Quaternised nitrogen compounds and their use as additives in fuels and lubricants

Abstract

The invention relates to novel quaternized nitrogen compounds, to the production thereof, and to the use thereof as fuel additives and lubricant additives, such as in particular detergent additives, additive packages that contain said compounds, and fuels and lubricants to which said additive packages have been added. The invention further relates to the use of said quaternized nitrogen compounds as a fuel addition for reducing or preventing deposits in the injection systems of direct-injection diesel engines, in particular in common-rail injection systems, for reducing the fuel consumption of direct-injection diesel engines, in particular diesel engines having common-rail injection systems, and for minimizing the power loss in direct-injection diesel engines, in particular in diesel engines having common-rail injection systems.

Description

[0001] The present invention relates to novel fuel compositions containing a reaction product comprising a quaternized nitrogen compound. The reaction products of the present invention are suitable for use as a fuel additive for reducing or preventing deposits in the injection systems of direct-injection diesel engines, particularly in common-rail injection systems, for reducing fuel consumption in direct-injection diesel engines, particularly in diesel engines with common-rail injection systems, and for minimizing power loss in direct-injection diesel engines, particularly in diesel engines with common-rail injection systems. State of the art:

[0002] In direct-injection diesel engines, the fuel is injected through a multi-hole injection nozzle extending directly into the engine's combustion chamber and dispersed (atomized) as finely as possible, rather than being introduced into a pre-chamber or swirl chamber as in a conventional (chamber) diesel engine. The advantage of direct-injection diesel engines is their high performance for a diesel engine while maintaining low fuel consumption. These engines also achieve very high torque even at low engine speeds.

[0003] There are currently three main methods used to inject fuel directly into the combustion chamber of the diesel engine: the conventional distributor injection pump, the pump-nozzle system (unit injector system or unit pump system) and the common rail system.

[0004] In the common rail system, diesel fuel is pumped into a high-pressure line, the common rail, by a pump at pressures of up to 2000 bar. Branch lines from the common rail lead to the various injectors, which inject the fuel directly into the combustion chamber. The common rail is always at full pressure, enabling multiple injection or a special injection pattern. In contrast, other injection systems allow only a limited variation in injection timing. Common rail injection is essentially divided into three groups: (1) pre-injection, which essentially achieves smoother combustion, reducing harsh combustion noise ("knocking") and making the engine run smoothly; (2) main injection, which is primarily responsible for a good torque curve; and (3) post-injection, which particularly ensures low NOx levels.During this post-injection, the fuel is generally not burned but vaporized by residual heat in the cylinder. The resulting exhaust gas / fuel mixture is transported to the exhaust system, where the fuel, in the presence of suitable catalysts, acts as a reducing agent for nitrogen oxides (NOx).

[0005] The variable, cylinder-specific injection of the common-rail injection system can positively influence the engine's pollutant emissions, such as nitrogen oxides (NO x ), carbon monoxide (CO), and especially particulates (soot). This allows, for example, engines equipped with common-rail injection systems to theoretically meet the Euro 4 standard without the need for an additional particulate filter.

[0006] In modern common-rail diesel engines, under certain conditions, for example, when using fuels containing biodiesel or fuels with metal impurities such as zinc compounds, copper compounds, lead compounds, and other metal compounds, deposits can form at the injector openings. These deposits negatively impact the fuel injection behavior and thus impair engine performance, particularly reducing power, but also sometimes worsening combustion. The formation of deposits is further exacerbated by further developments in the design of the injectors, particularly by changes to the geometry of the nozzles (narrower, conical openings with a rounded outlet). For the long-term optimal functioning of the engine and injectors, such deposits in the nozzle openings must be prevented or reduced using suitable fuel additives.

[0007] Deposits in the injection systems of modern diesel engines cause significant performance problems. It is widely recognized that such deposits in the spray channels can lead to reduced fuel flow and thus to power loss. Deposits at the injector tip, on the other hand, impair the optimal formation of fuel spray, resulting in impaired combustion and, consequently, higher emissions and increased fuel consumption. In contrast to these conventional, "external" deposit phenomena, "internal" deposits (collectively referred to as internal diesel injector deposits (IDID)) in certain parts of the injectors, such as the nozzle needle, control piston, valve piston, valve seat, control unit, and the guides of these components, are also increasingly causing performance problems. Conventional additives are ineffective against these IDIDs.

[0008] US Pat. No. 4,248,719 describes quaternized ammonium salts produced by reacting an alkenyl succinimide with a monocarboxylic acid ester. These salts are used as dispersants in lubricating oils to prevent sludge formation. In particular, the reaction of polyisobutylsuccinic anhydride (PIBSA) with N,N-dimethylaminopropylamine (DMAPA) and quaternization with methyl salicylate is described. However, it does not suggest any use in fuels, particularly diesel fuels. The use of PIBSA with low degrees of bismaleation (<20%) is not described.

[0009] US Pat. No. 4,171,959 describes quaternized ammonium salts of hydrocarbyl-substituted succinimides, which are suitable as detergent additives for gasoline compositions. Alkyl halides are preferably used for quaternization. Organic C 2 -C 8 hydrocarbyl carboxylates and sulfonates are also mentioned. Consequently, the quaternized ammonium salts provided according to the teaching therein have either a halide or a C 2 -C 8 hydrocarbyl carboxylate or a C 2 -C 8 hydrocarbyl sulfonate group as the counterion. The use of PIBSA with low degrees of bismaleation <20% is also not described therein.

[0010] EP-A-2 033 945 discloses cold flow improvers produced by quaternizing specific tertiary monoamines bearing at least one C 8 -C 40 alkyl radical with a C 1 -C 4 alkyl ester of specific carboxylic acids. Examples of such carboxylic acid esters are dimethyl oxalate, dimethyl maleate, dimethyl phthalate, and dimethyl fumarate. Applications other than improving the CFPP value of middle distillates are not documented in EP-A-2 033 945.

[0011] WO 2006 / 135881 describes quaternized ammonium salts prepared by condensing a hydrocarbyl-substituted acylating agent with an oxygen- or nitrogen-containing compound with a tertiary amino group, followed by quaternization using hydrocarbyl epoxide in combination with stoichiometric amounts of an acid, such as acetic acid. Other quaternizing agents claimed in WO 2006 / 135881 are dialkyl sulfates, benzyl halides, and hydrocarbyl-substituted carbonates, with dimethyl sulfate, benzyl chloride, and dimethyl carbonate being experimentally investigated.

[0012] However, the quaternizing agents preferably used in WO 2006 / 135881 have serious disadvantages, such as: toxicity or carcinogenicity (e.g. in the case of dimethyl sulfate and alkylene oxides and benzyl halides), no residue-free combustion (e.g. in the case of dimethyl sulfate and alkyl halides), and insufficient reactivity, which leads to incomplete quaternization or uneconomical reaction conditions (long reaction times, high reaction temperatures, excess of quaternizing agent; e.g. in the case of dimethyl carbonate).

[0013] WO 2011 / 141731 A1 describes a gasoline composition containing a quaternary ammonium salt as an additive. This additive is prepared by reacting a carboxylic acid ester with a reaction product obtainable by reacting a hydrocarbyl-substituted acylating agent with a compound containing an oxygen or nitrogen group and a quaternizable ammonium group. The additive is used to reduce deposits in intake valves or injection nozzles of a gasoline engine.

[0014] WO 2011 / 095819 A1 describes a diesel fuel composition containing a quaternary ammonium salt as an additive. The additive is used to minimize power loss in direct-injection diesel engines or to reduce deposits in injection nozzles in direct-injection diesel engines. The additive is prepared by reacting a carboxylic acid ester with a reaction product obtainable by reacting a hydrocarbyl-substituted acylating agent with a compound containing an oxygen or nitrogen group and a quaternizable ammonium group.

[0015] The object was therefore to provide improved quaternized fuel additives, in particular based on hydrocarbyl-substituted polycarboxylic acid compounds, which no longer have the disadvantages of the prior art. Brief description of the invention:

[0016] It has now surprisingly been found that the above object is achieved by providing special quaternized nitrogen compounds or fuel compositions additives therewith.

[0017] Surprisingly, the additives produced in this way are superior to the additives produced conventionally according to the state of the art in several respects: They have low toxicity (due to the targeted choice of the quaternizing agent), burn ashless, have a high content of quaternized product, and allow an economical reaction during their production. And surprisingly, they have improved handling properties, such as in particular improved solubility, particularly in diesel performance additive packages. At the same time, the additives described here show an improved effect with regard to the prevention of deposits in diesel engines, as particularly illustrated by the enclosed application examples. Detailed description of the invention: A1) Special embodiments

