JPH0251959B2 - - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION (i) Field of the Invention The present invention relates to the products obtained by the reaction of borated fatty acid esters of glycerin with succinimide and the use of said products in lubricating oil compositions. (ii) Description of the Prior Art With the crisis associated with the gradual decline in the amount of fossil fuels and the sharp increase in the price of such fuels, there is a great deal of interest in reducing the amount of fuel consumed by automobile engines etc. has come to be paid. Therefore, reducing the overall friction of the engine,
There is a great need to find lubricants that reduce the energy of the engine. U.S. Pat. No. 4,201,684 teaches lubricating oils containing sulfurized fatty acid amides, esters or ester-amides of alkoxylated amines to reduce friction between sliding metal surfaces in internal combustion engines. US Pat. No. 4,167,486 teaches certain acid esters having double bonds or dimers or trimers of such acid esters. Reduction of fuel consumption in internal combustion engines by use in lubricating oil in the engine crankcase is claimed. US Pat. No. 3,151,077 teaches the use of borated monoacylated trimethylol alkanes as automotive fuel and lubricating oil additives. This additive is taught to reduce the extent of surface ignition in internal combustion engines and inhibit carburetor deposit buildup. US Pat. No. 2,795,548 discloses the use of lubricating oil compositions containing borated glycerin monooleate. This oil composition is used in the crankcase of an internal combustion engine to reduce oxidation of the oil and reduce corrosion of metal parts of the engine. The use of borated fatty acid esters of glycerin in lubricating oils is problematic because they are moisture sensitive and easily hydrolyzed. Hydrolysis causes cloudiness and/or precipitate formation which must be filtered out before use. Also, the glycerin oleate formed as a result of hydrolysis causes bearing corrosion problems and/or precipitation problems in the presence of certain zinc dihydrocarbyl dithiophosphates and metal phenates. It has been discovered that borated fatty acid esters of glycerin can be stabilized against hydrolysis by complexing them with alkenyl or alkyl mono- or bissuccinimides. Most importantly, it has been found that lubricating the crankcase of an internal combustion engine with a lubricating oil containing the reaction product of a borated fatty acid ester of glycerin and succinimide reduces the fuel consumption of that engine. This is what happened. SUMMARY OF THE INVENTION In accordance with the present invention, a lubricating oil is provided that reduces friction between sliding metal surfaces and is particularly useful for crankcases of internal combustion engines. Friction is reduced by adding to the lubricating oil a small amount of a complex prepared by the reaction of a borated fatty acid ester of glycerin with polyisobutenyl mono- or bissuccinimide. Accordingly, the present invention provides an oil of lubricating viscosity, and (a)
A lubricating oil composition comprising an effective amount to reduce friction of a complex prepared by reaction of a borated fatty acid ester of glycerin or a mixture thereof and (b) an oil-soluble polyisobutenyl mono- or bissuccinimide. . The lubricating oil of the present invention includes other components in the lubricating oil to obtain the proper balance of properties such as dispersibility, corrosion resistance, wear resistance, and antioxidant properties that are important for the proper operation of an internal combustion engine. Additives may also be present. Further in accordance with the present invention there is provided a method of reducing the fuel consumption of an internal combustion engine by treating the moving surfaces of the engine with the aforementioned lubricating oil composition.
In particular, fuel mileage improvements of an average of 2-3% have been observed in engine tests. This improvement in fuel consumption is due to compression-ignition engines, i.e. diesel engines and spark-ignition engines.
It can be obtained with both ignition engines, i.e. gasoline engines. DETAILED DESCRIPTION OF THE INVENTION Borated fatty acid esters of glycerin are prepared by borating fatty acid esters of glycerin with boric acid while removing the water of reaction. Preferably, the boron is present in an amount sufficient so that each boron reacts with 1.5 to 2.5 hydroxyl groups present in the reaction mixture. The above reaction can be carried out in the absence or presence of any suitable organic solvent such as methanol, benzene, xylene, toluene, neutral oil, etc.
