EP0882116A1

EP0882116A1 - Mixture of earth-alkaline metal alkyl-aryl-sulphonates, its use as additive for lubricating oil and method of preparation

Info

Publication number: EP0882116A1
Application number: EP97938974A
Authority: EP
Inventors: Jean-Louis Le Coent
Original assignee: Chevron Chemical SA
Current assignee: Chevron Oronite SAS
Priority date: 1996-09-05
Filing date: 1997-09-03
Publication date: 1998-12-09
Anticipated expiration: 2017-09-03
Also published as: EP0882116B1; WO1998010044A1; JPH11514702A; DE69708848T2; CA2236318C; US6054419A; CA2236318A1; JP4112622B2; DE69708848D1; FR2752838B1; FR2752838A1

Abstract

The invention concerns a mixture of superalkalified earth-alkaline comprising: (a) 50 % to 85 % by weight of one mono-alkyl-sulphonate with a C14-C40 linear chain in which the molar ratio of phenyl-sulphonate substituent in position 1 or 2 is between 0 and 13 %, and (b) 15 % to 50 % by weight of one heavy alkyl-aryl-sulphonate, in which the aryl radical is phenyl substituted or not and the alkyl chains are either two linear alkyl chains with a total of 16 to 40 carbon atoms or one or several branched alkyl chains with an average total of 15 to 48 carbon atoms. Insofar as these mixtures contain less than 10 % of linear mono-alkyl-phenyl-sulphonate substituted in position 1 or 2 of the linear alkyl chain, they have properties enabling their use as washing-dispering additive for lubricating oils.

Description

Mixture of alkaline earth metal alkyl aryl sulfonates. its application as an additive for lubricating oil and preparation processes.

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

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

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 originate from the polymerization of propylene into C ₁₆ to C ₄₂ hydrocarbons, in particular the propylene tetrapolymer dimerized to a C ₂₄ olefin, and

- linear olefins which come from the oligo-polymerization of ethylene into C ₁₄ to C ₄₀ hydrocarbons.

However, if it is easy to obtain a good dispersion in the medium of the non-fixed alkaline earth base in the form of a salt when the sulphonic acid comes from a hydrocarbon obtained by aikylation of an aryl hydrocarbon with a branched olefin , it is not the same when this aikylation is carried out with a linear olefin, in particular containing at least 80 mol% 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, that is to say that 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 free lime content and in the absence of carbon dioxide and carbonate.

In fact, during the alkylation reaction with benzene or another aromatic or aryl hydrocarbon, the molar proportion of the corresponding hydrocarbon cyclic group in position 1 or 2 of the starting linear olefinic chain is approximately 25%.

However, this high proportion of alkylaryl hydrocarbon having in 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 OROGIL, the 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, a low calcium incorporation, a deterioration in anti-rust performance and the undesirable appearance. a cloudy appearance, or even a sedimentation, when the sulfonate thus prepared is added in an amount of 10% by weight to a standard lubricating oil and stored for examination. The Applicant has carried out chromatographic studies to identify each of the different isomers differing by the position of the aryl radical on the carbon atom of the linear alkyl chain and examined their respective influence on the properties of the corresponding alkyl-aryl-sulfonates of alkali metal- earthy obtained from these different isomers. It thus discovered that it could overcome the above drawbacks, insofar as the molar proportion of aryl hydrocarbon, other than benzene, attached to the 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 applicant.

However, it had not managed to obtain satisfactory results when the aryl hydrocarbon was benzene because it had never, until now, been able to avoid skin formation with the use of this aromatic hydrocarbon, even if this was alkyl with a linear mono-olefin of long chain length 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%. Following further studies, the Applicant has now discovered that the above-listed 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 straight chain, containing between 14 and 40 carbon atoms and the metal phenyl-sulfonate radical alkaline earth is fixed, in a molar proportion of 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 or the alkyl substituents 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 linear alkyl chain.

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 alkyl-aryl-sulfonate heavy as defined in (b), (i) or (ii) above with, for the mixture, the same maximum content of monoalkyl sulfonate substituted in position 1 or 2.

