US3640855A

US3640855A - C-alkyloxy substituted tert.-butyl amine as lubricating oil detergent

Info

Publication number: US3640855A
Application number: US758123A
Authority: US
Inventors: Nicolaas Bakker
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1968-09-06
Filing date: 1968-09-06
Publication date: 1972-02-08
Anticipated expiration: 1989-02-08
Also published as: US3796756A

Abstract

Tert.-butyl amines having an alkyl group of at least 10 carbon atoms bonded through a heteroatom to carbon find use as detergents in lubricating oils.

Description

I Umted States Patent 51 3,640,855 Bakker 1 Feb. 8, 1972 [54] C-ALKYLOXY SUBSTITUTED TERT.- 5 References cited BUTYL AMINE AS LUBRICATING OIL UNITED STATES PATENTS DETERGENT 3,309,316 3/1967 McNinch et a1. ..252/51.5 A [721 Nm'aas Cahf' 3,340,192 9/1967 Henley ..252/s1.5

73 A h I 1 Ss'gnee g zgfg Company San Fran FOREIGN PATENTS OR APPLICATIONS 22] Filed: Sept. 6, 1968 1,138, 2 6/1957 France Appl' 758,123 Primary ExaminerDaniel E. Wyman Assistant Examiner-W. Cannon [52] us. Cl ..252/32.7, 252/46.7, 252/515, A rn y-A L- w, h n and I. Rowland 260/584 51 1m.c1 ..C10m 1/38,C10m l/32,Cl0m 1/20 57 ABSTRACT [58] Field of Search ..252/51.5, 46.4, 32.7 E, 46.7;

260/584 C Tert.-butyl ammes havmg an alkyl group of at least 10 carbon atoms bonded through a heteroatom to carbon find use as detergents in lubricating oils.

5 Claims, No Drawings C-ALKYLOXY SUBSTITUTED TERT.-BUTYL AMINE AS LUBRICATING OIL DETERGENT BACKGROUND OF THE INVENTION l. Field of the Invention An accelerated improvement in performance of lubricating oils has resulted from the addition to the lubricating oils of a I variety of new additives. One of the most important additives has been the ashless lubricating detergent. These detergents which are effective over a wide range of conditions-the high temperatures of the diesel engine to the cyclical and lower temperatures of the automobile internal combustion enginehave provided greatly improved performance in the dispersion in the oil of deposit-forming materials.

Efforts are being continually made to further reduce the deposits. Deposits comprise not only black material, but a light-colored thin film referred to as varnish." This resinous material or lacquer is only difficulty prevented. Since the mechanisms for sludge formation and varnish formation are not the same, ashless detergents are not equivalent in maintaining the dispersion of sludge and the removal or prevention of varnish deposits.

2. Description of the Prior Art US. Pat. No. 1,888,023 teaches the use of tert.-alkyl amines for color stabilizers. US. Pat. No. 2,832,74l teaches the use of tert.-amines for color stabilizers in bright stock.

SUMMARY OF THE INVENTION Beta-substituted primary amines bonded to a tert.-carbon atom, wherein the beta-substituent is an oil solubilizing hydrocarbon group bonded to the tert.-alkyl group through a heteroatom, are used as detergents and dispersants in lubricating oils to prevent sludge deposition and varnish formation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The compositions of this invention will, for the most part, have the following formula:

wherein R is an oil solubilizing group of from l to 30 carbon atoms, usually aliphatic, either branched or straight chain, and having from 0 to I site of olefinic unsaturation, usually saturated aliphatic and straight chain. R and R are lower alkyl of from I to 3 carbon atoms, more usually lower alkyl of one carbon atom, i.e., methyl. X is a heteroatom, either oxygen, nitrogen (the third valence of nitrogen being satisfied by hydrogen or hydrocarbon of from one to six carbon atoms) or sulfur. If sulfur, the sulfur may be present in its reduced state i as thioether, or in its oxidized state as the sulfoxy or sulfone.