[0018] The present invention relates to the fuel compositions defined in the claims. In particular, the present invention relates to the following specific embodiments: 1. A fuel composition containing, in a major amount of a conventional fuel, a proportion (in particular an effective amount) of at least one reaction product comprising a quaternized nitrogen compound, wherein the reaction product is obtainable by a1) reacting a polycarboxylic acid compound substituted with high molecular weight hydrocarbyl, with a compound comprising at least one oxygen or nitrogen group reactive with the polycarboxylic acid, in particular addable or condensable, and containing at least one quaternizable amino group, thereby obtaining a quaternizable hydrocarbyl-substituted polycarboxylic acid compound (by addition or condensation), and a2) subsequently reacting the compound with a quaternizing agent containing the at least one quaternizable, such astertiary amino group into a quaternary ammonium group, wherein the quaternizing agent is the alkyl ester of a cycloaromatic or cycloaliphatic mono- or polycarboxylic acid (in particular a mono- or dicarboxylic acid) or an aliphatic polycarboxylic acid (in particular dicarboxylic acid); or b) reacting a quaternizable polycarboxylic acid compound substituted with high molecular weight hydrocarbyl, containing at least one quaternizable amino group with a quaternizing agent which contains the at least one quaternizable, such astertiary amino group is converted into a quaternary ammonium group, wherein the quaternizing agent is the alkyl ester of a cycloaromatic or cycloaliphatic mono- or polycarboxylic acid (in particular a mono- or dicarboxylic acid) or an aliphatic polycarboxylic acid (in particular dicarboxylic acid), wherein 1.25 to 2.0 equivalents of quaternizing agent are used per equivalent of quaternizable tertiary nitrogen atom. 2. The fuel composition according to embodiment 1, wherein 1.25 to 2.0 equivalents, such as 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or 1.9 equivalents, of quaternizing agent are used per equivalent of quaternizable tertiary nitrogen atom. Significantly improved product yields can be achieved by increasing the proportion of quaternizing agent within the claimed range. 3.A fuel composition according to any one of the preceding embodiments, wherein the hydrocarbyl-substituted polycarboxylic acid compound is a polyisobutenylsuccinic acid or an anhydride thereof, having a bismaleation level of 2 to 20% or 2 to 15%, such as 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, or 2%, based in each case on the reaction product. Lower bismaleation levels can contribute to a significant improvement in the solubility of the additive and / or compatibility of the components when formulating additive packages. 4.Fuel composition according to one of the preceding embodiments, wherein the quaternizing agent is a compound of the general formula 1 R 1 OC(O)R 2 (1) wherein R 1 represents a low molecular weight hydrocarbyl radical, such as an alkyl or alkenyl radical, in particular a lower alkyl radical, such as methyl or ethyl, and R 2 represents an optionally substituted mononuclear cyclic hydrocarbyl radical, in particular an aryl or cycloalkyl or cycloalkenyl radical, in particular aryl, such as phenyl, wherein the substituent is selected from OH, NH 2 , NO 2 , C(O)OR 3 , and R 1 OC(O)-, wherein R 1 has the meanings given above and R 3 represents H or R 1 , wherein the substituent is in particular OH. In particular, the quaternizing agent is a phthalate or a salicylate, such as dimethyl phthalate or methyl salicylate. 5.Fuel composition according to one of the preceding embodiments, wherein the quaternizing agent is a compound of the general formula 2 R 1 OC(O)-AC(O)OR 1a (2) wherein R 1 and R 1a independently of one another represent a low molecular weight hydrocarbyl radical, such as an alkyl or alkenyl radical, in particular a lower alkyl radical, and A represents hydrocarbylene (such as in particular C 1 -C 7 alkylene or C 2 -C 7 alkenylene). 6. Fuel composition according to one of the preceding embodiments, wherein the quaternized nitrogen compound has a number-average molecular weight in the range from 400 to 5000, in particular 800 to 3000 or 900 to 1500. 7.Fuel composition according to one of the preceding embodiments, wherein the quaternizing agent is selected from alkyl salicylates, dialkyl phthalates, and dialkyl oxalates; alkyl salicylates, in particular lower alkyl salicylates, such as methyl, ethyl, and n-propyl salicylates, are particularly preferred. 8.Fuel composition according to embodiment 1, wherein the compound reactive with the polycarboxylic acid (addable or condensable) containing an oxygen or nitrogen group and at least one quaternizable amino group is selected from a) hydroxyalkyl-substituted mono- or polyamines having at least one quaternizable, primary, secondary, or tertiary amino group; b) straight-chain or branched, cyclic, heterocyclic, aromatic, or non-aromatic polyamines having at least one primary or secondary amino group and having at least one quaternizable, primary, secondary, or tertiary amino group; c) piperazines, with group a. being particularly mentioned.Fuel composition according to embodiment 8, wherein the compound reactive with the polycarboxylic acid, in particular addable or condensable, containing an oxygen or nitrogen group and at least one quaternizable amino group is selected from a) hydroxyalkyl-substituted primary, secondary, or tertiary monoamines and hydroxyalkyl-substituted primary, secondary, or tertiary diamines; b) straight-chain or branched aliphatic diamines having two primary amino groups; di- or polyamines having at least one primary and at least one secondary amino group; di- or polyamines having at least one primary and at least one tertiary amino group; aromatic carbocyclic diamines having two primary amino groups; aromatic heterocyclic polyamines having two primary amino groups; aromatic or non-aromatic heterocycles having one primary and one tertiary amino group; where group a. is particularly noteworthy.10. A fuel composition according to any one of the preceding embodiments, selected from diesel fuels, biodiesel fuels, gasoline fuels, and alkanol-containing gasoline fuels. 11. A fuel composition according to any one of the preceding embodiments, wherein the hydrocarbyl-substituted polycarboxylic acid compound is a polyisobutenylsuccinic acid or anhydride (PIBSA) thereof, which has a low degree of bismaleination, in particular 10% or less than 10%, such as 2 to 9%, or 3 to 7%. In particular, such PIBSAs are derived from HR-PIB with a Mn in the range of about 400 to 3000. In particular, the above fuel compositions are primarily diesel fuels. The following uses are not subject of the invention. 12.Use of a reaction product obtainable by a process as defined in one of the preceding embodiments, in particular according to embodiment 2, 3, 4, 5 and especially embodiment 7, 8 or 9, or of a quaternized nitrogen compound obtained from the reaction product by partial or complete purification, as a fuel additive. In a particular embodiment (A), quaternized reaction products are provided which are prepared starting from polyisobutenylsuccinic acid or an anhydride thereof, said compound having a degree of bismaleation of 2 to 20% or 2 to 15%, such as 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3 or 2%.This polyisobutenylsuccinic acid compound is reacted (by addition or condensation) with a compound comprising at least one oxygen or nitrogen group reactive with the polyisobutenylsuccinic acid compound (in particular, addable or condensable) and containing at least one quaternizable amino group, and then quaternized. In a particular embodiment (B), quaternized reaction products are provided, which are obtained by quaternization using an excess of quaternizing agent. In particular, about 1.1 to about 2.0 or about 1.25 to about 2.0 equivalents, such as 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or 1.9 equivalents, of quaternizing agent are used per equivalent of quaternizable tertiary nitrogen atom.Particularly useful quaternizing agents are those of formula (1), in particular the lower alkyl esters of salicylic acid, such as methyl salicylate, ethyl salicylate, n- and i-propyl salicylate, and n-, i-, or tert-butyl salicylate. In a further particular embodiment (C), embodiments (A) and (B) are combined, i.e., the quaternizable compounds prepared from the above polyisobutenylsuccinic acid compounds according to embodiment (A) are quaternized according to embodiment (B). 13.Use of a quaternized nitrogen compound according to embodiment 12, prepared by a process comprising reacting a quaternizable hydrocarbyl-substituted polycarboxylic acid compound containing at least one tertiary, quaternizable amino group with a quaternizing agent that converts the at least one tertiary amino group into a quaternary ammonium group, wherein the quaternizing agent is the alkyl ester of a cycloaromatic or cycloaliphatic mono- or polycarboxylic acid (in particular a mono- or dicarboxylic acid) or an aliphatic polycarboxylic acid (in particular dicarboxylic acid), and wherein about 1.1 to about 2.0 or about 1.25 to about 2.0 equivalents of quaternizing agent are used per equivalent of quaternizable tertiary nitrogen atom, as a fuel additive. 14.Use of a reaction product or a quaternized nitrogen compound according to embodiment 12 or of a compound prepared according to embodiment 13 as a fuel additive, in particular a diesel fuel additive. 15. Use according to embodiment 14 as an additive for reducing the fuel consumption of direct-injection diesel engines, in particular of diesel engines with common rail injection systems, as determined, for example, in an XUD9 test according to CEC-F-23-01, and / or for minimizing power loss in direct-injection diesel engines, in particular in diesel engines with common rail injection systems, as determined, for example, in a DW10 test based on CEC F-098-08. 16. Use according to embodiment 14 as a gasoline fuel additive for reducing deposits in the intake system of a gasoline engine, such as, in particular, DISI (Direct Injection Spark Igniton) and PFI (Port Fuel Injector) engines. 17.Use according to embodiment 14 as a diesel fuel additive, in particular as a cold flow improver, as a wax anti-settling additive (WASA) or as an additive for reducing and / or preventing deposits in injection systems, such as in particular internal diesel injector deposits (IDID) and / or valve sticking in direct-injection diesel engines, in particular in common-rail injection systems. Furthermore described herein, but not forming part of the subject matter of the invention: 18. An additive concentrate comprising, in combination with other diesel or gasoline fuel additives, in particular diesel fuel additives, at least one reaction product or a quaternized nitrogen compound as defined in embodiment 12 or prepared according to embodiment 13. A2) General definitions

[0019] A "condensation" or "condensation reaction" in the sense of the present invention describes the reaction of two molecules with the elimination of a smaller molecule, in particular a water molecule. If such elimination is not analytically detectable, especially in stoichiometric amounts, and the two molecules nevertheless react, e.g., by addition, the reaction in question between the two molecules occurs "without condensation."

[0020] Unless otherwise stated, the following general meanings apply: "Hydrocarbyl" is to be interpreted broadly and includes both long-chain and short-chain, straight-chain and branched hydrocarbon radicals, which may contain additional heteroatoms, such as O, N, NH, or S, in their chain. "Long-chain" or "high molecular weight" hydrocarbyl radicals have a number-average molecular weight (M n ) of 85 to 20,000, such as 113 to 10,000, or 200 to 10,000, or 350 to 5,000, such as 350 to 3,000, 500 to 2,500, 700 to 2,500, or 800 to 1,500. In particular, they are composed essentially of C 2-6 , especially C 2-4 monomer units, such as ethylene, propylene, n- or isobutylene, or mixtures thereof, where the various monomers may be present in random distribution or polymerized as blocks. Such long-chain hydrocarbyl radicals are also referred to as polyalkylene radicals or poly-C 2-6 or poly-C 2-4 alkylene radicals.Suitable long-chain hydrocarbyl radicals and their preparation are also described, for example, in WO2006 / 135881 and the literature cited therein.

[0021] Examples of particularly useful polyalkylene residues are polyisobutenyl residues derived from so-called "highly reactive" polyisobutenes (HR-PIB), which are characterized by a high content of terminally arranged double bonds (see, for example, Rath et al., Lubrication Science (1999), 11-2, 175-185). Terminally arranged double bonds are alpha-olefinic double bonds of the type which together are also referred to as vinylidene double bonds. Suitable highly reactive polyisobutenes are, for example, polyisobutenes which have a proportion of vinylidene double bonds of greater than 70 mol%, in particular greater than 80 mol% or greater than 85 mol%. Polyisobutenes which have uniform polymer backbones are particularly preferred. Uniform polymer backbones are particularly those polyisobutenes which are composed of at least 85% by weight, preferably at least 90% by weight and particularly preferably at least 95% by weight of isobutene units. Such highly reactive polyisobutenes preferably have a number-average molecular weight in the above-mentioned range. In addition, the highly reactive polyisobutenes can have a polydispersity in the range from 1.05 to 7, in particular from about 1.1 to 2.5, such as less than 1.9 or less than 1.5.Polydispersity is the quotient of the weight-average molecular weight Mw divided by the number-average molecular weight Mn.

[0022] Particularly suitable highly reactive polyisobutenes include the Glissopal brands from BASF SE, in particular Glissopal®< 1000 (Mn = 1000), Glissopal®< V 33 (Mn = 550), Glissopal®< 1300 (Mn = 1300), and Glissopal®< 2300 (Mn = 2300), and mixtures thereof. Other number-average molecular weights can be achieved in a manner known in principle by mixing polyisobutenes of different number-average molecular weights or by extractive enrichment of polyisobutenes in specific molecular weight ranges.

[0023] PIBSA is produced in a known manner by reacting PIB with maleic anhydride (MA). This essentially results in a mixture of PIBSA and bismaleic PIBSA (BM PIBSA, see Scheme 1 below), which is generally not used separately but as such in subsequent reactions. The ratio of the two components to each other can be expressed as the "degree of bismaleication" (DMG). The DMG is known per se (see also US Pat. No. 5,883,196). The DMG can also be determined using the following formula: BMG = 100 % × wt − % BM PIBSA / wt − % BM PIBSA + wt − % PIBSA where wt-%(X) is the weight fraction of component X (X = PIBSA or BM PIBSA) in the reaction product of PIB with MSA

[0024] Hydrocarbyl-substituted polycarboxylic acid compounds with a "low degree of bismaleation," in particular corresponding polyisobutenylsuccinic acids or anhydrides thereof (collectively also referred to as PIBSA), are known in the art. Degrees of bismaleation of 20% or less, or 15% or less, such as 14, 13, 12, or 10%, are particularly advantageous; or 10% or less, such as 2-9, 3-8, 4-7, 5, or 6%, are particularly advantageous. Their targeted preparation is described, for example, in US Pat. No. 5,883,196. Particularly suitable for their preparation are the above-mentioned highly reactive polyisobutenes, having a Mn in the range of about 500 to 2500, such as 550 to 3000, 1000 to 2000, or 1000 to 1500.

[0025] As a non-limiting example of a corresponding PIBSA, Glissopal ®< SA, derived from HR-PIB (Mn=1000), with a bismaleation degree of 9% can be mentioned.

[0026] "Short-chain hydrocarbyl" or "low molecular weight hydrocarbyl" particularly represents straight-chain or branched alkyl or alkenyl, optionally interrupted by one or more, such as 2, 3, or 4, heteroatom groups, such as -O- or -NH-, or optionally mono- or polysubstituted, such as 2, 3, or 4-fold.