Indeed, said mixtures have a set of properties of solubility in lubricating oil, of filtration speed, of viscosity, of dispersion of impurities (carbonaceous particles), of incorporation of alkaline earth metal in the medium, of anti- rust, absence of cloudiness and 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 (linear) monoalkyl-phenyl-sulfonate, as defined in (a) above, that is to say obtained by aikylation of benzene with a linear olefin containing at least 80 mol% of linear mono-alpha-olefin, having a low BN basicity index (that is to say between 3 and 60), had hitherto never made it possible to obtain all of the properties necessary for their use as detergent-dispersant additives for lubricating oils.

The first of the two ingredients used in the composition of the mixtures forming the subject of the present invention, in a preponderant proportion 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 to obtain an ingredient making it possible to obtain a mixture having both a suitable improvement in the various properties listed above.

The content of 11% 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 abovementioned properties.

And that of 10% is the value sought during the industrial manufacture of the additive used in the composition of the mixture which is the subject of the present invention.

Without wishing 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, the more the hydrophobic character of the alkyl hydrocarbon. - corresponding phenyl is marked, hence the good properties of the mixtures of alkyl-phenyl-sulfonates according to the invention.

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

To achieve this, it is indeed necessary to add to it, 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% by weight. , compared to the mixture of sulfonates.

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

It can firstly 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 carbon atoms 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 in several ways.

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

A second process consists in a direct aikylation 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 corresponds to 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 benzene products (Linear Alkyl Benzene) in C ₁₂ , used commonly, after sulfonation and neutralization with soda, in household detergents. During its production, the linear C ₁₂ alkylbenzene is separated by distillation and the heavy fraction, called “LAB Bottoms”, consists mainly of dialkylbenzenes substituted in the 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 the 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 preceding ingredients, a straight chain, that is to say coming from the oligo-polymerization of ethylene, but branched chains, that is to say coming from the oligopolymerization of propylene, and in which the sum of the carbon atoms is on average at least 15 and up to 48 carbon atoms.

These heavy branched mono- or poly-alkyl-aryl sulfonates can be obtained by aikylation 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. 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-alkyl-aryl 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 oligopolymerization of the olefin branched used in the alkylation reaction.

The 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". During the manufacture of the latter, a large molar excess of benzene is alkylated by propylene tetramer and the heavy by-product is that which remains at the bottom of the column during the distillation at the top of the dodecyl-benzene. This heavy by-product consists essentially of a heavy monoalkyl-benzene where the number of carbon atoms in the branched alkyl chain is greater than or equal to 13 and of dialkyl-benzenes para and meta. As an indication, the molecular mass of dodecylbenzene is 242, while that of the heavy by-product obtained during 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 the mixtures of alkyl aryl sulfonates according to the present invention were not subject to the formation of a surface skin, to storage at room temperature, if their molar content of monoalkyl phenyl sulfonate in which the phenyl-sulfonate substituent substituted in position 1 or 2 on the linear alkyl radical is less than 10% and preferably equal to or less than 8%. The limit of 10% is the threshold beyond which skin formation appears within less than 48 hours after 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 superficial skin does not appear until after a storage time of several days, or even of one or more weeks, which makes them suitable as detergents. -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 particularly absorbs water and this absorption of water would lead to the harmful formation of a superficial skin during storage in the open air of the mixture containing it.

The invention also relates to processes for the preparation of such a mixture of alkyl-aryl-sulfonates.

A first process according to the invention comprises the mixture of the 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 process according to the invention comprises the separate preparation of each of the two alkyl-aryl-sulfonic acids, their mixing and their reaction with an excess of alkaline earth base.

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

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

To prepare the first alkyl phenyl sulfonate entering, in a preponderant proportion, in the mixtures according to the invention, the benzene is first alkylated with a linear olefin according to the Friedel and Craft reaction.

