EP0404650A1 - Overbased lubricating oil additives containing a molybdenun complex, process of preparation and compositions containing the same - Google Patents

Abstract

Overbased additives for lubricating oils, containing an organic molybdenum complex which is practically insoluble in hydrocarbons. The complexes are formed with organic compounds such as amines, diamines, alkoxylated amines, glycols and polyols. <??>The additives according to the invention exhibit antiwear, friction reducing and antioxidant properties in lubricant formulations.

Description

This invention relates to overbased additives for lubricating oils containing an organic complex of molybdenum practically insoluble in hydrocarbons.

Overbased additives are alkali or alkaline earth metal salts of organic acids, overbased by carbonation with carbon dioxide. The term overbased is used to designate the excess of alkali or alkaline earth metal over the stoichiometric amount necessary to neutralize the organic acid used.

The structure of the overbased additives is that of a colloidal dispersion, the micelles of which contain the alkali or alkaline earth metal carbonate formed during carbonation. The micelles are stabilized by the alkali or alkaline earth metal salts of organic acids which have a detergent effect.

The salts of organic acids used in overbased additives are generally sulfonates, salicylates or sulfurized phenates, described respectively in US Patents 4,604,219, EP-A 279,493 and FR 2,305,494.

These overbased additives are particularly useful in lubricants used in internal combustion engines of the "gasoline" type or of the "diesel" type.

Thanks to their detergent and dispersant effect, they prevent the formation of lacquers and varnishes and keep soot in dispersion from the incomplete combustion of the fuel.

Another important function of these additives is the neutralization of acidic compounds, such as organic acids formed by oxidation of the oil and the acids formed during the combustion of sulfur products supplied by fuels.

This neutralization function is particularly appreciated when using fuels rich in sulfur, such as heavy fuels used in marine engines.

It is also known to use molybdenum additives in lubricants as friction reducers. The most anciently used product is molybdenum disulphide in the form of a stable dispersion.

To avoid the operations of grinding and stable dispersing of molybdenum disulphide, it has been proposed to use oil-soluble organic compounds of molybdenum, which can be incorporated directly into lubricants.

Among the oil-soluble compounds of molybdenum there may be mentioned the dithiocarbamates (EP-A 205 165), and the complexes of molybdenum with oxazoline (US 4,176,073). Molybdenum complexes with compounds containing basic nitrogen from succinimides, amides, phosphonamides or Mannich bases are used in sulfurized form (US 4,263,152, US 4,369,119, US 4,395,343).

Molybdenum overbased additives are also known. The molybdenum is incorporated in the form of an inorganic compound, during (US 4,601,837) or after (US 3,496,105) overbasing.

We have now unexpectedly found that it is possible to incorporate into overbased additives derivatives of molybdenum practically insoluble in hydrocarbons, since these derivatives dissolve during the overbasing reaction.

We do not want to be limited by this explanation hand we suggest that the molybdenum derivative is incorporated into the micelles of the colloidal dispersion with the alkali or alkaline earth metal carbonate.

The incorporation of the molybdenum derivative into the micelle results in the formation of a single multifunctional additive, having the properties of overbased additives and those of molybdenum derivatives. The advantage of this multifunctional additive compared to mixtures of overbased detergents and oil-soluble derivatives of molybdenum, lies in their greater stability and the fact that there is no competition between the two additives for access to the metal surface to be lubricated.

The additives according to the invention have antiwear, friction reducing and antioxidant properties in lubricant formulations.

This invention therefore relates to overbased additives for lubricating oils, composed of at least one detergent and of an alkali or alkaline earth metal carbonate in a diluent oil, characterized in that they contain at least one organic complex of molybdenum practically insoluble in hydrocarbons.

Among the organic molybdenum complexes, the amine-molybdenum complexes are particularly suitable.

The amine-molybdenum complexes are prepared by the reaction of an inorganic molybdenum compound with an acid reaction, with an amine.

Among these molybdenum compounds one can list molybdic acid, alkaline molybdates, sodium hydrogen molybdate, ammonium molybdate, MoOCl₄, MoO₂ Br₂, Mo₂O₃Cl₆ and molybdenum trioxide.

Sodium molybdate and ammonium molybdate are preferably used.

The amines used have an aliphatic or aromatic structure.

Among the aliphatic amines, primary, secondary or tertiary amines are suitable provided that they form complexes with molybdenum complexes which are practically insoluble in hydrocarbons. The use of primary amines, whose complexes with molybdenum are very poorly soluble in hydrocarbons is particularly recommended.

Among the primary amines we will cite oleylamine, stearylamine, dodecylamine, ter-dodecylamine, ethyl-2-hexylamine and cyclohexylamine.

