ES2620681T3 - Marine Engine Lubrication - Google Patents

Abstract

A lubricating oil composition for tubular piston marine engines, to improve the handling of asphaltenes in the use thereof, in the operation of such an engine when fed by heavy fuel oil, a composition comprising, or prepared by mixing, a oil of lubricating viscosity and, in respective minor amounts: (A) an over-alkali metal hydrocarbyl-substituted hydroxybenzoate detergent system, and (B) a hydrocarbyl-substituted succinic acid anhydride, preferably prepared using halogen or radical assisted functionalization procedures , where the ratio of succinic anhydride groups to substituted hydrocarbyl moiety is in the range of 1.4 to 4, preferably 1.4 to 3; wherein the anhydride (B) constitutes at least 0.1 to 10% by mass, based on the active ingredient, of the lubricating oil composition.

Description

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DESCRIPTION

Lubrication of marine engines Field of the invention

This invention relates to the lubrication of marine tubular piston engines for a four-stroke medium-speed marine (diesel) compression ignition engine.

Background of the invention

Tubular piston marine engines generally use Heavy Fueloil ("HFO") to operate on the high seas. Heavy Fueloil is the heaviest fraction of petroleum distillate, and comprises a complex mixture of molecules that include up to 15% of asphaltenes, defined as the fraction of petroleum distillate that is insoluble in an excess of aliphatic hydrocarbon (eg. heptane) but which is soluble in aromatic solvents (eg toluene), measured by ASTM D6560. The asphaltenes can enter the engine lubricant as contaminants, either through the cylinder or the pumps and fuel injectors, and then the asphaltene precipitation can occur, manifested in "black paint" or "black mud" in the engine. The presence of such carbonaceous deposits on the surface of a piston can act as an insulating layer that can result in the formation of cracks that propagate afterwards through the piston. If a crack travels through the piston, hot combustion gases may enter the crankshaft housing, possibly resulting in an explosion of the crankshaft housing.

It is therefore highly desirable that tubular piston engine oils ("TPEOs") prevent or inhibit asphaltene precipitation, a problem that becomes more acute when the oil of lubricating viscosity has a Saturated content higher. The prior art describes ways of doing this by using metal carboxylate detergents in combination with a carboxylic acid anhydride substituted with polyalkenyl. International patent application WO 2010/115594 ('594) and international patent application WO 2010/115595 (' 595) describe the use, in compositions of lubricating oil of marine tubular piston engines (TPEO) containing 50% in mass or more of a Group II base oil, of respective minor amounts of a calcium salicylate detergent and a carboxylic acid anhydride substituted with polyalkenyl. The data in them shows that the combination results in an improved asphaltene dispersion. EP-A-2644687 ('687) describes the use of a combination of defined calcium salicylates and polyalkenyl substituted carboxylic acid anhydrides defined in a TPEO lubricant comprising a greater amount of a lubricating oil containing 50% viscosity. by mass or more than one Group I base oil. This achieves a good dispersion of asphaltenes at lower levels and therefore cheaper soap.

The technique, however, does not deal with the influence of the anhydride succination ratio in such combinations on the problem of asphaltene precipitation such as at higher saturation levels in the oil of lubricating viscosity in a TPEO. It is claimed that component (B) in the examples of '594 is a PIBSA derived from a 950 number average molecular weight polyisobutene; Your suction ratio is not indicated.

Compendium of the invention

It has now surprisingly been found that, when a polyalkenyl carboxylic acid anhydride additive of defined succination ratio, preferably prepared by a specific process, is used in a TPEO that includes a hydroxybenzoate detergent additive, an improved control of the precipitation and deposition of asphaltenes on the motor surfaces, particularly when the oil of lubricating viscosity in the TPEO is high saturated oil. The anhydride additive increases the performance of the detergent additive.

Therefore, a first aspect of the invention is a lubricating oil composition for marine tubular piston engines to improve the handling of asphaltenes in the use thereof, in the operation of such an engine when it is fed by a heavy fuel oil, composition which comprises, or is prepared by mixing, a greater amount of an oil of lubricating viscosity and, is respective minor amounts:

(A) a detergent hydroxybenzoate system substituted with super-alkali metal hydrocarbyl, and

(B) a hydrocarbyl-substituted succinic acid anhydride, preferably prepared using halogen or radical-assisted functionalization procedures, where the ratio of succinic anhydrous groups to substituted hydrocarbyl moiety is in the range of 1.4 to 4;

wherein the anhydride (B) constitutes at least 0.1 to 10% by mass, based on the active ingredient, of the lubricating oil composition.

A second aspect of the invention is a method for preparing a lubricating oil composition of marine tubular piston engines for a medium speed compression marine ignition engine, comprising

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Mix (A) and (B) with the oil of lubricating viscosity, each defined as in the first aspect of the invention.

A third aspect of the invention is a lubricating oil composition of marine tubular piston engines for a medium-speed marine compression ignition engine obtainable by the method of the second aspect of the invention.

A fourth aspect of the invention is a method of operating a marine compression ignition engine with a medium speed compression of a tubular piston, comprising:

(i) feed the engine with a heavy fuel oil; Y

(ii) lubricate the engine with a composition as defined in the first aspect of the invention.

A fifth aspect of the invention is a method for dispersing asphaltenes in the composition of tubular piston marine engine lubricating oil during its lubrication of the surfaces of a marine ignition engine by medium speed compression and engine operation, comprising:

(i) provide a composition as defined in the first aspect of the invention;

(ii) provide the composition to the engine;

(iii) provide heavy fuel oil to the engine; Y

(iv) produce the combustion of fuel oil.

A sixth aspect of the invention is the use of the detergent system (A) as defined in the first aspect of the invention in combination with the anhydride (B) as defined in the first aspect of the invention in a

Tubing piston marine engine lubricating oil composition for a marine ignition engine by

medium speed compression, to improve the handling of asphaltenes during engine operation that is powered by a heavy fuel oil.

