CA1139740A

CA1139740A - Oil-soluble friction-reducing additive and lubricating oil composition

Info

Publication number: CA1139740A
Application number: CA000350389A
Authority: CA
Inventors: Andrew G. Papay; Joseph P. O'brien
Original assignee: COOPER (EDWIN) Inc
Current assignee: COOPER (EDWIN) Inc
Priority date: 1979-05-18
Filing date: 1980-04-22
Publication date: 1983-01-18
Also published as: EP0020037A1; JPH0142997B2; JPS5626996A; DE3068942D1; EP0020037B1

Abstract

Abstract Additives are provided for lubricants, or fuels for internal combustion engines. They are oil-soluble aliphatic hydrocarbyl-substituted succinimide or succin-amide materials, wherein the hydrocarbyl group contains about 12 to 36 carbon atoms and is preferably derived from an isomerized straight chain .alpha.-olefin.

Description

~,~39740 1 Case C-4291 OIL-SOLUBLE FRICTION-REDUCING
ADDITIVE AND LUBRICATING OIL COMPOSITION
-This invention is in the field of lubricants and lubricant additives. More particularly, the invention deaIs with additives to lubricants especially for crank-case use for internal combustion en~ines, which provide a reduction o friction of ~he operating engine.
In order to conserve energy, automobiles are now being engineered to give improved gasoline mileage com-pared ~o those in recent years. This effort is of greaturgency in the United States in view of regulations `-which compel auto manufacturers to achieve prescribed gasoline mileage. These regulations are to conserve crude oil, In an effort to achieve the required mileage, new cars are being down-sized and made m~lch lighter. However, there are limits in this approach beyond which ~he cars will not accommodate a typical family.
Another way to improve ~uel mileage is to reduce engine fric~ion. The present invention is concerned with this latter approach.
The present invention utilizes the finding that a material which is an oil soluble, C12_36 aliphatic hydrocar-byl succinimide or succinamide provides a friction reducing effect where it is incorporated in lubricating oil. Prefer-ably, the aliphatic hydrocarbon group is derived from alinear ~-olefin which has been isomerized to form a mixture of internal olefins. The additive can also be used in the engine fuel.
A preferred embodiment of the invention is a lubri-cating oil composition containing a friction-reducing amount of an additive selected from the group consisting of oil soluble aliphatic hydrocarbon-substituted succinimide and succinamide and mixtures thereof wherein said hydrocarbon substituent contains about 12 to 36 carbon~atoms.
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The aliphatic substituent on the succinic group can be any aliphatic hydrocarbon group containing about 12 to 36 carbon atoms including alkyl, alkenyl and polyunsaturated hydrocarbon groups~ Examples of the above additives include:
n-dodecynyl succinimide l-methyltridecyl succinimide

2-ethyltetradecyl succinimide n-hexadecenyl succinimide _-octadecyl succinimide _-octadecenyl succinimide l-methyleicosyl succinimide _-docosenyl succinimide 4-ethyltriacontyl succinimide n-hexadecenyl succinimide n-dodecenyl succinamide 2-ethyltetradecyl succinamide n-octadecyl succinamidc -n-octadecenyl succinamide.
In a pre~erred embodiment the aliphatic hydrocarbon group 1s bonded to the succinic group at a secondary carbon atom. These compounds have the formula:
/0 ,0 Z - CH - C or Z CH C / NH2 ~H2_ C~ IH C~ NH

or H2N-[-C- CHZ- CH2 - C-NH~ -H
wherein n is a small integer from 2 to about 4 and Z is the group:
Rl \ CH-wherein Rl and R2 are independently selected from the group consisting of branched and straight chain hydrocarbon groups ~13~4~

containing 1 to about 34 carbon atoms such that the total nurnber of carbon atoms in Rl and R2 is about 11 to 35.
Examples of these additives are:
l-ethyltetradecyl succinimide l-methylpentadecenyl succinimide 1,2-dimethyl octadecenyl succinamide l-methyl-3-ethyl dodecenyl succinimide l-decyl-2-methyl dotriacontyl succinimide.
~n a highly pre~erred embodiment R~ and R2 are s~raight chain aliphatic hydrocarbon groups~ These addi-tives have improved solubility in lubricating oil.
Examples of these additives are:
l-methylpentadecyl succinimide l-propyltridecenyl succinimide l-pentyltridecenyl succinimide 1 tridecylpentadecenyl succinimide l-tetradecy~eicosenyl succinimide.
The above highly preferred additives are pre~erably made from linear ~-olefins containing about 12 ~o 36 carbon atoms by isomerizing the ~-ole~ins to ~orm a mixture o~ in-ternal ole~ins and reacting this mixture of internal olefins with maleic acid, anhydride or ester forming an intermediate and reactin~ the intermediate with ammonia to form arnide, imide, or mixtures thereof.
Additives made from isomerized linear ~-olefins have greatly improved oil solubility compared with additives made with linear ~-olefins.
Isomerization of the linear ~-olefin can be carried out using conventional methods. One suitable method is to - 30 heat the linear ~-olefin with an acidic catalyst. Especially useful acid catalysts are the sulfonated styrene-divinylben-zene copolymers. Such catalysts are comrnercially available and are conventionally used as cation exchange resins. In the present method they are used in their acid form. Typi-cal resins are Amberlyst 15j XN-1005 and XN-1010 (registered trademarks) available from Rohm and Haas Company. Use of ~ ., `

