl benzene, etc.), and dialkyl benzenes (e.g., n-nonyl 2-ethyl hexyl benzene); polyphenyls (e.g., biphenyls and terphenyls), alkyl biphenyl ethers, polymers of silicon (e.g., tetraethyl silicate, tetraisopropyl silicates, tetra(4-methyl-2-tetraethyl) silicate, hexyl (4-methyl-2-pentoxy)disiloxane, poly(methyl) siloxane, poly(methylphenyl) siloxane, etc.). Synthetic oils of the alkylene oxide-type polymers which may be used include those exemplified by the alkylene oxide polymers.

The above base oils may be used individually or in combinations thereof, whenever miscible or wherever made so by the use of mutual solvents.

The examples set forth hereinbelow describe the preparation of the extreme pressure agents of this invention.

EXAMPLE 1 Preparation of Phosphosulfurized Polybutene and found to contain:

Phosphorus percent by weight 2.67 Sulfur do 7.33 Atomic ratio, S/P 2.57

EXAMPLE 2 Preparation of ihe Zinc Salt of Phosphosulfurized Polybutene A mixture of 1,000 grams (0.875 g.-atoms phosphorus) of the filtered reaction product of Example 1 hereinabove, and 126.3 grams (0.857 mol) of chloral was blended with agitation and heated at the following temperatures during the noted periods of time:

Time, hrs: Temp. C. 0.0 40 0.25 100 2.0 137 2.25 145 3.0 55

After the three-hour period, the mixture was cooled to room temperature, after which 36.5 grams (0.449 mol) of zinc oxide was added. On this addition, the temperature rose to 76 C. The mixture was then agitated for a period of about 2 hours at 75 C. to complete the reaction.

The contents of the reaction flask, after standing overnight at room temperature, were heated to a temperature of 70 C. liquid temperature at 7 mm. Hg absolute pressure. The fluid remaining in the reaction vessel was a dark, oil-soluble liquid which was found on analysis to contain:

Phosphorus, wt. percent 2.04, 2.02

Sulfur, wt. percent 6.06, 6.12

Zinc, wt. percent 1.99, 2.01

Chlorine, wt. percent 7.4, 7.1

Atomic ratios: PLQO, S2 90, ZHOAGB, C1342- Acid number (Mg KOH/g.) 24.2

EXAMPLE 3 Preparation of Ph'osphosulfurized Polypropylene A mixture of 729.2 grams (4.00 mols) of propylene tetramer (mol wt. 182.3) and 446.5 grams (2.01 mols) of phosphorus pentasulfide was heated from 75 C. to

138 C. during a 2-hour period, followed by heating to a temperature of 150 C. during an additional 3.5 hours. The contents of the reaction vessel were filtered through Celite filter aid, and the clear filtrate, approximately 1,165 grams, was analyzed and found to contain:

Phosphorus, wt. percent 9.52 Sulfur, wt. percent 25.8, 26.2 Atomic ratio, S/P 2.64 Density, 20/4 1.0814 Refractive index, n 1.5778

The resulting material was soluble in a solvent refined Mid-Continent base SAE 30 oil at a temperature of about 180 F., but practically insoluble at room temperature.

Example 4 Reaction of Phosphosulfurized Polypropylene With Chloral and Zinc Oxide A mixture of 239.5 grams (0.735 g.-atoms phosphorus) of the phosphosulfurized polypropylene from Example 3 hereinabove and 123.7 grams (0.840 mol.) of freshly distilled chloral was blended at 70 C. The resulting exothermic reaction raised the temperature with water bath cooling to C. The mixture was then heated at temperatures ranging from C. to C. for a period of about 3 hours during which time the color of the mixture changed from a light yellow to a dark red. The reaction product was cooled to 50 C., at which temperature 36 grams (0.4420) of zinc oxide was added. It was necessary to apply cooling to keep the temperature at about 65 C. The temperature was kept at that point for about 1.5 hours, after which the product was heated at 75 C. liquid temperatures and absolute pressure of 25 mm. Hg to remove water and unreacted chloral or chloral hydrate. The reaction mixture was then filtered through Celite filter aid, yielding a clear, dark viscous liquid, which, on analysis, was found to contain:

A mi ratios! rom 2.02 0.495 2.87-

In an amount of 10%, by weight, this zinc salt was insoluble in a solvent refined Mid-Continent SAE 30 oil, and in a California parafiinic base oil having a viscosity of 895 SSU at 100 F. However, in an amount of 10%, by Weight, this zinc reaction product was soluble in Dow Polyglycol 144, a mixed poly (ethylene, propylene) glycol 2-ethyl hexyl methyl diether having a molecular weight of about 400. This oil is sold by Dow Chemical Company.

Table I hereinbelow presents extreme pressure data obtained by the Federal Test Method Standard No. 791, using a Shell 4-Ball Tester, with the exception that the tests herein were run at 500 r.p.m. instead of the specified 1,000 r.p.m.