A seventh aspect of the invention is the use of the detergent system (A) as defined in the first aspect of the invention in combination with the anhydride (B) as defined in the first aspect of the invention in a

Tubing piston marine engine lubricating oil composition for a marine ignition engine by

medium speed compression, to improve the handling of asphaltenes during engine operation, fed by a heavy fuel oil, compared to an analogous operation where the anhydride (B) has a different relationship from that defined in the first aspect of the invention .

In this specification, the following words and expressions, if and when used, have the meanings assigned below:

"Suction ratio" in relation to component (B) means the number of groups derived from sucrose anhydride for each substituted hydrocarbyl moiety. "Succmic relationship" or "succination ratio" refers to the ratio calculated in accordance with the procedure and mathematical equation set forth in columns 5 and 6 of US Pat. No. 5,334,321. It is claimed that the calculation represents the average number of succinic groups in an alkenyl- or alkylsuccinic anhydride per alkenyl chain or substituted alkyl.

"Active ingredients" or "(a.i.)" refers to additive material that is not diluent, solvent or unreacted hydrocarbyl moiety;

"Comprising" or any similar word specifies the presence of features, stages or whole numbers or components listed, but does not exclude the presence or addition of one or more other features, stages, whole numbers or components or groups thereof; the terms "consists of" or "consists essentially of" or the like may be encompassed within "comprises" or the like, wherein "consists essentially of" allows the inclusion of substances that do not materially affect the characteristics of the composition to which it applies;

"Greater amount" means 50 or more, preferably 60 or more, more preferably 70 or more, and even more preferably 80 or more, mass% of a composition;

"Lesser amount" means less than 50, preferably less than 40, even more preferably less than 30 and most preferably less than 20, mass% of a composition;

"TBN" means total base number, measured by ASTM D2896;

In addition, in this specification:

"Calcium content" is as measured by ASTM 4951;

"Phosphorus content" is as measured by ASTM D5185;

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"Sulfated ash content" is as measured by ASTM D874;

"Sulfur content" is as measured by ASTM D2622;

"KV100" means kinematic viscosity at 100 ° C, measured by ASTM D445.

Also, it will be understood that the various components used, essential, as well as optimal and customary, may react under conditions of formulation, storage or use, and that the invention also provides the product obtainable or obtained as a result of any such reaction.

In addition, it will be understood that any limits of upper and lower quantity, range and ratio set forth herein may be combined independently.

Detailed description of the invention

The features of the invention in its various aspects, if they are and where applicable, will now be discussed in more detail below.

Lubricating viscosity oil

Lubricating oils can vary in viscosity from mineral oils from light distillates to heavy lubricating oils. In general, the viscosity of the oil varies from 2 to 40 mm2 / s, measured at 100 ° C.

Natural oils include animal oils and vegetable oils (eg, castor oil, lard oil); liquid petroleum oils and hydro-refined oils, treated with solvents or treated with acids of the paraffinic, naphthenic and paraffinic-naphthenic mixed types. Oils of lubricating viscosity derived from carbon or shale also serve as useful base oils.

Synthetic lubricating oils include hydrocarbon oils and halosubstituted hydrocarbon oils, such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, copolymers of propylene-isobutylene, chlorinated polybutylenes, poly (l-hexenes), poly (l- octenos), poly (l-decene)); alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di (2-ethylhexyl) benzenes; polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenols); alkylated naphthalenes; and alkylated diphenyl ethers and diphenyl sulphides and sulfides of diphenyl derivatives, analogs and homologs thereof.

The polymers and interpolymers of alkylene oxides and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic lubricating oils. These are illustrated by polyoxyalkylene polymers prepared by polymerization of ethylene oxide or propylene oxide, and the alkyl and propyl ethers of polyoxyalkylene polymers (eg, methyl polypropylene glycol ether having a molecular weight of I .0O0, or diphenyl ether of polyethylene glycol, which has a molecular weight of 1,000 to 1,500); and mono- and polycarboxylic esters thereof, for example, esters of acetic acid, mixed esters of C3-C8 fatty acids and C13 oxo acid diester of tetraethylene glycol.

Another suitable class of synthetic lubricating oils comprises the esters of dicarboxylic acids (eg, phthalic acid, succmic acid, alkylsuccmic acids and alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebasic acid, smoking acid, adipic acid, dimer) of linoleic acid, malonic acid, alkylmalonic acids, alkenylmalonic acids) with various alcohols (e.g., butyl alcohol, hexyl alcohol, dodedyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of such esters include dibutyl adipate, di (2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisoctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, sebaca debacus dieicosyl, the 2-ethylhexyl diester of linoleic acid dimer, and the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid.

Useful esters such as synthetic oils also include those prepared from C5 to C12 monocarboxylic acids and polyol and polyol esters such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.

Silicone-based oils, such as polyalkyl-, polyaryl-, polyalkoxy- or polyaryloxysilicone oils, and silicate oils comprise another useful class of synthetic lubricants; such oils include tetraethyl silicate, tetraisopropyl silicate, tetra- (2-ethylhexyl) silicate, tetra- (4-methyl-2-ethylhexyl) silicate, tetra- (p-tert-butyl-phenyl) silicate, hexa - (4-methyl-2-ethylhexyl) disiloxane, poly (methyl) siloxanes and poly (methylphenyl) siloxanes. Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (eg, tricresyl phosphate, trioctyl phosphate, diethyl ester of decylphosphonic acid) and polymeric tetrahydrofurans.

Unrefined, refined and re-refined oils may be used in the lubricants of the present invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retort distillation operations; petroleum oil obtained directly from distillation; or ester oil obtained directly from an esterification and used without further treatment senna unrefined oil. Refined oils are similar to non-oils

refined, except that the oil is further treated in one or more stages of purification to improve one or more properties. Many such purification techniques, such as distillation, solvent extraction, acid or base extraction, filtration and percolation are known to those skilled in the art. Refined oils are obtained by procedures similar to those used to provide refined oils, but start with oil that has already been used in service. Such re-refined oils are also known as regenerated or reprocessed oils, and are often subjected to further processing using techniques to remove spent additives and oil breakage products.