[0027] "Alkyl" or "lower alkyl" stands in particular for saturated, straight-chain or branched hydrocarbon radicals having 1 to 4, 1 to 6, 1 to 8, or 1 to 10 or 1 to 20 carbon atoms, such as. B. Methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methyl-propyl, 2-methylpropyl, 1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-di-methylpropyl, 1-ethylpropyl, n-hexyl, 1,1-Dimethylpropyl, 1,2-Dimethylpropyl, 1-Methylpentyl, 2-Methylpentyl, 3-Methylpentyl, 4-Methylpentyl, 1,1-Dimethylbutyl, 1,2-Dimethylbutyl, 1,3-Dimethylbutyl, 2,2-Dimethylbutyl, 2,3-Dimethylbutyl, 3,3-Dimethylbutyl, 1-Ethylbutyl, 2-Ethylbutyl, 1,1,2-Trimethylpropyl, 1,2,2-Trimethylpropyl, 1-Ethyl-1-methylpropyl and 1-ethyl-2-methylpropyl; as well as n-heptyl, n-octyl, n-nonyl and n-decyl, as well as the singly or multiply branched analogues thereof.

[0028] "Hydroxyalkyl" stands in particular for the mono- or polyhydroxylated, in particular singly hydroxylated analogues of the above alkyl radicals, such as the monohydroxylated analogues of the above straight-chain or branched alkyl radicals, such as the linear hydroxyalkyl groups with a primary hydroxyl group, such as hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl.

[0029] "Alkenyl" stands for mono- or polyunsaturated, in particular monounsaturated, straight-chain or branched hydrocarbon radicals having 2 to 4, 2 to 6, 2 to 8, 2 to 10 or 2 or to 20 carbon atoms and one double bond in any position, e.g. B. C 2 -C 6 alkenyl such as ethenyl, 1-propenyl, 2-propenyl, 1-methylethenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 1-methyl-2-propenyl, 2-methyl-2-propenyl, 1-Pentenyl, 2-Pentenyl, 3-Pentenyl, 4-Pentenyl, 1-Methyl-1-butenyl, 2-Methyl-1-butenyl, 3-Methyl-1-butenyl, 1-Methyl-2-butenyl, 2-Methyl-2-butenyl, 3-Methyl-2-butenyl, 1-Methyl-3-butenyl, 2-methyl-3-butenyl, 3-Methyl-3-butenyl, 1,1-Dimethyl-2-propenyl, 1,2-Dimethyl-1-propenyl, 1,2-Dimethyl-2-propenyl, 1-Ethyl-1-propenyl, 1-Ethyl-2-propenyl, 1-Hexenyl, 2-Hexenyl, 3-Hexenyl, 4-Hexenyl, 5-Hexenyl, 1-Methyl-1-pentenyl, 2-Methyl-1-pentenyl, 3-Methyl-1-pentenyl, 4-Methyl-1-pentenyl, 1-Methyl-2-pentenyl, 2-Methyl-2-pentenyl, 3-Methyl-2-pentenyl,4-Methyl-2-pentenyl, 1-Methyl-3-pentenyl, 2-Methyl-3pentenyl, 3-Methyl-3-pentenyl, 4-Methyl-3-pentenyl, 1-Methyl-4-pentenyl, 2-Methyl-4-pentenyl, 3-Methyl-4-pentenyl, 4-Methyl-4-pentenyl, 1,1-Dimethyl-2-butenyl, 1,1-Dimethyl-3-butenyl, 1,2-Dimethyl-1-butenyl, 1,2-Dimethyl-2-butenyl, 1,2-Dimethyl-3-butenyl, 1,3-Dimethyl-1-butenyl, 1,3-Dimethyl-2-butenyl, 1,3-Dimethyl-3-butenyl, 2,2-Dimethyl-3-butenyl, 2,3-Dimethyl-1-butenyl, 2,3-Dimethyl-2-butenyl, 2,3-Dimethyl-3-butenyl, 3,3-Dimethyl-1-butenyl, 3,3-Dimethyl-2-butenyl, 1-Ethyl-1-butenyl, 1-Ethyl-2-butenyl, 1-Ethyl-3-butenyl, 2-Ethyl-1-butenyl, 2-Ethyl-2-butenyl, 2-Ethyl-3-butenyl, 1,1,2-Trimethyl-2-propenyl, 1-Ethyl-1-methyl-2-propenyl, 1-Ethyl-2-methyl-1-propenyl und 1-Ethyl-2-methyl-2-propenyl.,

[0030] "Alkylene" stands for straight-chain or singly or multiply branched hydrocarbon bridging groups having 1 to 10 carbon atoms, such as C 1 -C 7 -alkylene groups selected from -CH 2 -, -(CH 2 ) 2 -, -(CH 2 ) 3 -, -CH 2 -CH(CH 3 )-, -CH(CH 3 )-CH 2 -, -(CH 2 ) 4 -, - (CH 2 ) 2 -CH(CH 3 )-, -CH 2 -CH(CH 3 )-CH 2 -, (CH 2 ) 4 -, -(CH 2 ) 5 -, -(CH 2 ) 6 , -(CH 2 ) 7 -, -CH(CH 3 )-CH 2 -CH 2 -CH(CH 3 )- or - CH(CH 3 )-CH 2 -CH 2 -CH 2 -CH(CH 3 )- or C 1 -C 4 -alkylene groups selected from -CH 2 -, -(CH 2 ) 2 -, -(CH 2 ) 3 -, -CH 2 -CH(CH 3 )-, -CH(CH 3 )-CH 2 -, -(CH 2 ) 4 -, -(CH 2 ) 2 -CH(CH 3 )-, -CH 2 -CH(CH 3 )-CH 2 -.

[0031] "Alkenylene" stands for the mono- or polyunsaturated, in particular monounsaturated analogues of the above alkylene groups having 2 to 10 carbon atoms, in particular for C 2 -C 7 -alkenylenes or C 2 -C 4 -alkenylene, such as -CH=CH-, -CH=CH-CH 2 -, -CH 2 -CH=CH-, -CH=CH-CH 2 -CH 2 -, -CH 2 -CH=CH-CH 2 -, -CH 2 -CH 2 -CH=CH-, -CH(CH 3 )-CH=CH-, -CH 2 -C(CH 3 )=CH-.

[0032] "Cyclic hydrocarbyl radicals" include in particular: Cycloalkyl: carbocyclic radicals having 3 to 20 carbon atoms, such as C 3 -C 12 -cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl and cyclododecyl; preferred are cyclopentyl, cyclohexyl, cycloheptyl, and cyclopropyl-methyl, cyclopropyl-ethyl, cyclobutyl-methyl, cyclobutyl-ethyl, cyclopentyl-methyl, cyclopentyl-ethyl, cyclohexylmethyl or C 3 -C 7 -cycloalkyl, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopropyl-methyl, cyclopropyl-ethyl, cyclobutylmethyl, cyclopentyl-ethyl, cyclohexyl-methyl, where the bond to the remainder of the molecule can be made via any suitable C atom.Cycloalkenyl: monocyclic, monounsaturated hydrocarbon groups having 5 to 8, preferably 6, carbon ring members, such as cyclopenten-1-yl, cyclopenten-3-yl, cyclohexen-1-yl, cyclohexen-3-yl, and cyclohexen-4-yl; Aryl: mono- or polynuclear, preferably mono- or binuclear, optionally substituted aromatic radicals having 6 to 20, such as 6 to 10, ring carbon atoms, such as phenyl, biphenyl, naphthyl such as 1- or 2-naphthyl, tetrahydronaphthyl, fluorenyl, indenyl, and phenanthrenyl. These aryl radicals may optionally bear 1, 2, 3, 4, 5, or 6 identical or different substituents.

[0033] "Substituents" for radicals indicated herein are, in particular, unless otherwise stated, selected from keto groups, - COOH, -COO-alkyl, - OH, -SH, -CN, amino, -NO 2 , alkyl, or alkenyl groups.

[0034] The term "approximately" in the context of a numerical specification or a range of values ​​refers to deviations from the specifically disclosed values. These are usually typical deviations. These can vary, for example, by ±10% to ±0.1% from the specifically stated values. Typically, such deviations are approximately ±8% to ±1%, or ±5%, ±4%, ±3%, or ±2%. A3) Polycarboxylic acid compounds and hydrocarbyl-substituted polycarboxylic acid compounds:

[0035] The polycarboxylic acid compounds used are aliphatic di- or polybasic (such as tri- or tetrabasic), in particular di-, tri- or tetracarboxylic acids, and analogues thereof, such as anhydrides or lower alkyl esters (partially or fully esterified), and optionally substituted by one or more (such as 2 or 3), in particular a long-chain alkyl radical and / or a high-molecular-weight hydrocarbyl radical, in particular a polyalkylene radical. Examples are C 3 - C 10 polycarboxylic acids, such as the dicarboxylic acids malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid, and their branched analogues; and the tricarboxylic acid citric acid; and anhydrides or lower alkyl esters thereof. The polycarboxylic acid compounds can also be produced from the corresponding monounsaturated acids and addition of at least one long-chain alkyl radical and / or high-molecular-weight hydrocarbyl radical.Examples of suitable monounsaturated acids are fumaric acid, maleic acid, itaconic acid.

[0036] The hydrophobic "long-chain" or "high molecular weight" hydrocarbyl radical, which ensures sufficient solubility of the quaternized product in the fuel, has a number-average molecular weight (M n ) of 85 to 20,000, such as 113 to 10,000, or 200 to 10,000 or 350 to 5,000, such as 350 to 3,000, 500 to 2,500, 700 to 2,500, or 800 to 1,500. Typical hydrophobic hydrocarbyl radicals are polypropenyl, polybutenyl and polyisobutenyl radicals, e.g. with a number average molecular weight M n of 3,500 to 5,000, 350 to 3,000, 500 to 2,500, 700 to 2,500 and 800 to 1,500.

[0037] Suitable hydrocarbyl substituted compounds are described, for example, in DE 43 19 672 and WO2008 / 138836.

[0038] Suitable hydrocarbyl-substituted polycarboxylic acid compounds also include polymeric, particularly dimeric, forms of such hydrocarbyl-substituted polycarboxylic acid compounds. Dimeric forms contain, for example, two acid anhydride groups, which can be reacted independently of one another with the quaternizable nitrogen compound in the preparation process described here. A4) Quaternizing agent:

[0039] In principle, all alkyl esters of a cycloaromatic or cycloaliphatic mono- or polycarboxylic acid (in particular a mono- or dicarboxylic acid) or an aliphatic polycarboxylic acid (in particular dicarboxylic acid) which are suitable as such can be considered as quaternizing agents.

[0040] In a particular embodiment, however, the quaternization of the at least one quaternizable tertiary nitrogen atom is carried out with at least one quaternizing agent selected from a) Compounds of the general formula 1 are R 1 OC(O)R 2 (1) wherein R 1 is a lower alkyl radical and R 2 is an optionally substituted mononuclear aryl or cycloalkyl radical, the substituent being selected from OH, NH 2 , NO 2 , C(O)OR 3 ; R 1a OC(O)-, wherein R 1a has the meanings given above for R 1 and R 3 is H or R 1 ; or b) compounds of the general formula 2 R 1 OC(O)-AC(O)OR 1a (2) wherein R 1 and R 1a independently of one another represent a lower alkyl radical and A represents hydrocarbylene (such as alkylene or alkenylene). Particularly suitable are compounds of the formula 1 in which R 1 represents a C 1 -, C 2 - or C 3 -alkyl radical and R 2 represents a substituted phenyl radical, where the substituent represents HO- or an ester radical of the formula R 1a OC(O)- which is in the para-, meta- or in particular ortho-position to the radical R 1 OC(O)- on the aromatic ring.