This alkylation reaction can be carried out either directly with a linear mono-olefin, already isomerized, containing a molar proportion of between 0 and 13%, preferably between 5 and 11% and more particularly between 7 and 10% of alpha. -olefin. It can also be carried out, if one starts from a linear alpha-olefin, not isomerized at the start, that is to say containing a conventional molar proportion of approximately 80% in alpha-olefin, by splitting the reaction d alkylation in two stages, namely a first stage, in which the molar ratio between benzene and the linear mono-olefin is at most 1.5 and preferably 1, and a second stage in which said ratio is at least 2 and preferably 5.

In either of the other alkylation processes, according to the Friedel and Craft reaction, an alkyl-phenyl hydrocarbon is obtained having 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 preferably chosen from hydrofluoric acid, aluminum chloride, boron fluoride, a sulfonic ion exchange resin or an acid-activated clay. 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 Applicant does not wish to be bound by any explanation, it would seem that the maintenance, at the start of the alkylation reaction, of a molar ratio of benzene to linear mono-alpha-olefin at most of 1.5 and preferably 1, in the presence of a Friedel and Craft catalyst, 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 found fixed.

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

The alkylation of this carbonium ion takes place according to an aromatic electrophilic substitution reaction where a hydrogen atom of benzene is substituted by a carbon atom of the linear olefinic chain. This isomerization reaction is unexpected since, until now, the highly exothermic alkylation reaction has always been carried out with a large molar excess of benzene relative to the starting linear olefin.

It should be noted, however, that this first isomerization step 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, in order to decrease the proportion of unreacted olefin and consequently increase the conversion rate of the starting linear olefin into 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 straight chain radicals or 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 carbon atoms 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 ₆ , C ₁₈ olefins, by C ₁₄ to C ₁₆ , C ₁₄ to C ₁₈ , C ₁₆ to C ₁₈ or C olefin sections. 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 peak significant in the regions of 908, 991 and 1.641 cm ^"1 , but which, on the other hand, shows the appearance of an absorption peak at 966 cm ^{" 1} , characteristic of an internal ethylenic double bond trans.

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 ₂ 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 content of alpha- 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 benzenic hydrocarbon, in particular to the exclusion of any alkyl derivative of benzene in which the aromatic nucleus is substituted by one or more two alkyl radicals C-- -C _5.

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

In the first reactor, the molar proportion of benzene relative to the linear olefin is at most 1.5 and preferably 1.2 and more particularly 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 hydrocarbon chain of the olefin.

In the second reactor, the molar proportion of benzene relative to the linear mono-alpha-olefin is increased to at least 2: 1 and, preferably, to 5: 1 and more, to complete the alkylation reaction.

And, at the end of the successive passage through the two reactors, the Friedel and Craft catalyst is collected by phase separation, and the excess benzene is recovered by distillation, as in the previous processes. The same alkylphenyl hydrocarbon can also be obtained by separately carrying out the isomerization of the starting alpha-olefin and then adding benzene to carry out the catalytic alkylation reaction, with a Friedel and Craft catalyst.

The alkylation reaction according to the Friedel and Craft reaction to obtain 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 products of reaction d '' an 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, i.e. 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 has an average of at least 15 carbon atoms.

The following step of sulfonation of each of the alkyl aromatic hydrocarbons or of the mixture of the various 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 d alkylation, with concentrated sulfuric acid, with an oleum, with sulfuric anhydride diluted in nitrogen or air or with sulfuric anhydride dissolved in sulfur dioxide. This sulfonation reaction can also be carried out by bringing the ingredients (alkylate and sulfuric anhydride) into contact in the form of a film falling in currents of the same or opposite directions. After the sulfonation, the acid or the various sulfonic acids obtained can be purified by conventional techniques, such as washing with water or by heat treatment with stirring with nitrogen bubbling (see for example the technique described in French patent No. 93 11709 of the applicant). The following stage of reaction of the acid or sulphonic acids with an excess of alkaline-earth base can be carried out by adding an oxide or a hydroxide of an alkaline-earth metal, such as magnesium, calcium or barium and especially lime.

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

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, mention may preferably be made of formic acid, acetic acid and their mixtures. Among the dilution oils which may be suitable in the neutralization stage, mention may be made of paraffinic oils such as 100 Neutral oil, as well as naphthenic or mixed oils.