The publication of the American Petroleum Institute (API) "Engine Oil Licensing and Certification System", Industry Services Department, Fourteenth Edition, December 1996, Appendix 1, December 1998, classifies 10 base oils as follows:

a) Group I base oils, contain less than 90 percent saturated and / or more than 0.03 percent sulfur and have a viscosity index greater than or equal to 80 and less than 120 using the specified test methods in Table E-1.

b) Group II base oils, contain more than or equal to 90 percent saturated and less than or equal to 0.03 per 15 percent sulfur and have a viscosity index greater than or equal to 80 and less than 120 using the methods of

test specified in Table E-1.

c) Group III base oils, contain more than or equal to 90 percent saturated and less than or equal to 0.03 percent sulfur and have a viscosity index greater than or equal to 120 using the specified test methods in Table E-1.

20 d) Group IV base oils are polyalphaolefins (PAO).

e) Group V base oils, include all other base oils not included in Group I, II, III or IV.

The analytical methods for the Base Oil are tabulated below (Table E-1):

 PROPERTY

 TESTING METHOD

 Saturated

 ASTM D 2007

 viscosity index

 ASTM D 2270

 Sulfur

 ASTM D 2622

 ASTM D 4294

 ASTM D 4927

 ASTM D 3120

The present invention particularly encompasses those of the above oils that contain more than or equal to 25 90% saturated and less than or equal to 0.03% sulfur as an oil of lubricating viscosity, eg Group II, III,

IV or V. They also include base lubricating oils derived from hydrocarbons synthesized by the Fischer-Tropsch process. In the Fischer-Tropsch process, synthesis gas is first generated containing carbon monoxide and hydrogen (or "syngas") and then converted into hydrocarbons using a Fischer-Tropsch catalyst. These hydrocarbons typically require additional processing to be useful as a base oil. For example, they can be, by methods known in the art, hydroisomerized; hydrocracked and hydroisomerized; descended; or hydroisomerized and lowered. The syngas can be prepared, for example, from gas such as natural gas or other gaseous hydrocarbons by steam reforming, where the base oil may be referred to as a gas-to-liquid base oil ("GTL"); or from biomass gasification, when the base oil may be referred to as liquid biomass base oil ("BTL" or "BMTL"); or from carbon gasification, where the base oil may be referred to as liquid carbon base oil ("CTL").

Preferably, the lubricating viscosity oil in this invention contains 30, such as 50,% by mass or more of said base oils. It may contain 60, such as 70, 80 or 90,% by mass or more of said base oils or a mixture thereof. The lubricating viscosity oil may be substantially all of said base oils or a mixture thereof.

It may be desirable, although not essential, to prepare one or more packages of additives or concentrates comprising additives, whereby additives (A) and (B) can be added simultaneously to the oil of lubricating viscosity to form the TPEO.

Final formulations such as tubular piston engine oil can typically contain up to 30,

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preferably 10 to 28, more preferably 12 to 24,% by mass of the additive package (s), the remainder being the oil of lubricating viscosity. The tubular piston engine oil can have a compositional TBN (using ASTM D2896) of 20 to 60, preferably 30 to 55. Even more preferably, it can be 40 to 55 or 35 to 50.

The combined treatment rate of the additives (A) and (B) contained in the lubricating oil composition may be for example in the range of 5 to 30, preferably 10 to 28, more preferably 12 to 24,% by mass.

Super-alkaline metal detergent additive (A)

A metallic detergent is an additive based on the so-called metal "soaps", that is, metal salts of acidic organic compounds, sometimes referred to as surfactants. They generally comprise a polar head with a long hydrophobic tail. Over-alkalized metal detergents, which comprise neutralized metal detergents as the outer layer of a micelle of a metal base (eg carbonate), can be provided including large amounts of metal base by reacting an excess of a metal base, such as an oxide or hydroxide, with an acid gas such as carbon dioxide.

In the present invention, the over-alkalized metal detergents (A) are over-alkali metal detergents of hydrocarbyl-substituted hydroxybenzoate, preferably hydrocarbyl-substituted salicylate.

"Hydrocarbyl" means a group or radical that contains carbon and hydrogen atoms and that is attached to the rest of the molecule by means of a carbon atom. It may contain heteroatoms, that is, atoms other than carbon and hydrogen, provided that they do not alter the essentially hydrocarbon nature and characteristics of the group. As examples of hydrocarbyl, alkyl and alkenyl can be mentioned. Hydroxybenzoate substituted with super-alkali metal hydrocarbyl typically has the structure shown:

image 1

wherein R is a linear or branched aliphatic hydrocarbyl group, and more preferably an alkyl group, including straight or branched chain alkyl groups. There may be more than one R group attached to the benzene ring. M is an alkali metal (eg lithium, sodium or potassium) or an alkaline earth metal (eg calcium, magnesium, barium or strontium). Calcium or magnesium is preferred; calcium is especially preferred. The COOM group may be in the ortho, meta or para position with respect to the hydroxyl group; ortho position is preferred. The R group may be in the ortho, meta or para position with respect to the hydroxyl group. When M is polyvalent, it is represented fractionally in the above formula.

Hydroxybenzoic acids are typically prepared by carboxylation, by the method of Kolbe-Schmitt, of phenoxides, and in that case, they will generally be obtained (usually in a diluent) in admixture with non-carboxylated phenol. Hydroxybenzoic acids can be non-sulphured or sulfurized, and can be chemically modified and / or contain additional substituents. Methods for sulfurizing a hydrocarbon-substituted hydroxybenzoic acid are well known to those skilled in the art, and are described, for example, in US 2007/0027057.