[0041] Particularly suitable quaternizing agents are the lower alkyl esters of salicylic acid, such as methyl salicylate, ethyl salicylate, n- and i-propyl salicylate, and n-, i- or tert-butyl salicylate. A5) Quaternized or quaternizable nitrogen compounds

[0042] The quaternizable nitrogen compounds reactive with the polycarboxylic acid compound are selected from a. Hydroxyalkyl-substituted mono- or polyamines having at least one quaternized (e.g. choline) or quaternizable, primary, secondary or tertiary amino group, b. straight-chain or branched, cyclic, heterocyclic, aromatic or non-aromatic polyamines having at least one primary or secondary (anhydride-reactive) amino group and having at least one quaternized or quaternizable, primary, secondary or tertiary amino group; c. piperazines. The quaternizable nitrogen compounds are particularly selected from d. hydroxyalkyl-substituted primary, secondary, tertiary or quaternary monoamines and hydroxyalkyl-substituted primary, secondary, tertiary or quaternary diamines. e.straight-chain or branched aliphatic diamines having two primary amino groups; di- or polyamines having at least one primary and at least one secondary amino group; di- or polyamines having at least one primary and at least one tertiary amino group; di- or polyamines having at least one primary and at least one quaternary amino group; aromatic carbocyclic diamines having two primary amino groups; aromatic heterocyclic polyamines having two primary amino groups; aromatic or non-aromatic heterocycles having one primary and one tertiary amino group; .

[0043] Examples of suitable "hydroxyalkyl-substituted mono- or polyamines" are those which are provided with at least one, such as 1, 2, 3, 4, 5 or 6, hydroxyalkyl substituted group.

[0044] Examples of "hydroxyalkyl-substituted monoamines" include: N-hydroxyalkyl monoamines, N,N-dihydroxyalkyl monoamines, and N,N,N-trihydroxyalkyl monoamines, where the hydroxyalkyl groups are identical or different and are also defined as above. Hydroxyalkyl stands in particular for 2-hydroxyethyl, 3-hydroxypropyl, or 4-hydroxybutyl.

[0045] Examples of "hydroxyalkyl-substituted polyamines" and especially "hydroxyalkyl-substituted diamines" include (N-hydroxyalkyl)alkylenediamines and N,N-dihydroxyalkylalkylenediamines, where the hydroxyalkyl groups are identical or different and are also defined as above. Hydroxyalkyl represents, in particular, 2-hydroxyethyl, 3-hydroxypropyl, or 4-hydroxybutyl; Alkylene represents, in particular, ethylene, propylene, or butylene.

[0046] Suitable "diamines" are alkylenediamines, as well as their N-alkyl-substituted analogues, such as N-monoalkylated alkylenediamines and N,N- or N,N'-dialkylated alkylenediamines. Alkylene particularly represents straight-chain or branched C 1-7 or C 1-4 alkylene, as defined above. Alkyl particularly represents C 1-4 alkyl as defined above. Examples are in particular ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,4-butylenediamine and isomers thereof, pentanediamine and isomers thereof, hexanediamine and isomers thereof, heptanediamine and isomers thereof, as well as mono- or polyalkylated, such as mono- or di-C 1 -C 4 -alkylated, such as methylated, derivatives of the aforementioned diamine compounds, such as 3-dimethylamino-1-propylamine (DMAPA), N,N-diethylaminopropylamine, and N,N-dimethylaminoethylamine.

[0047] Suitable straight-chain polyamines include, for example, dialkylenetriamine, trialkylenetetramine, tetraalkylenepentamine, pentaalkylenehexamine, and the N-alkyl-substituted analogues thereof, such as N-monoalkylated and N,N- or N,N'-dialkylated alkylenepolyamines. Alkylene represents, in particular, straight-chain or branched C 1-7 or C 1-4 alkylene, as defined above. Alkyl represents, in particular, C 1-4 alkyl as defined above.

[0048] Examples are, in particular, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine, tetrapropylenepentamine, pentapropylenehexamine, dibutylenetriamine, tributylenetetramine, tetrabutylenepentamine, pentabutylenehexamine; and the N,N-dialkyl derivatives thereof, in particular the N,N-di-C 1-4 -alkyl derivatives thereof. Examples include: N,N-dimethyldimethylenetriamine, N,N-diethyldimethylenetriamine, N,N-dipropyldimethylenetriamine, N,N-dimethyldiethylene-1,2-triamine, N,N-diethyldiethylene-1,2-triamine, N,N-dipropyldiethylene-1,2-triamine, N,N-dimethyldipropylene-1,3-triamine (ieDMAPAPA) N,N-diethyldipentylene-1,5-triamine, N,N-dipropyldipentylene-1,5-triamine, N,N-dimethyldihexylene-1,6-triamine, N,N-diethyldihexylene-1,6-triamine and N,N-dipropyldihexylene-1,6-triamine,.

[0049] "Aromatic carbocyclic diamines" with two primary amino groups are the di-amino-substituted derivatives of benzene, biphenyl, naphthalene, tetrahydronaphthalene, fluorene, indene, and phenanthrene.

[0050] "Aromatic or non-aromatic heterocyclic polyamines" with two primary amino groups are the derivatives of the following heterocycles substituted with two amino groups: 5- or 6-membered saturated or monounsaturated heterocycles containing one to two nitrogen atoms and / or one oxygen or sulfur atom or one or two oxygen and / or sulfur atoms as ring members, e.g., tetrahydrofuran, pyrrolidine, isoxazolidine, isothiazolidine, pyrazolidine, oxazolidine, thiazolidine, imidazolidine, pyrroline, piperidine, piperidinyl, 1,3-dioxane, tetrahydropyran, hexahydropyridazine, hexahydropyrimidine, piperazine; 5-membered aromatic heterocycles containing, in addition to carbon atoms, one, two, or three nitrogen atoms or one or two nitrogen atoms and one sulfur or oxygen atom as ring members, e.g., furan, thiane, pyrrole, pyrazole, oxazole, thiazole, imidazole, and 1,3,4-triazole; Isoxazole, isothiazole, thiadiazole, oxadiazole 6-membered heterocycles containing, in addition to carbon atoms, one or two or one, two or three nitrogen atoms as ring members, e.g.pyridinyl, pyridazine, pyrimidine, pyrazinyl, 1,2,4-triazine, 1,3,5-triazin-2-yl; .

[0051] "Aromatic or non-aromatic heterocycles having a primary and a tertiary amino group" are, for example, the above-mentioned N-heterocycles which are aminoalkylated on at least one ring N atom and in particular carry an amino-C 1-4 alkyl group.

[0052] "Aromatic or non-aromatic heterocycles having a tertiary amino group and a hydroxyalkyl group" are, for example, the above-mentioned N-heterocycles which are hydroxyalkylated on at least one ring N atom and in particular carry a hydroxy-C 1-4 alkyl group.

[0053] The following groups of individual classes of quaternizable nitrogen compounds are particularly mentioned: Group 1: NAME FORMULA Diamines with primary second N atom Ethylenediamine 1,2-Propylenediamine 1,3-Propylenediamine Isomeric butylenediamines, such as 1,5-pentylenediamine Isomeric pentanediamines, such as Isomeric hexanediamines, such as Isomeric heptanediamines, such as Di- and polyamines with a secondary second N-atom Diethylenetriamine (DETA) Dipropylenetriamine (DPTA), 3,3'-Iminobis(N,N-dimethylpropylamine) Triethylenetetramine (TETA) Tetraethylenepentamine (TEPA) Pentaethylenehexamine N-Methyl-3-amino-1-propylamine Bishexamethylenetriamine Aromatics Diaminobenzenes, such as Diaminopyridines, such as Group 2: NAME FORMULA Heterocycles 1-(3-Aminopropyl)imidazol 4-(3-Aminopropyl)-morpholine 1-(2-Aminoethylpiperidine) 2-(1-Piperazinyl)ethylamine (AEP) N-Methylpiperazine Amines with a tertiary second N atom 3,3-Diamino-N-methyldipropylamine 3-Dimethylamino-1-propylamine (DMAPA) N,N-Diethylaminopropylamine N,N-Dimethylaminoethylamine Group 3: NAME FORMULA Alcohols with primary and secondary amine Ethanolamine 3-Hydroxy-1-propylamine Diethanolamine Diisopropanolamin N-(2-Hydroxyethyl)ethylenediamine Alcohols with tertiary amine Triethanolamine, (2.2 I<,2 II<-nitrilotriethanol) 1-(3-Hydroxypropyl)imidazol Tris(hydroxymethyl)amine 3-Dimethylamino-1-propanol 3-Diethylamino-1-propanol 2-Dimethylamino-1-ethanol 4-Diethylamino-1-butanol A6) Production of additives used according to the invention: a) Reaction with oxygen or nitrogen group:

[0054] The reaction of the hydrocarbyl-substituted polycarboxylic acid compound with the quaternizable nitrogen compound according to the present invention can be carried out under thermally controlled conditions, so that essentially no condensation reaction occurs. In particular, no formation of water of reaction is then observed. In particular, such a reaction takes place at a temperature in the range of 10 to 80, in particular 20 to 60 or 30 to 50 °C. The reaction time can be in the range of a few minutes or several hours, for example, about 1 minute up to about 10 hours. The reaction can take place at about 0.1 to 2 atm pressure, but in particular at about atmospheric pressure. For example, an inert gas atmosphere, such as nitrogen, is expedient.

[0055] In particular, the reaction can also be carried out at elevated temperatures that favor condensation, e.g., in the range of 90 to 100 °C or 100 to 170 °C. The reaction time can range from a few minutes to several hours, for example, from about 1 minute to about 10 hours. The reaction can take place at a pressure of about 0.1 to 2 atm, but in particular at approximately atmospheric pressure.

[0056] The reactants are preferably initially introduced in approximately equimolar amounts; if necessary, a slight molar excess of the polycarboxylic acid compound, e.g., 0.05 to 0.5 times, such as 0.1 to 0.3 times, is desirable. If necessary, the reactants can be initially introduced in a suitable inert organic aliphatic or aromatic solvent or a mixture thereof. Typical examples are solvents from the Solvesso series, toluene, or xylene. The solvent can also be used, for example, to azeotropically remove condensation water from the reaction mixture. In particular, however, the reactions are carried out without solvent.

[0057] The reaction product thus formed can theoretically be further purified or the solvent removed in a non-inventive embodiment. However, this is usually not absolutely necessary, so the reaction product can be transferred to the next synthesis step, quaternization, without further purification. b) Quaternization The quaternization according to reaction step (b) is now carried out in a manner known per se

[0058] To carry out the quaternization, the reaction product or reaction mixture from step a) is mixed with at least one compound of formula 1 or 2 above, particularly in the required stoichiometric amounts to achieve the desired quaternization. The quaternizing agent is added in excess per equivalent of quaternizable tertiary nitrogen atom, such as 1.25 to 2.0 equivalents of quaternizing agent per equivalent of quaternizable tertiary nitrogen atom.

[0059] The reaction typically takes place at temperatures in the range of 50 to 180°C, such as 90 to 160°C or 100 to 140°C. The reaction time can range from a few minutes to several hours, such as about 10 minutes to about 24 hours. The reaction can take place at a pressure of about 0.1 to 20 bar, such as 1 to 10 or 1.5 to 3 bar, but in particular at approximately atmospheric pressure. If necessary, the reactants can be initially introduced into a suitable inert organic aliphatic or aromatic solvent or a mixture thereof for the quaternization, or a sufficient amount of solvent from reaction step a) is still present. Typical examples are, for example, solvents from the Solvesso series, toluene, or xylene. However, the quaternization can also be carried out in the absence of a solvent.

[0060] To carry out the quaternization, the addition of catalytically effective amounts of an acid may be advantageous. Aliphatic monocarboxylic acids, such as C 1 -C 18 monocarboxylic acids, such as lauric acid, isononanoic acid, or neodecanoic acid, are preferred. The quaternization can also be carried out in the presence of a Lewis acid. However, the quaternization can also be carried out in the absence of any acid. c) Workup of the reaction mixture

[0061] The resulting reaction product can theoretically be further purified in a non-inventive embodiment, or the solvent can be removed. However, to improve the further processability of the products, solvents can also be added after the reaction, such as solvents from the Solvesso series, 2-ethylhexanol, or essentially aliphatic solvents. However, this is usually not absolutely necessary, so the reaction product can be used as an additive without further purification, optionally after blending with other additive components (see below). B) Other additive components

[0062] The fuel additived with the quaternized additive described here is a gasoline fuel or, in particular, a middle distillate fuel, especially a diesel fuel.

