US3903151A

US3903151A - Reaction products of alkali metal meborate and hydrocarbon substituted succinimide

Info

Publication number: US3903151A
Application number: US438966A
Authority: US
Inventors: Warren Lowe
Original assignee: Chevron Research and Technology Co
Current assignee: Chevron USA Inc
Priority date: 1971-07-14
Filing date: 1974-02-04
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02

Abstract

Compositions are provided useful in lubricating oil for detergency, dispersancy, antiwear and acid neutralization, which are the reaction product of an alkali metal metaborate and a succinimide in the presence of water, the presence of excess alkali metal metaborate being contemplated.

Description

United States Patent Lowe Sept. 2, 1975 [54] REACTION PRODUCTS OF ALiKALI METAL 328L428 l0/l966 LeSuer 260/3263 MEBORATE AND HYDROCARBON 3.282.955 ll/l966 LESUCI'H 260/3263 3.3l3 727 4/1967 Peeler 260/534 SUBSTITUTED SUCCINIMIDE 3,322.670 5/l967 Burt et al .i 260/3263 [75] Inventor: Warren Lowe, El Ccrrit0 Califi 3.344.069 9/[967 Stuebc 252/496 3.449362 6/1969 Lee 260/3263 [73] Assignee: Chevron Research Company, San

Francisco, Calif. Primary I:'.\uminer-J0hn F. Terapane [22] Ffled' 1974 Attorney, Agent/or FirmG. F. Magdeburger; C. J. [21] Appl. No.: 438,966 Tonkin Related US. Application Data [60] Continuation of Ser. No. 163.542, July 14, l97l.

abandoned. which is a division of Ser. No. 31,4]2. [57] ABSTRACT April 23. 1970. Pat. NO. 3,666.662.

Compositions are provided useful in lubricating oil for 52 U.S. Cl 260/534 R detergency dispersancyand acid neumlim' I C07c 103/44 tion, which are the reaction product of an alkali metal 88] Field of Search 260/534 R metabome and succinimide the Presence ter, the presence of excess alkali metal mctaborate [56] References Cited bemg contemplated UNITED STATES PATENTS 3 Claims No Drawings 3,087,936 4/1963 LeSucr 260/3263 REACTION PRODUCTS OF ALKALI METAL MEBORATE AND HYDROCARBON SUBSTITUTED SUCCINIMIDE CROSS-REFERENCE TO RELATED APPLICATIONS f This application is a continuation of copending-application Ser. No. 163,542, filed July 14, l97l, now abandoned which in turn was a divisional of application Ser. No. 31,412, filed Apr. 23, 1970, which issued on May 20, 1972 as US. Pat. Ndf3,66 6,662.

BACKGROUND OF THE INVENTION l. Field of the Invention In the area of lubrication, there'has been a continuous effort to provide protection from wear and to reduce deposits that form on moving or stationary parts in internal combustion engines. Among additives which have found wide use as detergents in lubricating oils under a wide variety of conditions, e.g., automobile gasoline engines and diesel engines, are succinimides of alkylene polyamines. These succinimides have been re ported in numerous patents and have proven to be extremely efficient in maintaining deposits dispersed in oil.

The succinimides, however, provide little if any wear protection. Wear can occur in a variety of areas, by a variety of mechanisms, e.g.', corrosion, adhesion, and abrasion. There are numerous chemicals which operate in a variety of ways to reduce wear. Compounds containing halogenaphosphorus, or sulfur are believed to react with the surface to provide a surface which wears more slowly than would occur in the absence of these compounds. Carboxylic acids have been employed which may be adsorbed onto the surface to provide a protective layer. Zinc compounds are also used, which under certain conditions form a nonsacrificial layer to protect the original surface.

Also, since acids are frequently formed in internal combustion engines; hydrohalide acids in automobile engines and sulfuric acids in diesel engines, sources of base are added to neutralize such acids and prevent them fromcorroding the metal. Various sources include overbased sulfonates, phenates, and phosphonates.