In hydrocarbyl-substituted hydroxybenzoic acids, the hydrocarbyl group is preferably alkyl (including straight or branched chain alkyl groups), and the alkyl groups advantageously contain 5 to 100, preferably 9 to 30, especially 14 to 24, carbon atoms.

The term "over-alkalized" is generally used to describe metal detergents in which the ratio of the number of equivalents of the metal moiety to the number of equivalents of the acid moiety is greater than one. The term "low alkalization" is used to describe metal detergents in which the ratio of equivalents of the metal moiety to the acid moiety is greater than 1, and up to about 2.

By a "calcium salt over-alkalinized surfactants" is meant an alkaline detergent in which the metal cations of the metal salt insoluble in oil are essentially calcium cations. Small amounts of other cations may be present in the oil-insoluble metal salt, but typically at least 80, more typically at least 90, for example at least 95 mol% of the cations in the oil-insoluble metal salt are ions of calcium. Cations other than calcium may, for example, come from the use in the manufacture of the super-alkaline detergent of a surfactant salt in which the cation is a metal other than calcium. Preferably, the metal salt of the surfactant is also calcium.

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Carbonated super-alkaline metal detergents typically comprise amorphous nanoparticles. Additionally, there are descriptions of nanoparticle materials comprising carbonate in the crystalline forms of calcite and vaterite.

The basicity of detergents can be expressed as total base number (TBN). A total base number is the amount of acid needed to neutralize all the basicity of the super-alkalized material. TBN can be measured using the ASTM D2896 standard or an equivalent procedure. The detergent can have a low TBN (i.e. a TBN less than 50), a medium TBN (i.e. a TBN of 50 to 150) or a high tBn (i.e. a TBN greater than 150, such as 150- 500). In this invention, the Basicity index is used. The Basicity index is the total base to total soap molar ratio in the super-alkaline detergent. The Detergent Basicity Index

(A) in the invention it is preferably in the range of 1 to 8, more preferably 3 to 8, such as 3 to 7, such as 3 to 6. The Basicity index may be for example greater than 3.

The over-alkali metal hydrocarbyl substituted hydroxybenzoates can be prepared by any of the techniques employed in the art. A general method is as follows:

1. Neutralization of hydroxybenzoic acid substituted with hydrocarbyl with a molar excess of metal base to produce a hydroxybenzoic complex substituted with slightly over-alkalized metal hydrocarbyl, in a solvent mixture consisting of a volatile hydrocarbon, an alcohol and water;

2. Carbonation to produce colloidal dispersed metal carbonate, followed by a post-reaction period;

3. Removal of residual solids that are not colloidally dispersed; Y

4. Purification to remove the solvents from the procedure.

The super-alkali metal hydrocarbyl substituted hydroxybenzoates can be prepared by a discontinuous or continuous super-alkalization process.

The metal base (eg metal hydroxide, metal oxide or metal alkoxide), preferably lime (calcium hydroxide), can be charged in one or more stages. The charges may be the same or they may differ, as can the carbon dioxide charges that follow them. When an additional calcium hydroxide charge is added, the carbon dioxide treatment of the previous stage does not need to be complete. As carbonation takes place, the dissolved hydroxide is converted into colloidal carbonate particles dispersed in the mixture of volatile hydrocarbon solvent and non-volatile hydrocarbon oil.

The carbonation can be carried out in one or more stages over a temperature range up to the reflux temperature of the alcohol promoters. The addition temperatures may be similar, or different, or may vary during each stage of addition. Phases in which temperatures rise, and optionally are reduced later, may precede additional carbonation stages.

The volatile hydrocarbon solvent of the reaction mixture is preferably a normally liquid aromatic hydrocarbon having a boiling point no greater than about 150 ° C. It has been found that aromatic hydrocarbons offer certain benefits, eg improved filtration rates, and examples of suitable solvents are toluene, xylene and ethylbenzene.

The alkanol is preferably methanol, although other alcohols such as ethanol can be used. The correct choice of the ratio of alkanol to hydrocarbon solvents, and the water content of the initial reaction mixture, are important to obtain the desired product.

Oil can be added to the reaction mixture; if so, suitable oils include hydrocarbon oils, particularly those of mineral origin. Oils that have viscosities of 15 to 30 mm2 / s at 38 ° C are very suitable.

After the final treatment with carbon dioxide, the reaction mixture is typically heated to an elevated temperature; eg above 130 ° C, to remove volatile materials (water and any remaining alkanol and hydrocarbon solvent). When the synthesis is complete, the crude product is cloudy, as a result of the presence of suspended sediments. It is clarified, for example, by filtration or centrifugation. These measurements can be used before, or at an intermediate point, or after solvent removal.

The products are used as diluent dispersion (or oil). If the reaction mixture contains insufficient oil to retain an oily solution after removal of the volatiles, additional oil must be added. This may occur before, or at an intermediate point, or after removal of the solvent.

Preferably, the diluent used for (A) comprises a base oil that contains more than or equal to 90% saturated and less than or equal to 0.03% sulfur. (A) may contain up to 20, 30, 40, 50, 60, 70, 80 or 90,% by mass or more (such as all) of said base oil. An example of said base oil is a Group II base oil.

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Anhydride of sucrose acid substituted with hydrocarbyl (B)

The anhydride may constitute at least 0.1 to 10, preferably 0.5 to 8.5, even more preferably 1 to 7, and most preferably 1.5 to 5,% by mass, based on the active ingredient, of the lubricating oil composition. Preferably it constitutes 2 to 5, more preferably 2.5 to 4, mass%.

The hydrocarbyl group is preferably a polyalkenyl group, and preferably has from 36 to 216, more preferably 56 to 108, carbon atoms. It can have a number average molecular weight in the range of 500 to 3,000; preferably 700 to 2,300; even more preferably 800 to 1,500.

The succination ratio is, as indicated, in the range of 1.4 to 4, preferably 1.4 to 3; more preferably it is in the range of 1.50 to 2.20, even more preferably 1.50 to 2.00, and most preferably 1.60 to 2.00.

