EP0882116B1 - Mixture of earth-alkaline metal alkyl-aryl-sulphonates, its use as additive for lubricating oil and method of preparation - Google Patents

Description

The subject of the present invention is a mixture of alkyl-aryl-sulfonates of alkaline earth metals overbased, its application as detergent-dispersant additives for lubricating oils and methods of preparation of such a mixture.

It is already known to prepare weakly or strongly overbased from sulfonic acids obtained by sulfonation of different alkylaryl hydrocarbons and an excess of alkaline earth base.

• les oléfines ramifiées qui proviennent de l'oligo-polymérisation du propylène en hydrocarbures en C₁₅ à C₄₂, en particulier le tétrapolymère de propylène dimérisé en une oléfine en C₂₄, et
• les oléfines linéaires qui proviennent de l'oligo-polymérisation de l'éthylène en hydrocarbures en C₁₄ à C₄₀.

The alkylaryl hydrocarbons subjected to the sulfonation reaction come from the alkylation by the Friedel and Craft reaction of different aryl hydrocarbons, in particular aromatic, with two different types of olefins:

• branched olefins which come from the oligopolymerization of propylene into C ₁₅ to C ₄₂ hydrocarbons, in particular the propylene tetrapolymer dimerized into a C ₂₄ olefin, and
• linear olefins which originate from the oligo-polymerization of ethylene into C ₁₄ to C ₄₀ hydrocarbons.

However, if it is easy to obtain good dispersion in the medium of the alkaline earth base not fixed in salt form when the acid sulfonic comes from a hydrocarbon obtained by alkylation of a hydrocarbon aryl with a branched olefin, it is not the same when this alkylation is carried out with a linear olefin, in particular containing at least 80 mole% of linear mono-alpha-olefin, as a result of the formation of a skin in the open air.

This poor dispersion is all the more pronounced as the medium contains a greater proportion of sulfonate, i.e. it corresponds, according to standard ASTM D-2.896, to a low basicity index BN (at know between 3 and 60), therefore with a low content of free lime and the absence of carbon dioxide and carbonate.

Indeed, during the alkylation reaction with benzene or a other aromatic or aryl hydrocarbon, the molar proportion of the group cyclic hydrocarbon corresponding in position 1 or 2 of the olefinic chain starting line is around 25%.

However, this high proportion of alkylaryl hydrocarbon having position 1 or 2 of the linear alkyl chain an aryl radical results in a sulfonate which, when prepared according to the process described, for example, in French patent 2,564,830 of the company OROGIL, former name of the applicant, has hygroscopic properties such that a superficial "skin" is formed, making this product unacceptable as an additive for lubricating oil.

In addition, the formation of this superficial skin is generally accompanied by a very slow filtration speed, a high viscosity, low calcium intake, performance deterioration rust and the undesirable appearance of a cloudy appearance, or even sedimentation, when the sulfonate thus prepared is added at a rate of 10% by weight to a standard lubricating oil and stored for review.

The applicant has carried out chromatographic studies to identify each of the different isomers differing by the position of the radical aryl on the carbon atom of the linear alkyl chain and examined their respective influence on the properties of the corresponding alkyl-aryl sulfonates of alkaline earth metal obtained from these different isomers.

She thus discovered that she could overcome the disadvantages above, insofar as the molar proportion of aryl hydrocarbon, other than benzene, attached to carbon atoms located in position 1 or 2 of the linear alkyl chain was between 0 and 13%, preferably between 5 and 11% and more particularly between 7 and 10%.

And this discovery was the subject of a French patent application filed on March 8, 1995 under No. 95 02709 by the plaintiff.

However, it had failed to achieve results satisfactory, when the aryl hydrocarbon was benzene because it had no never, until now, been able to avoid skin formation with the use of this aromatic hydrocarbon, even if it was alkylated with a mono-olefin linear of great length of chain on the carbon atom located in position 1 or 2 of said chain in a molar proportion of between 0 and 13% and preferably between 5 and 11% and more particularly between 7 and 10%.

(a) au moins 50 % et au plus 85 % en poids d'un mono-alkylphényl-sulfonate dans lequel le substituant monoalkyl est une chaíne linéaire, contenant entre 14 et 40 atomes de carbone et le radical phényl-sulfonate de métal alcalino-terreux est fixé, dans une proportion molaire comprise entre 0 et 13 %, de préférence entre 5 et 11 % et plus particulièrement entre 7 et 10 %, en position 1 ou 2 de la chaíne alkyle linéaire et

(b) au moins 15 % et au plus 50 % en poids d'un alkyl-aryl-sulfonate lourd choisi parmi :

(i) les dialkyl-aryl-sulfonates dans lesquels le radical aryle peut être un radical phényle substitué ou non, tel qu'en particulier les radicaux phényle, tolyle, xylyle, éthyl-phényle ou cuményle, et dans lesquels les deux substituants alkyle sont tous deux des chaínes alkyles linéaires, dont la somme des atomes de carbone est comprise entre 16 et 40, de préférence entre 18 et 40 atomes de carbone ou

(ii) les mono- ou poly-alkyl-aryl-sulfonates dans lesquels le radical aryle peut être un radical phényle substitué ou non, tel qu'en particulier les radicaux phényle, tolyle, xylyle, éthyl-phényle ou cuményle, et dans lesquels le ou les substituants alkyl sont des chaínes ramifiées, dans lesquelles la somme des atomes de carbone est en moyenne comprise entre au moins 15 et jusqu'à 48 atomes de carbone,

   ledit mélange d'alkyl-aryl-sulfonates ayant une teneur molaire maximale de 10 %, et de préférence inférieure ou égale à 8 % en monoalkylphényl sulfonate linéaire, dans lequel le radical phényl-sulfonate est substitué en position 1 ou 2 de la chaíne alkyle linéaire.Following further studies, the Applicant has now discovered that the above-mentioned drawbacks were overcome provided that a mixture of alkaline earth metal alkaline earth metal sulfonates comprising:

(A) at least 50% and at most 85% by weight of a mono-alkylphenyl-sulfonate in which the monoalkyl substituent is a linear chain, containing between 14 and 40 carbon atoms and the alkali metal phenyl-sulfonate radical earthy is fixed, in a molar proportion between 0 and 13%, preferably between 5 and 11% and more particularly between 7 and 10%, in position 1 or 2 of the linear alkyl chain and

(b) at least 15% and at most 50% by weight of a heavy alkyl-aryl sulfonate chosen from:

(i) dialkyl-aryl-sulfonates in which the aryl radical may be a substituted or unsubstituted phenyl radical, such as in particular the phenyl, tolyl, xylyl, ethyl-phenyl or cumenyl radicals, and in which the two alkyl substituents are both linear alkyl chains, the sum of the carbon atoms of which is between 16 and 40, preferably between 18 and 40 carbon atoms or

(ii) mono- or poly-alkyl-aryl-sulfonates in which the aryl radical may be a substituted or unsubstituted phenyl radical, such as in particular the phenyl, tolyl, xylyl, ethyl-phenyl or cumenyl radicals, and in which the alkyl substituent (s) are branched chains, in which the sum of the carbon atoms is on average between at least 15 and up to 48 carbon atoms,

said mixture of alkyl-aryl-sulfonates having a maximum molar content of 10%, and preferably less than or equal to 8%, in linear monoalkylphenyl sulfonate, in which the phenyl-sulfonate radical is substituted in position 1 or 2 of the alkyl chain linear.