Preferred compositions will have R and R as methyl and R as alkyl of from 12 to 28 carbon atoms.

The hydrocarbon group of the beta-substituent may be bonded to the heteroatom, either terminally or internally. The carbon atom bonded to the heteroatom may be primary, secondary, or tertiary. The hydrocarbon group may be a single hydrocarbon group or a mixture of hydrocarbon groups, derived either from synthetic or natural sources. The hydrocarbon group may be obtained by the low-pressure polymerization of olefins of from two to five carbon atoms, e.g., ethylene, propylene, butene-l, isobutylene, etc., using aluminum alkyl catalysts, by wax-cracking, etc.

Illustrative compositions included in the above formula are l-(N-octadecylamino)-2-amino-2-methylpropane, l -(N- tetradecyl-N-ethylamino)-2-amino-2-methylpropane, l-(N- eicosyl-N-methylamino)-2-amino-2-methylpropane, l-(N-octacontylamino)-2-amino-2-methylpropane, l-(N-octadecylamino)-2-amino-2-methylbutane, l-(N-tetracontyl-N- phenylamino)-2-amino-Z-methylbutane, l-octadecylthio-Z- amino-2-methylpropane, l-octadecylthio-2- amino-2-ethylbutane, l-tetradecylthio-2-amino-2-methylpropane, l-hexadecylthio-2-amino-2-methylpropane. l-octyldecylsulfinyl-Z- amino-Z-methylpropane, l-hexadecylsulfinyl-2-amino-2- methylbutane, l-hexadecysulfinyl-2-amino-2-methylpropane, l-hexadecylsulfonyl-2-amino-2-methylpropane, l-eicosylsulfonyl-2-amino-2-methylpropane, l-docosylthio-Z-amino-Z- methylpropane, l-eicosythio-2-amio-2-methylpropane, leicosyloxy-Z-amino-2-methylpropane, l-pentapropyleneoxy- 2-amino-2-methylpropane, l-tetraisobutyleneoxy-2-amino-2- methylpropane, l-pentaisobutyleneoxy'2-amino-2-methylbutane, l-(C alkyloxy)-2-amino-2-methylpropane, l-pentapropylenethio-Z-amino-2-methylpropane.

The various subgenera will now be considered based on variations in the heteroatom which is bonded to term-alkyl primary amine. The first subgenus is that in which nitrogen is the heteroatom.

The compositions having nitrogen as the heteroatom will, for the most part, have the following formula:

wherein R, R and R are as previously defined, and A is a hydrocarbon group of from one to six carbon atoms or hydrogen, more usually a hydrocarbon group of from one to three carbon atoms or hydrogen.

Illustrative groups for A are methyl, ethyl, propyl, phenyl, cyclopentyl, etc.

The nitrogen compositions can be readily prepared by combining a nitroalkane, wherein the nitro is bonded to a secondary carbon atom, with formaldehyde and the desired amine. The course of the reaction follows the following equation:

The nitro derivative may then be reduced to the primary amine. This reaction is described in U.S. Pat. No. 2,413,248 and in J. Am. Chem. Soc. 70 I846 (I948).

The composition having sulfur as its heteroatom will, for the most part, have the following formula:

wherein R, R and R have been defined previously and n is a number from 0 to 2.

The thioether can be prepared by displacement on the appropriate oxazoline with the desired alkyl mercaptan. Or, the thiol acid can be used, and the resulting mercaptan added to an olefin by known procedures, The displacement of the oxazoline by a mercaptan or a thiolester is described for the thiolester in US. Pat. No. 3,351,644. For the sulfinyl or sulfonyl functionalities, the sulfur may then be oxidized to the desired extent using peroxidic materials.

The compositions having oxygen as their heteroatom will, for the most part, have the following formula:

wherein R, R and R are as defined previously.

These compositions are readily prepared by reacting the alkali metal salt of a C-hydroxy substituted tert.-alkyl amine with an aliphatic halide to obtain the desired oxy ether. The

reaction may be carried out in an inert solvent such as an ether or nitrile, e.g., acetonitrile, and at temperatures in the range of about 50 to 100 C.