The amine group can be attached to a primary carbon, as in the aforementioned amines, but also to a secondary or tertiary carbon, as in 1-amino-1,1-dimethyl-decane and 1-amino-1,1 -dimethyl-dodecane.

The use of certain secondary amines may be recommended. Thus secondary amines, in which the total number of carbon does not exceed 12, generally give, with molybdenum, complexes insoluble in hydrocarbons.

Among the aromatic amines we can mention para-dodecylaniline.

The use of diamines having a primary amine group is also recommended.

The diamines of the general formula R₁R₂N- (CH₂) _n -NH₂ (I) where R₁ and R₂ identical or different represent hydrogen or a linear or branched aliphatic radical, saturated or unsaturated in C₁ to C₃₀ and preferably in C₈ to C₂₀ , one of the radicals R₁ or R₂ necessarily representing an aliphatic radical and n being between 1 and 8 and preferably between 2 and 4, form complexes which are hardly soluble in hydrocarbons.

Some of the diamines of general formula (I) are sold by the company CECA S.A. under the name of DINORAM.

In the DINORAM series, R₁ represents hydrogen and R₂ represents saturated or unsaturated aliphatic radicals derived from fatty acids. They are generally mixtures containing C₁₂ to C₁₈ alkyl radicals.

The amine-molybdenum complex is generally prepared in an aqueous medium. The amine is added to an aqueous solution of mineral molybdenum compound.

The reaction medium is maintained at a temperature between 20 and 100 ° C, preferably between 50 and 90 ° C, for 0.5 to 3 hours after the addition of the amine.

The amount of acid necessary for neutralizing the reaction medium is added before or after the introduction of the amine. A strong mineral acid is used, preferably sulfuric acid.

The amine-molybdenum complex precipitates. It is recovered by filtration, washed with water and optionally dried.

The complex has a solid or pasty appearance, depending on the type of amine used. Its color varies from white to blue. It is practically insoluble or very slightly soluble in hydrocarbons.

The atomic ratio of nitrogen to molybdenum in the complex is generally between 0.25 and 4 and preferably between 0.5 and 2.

The molybdenum content of the complex varies depending on the nature of the amine used: it is between approximately 10 and 45%.

Among the organic molydene complexes, mention may also be made of complexes with oxygenated compounds.

Particularly suitable are glycols 1-2, 1-3 and 1-4. Preferably ethylene glycol and propylene glycol are used.

Among the polyols we can mention glycerol and trimethylol propane.

Certain amines, or alkoxylated polyamines, preferably with ethylene oxide or propylene oxide are also suitable. We can mention the derivatives of diethanolamine or tri-ethanolamine.

The preparation of these complexes can be carried out by heating the oxygenated compound to 90-100 ° C., in the presence of a molybdenum compound, such as ammonium molybdate. The water produced by the reaction is removed under a stream of nitrogen.

The molybdenum content of the complexes obtained varies between 7 and 50% by weight, depending on the degree of elimination of the unreacted oxygenated compound.

The organic molybdenum complex can be sulfurized, for example, by the action of sulfuric anhydride (H₂S) on a suspension of the complex in an aromatic solvent such as xylene or toluene, at a temperature between 40 ° C and 100 ° C. As soon as sulfuric anhydride is introduced, the color of the suspension changes from blue-green to orange and then to red. The quantity of sulfuric anhydride introduced is such that the atomic ratio of sulfur to molybdenum is between approximately 1 and 3.

The process for the preparation of overbased additives according to the invention consists in carbonating a mixture containing a detergent or a detergent precursor, an alkali or alkaline earth metal derivative, a nitrogenous and / or oxygenated promoter, optionally a hydrocarbon solvent, a diluent oil and / or water, characterized in that said mixture contains at least one organic complex of molybdenum practically insoluble in hydrocarbons.

Among the detergents which can be used in the context of the invention, there may be mentioned sulfonates, phenates, naphtenates, salicylates, phosphonates and thiophosphonates alkali or alkaline earth soluble in the hydrocarbon medium.

The sulfonic acids used for the preparation of the sulfonates can be of petroleum or synthetic origin. Petroleum sulfonic acids are prepared by sulfonation of oils from the distillation of petroleum. Their structure does not correspond to a well defined formula but their average molecular weight must be at least equal to 300.

Synthetic sulfonic acids are prepared by alkylation of aromatic compounds such as benzene, toluene, xylene or naphthalene with olefinic cuts and then by sulfonation of the alkylate obtained. The structure of the alkyl chains attached to the nucleus is linear or branched depending on the olefins used for the alkylation. The number of carbon atoms per alkyl chain is greater than or equal to 8.

