US3182024A - Polyaminopyrrolidines in lubricating oils - Google Patents

Description

United States Patent This invention pertains to lubricating oil compositions containing metal-free detergents having acid-neutralizing characteristics.

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 conditions for a large percentage of todays automobiles, the internal combustion engines do not reach the most efiicient 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 efiectiveness 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 dis advantage of forming ash deposits in the engine. These ash deposits lower engine performance by fouling spark plugs and valves, and contribute to preignition.

It is a particular object of this invention to provide lubricating oil compositions which are compounded with metal-free detergents having acid-neutralizing characteristics.

Therefore, in accordance with this invention, it has been discovered that lubricating oil compositions particularly useful for heavy duty service are obtained by incorporating certain N-polyaminopyrrolidines in oils of lubricating viscosity.

The polyarninopyrrolidines described herein are effective not only as detergents in lubricating oil compositions, but they also effectively neutralize acids which are formed. Thus, by the use of lubricating oil compositions containing the particular pyrrolidiues described herein, diesel and gasoline engine parts remain remarkably free of deposits and varnish, even under severe operating conditions.

These polyaminopyrrolidines are 1-aminoalkyl-3-alkenylpyrrolidines wherein the alkenyl radical has at least carbon atoms, more preferably to 200 carbon atoms, and the alkyl radical has from 2 to 6 carbon atoms. These also include the 1-polyaminoalkyl-3-alkenyl pyrrolidines.

The polyaminopyrrolidines can be represented by the formula:

wherein R is an alkenyl radical having from 30 to about 200 carbon atoms, R is a divalent alkylene radical having from 2 to 6 carbon atoms, and x is a number from dissolved in 9 liters of ethyl ether.

0 to 8. The R radicals may be derived from polyalkylene polyamine reactants.

These pyr-rolidines can be obtained by first preparing the pyrrolidinedione by the reaction of an olefinic hydrocarbon With maleic anhydride. The resulting alkenyl succinic anhydride is then reacted with the desired polyamine to form the pyrrolidinedione, which then can be reduced (hydrogenated) to form the corresponding pyrrolidine.

Examples of polyalkylene polyamine reactants include diethylene triamine, dipropylene triamine, tetraethylene pentamine, pentaethylene hexamine, nonaethylenenedecamine, dihexamethylene triamine, etc.

In addition to polyalkylene polyamine reactants, other amines can be used, such as, alkylaminoalkylene amines of the formula:

R2 lEhN-Rl-N wherein R is an alkylene radical, and R and R are alkyl radicals having from 1 to 4 carbon times. The sum of carbon atoms in R R and R is preferably from 3 to 10.

The polyaminopyrrolidines can be prepared by reducing the corresponding alkenyl pyrrolidinedione.

Lubricating oils which can be used as base oils include a wide variety of lubricating oils, such as naphthenic base, paraffin base, and mixed base lubricating oils, other hydrocarbon lubricants, e.g., lubricating oils derived from coal products, and synthetic oils, e.g., alkylone polymers (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, fumaric acid, maleic acid, etc., with alcohols such as butyl alcohol, hexyl alcohol, Z-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 Z-ethyl hexyl benzene); polyphenyls (e.g. bi phenyls and terphenyls), alkyl biphenyl others, 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(rnethy1- phenyl) siloxane, etc.

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

These pyrrolidines can be used in oils of lubricating viscosity in amounts of 0.1% to 39% by Weight, preferably 0.25% to 5%, by weight.

The following examples illustrate the preparation of the pyrrolidines described herein.

EXAMPLE I. PREPARATION OF 1-(TRIETHYL- ENETETRAMINOETHYL) -3 OLYTSOBUTENYL PYRROLIDINE Forty-two grams of lithium aluminum hydride was Twelve hundred grams of approximately 45% petroleum oil solution of N-tetraethylene pentamine polyisobutenylpyrrolidine-dione, wherein the polyisobutenyl radical had a molecular weight of about 850 (the oil solution having a nitrogen content of 1.78%), was added to the ether solution over a period of 3 hours so as to maintain a gentle reflux. This solution was stirred while refluxing for an additional 6 hours. Thirty milliliters of water was slowly added over a period of 3 hours to decompose unreacted lithium aluminum hydride followed by the addition of 470 ml. of water. The mixture was allowed to settle and the ether layer was decanted and filtered. The ether solution was washed with aqueous sodium carbonate solution, centrifuged, dried over anhydrous sodium carbonate, filtered, and freed of solvent under vacuum.

