EP1560901A1

EP1560901A1 - Improver containing fuel

Info

Publication number: EP1560901A1
Application number: EP03775289A
Authority: EP
Inventors: Peter Schwab; Stephan Hüffer; Mirjam Herrlich-Loos; Siegbert Brand
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2002-11-04
Filing date: 2003-11-03
Publication date: 2005-08-10
Also published as: AU2003283347A1; NO20052680L; DE10251312A1; US20060162238A1; NO20052680D0; KR20050084672A; WO2004041975A1; CA2504698A1; CN1711342A; JP2006505642A

Abstract

The invention relates to an improver in the form of a mixture of at least polysiloxane antifoaming agent and at least partially or totally neutralised fat acid. The inventive fuel and additive containing said mixture are also disclosed.

Description

Fuels with an improved additive effect Description

The present invention relates to an additive mixture containing at least one polysiloxane antifoam and at least one partially or completely neutralized fatty acid.

An important component of fuel additive packages are anti-foaming agents which are intended to dampen the natural foaming behavior of fuels, particularly when filling, for example during the refueling process at the petrol pump. Frequently used antifoams are polysiloxanes, in particular polysiloxane alkoxylates.

No. 6,093,222 describes anti-foam compositions for diesel fuels which comprise different polysiloxanes. The polysiloxanes are substituted with long-chain polyether groups, organic polyols, hydrocarbon residues and / or phenol residues. Due to the high costs for the production of the polysiloxane antifoam, however, these represent a not insignificant cost factor in the amount in which they are required to achieve an antifoam performance.

WO 95/04117 describes an additive composition which contains an anti-foam agent and a nitrogen-containing dispersant which burns ashes. The nitrogen-containing ash-free burning dispersant is said to increase the long-term storage stability of the anti-foam agent. However, the dispersant does not lower the amount of antifoam needed to dampen the foaming of a fuel.

The object of the present invention was to provide an additive mixture which has an improved anti-foam effect in comparison with anti-foam agents of the prior art.

The object was achieved by an additive mixture containing

i) as component A at least one polysiloxane antifoam and

ii) as component B at least one partially or completely neutralized fatty acid, a long-chain carboxylic acid, an ester of such a carboxylic acid or a mixture comprising at least one of these compounds. Suitable polysiloxane anti-foaming agents are all common anti-foaming agents based on polysiloxane known to the person skilled in the art. Such anti-foam agents are for example in the ATC Doσ. 52 describe "Fuel Additives and the Environment".

A preferred anti-foam agent is a polysiloxane of the general formula I

SiQ '4/2 (I)

wherein

the radicals R each independently represent a radical R ¹ , R ² , R ³ , R ⁴ or R ⁵ , in which

R ^{1 represents} an aromatic or saturated aliphatic hydrocarbon radical,

R ^{2 represents} an organic polyol,

R ^{3 represents} a polyether radical,

R ^{4 represents} a phenol radical, ^■ *

R ^{5 stands} for a radical R ² , but the hydroxyl groups are wholly or partly converted to diesters, diethers, acetals and / or ketals,

w = 2 + y + 2 z,

y and z each independently represent a number from 0 to 2, the sum of y and z corresponding to a number from 0 to 2 and

w + x + y + z = 20 to 60.

In R ¹ , the aromatic or saturated aliphatic hydrocarbon radical is preferably C 1 -C ₂₄ -alkyl, in particular methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, oσtyl, Deσyl, Dodeσyl or stearyl; C ₃ -C ₂ cycloalkyl, in particular others for cyσlopropyl, cyσlopentyl, cyσlohexyl, cyclooσtyl or cyσlodeσyl; C ₄ -C ₂ alkylσyσloalkyl, in particular for methylcyclohexyl, dimethylσyσlohexyl or ethylcyclohexyl; C _ö -Cio aryl, especially for phenyl; or C ₇ -C ₈ arylalkyl, in particular for methyl 5-phenyl, dimethylphenyl or phenylethyl. R ^{1 is} particularly preferably C ₁ -C ₂ -alkyl, in particular methyl.