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such resins ~or isomerizing linear ~-olefins is described in U. S. 4,108,889~
The method by which the present additives are made are illustrated by the ~ollowing examples;
S Example 1 In a reaction vessel was placed 185 grams of octa-decenyl succinic anhydride. This was melted by heating to 60 C. and ~H3 was injected. An exothermic reaction pro-ceeded raising the temperature to 760 C. After the reac-~ion ceased, the product was heated to 180 C. under about737 mm (29 in.) Hg vacuum to remove volatiles. The product was octadecenyl succinimide.
Example 2 In a reaction vessel was placed 1000 grams of linear ~-octadecene. To this was added 187 grams ~mberlyst 15 (S percent moisture). The mixture was stirred under nitrogen and heated at 120 C. or 3 hours. The isomeriz~d product contained 3.6 weight percent olefin dimer and the balance wa-s internal C 1.8 olein. The product was separated from the resin.
In a second reaction vessel was placed 504 grams o the above isomerized Cl 8 olein and 300 ml heptane. The heptane was distiLled out under vacuum to remove water.
Then 2.4 grams of tri-(3,5-di-tert-butyl-4-hydroxybenzyl)-mesitylene stabilizer was added. The mixture was heatedunder nitrogen to 225 C. Then 160 grams o~ molten maleic anhydride was slowly added over a 2.5-hour period. The mixture was stirred at 225 C. for two more hours and then unreacted maleic anhydride was distilled out by pulling 3Q vacuum to 762 mm (30 in.) Hg while holding the reaction mixture at 200 C. The product was principally secondary Cl 8 alkylene succinic anhydride.
In a separate reaction vessel was placed 532.5 grams o the above isomerized octadecenyl succinic anhydride.
This was heated under nitrogen to 165 C. and then ammonia was injected causing the temperature to rise to 180 C.

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Ammonia injection was continued until exotherm stopped.
The mixture was heated at 170 C. under vac~lum to remove water yielding isomeriæed octadecenyl succinimide.
Example 3 In a reaction vessel was placed 1005 grams of linear ~-eicosene and 187 grams of Amberlyst 15 (5 percent moisture). ~he mixture was heated under nitrogen a~ 110 to 125 C~ for 6 hours. The product was internally un-saturated eicosene containing 3.3 percent eicosene dimer.
lQ In a separate reaction vessel was placed 560 grams of the above isomerized eicosene and 200 ml heptane. The heptane was distilled out to dry the eicosene. At 140 C.,

3.1 grams o tri-(3,5-di-tert-butyl-4-hydroxybenzyl)mesi-tylene stabilizer was added and the mixture hea~ed -to 210 lS C. Over a 2.5-hour period, 156.8 grams of maleic anhydride was added at about 225 C. Following this,unreacted maleic anhydride was distilled out under vacuum at 210 C. leaving isomerized eicosenyl succinic anhydride.
In another reaction vessel was placed 570 grams o the above isomerized eicosenyl succinic anhydride. This was heated to 160 C. and ammonia injection started. The temperature rose to 175 C. Ammonia injection was continued at 175 C. until the temperature dropped. Then 762 mm (30 in.) Hg vacuum was slowly applied to distill out water and ammonia. Additional ammonia was injected to be sure no anhydride remained. There was no further reaction so this ammonia was stripped out at 762 mm (30 in.) Hg vacuum at 170 C. yielding isomerized eicosenyl succinimide.
Example 4 In a reaction vessel was placed 1100 grams of linear Cl6-Cla ~-olefin mixture. The olefin mixture was isomerized following the procedure in Example 3.
In a separate vessel was placed 485 grams (2 moles) of the above isomerized olefin~ This was heated at 100 C.
under 30 inches Hg vacuum to remove water. To it was then :.

