Oil additive

Abstract

Compounds having the formula: ##SPC1## Wherein R'is selected from the group consisting of aliphatic hydrocarbon radicals containing about 8-100 carbon atoms, and hydrocarbylaminohydrocarbyl radicals having the formula: R.sub.1 --NR""--R.sub.2 -- wherein R.sub.1 is an aliphatic hydrocarbon radical containing about 8-100 carbon atoms, R"" is selected from the group consisting of hydrogen and C.sub.1-4 alkyls and R.sub.2 is a divalent aliphatic hydrocarbon radical containing about 2-10 carbon atoms, R.sub.3 and R.sub.4 are selected from the group consisting of hydrogen and alkyl radicals containing about 1-4 carbon atoms, R" is selected from the group consisting of hydrogen and C.sub.1-4 alkyls and R"' is selected from the group consisting of hydrogen and salt cations, are effective antiwear and antirust additives in lubricating oils and greases.

Parent Case Text

This application is a division of application Ser. No. 348,625, filed April 6, 1973, now U.S. Pat. No. 3,833,496.

Description

BACKGROUND

Additives are conventionally added to lubricating oil and grease to improve their properties. Antiwear additives used in the past include compounds such as zinc dialkyldithiophosphates, sulfurized sperm oil, and the like. Antirust protection can be provided by compounds such as overbased calcium sulfonates. Long chain amines such as polybutenyl ethylenediamine have been used to improve dispersancy of lubricating oils.

SUMMARY OF THE INVENTION

According to the present invention, lubricating oils and greases having improved antiwear and antirust properties are provided by including in the lubricating oil composition certain 3-mercaptoalkanoic acid, [(alkylamino)alkyl] dithiocarbamates such as 3-mercaptobutyric acid, [3(oleylamino)-propyl] dithiocarbamate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the invention is an antiwear-antirust additive for lubricating oils and greases having the formula: ##SPC2##

Wherein R' is selected from the group consisting of aliphatic hydrocarbon radicals containing about 8-100 carbon atoms, and hydrocarbylaminohydrocarbyl radicals having the formula:

R.sub.1 --NR""--R.sub.2 --

wherein R.sub.1 is an aliphatic hydrocarbon radical containing about 8-100 carbon atoms, R"" is selected from the group consisting of hydrogen and C.sub.1-4 alkyls and R.sub.2 is a divalent aliphatic hydrocarbon radical containing about 2-10 carbon atoms, R.sub.3 and R.sub.4 are selected from the group consisting of hydrogen and alkyl radicals containing about 1-4 carbon atoms, R" is selected from the group consisting of hydrogen and C.sub.1-4 alkyls and R"' is selected from the group consisting of hydrogen and salt cations. Useful salt cations include the cations of the alkaline earth metals such as calcium, magnesium, strontium, and barium; ammonium ions formed from ammonia; alkyl and alkenyl amines such as methylamine, dimethylamine, trimethylamine, triethylamine, tributylamine, ethanolamine, diethanolamine, triethanolamine, morpholine, stearylamine, oleylamine, palmylamine, laurylamine, eicosylamine, eicosenylamine, and the like; and other metal cations such as zinc, aluminum, nickel, manganese, iron, and the like.

Representative examples of the above additives include:

3-mercaptopropionic acid, n-octyldithiocarbamate

3-mercaptobutyric acid, stearyldithiocarbamate

calcium 3-mercaptobutyrate, oleyldithiocarbamate

zinc 3-mercaptopropionate, palmyldithiocarbamate

trimethylammonium 3-mercaptohexanoate, C.sub.100 -polybutenyl dithiocarbamate

manganese 3-mercaptobutyrate, stearyldithiocarbamate

barium 3-mercaptoheptanoate, eicosyldithiocarbamate

magnesium 3-mercaptobutyrate, eicosenyldithiocarbamate

triethanolammonium 3-mercaptobutyrate, oleyldithiocarbamate

A most preferred embodiment of this invention is an antiwear-antirust additive for lubricating oils and greases, said additive having the formula: ##SPC3##

wherein R.sub.1 is an aliphatic hydrocarbon radical containing from about 8-100 carbon atoms, R.sub.2 is a divalent aliphatic hydrocarbon radical containing from 2 to about 10 carbon atoms, and R.sub.3 and R.sub.4 are selected from the group consisting of hydrogen and alkyl radicals containing 1 to about 4 carbon atoms. Since the compounds contain both a basic amine functional group and a carboxylic acid they can exist in the form of a zwitterion and are shown in that form in Formula II.

