EP0086141A1 - Process for the preparation of organo-soluble complexes of calcium, complexes obtained and their use, e.g. as additives for improving the burning of gas oils and fuel oils - Google Patents

Abstract

A process for the preparation of organosoluble calcium complexes for use as combustion additives in liquid fuels is described, which comprises: (a) reacting a sulfonic acid with excess calcium oxide or hydroxide , in a mixture of solvents comprising a liquid hydrocarbon of petroleum origin or a halogenated hydrocarbon as well as isopropanol and methanol, in the presence of a nitrogen-containing compound with a long hydrocarbon chain; and (b) carbonating most of the excess calcium oxide or hydroxide with carbon dioxide. Additives are obtained, the calcium content of which can range up to about 20 gram atoms of calcium per gram equivalent of sulfonic acid. The improvement brought about by the implementation of the process of the invention can also be applied to the preparation of calcium solfonates with a high basicity reserve used as detergent-dispersant additives in lubricating oils.

Description

The invention relates to an improved process for the preparation of organosoluble calcium complexes, which can be used in particular as additives which improve the combustion of liquid fuels. It also relates to the complexes obtained by this process and their uses.

The combustion of liquid hydrocarbons such as for example gas oils, fuel oil, light fuels, heavy fuels, or even kerosene, leads, even under the best economically feasible conditions, to the more or less significant emission of unburnt substances , liquid or gaseous solids, such as soot, cracked hydrocarbons, carbon monoxide, as well as nitrogen oxides. The main disadvantages of these unburnt products are that they reduce the efficiency of the energy generators (fuel oil burners, diesel engines, etc.), due to the loss of combustible material and the formation of deposits (especially soot) on the exchangers. heat, which results in a decrease in heat transfer coefficients; and lead to the emission of harmful fumes, which should be reduced as much as possible. Attempts are generally made to remedy these drawbacks by incorporating into liquid fuels (diesel or fuel oils for example) organosoluble compounds of iron, calcium or barium for example, having the effect of preventing the emission of smoke, or at least reduce its importance. These compounds act by catalytic effect to ensure more complete combustion of the fuels and thus make it possible in particular to reduce the weight of solid combustion residues.

It has now been discovered that it is possible to prepare organosoluble calcium complexes which have an increased calcium content compared to the content of organosoluble calcium complexes obtained by the methods described in the prior art.

For the preparation of calcium sulfonic complexes, a process has indeed been found in which it is possible to use only reduced molar proportions of the organic binder used (hydrocarbyl sulfonic acid). This process is advantageous in particular in the case where it is desired to use as raw material an alkylbenzene sulfonic acid of relatively high molecular weight, for example of the order of 400 to 500, sulfonic acids of this type not allowing obtaining very high calcium contents when the preparation methods described in the prior art are used.

• (a) la mise en réaction d'un acide sulfonique aliphatique, alicy- clique ou aromatique avec de l'oxyde ou de l'hydroxyde de calcium en excès (par rapport à la quantité correspondant à la formation du sulfonate de calcium basique) au sein d'un milieu liquide comprenant d'une manière générale une huile minérale de dilution, un solvant hydrocarboné ou halogèno-hydrocarboné ainsi que du méthanol'et un monoalcool en C₃ ou C₄ en présence d'un composé à fonctions azotées et à longue chaîne hydrocarbonée ;
• (b) la mise en contact du mélange réactionnel résultant de l'étape (a) avec une quantité d'anhydride carbonique nécessaire pour carbonater une proportion substantielle de l'excès d'oxyde ou d'hydroxyde de calcium, et
• (c) la séparation du complexe de calcium formé, obtenu en phase organique.

In general, the organosoluble complexes considered in the invention result from a process which comprises:

• (a) reacting an aliphatic, alicyclic or aromatic sulfonic acid with excess calcium oxide or hydroxide (relative to the amount corresponding to the formation of basic calcium sulfonate) to within a liquid medium generally comprising a mineral dilution oil, a hydrocarbon or halogeno-hydrocarbon solvent as well as methanol 'and a C ₃ or C ₄ monoalcohol in the presence of a compound with nitrogen functions and with long hydrocarbon chain;
• (b) bringing the reaction mixture resulting from step (a) into contact with an amount of carbon dioxide required to carbonate a substantial proportion of the excess calcium oxide or hydroxide, and
• (c) separation of the calcium complex formed, obtained in the organic phase.