The additives were present in the lubricating oil composition in an amount sufficient to provide 0.10 gram atom phosphorus per liter of lubricating oil composition.

The base oil was a California paraflin base oil having a viscosity of 95 SSU at 210 F. (viscosity index=85).

Additive A was a zinc di(alkylphenyl) dithiophosphate wherein the alkyl radicals were derived from propylene polymers having an average of about 12 carbon atoms.

Additive B was a zinc salt of a mixed dialkyl dithiophosphoric acid wherein one of the alkyl radicals contained 4 carbon atoms and the other alkyl radical contained 6 carbon atoms.

Additive C was a zinc mixed dialkyl dithiophosphate wherein one of the alkyl radicals contained 4 carbon atoms and the other alkyl radical contained 5 carbon atoms.

Additive D was the zinc salt obtained in Example 2 hereinabove.

TABLE I Load at failure, Test No Additive pounds 1 None 85 A 210 B 335 C 325 D 410 Table II hereinb'elow presents data showing fiurther the effectiveness of the zinc salts herein as wear reducing agents as determined by the Falex test, which is described in Journal of the Institute of Petroleum, volume 32, April 1946. The test assembly consisted of a steel rod inserted between two steel Vashaped bearing blocks. The assembly bearing blocks and rod were immersed in the lubricating oil being tested. The rod was rotated and, as the rod rotated, progressively increasing pressures were applied upon the rod by the V-shaped bearing block' until seizure occurred. The numerical figures of table II are the recorded Falex values at which seizure occurred; that is, the loads under which the particular lubricating oil compositions failed.

The base oil was Squibbs White Oil, and the additive level was such as to provide 0.01 gram. atom of phosphorus per liter of oil composition.

The lubricating oil compositions described herein are not only highly effective'under conditions of high pressure, that is, Where extreme pressure characteristics are desired, but these lubricating oil compositions are also highly resistant to oxidation. The anti-oxidation properties of these lubricating oil compositions were evaluated in tests wherein the oxidation inhibition periodwas determined. The data are presented hereinbelow in table 111.

By this oxidation test, the lubricating oil composition was placed in a large glass tube equipped with a high speed glass stirrer, incorporating therein as oxidation catalysts several metal naphthenates in amounts suificient to provide the metal concentration as follows:

The oil temperature was maintained at 340 F., at a pure oxygen pressure of about 1 atmosphere. The inhibition period was the time in hours required for 100 grams of oil to absorb 1200 cc. of oxygen. The inhibition period for the base oil is typically to 30 minutes in this test.

Base oil A, which was a blend of Mid-Continent paraffin base oils, had a viscosity of 127.3 SSU at 100 F., and 41.3 SSU at 210 F. The viscosity index was 89.4.

Base oil B was the Dow-Polyglycol 144 described hereinabove.

Additive A was a commercial lubricating oil additive concentrate when used in the amount noted, provided in the finished oil composition 0.4%, by weight, of a commercial oxidation inhibitor, about 0 .5%, by Weight, of a corrosion inhibitor, and 4.67 rum/kg. (millirnols per kilogram oi finished oil, based on the zinc) of a zinc mixed dialkyl dithiophosphate wherein one alkyl radical alkyl radical con- TABLE III Test No l0 11 12 Temperature, "F 340 340 340 Lube Oil Composition, weight percentase oil A 81.2 78. 2 Base Oil B. 83.2 Additive A. 6. 8 6. 8 6. 8

Additive B 12.0

Additive C 15.0 Additive D 10. 0 Inhibition period, hours 4. 5 7. 2 1.9

I claim:

1. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity selected from the group consisting of mineral oil and synthetic oil and mixtures thereof, and from 0.1% to 25%, by weight, of a zinc salt of a phosphosulfurized polyolefin-chloral reaction product, which product is obtained by reacting in equivalent molar amounts a phosphosulfurized polyolefin with chloral at temperatures in the range of 0 C. to 150 C., where said phosphosulfurized polyolefin is a product obtained by reacting phosphorus pentasulfide with a polyolefin at temperatures in the range of about 120 C. to about 290 C. wherein the phosphorus pentasulfidepolyolefin niol ratio is 1:2, and said polyolefin is selected from the group consisting of polypropylene and polybutylene having molecular weights fromabout 175 to about 500. t

2. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity selected from the group consisting of mineral oil and synthetic oil and mixtures thereof, and from 0.1% to 25 by weight, of a zinc salt of a phosphosulfurized polyolefin-chloral reaction product, which product is obtained by reacting in equivalent molar amounts a phosphosulfurized polyolefin with chloral at temperatures in the range of C. to 140 C., where said phosphosulfurized polyolefin is a product obtained by reacting phosphorus pentasulfide with a poly-olefin at temperatures in the range of about C. to about 290 C. wherein the phosphorus pentasulfidepolyolefin mol ratio is 1:2, and said polyolefin is selected from the group consisting of polypropylene and polybutylene having molecular Weights from about 175 to about 500.