Representative examples of such additives include:

3-mercaptopropionic acid, [2(9-eicosenylamino)ethyl]dithiocarbamate

3-mercapto-2-methylbutyric acid, [6(octylamino)hexyl]dithiocarbamate

3-mercaptoheptanoic acid, [10(laurylamino)decyl]dithiocarbamate

3-mercapto-2-methylhexanoic acid, [4(1-hexylbutylamino) butyl] dithiocarbamate

3-mercapto-2-butylheptanoic acid, [3(pentacontenylamino) propyl] dithiocarbamate

3-mercaptobutyric acid, [2(hexacontylamino)ethyl]dithiocarbamate

3-mercaptopropionic acid, [3(octacontylamino)propyl]dithiocarbamate

3-mercaptohexanoic acid, [3(C.sub.100 -polybutenylamino) propyl] dithiocarbamate

3-mercaptobutyric acid, [3(C.sub.90 -polypropenylamino) propyl] dithiocarbamate

3-mercaptooctanoic acid, [3(dodecenylamino)butyl]dithiocarbamate

3-mercaptopropionic acid, [3(tetracosylamino)propyl]dithiocarbamate

3-mercaptobutyric acid, [6(stearylamino)hexyl]dithiocarbamate

3-mercaptopentanoic acid, [4(palmylamino)butyl]dithiocarbamate

3-mercaptobutyric acid, [3(2-nonacontenylamino)propyl]dithiocarbamate

A preferred class of additives are those of Formula II wherein R.sub.1 contains about 8-22 carbon atoms, R.sub.2 is the trimethylene radical --(CH.sub.2).sub.3 --, R.sub.3 is the methyl radical, and R.sub.4 is hydrogen. Examples of these compounds are:

3-mercaptobutyric acid, [3(oleylamino)propyl]dithiocarbamate

3-mercaptobutyric acid, [3(stearylamino)propyl]dithiocarbamate

3-mercaptobutyric acid, [3(palmylamino)propyl]dithiocarbamate

The additives are readily prepared by reacting an aliphatic hydrocarbylaminohydrocarbylamine with carbon disulfide to form the corresponding hydrocarbylaminohydrocarbyl dithiocarbamic acid and reacting this with an appropriate alpha-unsaturated aliphatic carboxylic acid such as acrylic acid, crotonic acid, .alpha.-methyl crotonic acid, .alpha.,.beta.-diethyl acrylic acid, .beta.-butyl acrylic acid, .alpha.-butyl acrylic acid, and the like (N. Kreutzkamp et al, Arch. Pharm. 304, p. 477-481, July 1971).

The aliphatic hydrocarbylaminohydrocarbylamines can be prepared by reacting an aliphatic hydrocarbyl chloride with an aliphatic diamine. For example, reaction of oleyl chloride with 1,3-propanediamine yields oleylaminopropylamine. Likewise, reaction of lauryl chloride with 1,6-hexanediamine forms laurylaminohyexylamine. Similarly, reaction of C.sub.100 -polybutenyl chloride with ethylenediamine forms C.sub.100 -polybutenylaminoethylamine. The polyolefin chlorides are readily formed by reacting a polyolefin (e.g., polypropylene, polybutene, and the like) with chlorine.

The following example illustrates the manner in which the additives can be prepared.

EXAMPLE 1

To a solution of 175 grams of N-oleyl-1,3-propanediamine and 175 grams of isopropyl alcohol was added a solution of 40 grams of carbon disulfide and 40 grams of isopropyl alcohol over a one hour period at 0.degree.-10.degree.C. The unreacted carbon disulfide was distilled off and 50 grams each of crotonic acid, isopropyl alcohol and methanol was added. The mixture was stirred at 0.degree.-10.degree.C for 2 hours and then allowed to warm to room temperature. The product was diluted with hexane and washed with water, following which volatile material was distilled out under vacuum to yield 184 grams of a low melting solid.

EXAMPLE 2

A portion of the product from Example 1 was diluted with hexane, filtered, water washed, and then the hexane distilled out. The resultant product was diluted with neutral mineral oil to obtain a 67 weight percent active concentrate. This was diluted with hexane and washed with aqueous ammonia. Powdered solid carbon dioxide was added and stirred into the mixture. The mixture was then water washed, following which hexane was distilled out, leaving a viscous yellow liquid concentrate.

Modification of the above procedure by substitution of different starting hydrocarbylaminohydrocarbylamines and different alpha-unsaturated aliphatic carboxylic acids will lead to the other additives within the scope of this invention.

