US 3024195 A
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United State 3,024,195 Patented Mar. 6, 1932 3,024,195 LUBRICATING OIL COMPGSKTHONS F ALKYL- PIPERAZINE ALKENYL SUCCINIMIDES Alan Y. Drummond, Richmond, Robert G. Anderson, Novato, and Frank A. Stuart, Orinda, Calif, assignors to California Research Corporation, San Francisco, Calif., a corporation of Delaware N0 Drawing. Filed Aug. 24, 1959, er. No. 835,391 9 Claims. (Cl. 252-51.5)
This invention pertains to lubricating oil compositions having incorporated therein metal-free detergents. These particular metal-free detergents are N-substituted alkenyl succinimides.
Alkenyl succinic anhydrides and numerous derivatives thereof are well known in the art. For example, alkenyl succinic anhydrides in which the alkenyl radical contains from to 20 carbon atoms are taught as corrosion inhibitors in lubricating oil compositions. Also, products obtained by reacting such alkenyl succinic acid anhydrides with non-cyclic monamines are taught as ferrous corrosion inhibitors for lubricating oil compositions.
However, the above known alkenyl succinimides are not useful as detergents in lubricating oil compositions. In contrast thereto, the N-substituted polyamine alkenyl succinimides which are described herein are new compounds which are useful as detergents in lubricating oil compositions.
Present day internal combustion engines operate at high speeds and high compression ratios. When used in the so-called city stop-and-go driving, which includes the greater part of the driving condition for a large percentage of todays automobiles, the internal combustion engines do not reach the most efficient operating temperature. Under city driving conditions, large amounts of partial oxidation products are formed, and reach the crankcase of the engine by blowing past the piston rings. Most of these partial oxidation products are oil insoluble, tending to form deposits on the various operating parts of the engine, such as the pistons, piston rings, etc. For the purpose of preventing the deposition of these products on the various engine parts, it is necessary to incorporate detergents in the lubricating oil compositions, thus keeping these polymeric products highly dispersed in a condition unfavorable for deposition on metals.
For the most part, the various detergents which are added to crankcase oils to reduce this formation of sludges and varnishes are metal organic compounds, particularly those compounds wherein the metal is linked to an organic group through an oxygen atom. Although these metal-containing organic compounds have some effectiveness as detergents for dispersing the precursors of deposits within the oil itself rather than permitting them to form added deposits on the engine parts, they have the disadvantage of forming ash deposits in the engine. These ash deposits lower engine performance 2 by fouling spark plugs and valves, and contributing to preignition.
It is a particular object of this invention to provide lubricating oil compositions which are compounded with a metal-free detergent.
Therefore, in accordance with this invention, it has been discovered that lubricating oil compositions particularly useful for heavy duty service are obtained by incorporating N-alkylpiperazine monoalkenyl succinimides in oils of lubricating viscosity.
By the use of lubricating oil compositions containing the N-substituted alkenyl succinimides described herein, diesel and gasoline engine parts remain remarkably free of deposits and varnish, even under severe operating conditions.
The N-alkylpiperazine monoalkenyl succinimides are new compounds of the formula:
wherein R is a hydrocarbon radical having a molecular weight from about 400 to about 3000; that is, R is a hydrocarbon radical containing about 30 to about 200 carbon atoms; R is a hydrocarbon radical containing from 1 to 3 carbon atoms; and R" is hydrogen or a hydrocarbon radical containing from 1 to 3 carbon atoms.
These N-substituted alkenyl succinimides can be prepared by reacting maleic anhydride with an olefinic hydrocarbon followed by reacting the resulting alkenyl succinic anhydride with an N-(p-aminoalkyl) piperazine. Such N-(B-aminoalkyl) piperazines are exemplified by N-methyl-N-(fi-aminoethyl) piperazine, N-isopropyl-N'- (fiaminoethyl) piperazine, N-(B-aminoisopropyl) piperazine, etc.
The R radical of the above formula, that is, the alkenyl radical, is derived from an olefin containing from 2 to 5 carbon atoms. Thus, the alkenyl radical is obtained by polymerizing an olefin containing from 2 to 5 carbon atoms to form a hydrocarbon having a molecular weight ranging from about 400 to about 3000, more preferably, 900 to 1200. Such olefins are exemplified by ethylene, propylene, l-butene, Z-butene, isobutene, and mixtures thereof. Since the methods of polymerizing the olefins to form polymers thereof is immaterial in the formation of the new compound described herein, any of the numerous processes available can be used therefor.
The preparation of N-substituted monoalkenyl succinimides derived from amine derivatives of piperazine can be described generally by the following equations, using a polymer of isobutene as an example of the alkenyl radical; and N-(fi-aminoethyl) piperazine as an example of an N-(aminoalkyl) piperazine:
wherein n has a value of about 7 to about 50.
The above reaction between a polyolefin and maleic anhydride is an uncatalyzed addition reaction which should not be confused with a copolymerization reaction such as that obtained with a vinyl monomer and maleic anhydride. While the general reaction of an olefin and maleic anhydride is well known for olefins of low molecular weight (e.g., olefin-s of 18 carbon atoms), no previous work has been done with maleic anhydride and the high molecular weight olefins as described herein.