The preparation of the alkali or alkaline earth metal sulfonate is carried out by bringing the sulfonic acid into contact with an alkali or alkaline earth metal derivative (preferably oxide or hydroxide) in a hydrocarbon solvent, optionally in the presence of an alcohol.

The alkali or alkaline earth metal phenates are prepared under analogous or substantially different conditions with respect to temperature, from alkylphenol or sulfurized alkylphenol. The phenol ring can carry one or two linear or branched alkyl chains, having at least eight carbon atoms. The most common compound is dodecylphenol.

The optional sulfurization of phenol is carried out by the action of sulfur monochloride S₂ Cl₂ or by the action of elemental sulfur at temperatures ranging from 150 to 200 ° C. The sulfurized product contains about 1 to 1.5 sulfur atoms per phenolic nucleus.

The alkylsalicylic acids are prepared by alkylation of salicylic acid or by carboxylation under pressure of alkylphenols. The alkyl chain contains a minimum of 12 carbon atoms.

The phosphonates and thiophosphonates are prepared by the action of P₂O₅ or P₂S₅ on a polyisobutene then neutralization with an alkali or alkaline earth oxide or hydroxide. The molecular weight of polyisobutene is between 300 and 2000.

All of these detergents can be used in admixture with dispersants soluble in a hydrocarbon medium, for example of the alkylsuccinimide type or esters of alkylsuccinic acids with a molecular weight of 300 to 2500.

Instead of detergents, the reaction medium can contain the precursors. In this case, neutralization is carried out in the reaction medium just before carbonation.

The alkali or alkaline earth metal derivatives can be oxides, hydroxides or alcoholates. The preferred derivatives are oxides and hydroxides.

These are added to the reaction medium in stoichiometric excess relative to the detergent or its precursor. The stoichiometric excess can vary between 5: 1 and 30: 1.

In the process according to the invention, an oxygenated promoter is introduced into the reaction medium before carbonation, which is generally an aliphatic or aromatic alcohol, an alkoxyalkanol, a glycol or even an alkanolamine. Preferably used aliphatic alcohols C₁ to C₂₀ or mixtures thereof. The aliphatic alcohols can be used in admixture with glycols, alkoxyalkanols or alkanolamines.

The molar ratio of the oxygenated promoter to the detergent is generally between 1 and 30.

The use of a nitrogenous promoter is optional. This nitrogenous promoter is generally chosen from ammonia, ammonium salts, primary, secondary or tertiary amines in C₂ to C₁₀ and their salts with carboxylic acids or boric acid, polyamines or even alkanolamines.

Among the nitrogenous promoters, ammonia, carbonate and ammonium chloride, ethylenediamine, ethanolamine or diethanolamine are preferred.

The promoter to detergent molar ratio is generally between 1 and 30.

The hydrocarbon solvent allows perfect homogenization of the various reagents as well as a lowering of the viscosity which will subsequently facilitate the recovery of solid carbonation residues. The solvent represents from 10 to 70% by weight of the reaction mixture. The solvents used are the aliphatic or aromatic compounds in C₆ and C₁₂. Preferred solvents are aromatic solvents such as benzene, toluene, xylene, ethylbenzene and chlorinated aromatics. Their choice is dictated by the characteristics of the additive collected, by their boiling point and by the boiling point of the azeotropes which they can form with oxygenated promoters and water.

The handling of the molybdenum overbased additive obtained according to the invention is facilitated by the addition of oil. The oil represents approximately 20 to 50% by weight of the additive obtained. This can be added to the reaction medium before carbonation or even after this, that is to say just before the removal of the solvent. The diluent oils used are paraffinic in nature, of the 100 or 150 Neutral solvent type or predominantly naphthenic in nature such as 100 - 150 pale solvent.

The carbonation reaction can be carried out after optional addition of water to the reaction medium. The addition of water is particularly beneficial when the alkali or alkaline earth metal derivative is an oxide. Generally the amount of water added is such that the water / metal oxide molar ratio is of the order of 0.5.

The implementation of the method according to the invention consists in successively introducing into a reactor equipped with an agitator, a temperature control, a device for bubbling carbon dioxide, a heating and heating system. empty:
- 0 to 700 parts by weight of a hydrocarbon solvent
- 100 to 400 parts by weight of a detergent or a detergent precursor
- an alkali or alkaline earth metal derivative in stoichiometric excess relative to the detergent or its precursor. This stoichiometric excess is between 5: 1 and 30: 1
- an oxygenated promoter whose molar ratio to the detergent or to its precursor is between 1 and 30
- optionally a nitrogenous promoter whose molar ratio to detergent is between 1 and 30
- optionally an amount of water such that the water / metal oxide molar ratio is of the order of 0.5
- optionally diluent oil in quantity such that it represents 20 to 50% by weight of the additive recovered at the end of the operations
- An organic complex of molybdenum described above in an amount such that the molybdenum content of the finished product is between 0.1 and 10% by weight.