[0063] The fuel may contain other common additives to improve efficiency and / or suppress wear.

[0064] In the case of diesel fuels, these are primarily common detergent additives, carrier oils, cold flow improvers, lubricity improvers, corrosion inhibitors, demulsifiers, dehazers, antifoams, cetane number improvers, combustion improvers, antioxidants or stabilizers, antistatic agents, metallocenes, metal deactivators, dyes and / or solvents.

[0065] In the case of gasoline, these are mainly friction modifiers, corrosion inhibitors, demulsifiers, dehazers, antifoam agents, combustion improvers, antioxidants or stabilizers, antistatic agents, metallocenes, metal deactivators, dyes and / or solvents.

[0066] Typical examples of suitable co-additives are listed in the following section: B1) Detergent additives

[0067] The usual detergent additives are preferably amphiphilic substances which have at least one hydrophobic hydrocarbon radical with a number-average molecular weight (M n ) of 85 to 20,000 and at least one polar group selected from: (Da) mono- or polyamino groups with up to 6 nitrogen atoms, where at least one nitrogen atom has basic properties; (Db) nitro groups, optionally in combination with hydroxyl groups; (Dc) hydroxyl groups in combination with mono- or polyamino groups, where at least one nitrogen atom has basic properties; (Dd) carboxyl groups or their alkali metal or alkaline earth metal salts; (De) sulfonic acid groups or their alkali metal or alkaline earth metal salts; (Df) polyoxy-C 2 - to C 4 -alkylene groups terminated by hydroxyl groups, mono- or polyamino groups, where at least one nitrogen atom has basic properties, or by carbamate groups; (Dg) carboxylic acid ester groups; (Dh) groups derived from succinic anhydride with hydroxyl and / or amino and / or amido and / or imido groups; and / or (Di) moieties produced by Mannich reaction of substituted phenols with aldehydes and mono- or polyamines.

[0068] The hydrophobic hydrocarbon radical in the above detergent additives, which ensures sufficient solubility in the fuel, has a number-average molecular weight (M n ) of 85 to 20,000, preferably of 113 to 10,000, particularly preferably of 300 to 5,000, more preferably of 300 to 3,000, even more preferably of 500 to 2,500 and in particular of 700 to 2,500, especially of 800 to 1,500. As a typical hydrophobic hydrocarbon radical, in particular in combination with the polar, in particular polypropenyl, polybutenyl and polyisobutenyl radicals with a number-average molecular weight M n of preferably in each case 300 to 5,000, particularly preferably 300 to 3,000, more preferably 500 to 2,500, more preferably 700 to 2,500 and especially 800 to 1,500.

[0069] The following may be mentioned as examples of the above groups of detergent additives: Additives containing mono- or polyamino groups (Da) are preferably polyalkene mono- or polyalkene polyamines based on polypropene or on highly reactive (i.e. with predominantly terminal double bonds) or conventional (i.e. with predominantly central double bonds) polybutene or polyisobutene with M n = 300 to 5000, particularly preferably 500 to 2500 and in particular 700 to 2500. Such additives based on highly reactive polyisobutene, which can be prepared from the polyisobutene, which can contain up to 20 wt. % n-butene units, by hydroformylation and reductive amination with ammonia, monoamines or polyamines such as dimethylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine, are known in particular from EP-A 244,616 known.If the additives are produced from polybutene or polyisobutene with predominantly central double bonds (usually in the β- and γ-positions), the production route can be either by chlorination and subsequent amination, or by oxidation of the double bond with air or ozone to the carbonyl or carboxyl compound, followed by amination under reductive (hydrogenating) conditions. Amines such as ammonia, monoamines, or the aforementioned polyamines can be used for amination. Corresponding polypropene-based additives are described, in particular, in WO-A 94 / 24231.

[0070] Further special additives containing monoamino groups (Da) are the hydrogenation products of the reaction products of polyisobutenes having an average degree of polymerization P = 5 to 100 with nitrogen oxides or mixtures of nitrogen oxides and oxygen, as described in particular in WO-A 97 / 03946.

[0071] Further special additives containing monoamino groups (Da) are the compounds obtainable from polyisobutene epoxides by reaction with amines and subsequent dehydration and reduction of the amino alcohols, as described in particular in DE-A 196 20 262.

[0072] Additives containing nitro groups (Db), optionally in combination with hydroxyl groups, are preferably reaction products of polyisobutenes having an average degree of polymerization P = 5 to 100 or 10 to 100 with nitrogen oxides or mixtures of nitrogen oxides and oxygen, as described in particular in WO-A96 / 03367 and WO-A 96 / 03479. These reaction products are generally mixtures of pure nitropolyisobutenes (e.g., α,β-dinitropolyisobutene) and mixed hydroxynitropolyisobutenes (e.g., α-nitro-β-hydroxypolyisobutene).

[0073] Additives containing hydroxyl groups in combination with mono- or polyamino groups (Dc) are in particular reaction products of polyisobutene epoxides, obtainable from polyisobutene having preferably predominantly terminal double bonds and having M n = 300 to 5000 with ammonia, mono- or polyamines, as described in particular in EP-A 476 485.

[0074] Additives containing carboxyl groups or their alkali metal or alkaline earth metal salts (Dd) are preferably copolymers of C 2 - to C 40 -olefins with maleic anhydride having a total molecular weight of 500 to 20,000, whose carboxyl groups are fully or partially converted to the alkali metal or alkaline earth metal salts and a remaining residue of the carboxyl groups is converted with alcohols or amines. Such additives are known in particular from EP-A 307 815. Such additives primarily serve to prevent valve seat wear and, as described in WO-A 87 / 01126, can be advantageously used in combination with conventional fuel detergents such as poly(iso)butenamines or polyetheramines.

[0075] Additives containing sulfonic acid groups or their alkali metal or alkaline earth metal salts (De) are preferably alkali metal or alkaline earth metal salts of an alkyl sulfosuccinate, as described in particular in EP-A 639 632. Such additives serve primarily to prevent valve seat wear and can advantageously be used in combination with conventional fuel detergents such as poly(iso)butenamines or polyetheramines.

[0076] Additives containing polyoxy-C 2 -C 4 -alkylene groups (Df) are preferably polyethers or polyetheramines, which are obtainable by reacting C 2 - to C 60 -alkanols, C 6 - to C 30 -alkanediols, mono- or di-C 2 - to C 30 -alkylamines, C 1 - to C 30 -alkylcyclohexanols or C 1 - to C 30 -alkylphenols with 1 to 30 mol of ethylene oxide and / or propylene oxide and / or butylene oxide per hydroxyl group or amino group and, in the case of polyetheramines, by subsequent reductive amination with ammonia, monoamines or polyamines. Such products are described in particular in EP-A 310 875, EP-A 356 725, EP-A 700 985 and US-A 4 877 416. In the case of polyethers, such products also fulfill carrier oil properties. Typical examples are tridecanol or isotridecanol butoxylates, isononylphenol butoxylates, and polyisobutenol butoxylates and propoxylates, as well as the corresponding reaction products with ammonia.

[0077] Additives containing carboxylic acid ester groups (Dg) are preferably esters of mono-, di-, or tricarboxylic acids with long-chain alkanols or polyols, especially those with a minimum viscosity of 2 mm² / s at 100°C, as described in particular in DE-A 38 38 918. Aliphatic or aromatic acids can be used as mono-, di-, or tricarboxylic acids; long-chain representatives with, for example, 6 to 24 carbon atoms are particularly suitable as ester alcohols or polyols. Typical representatives of esters are adipates, phthalates, isophthalates, terephthalates, and trimellitates of isooctanol, isononanol, isodecanol, and isotridecanol. Such products also fulfill carrier oil properties.

[0078] Additives derived from succinic anhydride containing moieties containing hydroxyl and / or amino and / or amido and / or in particular imido groups (Dh) are preferably corresponding derivatives of alkyl- or alkenyl-substituted succinic anhydride and in particular the corresponding derivatives of polyisobutenylsuccinic anhydride, which are obtainable by reacting conventional or highly reactive polyisobutene with M n = preferably 300 to 5000, particularly preferably 300 to 3000, more preferably 500 to 2500, even more preferably 700 to 2500 and in particular 800 to 1500, with maleic anhydride by thermal means in an ene reaction or via the chlorinated polyisobutene.The groups with hydroxyl and / or amino and / or amido and / or imido groups are, for example, carboxylic acid groups, acid amides of monoamines, acid amides of di- or polyamines which, in addition to the amide function, also have free amine groups, succinic acid derivatives with one acid and one amide function, carboximides with monoamines, carboximides with di- or polyamines which, in addition to the imide function, also have free amine groups, or diimides formed by the reaction of di- or polyamines with two succinic acid derivatives. However, in the presence of imido groups D(h), the further detergent additive within the meaning of the present invention is used only up to a maximum of 100% of the weight amount of compounds with a betaine structure. Such fuel additives are generally known and described, for example, in documents (1) and (2).These are preferably the reaction products of alkyl- or alkenyl-substituted succinic acids or derivatives thereof with amines, and particularly preferably the reaction products of polyisobutenyl-substituted succinic acids or derivatives thereof with amines. Of particular interest here are reaction products with aliphatic polyamines (polyalkyleneimines), such as, in particular, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine, which have an imide structure.

[0079] Additives containing (Di) groups produced by the Mannich reaction of substituted phenols with aldehydes and mono- or polyamines are preferably reaction products of polyisobutene-substituted phenols with formaldehyde and mono- or polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or dimethylaminopropylamine. The polyisobutenyl-substituted phenols can originate from conventional or highly reactive polyisobutene with M n = 300 to 5000. Such "polyisobutene Mannich bases" are described in particular in EP-A 831 141.

[0080] One or more of the detergent additives mentioned can be added to the fuel in such an amount that the dosage rate of these detergent additives is preferably 25 to 2500 ppm by weight, in particular 75 to 1500 ppm by weight, especially 150 to 1000 ppm by weight. B2) Carrier oils

[0081] Carrier oils used can be mineral or synthetic. Suitable mineral carrier oils include fractions obtained during petroleum processing, such as brightstock or base oils with viscosities such as SN 500 to 2000, as well as aromatic hydrocarbons, paraffinic hydrocarbons, and alkoxyalkanols. Also suitable is a fraction known as "hydrocrack oil" obtained during mineral oil refining (a vacuum distillate cut with a boiling range of approximately 360 to 500 °C, obtained from natural mineral oil catalytically hydrogenated, isomerized, and dewaxed under high pressure). Blends of the above-mentioned mineral carrier oils are also suitable.

[0082] Examples of suitable synthetic carrier oils are polyolefins (polyalphaolefins or polyinternal olefins), (poly)esters, poly)alkoxylates, polyethers, aliphatic polyetheramines, alkylphenol-initiated polyethers, alkylphenol-initiated polyetheramines and carboxylic acid esters of long-chain alkanols.

[0083] Examples of suitable polyolefins are olefin polymers with M n = 400 to 1800, especially based on polybutene or polyisobutene (hydrogenated or non-hydrogenated).

[0084] Examples of suitable polyethers or polyetheramines are preferably compounds containing polyoxy-C2- to C4-alkylene groups, which are obtainable by reacting C2- to C60-alkanols, C6- to C30-alkanediols, mono- or di-C2- to C30-alkylamines, C1- to C30-alkylcyclohexanols or C1- to C30-alkylphenols with 1 to 30 mol of ethylene oxide and / or propylene oxide and / or butylene oxide per hydroxyl group or amino group and, in the case of polyetheramines, by subsequent reductive amination with ammonia, monoamines or polyamines. Such products are described in particular in EP-A 310 875, EP-A 356 725, EP-A 700 985 and US-A 4,877,416. For example, poly-C 2 - to C 6 -alkylene oxide amines or functional derivatives thereof can be used as polyetheramines.Typical examples are tridecanol or isotridecanol butoxylates, isononylphenol butoxylates as well as polyisobutenol butoxylates and propoxylates as well as the corresponding reaction products with ammonia.