Suitable hydrocarbons or polymers used in the formation of the anhydrides of the present invention to generate the polyalkenyl moieties include homopolymers, interpolymers or lower molecular weight hydrocarbons. A family of such polymers comprises polymers of ethylene and / or at least one C3 to C28 alpha-olefin having the formula H2C = CHR1, wherein R1 is a straight or branched chain alkyl radical comprising 1 to 26 carbon atoms and wherein the polymer contains carbon to carbon unsaturation, such as with a high degree of terminal ethenylidene unsaturation. Preferably, such polymers comprise interpolymers of ethylene and at least one alpha-olefin of the above formula, wherein R 1 is alkyl of 1 to 18 carbon atoms, and more preferably it is alkyl of 1 to 8 carbon atoms, and more preferably even 1 to 2 carbon atoms. Therefore, useful alpha-olefin monomers and comonomers include, for example, propylene, butene-1, hexene-1, octene-1, 4-methylpentene-1, decene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1, and mixtures thereof (eg, mixtures of propylene and butene-1, and the like). Illustrative of such polymers are propylene homopolymers, butene-1 homopolymers, ethylene-propylene copolymers, ethylene-butene-1 copolymers, propylene-butene copolymers and the like, wherein the polymer contains at least some terminal unsaturation and / or internal Unsaturated copolymers of ethylene and propylene and ethylene and butene-1 are possible polymers. The interpolymers may contain a smaller amount, eg 0.5 to 5 mol% of a C4 to C18 unconjugated diolefin comonomer. However, it is preferred that the polymers comprise only alpha-olefin homopolymers, alpha-olefin comonomer interpolymers and ethylene interpolymers and alpha-olefin comonomers. The ethylene molar content of the polymers used is preferably in the range of 0 to 80%, and more preferably 0 to 60%. When propylene and / or butene-1 is used as a comonomer (s) with ethylene, the ethylene content of such copolymers is most preferably between 15 and 50%, although higher or lower ethylene contents may be present.

These polymers can be prepared by polymerizing alpha-olefin monomer, or mixtures of alpha-olefin monomers, or mixtures comprising ethylene and at least one C3 to C28 alpha-olefin monomer, in the presence of a catalyst system comprising at least one metallocene (eg, a cyclopentadienyl-transition metal compound) and an alumoxane compound. Using this procedure, a polymer can be provided in which 95% or more of the polymer chains possess terminal ethenylidene unsaturation. The percentage of polymer chains that exhibit terminal ethenylidene unsaturation can be determined by FTIR spectroscopic analysis, titration, or C13 NMR. Interpolymers of this latter type can be characterized by the formula POLY-C (R1) = CH2, wherein R1 is C1 to C26 alkyl, preferably C1 to C18 alkyl, more preferably C1 to C8 alkyl, and most preferably C1 to C alkyl C2 (eg, methyl or ethyl) and where POLY represents the polymer chain. The chain length of the alkyl group R1 will vary depending on the comonomer (s) selected for use in the polymerization. A smaller amount of the polymer chains may contain terminal ethenyl unsaturation, that is, vinyl, that is, POLY-CH = CH2, and a portion of the polymers may contain internal monounsaturation, eg POLY-CH = CH ( R1), where R1 is as defined above. These terminal unsaturated interpolymers can be prepared by known metallocene chemistry, and can also be prepared as described in US Pat. Nos. 5,498,809; 5,663,130; 5,705,577; 5,814,715; 6,022,929 and 6,030,930.

Another useful class of polymer is polymers prepared by cationic polymerization of isobutene, styrene and the like. Typical polymers of this class include polyisobutenes obtained by polymerization of a stream of C4 refinne having a butene content of about 35 to about 75% by mass and an isobutene content of about 30 to about 60% by mass, in the presence of a Lewis acid catalyst, such as aluminum trichloride or boron trifluoride. A preferred source of monomer to prepare poly-n-butenes are oil feed streams such as Raffinate II. These raw materials are described in the art, as in the U.S. patent. No. 4,952,739. Polyisobutylene is a very preferred main chain of the present invention, because it is readily available by cationic polymerization of butene streams (eg, using AlCh or BF3 catalysts). Such polyisobutylenes generally contain residual unsaturation in amounts of approximately one ethylene double bond per polymer chain, positioned along the chain. One embodiment uses polyisobutylene prepared from a stream of pure isobutylene or a stream of Raffinate I to prepare isobutylene polymers reactive with terminal vinylidene olefins. These polymers, called highly reactive polyisobutylene (HR-PIB), can have a terminal vinylidene content of at least 65%. The preparation of such polymers is described, for example, in US Pat. No. 4,152,499. The HR-GDP is known, and the HR-GDP is available in the market under the names

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Registered Glissopal ™ (from BASF) and Ultravis ™ (from BP-Amoco).

The polyisobutylene polymers that can be used are generally based on a hydrocarbon chain of 400 to 3,000. The methods for preparing polyisobutylene are known. The polyisobutylene can be functionalized by halogenation (eg, chlorination), the thermal "eno" reaction, or by free radical grafting using a catalyst (eg peroxide), as described below.

To produce (B), the main chain of the hydrocarbon or polymer can be functionalized, with carboxylic antudride producing moieties selectively at the carbon-to-carbon unsaturation sites in the polymer chains

Or hydrocarbon, or randomly along the chains using one or more of the three procedures mentioned above or combinations thereof, in any sequence.