2. Description of the Prior Art US. Pat. Nos. 3,087,936, 3,344,069, and 3,449,362 teach succinimides of alkylene polyamines or polyureas in combination with boric acid, boric acid esters and borohalide complexes. The combinations of the succinimides and boric acid derivatives are taught as having dete'rgency, rust inhibition, corrosion inhibition, extreme pressure activity, antiwear activity, as well as useful for pesticides and plasticizers. U.S. Pat. No., 3,087,936 (column 2I, lines 2630). See also US. Pat. I

US. Pat. No. 3,281,428 teaches the use of succinimides of amines other than alkylene polyamines in combination with a variety ofboric acidderivatives, in-

cluding in addition to those mentioned above. the ammonium salts of such boron acids. See also US. Pat.

with complex forming metal compounds.Illustrative; 65

ence of a small amount ofa dispersant such as a succinimide or sulfonate: These borates are prepared in amorphous form in an oil medium and provide extreme pressure activity.

VSILJMMARYQOFTHE INVENTION N'ovel compositions are prepared by reacting at'elevatedtemperatures at least 0.8 mols of an alkali metal metaborateper mol of .a succinimide of an alkylene polyamine to form analkali metal succinanatecomposition which forms a stable dispersion in a hydrocarbon oil medium. The reaction is carried out in the presence of a hydroxylic compound, e.g., water, -usually at least about 4 molslof the hydroxylic compound per mol of the alkali metal metaborate being present. The compositions find use in lubricating oils for internal combustion engines, providing detergency and dispersancy as well as protection from wear, not only by acid neutralization, butalso by protecting from corrosion, abrasive and adhesive wear.

DETAILED DESCRIPTION OF THE INVENTION The novel compositions of this invention are alkali metal succinamates prepared by the reaction of an alkali metal metaborate and a succinimide of an alkylene polyamine in the presence of a hydroxylic solvent. Preferred in combination with this composition is an excess of alkali metal metaborate of fromabout l to 20 mols, more usually from about 2 to 12 mols.

In the reaction to form the succinamate salt, the fate of the metaborate residuejs not certain. It may become chemically combined with the succinamate salt or become a boron oxide derivative which remains'dispersed in the medium. -l i t I The compositions of this invention may. therefore,be

considered to have the following formula:

wherein? I r M is an alkali metal of atomic number I l to-l 9 (sodium or potassium), preferably sodium;

one of R and R is hydrogen and the other is ahydrocarbon group of at least about 50 carbon atoms and usually not morethan about 300 carbon atoms, more usually from about 60 to 200. carbon atoms;

U is alkylene of from 2 to ocarbon atoms more usu- Y is the boron oxide residue from the reaction of the metal metaborate with the succinimide; and X is amino; succinimide'of the formula;

wherein R and R have beenpreviously defined; or suc cinamate of the formula:

wherein R, R and M have been defined previously.

When greater than I mol of the alkali metal metaborate is employed per mol of a monosuccinimide or greater than two mols of an alkali metal metaborateis employed per mol of a bis-succinimide. the resulting composition will have the following formula:

wherein R. R, M, U. n, and Y are as defined previously; and X is amino. or succinamate of the formula:

amal am:

l amemiwherein R, R and M are as defined previously;

p is 1 when X is amine and 2 when X is succinamate;

q is an integer or fractional number averaging over the entire compositions in the range of from O to 4, usually 1 to 3; and

r is in the range of from 1 to 20, preferably 2 to 12.

The group designated Y, from the nature and stoichiometry of the reaction, is most likely a borate, the boron oxide residue forming boric acid which forms an ammonium salt with the succinamate. In the presence of excess alkali metal metaborate, the boron oxide residue will probably be involved in a complex manner, with the excess alkali metal metaborate dispersed in the oil.

The hydrocarbon groupR or Rwill be an oil solubilizing group usually aliphatic. having one branch for 6 carbon atoms along the chain, and more usually about one branch for from 1 to 4 carbon atoms along the chain. The branches will normally be of from 1 to 2 carbon atoms. more usually of 1 carbon atom, i.e., methyl. There may be from to 2 sites of olefmic unsaturation as the only unsaturation.