In R ² , the organic polyol is preferably a saturated or unsaturated, branched or unbranched aliphatic

10 see hydrocarbon radical with at least two hydroxyl groups, which may be interrupted by one or more O atoms. The hydrocarbon residue is preferably saturated. The radical R ² preferably has a molecular weight of 100 to 700, particularly preferably 130 to 650 and in particular approximately

15 400, on.

The R ² radicals are introduced into the polysiloxane skeleton, for example, by reacting an unsaturated polyol with a polysiloxane which contains hydrogen atoms bonded to silicon. examples

20 games for polyols suitable for the production of saturated radicals R ² are trimethylolpropane monoallyl ether, ethoxylated pentaerythritol tolallyl ether, propoxylated pentaerythritol allyl ether, triisopropanolamine allyl ether, ethoxylated allyl sorbitol and 1,3-allyloxypropanediol. An example of a

25 saturated radical R ² suitable polyol is 2-butyn-1,4-diol.

R ³ preferably represents a polyether radical which contains at least 50% by weight, particularly preferably at least 75% by weight and in particular 100% by weight, of copolymerized ethylene oxide units. R ³ preferably has a molecular weight of up to 1,500, particularly preferably from 100 to 350.

R ⁴ preferably represents a phenol radical which is substituted by mono- or polyunsaturated alkene and / or alkyne radicals. Suitable examples are eugenol, vinylphenol, vinylguaiaσol and 4-allylphenol.

In preferred polysiloxanes of the formula I, the quotient of the number of R ⁱ groups and the number of R ² groups (R ¹ / R ² ) is 40 3 to 19.

In addition, in preferred polysiloxanes I the quotient of the sum of the number of R ³ , R ⁴ and R ⁵ groups and the number of R ² groups is [(R ³ + R ⁴ + R ⁵ ) / R ² ] 0 until 2. 45 In a preferred embodiment, component A contains a plurality of polysiloxanes I which are different from one another.

In a particularly preferred embodiment, a polysiloxane I as defined above is used with a polysiloxane of the general formula I .1

R * - SiQ '4/2 (1.1)

wherein

the radicals R * each independently represent a radical R ¹ or R ³ , where R ¹ and R ^{3 are} as defined for polysiloxane I;

a = 2 + σ + 2 d;

σ and d each independently represent a number from 0 to 2 and

a + b + c + d = 15 to 50,

and or

with a polysiloxane of the general formula 1.2

(1.2)

wherein

R, w, x, y and z are as defined for polysiloxane I, where R ^{2 is} a saturated polyol and

where the quotient of the number of R ³ groups and the number of R ² groups (R ³ / R ² ) and the quotient of the number of R groups and the number of R ² groups (R / R ² ) is greater than 0.

Such polysiloxane combinations are known, for example, from US Pat. No. 6,093,222, to which reference is hereby made in full.

In preferred polysiloxanes 1.1, the quotient of the number of R ¹ groups and the number of R ³ groups (RVR ³ ) is 3 to 19.

In preferred polysiloxanes 1.2, the quotient (R ³ / R ² ) is 0.25 to 5.

Component B is preferably a fatty acid partially or completely neutralized with amines.

Component B particularly preferably comprises at least one fatty acid salt of the formula II

[R-C00 ^Θ ] _{m + 1} (H)

wherein

R is C ₇ -C ₂₃ alkyl or mono- or polyunsaturated

C ₇ -C ₂₃ alkenyl, which is optionally substituted by one or more hydroxy groups;

A represents C ₂ -C ₈ alkylene;

Z represents Cx-Cs-alkylene, C ₃ -C ₈ -cycloalkylene or C ₆ -C ₁₂ -arylene or C ₇ -C ₂₀ -arylalkylene;

m represents a number from 0 to 5; and

x ¹ , x ² , x ³ and x ⁴ each independently represent a number from 0 to 24, at least one x not representing 0,

and optionally at least one further fatty acid RCOOH, where R is as defined above. Such fatty acid salts II are described, for example, in WO 01/38463, to which reference is hereby made in full.