Methods for reacting polymer hydrocarbons with unsaturated carboxylic antudides and the preparation of derivatives of such compounds are described in US Pat. Nos. 3,087,936; 3,172,892; 3,215,707; 3,231,587; 3,272,746; 3,275,554; 3,381,022; 3,442,808; 3,565,804; 3,912,764; 4,110,349; 4,234,435; 5,777,025; 5,891,953; as well as EP 0 382 450 B1; CA-1,335,895 and GB-A-1,440,219. The polymer or hydrocarbon can be functionalized with carboxylic acid antidride moieties by reacting the polymer or hydrocarbon under conditions that result in the addition of functional moieties or agents, that is, acid, antidrug, on the chains of the polymer or hydrocarbon, mainly in carbon-to-carbon unsaturation sites (also called ethylenic or olefmic unsaturation) using halogen-assisted or radical-assisted functionalization procedures (eg, chlorination), such as chlorine or radical maleation.

The functionalization is preferably carried out by halogenating, for example, chlorinating or brominating, the unsaturated α-olefin polymer up to about 1 to 8% by mass, preferably 3 to 7% by mass of chlorine, or bromine, based on weight of the polymer or hydrocarbon, by passing the chlorine or bromine through the polymer at a temperature of 60 to 250 ° C, preferably 130 to 220 ° C, e.g., 140 to 190 ° C, for about 0.5 to 10, preferably

1 to 7 hours The halogenated polymer or hydrocarbon (hereinafter the main chain) is then reacted with sufficient monounsaturated reactant capable of adding the required number of functional residues to the main chain, e.g., monounsaturated carboxylic reactant, at 100 to 250 ° C, usually about 140 ° C to 220 ° C, for about 0.5 to 10, eg, 3 to 8 hours, such that the product obtained will contain the desired number of moles of the monounsaturated carboxylic reactant per mole of the chains main halogenated. Alternatively, the main chain and the monounsaturated carboxylic reactant are mixed and heated while chlorine is added to the hot material.

U.S. Pat. 4,234,435 (mentioned above) describes PIBSAs prepared by the chlorine route (Diels-Alder procedure). Its summary states “carboxylic acid acylation agents are derived from polyalkenes such as polybutenes, and a carboxylic, dibasic reactant, such as maleic or smoking acid or certain derivatives thereof. These acylating agents are characterized in that the polyalkenes from which they are derived have a value of Mn of about 1,300 to about 5,000 and a value of Mw / Mn of about 1.5 to about 4. The acylation agents are further characterized by the presence within its structure of at least 1.3 groups derived from carboxylic, dibasic reactant, for each equivalent weight of the groups derived from polyalkene. The acylating agents can be reacted with an additional reactant subject to acylation, such as polyamines and polyethylene polyols (eg, pentaerythritol) to produce useful derivatives of themselves as lubricant additives or as intermediate compounds to be subjected to post-treatment with various other chemical compounds and compositions, such as epoxides, to produce even other useful derivatives as lubricant additives. ”

Document CA 2,471,534 describes PIBSAs prepared by the reaction eno (which falls outside the present invention). Its summary refers to "a process for forming an eno reaction product wherein an enophyl, such as maleic anhydride, is reacted with reactive polyalkene having a terminal vinylidene content of at least 30 mol%, at high temperature in presence of a free radical inhibitor. Polyalkenyl acylating agents are useful in themselves as additives in lubricating oils, functional fluids and fuels, and they also serve as intermediates in the preparation of other products (eg, succinimides) useful as additives in lubricating oils, fluids Functional and combustible. The presence of the free radical inhibitor during the high temperature reaction results in a reaction product that is low in, or substantially free of, sediment. ”

It is believed that the Diels-Alder procedure produces a didactic union of two bonds of the succinic group to the polybutene. This is structurally quite sharp, and keeps the succinic group limited to an imide structure when reacted with a functionalizing agent such as a polyamine. On the other hand, a PIBSA of reaction eno (reaction of displacement of hydrogen 1.5) has a union by simple link between the succinic group and the polybutene, and as such it will allow the rotation and the opening of the succinic group (to dicarboxylic acid) to allow the formation of diamide in the correct conditions of energy (low temperature) and excess of amine.

The main chain of the hydrocarbon or polymer can be functionalized by random joining of the functional moieties along the chains of the polymer by various methods. For example, the polymer, in solution or in solid form, can be grafted with the monounsaturated carboxylic reactant, described above, in

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presence of a free radical initiator. When performed in solution, the graft takes place at an elevated temperature, in the range of about 100 to 260 ° C, preferably 120 to 140 ° C. Preferably, the free radical initiated graft will be carried out in a solution in lubricating mineral oil containing, for example, 1 to 50% by mass, preferably 5 to 30% by mass, of polymer based on the solution of total initial oil.

The free radical initiators that can be used are peroxides, hydroperoxides and azo compounds, preferably those with a boiling point greater than about 100 ° C and thermally decompose within the graft temperature range to provide free radicals. Azobutyronitrile, 2,5-dimethylhex-3-ene-2, tertiary 5-bis-butyl peroxide and dicumene peroxide are representative of these free radical initiators. The initiator, when used, is typically used in an amount of between 0.005% and 2% by weight based on the weight of the reaction mixture solution. Typically, the monounsaturated carboxylic reactant mentioned above and the free radical initiator are used in a weight ratio range of about 1.0: 1 to 30: 1, preferably 3: 1 to 6: 1. Grafting is preferably carried out in an inert atmosphere, such as under a blanket of nitrogen. The resulting grafted polymer is characterized by having carboxylic acid (or derivative) moieties randomly joined along the polymer chains: it being understood, of course, that some of the polymer chains remain ungrafted. The free radical grafting described above can be used for the other hydrocarbon polymers of the present invention.

To provide the required functionality, the monounsaturated carboxylic reactant, preferably maleic anhydride, will be used typically in an amount ranging from about the equimolar amount to about 100% excess mass, preferably 5 to 50% excess mass, based on moles of polymer or hydrocarbon. The unreacted excess monounsaturated carboxylic reactant can be removed from the final dispersant product, for example, by purification, usually under vacuum, if required.

Co-additives

The lubricating oil composition of the invention may further comprise additives, different from and additional to (A) and (B). Such additional additives may include, for example, ash-free dispersants, other metal detergents, antiwear agents such as zinc dihydrocarbyldithiophosphates, antioxidants and demulsifiers.