The reaction set forth and described by Equation I hereinabove can proceed in a mol ratio of the polyolefin to the maleic anhydride of 1:1 to 1:10, preferably from 1: 1 to 1:5. The reaction temperature can vary from 300 F. to 450 F. Because of the greater yield of products obtained thereby, it is preferred to use the high range of temperatures (e.g., 375 to 450 F.).
In the second step of the reaction as exemplified by Equation II hereinabove, the yield of the imide is extremely high even though the reactants are used in equal molor ratios.
The reaction described by Equation II hereinabove can be made at 220 F. to 500 F., preferably from 300 F. to 400 F. The alkenyl succinic anhydride and the N-alkylaminepiperazines are reacted in about equal molar quantities.
Since the reaction between the polyolefin and maleic anhydride may not go to completion, the resulting alkenylsuccinic anhydride may contain some unreacted polyolefin. As it may not be desirable to separate out this unreacted polyolefin at this stage, the resulting imide formed by reaction of the alkenyl succinic anhydride and the diamine will contain this polyolefin as an impurity which can be a diluent in the formation of lubricating oil compositions. However, if it is so desired, this unreacted polyolefin' can be removed by precipitation, for example, by acetone or methanol from a hydrocarbon solution.
Lubricating oils which can be used as base oils include a wide variety of lubricating oils, such as naphthenic base, paraifin base, and mixed base lubricating oils, other hydrocarbon lubricants, e.g., lubricating oils derived from coal products, and synthetic oils, e.g., alkylene poly- .mers (such as polymers of propylene, butylene, etc., and the mixtures thereof), alkylene oxide-type polymers (e.g., propylene oxide polymers) and derivatives, including alkylene 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, furnaric acid, maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol, 2-ethyl hexyl alcohol, dodecyl alcohol, etc.), liquid esters of acids of phosphorus, alkyl benzenes (e.g., monoalkyl benzene such as dodecyl benzene, tetradecyl benzene, etc., and dialkyl benzenes (e.g., nnonyl 2-ethyl hexyl benzene); polyphenyls (e.g., biphenyls and terphenyls), alkyl biphenyl ethers, polymers of silicon (e.g., tetraethyl silicate, tetrai-sopropyl silicates, tetra-(4-methyl-2-tetraethyl) silicate, hexyl (4-methyl-2-pentoxy) disiloxane, poly(rnethyl) 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, wherever miscible or Wherever made so by the use of mutual solvents.
The above-described alkenyl succinimides of this in vention can be used in oils of lubricating viscosity in amounts of 0.1% to by weight, preferably 0.25% to 5%, by weight.
The preparation of N-alkylpiperazine alkenyl succinimides is illustrated in the following examples.
EXAMPLE I.-PREPAR ATION OF POLYBUTENYL SUCCINIC ANHYDRIDE A mixture of 1000 grams (1 mol) of a polybutene having a molecular Weight of about 1000 and 98 grams (1 mol) of maleic anhydride was heated at 410 F. in a nitrogen atmosphere with agitation for a period of 24 hours. The reaction mixture was cooled to 150 F. and 700 cc. of hexane added; after which the mixture was filtered under vacuum. After vacuum distillation to remove the hexane from the filtrate, the product was maintained at 350 F. atan absolute pressure of 10 mm. Hg for one hour to remove traces of maleic anhydride. The crude polybutenyl succinic anhydride thus prepared had a saponification number of 79.
EXAMPLE lI.-PREPARATION OF N-ETHYLPIPER- AZINE POLYBUTENYL SUCCINIMIDE ANHY- DRIDE A mixture of 18 grams (0.14 mol) of N-(fl-aminoethyl) piperazine and 200 grams (0.127 mol) of the polybutenyl succinic anhydride of Example I hereinabove was blended with agitation in a nitrogen atmosphere. The mixture was heated at 500 F. for one hour, after which the absolute pressure was reduced to about 200 mm. Hg to facilitate the removal of water and unreacted piperazine. The reaction mixture was then allowed to reach room temperature at this reduced pressure. The reaction product contained 2.59% nitrogen (theory=2.67%). Infrared analysis showed that the reaction product was an imide containing a polybutene side chain.
Table I hereinbelow presents data obtained with lubricating oil compositions containing N-alkylpiperazine monoalkenyl succinimides.
The tests were made in a Caterpillar L-1 engine according to MilL-2104 conditions for a period of .120 hours as described in the Coordinating Research Council Handbook, January 1946.
The PD Nos. refer to the piston discoloration rating. After the engine test, the three piston lands are examined visually. To a piston skirt which is completely black is assigned a PD number of 800; to one which is completely clean, a PD number of 0; to those intermediate between completely black and completely clean are assigned PD numbers intermediate in proportion to the extent and degree of darkening.
The GD Nos. refer to the percentage deposits in the piston ring grooves; and 0 evaluation being a clean groove; and a number of being a groove full of deposits.
The base oils were California SAE 30 base oils.