The longer chain radical R occurring in the carboxylate anion RCOO or in the fatty acid RCOOH denotes, for example, branched or preferably linear C ₇ to C ₂₃ , preferably Cn to C ₂ , especially C ₅ to C, _alkyl groups , which can also carry hydroxyl groups. Examples of the underlying carboxylic acids are σtanoic acid, 2-ethylhexanoic acid, nonanoic acid, deσanoic acid, undeσanoic acid, dodeσanoic acid (lauric acid), tridecanoic acid, iso-tri-decanoic acid, tetradσanoic acid (myristic acid), hexadσanoic acid (palmitic acid) and oσtadanoic acid , The acids mentioned can be of natural or synthetic origin. Mixtures of the acids mentioned can also form the basis of the carboxylate anions.

However, the longer-chain radical R occurring in the carboxylate anion RCOO or in the fatty acid RCOOH preferably denotes mono- or polyunsaturated C ₇ to C ₂₃ radicals, in particular mono- or polyunsaturated Cn to C ₂ ι-, especially C ₁₅ to C ₁₉ alkenyl groups, which can additionally carry hydroxyl groups. These unsaturated residues are preferably linear. Monounsaturated fatty acids are, for example, palmitoleic, oleic and eruic acid. In the case of polyunsaturated alkenyl groups, these preferably contain two or three double bonds. Examples of the underlying carboxylic acids are elaidic acid, ricinoleic acid, linoleic acid and linolenic acid. Particularly good results are achieved with oleic acid. Mixtures of such unsaturated carboxylic acids with one another and also with the above-mentioned saturated carboxylic acids can also form the basis of the carboxylate anions. Such mixtures are, for example, tall oil, tall oil fatty acid and rapeseed oil fatty acid. The unsaturated carboxylic acids and the mixtures mentioned are generally of natural origin.

The alkylene group A in compounds of the formula II is preferably derived from corresponding alkylene oxides such as ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide and ice or trans-2,3-butylene oxide. However, it can also represent 1,3-propylene, 1,4-butylene, 1,6-hexylene or 1,8-octylene. A can also represent a mixture of different of the groupings mentioned. For A, ethylene, 1,2-propylene or 1,2-butylene groups are particularly preferred.

The variable Z means in particular C _x - to C ₄ -alkylene groupings such as methylene, 1,2-propylene, 1,2-butylene, 1,3-butylene or 2,3-butylene, C ₅ - to C _β -cycloalkylene groupings like 1,3-cyclo- pentylidene or 1,3- or 1,4-cyclohexylidene or C ₆ - to C ₈ -arylene or -arylalkylene groups such as 1,3- or 1,4-phenylene, 2-methyl-l, 4-phenylene or 1 , 3- or 1,4-bismethylene phenylene.

However, the variable Z preferably means polymethylene groupings of the formula - (CH ₂ ) _n - with n = 2 to 8, in particular with n = 2 to 6, that is to say in particular 1,2-ethylene, 1,3-propylene, 1,4 -Butylene, 1,5-pentylene and 1,6-hexylene, but also 1,7-heptylene and 1,8-oσtylene.

If the variable m stands for 0, as a rule, depending on the sum (Σ) of all variables x ¹ , x ² and x ³ , mixtures of mono-, di- and / or trialkanolamines or pure trialkanolamines are the cationic fatty acids used according to the invention Component. Examples of such alkanolamines are monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine and the associated mixtures. In this group, the oleic acid salt of triethanolamine is [(x ¹ + x ² + x ³ ) = 3; A = ethylene] of particular interest.

However, the variable m preferably stands for the number 1 or 2. For = 1, completely and / or partially alkoxylated alkylenediamines such as 1,2-ethylenediamine, 1,3-propylenediamine or 1,4-butylenediamine are used. For m = 2 there are usually completely and / or partially alkoxylated dialkylenetriamines such as di- (1,2-ethylene) -triamine, di- (1,3-propylene) -triamine or di- (1,4-butylene) -triamine , In this group are the bis-oleic acid salts of N, N, N ', N'-tetrakis (2' -hydroxyethyl) -l, 2-ethylenediamine (∑x = 4) and N, N, N ', N '-Tetrakis- (2'-hydroxypropyl) -l, 2-ethylenediamine (∑x = 4) and the tris-oleic acid salts of di- (1,2- ethylene) triamine of particular interest.