[0085] Examples of carboxylic acid esters of long-chain alkanols include, in particular, esters of mono-, di-, or tricarboxylic acids with long-chain alkanols or polyols, as described in particular in DE-A 38 38 918. Aliphatic or aromatic acids can be used as mono-, di-, or tricarboxylic acids; long-chain representatives with, for example, 6 to 24 carbon atoms are particularly suitable as ester alcohols or polyols. Typical examples of esters are adipates, phthalates, isophthalates, terephthalates, and trimellitates of isooctanol, isononanol, isodecanol, and isotridecanol, e.g., di-(n- or isotridecyl)phthalate.

[0086] Other suitable carrier oil systems are described, for example, in DE-A 38 26 608, DE-A 41 42 241, DE-A 43 09 074, EP-A 452 328 and EP-A 548 617.

[0087] Examples of particularly suitable synthetic carrier oils are alcohol-initiated polyethers having about 5 to 35, preferably about 5 to 30, particularly preferably 10 to 30, and in particular 15 to 30 C 3 - to C 6 -alkylene oxide units, e.g., propylene oxide, n-butylene oxide, and isobutylene oxide units, or mixtures thereof, per alcohol molecule. Non-limiting examples of suitable starter alcohols are long-chain alkanols or long-chain alkyl-substituted phenols, where the long-chain alkyl radical is, in particular, a straight-chain or branched C 6 - to C 18 -alkyl radical. Particular examples include tridecanol and nonylphenol. Particularly preferred alcohol-initiated polyethers are the reaction products (polyetherification products) of monohydric aliphatic C 6 - to C 18 -alcohols with C 3 - to C 6 -alkylene oxides.Examples of monohydric aliphatic C 6 -C 18 alcohols are hexanol, heptanol, octanol, 2-ethylhexanol, nonyl alcohol, decanol, 3-propylheptanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, octadecanol, and their constitutional and positional isomers. The alcohols can be used both in the form of the pure isomers and in the form of technical mixtures. A particularly preferred alcohol is tridecanol. Examples of C 3 - to C 6 -alkylene oxides are propylene oxide, such as 1,2-propylene oxide, butylene oxide, such as 1,2-butylene oxide, 2,3-butylene oxide, isobutylene oxide, or tetrahydrofuran, pentylene oxide, and hexylene oxide. Particularly preferred among these are C 3 - to C 4 -alkylene oxides, ie, propylene oxide such as 1,2-propylene oxide, and butylene oxide such as 1,2-butylene oxide, 2,3-butylene oxide, and isobutylene oxide. Butylene oxide is used specifically.

[0088] Other suitable synthetic carrier oils are alkoxylated alkylphenols, as described in DE-A 10 102 913.

[0089] Special carrier oils are synthetic carrier oils, with the alcohol-started polyethers described above being particularly preferred.

[0090] The carrier oil or the mixture of different carrier oils is added to the fuel in an amount of preferably 1 to 1000 ppm by weight, particularly preferably 10 to 500 ppm by weight and in particular 20 to 100 ppm by weight. B3) Cold flow improvers

[0091] Suitable cold flow improvers are, in principle, any organic compound capable of improving the flow behavior of middle distillate fuels or diesel fuels in cold temperatures. They must ideally exhibit sufficient oil solubility. In particular, the cold flow improvers ("middle distillate flow improvers" ("MDFI") commonly used in middle distillates of fossil origin, i.e., in conventional mineral diesel fuels, are suitable for this purpose. However, organic compounds can also be used that, when used in conventional diesel fuels, partially or predominantly exhibit the properties of a wax anti-settling additive ("WASA"). They can also partially or predominantly act as nucleators. However, mixtures of organic compounds effective as MDFIs and / or WASAs and / or nucleators can also be used.

[0092] Typically, the cold flow improver is selected from: (K1) copolymers of a C 2 - to C 40 -olefin with at least one further ethylenically unsaturated monomer; (K2) comb polymers; (K3) polyoxyalkylenes; (K4) polar nitrogen compounds; (K5) sulfocarboxylic acids or sulfonic acids or derivatives thereof; and (K6) poly(meth)acrylic acid esters.

[0093] Mixtures of different representatives from one of the respective classes (K1) to (K6) as well as mixtures of representatives from different classes (K1) to (K6) can be used.

[0094] Suitable C 2 - to C 40 -olefin monomers for the copolymers of class (K1) are, for example, those having 2 to 20, in particular 2 to 10, carbon atoms, and having 1 to 3, preferably 1 or 2, in particular one carbon-carbon double bond. In the latter case, the carbon-carbon double bond can be arranged either terminally (α-olefins) or internally. However, α-olefins are preferred, particularly preferably α-olefins having 2 to 6 carbon atoms, for example propene, 1-butene, 1-pentene, 1-hexene, and especially ethylene.

[0095] In the copolymers of class (K1), the at least one further ethylenically unsaturated monomer is preferably selected from carboxylic acid alkenyl esters, (meth)acrylic acid esters and other olefins.

[0096] If additional olefins are polymerized, they are preferably higher molecular weight than the above-mentioned C 2 - to C 40 -olefin base monomers. For example, if ethylene or propene is used as the olefin base monomer, C 10 - to C 40 -α-olefins are particularly suitable as additional olefins. In most cases, additional olefins are only polymerized if monomers with carboxylic acid ester functions are also used.

[0097] Suitable (meth)acrylic acid esters are, for example, esters of (meth)acrylic acid with C 1 to C 20 alkanols, in particular C 1 to C 10 alkanols, especially with methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert-butanol, pentanol, hexanol, heptanol, octanol, 2-ethylhexanol, nonanol and decanol as well as structural isomers thereof.

[0098] Suitable carboxylic acid alkenyl esters are, for example, C 2 - to C 14 -alkenyl esters, e.g., the vinyl and propenyl esters, of carboxylic acids having 2 to 21 carbon atoms, whose hydrocarbon radical may be linear or branched. Vinyl esters are preferred. Among the carboxylic acids with a branched hydrocarbon radical, those whose branching is located in the α-position to the carboxyl group are preferred, with the α-carbon atom particularly preferably being tertiary, i.e., the carboxylic acid is a so-called neocarboxylic acid. However, the hydrocarbon radical of the carboxylic acid is preferably linear.

[0099] Examples of suitable alkenyl carboxylic acid esters are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl neopentanoate, vinyl hexanoate, vinyl neononanoate, vinyl neodecanoate, and the corresponding propenyl esters, with vinyl esters being preferred. A particularly preferred alkenyl carboxylic acid ester is vinyl acetate; typical resulting copolymers of group (K1) are the most frequently used ethylene-vinyl acetate copolymers ("EVA"). Particularly advantageously usable ethylene-vinyl acetate copolymers and their preparation are described in WO 99 / 29748.

[0100] Also suitable as copolymers of class (K1) are those containing two or more different alkenyl carboxylic acid esters in copolymerized form, which differ in the alkenyl function and / or the carboxylic acid group. Copolymers containing, in addition to the alkenyl carboxylic acid ester(s), at least one olefin and / or at least one (meth)acrylic acid ester in copolymerized form are also suitable.

[0101] Terpolymers of a C 2 - to C 40 -α-olefin, a C 1 - to C 20 -alkyl ester of an ethylenically unsaturated monocarboxylic acid having 3 to 15 carbon atoms, and a C 2 - to C 14 -alkenyl ester of a saturated monocarboxylic acid having 2 to 21 carbon atoms are also suitable as copolymers of class (K1). Such terpolymers are described in WO 2005 / 054314. A typical terpolymer of this type is composed of ethylene, 2-ethylhexyl acrylate, and vinyl acetate.

[0102] The at least one or more ethylenically unsaturated monomers are copolymerized into the copolymers of class (K1) in an amount of preferably 1 to 50 wt.%, in particular 10 to 45 wt.%, and especially 20 to 40 wt.%, based on the total copolymer. The majority by weight of the monomer units in the copolymers of class (K1) thus generally originates from the C 2 to C 40 base olefins.

[0103] The copolymers of class (K1) preferably have a number-average molecular weight M n of 1000 to 20,000, particularly preferably of 1000 to 10,000 and in particular of 1000 to 8000.

[0104] Typical comb polymers of component (K2) are obtainable, for example, by copolymerizing maleic anhydride or fumaric acid with another ethylenically unsaturated monomer, for example, with an α-olefin or an unsaturated ester such as vinyl acetate, followed by esterification of the anhydride or acid function with an alcohol having at least 10 carbon atoms. Other suitable comb polymers are copolymers of α-olefins and esterified comonomers, for example, esterified copolymers of styrene and maleic anhydride or esterified copolymers of styrene and fumaric acid. Suitable comb polymers can also be polyfumarates or polymaleates. Homo- and copolymers of vinyl ethers are also suitable comb polymers. Comb polymers suitable as components of class (K2) include, for example, those described in WO 2004 / 035715 and in "Comb-Like Polymers. Structure and Properties," NA Platé and VP Shibaev, J. Poly. Sci. Macromolecular Revs.8, pages 117 to 253 (1974). Mixtures of comb polymers are also suitable.

[0105] Polyoxyalkylenes suitable as components of class (K3) include, for example, polyoxyalkylene esters, polyoxyalkylene ethers, mixed polyoxyalkylene ester-ethers, and mixtures thereof. These polyoxyalkylene compounds preferably contain at least one, preferably at least two, linear alkyl groups, each having 10 to 30 carbon atoms, and one polyoxyalkylene group with a number-average molecular weight of up to 5000. Such polyoxyalkylene compounds are described, for example, in EP-A 061 895 and in US Pat. No. 4,491,455. Particular polyoxyalkylene compounds are based on polyethylene glycols and polypropylene glycols with a number-average molecular weight of 100 to 5000. Polyoxyalkylene mono- and diesters of fatty acids having 10 to 30 carbon atoms, such as stearic acid or behenic acid, are also suitable.

[0106] Polar nitrogen compounds suitable as components of class (K4) can be both ionic and non-ionic in nature and preferably have at least one, in particular at least two substituents in the form of a tertiary nitrogen atom of the general formula >NR 7<, wherein R 7< represents a C 8 - to C 40 -hydrocarbon radical. The nitrogen substituents can also be quaternized, i.e. in cationic form. Examples of such nitrogen compounds are ammonium salts and / or amides, which are obtainable by reacting at least one amine substituted by at least one hydrocarbon radical with a carboxylic acid having 1 to 4 carboxyl groups or with a suitable derivative thereof. The amines preferably contain at least one linear C 8 - to C 40 -alkyl radical.Suitable primary amines for the preparation of the polar nitrogen compounds mentioned include octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tetradecylamine, and the higher linear homologues. Suitable secondary amines include dioctadecylamine and methylbehenylamine. Amine mixtures are also suitable for this purpose, particularly industrially accessible amine mixtures such as fatty amines or hydrogenated tall amines, as described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 6th edition, in the chapter "Amines, Aliphatic." Acids suitable for the reaction include cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, naphthalenedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, and succinic acids substituted with long-chain hydrocarbon radicals.

[0107] In particular, the component of class (K4) is an oil-soluble reaction product of poly(C 2 - to C 20 -carboxylic acids) containing at least one tertiary amino group with primary or secondary amines. The poly(C 2 - to C 20 -carboxylic acids) containing at least one tertiary amino group on which this reaction product is based preferably contain at least 3 carboxyl groups, in particular 3 to 12, especially 3 to 5 carboxyl groups. The carboxylic acid units in the polycarboxylic acids preferably have 2 to 10 carbon atoms, in particular they are acetic acid units. The carboxylic acid units are linked in a suitable manner to the polycarboxylic acids, usually via one or more carbon and / or nitrogen atoms. They are preferably bonded to tertiary nitrogen atoms, which, in the case of multiple nitrogen atoms, are linked via hydrocarbon chains.