In the case where a detergent precursor is used, it is preferable to successively introduce the precursor, the molybdenum complex and finally the excess of alkali or alkaline earth metal derivative.

Neutralization of the detergent precursor is then carried out, followed by carbonation of the stoichiometric excess of the alkali or alkaline earth metal derivative at a temperature between room temperature and the reflux temperature of the mixture. The molar ratio of CO₂ introduced to the stoichiometric excess of alkali or alkaline earth metal is between 0.6 and 1.2. The mixture is optionally stabilized by heating under vacuum or under a stream of nitrogen so as to eliminate the oxygenated promoters of low boiling point and the water added as well as the water produced by carbonation. Solid residues are removed by centrifugation and / or filtration using diatomaceous earth. If the diluent oil has not been added before carbonation, it is then added before possible elimination of the hydrocarbon solvent and heavy alcohols, by heating under vacuum at temperatures of the order of 100 to 200 ° C.

It should be noted that the filtration operation can be carried out after recovery of the solvent.

The overbased products containing molybdenum, obtained according to the invention, are clear and stable, brown in color for the sulfonates, dark green for the phenates and black for the salicylates. The color is generally red for overbased detergents in the presence of a sulfurized complex.

The rate of incorporation of molybdenum into the additive is close to 100%, significantly higher than the rates obtained during the incorporation of inorganic derivatives of molybdenum.

The additive contains between 0.1 to 10% by weight and preferably 1 to 4% of molybdenum.

The overbased additives according to the invention are entirely soluble in hydrocarbons. They are incorporated into lubricating oils of natural or synthetic origin at a concentration of between 0.5 and 40% by weight and preferably between 1 and 30% by weight.

The lubricant compositions thus obtained may contain other additives, with antiwear, dispersing, antioxidant effect, and polymers improving the viscosity index.

The examples below illustrate the invention without, however, limiting it.

In the examples, the basicity of these overbased additives is characterized by their alkaline value (VA) expressed in mg of KOH per gram of product. It is determined by titration using a strong acid according to standard ASTM D-2896.

Unless otherwise indicated, all percentages are by weight.

EXAMPLE A: Dinoram C / Molybdenum Complex

In a reactor fitted with a temperature control and a stirring device, a solution of 41.17 g of sodium molybdate Na₂MoO₄, 2H₂O in 100 ml of water is produced. The medium is acidified by addition of 55.6 g of 30% H₂SO₂ and then heated to 60 ° C. Next, 21g Dinoram C from CECA SA is added.
Dinoram C corresponds to the formula R-NH- (CH₂) ₃-NH₂ where R is a mixture of linear and saturated alkyl radicals, 60% C de, 20% C₁₄, 10% C₁₆ and 5% C₁₈.
The above-mentioned blue is recovered by filtration and then washed with water and methanol before drying.
Finally recovered 47.1 g of blue solid containing 32.6% molybdenum and 4.4% nitrogen.

EXAMPLE B: Dinoram C / Molybdenum Complex

The procedure is as in Example A but the addition of Diroram C is carried out at 60 ° C before heating and before acidification.
The pale blue solid recovered contains 34.1% molybdenum, 0.3% sodium and 4.46% nitrogen.

EXAMPLE C: Sulphurization at the Dinoram C / Molybdenum Complex

In a 250 ml reactor equipped with temperature regulation, stirring and a gas bubbling system, a dispersion of 20 g of the complex prepared in Example A is produced in 200 ml of xylene. In the dispersion maintained at 80 ° C., 6.7 g of H₂S are injected; the dark red solid collected after removal of the solvent contains 28.4% molybdenum, 3.8% nitrogen and 23.7% sulfur.

EXAMPLE D: Complex Dinoram O / Molybdenum

The procedure is as in the example, but 9.68 g of sodium molybdate in 35 ml of water are used. 4.8 g of Dinoram O (PM 270) from CECA SA are added at 65 ° C. before heating the medium for 1 hour at 60 ° C.
Dinoram O is an N-alkyl-propylene-diamine. The alkyl radical corresponds to a mixture containing 80% of oleyl radical. We then observe the gradual formation of a white solid which turns blue during acidification. After washing and drying, 8.85 g of a blue solid containing 23% molybdenum are recovered.