However, it is also possible to use higher homologs of the alkylene diamines and dialkylene triamines mentioned, such as, for example, triethylene tetramine (m = 3), tetraethylene penta in (m = 4) or pentaethylene hexamine (m = 5), as the amine component for the fatty acid salts used according to the invention ,

In a preferred embodiment, the number x, ie the sum of x ¹ , x ² , x ³ and x ⁴ (∑x), of the alkylene oxide units (OA) introduced per amine molecule is based on the number of NH bonds in the base Amine dependent and can correspond to the number of NH bonds (∑x = m + 3). However, more or fewer OA units can also be installed. In the case of overstoσhiometrisσhem incorporation is a Dreifaσhalkoxylierung per NH bond [300% of (m + 3)] in view of the properties of the resulting fat acid salts are a preferred upper limit. In the case of sub-stoichiometric incorporation, an average 50% alkoxylation [50% of (m + 3)] is a corresponding preferred lower limit; here mostly mixtures of species with different degrees of alkoxylation are present.

In a particularly preferred embodiment, the sum (Σ) of all variables x has a value of 75% to 125% of (m + 3).

The fatty acid salts of the general formula II can usually be prepared easily by alkoxylation of the underlying amines using conventional methods and subsequent neutralization with the fatty acids of the formula RCOOH.

If C ₂ -C ₄ -alkylene oxides are used, the alkoxylation is used for the introduction of the first alkylene oxide unit into the NH bond in the presence of small amounts of water (usually 0.5 to 5% by weight, based on the amount of amine used) without catalyst at temperatures from 80 to 140 ° C and for the introduction of further alkylene oxide units with the exclusion of water in the presence of basic catalysts such as alkali metal hydroxides, eg. As sodium or potassium hydroxide, carried out at temperatures from 100 to 150 ° C.

The neutralization is generally carried out by heating the alkoxylated amine thus obtained with the corresponding stoichiometric amount or by providing the stoichiometric amount (ie 90 to 100%, in particular 95 to 100% of theory) of fatty acid to temperatures of 30 to 100 ° C., in particular 40 to 80 ° C, for a period of 15 minutes to 10 hours, in particular 30 minutes to 5 hours. The neutralization reaction should be carried out so that no carboxylic ester components are formed in the product. In many cases, both the alkoxylated amine and the fatty acid can be used as liquids, which makes the conversion to the corresponding fatty acid salt particularly easy. The order of combining alkoxylated amine and fatty acid is not critical, i.e. one can both add the alkoxylated amine and add the fatty acid and also add the fatty acid and add the alkoxylated amine.

In principle, however, it is also possible to add the alkoxylated amine and the fatty acid as individual components to the additive concentrates or mineral oil products and to allow the salt formation to take place there.

Long-chain carboxylic acids, esters thereof or are also suitable as brewable components B for the additive mixture according to the invention Brewable mixture which contain at least one of these components.

Long-chain carboxylic acids in the sense of the present invention include saturated and unsaturated mono- or polycarboxylic acids with 4 to 50 carbon atoms, preferably 8 to 24 carbon atoms. If the carboxylic acids are in dimerized form, the number of carbon atoms is doubled accordingly. Polycarboxylic acids according to the invention preferably comprise 2 to 4 carboxyl groups. Unsaturated carboxylic acids according to the invention comprise one or more, preferably one, two or three, in particular not cumulative, double bonds.

The preferred examples of saturated or unsaturated long-chain monoarboxylic acids are the saturated or unsaturated C ₈ -C ₄ -monoarboxylic acids given in connection with the above definition for the compound of the formula II.

Examples of suitable polycarboxylic acids are saturated or unsaturated diarboxylic acids, such as the dimerized variant of oleic acid.