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added 2.4 grams tri-(3,5-di-tert-butyl-4-hydroxybenzyl)-mesitylene. The mixture was heated under nitrogen to 225 C. and then 15~ grams of molten maleic anhydride was added over a 3-hour period. The mixture was stirred 30 minutes 5 at 225 C. and an additional 50 grams of maleic anhydride was added. This mixture was stirred 30 minutes at 225 C.
following which unreacted maleic anhydride was distilled out at 200 C. under 762 mm (30 in.) Hg vacuum.
In a separate reaction vessel was placed 598 grams 10 o~ the above isomerized C~ 6-CI 8 alkenyl succinic anhydride.
Ammonia injection was started at 140 C. raising the tem-perature to 145 C. Ammonia injection was continued at 130 C. until no further ammonia was adsorbed. The mix-ture was then heated to 1~0 C. to distill out water and 15 ammonia yielding isomerized Cl 6 -C l~ alkenyl succinimide.
The additives are added to the lubricating oil in an amount which reduces the friction of the engine opera-ting with the oil in the crankcase. A useful concentration is about 0.05 to 3 weight percent. A more preferred range 20 is about 0.1 to 1.0 weight percent.
From the above it can be seen that the present invention provides an improved crankcase lubricating oil.
Accordingly, an embodiment of the invention is an improved motor oll composition formulated for use as a crankcase 25 lubricant in an internal combustion engine wherein the improvement comprises including in the crankcase oil an amount sufficient to reduce fuel consumption of the engine of the friction-reducing additive herein described.
In a highly preferred embodiment such improved motor oil also contains an ashless dispersant and an alkaline earth metal salt of a petroleum sulfonic acid or an alkaryl sulfonic acid (e.g.j alkylbenzene sulfonic :
acid).
The additives can be used in mineral oil or in synthetic oils of viscosity suitable for use in the crank-case of an internal combustion engine. Cran~case lubricating oils have a viscosity up to about 80 SUS at 100 C. (210 F.).
Mineral oils include those of suitable viscosity refined from crude oil from all sources including Gulfcoast, midcontinent, Pennsylvania, Californial Alaska and the li~e.
Various standard refinery operations can be used in proces-sing the mineral oil.
Synthetic oil includes both hydrocarbon synthetic oil and synthetic esters. Useful synthetic hydrocarbon oils including liquid polymers of ~-olefins having the proper viscosity. Especially useful are the hydrogenated liquid oligomers of C6 - I 2 ~-olefins such as ~-decene trimer.
Likewise, alkylbenzenes of proper viscosity can be used, such as didodecylbenzene.
Useful synthetic esters include the esters of both monocarboxylic acid and polycarboxylic acid as well as monohydroxy alkanols and polyols. Typical examples are didocecyl adipate, trimethylol propane tripelargonate, pentaerythritol tetracaproate, di(2-ethylhexyl)adipate, dilauryl sebacate and ~he like. Complex esters prepared from mixtures o~ mono- and dicarboxylic acid and mono-and polyhydro~yl alkanols can also be used.
Blends of mineral oil with synthetic oil are particularly useful. For example, blends of 5 to 25 weight percent hydrogenated a-decene trimer with 75 to 95 weight percent 150 SUS 38 C. (100 F.) mineral oil results in an excellent lubricant. Likewise, blends of about 5 to 25 weight percent di(2-ethylhexyl)adipate with mineral oil of proper viscosity results in a superior lubricating oil.
Also hlends of synthetic hydrocarbon oil with synthetic esters can be used. Blends of mineral oil with synthetic oil are especially useful when preparing low viscosity oil (e.g., SAE 5W 20) since they permit these low viscosities without contributing excessive volatility.
The more preferred lubricating oil compositions include zinc dihydrocarbyldithiophosphate (ZDDP) in ~L3g~0 , combination with the present additives. Both zinc dialkyl-dithiophosphates and zinc dialkaryldithiophosphates as well as mixed alkyl-aryl dithiophosphates can be used. Examples of alkyl-type ZDDP are those in which the hydrocarbyl groups are a mixture of isobutyl and isoamyl alkyl groups. Zinc di-(nonylphenyl)-dithiophosphate is an example of an aryl-type ZDDP Good results are achieved using sufficient zinc dihydrocar~yldithiophosphate to provide about 0.01 to 0.
weight percent zinc. A preferred concentration supplies about 0.05 to 0.3 weight percent zinc.
Another additi~e used in the oil compositions are the alkaline earth metal petroleum sulfonate or alkaline earth metal alkaryl sulfonates. Examples of these are calcium petroleum sulfonates, magnesium petroleum sulfonates, barium alkaryl sulfonates, calcium alkaryl sulfonates or magnesium alkaryl sulfonates. Both the neutral and the overbased sul~onates having base numbers tlp -to a~out: 400 can be beneficially used. These are used in an amo~mt to provide about 0.05 to 1~5 weight percent alkaline earth ~etal and more pre:Eerably about 0.1 ~o 1.0 weigh~ percent.
Visc.osity index improvers can be included such as the polyalkylmethacrylate type or the ethylene-propylene copolymer type. Likewise, styrene-diene VI improvers can be used. Alkaline earth metal salts of phosphosulfurized polyisobutylene are useful. Preferred crankcase oils also contain an ashIess dispersant such as the polyolefin succinamides and succinimides of polyethylene polyamines such as tetraethylenepentamine. The polyolefin succinic substituent is preferably a polyisobutene group having a molecular weight of from about 800 to 5,000. Such ashless dispersants are more fully described in U. S. 3,172,892 and U. S. 3,219,666, Other useful ashless dispersants include the Mannich condensation products of polyolefin-substituted phenols, formaldehyde and polyethylene polyamine. Prefer-ably, the polyclefin phenol is a polyisobutylene-substituted -~,t ~, -, :