The following examples illustrate but in no way limit the invention.

Examples

Components

The following compounds were used:

Lubricating viscosity oil

A 600R API Group II base oil from Chevron

(A) Detergents (1) a Ca 225BN alkylsalicylate (alkyl = C14-18).

(2) a Ca 350BN alkylsalicylate (alkyl = C14-18).

(B) A set of polyisobutene sucrose anhydrides ("PIBSA") derived from a polyisobutene and prepared by a chloro- (Diels-Alder) process. The properties of each PIBSA are shown in the table in the Results section below.

(C) A 0.5% zinc dihydrocarbyldithiophosphate.

Heavy Fueloil 1S0-F-RMG 380

Lubricants

Selections of the above components were mixed with the oil of lubricating viscosity to give a range of tubular piston marine engine lubricants. Some of the lubricants were examples of the invention; others were reference examples for comparison purposes. Each lubricant contains the same combination of detergents in (A) to give a lubricating oil with a TBN of 40 mg KOH / g and a different PIBSA at a treatment rate of 2-6% by mass.

essays

Light scattering

The test lubricants were evaluated for asphaltene dispersion using light scattering according to the Focused Beam Reflectance Method ("FBRM"), which predicts the agglomeration of asphaltenes and therefore the formation of "black sludge".

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The FBRM test method was described in the 7th International Symposium on Marine Engineering, Tokyo, October 24-28, 2005, and was published in "The Benefits of Salicylate Detergents in TPEO Applications with a Variety of Base Stocks" at the Conference Proceedings Additional details were described at the CIMAC Congress, Vienna, May 21-24, 2007, and published in "Meeting the Challenge of New Base Fluids for the Lubrication of Medium Speed Marine Engines - An Additive Approach" at the Congress Proceedings. In this last document it is described that using the FBRM method it is possible to obtain quantitative results for the dispersion of asphaltenes that predict the performance for lubricating systems based on base oils that contain more than or less than 90% saturated, and more than or less than 0.03% sulfur. The relative performance predictions obtained from FBRM were confirmed by engine tests in marine diesel engines.

The FBRM probe contains fiber optic cables through which laser light travels until it reaches the tip of the probe. At the tip, an optical element focuses the laser light at a small point. The optical element is rotated so that the focused beam sweeps a circular path between the probe window and the sample. As the particles flow past the window, they intersect the scanning path, giving backscattered light from the individual particles.

The scanning laser light beam travels much faster than particles; This means that the particles are in practice stationary. As the focused beam reaches one edge of the particle, the amount of backscattered light increases; the amount will decrease when the focused beam reaches the other edge of the particle.

The instrument measures the time of increased backscatter. The period of backscattering of a particle is multiplied by the scanning speed, and the result is a distance or chord length. A chord length is a straight line between any two points on the edge of a particle. This is represented as a distribution of chord lengths, a graph of the numbers of chord lengths (particles) measured as a function of the dimensions of the chord length in micrometers. Since measurements are made in real time, the statistics of a distribution can be calculated and tracked. The FBRM typically measures tens of thousands of chords per second, resulting in a robust number distribution by length of chord. The method gives an absolute measure of the distribution of particle sizes of asphaltene particles.

The Focused Beam Reflectance Probe (FBRM), model Lasentec D600L, was supplied by Mettler Toledo, Leicester, United Kingdom. The instrument was used in a configuration to give a resolution of particle sizes from 1 pm to 1 mm. FBRM data can be presented in several ways. Studies have suggested that average counts per second can be used as a quantitative determination of asphaltene dispersion. This value is a function of both the average size and the agglomerate level. In this application, the average count rate (over the entire size range) was monitored using a measurement time of 1 second per sample.

The test lubricant formulations were heated to 60 ° C and stirred at 400 rpm. A heavy fuel oil alfcuot (16% by weight) was introduced into the lubricant formulation under agitation using a four-blade agitator (at 400 rpm) and at 60 ° C. This mixture was stirred overnight. With the temperature at 60 ° C, the FBRM probe was inserted into the sample. A value was taken for the average counts per second when the count rate had reached an equilibrium value (typically after 30 minutes of equilibration time).

Results

Response curves were generated showing the number of particle counts versus the treatment rate of the active ingredient of PIBSA. The results are presented as the treatment rate of the active ingredient required to deliver equivalent particle counts to a reference oil. Therefore, the low active ingredient treatment rate values indicate better performance.

In the table below, the properties shown (Suction Ratio and Mn) are of the PIBSA used in each of the test lubricants.

Table 1

 Examples

 Mating procedure Succination Ratio GDP Mn / g mol-1 Treatment rate of the active ingredient required to reach a normalized count = 1 /% by weight

 Comparative Example 1

 Chlorine 1.17 1,331 4.50

 Comparative Example 2

 Chlorine 1.19 950 4.93

 Comparative Example 3

 Chlorine 1.27 2.225 4.10

 Comparative Example 4

 Chlorine 1.31 1,600 4.70

 Example 1

 Chlorine 1.41 1,331 2.58

 Example 2

 Chlorine 1.62 1,331 3.10

 Example 3

 Chlorine 1.64 950 1.60

 Example 4

 Chlorine 1.88 950 1.70

 Example 5

 Chlorine 1.91 1,331 1.83

 Example 6

 Chlorine 2.06 950 2.09

 Example 7

 Chlorine 2.17 2,225 2.67

 Example 8

 Chlorine 2.20 2.225 2.44

 Example 9

 Chlorine 2.67 950 2.41

 Example 10

 Chlorine 3.10 1,331 2.01

 Example 11

 Chlorine 3.94 950 2.35

The table shows that much better results are achieved at higher suction ratios, that is, 1.41 to 3.94, as indicated below the bar. Although good results can be achieved at higher molecular weights of GDP (polyisobutylene), PIBSAs prepared therefrom have very high viscosities. Therefore, they have to be diluted much more than PIBSAs of lower molecular weight GDP. Therefore, PIBSAs of Mn of GDP 1,331 and 950 g mol-1 are preferred. Very high suction ratios or high polymer molecular weights lead to high viscosities; therefore, an Mn of GDP range of 700-1,500 g mol- and an RS (suction ratio) range of 1.50-2.00, preferably 1.70 or 1.65-2.00, are preferred.