The carboxylic acids used can be of natural or synthetic origin. They can be used as a pure substance or as a mixture of substances which contains one or more of these carboxylic acids, optionally together with other substances. Tall oil fatty acid solutions can be mentioned as no limiting examples. These typically include a mixture of saturated, monounsaturated and polyunsaturated C ₈ carboxylic acids and alternating portions of a saponifiable resin. Suitable products are described, for example, in WO-A-98/04656, to which express reference is hereby made.

The usable long-chain carboxylic acid esters according to the invention can be obtained in a conventional manner by reacting the above long-chain carboxylic acids with mono- or polyhydric alcohols.

The alcohols contained in the esters according to the invention are preferably derived from straight-chain or branched Ci to C ₂ o -alkanes and carry 1 to 8, such as 1 to 4, hydroxyl groups. Cyclic alcohols with 6 to 12 carbon atoms are also brewable.

Preferred niσhtσyσlisσhe alcohols or polyhydric alcohols comprise 2 to 12, such as 2 to 5, carbon atoms, are straight-chain or branched and have 1 to 4 hydroxyl groups. As Not limiting examples include monohydric alcohols such as methanol, ethanol, n- and iso-propanol and polyhydric alcohols such as glycol, glycerin, trimethylolpropane, pentaerytritol, sorbitol, mannitol, inositol, glucose and fructose. The hydrocarbyl residue of the alcohols which can be used according to the invention can optionally contain one or more heteroatoms, such as oxygen, sulfur, nitrogen or phosphorus, in the carbon chain.

When polyhydric alcohols are used, these can be present in the esters according to the invention in partially or completely esterified form. Mono and diester esters are preferred.

As non-limiting examples of brewable esters, methyl esters of the above saturated or unsaturated monoarboxylic acids are to be mentioned, as well as the corresponding esterification products of naturally occurring fatty acids or fatty acid mixtures. In particular, monoesters or diesters such as, for example, glycerol monooleate, glycerol dioleate and glycerol monostearate can be mentioned.

In the additive mixture according to the invention, component A and component B are used in a weight ratio of preferably 1: 200 to 1:10, particularly preferably 1: 100 to 1:10 and in particular 1:50 to 1:10.

Another object of the present invention is the use of the additive mixture according to the invention for the additivation of fuel compositions, in particular for improving the anti-foam performance of a fuel composition.

Suitable fuels are petrol and middle distillates, such as diesel fuels, heating oil or kerosene, with diesel fuels being preferred.

The diesel fuels are, for example, petroleum refines, which usually have a boiling range of 100 to 400 ° C. These are mostly distillates with a 95% point up to 360 ° C or beyond. However, these can also be so-called "Ultra Low Sulfur Diesel" or "City Diesel", characterized by a 95% point of, for example, a maximum of 345 ° C and a sulfur content of a maximum of 0.005% by weight or a 95% point of, for example, 285 ° C. and a maximum sulfur content of 0.001% by weight. In addition to the diesel fuels available through refining, those available through coal gasification or gas liquefaction ("gas to liquid (GTL) fuels) are also suitable. Mixtures of the above-mentioned called diesel fuels with renewable fuels, such as biodiesel.

The additive mixture according to the invention is particularly preferred for additizing diesel fuels with a low sulfur content, ie. H. with a sulfur content of less than 0.05% by weight, preferably less than 0.02% by weight, in particular less than 0.005% by weight and especially less than 0.001% by weight of sulfur.

The present invention also relates to a fuel composition comprising a main amount of a hydrocarbon fuel and an effective amount of the additive mixture according to the invention and optionally at least one further additive. With regard to suitable fuels, the above applies.

The additive mixture according to the invention is preferably present in the fuel in an amount of 1 to 1000 ppm by weight, particularly preferably 20 to 300 ppm by weight and in particular 50 to 150 ppm by weight, based on the total amount of the additive fuel.

Another object of the present invention is an additive concentrate containing the additive mixture according to the invention, at least one diluent and optionally at least one further additive.