EXAMPLE E: Noram C / Molybdenum complex

The procedure is as in Example B, but 7 g of primary monoamine Noram C from CECA SA is used. Noram C is a monoamine, R-NH₂ where R is a mixture of linear and saturated alkyl radicals, 60% C de, 20% C₁₄, 10% C₁₆ and 5% C₁₈. 11 g of a light blue solid containing 26.7% molybdenum are finally recovered.

EXAMPLE F: Stearylamine / Molybdenum Complex

The procedure is as in Example D but 6.74 g of stearylamine from CECA SA are used.
7.68 g of a pale blue solid containing 20.5% of molybdenum and 3.4% of nitrogen are recovered.

EXAMPLE G Primene 81-R / Molybdenum Complex

The procedure is as in Example D but 8g of Primene 81-R ROHM and HAAS are used (PM 185 to 213).
Primene 81-R is a mixture of two monoamines, 1-amino-1,1-dimethyl-decane and 1-amino-1,1-dimethyl-dodecane.
15.75 g of a blue pasty product containing 12.5% molybdenum are collected.

EXAMPLE H: Ethyl-2-hexylamine / Molybdenum complex

The procedure is as in Example B, but 9.9 g of 98% ethyl-2-hexylamine are introduced over 20 minutes in an aqueous solution containing 15.44 g of sodium molybdate and maintained at 60 ° C. After heating for 45 minutes at 60 ° C., acidification is carried out with 23.1 g of 30% sulfuric acid, before washing and drying the product. This is in the form of a white solid containing 36.8% molybdenum and 4.38% nitrogen.

EXAMPLE I p-dodecylaniline / molybdenum complex

The procedure is as in Example A, but an aqueous solution containing 48.4 g of sodium molybdate is acidified with 65.4 g of 30% sulfuric acid. The solution being maintained at 60 ° C., 52.2 g of p-dodecyl aniline are added.
The blue green pasty solid is dissolved in xylene in order to remove water from it by azeotropic distillation.
After removal of the solvent, 80 g of pasty solid containing 11.5% molybdenum and 3.41% nitrogen are recovered.
It can be noted that the complexes prepared in examples A to I are practically insoluble in hydrocarbon compounds as well as in water or in alcohols.

Their incorporation into the overbased additives is therefore not done by dissolution in the hydrocarbon phase, but by incorporation of the complex in the colloidal carbonate particles.

EXAMPLE 1: (comparative)

In a 1 liter reactor equipped with a temperature control of a refrigerant, a stirring system and a gas bubbling device, successively:
- 520 ml of toluene, 131.8 g of alkylxylenesulfonic acid with linear C₁₆-C₁₈ alkyl chain, of molecular weight 430 and with 96% of active material, 168g of diluent oil 100 Neutral solvent, 113.24g of lime slaked at 96% purity and 48 ml of methanol.
After neutralization of the sulfonic acid with lime which can optionally be carried out by heating the reaction medium at 60 ° C. for 30 minutes, 55.2 g of carbon dioxide are then introduced into the mixture maintained at a temperature of 42 ° C.
After carbonation, the methanol and the water produced by the reaction are removed by heating the mixture under partial vacuum. The medium is clarified by filtration using 2% by weight of Diatomées Clarcel DICS from CECA SA. After removing the solvent, 400 g of product containing 13.1% of calcium are recovered.
VA = 321. The product is limpid brown and stable when diluted in mineral or synthetic oils. No clouding or settling is observed after several weeks at 60 ° C.

EXAMPLE 2: comparison

The procedure is as in Example 1, but 219.2 g of alkyl aryl sulfonic acid with branched alkyl chain (didodecylbenzenesulfonic acid) are introduced, the molecular weight of which is 520 and at 70% of active material.
The amount of diluent oil is 108g.
The product is in the form of a brown liquid of VA 304. It is stable when diluted in lubricating oils.

EXAMPLE 3:

The procedure is as in Example 1, but 30 g of the Dinoram C / Molybdenum complex described in Example A are dispersed in 520 ml of xylene, before the introduction of the other reagents. After carbonation and removal of water and methanol, the solid residues are removed by centrifugation. After evaporation of the solvent, 448 g of overbased sulfonate containing molybdenum are recovered; VA = 300, its calcium content is 11.7% and its molybdenum content 2.17%. It is stable when diluted in lubricating oils.

EXAMPLE 4

The procedure is as in Example 1, but 28 g of the complex prepared in Example B are introduced into 520 ml of toluene before the addition of the other reagents.
An overbased sulfonate containing molybdenum is recovered. VA = 303, the calcium content is 11.9% and the molybdenum content 1.94%. It is stable when diluted in oils.