[0108] Preferably, the component of class (K4) is an oil-soluble reaction product based on poly(C 2 - to C 20 -carboxylic acids) of the general formula IIa or IIb containing at least one tertiary amino group in which the variable A is a straight-chain or branched C 2 - to C 6 -alkylene group or the grouping of the formula III and the variable B denotes a C 1 to C 19 alkylene group. The compounds of general formula IIa and IIb exhibit, in particular, the properties of a WASA.

[0109] Furthermore, the preferred oil-soluble reaction product of component (K4), in particular that of the general formula IIa or IIb, is an amide, an amide ammonium salt or an ammonium salt in which no, one or more carboxylic acid groups are converted into amide groups.

[0110] Examples of straight-chain or branched C 2 - to C 6 -alkylene groups of the variable A are 1,1-ethylene, 1,2-propylene, 1,3-propylene, 1,2-butylene, 1,3-butylene, 1,4-butylene, 2-methyl-1,3-propylene, 1,5-pentylene, 2-methyl-1,4-butylene, 2,2-dimethyl-1,3-propylene, 1,6-hexylene (hexamethylene), and especially 1,2-ethylene. The variable A preferably comprises 2 to 4, in particular 2 or 3, carbon atoms.

[0111] C1 to C19 alkylene groups of the variable B are, for example, 1,2-ethylene, 1,3-propylene, 1,4-butylene, hexamethylene, octamethylene, decamethylene, dodecamethylene, tetradecamethylene, hexadecamethylene, octadecamethylene, nonadecamethylene, and especially methylene. The variable B preferably comprises 1 to 10, in particular 1 to 4, carbon atoms.

[0112] The primary and secondary amines used as reaction partners for the polycarboxylic acids to form component (K4) are typically monoamines, especially aliphatic monoamines. These primary and secondary amines can be selected from a variety of amines bearing hydrocarbon radicals, optionally linked to one another.

[0113] These amines underlying the oil-soluble reaction products of component (K4) are usually secondary amines and have the general formula HN(R 8< ) 2 , in which the two variables R 8< independently of one another each represent straight-chain or branched C 10 - to C 30 -alkyl radicals, in particular C 14 - to C 24 -alkyl radicals. These longer-chain alkyl radicals are preferably straight-chain or only slightly branched. As a rule, the said secondary amines are derived, with regard to their longer-chain alkyl radicals, from naturally occurring fatty acids or their derivatives. The two radicals R 8< are preferably identical.

[0114] The secondary amines mentioned can be bonded to the polycarboxylic acids via amide structures or in the form of ammonium salts; it is also possible for only a portion to be present as amide structures and another portion as ammonium salts. Preferably, only a few or no free acid groups are present. The oil-soluble reaction products of component (K4) are preferably present entirely in the form of amide structures.

[0115] Typical examples of such components (K4) are reaction products of nitrilotriacetic acid, ethylenediaminetetraacetic acid, or propylene-1,2-diaminetetraacetic acid, each containing 0.5 to 1.5 mol per carboxyl group, in particular 0.8 to 1.2 mol per carboxyl group, dioleylamine, dipalmitinamine, dicoconut fatty amine, distearylamine, dibehenylamine, or, in particular, ditallow fatty amine. A particularly preferred component (K4) is the reaction product of 1 mol of ethylenediaminetetraacetic acid and 4 mol of hydrogenated ditallow fatty amine.

[0116] Further typical examples of component (K4) are the N,N-dialkylammonium salts of 2-N',N'-dialkylamidobenzoates, for example the reaction product of 1 mol of phthalic anhydride and 2 mol of ditallow fatty amine, the latter being hydrogenated or non-hydrogenated, and the reaction product of 1 mol of an alkenylspirobislactone with 2 mol of a dialkylamine, for example ditallow fatty amine and / or tallow fatty amine, the latter two being hydrogenated or non-hydrogenated.

[0117] Other typical structural types for the component of class (K4) are cyclic compounds with tertiary amino groups or condensates of long-chain primary or secondary amines with carboxylic acid-containing polymers, as described in WO 93 / 18115.

[0118] Sulfocarboxylic acids, sulfonic acids or their derivatives suitable as cold flow improvers of the component of class (K5) are, for example, the oil-soluble carboxylic acid amides and carboxylic acid esters of ortho-sulfobenzoic acid in which the sulfonic acid function is present as a sulfonate with alkyl-substituted ammonium cations, as described in EP-A 261 957.

[0119] Poly(meth)acrylic acid esters suitable as cold flow improvers for the component of class (K6) include both homopolymers and copolymers of acrylic and methacrylic acid esters. Copolymers of at least two different (meth)acrylic acid esters that differ in the condensed alcohol are preferred. Optionally, the copolymer also contains a further, different, olefinically unsaturated monomer as copolymerized units. The weight-average molecular weight of the polymer is preferably 50,000 to 500,000. A particularly preferred polymer is a copolymer of methacrylic acid and methacrylic acid esters of saturated C14 and C15 alcohols, the acid groups being neutralized with hydrogenated tallamine. Suitable poly(meth)acrylic acid esters are described, for example, in WO 00 / 44857.

[0120] The cold flow improver or the mixture of various cold flow improvers is added to the middle distillate fuel or diesel fuel in a total amount of preferably 10 to 5000 ppm by weight, particularly preferably 20 to 2000 ppm by weight, more preferably 50 to 1000 ppm by weight and in particular 100 to 700 ppm by weight, e.g. 200 to 500 ppm by weight. B4) Lubricity improvers

[0121] Suitable lubricity improvers (or friction modifiers) are typically based on fatty acids or fatty acid esters. Typical examples are tall oil fatty acid, as described, for example, in WO 98 / 004656, and glycerol monooleate. The reaction products of natural or synthetic oils, such as triglycerides, and alkanolamines described in US Pat. No. 6,743,266 B2 are also suitable as such lubricity improvers. B5) Corrosion inhibitors

[0122] Suitable corrosion inhibitors are, for example, succinic acid esters, especially with polyols, fatty acid derivatives, e.g. oleic acid esters, oligomerized fatty acids, substituted ethanolamines and products sold under the trade name RC 4801 (Rhein Chemie Mannheim, Germany) or HiTEC 536 (Ethyl Corporation). B6) Demulsifiers

[0123] Suitable demulsifiers are, for example, the alkali or alkaline earth metal salts of alkyl-substituted phenol and naphthalene sulfonates and the alkali or alkaline earth metal salts of fatty acids, as well as neutral compounds such as alcohol alkoxylates, e.g. alcohol ethoxylates, phenol alkoxylates, e.g. tert-butylphenol ethoxylate or tert-pentylphenol ethoxylate, fatty acids, alkylphenols, condensation products of ethylene oxide (EO) and propylene oxide (PO), e.g. also in the form of EO / PO block copolymers, polyethyleneimines or polysiloxanes. B7) Dehazer

[0124] Suitable dehazers are, for example, alkoxylated phenol-formaldehyde condensates, such as the products available under the trade name NALCO 7D07 (Nalco) and TOLAD 2683 (Petrolite). B8) Antifoam agents

[0125] Suitable antifoam agents are, for example, polyether-modified polysiloxanes, such as the products available under the trade names TEGOPREN 5851 (Goldschmidt), Q 25907 (Dow Corning) and RHODOSIL (Rhone Poulenc). B9) Cetane number improvers

[0126] Suitable cetane number improvers include aliphatic nitrates such as 2-ethylhexyl nitrate and cyclohexyl nitrate as well as peroxides such as di-tert-butyl peroxide. B10) Antioxidants

[0127] Suitable antioxidants include substituted phenols such as 2,6-di-tert.-butylphenol and 6-di-tert.-butyl-3-methylphenol as well as phenylenediamines such as N,N'-di-sec.-butyl-p-phenylenediamine. B11) Metal deactivators

[0128] Suitable metal deactivators include salicylic acid derivatives such as N,N'-disalicylidene-1,2-propanediamine. B12) Solvent

[0129] Suitable solvents include nonpolar organic solvents such as aromatic and aliphatic hydrocarbons, such as toluene, xylenes, white spirit, and products sold under the trade names SHELLSOL (Royal Dutch / Shell Group) and EXXSOL (ExxonMobil), as well as polar organic solvents, such as alcohols such as 2-ethylhexanol, decanol, and isotridecanol. Such solvents usually enter diesel fuel together with the aforementioned additives and co-additives intended to dissolve or dilute them for improved handling. C) Fuels

[0130] The additive described here is ideally suited as a fuel additive and can, in principle, be used in any fuel. It has a wide range of beneficial effects when operating combustion engines with fuels. The quaternized additive described here is preferably used in middle distillate fuels, especially diesel fuels.

[0131] The present invention therefore also provides fuels, in particular middle distillate fuels, with an effective content of the quaternized additive described here as an additive for achieving advantageous effects during the operation of internal combustion engines, for example diesel engines, in particular direct-injection diesel engines, especially diesel engines with common-rail injection systems. This effective content (dosage rate) is generally from 10 to 5000 ppm by weight, preferably from 20 to 1500 ppm by weight, in particular from 25 to 1000 ppm by weight, especially from 30 to 750 ppm by weight, in each case based on the total amount of fuel.

[0132] Middle distillate fuels such as diesel fuels or heating oils are preferably petroleum raffinates, which typically have a boiling range of 100 to 400°C. These are usually distillates with a 95% boiling point of up to 360°C or even higher. However, they can also be so-called "ultra-low sulfur diesel" or "city diesel," characterized by a 95% boiling point of, for example, a maximum of 345°C and a sulfur content of a maximum of 0.005 wt.%, or by a 95% boiling point of, for example, 285°C and a sulfur content of a maximum of 0.001 wt.%. In addition to the mineral middle distillate fuels or diesel fuels obtainable through refining, those obtainable through coal gasification or gas liquefaction [gas to liquid (GTL) fuels] or biomass liquefaction [biomass to liquid (BTL) fuels] are also suitable. Mixtures of the middle distillate fuels mentioned above are also suitable.Diesel fuels with renewable fuels such as biodiesel or bioethanol.

[0133] The qualities of heating oils and diesel fuels are specified in more detail in DIN 51603 and EN 590, for example (see also Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, Volume A12, p. 617 ff.).

[0134] In addition to its use in the above-mentioned middle distillate fuels of fossil, vegetable, or animal origin, which are essentially hydrocarbon mixtures, the quaternized additive described here can also be used in mixtures of such middle distillates with biofuel oils (biodiesel). Such mixtures are also encompassed by the term "middle distillate fuel" within the meaning of the present invention. They are commercially available and usually contain the biofuel oils in minor amounts, typically in amounts of 1 to 30 wt.%, in particular 3 to 10 wt.%, based on the total amount of middle distillate of fossil, vegetable, or animal origin and biofuel oil.

[0135] Biofuel oils are generally based on fatty acid esters, preferably essentially on alkyl esters of fatty acids derived from vegetable and / or animal oils and / or fats. Alkyl esters are typically understood to be lower alkyl esters, in particular C 1 - to C 4 -alkyl esters, which are obtainable by transesterification of the glycerides, in particular triglycerides, found in vegetable and / or animal oils and / or fats using lower alcohols, for example, ethanol or especially methanol ("FAME"). Typical lower alkyl esters based on vegetable and / or animal oils and / or fats that are used as biofuel oil or components therefor include sunflower methyl ester, palm oil methyl ester ("PME"), soybean oil methyl ester ("SME"), and especially rapeseed oil methyl ester ("RME").

[0136] The middle distillate fuels or diesel fuels are particularly preferably those with a low sulfur content, that is to say 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.

[0137] All commercially available gasoline compositions are suitable. A typical example is the commercially available Eurosuper base fuel according to EN 228. Furthermore, gasoline compositions specified in WO 00 / 47698 are also possible applications for the present invention.