It can be carried out at temperatures within the range of 135°C to 135°C. Fatty acid esters of glycerin can be produced by various methods well known in the art. Many of these esters, such as glycerin monooleate and glycerin tallowate, are manufactured on a commercial scale. Esters useful in the present invention are preferably oil soluble and prepared from _C8 to _C22 fatty acids or mixtures thereof, such as those found in natural products. Fatty acids may be saturated or unsaturated. Certain compounds present in acids from natural sources include lycanic acid, which has one keto group. Most preferred _C8 - _C22 fatty acids have the formula R--, where R is alkyl or alkenyl.
This is indicated by COOH. Fatty acid monoesters of glycerin are preferred, but mono- and di-esters can also be used. Preferably, the mono- and di-esters contain at least 40% monoester. Most preferably, the mono- and diesters of glycerin contain 40-60% by weight monoester. for example,
Commercially available glycerin monooleate contains a mixture of 45-55% by weight monooleate and 55-45% diester. Preferred fatty acids are oleic acid, stearic acid, isostearic acid, palmitic acid, myristic acid, palmitoleic acid, linoleic acid, lauric acid, linoleic acid and oleostearic acid and the natural products tallow, coconut oil, olive oil, peanut oil, corn oil , fatty acids from cow leg oil, etc. A particularly preferred acid is oleic acid. Borated fatty acid esters are stabilized against hydrolysis by reacting the esters with polyisobutenyl mono- or bissuccinimide. The oil-soluble polyisobutenyl mono- or bissuccinimide used in the present invention is generally known as a lubricating oil detergent and is described in U.S. Pat.
No. 2992708, No. 3018291, No. 3024237, No. 3100673, No. 3219666, No. 3172892,
and No. 3272746, the disclosures of which should be referred to herein. Alkenyl succinimides are the reaction products of polyolefin polymer-substituted succinic anhydride and amines, preferably polyalkylene polyamines. Succinic anhydride substituted with polyolefin polymers is obtained by reaction of polyolefin polymers or derivatives thereof with maleic anhydride. The succinic anhydride thus obtained is reacted with an amine compound.
Many methods for making alkenyl succinimides have been described in the art. For example, U.S. Pat. No. 3,390,082, U.S. Pat.
No. 3172892, the disclosures of which are incorporated herein by reference. Reduction of alkenyl-substituted succinic anhydrides gives the corresponding alkyl derivatives. Products consisting primarily of mono- or bis-succinimide can be prepared by controlling the molar ratios of the reactants. For example, reacting one mole of an amine with one mole of alkenyl or alkyl substituted succinic anhydride produces a primarily mono-succinimide product. Bis-succinimide can be produced by reacting 2 moles of succinic anhydride with 1 mole of polyamine. Particularly good results are obtained in the lubricating oil compositions of the present invention when the alkenyl succinimide is a polyisobutene-substituted succinic anhydride of a polyalkylene polyamine. Polyisobutene, from which polyisobutene-substituted succinic anhydride is obtained, is obtained by polymerization of isobutene and its composition varies widely. The average number of carbon atoms ranges from 30 or less to 250 or more, and the resulting number average molecular weight accordingly ranges from about 400 or less to 3000 or more. The average number of carbon atoms per molecule of polyisobutene ranges from about 50 to about 100, and accordingly the number average molecular weight ranges from about 600 to about 1500.
Preferred is polyisobutene having More preferably, the average number of carbon atoms per polyisobutene molecule ranges from about 60 to about 90, and from about 800 to about
It has a number average molecular weight in the range of 1300.