EXAMPLE 5

The procedure is as in Example 2, but 28 g of the complex prepared in Example A are introduced into 520 ml of xylene. After carbonation, elimination of water and methanol, recovery of solid residues by centrifugation then evaporation of the solvent, 440 g of product are collected, VA = 290 and containing 1.69% of molybdenum and 11.5% of calcium. The stability when diluted in oil is remarkable.

EXAMPLE 6

The procedure is as in Example 1, but 28 g of Dinoram C / sulfurized Molybdenum complex as described in Example C is suspended in 520 ml of xylene before the introduction of the other reagents. The rest of the operations are identical to that of Example 1, except that the residues are removed by centrifugation. An overbased sulfonate containing molybdenum is collected, VA = 304. The molybdenum, sulfur and calcium contents are respectively 1.63, 3.4 and 11.7%. The product obtained has a reddish brown color and is stable when diluted in lubricating oils.

EXAMPLE 7

The procedure is as in Example 1, but 28 g of the complex prepared in Example H are suspended in 520 ml of xylene before the introduction of the other reagents. The procedure is the same as in Example 1 except that the residues are removed by centrifugation. A brown product VA = 353 is collected. The calcium and molybdenum contents are respectively 12.2 and 1.97%. The dilution stability in lubricating oils is perfect.

EXAMPLE 8

The procedure is as in Example 1, but 32 g of the complex prepared in Example 1 are introduced before the other reagents in 520 ml of xylene. The procedure is identical to that of Example 1 except that the residues are removed by centrifugation. The overbased sulfonate containing molybdenum is dark brown and stable in oils, VA = 311, its calcium and molybdenum contents are respectively 11.9 and 1.09%.

EXAMPLE 9

The procedure is as in Example 1, but 30 g of the complex prepared in Example A are introduced into the 520 ml of toluene before addition of the other reagents. The following operations are identical to that of Example 1 except that 52.7 g of CO₂ are introduced during carbonation. 448 g of overbased sulfonate containing molybdenum are recovered after centrifugation. VA = 298. The calcium and molybdenum contents are 11.7% and 2.1% respectively. The stability in oils is remarkable.

EXAMPLE 10

The procedure is as in Example 9, but after filtration through diatomaceous earth, 440 g of overbased sulfonate containing molybdenum is recovered, VA = 292. The molybdenum content is 1.96% and the product is clear and stable when diluted in oils.

EXAMPLE 11

The procedure is as in Example 1, but successively is introduced into the reactor - 600 ml of xylene, 132 g of didodecylbenzene sulfonic acid of molecular weight 520g and at 70% of active material - 30g of the complex prepared in Example A - 104g of slaked lime - 52ml of methanol - 4.4ml of ammonia and 90g of diluent oil.
The product collected is brown, clear and stable in oils. The calcium and molybdenum contents are 10 and 2.35 respectively.

EXAMPLE 12 (comparative)

77.8 g of dodecylphenol and 20 g of sulfur chloride are introduced at a temperature of 20 to 30 ° C. into a 250 ml reactor equipped with a temperature-regulating cooler and a gas bubbling device. The mixture is heated under nitrogen sweep and with stirring for one hour at 150 ° C then 1 hour at 180 ° C and finally 1 hour at 200 ° C. The sulfurized dodecylphenol is collected, the respective chlorine and sulfur contents of which are 2200 ppm and 11.4%.

In another 250 ml reactor fitted with a stirring system, a temperature control and a gas bubbling device, 43 g of sulfurized dodecylphenol, 30 g of diluent oil 100 Neutral solvent, 90 ml are successively introduced. xylene, 11.8g of calcium oxide, 66 ml of methanol and 2g of calcium nitrate Ca (NO₃) ₂, 4H₂O. The mixture is brought to reflux for 45 minutes before elimination of the water produced by neutralization. 66 ml of methanol are added to the mixture before carbonating with carbon dioxide the stoichiometric excess of lime, at a temperature of 50 ° C. After carbonation, the residual water and methanol are removed by heating under partial vacuum before recovering the solid residues by filtration.
After evaporation of the solvent, an overbased sulfurized dodecylphenol of brown green color is collected, stable in oils. VA = 240.

EXAMPLE 13

The procedure is as in Example 12, but 5.6 g of the amine / molybdenum complex prepared in Example B is introduced into the reaction medium, just after the elimination of the neutralization water. An overbased phenate, VA is recovered = 243 and whose molybdenum content is 1.89%. The product is stable when diluted in oil.

EXAMPLE 14 (comparative)

The procedure is as in Example 1, but 312g (C₁₄, C₁₈-alkyl) salicylic acid, 37.5g of slaked lime, 150ml of methanol and 100g of diluent oil are introduced into the reactor. After neutralization and carbonation at 42 ° C with 7.65g of CO₂, 30g of lime is added which is carbonated with 10g of CO₂. A stable dark brown additive is collected in the oils. Its calcium content is 7.6%, VA = 205.