After removal of the water and alcohol, it is filtered to remove the solids and the alkyl-aryl sulfonate (s) of alkaline earth metal obtained are collected. If the corresponding alkyl aryl hydrocarbons or the corresponding sulfonic acids have not already been mixed, the alkyl aryl sulfonates can be mixed at this stage in order to obtain the mixtures according to the invention in the desired proportions. The mixtures of alkyl aryl sulfonates according to the invention are preferably slightly over-alkalinized, that is to say that their basicity index BN, measured according to standard 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 advantageous, 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 alkyl phenyl sulfonates having such a basicity index, namely between 3 and 60 and preferably between 10 and 40 and coming exclusively from l alkylation of benzene, as detergent-dispersant additives for lubricating oil having satisfactory properties, and without the need to add calcium or ammonium chloride to reduce 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 any addition of chloride ions, notably in the form of calcium chloride or ammonium chloride, to satisfy all of the 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% by weight of said (linear) monoalkyl-phenyl-sulfonate, for which it is preferable to add chloride ions.

Indeed, until now, only alkyl-aryl-sulfonates from the alkylation of aryl hydrocarbons other than benzene or alkyl-aryl-sulfonates from the alkylation by branched olefins were considered necessary to present all 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 the 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, it can be added up to 1.7% by weight, for a diesel or marine engine oil, up to 3.5% by weight and finally for an oil of protection for new car, up to 11.5% by weight. The lubricating oils to which the mixtures according to the present invention can be added may be lubricating oils based on naphthenic, paraffinic or mixed; they can consist of mineral oils or come from products of distillation of coal or consist of synthetic oils, such as polymers of alkenes or esters of mineral acids or carboxylic acids.

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

In these examples, a number of test results are obtained, obtained by the following measurement methods:

Viscosity at 100 ° C in cSt

The viscosity is measured, at a temperature of 100 ° C., after diluting the sample of product to be measured in 100N oil, until a solution with a total calcium level of 2.35 is obtained. % in weight. When the product to be measured has a total calcium level of less than 2.35% by weight, the viscosity is then measured as it is according to the ASTM D-445 method.

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

This method is applicable to additives for lubricants.

An additive based on monosuccinimide, on zinc dithiophosphate and comprising approximately 75% by weight of the mixture of sulfonates to be tested is prepared, an additive which is placed in a 350 Neutral base oil.

The appearance of the solution is examined after 30 days at room temperature.

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

DISPERSION OF THE TASK)

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

It is generally applicable to terrestrial and marine engine oils. 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 minutes at 200 ° C without water Task N ° 3: 10 minutes 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, the diameter (d) of diffusion of the mixture is measured 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 of the 6 spots with the value found on one of the reference oils which will have to 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% under all conditions.

In the results of this test, the higher the number, the better the dispersibility of the 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, then the benzene is removed by topping, that is to say heating to 160 ° C. at atmospheric pressure.

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

The variables of the alkylation reaction are the following: (i) implementation in one or two reactors: - in the case of using a single reactor, 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 from 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 aikylation of benzene by a linear olefin in

C ₂₀ to C ₂ , a light fraction is not formed, 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.

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 is meant any alkyl benzene having an alkyl chain lower than C ₁₃ ; to remove 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, in which the molar proportion of the phenyl radical substituted on the carbon atoms in position 1 or 2 of the alkyl radical is determined relative 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 sulfur dioxide anhydrous 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 reactor 2 meters long and 1 cm in diameter into a co-current alkylate stream.

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, - alkylate flow rate between 350 and 450 g / h, depending on the desired SO ₃ / alkylate molar ratio 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 101 / h / kg of product and stirring at 85 ° C., until obtaining a lower residual content of H ₂ S0 ₄ (0.5% by weight maximum). The analyzes appearing in the table below relating to the 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 over-alkalization reaction used are those described in the aforementioned French patent application 2,564,830 from the company OROGIL, former name of the applicant, and published on November 29, 1985.