The final product which had a nitrogen content of 1.50% of which 1.13% was basic nitrogen, was essentially free of lithium and aluminum. Infrared analysis showed that the carbonyl groups present in the original pyrrolidinedione were no longer present.

EXAMPLE II.PREPARATION OF l-(TRIETHYL- ENETETRAMINOETHYL) -3 POLYISOBUTENYL PYRROLIDINE A six hundred grams of approximately 45% petroleum oil solution of N-tetraethylene pentamine polyisobutenylpyrrolidinedione, wherein the polyisobutenyl radical had a molecular weight of about 850, was blended with 800 ml. of ethyl ether. This blend was slowly added to a solution of 30 g. of lithium aluminum hydride in 2500 ml. of ethyl ether. The mixture was stirred under reflux for 12 hours after which 300 ml. of water was slowly added. The ether solution was washed with aqueous sodium hydroxide and centrifuged. The ether was removed by heating at 150 C. at an absolute pressure of 2 mm. of mercury. Analysis showed a nitrogen content of 1.87% and an absence of carbonyl groups.

EXAMPLE III.PREPARATION OF I-(B-DIMETH- YLAMINOPROPYL)-3 POLYISOBUTENYLPYR- ROLIDINE Seven hundred grams of a 45% petroleum oil solution of N-dimethylaminopropyl polyisobutenyl pyrrolidinedione, the oil solution having a nitrogen content of 1.04%, was blended with 500 ml. of ethyl ether. This solution was slowly added to a solution consisting of 20 g. of lithium aluminum hydride in 750 m1. of ethyl ether. This solution was heated at reflux temperature overnight with agitation. Water was added, the solution filtered, dried over sodium sulfate, and the solvent removed by distillation to a temperature of 110 C. under vacuum. Analysis indicated a nitrogen content of 0.96%, and the absence of carbonyl groups.

EXAMPLE IV.PREPARATION OF 1-(2-AMINO- ETHY L) -3-POLYISOBUTENYLPYRROLIDINE Two hundred grams of a 34.9% petroleum oil solution of polyisobutenylsuccinic anhydride having a molecular weight of 1030 was blended with 300 ml. of xylene. This blend was dripped into 203 g. of warm, ethylenediamine with agitation. The mixture was distilled at 1 atm. to a pot temperature of 150 C. after which a vacuum was applied to the vessel and the temperature maintained at 170 C. for 2 hours.

On analysis, it was found that the nitrogen content was 0.90%, with the basic nitrogen content being 0.34%. This analysis showed that the product was an oil solution containing 34.5% active pyrrolidinedione material having a molecular weight of 1072.

The resulting pyrrolidinedione was reduced by slowly adding a solution consisting of 100 g. of the pyrrolidinedione dissolved in 100 ml. of dry ether to a stirred slurry of 3.5 g. of lithium aluminum hydride in 150 ml. of ether. This mixture was refluxed gently for 5 hours, treated with water, filtered, dried over potassium carbonate and heated to remove the solvent. On analysis, it was found that the total nitrogen content was 0.82%. Infrared analysis showed that no carbonyl groups were present.

EXAMPLE V.-PREPARATION OF l-(6-AMINO- HEXYL) -3 -POLYISOBUTENYLPYRROLIDINE The pyrrolidinedione was first prepared by reacting 430 g. of an oil solution (35%) of polyisobutenyl succinic i anhydride (1030 mol wt.) with 350 g. of 1,6-hexanediamine. The solution was heated to 170 C. at an absolute pressure of 1 mm. of mercury to remove the excess diamine. The pyrrolidinedione was reduced by diluting with ether and dripping the ether solution into a dispersion of 15 g. of lithium aluminum hydride in 500 ml. of ether, followed by treatment in the manner set forth hereinabove.