Suitable diluents are, for example, fractions obtained in petroleum processing, such as kerosene, naphtha or Brightstoσk. Aromatic and aliphatic hydrocarbons and alkoxyalkanols are also suitable. In the case of middle distillates, particularly preferred diluents for diesel fuels, naphtha, kerosene, diesel fuels, aromatic hydrocarbons, such as solvent naphtha sσhwer, solvent or shell sol, and mixtures of these solvents and diluents.

The additive mixture according to the invention is in the concentrate in a concentration of 0.1 to 80% by weight, particularly preferably 0.1 to 60% by weight and in particular 15 to 50% by weight, based on the total weight of the concentrate , in front.

Suitable additives which can be contained in the fuel or concentrate according to the invention in addition to the additive mixtures according to the invention, in particular for diesel fuels, include detergents, corrosion inhibitors, dehazers, demulsifiers, other customary foam inhibitors ("antifoam"), antioxidants, metal detergents. activators, multifunctional stabilizers, cetane number improvers, combustion improvers, dyes, markers, solubilizers, antistatics, lubricity improvers, the cold-affecting additives, such as flow improvers ("MDFI"), paraffin dispersants ("WASA") and the combination of the last two additives ( "WAFIs"). Suitable additives are described, for example, in Ulimann's Encyclopedia of Industrial Chemistry (1990) Vol. A 16, pp. 719 ff., To which reference is expressly made here.

The usual foam inhibitors include the polysiloxanes mentioned at the outset, alylated polyamines and their mixtures with various N-asylum compounds, such as polyalkenylsuccinic acid amides.

The synergistically effective combination of components A and B in the additive mixture according to the invention leads to a significant improvement in the anti-foam performance of fuels additized with it in comparison with additives of the prior art.

The following examples are intended to illustrate the invention without, however, restricting it.

Examples The tests described below were carried out with the following fuels:

- Diesel fuel according to DIN EN 590 with a sulfur content of 48 ppm: Diesel I

- Diesel fuel according to DIN EN 590 with a sulfur content of 15 ppm (ULSD): Diesel II

- Diesel fuel according to DIN EN 590 with a sulfur content of 4 ppm (MK1): Diesel III

- Blend from 5% biodiesel in 95% Diesel I: Blend I

- Blend from 8% ethanol in 91% Diesel I (1% stabilizer package): Blend II

- Gas to liquid fuel: GTL

- Blend from 20% GTL in 80% Diesel I: Blend III

The following products were used as lubricity improvers:

Lubriσity I: Product manufactured according to Example 1

Lubriσity II: Tall oil fatty acid mixture obtainable under the trade name Keroσom LA 99 from BASF AG Lubriσity III: fatty acid ester mixture with glycerin monooleate as the main component.

A commercially available polysiloxane derivative with the designation anti-foam was used as an anti-foaming agent.

Example 1: Synthesis of a lubricity improver (Lubri- city I)

58.4 g (0.2 mol) of N, N, N ', N'-tetrakis (2'-hydroxypropyl) -l, 2-ethylenediamine (obtained from 1,2-ethylenediamine and 4 mol of propylene oxide in the presence of 3% by weight of water, based on the amount of the amine used), the mixture was heated to 60-80 ° C. and 110.4 (0.4 mol) of oleic acid were added with stirring within two hours. The pH did not drop below 7. Finally, the mixture was stirred for two hours. The product obtained had an N titer of 2.39 mmol / g.

Example 2: Try to determine the anti-foam performance

The determination of the anti-foam performance was carried out according to the BNPe test according to standard NF M 07-075.

The additive fuels or blends were added by adding the above. Combinations of 5 mg / kg antifoam and 120 mg / kg lubricity improvers Lubricity I to III are obtained. The table below shows the values determined for the foam volume and the foam degradation time in dry fuels.

The lubricity improver alone had no positive influence on the foam effect.

The combinations of antifoam and lubricity I, II and III according to the invention showed, in comparison with the effect of antifoam alone, a significantly improved antifoam performance, with the same effect on improving the lubricity. Particularly excellent results are achieved when using lubrication improvers of the Lubriσity I type.