The process thus defined makes it possible, in particular thanks to the simultaneous use of methanol and of the second alcohol In particular proportions which will be indicated below, to obtain sulfonic complexes having a very high calcium content. A particularly important operating advantage lies in the fact that the process takes place within a single liquid phase, the reaction water being kept in solution by the presence of the second alcohol; on the contrary, in the absence of this alcohol, the he appearance of a hydro-alcoholic phase very significantly disturbs the course of carbonation.

In the first step of the process of the invention, first of all, a sulfonic acid is used, which can be aliphatic, alicyclic or aromatic. It will most often be an aromatic sulfonic acid.

As examples of aromatic sulfonic acids, mention may be made of alkylbenzene sulfonic acids which contain from about 10 to 20 carbon atoms. Mention may also be made of industrial alkylbenzene sulfonic acids (so-called "heavy alkylbenzene sulfonic acids") which contain from about 20 to 35 carbon atoms.

As indicated above, a minor proportion of at least one compound containing nitrogen functions and at least one long hydrocarbon chain is also brought into play, this compound having the effect of allowing better solubilization of the sulfonic complex in the hydrocarbon medium.

et

dans lesquelles R représente un radical hydrocarboné aliphatique substantiellement saturé renfermant de 20 à 250 atomes de carbone,de préférence de 75 à 100, X représente un radical alkylène de 2 à 5 atomes de carbone dont les deux valences sont situées sur des atomes de carbone distincts, et m prend une valeur de 1 à 5, de préférence de 1 à 3.The compound with nitrogen functions and with long hydrocarbon chain (s) can consist in particular of a polyalkenylsuccinimide-amine or a bis (polyalkenylsuccinimide) -amine corresponding respectively to the general formulas:

and

in which R represents a substantially saturated aliphatic hydrocarbon radical containing from 20 to 250 carbon atoms, preferably from 75 to 100, X represents an alkylene radical of 2 to 5 carbon atoms, the two valences of which are located on separate carbon atoms , and m takes a value from 1 to 5, preferably from 1 to 3.

Among these compounds, there may be mentioned more particularly those in which the radical R results from the polymerization or copolymerization of one or more light olefins having for example from 2 to 6 carbon atoms, such as for example ethylene, propylene butenes -1 and -2, isobutene or methyl -2 pentene-1. The radical R can be, more specifically, a polyisobutenyl radical having a molecular mass of approximately 900 to 1300. The radical X is most often the ethylene radical -CH ₂ - CH ₂ - and n takes for example the value 3.

In this particular case, the preparation of polyalkenylsuccinimide-amine or bis (polyalkenylsuccinimide) -amine brings into play polyisobutenyl succinic anhydride and tetraethylenepentamine at a rate of 1 (or 2) mole (s) of anhydride per mole of tetraethylenepentamine .

The operating procedure for the preparation of (bis) polyalkenylsuccinimide-amines is well known in the art: it is described in particular in French patents 1,265,085 and 1,422,401.

où R¹ représente un radical hydrocarboné monovalent (par exemple aliphatique) qui renferme de 6 à 22 atomes de carbone, n prend une valeur entière de 0 à 4 et p, nul lorsque n est nul, prend la valeur 0, 1, ou 2 lorsque n est différent de zéro.As other compounds with nitrogen functions and with a long hydrocarbon chain, mention may also be made of the amino acids corresponding to the general formula:

where R ¹ represents a monovalent hydrocarbon radical (for example aliphatic) which contains from 6 to 22 carbon atoms, n takes an integer value from 0 to 4 and p, zero when n is zero, takes the value 0, 1, or 2 when n is different from zero.

où R¹ est défini comme ci-dessus et peut être par exemple un mélange de radicaux alkyles de 12 à 14 atomes de carbone.Among these compounds, there may be mentioned more particularly those which correspond to the formulas:

where R ¹ is defined as above and can for example be a mixture of alkyl radicals of 12 to 14 carbon atoms.

The compound with nitrogen functions and with long hydrocarbon chain (s) is generally introduced into the reaction medium in a proportion of 10 to 30% by mass and preferably of 15 to 25% by mass relative to to the engaged sulfonic acid.

The reaction medium advantageously comprises a dilution oil which generally consists of a mineral oil of low viscosity. like for example a 100 Neutral Solvent oil. The mass proportion of this oil with respect to sulfonic acid generally corresponds to a ratio ranging from about 1: 5 to 2: 1.