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

EXAMPLE 1

In this example, 80% by weight of a linear alkylate obtained by aikylation 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 aikylation 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 linear reference alkylate is mixed with 20% of a heavy alkylate of the linear dialkyl-phenyl type obtained in the following manner: 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 monoalkyl substituted phenyl hydrocarbon is transferred to

C ₈ in a second alkylation reactor where the same amount of HF is introduced as in the first reactor and linear alpha-olefin at C ₁₈ in the molar proportion of 3 moles of said substituted phenyl hydrocarbon per 1 mole of alpha - linear C ₁₈ 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 up to and including 18 carbon atoms. 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 mixture of alkylates defined above.

EXAMPLE 3

80% by weight of reference linear alkylate and 20% by weight of a branched heavy alkylate obtained as follows are mixed:

In a first reactor, the catalytic alkylation of the benzene is carried out with propylene tetramer with a benzene / propylene tetramer molar ratio of 1.2 and an HF / propylene tetramer ratio of 1 by 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 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 reference alkylate and 20% of said branched heavy alkylate thus prepared.

EXAMPLE 4 The sulfonation is carried out on the following mixture of alkylates:

- 80% by weight of linear alkylate of reference

- and 20% by weight of branched alkylate originating from the catalytic alkylation reaction of benzene with an olefinic composition on average of C ₁₅ to C _1β , obtained during the manufacture of propylene tetramer with a single reactor, after topping of the benzene and elimination by distillation of light fractions corresponding to an alkyl chain lower than C ₁₃ .

EXAMPLE 5

The sulfonation is carried out on the following alkylate mixture: - 80% by weight of linear reference alkylate

- and 20% by weight of branched alkylate originating from the catalytic alkylation reaction of benzene with an olefinic composition on average at 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 promote the increase in molecular mass: the first is a longer aliphatic chain in C ₁₇ to C ₁₈ than that in C ₁₅ to C ₁₈ of Example 4 and the second is a smaller molar excess of benzene relative to the branched olefin than in Example 4, namely close to stoichiometry 1, 5, in a first reactor to promote, as far as possible, the dimerization of the olefin either by formation of two alkyl substituents in eta or para position or by aikylation of the dimer on 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, from which it is however 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 in the mixture of corresponding sulfonates.

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 aikylation 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 chloride ions in the form of calcium chloride. The results of the tests carried out on the corresponding sulfonate mixtures are reflected in the compatibility of this mixture in a lubricating oil to the limit of acceptable, since there is the appearance of a slight haze when mixed with the lubricating oil. This example 9 shows the advantage of avoiding any addition of chloride ions in the mixtures of sulfonates according to the invention comprising between 50 and 75% of the linear monalkylphenyl sulfonate a) and between 25 and 50% of an alkyl aryl sulfonate. heavy b), as defined above.

COMPARATIVE EXAMPLE 10

In this example, a single alkylate was sulfonated, namely the heavy alkylate of dialkyl-linear-phenyl type from 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 HSO ₃ ^"content of the sulphonic acid obtained passing from 14.4% in Example 2 to 8, 5% in Example 10. COMPARATIVE EXAMPLE 11

In this example, the sulfonation is carried out 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 is carried out only on the heavy branched alkylate described in Example 6 according to the invention.

COMPARATIVE EXAMPLE 13

In this example, the reference linear alkylate was exclusively sulfonated, used in an amount of 80% by weight in embodiments 1 to 6 of the present invention. 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 towards the inside of the chain before alkylation, and thus obtaining 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 mole 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.

It will be noted that, as in Comparative Example 13, the corresponding sulfonate has a surface skin which renders it unsuitable for use as an additive for lubricating oil.

COMPARATIVE EXAMPLE 15

It is the same as Comparative Example 13 except that a single alkylation reactor is used with a benzene / olefin ratio of 10, which results in an alkylate in which the molar ratio of the phenyl substituents in the 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 incorporation of lime (BN of 14.5 instead of 19.4), a higher viscosity, a lower filtration speed and above all a more rapid skin formation with gel formation and poor compatibility, making 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 ₂ oC ₂₄ olefin ratio is 10, which first results 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.