The mixtures according to the invention preferably contain between 75 and 85% by weight of mono-alkyl-phenyl-sulfonate, as defined in (a) above and between 15 and 25% by weight of heavy alkyl-aryl sulfonate as defined in (b), (i) or (ii) above with the same maximum content for mixing monoalkyl sulfonate substituted in position 1 or 2.

Indeed, said mixtures have a set of properties solubility in lubricating oil, filtration speed, viscosity, dispersion of impurities (carbonaceous particles), incorporation of metal alkaline earth in the medium, anti-rust properties, an absence of disorder and an absence or delay in the formation of superficial skin, which makes them particularly attractive as detergent-dispersant additives in this type of oil.

This result is all the more surprising since the use of a monoalkyl (linear) -phenyl-sulfonate, as defined in (a) above, it is say obtained by alkylation of benzene with a linear olefin containing at minus 80% by mole of linear mono-alpha-olefin, having an index of low BN basicity (i.e. between 3 and 60), had so far never allowed to obtain all the properties necessary for their use as detergent-dispersant additives for lubricating oils.

The first of the two ingredients used in the composition of mixtures forming the subject of the present invention, in a proportion predominant compared to the second, is a mono-alkyl-phenyl-sulfonate, in which the linear mono-alkyl substituent, originating from a linear olefin, as defined above, must be substituted by the phenyl-sulfonate radical in a certain proportion in position 1 or 2 of the linear alkyl chain.

The content of 13% is the threshold from which it is no longer possible obtain an ingredient making it possible to obtain a mixture having both a suitable improvement of the various properties listed above.

The 11% content constitutes the upper limit of the ingredient prepared on an industrial scale and for which it is sought to obtain a mixture having all of the above properties.

And that of 10% is the value sought during manufacturing process of the additive used in the composition of the mixture subject to the present invention.

Without wanting to be bound by any scientific explanation, it is assumed that the more the phenyl radical is attached to a carbon atom located in a position distant from the ends of the hydrocarbon chain of the linear olefin, plus the hydrophobic character of the alkylphenyl hydrocarbon corresponding is marked, hence the good properties of mixtures of alkyl phenyl sulfonates according to the invention.

However, the hydrophobic nature of this alkylphenyl hydrocarbon is not sufficient to confer corresponding sulfonate properties making it suitable as a detergent-dispersant additive for oil lubricant.

To achieve this, it is indeed necessary to add, according to the invention, another heavy alkyl aryl sulfonate in a minimum proportion of 15% and maximum of 50% and preferably between 15% and 25% in weight, based on the mixture of sulfonates.

As previously indicated, this heavy alkyl aryl sulfonate can be of two types.

It may first of all be a dialkyl-aryl-sulfonate, in which the aryl radical is a substituted or unsubstituted phenyl radical, such as in particular phenyl, tolyl, xylyl, ethyl-phenyl or cumenyl and in which each of the two alkyl groups comes from a linear olefin which may contain at least 80 mol% of linear mono-alpha-olefin and the sum of the atoms of carbon in these two linear alkyl groups is between 16 and 40 and preferably between 18 and 40 carbon atoms.

These heavy dialkyl aryl sulfonates can be obtained from many ways.

A first process, in several stages, consists in carrying out first the synthesis of the corresponding monoalkylaryl hydrocarbon in which the linear monoalkyl radical has the chain length of atoms of shortest carbons then alkylation of this hydrocarbon with an olefin linear containing at least a number of carbon atoms sufficient to meet the ranges specified above.

A second process consists in a direct alkylation of an aromatic carbide by a mixture of linear alpha-olefins from C ₈ to C ₄₀ in an aromatic carbide / olefin molar ratio close to 0.5 so as to obtain a dialkyl-aryl hydrocarbon in which the sum of the carbon atoms of the two linear alkyl chains meets the definition given above.

The heavy dialkyl-phenyl-sulfonates can also be products marketed under the name of "LAB Bottoms": they are heavy by-products obtained during the manufacture of linear alkyl-benzenes products (Linear Alkyl Benzene) in C ₁₂ , used commonly, after sulfonation and neutralization with soda, in household detergents. During its manufacture, the linear C ₁₂ alkylbenzene is separated by distillation and the heavy fraction, called “LAB Bottoms”, consists mainly of dialkylbenzenes substituted in para and meta positions and, in a smaller proportion, certain heavy monoalkyl-benzene, originating from the oligopolymerization of the starting linear olefin.

The other type of heavy alkyl aryl sulfonate used in mixtures according to the invention is a mono- or poly-alkyl-aryl-sulfonate, in which the one or more alkyl substituents are no longer, as in the previous ingredients a linear chain, that is to say from the oligo-polymerization of ethylene, but branched chains, that is to say from oligo-polymerization propylene, and in which the sum of the atoms of carbon is on average at least 15 and up to 48 carbon atoms.

These branched heavy mono- or poly-alkyl-aryl sulfonates can be obtained by alkylation of an aromatic hydrocarbon with a heavy propylene hydrocarbon, on average C ₁₅ to C ₂₁ , generally obtained as a by-product during the manufacture of the propylene tetramer.

• soit dans un seul réacteur d'alkylation, où on utilise un large excès molaire de carbure aromatique par rapport à l'oléfine, pouvant atteindre couramment 10 : 1 et, après distillation du carbure aromatique et de l'oléfine n'ayant pas réagis et des alkylats dont la partie alkyle comporte moins de 13 atomes de carbone ou moins, on récupère un produit mono- ou poly-alkylarylique lourd, qui peut être directement sulfoné et converti en sulfonate ;
• soit dans deux réacteurs en série, où on utilise, dans le premier, un faible excès molaire du carbure aromatique par rapport à l'oléfine, au maximum de 1,5 et, dans le second, un plus large excès d'au moins 2 et de préférence 5, dans le but d'augmenter la masse moléculaire des alkylats et qui se traduit par un mélange complexe de monoalkyl-aromatique lourds et de polyalkyls-aromatiques, du fait de la fragmentation et de l'oligopolymérisation de l'oléfine ramifiée utilisée dans la réaction d'alkylation.

