US3565803A - Reaction product of an alkali metal anion of a ketone and an acrylonitrile as a lubricating oil detergent - Google Patents

Abstract

DIALKYL KETONES HAVING A RELATIVELY LONG OIL SOLUBLE ALKYL GROUP ARE CONDENSED AS THEIR ANIONS WITH AN ACRYLONITRILE UNDER MILD CONDITIONS TO PROVIDE LUBRICATING OIL DETERGENT ADDITIVES AND EMULSIFIERS.

Description

United States Patent O 3,565,803 REACTION PRODUCT OF AN ALKALI METAL ANION OF A KETONE AND AN ACRYLONI- TRILE AS A LUBRICATING OIL DETERGENT Louis de Vries, Richmond, Calif., assignor to Chevron Research Company, San Francisco, Calif., a corporation of Delaware No Drawing. Filed Aug. 1, 1968, Ser. No. 749,314 Int. Cl. Cm 1/20, 1/32, 1/54 US. Cl. 252-42.7 1 Claim ABSTRACT OF THE DISCLOSURE Dialkyl ketones having a relatively long oil soluble alkyl group are condensed as their anions with an acrylonitrile under mild conditions to provide lubricating oil detergent additives and emulsifiers.

BACKGROUND OF THE INVENTION Field of the invention The modern lubricating oil contains detergents and dispersants to prevent the formation of deposits and the depositing of sludge in internal combustion engines. To be an acceptable detergent, not only must the detergent additive have good detersive capability, but its decomposition products should not enhance the formation of deposits.

Moreover, because of usual marketing practices, the additives should be effective over a broad range of conditions: the additives should be stable under the hot conditions of the diesel engine, as well as provide detergency and dispersancy over the more variable temperature conditions in the automobile engine.

The detergent must not have deleterious effects, such as corrosion, oxidation initiation, etc., which cannot be easily and economically inhibited. Also, any additive which is used in lubricating oils, which are frequently heavily compounded, must be compatible with the other additives included in the oils. These additives are oxidation inhibitors, viscosity index improvers, corrosion inhibitors, extreme pressure additives, etc.

Description of the prior art Numerous patents have issued on ashless detergents having nitrogen as the polar portion of the molecule. These patents include US. Pat. No. 3,219,666, which is concerned with carboxamides of polyamines; US. Pat. No. 3,275,554, which is concerned with hydrocarbon substituted alkylene polyamines; and US. Pat. No. 3,328,297, which is concerned with aliphatic sulfamides of polyalkylene polyamines.

These ashless detergents show excellent detersive capability while avoiding the presence of metals which tend to result in metal deposits.

SUMMARY OF THE INVENTION Pursuant to this invention, lubricating oil detergents and emulsifiers are prepared by combining the anion of a dialkyl ketone, having a relatively long chain alkyl group with an acrylonitrile under mild conditions, wherein at least 1 acrylonitrile molecule is condensed onto the dialkyl ketone.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The compositions of this invention are prepared by combining the a-anion of a dialkyl ketone of at least 30 carbon atoms and, preferably, of at least 50 car-bon atoms, having a hydrocarbon chain of at least 25 carbon atoms, with an acrylonitrile at moderate temperatures for a time 3,565,803 Patented Feb. 23, 1971 o (RgCR RQ M wherein M is an alkali metal of atomic number in the range of 3 to 19 (lithium, sodium and potassium), more usually in the range of 11 to 19, preferably sodium; R is an oil solubilizing aliphatic group of at least 25 carbon atoms and usually of at least 45 carbon atoms and up to 200 carbon atoms; R and R are hydrogen or lower alkyl of from 1 to 3 carbon atoms, more usually hydrogen.

Depending on R, R and R the proton may be removed from the R group alpha to the carbonyl to give an anion of the formula t"? R'o-d-orr-Ra eMe19 wherein M, R and R are as defined previously and RI! min is equivalent to R. Alternatively the anion may be a mixture of the two possible anions. Depending on the rate at which the two anions react with acrylonitrile, one or two products may result. When R is disubstituted alpha to the carbonyl or highly hindered at the alpha position, only one anion will result.