Polyisobutene is reacted with succinic anhydride by well known methods to obtain polyisobutene-substituted succinic anhydride. When producing alkenyl succinimide,
A substituted succinic anhydride and a polyalkylene polyamine are reacted to obtain the corresponding succinimide. Each alkylene group of the polyalkylene polyamine usually has up to about 8 carbon atoms. The number of alkylene groups ranges up to about 8. Examples of alkylene groups are ethylene, propylene, butylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, octamethylene, and the like. The number of amino groups is generally, but not necessarily,
1 or more than the number of alkylene groups present in the amine, that is, when the polyalkylene or polyamine has 3 alkylene groups, usually 4
Contains 2 amino groups. The number of amino groups ranges up to about 9. The alkylene group is about 2 to
Preferably, it has about 4 carbon atoms and all amine groups are primary or secondary. In this case, the number of amine groups is one more than the number of alkylene groups. Preferably, the polyalkylene polyamine has 3 to 5 amine groups. Specific examples of polyalkylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, tripropylenetetramine, tetraethylenepentamine, trimethylenediamine, pentaethylenehexamine, di-(trimethylene)triamine, tri(hexamethylene). This includes tetramine. Other amines suitable for preparing polyisobutenyl succinimide useful in the present invention include cyclic amines such as piperazine, morpholine and dipiperazine. The polyisobutenyl succinimide used in the composition of the invention preferably has the following formula: (wherein a R ₁ is prepared from isobutene and has an average number of carbon atoms and a number average molecular weight as described above; b an "alkylene" group having up to about 8 carbon atoms;
Preferably it represents a substantially hydrocarbyl group having about 2 to 4 carbon atoms as described above; c A represents a hydrocarbyl group, an amine-substituted hydrocarbyl group or hydrogen. The hydrocarbyl and amine-substituted hydrocarbyl groups are generally alkyl and amine-substituted alkyl analogs of the alkylene groups described above. Preferably A represents hydrogen. d n represents an integer of about 1 to 10, preferably about 3 to 5). Polyisobutenyl succinimide stabilizes the borated fatty acid esters against hydrolysis and acts as a dispersant in the lubricating oil compositions of the present invention, forming in said oil during engine operation. present in an amount effective to prevent contaminant build-up. The complex, whose exact structure is unknown, is created by reacting a borated fatty acid ester of glycerin with succinimide at a temperature above the melting point of the reactant mixture and below the decomposition temperature, either alone or by dilution in which both reactants dissolve. It can be formed by reacting in a medium. For example, the reactants can be combined in suitable ratios in the absence of a solvent to form a homogeneous product that can be added to an oil, or combined in suitable ratios in a solvent such as toluene, chloroform, etc.
The complex formed by stripping off the solvent may be added to the oil. Alternatively, the complex can be prepared in a lubricating oil as a concentrate containing about 10-90% by weight of the complex, and the concentrate can be added to the lubricating oil used in an appropriate amount, or the complex can be used in a lubricating oil. It can also be produced directly in lubricating oil. The diluent is preferably inert to the reactants and is used in an amount sufficient to completely dissolve the reactants and to sufficiently stir the mixture. The temperature for preparing the above complexes is in the range from 25°C to 200°C, preferably from 25°C to 100°C, depending on whether the complex is prepared in the absence of a mixture or in a diluent, with no solvent present. When used, relatively low temperatures can be used. The weight percent ratio of succinimide:glycerin borated fatty acids for complex formation is from 0.5:1 to
3:1, preferably 1:1 to 2:1 and most preferably 1:1. The latter ratio is preferred if the complex is prepared and/or stored without admixture or in the absence of solvents, in lubricating oil or under atmospheric conditions. The amount of additive required to effectively reduce friction in a lubricant composition is the amount of additive required to effectively reduce friction in a lubricant composition.
ranging from 0.3 to about 10% by weight, preferably from 1 to about 10% by weight.