Such an alkylation reaction can be carried out in two ways:

• either in a single alkylation reactor, where a large molar excess of aromatic carbide relative to the olefin is used, which can commonly reach 10: 1 and, after distillation of the unreacted aromatic carbide and olefin and alkylates in which the alkyl part contains less than 13 carbon atoms or less, a heavy mono- or poly-alkylarylate product is recovered, which can be directly sulfonated and converted to sulfonate;
• either in two reactors in series, where, in the first, a small molar excess of the aromatic carbide relative to the olefin is used, at most 1.5 and, in the second, a larger excess of at least 2 and preferably 5, in order to increase the molecular weight of the alkylates and which results in a complex mixture of heavy monoalkyl-aromatics and polyalkyls-aromatics, due to the fragmentation and the oligopolymerization of the branched olefin used in the alkylation reaction.

Branched mono- or poly-alkyl-benzenes can also be heavy by-products obtained during the manufacture of dodecyl benzene, marketed under the name of BAB, which is the abbreviation corresponding to "Branched Alkyl Benzene". When manufacturing this last, a large molar excess of benzene is alkylated with tetramer of propylene and the heavy by-product is that which remains at the bottom of the column during the top distillation of dodecyl-benzene. This heavy by-product consists essentially of a heavy monoalkyl-benzene where the number of atoms of carbon in the branched alkyl chain is greater than or equal to 13 and dialkylbenzenes para and meta. As an indication, the molecular mass of dodecylbenzene is 242, while that of the heavy by-product obtained during of its manufacture, can range from 300 to 390.

The various alkylation reactions mentioned above are carried out in a conventional manner with Friedel and Craft catalysts, such as for example HF or Al Cl ₃ .

The Applicant has discovered that mixtures of alkyl aryl sulfonates according to the present invention were not subject to the formation of a superficial skin, when stored at room temperature, if their molar content into monoalkyl-phenyl-sulfonate in which the substituent phenyl-sulfonate substituted in position 1 or 2 on the linear alkyl radical is less than 10% and preferably 8% or less.

The 10% limit is the threshold beyond which skin formation appears within 48 hours of storage, making the mixture difficult to use as an additive for lubricant.

On the other hand, that of a maximum of 8% corresponds to mixtures for which the formation of a superficial skin appears only after a storage time of several days, or even one or more weeks, this which makes them suitable as detergent-dispersants for lubricating oils.

Without wishing to be bound by any scientific explanation, the Applicant assumes that the presence of a phenyl-sulfonate substituent in position 1 or 2 of a linear alkyl group very particularly absorbs water and this absorption of water would lead to the harmful formation of a skin superficial when storing the mixture containing it in the open air.

A subject of the invention is also methods of preparation of such a mixture of alkyl aryl sulfonates.

A first method according to the invention comprises the mixture of corresponding alkyl aryl hydrocarbons, the sulfonation of this mixture and the reaction of the resulting sulfonic acids with an excess of alkaline earth base.

A second method according to the invention comprises the preparation separated from each of the two alkyl aryl sulfonic acids, their mixture and their reaction with an excess of alkaline earth base.

A third method according to the invention consists in preparing separately each of the alkyl aryl sulfonates used in the composition of mixtures and their mixing in the required proportions.

The first process is preferred because the sulfonates obtained have better solubility in lubricating oil than sulfonates obtained in the other two processes.

To prepare the first incoming alkylphenyl sulfonate, by predominant proportion, in the mixtures according to the invention, the procedure is first to the alkylation of benzene with a linear olefin according to the reaction of Friedel and Craft.

This alkylation reaction can be carried out either directly with a linear mono-olefin, already isomerized, containing a molar proportion between 0 and 13%, preferably between 5 and 11% and more particularly between 7 and 10% alpha-olefin.

It can also be carried out, if one starts from an alpha-olefin linear, not isomerized at the start, i.e. containing a proportion conventional molar of about 80% alpha-olefin, splitting the two-stage alkylation reaction, namely a first stage, in which the molar ratio between benzene and linear mono-olefin is at maximum of 1.5 and preferably 1, and a second step, in which said ratio is at least 2 and preferably 5.

In both the alkylation process, depending on the reaction from Friedel and Craft, an alkylphenyl hydrocarbon with the desired molar proportion of phenyl isomers in position 1 or 2 of the linear alkyl chain.

The catalyst used for the Friedel and Craft reaction is chosen preferably from hydrofluoric acid, aluminum chloride, fluoride boron, a sulfonic ion exchange resin or an activated clay acid.

The conditions of this alkylation reaction depend on the nature of the Friedel and Craft catalyst used.

In the case of hydrofluoric acid, the temperature is preferably between 20 and 70 ° C and the pressure between atmospheric pressure and 10.10 ⁵ Pa.

In the case of aluminum chloride, or boron fluoride, these conditions are those described in the literature concerning this reaction.

Finally, in the case of a solid Friedel and Craft catalyst, such as a sulfonic ion exchange resin or an acid-activated clay, the temperature of the alkylation reaction is between 40 and 250 ° C. and the pressure between atmospheric pressure and 15.10 ⁵ Pa.

Although the plaintiff did not wish to be bound by a any explanation, it would seem that maintaining, at the start of the reaction of alkylation, of a molar ratio of benzene to linear mono-alpha-olefin maximum of 1.5 and preferably 1, in the presence of a Friedel and Craft, causes a migration of the double bond of the linear olefin from the terminal position in alpha to a more central position of the olefin, where the phenyl radical is attached.

It is assumed that the alpha-olefin reacts with the catalyst of Friedel and Craft to form an intermediate carbonium ion, which isomerizes, the more easily as the relative proportion of alpha-olefin is more important.

The alkylation of this carbonium ion takes place according to a reaction of aromatic electrophilic substitution where a hydrogen atom of benzene is substituted by a carbon atom of the linear olefinic chain.

This isomerization reaction is unexpected because, so far, the alkylation reaction, strongly exothermic, was always carried out with a strong molar excess of benzene relative to the starting linear olefin.