EXAMPLE 15

The procedure is as in Example 14, but 27 g of the complex prepared in Example B are introduced before the lime. The product collected at the end of the operations and dark brown, stable in oils. VA = 197, its molybdenum content of 1.77%.

EXAMPLE 16

The performance of new overbased detergents containing molybdenum is examined in laboratory tests of wear, friction and oxidation. The test matrices correspond to lubricants for land engines on the one hand and for marine engines on the other.
First of all, the products are tested in a lubricant formulation used in petrol engines (ELF Presti 15 W 40) by simple substitution of the overbased detergent.

The samples contain 1.25% overbased detergent.

WEAR and FRICTION TEST (lubricant for petrol engines) Falex test : (according to ASTM 2670).

On remarque aussi une forte diminution de l'échauffement liée à la réduction de frottement apportée par les sulfonates surbasés selon l'invention.The test is carried out under the following conditions:
Lapping 5 minutes under 200 lbs (normal load)
3 hours under 540 lbs (normal load)
At the end of the test, the value of the friction torque, the wear in number of teeth of the ratchet wheel and the temperature of the oil bath tested are noted. (The wear is as much lower as the number of teeth, the friction torque and the temperature are lower). Table 1 shows that the overbased sulfonates containing an amine-molybdenum complex allow a reduction of 50 to 70% on average in the friction torque. The use of a conventional molybdenum friction reducer, combined with a reference sulfonate gives a catastrophic result (Example 1 + 1.2% MOLYVAN L) although the molybdenum content in the latter case is of the order of 1200 ppm versus 250 ppm for oils formulated with overbased sulfonates containing molybdenum according to the invention.

There is also a strong decrease in the heating linked to the reduction in friction provided by the overbased sulfonates according to the invention.

4-ball machine (according to ASTM 2783-71)

The test conditions are as follows
speed: 1500 rpm
Duration: 1 hour
Load: 60 Kg
Table 2 gives the results obtained after oxidation of the lubricant for 24 hours at 160 ° C under an oxygen flow rate of 15 l / hour. The rating is obtained by determining the diameter of the imprint. TABLE 2 Example product Cavity diameter in mm 2 (comparison) 1.53 5 0.82 11 0.79

The beneficial effect of the use of molybdenum additives on the anti-wear performance of the lubricant after oxidation is noted.

OXIDATION TEST (TFOUT)

The TFOUT test (thin film oxygen uptake test) is performed on the same essence formulations. It is carried out at 160 ° C. in a pressurized oxygen bomb (90 psi) in the presence of metallic catalyst (Naphtenate of Pb, Cu, Fe, Mn and Sn), of water and of nitro petrol oxidized so as to partially simulate the conditions to which oil can be subjected in a petrol engine.
Table 3 gives values of the induction time, that is to say the time between the start of the test and the start of the rapid pressure drop in the bomb.

The increase in the induction time is significant in the presence of the additive containing the molybdenum-amine complex. TABLE 3 Example product Induction time in minutes 1 comparison 135 4 150 9 153 2 comparison 137 5 159

The overbased detergents containing molybdenum are then tested in a lubricant formulation for marine engines (cylinder oil).

The basicity of the oil is 70 mg KOH / g of which only 20 mg KOH / g provided by the overbased detergent.

The oil also contains 0.5% DTPZ.

WEAR and FRICTION TEST (lubricants for marine engines) Falex test:

Conditions: Lapping 5 minutes under 300 lbs
3 hours
Load 700 lbs (normal load)
These conditions are close to extreme pressure.
Table 4 shows that the cylinder oil for marine engines formulated with the overbased detergents according to the invention makes it possible to significantly reduce or even completely eliminate wear and tear on Falex machines. TABLE 4 Example products DTPZ in% wear in mg 1 (comparison) 0 163 1 (comparison) 0.5 180 4 0 115 4 0.5 73 9 0 1 9 0.5 7 10 0.5 18

Claims (29)