Illustrative hydrocarbon groups are polypropenyl, polyisobutenyl. poly-l-butene, poly-4-methylpentenel, copolymer of ethylene and isobutylene, etc. These compositions are normally prepared by polymerizing or copolymerizing olefins of from 2 to 6 carbon atoms, ethylene being copolymerized with an olefin of from 3 to 6 carbon atoms. The copolymers are normally random. The preferred polymers are polypropyleneand polyisobutylene.

The alkali metal metaborates which are present in conjunction with the succinamates will generally be either sodium or potassium metaborate, normally having from 0 to 4 waters of hydration. more usually of from I to 3 waters of hydration.

The alkylene group designated by U. which is of from 2 to 6 carbon atoms. may be straight chain or branched. but will usually be straight chain. Illustrative alkylene groups are ethylene, propylene, 1.2-

propylene, tetramethylenc;'hexamethylene, etc. The preferred alkylene groupsare of from 2 to 3 carbon atoms, there being Z-carbon atomsbetween the nitrogen atoms.

The succinimides, which are used in the preparation of the compositions of this invention have the following formula: I

2 n -cn- 2 atumn 11x n -cnn 1 wherein:

one of R and R is hydrogen and the other is a hydrocarbon group of from to 300 carbon atoms, more usually of from to 200 carbon atoms;

' U is alkylene of from 2 to 6 carbon atoms, more usually of from 2 to 3 carbon atoms, there being at least 2 carbon atoms between the nitrogen atoms;

n is an integer of from 0 to 6, more usually in an integer of from 1 to 5; and X is amino or of the formula:

a ert- B wherein R and R are as defined previously. The illustrative description of R and R will also suffice for R and R The alkali metal metaborates which are employed in this invention will have the following formula:

wherein M is sodium or potassium; and q is a number of from 0 to 8. more usually of from 4 to 8.

'In preparing the compositions of this invention, the succinimide will conventionally be used in a suitable medium, e.g., a hydrocarbon medium. Suitable hydrocarbon media, in view of the use intended for these compositions, will normally be an oil of lubricating viscosity. These oils may be paraffinic, naphthenic or aromatic, or combinations thereof, but are preferably predominantly paraffmic.

The succinimide will generally be employed in solution in from about l() to 60 weight per cent, more usually in from about 15 to 50 weight per cent. Conveniently.the solution is heated to a temperature of at least l50F., preferably to a temperature of from about 175 to about 30()F., more usually to a temperature of from about 175 to 250F. before the introduction of the alkali metal metaborate.

To the succinimide solution is then added the alkali metal metaborate, normally dissolved in a hydroxylic solvent. The preferred hydroxylic solvent is water, although an alcohol of from 1 to 3 carbon atoms may be employed normally as mixtures with water. Usually, the alkali metal metaborate solution will be heated to the highest temperature permissible, depending on the solvent. Temperatures will, therefore, vary from a low of about 100F. to a high of about 200F. The concentration of the alkali metal metaborate in the hydroxylic solvent will normally be from about l5 to 80 weight per cent, more usually from about 25 to weight per cent. There will be at least 4 mols of water per mol of metaborat e. While the maximum amount of water or alcohol is one of convenience, usually there will not be more than about 20 mols, more usually not more than about mols of water and/or alcohol per mol of metaborate.

While at least about 0.8 mols of alkali metal metaborate will be used per mol of succinimide. the total num' ber of mols of metaborate will not exceed 22 mols per mol of succinimide. Alkali metal metaborate may be added after the completion of the reaction to further augment the metaborate initially added. Therefore. during the reaction the amount of metaborate added will usually not exceed about mols per mol of succinimide.