It should be noted, however, that this first step isomerization must be followed by a second step during which the molar proportion of benzene is 2 and preferably 5 times greater than that of the starting linear olefin, this in order to decrease the proportion of non-olefin reacts and accordingly increase the conversion rate of the olefin starting linear in alkylate up to a rate close to 100%.

In the context of the present description, the term radical or linear alkyl or linear olefin substituent denotes a radical or an olefin or a mixture of radicals or straight chain olefins obtainable by oligo-polymerization of ethylene, and which contain between 14 and 40, preferably between 16 and 30 and more particularly between 20 and 24 atoms of carbon and where the molar proportion of mono-alpha-olefin is at least 80%.

Specific examples of linear olefins meeting this definition are constituted by C ₁₆ , C ₁₈ olefins, by C ₁₄ to C ₁₆ olefin sections, C ₁₄ to C ₁₈ , C ₁₆ to C ₁₈ or C ₂₀ to C ₂₄ or by combinations of several of them.

The linear C ₁₄ to C ₄₀ mono-alpha-olefins, which can be obtained by direct oligo-polymerization of ethylene, have an infrared absorption spectrum exhibiting an absorption peak at 908 cm ^-1 , characteristic the presence of an ethylenic double bond at the end of the chain, on the carbon atoms occupying positions 1 and 2 of the olefin; there are also two other absorption peaks at wavelengths of 991 and 1,641 cm ^-1 .

On the other hand, the linear C ₁₄ to C ₄₀ mono-olefins isomerized, that is to say in which the molar proportion of alpha-olefin is between 0 and 13%, preferably between 5 and 11%, and more particularly between 7 and 10%, have an infrared absorption spectrum showing no significant peak in the regions of 908, 991 and 1.641 cm ^-1 , but which, on the other hand, shows the appearance of a peak d absorption at 966 cm ^-1 , characteristic of a trans internal ethylenic double bond.

These isomerized mono-olefins can be obtained by heating, under atmospheric pressure at a temperature of the order of 120 ° C. for a period of 144 hours, from a cut of C ₂₀ to C ₂₄ alpha mono-olefins, obtained by polymerization of ethylene, on a catalyst based on pentacarbonyl iron, for example, as described in patent US-A-5,320,762.

Figures 1 and 2 attached illustrate this difference, showing the infrared spectra of a section of C ₂₀ to C ₂₄ linear mono-alpha-olefins, obtained directly by polymerization of ethylene, in Figure 1 (reference: without, solvent: without, concentration: 100%, thickness 0.05, number of scans: 16), and after isomerization of this, cut, by passage over a pentacarbonyl iron catalyst, to reduce its molar alpha content -olefin less than 10%, in Figure 2 (reference: without, solvent: without, concentration: 100%, thickness 0.05, number of scans: 16).

The aromatic hydrocarbon with which these linear olefins are reacted is exclusively benzene, to the exclusion of any other benzene hydrocarbon, in particular to the exclusion of any alkyl derivative of benzene in which the aromatic nucleus is substituted by one or two C ₁ to C ₅ alkyl radicals.

The alkylation reaction according to the Friedel and Craft reaction for obtain the alkylphenyl hydrocarbon corresponding to the first sulfonate of the mixing according to the present invention can be carried out in two stages, as indicated previously, by continuous implementation in two successive reactors in the presence of the catalyst.

In the first reactor, the molar proportion of benzene per ratio to the linear olefin is at most 1.5 and preferably 1.2 and more particularly of 1, to slow down the alkylation reaction and promote a isomerization of the starting linear mono-alpha-olefin by migration of its double bond towards the middle of the olefin hydrocarbon chain.

In the second reactor, the molar proportion of benzene with respect to the linear mono-alpha-olefin at least 2: 1 and, from preferably 5: 1 and above to complete the alkylation reaction.

And, at the end of the successive passage in the two reactors, we collects the Friedel and Craft catalyst by phase separation, and collects excess benzene by distillation, as in processes earlier.

The same alkylphenyl hydrocarbon can also be obtained by separately carrying out the isomerization of the alpha-olefin from start then adding benzene to carry out the reaction alkylation catalytic, with a Friedel and Craft catalyst.

The alkylation reaction according to the Friedel and Craft reaction for obtaining the heavy alkyl-aryl hydrocarbon corresponding to the second sulfonate of the mixture according to the present invention is either a dialkyl-aryl obtained by recovery at the bottom of the column of the reaction products of a aromatic hydrocarbon with a linear mono-alpha-olefin in which the sum of the carbon atoms of the two monoalkyl substituents is between 16 and 40 and preferably between 18 and 40 carbon atoms, either a mono- or poly-alkyl-aryl recovered at the bottom of the column, during the distillation of the products of the alkylation reaction of an aromatic hydrocarbon with a branched olefin in which the sum of the carbon atoms present in the various branched alkyl substituents have an average of at least minus 15 carbon atoms.

The next step of sulfonation of each of the hydrocarbons alkyl-aromatics or a mixture of different alkyl-aromatic hydrocarbons corresponding to the mixture according to the invention is carried out according to techniques known per se, for example by reaction of the product of step alkylation, with concentrated sulfuric acid, with an oleum, with sulfuric anhydride diluted in nitrogen or air or with anhydride sulfuric dissolved in sulfur dioxide. This reaction of sulfonation can also be carried out by bringing the ingredients into contact (alkylate and sulfuric anhydride) in the form of a film falling in currents of same sense or opposite directions. After the sulfonation, the acid or the different sulfonic acids obtained can be purified by techniques conventional, such as washing with water or by heat treatment under stirring with nitrogen bubbling (see for example the technique described in the French patent No. 93 11709 of the applicant).

The next stage of reaction of the acid or sulphonic acids with an excess of alkaline earth base can be carried out by adding a alkaline earth metal oxide or hydroxide, such as magnesium, calcium or barium and especially lime.

This neutralization step is implemented within a dilution oil, with an alcohol with a boiling point above 80 ° C and preferably with a carboxylic acid comprising from 1 to 4 atoms of carbon, in the presence of water, as described in particular in the application for French patent 2,564,830 cited above.

Among the alcohols with a boiling point higher than 80 ° C., linear or branched aliphatic mono-alcohols containing from 4 to 10 carbon atoms are preferably chosen, such as isobutanol, 2-ethylhexanol and oxo alcohols in C ₈ to C ₁₀ .

Among the carboxylic acids which can be used, may preferably include formic acid, acetic acid and mixtures thereof.

Among the dilution oils likely to be suitable in the step neutralization, there may be mentioned paraffinic oils such as oil 100 Neutral, as well as naphthenic or mixed oils.