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p~lenol in which the polyisobutylene group has a molecular weight of from about 800 to 5,000. The preferred poly-ethylene polyamine is tetraethylene pentamine. Such Man-nich ashless dispersants are more fully descirbed in U. S.
3,368~972; U. S. 3,413,347; U. S. 3,442~808; U. S~
3,448,047; U. S. 3,539,633; U. S. 3,591;598; U. S.
3,600,372; U. S. 3>634,515; U. S. 3,697,574; U. S.
3,703,536; U. S. 3,704,308; U. S. 3 7 725,480; U. S.
3,726,8~2; U. S. 3,736,357; U. S. 3,751,365; U. S.
3,756,~53; U. S. 3,793,202; U. S. 3,798,165; U. S.
3,798,247 and U. S. 3~803,039.
The friction-reducing additives of this invention are also useful in fuel compositions. Fuel injected or inducted into a combustion chamber wets the walls of the ].5 cylinder. Fuels containing a small amolmt of the present additive reduce the fricti.on due to t'he piston ri.ngs sliding against the cylinder wall.
The additives can be used in both diesel fuel and gasoline used to operate internal combustion engines.
Fuels containing about 0.001 to 0.25 weight percent of the friction-reducing additives can be used.
Fuels used with the invention can contain any of the additives conventionally added to such fuels. In the case of gasoline it can include dyes, antioxidants, deter-gents, antiknocks (e. g., tetraethyllead, methylcyclopenta-dienylmanganese tricarbonyl, rare earth metal chelates, methyl' t'ert-butylether and the like). In the case of diesel fuels the compositions can include pour point de-pressants, detergents, ignition improvers (e.g., hexyl-nitrate) and the like.
Tests were conducted using a 1977 U. S. production.automobile. These were shortened versions of the Federal City EPA cycle. This is referred to as the "Hot 505"
cycle. It consists of the first 3.6 miles (5.8 km~ of the Federal EPA City cycle started with a warmed-up engine in-stead of a cold engine. The car with a fully formulated . `'. ,. '' ' . . .
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SE grade oil in its crankcase is operated on a chassis dynamometer for about one hour at about 88 km/hr. (55 mph) to stabilize oil temperature. It is then run through Eour consecutive "Hot 5a5" cycles measuring fuel economy of the base oil. Results of the four cycles are averaged. Then one-half of the base oil is drained rom the crankcase and replaced with the same base oi~ containing a double dose o~ the test additive, The car is then run at about 88 km/hr.
(55 mph) ~or about one hour to again stabilize temper~ture.
A second series of four consecutive "Hot 505" cycles is run to measure initial fuel economy of the base oil containing the test additive. The car is then run about 805 km ~500 miles) at constant speed of about 88 km/hr. (55 mph). Then a third series of four consecutive "Hot 505" cycles are run to measure ~uel economy aEter about 805 km (500 miles) operation on the oil containing the test add:Ltive. The crankcase is then drained hot and filled wikh :Elushing oil which is run for a short time and then drained. The crank-case is then filled with the base oil which i.s run for a short time and then drained. The crankcase is then filled a second time with a base oil. This is run about one hour at about 8~ km/hr. (55 mph~ to a stable temperature. Then a fourth series of four consecutive 'IHot 505`' cycles are run measuring fuel economy. This gives a second base line thus bracketing the test carried out with the friction additive between two base line tests.
The following table shows the percent improvement in fuel economy over the base oil obtained using 1 weight percent of the friction-reducing additive.