The implementation of the process of the invention requires the use of a hydrocarbon or halogeno-hydrocarbon solvent, consisting more particularly of an aromatic hydrocarbon such as for example benzene, toluene, xylene, mono or di- ethylbenzene or mono- or di-isopropylbenzene; or an aliphatic hydrocarbon halogenated such as for example trichlorethylene. Various petroleum fractions can also be used, such as gas oils or domestic fuel oils.

When it is desired to obtain the organosoluble calcium complex according to the invention, in the form of a solution, it is advantageous to use a solvent which has a boiling point high enough not to be eliminated under the operating conditions. of the final stage of obtaining the additive as they will be defined below. Solvents of this type are for example diisopropylbenzene, gas oils or domestic fuel oils.

The hydrocarbon or halo-hydrocarbon solvent thus defined is generally used in a proportion ranging from 1 to 10 kg per kilogram of sulfonic acid.

The C ₃ or C ₄ monoalcohol is preferably isopropanol.

C ₃ or ^C ₄ / Methanol and monoalc ^ool / are generally introduced in a total proportion ranging from 80 to 1000 ml per liter of hydrocarbon or halogen-hydrocarbon solvent. The volume ratio of C ₃ or C ₄ alcohol to methanol is at most 3.5: 1. It can be as small as, for example 1: 100, but the preferred values are in the range of 1.5: to 3: 1.

In carrying out the process of the invention, calcium oxide is introduced into the reaction medium in excess relative to the stoichiometry of basic calcium sulfonate (which corresponds to 1 gram atom of calcium per gram equivalent of sulfonic acid). Thus, according to the proportion of calcium which it is desired to introduce into the complex, and taking into account the yield of the subsequent carbonation step, the proportion of calcium oxide or hydroxide used may range from 1 to 30 atoms- gram of calcium per equivalent gram of sulfoni ^q ue acid.

In general, calcium hydroxide (or "slaked lime") is used.

To carry out the first step of the process of the invention, the reaction mixture constituted as described above is heated to a temperature of 20 to 65 ° C (preferably of the order of 55 to 60 ° C), with vigorous stirring, so as to achieve the neutralization of sulfdnic acid.

In the second step of the process for the preparation of the sulfonic complexes of the invention, carbonation is carried out of a substantial proportion, and preferably as much as possible, of the excess oxide or hydroxide dispersed at within the reaction mixture. Carbonation is generally carried out using gaseous carbon dioxide, pure or diluted by an inert gas with respect to the reactants present, in very divided form, the reaction mixture being kept, always with stirring, at a temperature from 20 to 65 ° C, and preferably between 55 to 60 ° C.

The liquid obtained contains the unreacted oxide or hydroxide in suspension, the carbonation yield cannot be total. The carbonation yield decreases when an increasing excess of oxide or hydroxide is involved.

The magnitude of this excess should be determined so as to introduce the optimum proportion of metal into the complex, without having to remove too much of the unreacted oxide or hydroxide.

The volatile constituents of the mixture obtained (water, methanol, isopropanol, toluene, benzene, chlorinated solvent, etc.) are removed, for example, by evaporation under reduced pressure in a rotary thin layer evaporator. Solid particles of unreacted metal oxide or hydroxide are removed, for example by filtration or centrifugation.

When the hydrocarbon solvent is volatile, the additive obtained under the conditions described is in the form of a glassy solid, however, entirely soluble in petroleum hydrocarbons.

In the case where the solvent used is a heavy hydrocarbon (for example diisopropylbenzene or a gas oil), the organosoluble complexes of the invention are collected in the form of a very fluid clear liquid. dilution possibly introduced at the start.

The use of a determined proportion of heavy hydrocarbon solvent makes it possible to obtain solutions of organo-soluble complex which, in general, for reasons of convenience of use, have a metal content of approximately 10% by mass. The quantity of complex solution obtained generally represents a very high percentage of the quantity which it was theoretically possible to obtain (of the order of 85 to 95%).

The organosoluble calcium complexes obtained by the process of the invention can contain very high calcium contents. Thus, the proportion of calcium introduced can range from 5 to 20 gram atoms of calcium per gram equivalent of sulfonic acid.

These organosoluble calcium complexes can be used as additives for improving the combustion of various liquid fuels (gas oils, fuel oils). They are then added to these fuels in a proportion which can range, for example, from 10 to 150 ppm, preferably from 25 to 75 ppm, by mass of calcium relative to the mass of the liquid fuel.