After removal of the water and alcohol, it is filtered to remove the solids and the alkaline earth metal alkyl aryl sulfonates are collected obtained.

If the alkyl aryl hydrocarbons have not already been mixed corresponding or the corresponding sulfonic acids, we can mix with this stage the alkyl aryl sulfonates to obtain the mixtures according to the invention in the desired proportions.

The mixtures of alkyl-aryl sulfonates according to the invention are of preferably slightly overbased, that is to say that their basicity index BN, measured according to ASTM-D-2896, can range from 3 to 60 and they can be used in particular as dispersing detergents for lubricating oils.

The mixtures of alkyl-aryl sulfonates according to the invention are particularly interesting, when their basicity index is low and corresponds to a range of BN between 10 and 40.

It should be noted that this is the first time that it is possible to use alkylphenyl sulfonates having such a basicity index, namely between 3 and 60 and preferably between 10 and 40 and coming exclusively from alkylation of benzene, as detergent-dispersant additives for oil lubricant with satisfactory properties, and without the need add calcium or ammonium chloride to decrease the viscosity.

In particular, the mixtures of alkyl-aryl-sulfonates according to the present invention, in which the proportion of monoalkyl (linear) -phenyl-sulfonate (component a) defined above) is between 50 and 75% by weight, do not require the addition of chloride ions, in the form in particular calcium or ammonium chloride, to satisfy the whole properties, listed above, to serve as detergent-dispersant additives for lubricating oils.

This is not the case for the same mixtures containing 75 to 85% in weight of said monoalkyl (linear) phenyl sulfonate, for which it is preferable to add chloride ions.

Indeed, so far, only alkyl-aryl-sulfonates from alkylation of aryl hydrocarbons other than benzene or alkyl-aryl sulfonates from alkylation with branched olefins were considered necessary to present all of the properties making them suitable as detergent-dispersant additives for lubricating oil.

The mixtures of alkyl-aryl sulfonates according to the invention can be added to lubricating oils in proportions ranging from 1 to 15% by weight depending on the nature of the lubricating oil.

For example, for a gasoline engine oil, we can add up to 1.7% by weight, for a diesel engine or engine oil marine, up to 3.5% by weight and finally for a protective car oil new, up to 11.5% by weight.

Lubricating oils to which mixtures can be added according to the present invention can be lubricating oils based naphthenic, paraffinic or mixed; they can consist of oils mineral or come from coal distillation products or be made up by synthetic oils, such as polymers of alkenes or esters mineral acids or carboxylic acids.

The present invention will now be described using the following examples which are only intended to illustrate implementations particular aspects of the various aspects of the invention.

In these examples there are a number of results of tests, obtained by the following measurement methods

Viscosity at 100 ° C in cSt

The viscosity is measured, at the temperature of 100 ° C., after dilution of the sample of product to be measured in 100N oil, up to obtaining a solution having a total calcium level of 2.35% in weight. When the product to be measured has a lower total calcium level at 2.35% by weight, the viscosity is then measured as it is according to the method ASTM D-445.

Compatibility

The purpose of this method is to assess the appearance and stability storage of additives and corresponding oils containing them.

This method is applicable to additives for lubricants.

An additive based on monosuccinimide, zinc dithiophosphate and comprising approximately 75% by weight of the mixture of sulfonates to be tested, additive which is put in a 350 Neutral base oil. The appearance of the solution is examined after 30 days at temperature ambient.

The appearance of the products is evaluated before and after storage and the results are qualified as "GOOD" or "BAD" depending on whether there is maintenance or not of a single phase without deposition by sedimentation.

DISPERSION (TASK TEST)

The purpose of this method is to assess the dispersive properties an oil or an additive and predict its level of performance (deposits, mud) compared to a reference oil.

It is generally applicable to land motor oils and sailors.

Tache N°1 : température ambiante sans eau

Tache N°2 : 10 mn à 200°C sans eau

Tache N°3 : 10 mn à 250°C avec eau

Tache N°4 : température ambiante avec eau

Tache N°5 : 1 mn à 200°C avec eau

Tache N°6 : 10 mn à 200°C avec eau.

According to this method, the dispersive power of the oil is obtained by performing a paper chromatography of a mixture of oil to be tested and artificial mud under the following conditions:

Task N ° 1: room temperature without water

Task N ° 2: 10 min at 200 ° C without water

Task N ° 3: 10 min at 250 ° C with water

Task N ° 4: room temperature with water

Task N ° 5: 1 min at 200 ° C with water

Task N ° 6: 10 min at 200 ° C with water.

The spots are observed after 48 hours of rest, manually or using the CCD photometer.

On each spot, we measure the diameter (d) of diffusion of the mixture and the diameter (D) of diffusion of the oil alone and the ratio d / D x 100 is calculated.

The dispersive power of the oil is obtained by comparing the sum 6 stains to the value found on one of the reference oils which must be tested in the same measurement series.

The addition of the d / D x 100 ratios under the six conditions listed above corresponds to a maximum dispersive power of 600, corresponding to an ideal dispersion of 100% in all conditions. In the results of this test, the higher the number, the better the power dispersive oil.

EXAMPLES 1 to 10 a) Synthesis of the alkylate

The alkylate is synthesized in a pilot hydrofluoric acid alkylation plant, which consists of two reactors in series of 1.126 liters each and a decanter of 15 liters where the organic phase is separated from the phase containing hydrofluoric acid, all of this equipment being maintained under a pressure of approximately 4 × 10 ⁵ Pa.

The organic phase is then drawn off via a valve and expanded to atmospheric pressure and then the benzene is removed by topping, ie heating to 160 ° C at atmospheric pressure.

The mineral phase, after racking, is neutralized by potash.

(i) mise en oeuvre dans un ou deux réacteurs :

• dans le cas d'utilisation d'un seul réacteur, le rapport molaire benzène/oléfine est de 10, ce qui est très élevé, et le deuxième réacteur est court-circuité ;
• dans le cas de l'utilisation de deux réacteurs, le rapport molaire benzène/oléfine est relativement faible dans le premier réacteur, de l'ordre de 1 à 1,5 et il est plus important dans le deuxième réacteur, de l'ordre de 2 à 10 ; en outre, le rapport de l'acide fluorhydrique à l'oléfine en volume est de 1 dans le premier réacteur et de 2 dans le deuxième.