EXAMPLES The following examples are offered by way of illustrating and not by way of limitation.

EXAMPLE 1 Into a reaction vesselwas introduced 45.5 g. of 2-amino-2- methyl-l-propanol and 500 cc. of tetrahydrofuran. To the mixture was then added incrementally 24 g. of sodium hydride as a 50 weight percent slurry in oil. The mixture was refluxed for 1 hour, cooled and 166.5 g. of n-bromo-octadecane added. After refluxing the mixture for 1 hour, a major portion of the tetrahydrofuran was removed by distillation at atmospheric pressure. The residue was cooled to room temperature, frltered and then strippedon a steam plate. The product was distilled in vacuo, collecting the fraction boiling at 160-185 C. at 0.2 mm. Hg. The product weighed 100 g.

The product was titrated, yielding a molecular weight of 370; theoretical molecular weight of 341. Analysis: %N, 3.58. A vapor phase chromatograph of the product showed only a minor amount of material other than a single product.

As already indicated, the compositions of this invention find use as detergents and dispersants in lubricating oils 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 hydrocarbonaeeous mineral 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 from two to eight carbon atoms and alkylated aromatic hydrocarbons, and nonhydrocarbon oils, such as polyalkylene oxides, aromatic ethers, carboxyl 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.

When the detergents of this invention 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 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 mmJkg. of a dihydrocarbyl phosphorodithioate, wherein the hydrocarbyl groups are from about four 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, or aromatic or combinations 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 from about 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 excellent effectiveness of the compounds of this invention as detergents and dispersants in lubricating oils, a number of the compounds were tested in a l-G Caterpillar test (MIL-L45 199 conditions). The oil used was a Mid Continent SAE 30 oil and 12 mmJkg. of zinc di(alkylphenyl) phosphorodithioate the alkyl groups were polypropylene of about 12 to 15 carbon atoms) was included.

The following table indicates the particular derivative used, the amount used, the time for which the run was carried out and the results. Also included for comparison are the results for the base oil containing only the phosphorodithioate. The rating of groove deposits is based on a range of 0 to 100, being completely filled grooves. The rating for land deposits is based on a range of 0 to 800, 800 being completely black.

TABLE 1 Additive Wt. Groove Deposits Land Deposits Groove deposits-based on 0 to 100, 100 being completely filled.

Land deposits-based on O to 800, 800 being completely black.

VARNISH TEST An apparatus is employed comprising an aluminum block 7%X4Xl'7z in. with an oil outlet, which is fitted with heating means and a thermocouple. A glass cover is provided for the aluminum block which completely encloses the area over the aluminum block, except for the various inlets and outlets to be described. Used in the determination of varnish are piston alloy plates 4% 1% 3/l6 in. having a slope of l in. in 10 in. The alloy plate is carefully cleaned and repeatedly washed with aliphatic solvents, dried and weighed. The test plate is then introduced into the glass enclosure and firmly affixed to the aluminum block.

An oil solution is prepared comprising g. of the test oil, 60 g. of a FCC heavy oil, 2 g. of L-4 catalyst (a metal naphthenate solution which has a metals concentration which is deemed to be present in used crankcase oil of an L-4 Chevrolet Engine Test), (see U.S. Pat. No. 3,320,163, issued May 16, 1967) and 2 g. of water. The test oil was a Mid-Continent SAE 30 base oil and contained 3 weight percent of the test additive and 1.5 weight percent of the commercial additive. The mixture is homogenized in a Waring Blender for 2 min. at full power. The enclosed area is then flushed with oxygen and pressured to 5 in. (di-(n-buty)phtalate).

The oil solution is continuously agitated and dripped onto the test plate at a rate of one drop per second. During the test, the oil mixture is maintained at 66 C. and the plate is also maintained at the same temperature. When the addition is begun, the oxygen supply to the enclosure is closed and 100 cc. of NO in introduced into the enclosure. After 2 min., the oxygen supply is opened and the system pressurized to 6 in. (di-(n-butyDphthalate). The addition of NO is repeated seven times at 4-min. intervals.