In referring to acrylonitrile, it is intended to include a-alkyl substituted acrylonitriles where the alkyl group is of from 1 to 2 carbon atoms, i.e., methyl or ethyl. These acrylonitriles have the formula CH =O wherein Y is hydrogen or alkyl of from 1 to 2 carbon atoms, preferably hydrogen.

The acrylonitrile will be used in an amount of at least 1 mole of acrylonitrile per mole of anion and usually not exceeding 10 moles, more usually in the range of 1 to 6 moles, and, preferably, in the range of 2 to 5 moles.

The acrylonitrile may be added batchwise or incrementally to the anion. Preferably, the acrylonitrile is added incrementally with vigorous stirring so as to obtain relatively homogeneous diffusion of the acrylonitrile into the reaction mixture. Usually, the reaction is carried out in an inert solvent. These solvents may be polar or nonpolar (hydrocarbon).

Illustrative hydrocarbon solvents include benzene, toluene, cumene, tert.-butyl benzene, preferably, aromatic hydrocarbons of from 6 to 10 carbon atoms. Other solvents include ethers, both aliphatic and aromatic, etc. Individual solvents or mixed solvents may be used.

The concentration of the anion in the solvent may vary from 1 weight percent to weight percent, more usually of from about 10 to 70 weight percent.

The temperature for the condensation of the acrylonitrile with the anion will generally be at least 10 C. and usually of from about 0 to 60 C., preferably from about 10 to 45 C. Elevated temperatures are not desirable in that they may lead to undesirable poly-condensation products.

The time for the addition of the acrylonitrile to the anion will vary widely, depending on the method of addition, the amounts employed and the equipment available. Times may vary from 5 minutes to 24 hours, more usually being from about 30 minutes to 6 hours.

The final product will generally have at least about 3 0.5 weight percent nitrogen and more usually in the range of about 1 to 5 weight percent nitrogen.

The preparation of ketone anions is described in an article by Adams and Hauser, J. Am. Chem. Soc. 66 1220 (1944). The ketone anion can be prepared by the reaction of any convenient alkali metal base with a dialkyl ketone having at least 1 OL-hY'dIOgCII. Conveniently, the ketone can be reacted with an alkali metal amide or alkali metal hydride with escape of ammonia or hydrogen, respectively. Or, the ketone may be reacted with a metal complex, such as metal-aromatic hydrocarbon complexes, e.g., sodium naphthalene, sodium biphenyl, etc. Usually, from about 0.9 to 1.5 equivalents of the base will be added per mole of ketone.

Conveniently, the reaction is carried out in an inert solvent, usually an aromatic hydrocarbon solvent. The solvents have been described previously for use in the condensation of acrylonitrile and the anion. The temperature for the reaction will generally be in the range of about to 50 C. The concentration of the ketone in the solvent will generally be of from about 10 to 70- weight percent.

The reaction is easily followed by the evolution of gas. When no further gas is evolved, acrylonitrile, neat or in solution, may then be added to the anion. Isolation of the anion is not required.

The ketone used to form the anion is readily prepared by the ozonization of asymmetrical secondary olefins. By asymmetrical secondary olefins is intended an olefin being disubstituted on one of the ethylene carbon atoms. Of course, the olefin may be tertiary or quaternary, which inherently includes the secondary olefin.

The ketones which find use will, for the most part, have the following formula:

wherein R is an alkyl group of at least 25 carbon atoms, usually from about 45 carbon atoms to 200 carbon atoms. R is an oil solubilizing group, generally having at least Ibranch per 4 carbon atoms along the chain and more usually at least 1 branch per 2 carbon atoms along the chain. Particularly preferred groups are polypropenyl and polyisobutenyl obtained from polypropenyl and polyisobutenyl polymers. Other R groups may include ethylene/ propylene copolymers, ethylene-isobutylene copolymers, lbutene polymers, etc. Their branches will generally be of from 1 to 2 carbon atoms, more usually 1 carbon atom, i.e., methyl.