The variables of the alkylation reaction are as follows:

(i) implementation in one or two reactors:

• if a single reactor is used, the benzene / olefin molar ratio is 10, which is very high, and the second reactor is short-circuited;
• in the case of the use of two reactors, the benzene / olefin molar ratio is relatively low in the first reactor, of the order of 1 to 1.5 and it is higher in the second reactor, of the order of 2 to 10; in addition, the ratio of hydrofluoric acid to olefin by volume is 1 in the first reactor and 2 in the second.

b. Distillation of the alkylate

In the case of alkylation of benzene by a linear C ₂₀ to C ₂₄ olefin, a light fraction does not form, that is to say of alkyl benzene in which the alkyl radical is less than C ₁₃ ; it therefore suffices to topping the unreacted benzene to obtain the corresponding alkylate.

• température en tête de colonne :   262°C
• température de fond de colonne :   302°C
• pression :   187.10² Pa (187 millibars)

In all other cases, a slight fraction occurs during the catalytic alkylation reaction, which must be eliminated, in the same way as excess benzene, on a column to be distilled under vacuum; by light fraction means any alkyl benzene having an alkyl chain lower than C ₁₃ ; to achieve such a light fraction, the final distillation conditions are as follows:

• temperature at the top of the column: 262 ° C
• column bottom temperature: 302 ° C
• pressure: 187.10 ² Pa (187 millibars)

vs. Sulfonation of the alkylate

The sulfonation is carried out directly on the mixture of the 2 alkylates of the present invention, wherein the molar proportion of the radical phenyl substituted on the carbon atoms in position 1 or 2 of the alkyl radical is determined in relation to the whole mixture of alkylates subjected to the sulfonation reaction.

This reaction is carried out using sulfuric anhydride SO ₃ , produced by passing a mixture of oxygen and sulfurous anhydride SO ₂ through a catalytic oven containing vanadium oxide V ₂ O ₅ .

The gas thus produced is introduced at the head of a sulfonation 2 meters long and 1 cm in diameter in a co-current alkylate stream.

• débit de SO₃ fixé à 76 g/h,
• débit de l'alkylat compris entre 350 et 450 g/h, selon le rapport molaire SO₃/alkylat désiré qui varie de 0,8 à 1,2,
• température de sulfonation comprise entre 50 et 60°C,
• et avec de l'azote comme gaz vecteur pour diluer le SO₃ à 4% en volume.

The resulting sulfonic acid is recovered at the bottom of the reactor. The sulfonation conditions are as follows:

• SO ₃ flow rate fixed at 76 g / h,
• flow rate of the alkylate of between 350 and 450 g / h, depending on the molar ratio SO ₃ / desired alkylate which varies from 0.8 to 1.2,
• sulfonation temperature between 50 and 60 ° C,
• and with nitrogen as the carrier gas to dilute the SO ₃ to 4% by volume.

After the sulfonation reaction, the residual sulfuric acid is removed by heat treatment after dilution with 10% 100 N oil, bubbling with nitrogen at the rate of 10 l / h / kg of product and stirring at 85 ° C., until to obtain a lower residual content of H ₂ SO ₄ (0.5% by weight maximum).

The analyzes appearing in the table below relating to exemplary embodiments of the present invention correspond to the product obtained after heat treatment.

d) Over-alkalization

In this step, relative molar proportions of Ca (OH) ₂ and of sulfonic acid obtained in the previous step are reacted, so as to obtain a proportion of 37% of lime not neutralized by sulfonic acid in the product. final. It is this proportion of 37% of non-neutralized lime which will make it possible to obtain in the final sulfonate a BN of the order of 20 according to standard ASTM D-2.896.

To achieve this, an amount of Ca (OH) _{2 is added} which does not correspond to the stoichiometric neutralization of the amount of sulfonic acid reacted, namely 0.5 mole of Ca (OH) ₂ per mole of this acid. sulfonic, but an excess of Ca (OH) _{2 is added} relative to this stoichiometric quantity, that is to say a proportion of 0.73 mole of Ca (OH) ₂ per mole of sulfonic acid, to obtain a BN d 'around 20.

The conditions for the overbasing reaction used are those described in the aforementioned French patent application 2,564,830 of the OROGIL company, former name of the plaintiff, and published on November 29 1985.

The performances obtained with mixtures of alkyl-aryl-sulfonates according to the invention are summarized in the table at the end of this specification.

EXAMPLE 1

In this example, 80% by weight of a linear alkylate obtained by alkylation of benzene with a normal C ₂₀ to C ₂₄ alpha-olefin is mixed, which will hereinafter be called the reference linear product, with 20% by weight. weight of a heavy branched alkylate, also called "BAB Bottom", obtained by alkylation of benzene with propylene tetramer and elimination of light aromatic fractions (with an alkyl chain lower than C ₁₃ ).

The sulfonation is carried out on the mixture of alkylates above.

EXAMPLE 2

80% by weight of reference linear alkylate are mixed with 20% of a heavy alkylate of linear dialkyl-phenyl type obtained in the manner next :

In a first alkylation reactor, benzene and a composition of linear C ₈ alpha-olefins are reacted, in a molar ratio of benzene to olefin of 1 and an HF / olefin volume ratio of 1, to a temperature of 45 ° C. and a pressure of 4.10 ⁵ Pa. A phenyl hydrocarbon substituted by a single C ₈ alkyl radical is obtained at the outlet of this first reactor, which will serve as an aryl hydrocarbon to be alkylated in the following reactor .

Said C ₈ substituted monoalkyl phenyl hydrocarbon is transferred to a second alkylation reactor where the same amount of HF as in the first reactor is introduced and linear C ₁₈ alpha-olefin in the molar proportion of 3 moles of said hydrocarbon substituted phenyl per 1 mole of linear C ₁₈ alpha-olefin.

After topping the unreacted benzene, all the alkylphenyl products are distilled in which the sum of the atoms present in the alkyl chain or chains amounts to 18 carbon atoms included. A product is collected at the bottom of the column which is mainly a linear dialkyl phenyl in which one of the alkyl substituents is C ₈ and the other C ₁₈ .

The sulfonation is carried out on the above mixture of alkylates defined.

EXAMPLE 3

80% by weight of linear reference alkylate and 20% are mixed. by weight of a branched heavy alkylate obtained in the following way:

In a first reactor, the catalytic alkylation of the benzene by propylene tetramer with a molar ratio benzene / propylene tetramer of 1.2 and an HF / tetramer ratio of propylene 1 by volume.

• aromatique/tétramère du propylène   5,8 en mole
• HF/tétramère du propylène   1 en volume

The product thus obtained is transferred to a second reactor where hydrofluoric acid and benzene are added in the following proportions:

• aromatic / tetramer of propylene 5.8 mole
• HF / propylene tetramer 1 by volume

Then the benzene and the alkylates in which the length of the branched alkyl chain is less than or equal to C ₁₂ are removed by distillation.