The anhydride additives of the present invention have been shown to increase the yield of salicylates 10 to improve their dispersion of asphaltenes. Conventionally, dispersants of PIBSAPAM type are used to disperse contaminants in the lubricating oils. Therefore, a comparison was made with two such dispersants of type PIBSAPAM (see the table below). In combination with salicylates, it can be seen that dispersants of PIBSAPAM type cannot reach a yield equivalent to anhydride additives, which reach normalized counts of "1" (ie equivalent yield) at treatment rates of active ingredient much more. low.

 Example

 Description Rate of active ingredient treatment /% by weight Standardized discounts

 Comparative Example 5

 Low molecular weight, low RS, chlorine, dispersant of type PIBSAPAM 3 9.0

 Comparative Example 6

 High molecular weight, low RS, dispersant of type PIBSAPAM1 3.3 4.17

1 As described in US-A-3,219,666 (PIBSAPAM of low molecular weight) and US-A-6,127,321 (PIBSAPAM of high molecular weight).

The materials of the invention do not work in the absence of salicylate detergents to affect the dispersion of asphaltenes. In the table below, the two PIBSAs were tested in the absence of salicylates, and were unable to achieve an equivalent yield for any of the PIBSA / salicylate combinations of the present invention. Even at significantly increased treatment rates, no further improvements were observed.

 Example

 RS Material Active ingredient treatment /% by weight Standardized counts

 Comparative Example 7

 PIBSA of Example 4 1.18 3.58 6.4

 Comparative Example 8

 Example 2 1.62 3.78 7.16

In addition, the PIBSAs synthesized by a “thermal therma” strategy were ineffective compared to the PIBSAs of the present invention derived from a strategy of chlorination or radical maluation. These were tested in combination with salicylates.

 Example

 Procedure RS Mn of GDP / g mol-1 Treatment rate of active ingredient to reach a normalized count = 1 /% by weight

 Comparative Example 9

 Thermal 1.18 450 4.72

 Comparative Example 10

 Thermal 1.05 700 4.84

 Comparative Example 11

 Thermal 1.05 950 4.8

 Comparative Example 12

 Thermal 1.6 1,300 6.8

Claims (15)

5 10 fifteen twenty 25 30 35 40 Four. Five 1. A composition of lubricating oil for marine tubular piston engines, to improve the handling of asphaltenes in the use thereof, in the operation of such an engine when it is fed by a heavy fuel oil, composition comprising, or prepared by mixing , an oil of lubricating viscosity and, in respective minor amounts: (A) a detergent hydroxybenzoate system substituted with super-alkali metal hydrocarbyl, and (B) a hydrocarbyl-substituted succinic acid anhydride, preferably prepared using halogen or radical-assisted functionalization procedures, where the ratio of succinic anhydrous groups to substituted hydrocarbyl moiety is in the range of 1.4 to 4, preferably 1, 4 to 3; wherein the anhydride (B) constitutes at least 0.1 to 10% by mass, based on the active ingredient, of the lubricating oil composition. 2. The composition of claim 1, wherein, in (B), the hydrocarbyl group has a number average molecular weight in the range of 500 to 3,000. 3. The composition of claim 2, wherein the number average molecular weight is in the range of 700 to 2,300, preferably 800 to 1,500. 4. The composition of any one of claims 1 to 3, wherein, in (B), the ratio is in the range of 1.50 to 2.20, preferably 1.50 to 2.00, more preferably 1.60 to 2.00 5. The composition of any one of claims 1 to 4, wherein, in (B), the hydrocarbyl group is a polyalkenyl group, such as a polyisobutylene group. 6. The composition of any one of claims 1 to 5, wherein (B) is prepared by a chlorine maleation process. 7. The composition of any one of claims 1 to 6, wherein the lubricating viscosity oil comprises a Group II, III, IV or V base oil. 8. The composition of any one of claims 1 to 7, wherein the lubricating viscosity oil contains 30, such as 50,% by mass or more than a base oil containing more than or equal to 90% saturated and less than or equal to 0.03% sulfur or a mixture thereof. 9. The composition of any one of claims 1 to 8, which has a TBN in the range of 20 to 60, such as 30 to 55. 10. The composition of any one of claims 1 to 9, wherein the detergent system (A) comprises a calcium alkylsalicylate detergent system. 11. The composition of any one of the preceding claims, wherein the anhydride (B) constitutes at least 0.5 to 8.5, more preferably 1 to 7, and most preferably 1.5 to 5, mass%, based on the active ingredient, of the lubricating oil composition. 12. A method for operating a medium speed compression marine ignition engine, comprising: (i) feed the engine with a heavy fuel oil; Y (ii) lubricate the engine with a composition as defined in any one of claims 1 to 11. 13. A method for dispersing asphaltenes in the lubricating oil composition for marine tubular piston engines during their lubrication of the surfaces of a medium-speed marine ignition engine and engine operation, comprising: (i) providing a composition as defined in any one of claims 1 to 11; (ii) provide the composition to the engine; (iii) provide heavy fuel oil to the engine; Y (iv) produce the combustion of fuel oil. 14. The use of the detergent system (A) as defined in claim 1 in combination with the anhydride (B) as defined in claim 1 in a lubricating oil composition of marine tubular piston engines for a marine ignition engine by medium speed compression, to improve the handling of asphaltenes during Engine operation, powered by heavy fuel oil. 15. A concentrate suitable for mixing in a composition of any of claims 1 to 9, comprising (A) and (B) as defined in any of claims 1 to 6 and 10.