On analysis, the product was found to have a total nitrogen content of 0.88%.

Table I hereinbelow presents engine data obtained with lubricating oil compositions containing 7.3% of the oil solution of the pyrrolidine of Example II hereinabove.

The test was a Caterpillar l-H engine test run for the period of 120 hours.

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; a 0 evaluation being a clean groove; and a number of being a groove full of deposits.

The base oil was a California SAE 30 base oil.

1 These test results were obtained in a Caterpillar L-l test under the MIL-k210i conditions. Thus, under the more severe supplement-1 conditions, the GD No. would be considerably higher.

In addition to the pyrrolidines described hereinabove, the lubricating oil compositions may contain other detergents, rust inhibitors, corrosion inhibitors, pour point depressants, oiliness agents, oxidation inhibitors, etc.

' We claim: 1. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity, and from 0.1% to 30% by weight, of l-aminoalkyl-B-alkenyl pyrrolidine wherein the alkenyl radical has from 30 to 200 carbon atoms and the alkyl radical has from 2 to 6 carbon atoms.

2. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity, and from 0.25% to 5% by weight, of 1-aminoalkyl-3-alkeny1 pyrrolidine wherein the alkenyl radical has from 30 to 200 carbon atoms and the alkyl radical has from 2 to 6 carbon atoms.

3. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity, and from 0.1% to 30% by weight of an N-aminoalkyl-pyrrolidine of the formula wherein R is an alkenyl radical having from 30 to 200 carbon atoms, R is a divalent alkylene radical having from 2 to 4 carbon atoms, and x is a number from 0 to 6.

4. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity, and from 0.1% to 30% by weight of an N-aminoalkyl-pyrrolidine of the formula R-CHCH3 N-RNR -NH Hg-CH g x wherein R is an alkenyl radical having from 30 to 200 carbon atoms, R is a divalent alkylene radical having 2 carbon atoms, and x is a number from to 6.

5. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity, and from 0.1% to 30% by weight of an N-aminoalkyl-pyrrolidine of the formula R-oH oH,

/N-R-LNR-\NHQ UH -CH, 4 wherein R is an alkenyl radical having from 30 to 200 carbon atoms, and R is a divalent radical having 2 carbon atoms.

6. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity, and from 0.25% to 5% by weight of an N-arninoalkyl-pyrrolidine of the formula wherein R is an alkenyl radical having from 30 to 200 carbon atoms, and R is a divalent radical having 2 carbon atoms.

7. A lubricating oil composition comprising a major proportion of an oil of lubricating viscosity and from 0.1% to 30% by weight of 1-(triethylenetetraminoethyl)- wherein R is an alkenyl radical having from to 200 carbon atoms, R is a divalent alkylene radical having from 2 to 4 carbon atoms and x is a number from O to 6.

10. As a novel compound, 1-(3-dimethylaminopropyl)- 3-polyisobutenylpyrrolidine, wherein said polyisobutenyl radical contains from 30 to 200 carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS 1/62 Anderson et al. 25251.5 3/63 Aspergren 260313 DANIEL E. WYMAN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,182,024 May 4, 1965 Frank A. Stuart 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.

Column 2, line 22, for "carbon times" read carbon atoms column 4, lines 70 to 75, for that portion of the formula reading column 5, lines 7 to 10, for that portion of the formula reading N-R read N-R Signed and sealed this 16th day of November 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims (1)

1. A LUBRICATING OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF AN OIL OF LUBRICATING VISCOSITY, AND FROM 0.1% TO 30% BY WEIGHT, OF 1-AMINOALKYL-3-ALKENYL PYRROLIDINE WHEREIN THE ALKENYL RADICAL HAS FROM 30 TO 200 CARBON ATOMS AND THE ALKYL RADICAL HAS FROM 2 TO 6 CARBON ATOMS.