The sulfonation is carried out on the mixture of alkylates comprising, as indicated above, 80% of linear alkylate of reference and 20% of said heavy branched alkylate thus prepared.

EXAMPLE 4

• 80% en poids d'alkylat linéaire de référence
• et 20% en poids d'alkylat ramifié provenant de la réaction d'alkylation catalytique du benzène avec une composition oléfinique en moyenne en C₁₅ à C₁₈, obtenus lors de la fabrication de tétramère du propylène avec un seul réacteur, après étêtage du benzène et élimination par distillation des fractions légères correspondant à une chaíne alkyle inférieure à C₁₃.

The sulfonation is carried out on the following mixture of alkylates:

• 80% by weight of reference linear alkylate
• and 20% by weight of branched alkylate originating from the catalytic alkylation reaction of benzene with an olefinic composition with an average of C ₁₅ to C ₁₈ , obtained during the manufacture of propylene tetramer with a single reactor, after topping of the benzene and elimination by distillation of the light fractions corresponding to an alkyl chain lower than C ₁₃ .

EXAMPLE 5

• 80% en poids d'alkylat linéaire de référence
• et 20% en poids d'alkylat ramifié provenant de la réaction d'alkylation catalytique du benzène avec une composition oléfinique en moyenne en C₁₇ à C₁₈, obtenus lors de la fabrication de tétramère du propylène avec deux réacteurs d'alkylation en série, dont les conditions d'alkylation figurent dans le tableau ci-après.

The sulfonation is carried out on the following mixture of alkylates:

• 80% by weight of reference linear alkylate
• and 20% by weight of branched alkylate originating from the catalytic alkylation reaction of benzene with an olefinic composition with an average of C ₁₇ to C ₁₈ , obtained during the production of propylene tetramer with two alkylation reactors in series, the alkylation conditions of which are given in the table below.

Compared to Example 4, there are two differences intended to favor the increase in molecular mass: the first is an aliphatic chain longer in C ₁₇ to C ₁₈ than that in C ₁₅ to C ₁₈ of Example 4 and the second is a lower molar excess of benzene relative to the branched olefin than in Example 4, namely close to 1.5 stoichiometry, in a first reactor to promote, as far as possible, dimerization of the olefin either by formation of two alkyl substituents in the meta or para position or by alkylation of the dimer on the benzene. This alkylation reaction in the first reactor is followed by a reaction in a second reactor with a very large molar excess of benzene relative to the olefin, 10, to complete the alkylation of the aromatic carbide in question.

EXAMPLE 6

This example is identical to the previous example except that the 20% by weight of branched alkylate with an average olefin at C ₁₇ to C ₁₈ was obtained with a single catalytic alkylation reactor and a rate benzene molar to this 10 olefin.

EXAMPLE 7

This example according to the invention is identical to Example 5, of which it is distinguished on the one hand by the proportions of the alkylate mixture which are 50% - 50% and not more than 80% -20% and on the other hand by the absence of any addition of chloride ions to the corresponding sulfonate mixture.

EXAMPLE 8

In this example according to the invention, a mixture of 50% of linear alkylate of reference and 50% of an alkylate obtained by alkylation of benzene with a linear C ₁₂ olefin is used in a single reactor with topping of benzene and elimination alkylphenyl hydrocarbons substituted with a single C12 alkyl radical and the corresponding sulfonate mixture is analyzed without the addition of chloride ions.

EXAMPLE 9

This example differs from Example 7 only by the addition of ions chlorides in the form of calcium chloride.

Results of tests carried out on sulfonate mixtures corresponding result in compatibility of this mixture in a lubricating oil at the limit of acceptable, because there is a slight cloudiness when mixing with lubricating oil.

This example 9 shows the advantage of avoiding any addition of ions chlorides in mixtures of sulfonates according to the invention comprising between 50 and 75% of the linear monalkyl phenyl sulfonate a) and between 25 and 50% of an alkyl heavy aryl sulfonate b), as defined above.

COMPARATIVE EXAMPLE 10

In this example, only one alkylate was sulfonated, namely the alkylate heavy dialkyl-linear-phenyl type of Example 2.

It is found that the yield of the alkylation is less good and that the sulphonation rate has dropped practically by half, the content of HSO ₃ ^- of the sulphonic acid obtained passing from 14.4% in Example 2 to 8, 5% in Example 10.

COMPARATIVE EXAMPLE 11

In this example, sulfonation is performed only on the heavy branched alkylate corresponding to that used in Example 5 according to the invention.

COMPARATIVE EXAMPLE 12

In this example outside the invention, the sulfonation takes place only on the heavy branched alkylate described in Example 6 according to the invention.

COMPARATIVE EXAMPLE 13

In this example, the linear alkylate of reference, used at a rate of 80% by weight in the exemplary embodiments 1 to 6 of the present invention.

• un premier réacteur où le rapport molaire du benzène à l'oléfine linéaire en C₂₀ à C₂₄ est maintenue à 1,2 pour freiner la réaction d'alkylation en vue de favoriser la migration de la double liaison de l'oléfine des extrémités vers l'intérieur de la chaíne avant l'alkylation, et d'obtenir ainsi une teneur minimale en isomère 1- ou 2-phényle conforme à la présente invention et où le rapport volumétrique de l'acide fluorhydrique à l'oléfine est de 1 ; et
• un deuxième réacteur où on ajoute un large excès de benzène par rapport à l'oléfine et où on ajoute de l'acide fluorhydrique pour obtenir des rapports benzène/oléfine de 5,8 en moles et HF/oléfine de 2 en volume.

It will be recalled that, during the preparation of this alkylate, two catalytic alkylation reactors are used successively:

• a first reactor where the molar ratio of benzene to linear C ₂₀ to C ₂₄ olefin is maintained at 1.2 to slow down the alkylation reaction in order to promote the migration of the double bond of the olefin from the ends to inside the chain before alkylation, and thus obtain a minimum content of 1- or 2-phenyl isomer according to the present invention and where the volumetric ratio of hydrofluoric acid to olefin is 1; and
• a second reactor where a large excess of benzene is added relative to the olefin and where hydrofluoric acid is added to obtain benzene / olefin ratios of 5.8 by moles and HF / olefin of 2 by volume.

COMPARATIVE EXAMPLE 14

In this example, the sulfonation is carried out only on the heavy branched C ₁₅ -C ₁₈ alkylate used in Example 4, in order to determine the influence of the molecular mass.