Foaming Dispersion

Composition of alkylates Spot test on ASTM D - 892

Example Benzene / C Benzene / tetramer derivative sulfonates Sequence I e 20-24 of propylene C ₁₇ . ₁₈ penpals

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 than with a physical mixture of each of the individual sulfonates in the same proportions.

Foaming tests were also carried out according to the standardized method ASTM D-892 sequence I in which the lower the number, 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.

BOARD

SAI 1 2 3 4 5 6

LATION îtique Benzene Benzene Benzene Benzene Benzene Benzene Benzene Benzene Benzene Benzene Benzene Benzene e linear C20-24 C20-24 C8 / C18 C20-24 C20-24 C20-24 C20-24

propylene tetramer C12 C12 C15-18 C17-18 C17-18

ALKYLATION HORS HF HF HF HF HF HF HF HF HF HF HF HF

TEUR 1 tick / olefin (mol) 1, 2 10 1, 2 1 1, 2 1, 2 1, 2 10 1, 2 1, 5 1, 2 | 10 c TEUR 2 total tick / olefin (mol) 5.8 5.8 3 5.8 l 5.8 5.8 5.8 10 5.8 m σ ITIONS OBTAINING Topping Topping Topping Topping Topping Topping Topping Topping Topping Topping Topping Elimination Topping Elimination m .LKYLAT benzene bz + light benzene bz + light benzene bz + light benzene bz + light benzene bz + light benzene bz + light

("SE FROM ALKYLAT m

S Position 1 + 2 (mol) 0.093 0.093 0.093 0.093 0.093 0.093 -o ∑ ite positions at 40 ° C (cSt) 17 35 17 25 17 16.5 17 17 17 49 17 27.5

O alkylate 80 20 80 20 80 20 80 20 80 20 80 20

3 m ^ TERISTICS OF THE MIXTURE OF ALKYLATES, ACIDS AND SULFONATES CORRESPONDING

'SE DE L'ALKYLAT position 1 + 2 (mol) 0.074 0.074 0.074 0.074 0.074 0.074

30 m positions for the 2 alkylates O 'SE OF ACID rm ⁾ ₃ ^" (weight) 12.8 14.4 15.3 15.8 14.5 15.2

I D → (weight) 0.2 0.3 0.27 0.24 0.17 σ> 0.1 1

SULFONATE u without CaCI ₂ WITH WITH WITH WITH WITH WITH WITH

(weight) 2.35 2.6 2.63 2.56 2.56 2.6

(weight) 1.6 1, 76 1, 74 1, 8 1, 89 1, 76

896) 17 19.8 19.7 17.7 17.9 20 t at 100 ° C at 2.35 Ca (cSt) 30 18.4 21, 8 80 36 35.5 nents gross (vol) 0.6 0.4 0.6 0.6 0.6 1 filtration (Kg / H / m ² ) 1200 3350 240 480 790 1350 oz of skin in the open air 5 days 7 days 1 month 1 month 7 days 7 days ibi tee GOOD GOOD GOOD GOOD GOOD GOOD

TABLE (continued 1)

TABLE (continued 2)

TEST NO. 10 11 12 | 13 14 15 16

ALKYLATION

Aromatic Benzene Benzene Benzene Benzene Benzene Benzene Benzene Benzene

Linear olefin C8 / C18 C20-24 C20-24 C20-24

Propylene tetramer derivative C17-18 C17-18 C15-18 C17-18

Catalyst HF HF HF HF HF HF HF HF

REACTOR 1

Aromatic / olefin (mol) 1 1, 5 10 1, 2 10 10 10 1, 5

- mπ REACTOR 2 c Total aromatic / olefin (mol) 3 10 5.8 10

CONDITIONS TO OBTAIN Elimination Elimination Elimination Topping Topping Elimination Topping Topping Topping Elimination m ALKYLAT bz + light bz + light bz + light benzene bz + light benzene benzene bz + light σ m ANALYSIS OF ALKYLAT