Present within 5% by weight. The succinimide is present in the complexes of the invention in an amount effective to stabilize the borated ester against hydrolysis and in an amount such that the borated ester functions as an effective lubricant. The succinimide in the complex also acts as a dispersant, preventing the deposition of contaminants that form in the oil during engine operation. In general, the complexes of the invention can also be used in combination with other additive systems in amounts customary for their known purposes. For example, for applications in new style crankcases, supplementary additives may be added to the base composition to provide the necessary stability, detergency, dispersibility, wear resistance and corrosion protection. It is blended with That is, as another aspect of the present invention, a lubricating oil containing a complex produced by reacting a borated fatty acid ester of glycerin with succinimide,
Group metal salts of alkali metal or alkaline earth metal hydrocarbyl sulfonates, alkali metal or alkaline earth metal phenates and dihydrocarbyl dithiophosphoric acids can be included. Additionally, since succinimide acts as an excellent dispersant, additional succinimide can be added to the lubricating oil composition in excess of the amount required to form a complex with the borated fatty acid ester of glycerin. The amount of succinimide ranges up to about 20% by weight of the total lubricating oil composition. The alkali metal or alkaline earth metal hydrocarbyl sulfonates can be any petroleum sulfonates, synthetic alkylated aromatic sulfonates or fatty acid sulfonates such as those derived from polyisobutene. One of the more important functions of sulfonates is to act as detergents and dispersants. These sulfonates are well known in the art. The hydrocarbyl group must contain a sufficient number of carbon atoms to make the sulfonate molecule oil-soluble. The hydrocarbyl moiety preferably has at least 20 carbon atoms and may be aromatic or aliphatic, but is usually alkyl aromatic. Most preferred for use are aromatic calcium, magnesium or barium sulfonates. Certain sulfonates are typically prepared by sulfonating petroleum fractions having aromatic groups, usually mono- or dialkylbenzene groups, and then forming metal salts of the sulfonic acid material. Other feedstocks used for the production of these sulfonates include synthetic alkylated benzenes and synthetically produced by the polymerization of mono- or di-olefins such as polyisobutenyl groups produced by the polymerization of isobutene. This includes aliphatic hydrocarbons. Metal salts are formed directly or by metathesis using well known methods. The sulfonate may be neutral or overbased with a base number of up to about 400 or more. Carbon dioxide and calcium hydroxide or oxide are the materials most commonly used in the production of basic or overbased sulfonates. Neutral and overbased sulfonates can also be used. Sulfonates are typically used in amounts ranging from 0.3 to 10% by weight of the total composition. Preferably, the neutral sulfonate is present at 0.4-5% by weight of the total composition and the overbased sulfonate is present at 0.3-3% by weight of the total composition. Phenates for use in the present invention are common products that are alkali metal or alkaline earth metal salts of alkylated phenols. One of the functions of phenates is to act as detergents and dispersants. In particular, phenates prevent the build-up of contaminants that form during high temperature operation of the engine. The phenols may be mono- or polyalkylated. The alkyl portion of the alkyl phenate is present to make the phenate oil-soluble. Alkyl moieties can be obtained naturally or synthetically. Naturally occurring raw materials include petroleum hydrocarbons such as liquid paraffin and wax. Because it is derived from petroleum, its hydrocarbon portion is a mixture of disparate hydrocarbyl groups, and the specific composition depends on the particular crude oil used as a starting material. Suitable synthetic raw materials include a variety of commercially available alkenes and alkane derivatives that produce alkylphenols when reacted with phenols. Suitable groups available include butyl, hexyl, octyl, decyl, dodecyl, hexadecyl, eicosyl, tricontyl, and the like. Other suitable synthetic raw materials for alkyl groups include polypropylene,
Included are olefin polymers such as polybutylene, polyisobutylene, and the like. The alkyl group may be straight chain or branched, saturated or unsaturated (if unsaturated, it preferably contains no more than 2 sites, and generally no more than 1 site, of olefinic unsaturation). The alkyl group mentioned above is
Generally contains 4 to 30 carbon atoms. When the phenol is monoalkyl substituted, the alkyl group should generally contain at least 8 carbon atoms. The phenate may be sulfurized if desired. The phenate can be either neutral or overbased, and if overbased has a base number of 200-300 or more. Mixtures of neutral and overbased phenates can be used. Phenotes are usually present in lubricating oils in an amount of 0.2 of the total composition.
Present at ~27% by weight. Preferably, the neutral phenate is present at 0.2-9% by weight of the total composition and the overbased phenate is present at 0.2-13% by weight of the total composition. Overbased phenate is present in the total composition.