The substantial improvement brought to the preparation of organosoluble calcium complexes by the implementation of the process of the invention can also be applied to the preparation of calcium sulfonates with high basicity reserve used as detergent-dispersant additives in lubricating oils.

in C ₃ or ^C ₄₁ The simultaneous use of methanol and an alcohol / in the relative proportions mentioned above constitutes a marked improvement in the processes described in particular by the applicant in the French patents 2,236,001 & 2,265,848, and in the certificate of addition 2,271,281 referring to patent 2,265,848. It should be understood that the content of these patents and certificate of addition is included here by the reference which is made there.

The following examples illustrate the invention, but they must in no way limit its scope to the particular practical embodiments described therein. Examples 3, 4, 6 to 10 and 13 are given for comparison.

In all the examples, the total basic index of the products (denoted TBN) was determined according to standard ASTM D 664-58.

EXAMPLE 1

• - 312,5 g d'un acide alkylbenzène sulfonique lourd de synthèse (ayant une masse molaire équivalente, compte tenu d'une teneur en insulfonés de 30 % en poids, voisine de 700 g) soit 0,45 mole d'acide ;
• - 70 g d'une bis (polyalkénylsuccinimide)-amine, de formule générale
  
  où R est un radical polyisobutènyle de masse moléculaire de 120C à 1300 ; le groupement polyamine étant obtenu à partir de tétraéthylènepentamine. Le produit commercial, dont le TBN est de 20,consiste en une solution à 50 % en masse de cette amine dans une huile lubrifiante de base de faible viscosité.
• - 114,5 g d'une huile minérale 100 Neutral Solvent
• - 1000 ml de diisopropylbenzène
• - 180 ml d'alcool isopropylique absolu
• - 60 ml d'alcool méthylique absolu
• - 446 g de chaux éteinte pure exempte de carbonate.

In a 2 1 glass reactor, fitted with a double jacket, a vigorous stirring device, a tube with a porous tip allowing the introduction of very divided gas, a thermometer and an electrode coaxial glass / calomel, we successively introduce:

• - 312.5 g of a synthetic heavy alkylbenzene sulfonic acid (having an equivalent molar mass, taking into account an insulfone content of 30% by weight, close to 700 g), ie 0.45 mole of acid;
• - 70 g of a bis (polyalkenylsuccinimide) -amine, of general formula
  
  where R is a polyisobutenyl radical of molecular mass from 120C to 1300; the polyamine group being obtained from tetraethylenepentamine. The commercial product, the TBN of which is 20, consists of a 50% by mass solution of this amine in a low-viscosity base lubricating oil.
• - 114.5 g of 100 Neutral Solvent mineral oil
• - 1000 ml of diisopropylbenzene
• - 180 ml of absolute isopropyl alcohol
• - 60 ml of absolute methyl alcohol
• - 446 g of pure slaked lime free of carbonate.

Via the heat transfer fluid circulating in the jacket, the temperature of the mixture is brought to 50 ° C while ensuring vigorous stirring.

Using the gas distributor tube, placed within the suspension and just below the agitator, 111.3 1 of CO ₂ (4.64 mole or 204 g) are then introduced over 4 hours, all keeping the reaction temperature between 55 and 60 ° C.

• La solution brune obtenue, contenant l'excès de chaux, est transférée dans un évaporateur rotatif en couche mince où elle est débarassée de ses constituants volatils (eau, alcools) par évaporation sous pression réduite (110°C, 30 mmHg).La suspension chaude ainsi obtenue est transférée dans un filtre monoplaque du type GAUTHIER (surface filtrante : 113 cm²), puis filtrée en une heure environ sous une pression effective de 2 bars. On recueille ainsi l100 g de solution organique limpide très fluide constituant l'additif, soit environ 60 % en masse de la quantité théorique.

The pH of the mixture is monitored as a function of the% of C0 ₂ introduced:

• The brown solution obtained, containing the excess lime, is transferred to a thin layer rotary evaporator where it is freed from its volatile constituents (water, alcohols) by evaporation under reduced pressure (110 ° C, 30 mmHg). hot thus obtained is transferred into a single-plate filter of the GAUTHIER type (filtering surface: 113 cm ² ), then filtered in about one hour under an effective pressure of 2 bars. 1100 g of clear, very fluid organic solution constituting the additive are thus collected, ie approximately 60% by mass of the theoretical quantity.