3. A lubricating oil composition having extreme pressure characteristics comprising a major proportion of an oil of lubricating viscosity selected from the group consisting of mineral oil and synthetic oil and mixtures thereof, and from about 1% to about 15%, by weight, of a zinc salt of a phosphosulfurized polyolefin-chloral reaction product, wherein the reaction product is obtained by reacting, in equivalent molar amounts, chloral with a phosphosulfurized polyolefin at temperatures from about 100 C. to about (1., wherein said phosphosulfurized polyolefin is prepared by reacting 2 mob of a polyolefin selected from the group consisting of polypropylene and polybutylene having a molecular Weight from about to about 500 with 1 mol of phosphorus pentasulfide at temperatures from about 120 C. to about 280 C.

4. A lubricating oil composition consisting essentially of an oil of lubricating viscosity selected from the group consisting of mineral oils and synthetic oils and mixtures thereof and from about 0.1% to about 25%, by weight, of a zinc salt of a phosphosulfurized polyolefin-chloral product, which product is obtained by reacting, in equivalent molar amounts, 9. phosphosulfurized polyolefin with chloral at temperatures of 100 C. to 140 C., wherein said phosphosulfurized polyolefin is a product obtained by reacting P S with a polyolefin, wherein the phosphorus pentasulfidepolyolefin mol ratio is 1:2 and wherein said polyolefin in a polybutene having molecular weight in the range of about 175 to about 500 and wherein said P S -polyolefin reaction is at temperatures in the range of 120 C. to about 290 C.

5. A lubricating oil composition consisting essentially of a petroleum base oil and from about 0.1% to about 25 by Weight, of a zinc salt of a phosphosulfurized polyolefin-choral product, which product is obtained by reacting, in equivalent molar amounts, a phosphosulfurized polyolefin with choral at temperatures of 100 C. to 140 C., wherein said phosphosulfurized polyolefin is a product obtained by reacting P S with a polyolefin, wherein the phosphorus pentasulfide-polyolefin mol ratio is 1:2 and wherein said polyolefin is a polybutene having molecular weight in the range of about 175 to about 500 and wherein said P S -polyolefin reaction is at temperatures in the range of 120 C. to about 290 C.

6. A lubricating oil composition consisting essentially of a petroleum base oil and from about 0.1% to about 25%, by weight, of a zinc salt of a phosphosulfurized polyolefin-choral product, which product is obtained by reacting, in eqivalent molar amounts, a phosphosulfurized polyolefin with choral at temperatures of 100 C. to

140 C., whereinsaid phosphosulfurized polyolefin is obtained by reacting 1 mol of phosphorus pentasulfide with 2 mols of a polybutene having a molecular weight of about 175 to about 500 at temperatures in the range of 120 C. to about 280 C.

7. A lubricating oil composition consisting essentially of a petroleum base oil and from about 0.1% to about by weight of a zinc salt of a phosphosulfurized polyolefin-chloral product, which product is obtained by reacting (A) phosphorus pentasulfide with a polybutene having a molecular Weight of about 175 to about 500 at temperatures in the range of C. to about 280 C., wherein the phosphorus pentasulfide polybutene mol ratio is 1:2, (B) reacting a product from (A) with chloral in equivalent molar amounts at temperatures of 100 C. to about C., (C) reacting the product of (B) with zinc oxide to form the zinc salt thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,444,948 Musselman et a1 July 13, 1948 2,703,784 Fields Mar. 8, 1955 2,727,030 Beretvas Dec. 13, 1955 2,827,433 Fischl et a1 Mar. 18, 1958 2,833,714 Richardson et a1 May 6, 1958 2,939,841 Buckrnan June 7, 1960

Claims

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF AN OIL OF LUBRICATING VISCOSITY SELECTED FROM THE GROUP CONSISTING OF MINERAL OIL AND SYNTHETIC OIL AND MIXTURES THEREOF, AND FROM 0.1% TO 25%, BY WEIGHT, OF A ZINC SALT OF A PHOSPHOSULFURIZED POLYOLEFIN-CHLORAL REACTION PRODUCT, WHICH PRODUCT IS OBTAINED BY REACTING IN EQUIVALENT MOLAR AMOUNTS A PHOSPHOSULFURIZED POLYOLEFIN WITH CHLORAL AT TEMPERATURES IN THE RANGE OF 0*C. TO 150*C., WHERE SAID PHOSPHOSULFURIZED POLYOLEFIN IS A PRODUCT OBTAINED BY REACTING PHOSPHORUS PENTASULFIDE WITH A POLYOLEFIN AT TEMPERATURES IN THE RANGE OF ABOUT 120*C. TO ABOUT 290*C. WHEREIN THE PHOSPHORUS PENTASULFIDEPOLYOLEFIN MOL RATIO IS 1:2, AND SAID POLYOLEFIN IS SELECTED FROM THE GROUP CONSISTING OF POLYPROPYLENE AND POLYBUTYLENE HAVING MOLECULAR WEIGHTS FROM ABOUT 175 TO ABOUT 500.