1 - Overbased additives for lubricating oils composed of at least one detergent and an alkali or alkaline earth metal carbonate in a diluent oil, characterized in that they contain at least one organic complex of molybdenum practically insoluble in hydrocarbons. 2 - Additives according to claim 1 characterized in that they contain 0.1 to 10% by weight and preferably 1 to 4% of molybdenum. 3 - Additives according to claims 1 or 2 characterized in that the organic complex of molybdenum is formed with an amine. 4 - Additive according to one of claims 1 to 3 characterized in that the amine-molybdenum complex is prepared by reaction of an inorganic molybdenum compound with an acid reaction with an amine. 5 - Additives according to claim 4 characterized in that the inorganic molybdenum compound is molybdic acid, an alkaline molybdate, sodium hydrogen molybdate, ammonium molybdate, MoOCl₄, MoO₂ Br₂, MO₂O₃Cl₆ or trioxide molybdenum, preferably sodium molybdate or ammonium molybdate. 6 - Additives according to claim 4 characterized in that the amine is a primary, secondary or tertiary aliphatic amine. 7 - Additives according to claim 6 characterized in that the amine is a primary amine, such as oleylamine, stearylamine, dodecylamine, ter-dodecylamine, ethyl-2-hexylamine, cyclohexylamine, 1-amino -1,1-dimethyl-decane and 1-amino-1,1-dimethyl-dodecane. 8 - Additives according to claim 6 characterized in that the amine is a secondary amine whose total number of carbon does not exceed 12. 9 - Additives according to claim 4 characterized in that the amine is an aromatic amine such as para-dodecylaniline. 10 - Additives according to claim 4 characterized in that the amine is a diamine having a primary amine group. 11 - Additives according to claim 10 characterized in that the diamine corresponds to the general formula R₁R₂N- (CH₂) _n -NH₂ (I) where R₁ and R₂ identical or different represent hydrogen or a linear or branched, saturated or aliphatic radical unsaturated in C₁ to C₃₀ and preferably in C₈ to C₂₀, one of the radicals R₁ or R₂ necessarily representing an aliphatic radical and n is between 1 and 8 and preferably between 2 and 4. 12 - Additives according to claim 11 characterized in that in the general formula (I) R₁ is hydrogen and R₂ is a saturated or unsaturated radical derived from fatty acids or mixtures of fatty acids. 13 - Additives according to claim 12 characterized in that R₂ corresponds to at least one saturated or unsaturated alkyl radical in C₁₂ to C₁₈. 14 - Additives according to one of claims 3 to 13 characterized in that the atomic ratio of nitrogen to molybdenum of the complex is between 0.25 and 4 and preferably between 0.5 and 2 and its molybdenum content is between 10 and 45% by weight. 15 - Additives according to one of claims 3 to 14 characterized in that the amine-molybdenum complex is prepared by adding the amine to an aqueous solution of the mineral molybdenum compound, the temperature being maintained between 20 and 100 ° C, preferably between 50 and 90 ° C for 0.5 to 3 hours after the addition of the amine. 16 - Additives according to claim 15 characterized in that the reaction medium is neutralized by addition of a strong mineral acid, preferably sulfuric acid, before or after the introduction of the amine. 17 - Additives according to claims 1 or 2 characterized in that the organic molybdenum complex is formed with an oxygenated compound. 18 - Additives according to claim 17 characterized in that the oxygenated compound is an alkoxylated amine or polyamine. 19 - Additives according to claim 18 characterized in that the amine or polyamine is alkoxylated with ethylene oxide or propylene oxide. 20 - Additives according to claims 18 or 19 characterized in that the alkoxylated amine or polyamine is a derivative of diethanolamine or tri-ethanolamine. 21 - Additives according to claim 17 characterized in that the oxygenated compound is a glycol 1-2, 1-3 or 1-4, preferably ethylene glycol or propylene glycol. 22 - Additives according to claim 17 characterized in that the oxygenated compound is a polyol such as glycerol or trimethylolpropane. 23 - Additives according to one of claims 17 to 22 characterized in that the organic molybdenum complex contains between 7 and 50% by weight of molybdenum. 24 - Additives according to one of claims 1 to 23 characterized in that the organic molybdenum complex is used in the sulfurized form. 25 - Additives according to claim 24 characterized in that the complex is sulfurized by hydrogen sulfide. 26 - Process for the preparation of overbased additives according to claims 1 to 25 by carbonation of a mixture containing a detergent or a detergent precursor, a derivative of an alkali or alkaline earth metal, a nitrogenous and / or oxygenated promoter and optionally a hydrocarbon solvent, a diluent oil and / or water, characterized in that said mixture to be carbonated contains at least one organic complex of molybdenum practically insoluble in hydrocarbons. 27 - Process according to claim 26 characterized in that the detergent is chosen from sulfonates, phenates, naphthenates, salicylates, phosphonates and thiophosphonates alkali or alkaline earth. 28 - Lubricating composition characterized in that it contains a lubricating oil of natural or synthetic origin and 0.5 to 40% by weight, preferably 1 to 30% by weight of an additive according to claims 1 to 25. 29- Composition according to claim 28 characterized in that it contains additives with antiwear, dispersing, antioxidant effect and viscosity improving polymers.