The filter cake is dispersed with twice 500 cm ³ of hexane, the suspension obtained being again filtered under 2 bars.

The filtrates recovered are combined and then evaporated under 30 mmHg at 120 ° C; finally collecting 1737 g of an additive titrating 10% by mass of calcium, which represents 95% by mass of the theoretical amount of additive that can be obtained.

The additive thus collected has the following physicochemical characteristics:

EXAMPLE 2

the same experiment as in Example 1 is carried out by replacing diisopropylbenzene with the same volume of a light petroleum solvent: toluene.

After carbonation, the suspension is transferred to the GAUTHIER filter, where it is filtered in approximately 1 hour under an effective pressure of 2 bars. After having washed the filter cake twice with 500 cm 3 of hexane, the collected filtered hydrocarbon fractions are stripped of their volatile constituents in the rotary thin layer evaporator (reaction water, alcohols, toluene). 915 g of an additive are thus recovered which is presented at room temperature in the form of a very viscous translucent liquid, completely soluble in petroleum hydrocarbons and which represents approximately 93.5% by mass of the theoretical amount. additive obtainable.

The additive thus collected has the following characteristics:

The high value of the measured TBN indicates a content of calcium carbonate in the colloidal state of the order of 48.1% of the total mass of additive, and an amount of calcium sulfonate of approximately 24.6%; which means that the ratio of the number of calcium atoms to the number of acid molecules contained, is of the order of 10.7, or that the ratio of the number of calcium atoms, in the form of colloidal carbonate, to the number of calcium atoms in the form of sulfonate, is around 21.3.

EXAMPLE 3 (comparative)

The same experiment as in Example 1 is carried out by replacing methyl alcohol with the same volume of pure isopropyl alcohol, ie a total volume of this alcohol of 240 cm ³ (total absence of methyl alcohol).

It is observed that the carbonation of the lime ceases as soon as only 10% of the amount of C0 ₂ provided has been introduced into the reaction medium. The suspension obtained, with a milky appearance, turns out to be practically impossible to filter under 2 bars.

EXAMPLE 4 (comparative)

The same experiment as in Example 1 is carried out by replacing isopropyl alcohol with the same volume of methyl alcohol, ie a total volume of this alcohol of 240 cm ³ (total absence of isopropyl alcohol).

After carbonation and evaporation of the volatile constituents, after 14 hours of filtration under 2 bars, only 1422 g of an additive solution titrating 10.8% by mass of calcium is recovered.

EXAMPLE 5

The same experiment as in Example 1 is carried out by replacing diisopropylbenzene with the same volume of engine diesel. Finally recovered and under these conditions 1744 g of a solution containing 9.75% by mass of calcium or about 95.4% by mass of the theoretical amount of additive that can be obtained.

EXAMPLES 6 to 11

Various experiments are carried out under the conditions of Example 1, using mixtures of methyl and isopropyl alcohols in various proportions.

The results of Examples 1 to 11 are collated in Table I.

It is noted in particular that in Example 3, the isopropanol used in the same proportion as the mixture of alcohols of Example 1 is unsuitable for the carbonation of lime.

It is further observed that in Example 4, the replacement of isopropanol by methanol allows the carbonation of lime but that this reaction is not carried out under conditions as satisfactory as that carried out in Example 1 in the presence of the mixture of the two alcohols, as evidenced by the excessive duration of the filtration and the low yield obtained.

If we reproduce Examples 1 and 4 leaving the mixtures at rest after carbonation, we observe, after centrifugation, the appearance of two liquid phases with the suspension obtained in Example 4, against only one in Example 1. The chromatographic analysis of the colorless supernatant phase recovered shows that it is essentially composed of methanol and water.

It therefore appears in Example 1 that the best carbonation conditions are the fact that the reaction water is kept in solution by the presence of isopropyl alcohol which acts as a compatibilizing agent.

Example 3 shows, however, the essential nature of the presence of methanol in the medium, since isopropanol alone does not allow the operation to be carried out successfully.

EXAMPLE 12

The same experiment as in Example 2 is carried out with the following amounts of reagents:

The carbonation is carried out by introducing 210 g of C0 ₂ (4.77 moles) over 4 hours under the temperature conditions described above. Finally recovering 520 g of additive representing about 65% by mass of the theoretical amount that can be obtained. The additive collected under these conditions is in the form of an extremely viscous liquid at room temperature, but nevertheless fluid and easily handled at 100 ° C; Its solubility in petroleum hydrocarbons is total.