Table I Additive A B C Sueclnimide, weight percent 0. 1.0 1.0 Dithiophosphate;mM./kg 0. 0 0. 0 12 st Results:
GD N o 39 1 0.3 PD N0 800, 800, 800 25, 0, 5 10, 0, 0
Table II hereinbelow presents data obtained in an FL2 test, using a 6-cylinder Chevrolet engine operating at 2500 r.p.m. for a period of 40 hours, which test is fully described in a Coordinating Research Council bulletin titled Research Technique for the Determination of the Elfects of Fuels and Lubricants on the Formation of Deposits During Moderate Temperature Operation (1948).
The piston varnish rating is a visual observation of the amount of varnish on a piston skirt, with 10 being the maximum rating for a perfectly clean piston and a 0 being the rating of a piston fully covered with black varnish. This piston varnish rating correlates with road performance in automobiles.
The base oil was an SAE 30 base oil.
The succinimide and the dithiophosphate were the same as those described for Table I hereinabove.
It is readily seen from the data set forth hereinabove in Tables I and -II that lubricating oil compositions containing the N-alkylpiperazine alkenyl succinimides as described herein are superior as lubricating oil compositions for the lubricating of internal combustion engines.
vIn addition to the dithiophosphate described hereinabove, lubricating oil compositions containing the N-substituted alkenyl succinimides of N-alkylpiperazine of this invention may also contain other detergents, viscosity index improving agents, rust inhibitors, oiliness agents, grease thickening agents, etc.
1. A lubricating oil composition consisting essentially of an oil of lubricating viscosity and from 0.1% to 80%, by Weight, of an N-alkylpiperazine monoalkenyl succinimide of the formula:
wherein R is a hydrocarbon radical having a molecular weight from about 400 to about 3000, and R is a hydrocarbon radical containing from 1 to 3 carbon atoms.
2. A lubricating oil composition consisting essentially of an oil of lubricating viscosity and from 0.1% to by weight, of an N-alkylpiperazine monoalkenyl succinimide of the formula:
wherein R is a hydrocarbon radical having a molecular weight from about 900 to about 1200, and R' is a hydrocarbon radical containing from 1 to 3 carbon atoms.
3. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity and firom 0.25 to 5%, by weight, of an N-alkylpiperazine monoalkenyl succinimide of the formula:
wherein R is a hydrocarbon radical having a molecular weight from about 900 to about 1200, and R is a hydrocarbon radical containing from 1 to 3 carbon atoms, and R" is selected from the group consisting of hydrogen and hydrocarbon radicals containing from 1 to 3 carbon atoms.
4. A lubricating oil composition comprising a major proportion of a petroleum lubricating oil and from 0.25% to 5%, by weight, of an N-substituted monoalkenyl succinimide of the formula:
CHz-CH: CHa/n CHICHQN NH GHQ-T"? CHPCHI wherein n has a value of about 7 to about 5 0.
5. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity and a minor proportion, in an amount sufiicient to impart detergency to said oil, of an N-alkylpiperazine monoalkenyl succinim ide of the formula:
wherein R is a hydrocarbon radical having a molecular weight from about 400 to about 3,000, R is a hydrocarbon radical containing from one to three carbon atoms, and R" is selected from the group consisting of hydrogen and hydrocarbon radicals containing from 1 to 3 carbon atoms.
6. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity and a minor proportion, an amount sufiicient to impart detergency to said oil, of an N-alkylpiperazine monoalkenyl succinimide of the formula:
wherein R is a hydrocarbon radical containing from about 30 to about 200 carbon atoms formed by polymerizing olefins containing from 2 to 5 carbon atoms, and R is a hydrocarbon radical containing from 1 to 3 carbon atoms.
7. A lubricating oil composition consisting essentially of an oil of lubricating viscosity and from about 0.1% to about 80%, by weight, of an N-alkylpiperazine monoalkenyl succinimide of the formula:
wherein R is an aleknyl radical containing from 30 to 200 carbon atoms and which is a polymer of an olefin containing from 2 to 5 carbon atoms, and R is an alkyl radical containing from 1 to 3 carbon atoms.
8. A lubricating oil composition comprising a" major C II;
proportion of an oil of lubricating viscosity and from 0.25% to 5%, by weight, of an N-alkylpiperazine monoalkenyl succinimide of the formula:
wherein n has a value of about 7 to about 50.
References Cited in thefile of this patent UNITED STATES PATENTS 2,490,744 Trigg et al Dec. 6, 1949 2,604,451 Rocchini July 22, 1952 2,638,450 White et a1 May 12, 19 52 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 3,024,195 March a, 1962 Alan Y. Drummond et a1.
It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
Columns 1 and 2, bottom of the page, the front end portion of the reactant and the reaction product of the equations, and the top of column 3, two occurrences, should appear as shown below instead of as in the patent:
H CH3 n column 2, lines 18 to 24, column 5, lines 69 to 75, column 6, lines 8 to 13, lines 21 to 27, lines 49 to 55, lines 67 to 73, column '7, lines 7 to 13, and column 8, lines 4 to 9,
the left-hand portion of the formula, each occurrence, should appear as shown below instead of as in the patent:
IRNEST W. SWIDER lttesting Officer DAVID L. LADD Commissioner of Patents