The additives are useful in lubricating oils and greases including both mineral and synthetic. Synthetic oils include polyolefin oils (e.g., polybutene oil, decene oligomer, and the like), synthetic esters (e.g., dinonyl sebacate, trioctanoic acid ester of trimethylolpropane, and the like), polyglycol oils, and the like. Greases are made from these oils by adding a thickening agent such as sodium, calcium, lithium, or aluminum salts of fatty acids such as stearic acid. The oils and greases are prepared by blending an antiwear and antirust amount of the additive into the oil or grease. A useful concentration is from about 0.1 to 5 weight percent. The additives may be added in the form of a concentrate such as the mineral oil diluted concentrate described in Example 2.

Other additives may be included in the oil or grease compositions. These include such additives as zinc dialkyldithiophosphates, barium phenates, calcium phenates, calcium aryl sulfonates, magnesium aryl sulfonates, overbased calcium aryl sulfonates, barium polybutenyl phosphonates; antioxidants such as 4,4'-methylenebis(2,6-di-tert-butylphenol), .alpha.-dimethylamino-2,6-di-tert-butyl-p-cresol; dispersants such as polybutenyl succinimides of ethylenepolyamines, polybutenyl ethylenediamines, viscosity index improvers such as polybutenes, ethylene-propylene copolymers, polylauryl methacrylates, and the like.

Tests have been carried out to demonstrate the antiwear and antirust properties of the additives. The first is known as the "four-ball cam and tappet test". In this test, three steel balls are placed in a triangular manner in a circular retainer containing the test oil. A fourth ball is placed on top of these three to form a triangular pyramid. A 50 Kg load is placed on the top ball and it is rotated at 1800 r.p.m. for one hour with the oil heated to 110.degree.C. This test has previously been shown to correlate well with the cam and tappet wear of an internal combustion engine. Criteria is the average scar diameter formed on the three bottom balls. A scar diameter of 1 mm or less is considered satisfactory.

The test was carried out on a non-additive neutral oil and on triplicate samples containing 1 weight percent of the additive of Example 1 -- 3-mercaptobutyric acid, [3(oleylamino)propyl] dithiocarbamate. The results obtained were as follows.

TABLE 1 ______________________________________ Additive Average scar diameter (mm) ______________________________________ None 2.3 Example 1 (1%) 0.92, 0.99, 0.89 ______________________________________

The antirust property of the additives was determined using the ASTM D-665 spindle rust test. In this test, spindles are rotated in a mixture of oil and synthetic seawater at 140.degree.F for 24 hours. The spindles are rated "pass" or "fail". A "pass" rating requires that the spindle be rust-free. This test was carried out using two non-additive mineral oil samples and four samples of the same mineral oil containing 1 weight percent of the concentrate of Example 2. The results were as follows.

TABLE 2 ______________________________________ Additive Results ______________________________________ None both fail Example 2 (1%) all pass ______________________________________

These results demonstrate the excellent antiwear and antirust properties of the present additives.

Claims

I claim:

1. An antiwear-antirust additive for lubricating oils and greases, said additive having the formula: ##SPC4##

wherein R' is selected from the group consisting of aliphatic hydrocarbon radicals containing about 8-100 carbon atoms, and hydrocarbylaminohydrocarbyl radicals having the formula:

R.sub.1 --NR""--R.sub.2 --

wherein R.sub.1 is an aliphatic hydrocarbon radical containing about 8-100 carbon atoms, R"" is selected from the group consisting of hydrogen and C.sub.1-4 alkyls and R.sub.2 is a divalent aliphatic hydrocarbon radical containing about 2-10 carbon atoms, R.sub.3 and R.sub.4 are selected from the group consisting of hydrogen and alkyl radicals containing about 1-4 carbon atoms, R" is selected from the group consisting of hydrogen and C.sub.1-4 alkyls and R"' is selected from the group consisting of hydrogen and salt cations.

2. An antiwear-antirust additive of claim 1, said additive having the formula: ##SPC5##

wherein R.sub.1 is an aliphatic hydrocarbon radical containing from about 8-100 carbon atoms, R.sub.2 is a divalent aliphatic hydrocarbon radical containing from 2 to about 10 carbon atoms, and R.sub.3 and R.sub.4 are selected from the group consisting of hydrogen and alkyl radicals containing 1 to about 4 carbon atoms.

3. An additive of claim 2 wherein R.sub.1 contains about 8-22 carbon atoms, R.sub.2 is the trimethylene radical, R.sub.3 is the methyl radical, and R.sub.4 is hydrogen.

4. An additive of claim 3 wherein R.sub.1 is the oleyl radical.

5. An additive of claim 3 wherein R.sub.1 is the stearyl radical.

6. An additive of claim 3 wherein R.sub.1 is the palmyl radical.