Claims

Patentansprüσhe

Additive mixture containing

i) as component A at least one polysiloxane anti-foaming agent and

ii) as component B at least one partially or completely neutralized fatty acid, a long-chain carboxylic acid, an ester of such a carboxylic acid or a mixture comprising at least one of these compounds.

Additive mixture according to claim 1, component A comprising at least one polysiloxane of the general formula I,

(I)

wherein the radicals R each independently of one another for a radical R ¹ ,

R ² , R ³ , R ⁴ or R ⁵ stand in which

R ¹ for an aromatic or saturated aliphatic

Hydrocarbon radical, R ^{2 stands} for an organic polyol, R ^{3 stands} for a polyether radical, R ^{4 stands} for a phenol radical, R ^{5 stands} for a radical R ² , but the hydroxyl groups wholly or partly to diesters, diethers, acetals and / or Ketals are implemented, w = 2 + y + 2 z, y and z each independently represent a number from 0 to 2, the sum of y and z corresponding to a number from 0 to 2 and w + x + y + z = 20 to 60.

3. Additive mixture according to claim 2, whereby in component A

R ^{1 represents} C ₁ -C ₂₄ -alkyl, C ₃ -C ₂₄ -cycloalkyl, C ₄ -C ₂₄ -alkylσyσloalkyl, C _δ -cio-ryl or C ₇ -C ₈ -arylalkyl

R ^{2 represents} a saturated or unsaturated, branched or unbranched aliphatic hydrocarbon radical which is substituted by at least two hydroxyl groups and is optionally interrupted by one or more O atoms,

R ^{3 stands} for a polyether radical which contains at least 50% by weight of ethylene oxide units in copolymerized form and has a molecular weight of up to 1,500,

the quotient of the number of R ¹ groups and the number of R ² groups (RVR ² ) is 3 to 19 and

the quotient of the sum of the number of R ³ , R ⁴ and R ⁵ groups and the number of R ² groups [(R ³ + R + R ⁵ ) / R ² ] is 0 to 2.

4. Additive mixture according to one of the preceding claims, wherein component B comprises at least one fatty acid neutralized with at least one amine.

5. Additive mixture according to claim 4, component B comprising at least one fatty acid salt of the formula II

wherein

R represents C ₇ -C ₂₃ alkyl or mono- or polyunsaturated CC ₂₃ alkenyl, which are optionally substituted by one or more hydroxyl groups;

A represents C ₂ -C ₈ alkylene;

Z represents CC ₈ alkylene, C ₃ -C ₈ cyloalkylene or C ₆ -C ₂ arylene or C ₇ -C ₂₀ arylalkylene; m represents a number from 0 to 5; and

x ¹ , x ² , x ³ and x ⁴ each independently represent a number from 0 to 24,

and optionally at least one further fatty acid RCOOH, wherein R is as defined above.

6. Additive mixture according to one of claims 1 to 3, component B comprising at least one saturated or unsaturated mono- or polycarboxylic acid with 4 to 50 carbon atoms or at least one ester of such a carboxylic acid with a mono- or polyhydric alcohol with 1 to 20 carbon atoms and 1 to 8 hydroxyl groups.

7. Additive mixture according to one of the preceding claims, component A and component B being present in a weight ratio of 1: 200 to 1:10.

8. Use of the additive mixture, as defined in one of the preceding claims, for the additization of fuel compositions.

9. Use according to claim 8, to improve the anti-foam performance of a fuel composition.

10. A fuel composition containing a main amount of a hydrocarbon fuel and an effective amount of an additive mixture defined as in one of claims 1 to 7 and optionally at least one further additive.

11. Fuel composition according to claim 10 or use according to claim 8 or 9, where the fuel is diesel fuel, heating oil or kerosene.

12. Fuel composition or use according to claim 11, whereby the diesel fuel is a sol that is obtained by refining, coal gasification or gas liquefaction, or a mixture thereof with regenerative fuels.

13. Additive concentrate containing an additive mixture as defined in one of claims 1 to 7 and at least one diluent and, if appropriate, at least one further additive.