When ozonization is used as the method of preparation of the ketone, the ketone will generally be free of other sites of olefinic unsaturation. However, 1 or more sites of olefinic unsaturation may be present, when the other olefinic site is more highly hindered than the olefin, which it is desired to cleave.

Usually, no more than 1 site of unsaturation will be present, and more usually, the alkyl groups will be saturated.

R and R are hydrogen or lower alkyl of from 1 to 3 carbon atoms, usually of only 1 carbon atom and, preferably, hydrogen.

The method of ozonization is described in an article by J. J. Pappas, Tetrahedron Letters 36 4273 (1966). By this method, the olefin is dissolved in an inert solvent containing a hydroxylic solvent, such as methanol and ozone passed through the solution at temperatures below 0 C. When the equivalent amount of ozone has been introduced into the solution, the addition of ozone is stopped, and the solution sparged with nitrogen. Then 1 equivalent of methyl sulfide per equivalent of Olefin is added and the volatile materials stripped.

4 Examples The following examples are ofiered by way of illustration and not by way of limitation:

Example A.Into a 1-liter flask with fritted glass inlet was charged 120 g. of polyisobutylene (approximately 1,000 av. mol. wt.) in 400 ml. of dichloromethane containing 2 equivalent weights (based on polyisobutylene) of methanol. The solution was cooled to 20 C. and 1 equivalent weight of ozone sparged through the solution over a period of about 8 hours. At the end of this time, the ozone addition was stopped, and the solution sparged with nitrogen for 1 hour. To the solution was then added, in small excess over stoichiometric, 1 equivalent weight of dimethyl sulfide and the solution allowed to warm to room temperature. When sufiicient time had passed, the solvent was stripped under reduced pressure (2 mm. Hg), and the residue purified by twice reprecipitating in acetone from pentane.

The product was analyzed by an infrared spectrum which showed the characteristic carbonyl peak.

Example I.Into ,a reaction vessel was charged 1.4 g. of sodium amide in 50 ml. of benzene. To the mixture was added dropwise at room temperature 12 g. of a product prepared as described in Example A (ketone derived from polyisobutylene of approximately 1,000 average molecular weight) in 50 ml. of benzene; the mixture was stirred at room temperature for 20 hours. A slow evolution of gas occurred. At the end of this time, 1.91 g. of acrylonitrile in 60 m1. of ether was added, using rapid stirring and a dropping funnel with a capillary inlet extending under the surface of the liquid in order to obtain very slow and continuous addition. The product was then precipitated 3 times in methanol from a pentane solution.

An aliquot of the product was chromatographed on a small alumina column. The material which was eluted with pentane Weighed 4.2 g. (40.5 weight percent). The material eluted with 25 percent ether/ 75 percent pentane was 3.65 g. (35.2 weight percent). Finally, the product eluted with 5 percent methanol/ percent pentane was 2.5 g. (24.3 weight percent).

The analysis of the original product (unchromatographed) is as follows: C, 81.2%; H, 13.03%; N, 3.24%. p Example II.-Into a reaction vessel was introduced 500 g. of ketone derived from polyisobutylene of approximately 1,000 average molecular weight (prepared as described in Example A) in toluene. The toluene was azeotroped to remove any water. Nitrogen gas was introduced to provide a nitrogen atmosphere and 63.0 g. of sodium amide added, and the reaction mixture allowed to stir for 64 hours. The product was then filtered under nitrogen into a receiver and diluted to a total volume of 2.5 liters with toluene.

To the toluene solution was then added 79.5 g. of acrylonitrile in 1,500 ml. of toluene. The addition was carried out dropwise through a capillary with rapid stirring to provide a maximum dispersion of the acrylonitrile in the toluene solution. The reaction mixture remained clear throughout the addition. When the addition was complete, the solvent was stripped along with unreacted acrylonitrile, the pressure being reduced to 2 mm. Hg. The residue was then dissolved in pentane, the product reprecipita-ted with methanol, and the solid redissolved in pentane. The product was then isolated and analyzed: C, 80.6%; H, 12.61%; N, 3.82%; O, 3.6%.