Its physico-chemical characteristics are as follows:

The high value of the measured TBN indicates a content of calcium carbonate in the colloidal state of the order of 58% of the total mass of the additive.

In addition, the determination of the quantity of sulphonic acid contained by the additive (after separation of the constituents by dialysis then regeneration of the sulphonic acid by addition of hydrochloric acid; i.e. approximately 17.7% of the mass d 'additive) shows that only part of this acid is present in the additive, and that the ratio of the number of calcium atoms to the number of acid molecules contained is of the order of 17.4, or still that the ratio of the number of calcium atoms in the form of colloidal carbonate, the number of calcium atoms in the state of sulfonate, is of the order of 34.4, which constitutes a quite remarkable result.

The use of the methanol / isopropanol mixture also makes it possible to appreciably improve certain processes for the production of superbasic detergent additives for lubricants practiced in the prior art, as shown by the experiments described below.

EXAMPLE 13 (comparative)

In a constantly stirred 6 m ³ reactor, successively:

The temperature of the mixture is brought to 40 ° C. and then 177 kg of CO ₂ are admitted into the suspension over 3 hours.

• - phase liquide supérieure : essentiellement composée d'eau de réaction, d'alcool méthylique et de toluène mais aussi de traces de substances organiques solides, contenant du calcium, qui s'accumulent en fond de colonne de distillation lors de la récupération des solvants, ce qui constitue une gène opératoire importante.
• - phase liquide inférieure : essentiellement composée de toluène dans lequel est dissous l'additif détergent superbasique préparé.

The mixture is then left to stand for 1.5 hours; there is separation into two liquid phases:

• - upper liquid phase: mainly composed of reaction water, methyl alcohol and toluene but also traces of solid organic substances, containing calcium, which accumulate at the bottom of the distillation column during the recovery of the solvents, which is an important operative gene.
• - lower liquid phase: essentially composed of toluene in which the prepared superbasic detergent additive is dissolved.

ette solution is filtered, then directed to a fractionating column to remove the residual methyl alcohol and traces of water the reaction. This fraction rich in alcoholic compound is then mixed with the upper phase to the distillation column for the recovery of the alcohol.

the detergent additive thus obtained, after elimination of the toluene is: aractérisé by a calcium content of 12.9% by mass and by a TBN of 340 (ASTM D 664).

EXAMPLE 14

The same experiment as in Example 13 is carried out by replacing the 0.75 m ³ of methyl alcohol with 0.75 m ³ of a mixture consisting of:

After reaction, the mixture being left to stand for 1.5 hours; no demixing of liquid phases is observed.

The single liquid phase containing the additive is filtered and then directed, as before, to a distillation column for the recovery of the solvents.

The solvent-free additive is recovered liquid at the bottom of the column, the accumulation of solid organic products no longer occurring.

The superbasic detergent additive obtained under these improved operating conditions has characteristics very close to those of the additive obtained in the previous example, namely:

EXAMPLE 15

An additive prepared according to the operating protocol of Example 1 is used in a series of tests relating to the reduction of 1 ¹ "BOSCH" smoke index of a PEUGEOT INDENOR engine.

The additive is introduced into the diesel fuel at concentrations between 0.5 and 2 per 1000.

The smoke index is determined for each test according to the "BOSCH" method.

In the Table below, the results obtained are given with the diesel fuel not additivated, then additivated. The comparative results obtained from a commercial barium-based additive are also indicated.

EXAMPLE 16

An additive prepared according to the operating protocol of Example 1 is used in a series of tests relating to the reduction in the emission rate of unburned fuel from heavy fuel oil No. 2.

The additive is introduced into No. 2 heavy fuel oil (having a viscosity of 36.3 cSt at 100 ° C.) at 2 concentrations corresponding to 50 and 100 ppm by mass of calcium.

The same test is carried out, as for the previous example, with heavy fuel oil without additives (blank test).

During the experiments, the heavy fuel oil is sprayed mechanically under a pressure of 29 bars; the fuel supply rate is 90 kg / h. The air intake temperature is 25 ° C and the excess air is 25%.

The blackening weight index is determined for each test according to standard NF X 43-003. This is the gravimetric content of the solid particles corresponding to 1 thermal release (it is expressed in mg / th).