Note that, as in Comparative Example 13, the sulfonate correspondent has a superficial skin which makes him unfit for his use as an additive for lubricating oil.

COMPARATIVE EXAMPLE 15

This is the same as Comparative Example 13 except that we use a single alkylation reactor with a benzene / olefin ratio of 10, which translated by an alkylate in which the molar ratio of the phenyl substituents in positions 1 and 2 in total of the phenyl substituents whatever its position is 0.20 instead of 0.093.

The consequences on the corresponding sulfonate are a lower lime incorporation (BN 14.5 instead of 19.4), viscosity stronger, a lower filtration speed and above all a more rapid skin formation with gel formation and poor compatibility, which makes the product unusable as a lubricant additive.

COMPARATIVE EXAMPLE 16

We tried to use an 80/20 mixture of alkylates comprising 80%, not of the reference alkylate used in Examples 1 to 9 according to the invention, but an alkylate obtained with a single alkylation reactor, where the benzene / linear C ₂₀ -C ₂₄ olefin ratio is 10, which results first of all in an alkylate having a substituent content in positions 1 and 2 of 0.20 molar. Such a content, reduced to 0.16 in the 80/20 mixture with 20% of a heavy alkylate, did not allow satisfactory tests to be obtained, as shown in particular by the formation of gel and superficial skin after one day and poor compatibility with the lubricating oil; whereas example 5 made from the same proportion in an 80/20 mixture but where the linear alkylate had a content in positions 1 and 2 of 0.093 molar had been found to have given good results.

Dispersion tests, carried out according to the spot test, as defined above, gave rise to the following results, which are also the subject of FIG. 3. Dispersion Foaming ASTM D - 892 Sequence I Composition of alkylates Spot test on the corresponding sulfonates Example Benzene / C 20-24 Benzene / propylene tetramer derivative C _17-18 13 100% - 372 0/0 5 80% 20% 369 0/0 9 50% 50% 366 0/0 11 - 100% 337 270/60

It follows from these data that the dispersion is better with a chemical mixture of the sulfonates according to the invention only with a mixture physics of each of the individual sulfonates in the same proportions.

Foaming tests were also carried out according to the standard method ASTM D-892 sequence I in which the higher the number is the lower, the better the product.

The results of these tests, which are indicated above with respect to Examples 5 and 9 according to the invention and Comparative Examples 11 and 13, confirm that at too high contents of branched alkyl benzene (Example 11), the Too high foaming makes the sulfonate unacceptable as an additive for lubricant and on the other hand that at the contents according to the invention (Examples 5 and 9) the sulfonates do not foam.

Claims (10)

1. Mixture of the superalkalinized alkyl-aryl-sulfonates of the alkaline earth metals, characterized in that it comprises:

   (a) at least 50% and at most 85% by weight of a mono-alkyl-phenyl-sulfonate in which the mono-alkyl substituent is a linear chain containing between 14 and 40 carbon atoms and the phenyl-sulfonate radical of an alkaline earth metal is attached, in a molar proportion of between 0 and 13%, preferably between 5 and 11% and more particularly between 7 and 10%, in the 1 or 2 position of the linear alkyl chain and

   (b) at least 15% and at most 50% by weight of a heavy alkyl-aryl-sulfonate chosen from:

   (i) the dialkyl-aryl-sulfonates in which the aryl radical may be a substituted or unsubstituted phenyl radical, such as in particular, phenyl, tolyl, xylyl, ethyl-phenyl or cumenyl radicals, and in which the two alkyl substituents are both linear alkyl chains of which the sum of the carbon atoms is between 16 and 40, preferably between 18 and 40 carbon atoms or

   (ii) the mono- or poly-alkyl-aryl-sulfonates in which the aryl radical may be a substituted or unsubstituted phenyl radical, such as in particular, phenyl, tolyl, xylyl, ethyl-phenyl or cumenyl radicals, and in which the alkyl substituent or substituents is/are branched chains, in which the sum of the carbon atoms is on average between at least 15 and up to 48 carbon atoms,

   the said mixture of alkyl-aryl-sulfonates having a maximum molar concentration of 10% and preferably less than or equal to 8% of linear monoalkyl-phenyl-sulfonate, in which the phenyl-sulfonate radical is substituted in the 1 or 2 position of the linear alkyl chain.
2. Mixture according to claim 1, characterized in that it comprises between 75 and 85% by weight of mono-alkylphenyl-sulfonates, as defined in (a) and between 15 and 25% by weight of the heavy alkyl-aryl-sulfonate as defined in (b) of the said claim 1.
3. Mixture according to either of claims 1 or 2, characterized in that the linear alkyl chain of the mono-alkyl-phenyl-sulfonate as defined in (a) of claim 1 contains between 16 and 30 and more particularly between 20 and 24 carbon atoms.
4. Mixture according to claim 1, characterized in that it comprises between 50 and 75% by weight of a monoalkyl-phenyl-sulfonate as defined in (a) and between 25 and 50% by weight of the heavy alkyl-aryl-sulfonate as defined in (b) of the said claim 1, the said mixture being free from chloride ions.
5. Mixture according to any one of claims 1 to 4, characterized in that the basicity index BN of the said mixture, as measured according to the ASTM-D-2896 standard, lies between 3 and 60 and preferably 10 and 40.
6. Application of the mixture of the superalkalinized alkyl-aryl-sulfonates of the alkaline earth metals according to any one of the preceding claims as a detergent-dispersant additive for lubricating oils.
7. Lubricating oil containing a mixture of superalkalinized alkyl-aryl-sulfonates of the alkaline earth metals according to any one of claims 1 to 5.
8. Method for preparing a mixture of superalkalinized alkyl-aryl-sulfonates of the alkaline earth metals according to any one of claims 1 to 5, characterized in that the mono-alkyl-phenyl hydrocarbons and the corresponding heavy alkyl-aryl hydrocarbons are mixed, the mixture of hydrocarbons is sulfonated and the resulting sulfonic acids are reacted with an excess of an alkaline earth base.
9. Method for preparing a mixture of superalkalinized alkyl-aryl-sulfonates of the alkaline earth metals according to any one of claims 1 to 5, characterized in that each of the alkyl-aryl-sulfonic acids is prepared separately, these are mixed and reacted with an excess of the base.
10. Method for preparing a mixture of superalkalinized alkyl-aryl-sulfonates of the alkaline earth metals according to any one of claims 1 to 5, characterized in that each of the alkyl-aryl-sulfonates entering into the composition of the mixtures is prepared separately and these are mixed in the required proportions.

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