The run is continued for 1 hr. at a constant temperature of 66 C. with the oil continuously recirculating. That is, the oil is returned from the enclosure to the main body of the oil. At the end of the hour, the test plate is allowed to cool. It is then washed carefully free of oil with hexanes, dried and weighed. The results are as follows reported as milligrams deposit:

TABLE I1 Additive Deposit, mg. Ex. 1 3.5 A 104.8

Commercial polyisobutenyl auccinimide of alkylene polyamine (polyisobutenyl 1,000 mol wt.)

In order to further demonstrate the effectiveness of the subject composition on reducing piston varnish, a test was carried out which will be referred to as the Ford Varnish Engine Test. A highly compounded oil was used having the following formulation: 3 weight percent of the exemplary composition of Example I; 50 mm./kg. calcium as a calcium carbonate overbased calcium mahogany sulfonate; l5 mmJkg. of zinc 0,0-dialkyl phosphorodithioate (alkyl of from four to six carbon atoms). The oil used was a mixture of Sunray BX 250 neutral oil and Sunray DX 150 bright stock in a 6.16/1 weight ratio.

The test was carried out with a six-cylinder Ford engine having a 240 cubic inch displacement. The engine conditions are the same as the cyclic conditions of the ASTM sequence VB 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 235 to 424 F. with 70 volume percent of a commercial regular grade gasoline. The fuel has 2 mil. per gallon of lead and approximately 0.1 weight percent sulfur. The engine run is carried out for 60 hrs.

The piston varnish rating was 6.5 based on a rating of 0 to 10, being clean. This compared favorably to commercially available ashless detergents in being a comparable varnish ratmg.

It is evident from the above results that the compounds of this invention, which are relatively simple, are surprisingly effective under a wide variety of conditions in internal combustion engines as detergents and dispersants. Not only do they maintain sludge dispersed in lubricating oil, but they effectively prevent varnish deposits. Because of their detergent capabilities, the composition may also be used in fuels and as emulsifiers with asphalt and in specialty oils.

l claim:-

I. A lubricating oil composition having an oil of lubricating viscosity in lubricating amounts and from 0.1 to weight percent of a compound of the formula:

wherein R is an oil solubilizing hydrocarbon group of from 10 to 30 carbon atoms, R and R are lower alkyl of from one to three carbon atoms and X is oxygen.

2. A lubricating oil composition according to claim 1, wherein R is alkyl of from 12 to 28 carbon atoms.

3. A lubricating oil composition according to claim 1. wherein the composition of the formula is present in from 0.l to 20 weight percent and said lubricating oil composition has from 1 to 50 mm./kg. of a phosphorodithioate selected from the group consisting of polyalkyleneoxy-dihydrocarbyl, zinc dihydrocarbyl and trihydrocarbyl phosphorodithioates wherein the polyalkyleneoxy and hydrocarbyl groups contain four to 36 carbon atoms.

4. A lubricating oil composition according to claim 1 wherein R and R are methyl.

5. A lubricating oil composition according to claim 1 wherein said compound is present in from 0.1 to 20 weight percent.

Claims

2. A lubricating oil composition according to claim 1, wherein R is alkyl of from 12 to 28 carbon atoms.
3. A lubricating oil composition according to claim 1, wherein the composition of the formula is present in from 0.1 to 20 weight percent and said lubricating oil composition has from 1 to 50 mm./kg. of a phosphorodithioate selected from the group consisting of polyalkyleneoxy-dihydrocarbyl, zinc dihydrocarbyl and trihydrocarbyl phosphorodithioates wherein the polyalkyleneoxy and hydrocarbyl groups contain four to 36 carbon atoms.
4. A lubricating oil composition according to claim 1 wherein R1 and R2 are methyl.
5. A lubricating oil composition according to claim 1 wherein said compound is present in from 0.1 to 20 weight percent.