Example III.-Into a reaction vessel was introduced 410 g. of a ketone derived from polyisobutylene of approximately 1,000 average molecular weight (prepared as described in 'Example A) in 1,000 ml. of benzene. To the solution under nitrogen was added 48 g. of sodium amide and the mixture allowed to stir for 24 hours, at which time the evolution of gas had ceased. The mixture was then filtered into a receiver under nitrogen and to the filtrate added dropwise 65.2 g. of acrylonitrile in 500 ml.

of benzene. Some heat of reaction was noticed, the temperature rising to a maximum of 35 C. At the end of the addition, the mixture was allowed to settle, filtered, the filtrate diluted with 4 volumes of pentane, then chilled to C. and filtered. The volatiles were removed by reducing the pressure to 2 mm. Hg. The residue was analyzed: C, 81.33%; H, 12.33%; N, 2.96%; O, 2.17%.

Example IV.-lnto a reaction vessel was introduced 25 ml. of dry tetrahydrofuran, 2.36 g. (1 equivalent weight) naphthalene and 0.425 g. (1 equivalent weight) sodium and the mixture stirred at room temperature for about one hour, when all of the sodium had dissolved. To the solution was then added 50 g. (1 equivalent weight) of a ketone derived from polyisobutylene of approximately 2,700 average molecular weight (prepared as described in Example A). When the color of the solution was discharged, 250 ml. of dry toluene was added.

While rapidly stirring the solution, 5.9 g. (6.0 equivalent weight) of acrylonitrile was added slowly. At the end of the addition, the mixture was stirred for an additional hour and then methanol added. The product was purified by repeated dissolving of the product in pentane and precipitation with methanol. The product was then isolated and freed of volatile materials.

USE OF THE COMPOSITIONS IN LUBRICATING OILS As already indicated, the compositions of this invention find use as detergents and dispersants in lubricating oil and are found to be effective under a wide variety of conditions; not only under the hot conditions of the diesel engine, but the much more variable temperature conditions of the automobile engine.

The compositions of this invention may be formulated with various lubricating fluids (hereinafter referred to as oils) which are either derived from natural or synthetic sources. Oils generally have viscosities of from about 35 to 50,000 Saybolt Universal Seconds (SUS) at 100 F.

Among natural hydrocarbonaceous oils are paraffin base, naphthenic base, asphaltic base and mixed base oils. Illustrative of synthetic oils are: hydrocarbon oils such as polymers of various olefins, generally of from 2 to 8 carbon atoms, and alkylated aromatic hydrocarbons; and non-hydrocarbon oils, such as polyalkylene oxides, aromatic ethers, carboxylate esters, phosphate esters, and silicon esters. The preferred media are the hydrocarbonaceous media, both natural and synthetic.

The above oils may be used individually or together whenever miscible or made so by the use of mutual solvents.

The detergents of this invention may be blended with lubricating oils in the amount of from 0.1 to 70 weight percent detergent. When the detergents are compounded with lubricating oils for use in an engine, the detergents will be present in at least about 0.1 Weight percent and usually not more than 20 weight percent, more usually in the range of about 1 to 10 weight percent. The compounds can be prepared as concentrates due to their excellent compatibility with oils. As concentrates, the compounds of this invention will generally range from about 10 to 70 weight percent, more usually from about to 50 weight percent of the total composition.

A preferred aspect in using the compounds of this invention in lubricating oils is to include in the oil from about 1 to 50 rnM./kg. of a dihydrocarbyl phosphorodithioate, wherein the hydrocarbyl groups are from about 4 to 36 carbon atoms. Usually, the hydrocarbyl groups will be alkyl or alkaryl groups. The remaining valence of the phosphorodithioate will usually be satisfied by Zinc, but polyalkyleneoxy or a third hydrocarbyl group may also be used. (Hydrocarbyl is an organic radical composed solely of carbon and hydrogen which may be aliphatic, alicyclic, aromatic or a combination thereof.)