The table below gives the results obtained and also indicates the effectiveness of the additive, which corresponds to the relative reduction in the weight index (relative to the value of the blank test).

Claims (18)

1.- Process for the preparation of an organo-soluble calcium complex characterized in that it comprises: (a) reacting a sulfonic acid chosen from aliphatic, alicyclic and aromatic sulfonic acids with excess calcium oxide or hydroxide relative to the proportion corresponding to the stoichiometry of basic calcium sulfonate one mol of calcium oxide or hydroxide per gram equivalent of sulfonic acid, in a liquid medium comprising, (A) a solvent chosen from hydrocarbon or halo-hydrocarbon liquids, (B) methanol and (C) a C ₃ or C ₄ monoalcohol and in the presence of a minor proportion of at least one compound with nitrogen functions and with a long hydrocarbon chain; (b) bringing the reaction mixture resulting from step (a) into contact with an amount of carbon dioxide necessary to carbonate a substantial proportion of the excess calcium oxide or hydroxide; and (c) separation of the calcium complex formed, obtained in the organic phase. 2.- Method according to claim 1, characterized in that said C ₃ or C ₄ monoalcohol is isopropanol. where 2 / ₃ .- Method according to claim 1 / characterized in that the amounts of isopropanol and methanol are between them in a volume ratio of 1: 100 to 3.5: 1. 4.- Method according to one of claims 1 to 3 characterized in that the reaction medium further comprises a mineral oil of low viscosity, in a mass proportion relative to the sulfonic acid from 1: 5 to 2: 1. ₅ .- Method according to one of claims 1 to 4, characterized in that the solvent (A) is chosen from aromatic hydrocarbons, halogenated aliphatic hydrocarbons, gas oils and domestic fuel oils. _6. - Method according to one of claims 1 to 5, characterized in that said solvent (A) is used in a mass proportion of 1: 1 to 10: 1 relative.à sulfonic acid. 7.- Method according to one of claims 1 to 6 characterized in that the C3 or C4 monoalcohol and methanol are used in a total volume proportion of 8: 100 to 1: 1 relative to said solvent (A). 8.- Method according to one of claims 1 to 7, characterized in that said compound with nitrogen functions and long hydrocarbon chain is chosen from polyalkenylsuccinimide-amines of general formula

and bis (polyalkenylsuccinimide) -amines of general formula

where R represents a substantially saturated aliphatic hydrocarbon radical containing from 20 to 250 carbon atoms, X represents an alkylene radical of 2 to 5 carbon atoms, the two valences of which are located on separate carbon atoms and m takes a value from 1 to 5. _9. - Method according to one of claims 1 to 7, characterized in that said compound with nitrogen function and long hydrocarbon chain is chosen from amino acids corresponding to the general formula.

where R represents an alyphatic hydrocarbon radical containing from 6 to 22 carbon atoms, n takes an integer value from 0 to 4, and p, zero when n is zero, takes the value 0.1 or 2 when n is different from zero. 11 - Method according to one of claims 1 to 10, characterized in that said compound with nitrogen functions and long hydrocarbon chain is used in a proportion of 10 to 30% by mass relative to the sulfonic acid engaged. 12 - Method according to one of claims 1 to 11, characterized in that, in the first step, introducing calcium oxide or hydroxide in a proportion ranging from 1 to 30 gram atoms of metal, per equivalent -gram of sulfonic acid. 13 - Method according to one of claims 1 to 12, characterized in that the first step is carried out at a temperature of 20 to 65 ° C. ₁₄ - Method according to one of claims 1 to 13, characterized in that, in the second step, the reaction mixture resulting from the first step is brought into contact with carbon dioxide in highly divided form. 15 - Method according to one of claims 1 to 14, characterized in that the second step is carried out at a temperature of 20 to 65 ° C. 16 - Organo-soluble calcium complex obtained by a process according to claim 1. 17 - Organo-soluble calcium complex according to claim ¹⁶ , characterized in that it has a ratio of the number of gram atoms of calcium to the number of gram equivalent of sulfonic acid from 5: 1 to 20: 1 . 18 - A fuel or combustible composition comprising a gas oil or a fuel oil and a minor proportion of an organo-soluble calcium complex according to one of claims 16 and 17. 19 - Lubricating composition comprising a major proportion of lubricating oil and a minor proportion of an organo-soluble calcium complex according to one of claims 16 and 17.