Most preferably present from 0.2 to 5% by weight. Preferred metals are calcium, magnesium, strontium or barium. Sulfurized alkaline earth metal alkyl phenates are preferred. These salts are obtained by various methods such as treating the neutralization product of an alkaline earth metal base with an alkylphenol with sulfur. Conveniently, sulfur in elemental form is added to the neutralization product and reacted at elevated temperatures to produce the sulfurized alkaline earth metal alkyl phenate. If more alkaline earth metal base is added than necessary to neutralize the phenol during the neutralization reaction, a basic sulfurized alkaline earth metal alkyl phenate is obtained. For example, U.S. Pat.
See the method of Walker et al., No. 2,680,096. Additional basicity is obtained by adding carbon dioxide to the basic sulfurized alkaline earth metal alkyl phenate. Although excess alkaline earth metal base may be added after the sulfidation step, it is convenient to add it at the same time as the alkaline earth metal base is added to neutralize the phenol. Carbon dioxide, calcium hydroxide or calcium oxide are the materials most commonly used to make basic or "overbased" phenates. A method for making basic sulfurized alkaline earth metal alkyl phenates by the addition of carbon dioxide is shown in Hanneman, US Pat. No. 3,178,368. Group metal salts of dihydrocarbyl dithiophosphoric acids exhibit wear resistance, antioxidant properties and thermal stability.
Group metal salts of phosphorodithioic acids have been previously described. See, for example, U.S. Pat.
See columns 6 and 7 of issue 3390080.
Group metal salts of dihydrocarbyl dithiophosphoric acids useful in the lubricating oil compositions of the present invention preferably contain from about 4 to about 12 carbon atoms in each hydrocarbyl group, which may be the same or different. It may be an aromatic group, an alkyl group, or a cycloalkyl group. Preferred hydrocarbyl groups are alkyl groups having 4 to 8 carbon atoms, such as butyl, isobutyl, sec-butyl, hexyl, isohexyl, octyl, 2-ethylhexyl.
Suitable metals for forming these salts include barium, calcium, strontium, zinc and cadmium, with zinc being preferred. The Group metal salt of dihydrocarbyl dithiophosphoric acid has the following formula: (wherein each of e R ₂ and R ₃ independently represents a hydrocarbyl group as defined above and f M ₁ represents a Group metal cation as defined above). The dithiophosphate is present in the lubricating oil compositions of the present invention in an effective amount so that the lubricating oil exhibits wear resistance and antioxidant properties. The amount may range from about 0.1% to about 4% by weight of the total composition, preferably from about 0.2% to about 4% by weight of the total lubricating oil composition.
Present in an amount in the range of about 2.5% by weight. The finished lubricating oil composition typically contains 0.025 to 0.25% by weight phosphorus, preferably 0.05 to 0.15% by weight. The finished lubricant may be single grade or multigrade. Multigrade lubricating oils are produced by the addition of viscosity index improvers (). Typical viscosity index improvers are polyalkyl methacrylates, ethylene propylene copolymers, styrene diene copolymers, and the like. So-called decorated viscosity index improvers, which combine viscosity index improving and dispersing properties, are also useful in the formulations of this invention. The lubricating oil used in the composition of the invention is
A mineral or synthetic oil of lubricating viscosity, preferably suitable for use in the crankcase of an internal combustion engine. Crankcase lubricants typically have approx.
1300cst.0〓(−17.8℃)～22.7cst.210〓(99℃)
It has a viscosity of Lubricating oils may be derived from synthetic or natural sources. Mineral oils for use as base oils of the present invention include paraffinic, naphthenic and other oils commonly used in lubricating oil compositions. Synthetic oils include both hydrocarbon synthetic oils and synthetic esters. Useful synthetic hydrocarbon oils include liquid polymers of alpha-olefins of suitable viscosities. Particularly useful are hydrogenated liquid oligomers of _C6 to _C12 alpha-olefins, such as 1-decentrimers. Similarly, alkylbenzenes of suitable viscosity, such as didodecylbenzene, can also be used. Useful synthetic esters include esters of both monocarboxylic and polycarboxylic acids and esters of both monohydric and polyhydric alcohols. Typical examples are didodecyl adipate, pentaerythritol, tetracaproate, di-2-ethylhexyl adipate, dilauryl sebacate, and the like. Mono- and dicarboxylic acids and mono-
Complex esters prepared from mixtures of and dihydroxy alkanols can also be used. Mixtures of hydrocarbon and synthetic oils are also useful.