Other additives may also be included in the oil such "as pour point depressants, oiliness agents, antioxidants,

rust inhibitors, etc. Usually, the total amount of these additives will range from about 0.1 to 10 weight percent, more usually fromabout 0.5 to 5 weight percent. The individual additives may vary from about 0.01 to 5 weight percent of the composition.

In order to demonstrate the effectiveness of the compositions of this invention under extremely severe engine conditions, the composition of Example II was compounded at 4 weight percent in a Mid-Continent SAE30 neutral oil. Also included were 12 mM./ kg. of a common oxidation inhibitor, zinc 0,0-dialkylphenyl phosphorodithioate (the alkyl groups are of from 12 to 15 carbon atoms).

The test used is a particularly severe test which is referred to as the 240-BMEP (Brake Mean Effective Pressure) Caterpillar Test. The conditions are for a supercharged Caterpillar Test, wherein the pressure of the supercharged air is 76.5 in. Hg abs., the water tem perature of the cooling jacket is 200 F., the air temperature is F., the oil temperature of the bearing is 190 F., the sulfur content of the fuel is 0.4 weight percent, the speed of the engine is 1,200 r.p.m., and the rate of fuel input is at a rate which provides 6,900 B.t.u.s per minute. The test was carried out for hours, the engine being rated at both 60 and 120 hours. The results are reported as follows:

Rated 0-100, 100 being completely clean, 0 being completely filled. 1 Rated 0-800, 800 being completely black.

The exemplary composition was also tested for its effect on piston varnish in what is referred to as a Ford varnish engine test. A highly compounded oil was used, having the following formulation: 14.7 weight percent of Example H; 50 mM./ kg. calcium as a calcium carbonate overbased calcium mahogany sulfonate; 15 mM./kg. of zinc, 0,0-dialkyl phosphorodithioate (alkyl of from 4 to 6 carbon atoms). The oil used was a mixture of Sunray DX 250 neutral oil and Sunray DX '150 bright stock in a 6.16/1 weight ratio.

The test was carried out with a 6-cylinder Ford having a 240 cubic inch displacement. The engine conditions are the same as the cyclic conditions of the ASTM sequence 5B test. The engine conditions are stressed by using a dirty fuel which is comprised of 30 volume percent of a FCC heavy cut having a boiling range of from 253 to 424 F. with 70 volume percent of a commercial regular grade gasoline. The fuel has 2 ml. per gallon of lead and approximately 0.1 weight percent sulfur. The crankcase depression is maintained at one inch water. The engine run is carried out for 60 hours.

The piston varnish rating was 6.3 on the basis of 0 to 10, 10 being clean. This compared favorably to commercially available ashless detergents in being a comparable varnish rating.

It is evident from the above results that the compositions of this invention are effective lubricating oil deter gents under extremely severe temperature and oxidative conditions. Furthermore, they are compatible with other common additives included in lubricating oil. The compositions are also emulsifiers and may be used to prepare water-in-oil emulsions.

I claim:

1. A lubricating oil composition having from 0.1 to 70 weight percent of a composition prepared by combining an alkali metal anion of a ketone of the formula:

0 R i /011mm wherein said alkali metal is lithium, sodium or potassium; R is an oil solubilizing aliphatic group of at least 28 carbon atoms; and R and R are hydrogen or lower 7 alkyl of from 1 to 3 carbon atoms, with from 1 to 10 3,451,931 6/1969 Kahn et a1. 2S249.7X moles of acrylonitrile per mole of anion, at a tempera- 3,453,212 7/1969 Dorer 25249.7 ture in the range of 10 to 60 C. for a time sufiicient to provide a product having at least 0.5 weight percent DANIEL WYMAN, Primary 'EXamlllel' mtrogen- 5 W. J. SHINE, Assistant Examiner References Cited US Cl XR UNITED STATES PATENTS 252 49 751 5 2,798,852 7/1957 Wiese et a1. 25242.7