30 Position 1 + 2 (mol) 0.093 0 20 0.2 m ∑ positions

Viscosity at 40 ° C (cSt) 25 49 27.5 17 17 18 18 49

% weight of alkylate 100 100 100 100 100 100 80 20 20

O CHARACTERISTICS OF THE MIXTURE OF ALKYLATES, CORRESPONDING ACIDS AND SULFONATES m

3 ALKYLAT ANALYSIS m z position 1 + 2 (mol) 0.093 0.20 0.16

H ∑ positions for the 2 alkylates

ACID ANALYSIS m% HSθ ₃ ^" (weight) 8.5 10.5 15 15.4 17.3 14.6 14.2 Ω r-% H ₂ S0 ₄ (weight) 0.3 0.35 0 , 1 0.18 0 1 0.2 0.2 m ro ANALYSIS OF SULFONATE

With or without CaCI ₂ WITH WITH WITH WITH WITH WITH WITH WITH

% CaT (weight) 2.67 2.66 2.4 2.64 2.59 2.35 2.45

% CaS (weight) 1.74 1.78 1.74 1.83 1.76 1.75 1.71

BN (D2896) 21, 9 18 23 19.4 19 14.5 17.2

Viscosity at 100 ° C at 2.35 Ca (cSt) 22 30 103 46.4 97 100 52

% raw sediment (vol) 0.6 0.12 0.6 0.6 0.6 1.2 0.8

Filtration speed (Kg / H / m *) 15,500 250,710,545 30,208

Skin formation in the open air no skin 3 days 3 days 1 day gel 1 day 10 hours gel 1 day

Compatibility BAD BAD BAD BAD BAD BAD BAD

Claims

1. Mixture of alkaline earth metal alkali-aryl sulfonates, characterized in that it comprises (a) at least 50% and at most 85% by weight of a mono-alkylphenyl sulfonate in which the substituent mono-alkyl is a linear chain, containing between 14 and 40 carbon atoms and the phenyl-sulfonate radical of alkaline earth metal is fixed, in a molar proportion ranging 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:

(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 mono-alkylphenyl-sulfonate, in which the phenyl-sulfonate radical is substituted in position 1 or 2 of the linear alkyl chain.

2. Mixture according to claim 1 characterized in that it comprises between 75 and 85% by weight of mono-alkyl-phenyl-sulfonates such as defined in (a) and between 15 and 25% by weight of the heavy alkyl-aryl sulfonate as defined in (b) of said claim 1.

3. Mixture according to any one 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 monoalkyl-phenyl-sulfonate as defined in (a) and between 25 and 50% by weight of the alkyl-aryl- heavy sulfonate as defined in (b) of said claim 1, said mixture being free of chloride ions.

5. Mixture according to any one of claims 1 to 4, characterized in that the basicity index BN of said mixture, as measured according to standard ASTM-D-2896, is between 3 and 60 and preferably 10 and 40.

6. Application of the mixture of alkyl-aryl sulfonates of alkaline earth metal alkalinized according to any one of the preceding claims as detergent-dispersant additive for lubricating oils.

7. Lubricating oil containing a mixture of alkyl-aryl-sulfonates of alkaline earth metal alkalinized, according to any one of claims 1 to 5.

8. A process for the preparation of a mixture of alkaline earth metal alkaline earth metal sulfonates according to any one of claims 1 to 5, characterized by the mixture of the corresponding mono-alkyl-phenyl and heavy alkyl-aryl hydrocarbons , the sulfonation of the hydrocarbon mixture and the reaction of the resulting sulfonic acids with an excess of alkaline earth base.

9. A process for the preparation of a mixture of alkaline earth metal alkali earth sulfonates according to any one of the claims 1 to 5, characterized by the separate preparation of each of the alkyl aryl sulfonic acids, their mixing and their reaction with an excess of base.

10. A process for the preparation of a mixture of alkaline earth metal alkaline earth metal sulfonates according to any one of claims 1 to 5, characterized by the separate preparation of each of the alkyl aryl sulfonates used in the composition mixtures and their mixing in the required proportions.