Vigorous agitation should be employed during the addition and subsequent to the addition of the alkali metal metaborate. Any high speed and, preferably, high shearing device may be used to provide the necessary agitation. After adding the alkali metal metaborate, the temperature is normally raised, usually not to exceed 400F., more usua-ly not to exceed 300F., and preferably in the range of 250 to 300F. The reaction is carried out for a time sufficient to drive off a substantial amount of the water. Normally, from about to 100 per cent, usually not more than 9071 of the water initially introduced (both as solvent and water of hydration) will be driven off. The amount of water remaining will be sufficient to provide the 0 to 4 Waters of hydration for the inorganic boron present in the so lution.

When the desired amount of water has distilled over, the heating is stopped and the reaction mixture is allowed to cool. Since the reaction mixture is normally formed as a concentrate, it can then be suitably diluted to be usedin lubricating oil compositions.

With excess alkali metal metaborate, high alkalinity values can be achieved. The preferred compositions of this invention will normally have alkalinity values of from about at least 50 to 300 mg. KOH/gram, more usually alkalinity values of from about 100 to 250, and preferably 150 to 250.

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

EXAMPLE I Into a Waring blender equipped with a heating jacket. a thermometer and stirring motor was charged 400 grams of a weight per cent solution in neutral oil of a polyisobutenyl succinimide of tetraethylene pentamine (polyisobutenyl group of about 1,000 viscosity average molecular weight) (70 N, 2.1, alkalinity value, 22 mg. KOH/gram) and 3 drops ofa foam inhibitor (DC-200 supplied by Dow Corning Company). The oil solution was heated to about 200F. with stirring. To the solution was then added 213 grams of sodium metaborate tetrahydrate in 107 ml. of distilled water. With continual stirring, the temperature was raised from 210 to about 300F. over a period of 2 hours and then maintained at that temperature for an additional half hour.

At the end of this time, the product was isolated and analyzed. Per cent N, 1.54, 1.51; alkalinity value, 201, 204 mg. KOH/gram.

EXAMPLE ll Into a Waring blender was charged 400 grams of bispolyisohutenyl succinimide of triethylene tetramine (polyisolwtenyl of about 1,000 viscosity average mo- EXAMPLE lll Following the procedure of Example II, to 400 grams of a 40 weight per cent solution of bis-polyisobutenyl succinimide of tetraethylene pentamine in a neutral oil (one polyisobutenyl group is of about 1,000 viscosity average molecular weight and the other polyisobutenyl group is about 650 viscosity average molecular weight) (7: N, 1.27; alkalinity value, 22 mg. KOH/gram) was added I 13.5 grams of sodium metaborate tetrahydrate in 57 ml. of distilled water. At the end of the reaction. after cooling, the product was analyzed. 71 N, 1.09; alkalinity value. 120 mg KOH/gram.

Succinamate salts may be used with a wide variety of hydrocarbon lubricating oils, usually derived from pctroleum or prepared synthetically. The mineral lubricating oils may be paraflinic, naphthenic. asphaltic, or compositions thereof, while the synthetic oils will normally be polymers of low molecular weight olefins. Lu bricating oils generally have viscosities of from about 35 to 50,000 Saybolt Universal Seconds (SUS) at The above oils may be used individually or together. whenever miscible or made so by the use of mutual solvents.

The compositions of this invention will be employed in lubricating oils in from 0.5 to 60 weight per cent. When in use in an internal combustion engine, the concentration will vary from 0.5 to 20 weight per cent. Concentrates will vary from 10 to 60 weight per cent, more usually 20 to 50 weight per cent.

Other additives are normally included in the oil along with the detergent antiwear additive of this invention. These additives include pour point depressants, oiliness agents, anti-oxidants, rust inhibitors, additional an tiwear additives, such as bearing corrosion inhibitors, extreme pressure-agents, as well as detergents and additional sources of alkalinity value. The individual additives will normally vary in amount from about 0.01 to 5 weight per cent of the total composition used in the engine. In concentrates, the weight per cent of these additives will usually range individually from about 0.3 to 10 weight per cent.