For example, a mixture of 10-25% by weight hydrogenated 1-decentrimer and 75-90% by weight 150SUS (38 DEG C.) mineral oil makes an excellent lubricating base oil. Additive concentrates are also within the scope of this invention. These typically contain about 90-10% by weight of oil of lubricating viscosity and about 10-90% by weight of the complex additive of the invention. Typically, the concentrate contains sufficient diluent to facilitate handling during transportation and storage. Suitable diluents for concentrates include any inert diluent, preferably an oil of lubricating viscosity, so that the concentrate can be readily mixed with a lubricating oil to produce a lubricating oil composition. . Suitable lubricating oils that can be used as diluents typically have a 100%
About 35 to about 500 Saybolt Universal Seconds (SUS) at (38℃)
However, oils of lubricating oil viscosity may also be used. Other additives that may be present in the formulation include rust inhibitors, foam inhibitors, corrosion inhibitors, metal deactivators, pour point depressants, antioxidants and various other additives. The following examples are intended to explain the invention in detail. These examples and illustrations are not to be construed as limiting the scope of the invention in any way. Reference Example 1 Production of borated glycerin monooleate 125.23 g of glycerin monooleate (45-55
wt%) and glycerin dioleate (55-45
% by weight), 30.92 g of boric acid and 250 ml of xylene were added. The reaction mixture was heated at 99-141 °C under nitrogen in azeotrope conditions of approximately 9.5
The time was hot. Dean Stark Trap
17.6 ml of water was collected by the Stark trap.
The reaction product was filtered and stripped on a rotary evaporator at 135° C. under reduced pressure to yield 128.35 g. Analysis: Boron 2.42%, and hydroxyl number 2.52%
It was 32mgKOH/g. Infrared spectroscopy of the product showed no stretching of the glycerin-type OH, but it did have a strong BO-H bond, effectively
-O-B type absorption was not exhibited. Example 2 CC100N oil was used, containing 1% by weight of the borated glycerin oleate prepared in Example 1, and 0.66% by weight of polyisobutenyl succinimide (polyisobutenyl succinic anhydride with a polyisobutenyl number average molecular weight of about 950). and tetraethylenepentamine at a molar ratio of amine:anhydride of 0.87) to form a complex on the spot, and the test results for those that do not contain this are shown in Table 1. Indicated. 150 ml of each base oil and mixture was placed in a 250 ml beaker and placed in a humidity cabinet maintained at 100% and 90% relative humidity. Samples were graded for haze and sediment as a function of time.

[Table] Nil succinimide

Claims (1)

[Claims] 1. A method for stabilizing a borated fatty acid ester of glycerin used in a lubricating oil against hydrolysis, the method comprising: stabilizing the borated fatty acid ester of glycerin at a temperature of 25°C to 200°C; and a polyisobutenyl succinimide having from 30 to 250 carbon atoms to form a complex that is stable to hydrolysis, wherein a borated fatty acid ester of said polyisobutenyl succinimide and glycerin is reacted with 1. A method for stabilizing a borated fatty acid ester of glycerin, the method comprising: adjusting the weight ratio of 0.5:1 to 3:1. 2. The borated fatty acid ester of glycerin is borated glycerin oleate or a mixture containing it, and the succinimide is
The method according to claim 1, wherein the polyalkylene polyamine is polyisobutenyl succinimide. 3. The method according to claim 2, wherein the succinimide is polyisobutenyl succinimide of triethylenetetramine or polyisobutenyl succinimide of tetraethylenepentamine. 4. Claim 2, wherein the borated fatty acid ester of glycerin is a mixture containing 45 to 55% by weight of borated glycerin monooleate and 55 to 45% by weight of borated glycerin dioleate. the method of. 5. The method according to claim 2, wherein the borated fatty acid ester of glycerin is borated glycerin monooleate. 6. Claim 5, wherein the weight ratio of the polyisobutenyl succinimide to the borated fatty acid ester of glycerin is in the range of 1:1 to 2:1.
The method described in section.