Additive Percent Gain in Fuel Ecomony Initial About 805 km (500 miles) Average _ Isomerized Cl 6-18 alkenyl succinimide 1.6 0.9 1.3 The reduction in fuel consumption though small is significant.

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Claims

Canada THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A lubricating oil composition containing a friction-reducing amount of an additive selected from the group consisting of oil soluble aliphatic hydrocarbon-substituted succinimide and succinamide and mixtures thereof wherein said hydrocarbon substituent contains about 12 to 36 carbon atoms.

2. A lubricating oil composition of Claim 1 wherein said additive is an alkyl or alkenyl succinimide.

3. A lubricating oil composition of Claim 2 wherein said additive is tetradecenyl succinimide.

4. A lubricating oil composition of Claim 2 wherein said additive is hexadecenyl succinimide.

5. A lubricating oil composition of Claim 2 wherein said additive is octadecenyl succinimide.

6. A lubricating oil composition of Claim 2 wherein said additive is eicosenyl succinimide.

7. A lubricating oil composition of Claim 1 wherein said additive has the structure:

or or wherein Z is the group wherein n is an integer from 2 to about 4, R1 and R2 are independently selected from the group consisting of branch and straight chain hydrocarbon groups containing 1 to about 34 carbon atoms such that the total number of carbon atoms in R and R2 is about 11 to 35.

8. A lubricating oil composition of Claim 7 wherein R1 and R2 are straight chain aliphatic hydrocarbon groups.

9. A lubricating oil composition of Claim 7 wherein said additive is made by the process comprising (1) isomerizing the olefinic double bond of a linear .alpha.-olefin containing about 12 to 36 carbon atoms to obtain a mixture of internal olefins, (2) reacting said mixture of internal olefins with maleic acid, anhydride or ester to obtain an intermediate hydrocarbon-substituted succinic acid, anhy-dride or ester and reacting said intermediate with ammonia to form an amide, imide or mixture thereof.

10. A lubricating oil composition of Claim 9 wherein said .alpha.-olefin consists mainly of linear .alpha.-tetradecene.

11. A lubricating oil composition of Claim 9 wherein said .alpha.-olefin consists mainly of linear .alpha.-hexadecene.

12. A lubricating oil composition of Claim 9 wherein said .alpha.-olefin consists mainly of linear .alpha.-octadecene.

13. A lubricating oil composition of Claim 9 wherein said .alpha.-olefin consists mainly of linear .alpha.-eicosene.

14. An oil-soluble friction-reducing additive having the structure:

or or an intermolecular imide having the structure:

wherein n is an integer from 2 to about 4 and wherein Z
has the structure:

wherein R1 and R2 are independently selected from the group consisting of straight and branched chain hydrocarbon groups containing 1 to about 34 carbon atoms such that the total number of carbon atoms in R1 and R2 is about 11 to 35.

15. An oil-soluble friction-reducing additive of Claim 14 wherein R1 and R2 are straight chain aliphatic hydrocarbon groups.

16. An oil-soluble additive of Claim 15 wherein the total number of carbon atoms in R1 and R2 is about 15 to 21.

17. An oil-soluble additive of Claim 14 made by the process comprising (a) isomerizing the olefinic double bond of a linear .alpha.-olefin or mixture thereof containing about 12 to 36 carbon atoms to obtain a mixture of internal olefins, (b) reacting said mixture of internal olefins with maleic acid, anhydride or ester to obtain an intermediate hydrocarbon-substituted succinic acid, anhydride or ester and (c) reacting said intermediate with ammonia to form an amide, imide or mixture thereof.

18. A liquid hydrocarbon fuel suitable for use in an internal combustion engine containing a minor friction-reducing amount of an additive selected from the group con-sisting of fuel soluble aliphatic hydrocarbon-substituted:
succinimide and succinamide and mixtures thereof wherein said hydrocarbon substituent contains about 12 to 36 carbon atoms.

19. In a lubricating oil formulated for use in the crankcase of an internal combustion engine, the improve-ment comprising including in said lubricating oil an amount sufficient to reduce fuel consumption of said engine of an additive selected from the group consisting of oil-soluble aliphatic hydrocarbon-substituted succini-mides and succinamides and mixtures thereof wherein said hydrocarbon substituent contains about 12 to 36 carbon atoms.

20. The improved lubricating oil of Claim 19 wherein said additive is selected from the group consisting of hexadecenyl, octadecenyl and eicosenyl succinimides and succinamides and mixtures thereof.

21. The improved lubricating oil of Claim 20 wherein said additive is an eicosenyl succinimide.