Two additives of particular value are dithiophosphate and terephthalic acid. Included in the lubricating oils are from about 1 to 50 mM/kg, preferably 5 to 30 mM/kg, of an 0,0-dihydrocarbyl phosphorodithioate, particularly the zinc salt, wherein the hydrocarbyl groups are of from about 4 to 36 carbon atoms. Usually, the hydrocarbyl groups will be alkyl or alkaryl. Other phosphorodithioates, such as trialkyl or polyethyleneoxy dihydrocarbyl phosphorodithioate may also be used with advantage.

Terephthalic acid, which may be used, gives greatly enhanced antiwear protection, and will normally be present in from 0.01 to 0.5, more usually from about 7 005 to 0.2 weight per cent of the total composition.

In order to demonstrate the effectiveness of thesub- The tests employ oil formulations which simulate or are substantially the same as those used commercially except forthe presence of the exemplary additives and such changes necessitated by its presence.

Two tests were carried .out to demonstrate the detergency of the subject compositions, one in an automobile internal combustion engine and the other in a diesel enginev The first test was a Sequence VB engine test which is described in Schilling, Moro!" Oils and Engine Lubrication, Scientific; Publications (OB) (1968), 3.35. In this formulation, a 100 neutral oil was compounded with 12 mM/kg of zinc dialkyl dithiophosphate (alkyl of from 4-to 5 carbon atoms), 16 mM/kg based on calcium of anoverbased calcium sulfonate, 1.6 weight: percent of sodium polyisobutenyl succinamate of tetraethylene;pentamine (polyisobutenyl of about 1,000 viscosity average: molecular weight), and 0.25 weight per cent of sodium metaborate. (approximately a 4:1 mol ratio of-metaborate to succinamate).

The results are reported for piston varnish 0 to 10, 10 being clean. For total varnish and sludge, 0 to 50, 50 being clean. The above indicated oil had the following ratings: Piston varnish 8.9; total varnish 41.9; sludge 44.1. These results demonstrate that the succinamate is an effective detergent in an automobile internal combustion engine.

ln-the Caterpillar l-H test, the test was carried out for 120 hours; In a mid-continent 200 neutral oil was formulated 1.8 weight per cent of an ethylene/propylene copolymerviscosity index improver (V- 92 SUS), 6.67 mM/kg of aneutral calcium sulfonate, 16.7 mM/kg of a sulfurised calciu'rn polypropylene phenate having about; a 1.121 calcium ratio to stoichiometric, 4.7 mM/kg of zinc 0,0-dialkylphenyl dithiophosphate (alkyl of from 12 to 15 carbon atoms), 7.3 mM/kg of zinc 0.0-dialkyl dithiophosphate (alkyl of from 4 to 5 carbon atoms), 2 weight per cent of the sodium succin amate, described in Example 1 with 0.5 weight per cent of sodium metaborate, a mol ratio of about 8.1. The engine test was carried out for 120 hours and the results are reported as follows: Grooves. 0 to 100, 100 indicating no filling of the grooves; lands, 0 to 800, 0 being clean; and underhead 0 to l0, 10 being clean. For the above formulation, the results were as follows: Grooves, 16, 2.2, 0.7, 0. 7; lands, 185, 35, underhead, 9.1.

For comparison purposes, a like formulation which did not employ the succinamate, but rather the same amount of succinimide used to form the succinamate and had no sodium metaborate present, the results were as follows: Grooves, 64, 0.8, 0.6, 0.6; lands, 155,

30, underhead, 7.1. The results clearly show that r the succinamate in combination with sodium metaborate is an effective detergent under the extremely hot conditions of the diesel engine. 1

To demonstrate the effect on wear, a number of tests were also carried out. The first test was the L-38 Engine Test, which is described in Schilling, supra. 4.31. The oil employed as a base oil was a 480 neutral oil. It was formulated with 9 mM/kg of sine 0,0-dialkyl dithiophosphate (alkyl of from 4 to 5 carbon atoms), 2.2 weight per cent of sodium succinamate described in Example 1. and 0.25 weight per cent of sodium metaborate. The test duration is 40 hours, and the bearing I 8 weight lossat the end of this time was 82.3 mg. By comparison. using the succinimide in the same amount as the succinamate and in the absence of any sodium metaborate, the bearing weight loss was 148.8 mg. When 0.1 weight per cent of terephthalic acid was added to the sodium metaborate containing oil, the result was 22.5 mg. weight loss.

A further test, which is extremely severe as an antiwear test, is the Ford Valve Train Wear Test. The engine employed is a 1967-1968 Ford, 240 CID sixcylinder engine equipped with a single barrel carbure tor with a blocked throttle to prevent engine speed from exceeding 1050 RPM, a closed crankcase filtration system and an oil filter. Additionally, a heating system is employed inthe oil pan to provide a temperature of the heating element of approximately 267F. To provide enhanced severity in the valve train the valve springs are overloaded 21%. A normal leaded fuel is employed.

The engine is thoroughly flushed to remove any traces of prior additives and then filled with 5 quarts of test oil. The spark advance is set at 6 BTDC at 1000 RPM and the engine is run with no load for a total running time of 60 hours. Speed is maintained at 1000 RPM, oil temperature at 220F. and exit water temperature at 200F. Two 4 07.. samples are taken during the test, one at 30 hours and one at 60 hours. At the end of the run, the valve tips are examined by profilometer and the profilometer traces are measured by planimeter to determine the Cross sectional area.

In this test, the base oil was a /200 mid-continent base stock, containing 7.4 weight per cent of an acrylate detergent viscosity improver, 40 v mM/kg of an overbased calcium sulfonate (9.9;1 calcium ratio) 9 mM/kg of Zinc o,o-dialkyl dithiophosphate (alkylof from 4 to 5 carbon atoms) and 1.3 weight per cent of the sodium succinamate described in Examplel. \j arying amounts of sodium succinamate were employed. The results are reported in per cent reduction in tip wear relative to the reference oil which uses the succinimide in place of the succinamate and sodium metaborate. At 0.25 weight per cent of sodium metaborate, there was a 58 weight per cent reduction in tip wear, while at 0.50 weight per cent sodium metaborate, there was a 51 weight per cent reduction.

When the zinc dithiophosphate was replaced with a different zinc dialkyl dithiophosphate, differing only in the structure of the alkyl groups, and at the same concentration, with 0.50 weight per cent of sodium metaborate, 71 per cent reduction in tip wear was achieved.

In addition, the compositions of this invention are found to be effective additives against rust and other types of wear.

ltis evident from the above results that the succinamates of this invention, particularly in combinations with excess alkali metal metaborates, are extremely effective additives in not only providing detergency which has been previously known for succinimides, but providing antiwear and an alkalinity source. The additives are compatible with a wide variety of other additives normally included in lubricating oils and provide bright. compounded oil compositions. The presence of the succinamate as a detergent, provides desirable relatively low ash formulated compositions.

lclaimzm l. product produced by reacting an alkali metal metaborate .of the formula;

wherein M is sodium or potassium and q is a number from U to 8; and a succinimidc of the formula:

n is an integer of from (i to (a; and

X is amino: in a moi ratio of from 0.8 to 22 mol of said mctahoratc per mol of said succinimidc. in the presence of at least 4 mols of water per mol of said metaborutc. at a temperature of about I()U-4U()F for a time sufficient to drive off 20-1007: of water 2. The product of claim 1 wherein R or R is of from to 200 carbon atoms. U is of from 2 to 3 carbon atoms and n is from i to 5.

3. The product of claim 1 wherein R or R is a polyisobutyl group. said metaborate is sodium metaborate tetrahydrate and said succinimide is a succinimide of tetraethylene pentamine.

Claims

1. THE PRODUCT PRODUCED BY REACTING AN ALKALI METAL METABORATE OF THE FORMULA:

2. The product of claim 1 wherein R or R1 is of from 60 to 200 carbon atoms, U is of from 2 to 3 carbon atoms and n is from 1 to 5.

3. The product of claim 1 wherein R Or R1 is a polyisobutyl group, said metaborate is sodium metaborate tetrahydrate and said succinimide is a succinimide of tetraethylene pentamine.