[0138] The quaternized additive described here is particularly suitable as a fuel additive in fuel compositions, especially in diesel fuels, to overcome the problems described above in direct-injection diesel engines, especially those with common-rail injection systems.

[0139] The invention will now be described in more detail using the following exemplary embodiments. The test methods described herein are not limited to the specific exemplary embodiments but are part of the general disclosure of the description and are generally applicable within the scope of the present invention. Experimental part: A. General test methods Engine test b1) XUD9 Test - Determination of Flow Restriction

[0140] The implementation is carried out according to the standard provisions of CEC F-23-01. b2) DW10 - Keep Clean Test

[0141] To investigate the influence of the compounds described here on the performance of direct-injection diesel engines, the power loss was determined based on the official test method CEC F-098-08. Power loss is a direct measure of deposit formation in the injectors.

[0142] The Keep Clean test is based on the CEC test procedure F-098-08 Issue 5. The same test setup and engine type (PEUGEOT DW10) are used as in the CEC procedure.

[0143] Special features of the test used: a) Injectors

[0144] Cleaned injectors were used in the tests. The cleaning time in an ultrasonic bath containing 60°C water + 10% Superdecontamine (Intersciences, Brussels) was 4 hours. b) Test run times

[0145] The test period was 12 hours without downtime. The one-hour test cycle (see the following table) from CEC F-098-08 was run 12 times. Level Duration (minutes) Engine speed (rpm) + / -20 Load (%) Torque (Nm) + / -5 Charge air temperature after intercooler (°C) + / -3 1 2 1750 (20) 62 45 2 7 3000 (60) 173 50 3 2 1750 (20) 62 45 4 7 3500 (80) 212 50 5 2 1750 (20) 62 45 6 10 4000 100 * 50 7 2 1250 (10) 25 43** 8 7 3000 100 * 50 9 2 1250 (10) 25 43** 10 10 2000 100 * 50 11 2 1250 (10) 25 43** 12 7 4000 100 * 50 Σ = 1 h * for expected range see CEC-098-08 ** Target value c) Determination of performance

[0146] The initial power (Po, KC [kW]) is calculated from the measured torque at 4000 rpm full load immediately after the test start and engine warm-up. The procedure is described in Issue 5 of the CEC F-98-08 test procedure. The same test setup and the PEUGEOT DW10 engine type are used.

[0147] The final power (P end , KC) is determined in the 12th cycle at stage 12 (see table above). Here, too, the operating point is 4000 rpm at full load. P end , KC [kW] is calculated from the measured torque.

[0148] The power loss in the KC is calculated as follows: Powerloss , KC % = 1 − P end , KC / P 0 , KC × 100

[0149] A commercially available diesel fuel from Haltermann (RF-06-03) was used as the fuel. 1 ppm by weight of zinc in the form of a zinc neodecanoate solution was added to artificially stimulate the formation of deposits on the injectors. B. Manufacturing examples: Reactants used:

[0150] PIBSA: Produced from maleic anhydride and PIB 1000 in a conventional manner. For the following preparation examples and comparative examples, grades with saponification numbers in the range of 84-95 mg KOH / g were used. DMAPA was used with the respective PIBSA grade in a 1:1 molar ratio, depending on the saponification number. The PIBSA grades used had bismaleic acid concentrations (BMG) of less than 15%. DMAPA: M = 102,18 Methyl salicylate: M = 152,14 Dimethyl phthalate: M = 194,19 Dimethyl oxalate: M = 118,09 Dimethyl sulfate: M = 126,13 Dimethyl carbonate M = 90,08 Preparation Example 1: Synthesis of a quaternized succinimide (PIBSA / DMAPA / dimethyl phthalate)

[0151] Polyisobutylene succinic anhydride (1659 g) is Solvent Naphta Heavy (SNH, Exxon Mobil, CAS64742-95-5 ) (1220 g) is dissolved, and 3-dimethylamino-1-propylamine (DMAPA; 153 g) is added. The reaction solution is stirred at 170°C for 8 h, during which any condensation water formed is continuously distilled off. The PIBSA-DMAPA succinimide is obtained as a solution in solvent naphtha heavy (TBN 0.557 mmol / g).

[0152] A portion of this PIBSA-DMAPA succinimide solution (181 g) is added to dimethyl phthalate (19.4 g), and the resulting reaction solution is stirred for 11 h at 120°C and then for 24 h at 150°C. After cooling to room temperature, the ammonium carboxylate product is obtained as a solution in solvent naphtha heavy. 1< H NMR analysis confirms quaternization. Preparation Example 2: Synthesis of a quaternized suocinimide (PIBSA / DMAPA / methyl salicylate)

[0153] Polyisobutylene succinic anhydride (PIBSA; 2198 g) is heated to 110°C, and 3-dimethylamino-1-propylamine (DMAPA; 182 g) is added over 40 minutes, during which the reaction mixture warms to 140°C. The reaction mixture is heated to 170°C and held at this temperature for 3 hours, during which 28 g of distillate is collected. The PIBSA-DMAPA succinimide is obtained as a viscous oil (TBN 0.735 mmol / g).

[0154] A mixture of this PIBSA-DMAPA succinimide (284.5 g), methyl salicylate (65.5 g) (i.e., approximately 2 equivalents of methyl salicylate per equivalent of tertiary amino group), and 3,3,5-trimethylhexanoic acid (BASF) (0.75 g) is heated to 140-150°C, and the reaction mixture is stirred at this temperature for 6 h. After cooling to room temperature, the product obtained is ammonium salicylate as a viscous oil. 1< H-NMR analysis confirms quaternization. The active ingredient content of the solution is adjusted to 50 wt.% by adding Pilot 900 Oil (Petrochem Carless Ltd.). Preparation Example 3: Synthesis of a quaternized suocinimide (PIBSA / DMAPA / dimethyl oxalate)

[0155] Polyisobutylene succinic anhydride (PIBSA; 2198 g) is heated to 110°C, and 3-dimethylamino-1-propylamine (DMAPA; 182 g) is added over 40 minutes, during which the reaction mixture warms to 140°C. The reaction mixture is heated to 170°C and held at this temperature for 3 hours, during which 28 g of distillate is collected. The PIBSA-DMAPA succinimide is obtained as a viscous oil (TBN 0.735 mmol / g).

[0156] A mixture of this PIBSA-DMAPA succinimide (211 g), dimethyl oxalate (34.5 g), and lauric acid (4.9 g) was heated to 120°C and then stirred at this temperature for 4 h. Excess dimethyl oxalate was removed on a rotary evaporator under vacuum (p = 5 mbar) at 120°C. The product obtained was ammonium methyl oxalate as a viscous oil. 1< H NMR analysis confirmed quaternization.

[0157] For comparison with the state of the art, examples 2 and 4 from WO 2006 / 135881 were reworked. Preparation Example 4: Synthesis of a known quaternized succinimide (comparison example) (Example 2 from WO 2006 / 135881)

[0158] A solution of PIBSA (420.2 g) in Pilot 900 oil (Petrochem Carless Ltd.) (51.3 g) is initially introduced and heated to 110°C. DMAPA (31.4 g) is added over a period of 50 minutes, during which a slightly exothermic reaction is observed. The reaction mixture is heated to 150°C over a period of 80 minutes, and the reaction mixture is then held at this temperature for 3 hours, during which the resulting water of reaction is distilled off. After cooling to room temperature, the PIBSA-DMAPA succinimide is obtained as a solution in Pilot 900 oil (TBN 0.62 mmol / g).

[0159] A portion of the resulting PIBSA-DMAPA succinimide solution in Pilot 900 oil (Petrochem Carless Ltd.) (354 g) is initially introduced and heated to 90°C. Dimethyl sulfate (26.3 g) is added, causing the reaction temperature to rise to 112°C. The reaction mixture is then stirred at 100°C for 3 h. After cooling to room temperature, the quaternized PIBSA-DMAPA succinimide is obtained as a solution in Pilot 900 oil. 1< H NMR analysis confirmed the quaternization. The effluent was adjusted to an active ingredient content of 50 wt. % by adding Pilot 900 oil. Preparation Example 5: Synthesis of a known quaternized succinimide (comparative example) (Example 4 from WO 2006 / 135881)

[0160] A solution of PIBSA (420.2 g) in Pilot 900 oil (Petrochem Carless Ltd.) (51.3 g) is initially introduced and heated to 110°C. DMAPA (31.4 g) is added over a period of 50 minutes, during which a slightly exothermic reaction is observed. The reaction mixture is heated to 150°C over a period of 80 minutes, and the reaction mixture is then held at this temperature for 3 hours, during which the resulting water of reaction is distilled off. After cooling to room temperature, the PIBSA-DMAPA succinimide is obtained as a solution in Pilot 900 oil (TBN 0.62 mmol / g).

[0161] A portion of the resulting PIBSA-DMAPA-succinimide solution in Pilot 900 oil (Petrochem Carless Ltd.) (130 g), dimethyl carbonate (20 g), and methanol (17.4 g) are charged into an autoclave, inertized with nitrogen, and set to a pre-pressure of 1.3 bar. The reaction mixture is then stirred under autogenous pressure, first at 90°C for 1 h, then at 140°C for 24 h. After cooling to room temperature, the autoclave is depressurized, and the contents are completely rinsed out using a small amount of toluene as solvent. All low-boiling components are then removed under vacuum using a rotary evaporator, yielding the quaternized PIBSA-DMAPA-succinimide solution in Pilot 900 oil. 1< H NMR analysis confirmed partial quaternization. The effluent is adjusted to an active ingredient content of 50 wt.% by addition of Pilot 900 oil. C. Application examples:

[0162] In the following application examples, the additives are used either as pure substances (as synthesized in the above production examples) or in the form of an additive package. M1 : Additive according to Preparation Example 2 (quaternized with methyl salicylate) M2 : Additive according to Preparation Example 4 (comparison, quaternized with dimethyl sulfate) M3 : Additive according to Preparation Example 5 (comparison, quaternized with dimethyl carbonate) Application example 1: Determination of the additive effect on the formation of deposits in diesel engine injectors a) XUD9 tests

[0163] Fuel used: RF-06-03 (reference diesel, Haltermann Products, Hamburg) The results are summarized in Table 1. Table 1: XUD9 tests e.g. Designation Dosage according to manufacturing example [mg / kg] Flow restriction 0.1 mm needle stroke [%] #1 M1, according to production example 2 30 10.7 #2. M2, according to production example 4 30 48.5 #3 M3, according to manufacturing example 5 30 20.8

[0164] It was shown that the additive M1 has an improved effect compared to the state of the art (M2, M3) at the same dosage. b) DW10 test

[0165] To investigate the influence of the compound described here on the performance of direct-injection diesel engines, the power loss was determined based on the official test method CEC-098-08 as described above. Power loss is a direct measure of deposit formation in the injectors. A standard direct-injection diesel engine with a common-rail system was used.

[0166] A commercially available diesel fuel from Haltermann (RF-06-03) was used as the fuel. 1 ppm by weight of zinc in the form of a zinc didodecanoate solution was added to artificially stimulate the formation of deposits on the injectors.

[0167] The following table shows the results of the relative power loss measurements at 4000 rpm after 12 hours of continuous operation without interruption. The value P 0 indicates the power after 10 minutes, and the value P end indicates the power at the end of the measurement:

[0168] The test results are shown in Table 2. Table 2: Results of the DW10 test Additive Dose [mg / kg] Time [h] Po [KW] Pend [KW] Power loss Basic value 0 12 99.3 94.3 5.0% M1, according to production example 2 160 12 98.7 97.4 1.32% M2, according to production example 4 160 12 99 98.1 0.9 % M3, according to production example 5 160 12 98.1 95.7 2.4 %

[0169] It is shown that the additive M1 has an improved effect compared to the base value and at least an improved effect compared to example M3. Application example 2: Determination of solubility properties

[0170] To determine the solubility properties, the following additive packages were prepared and tested: M 4 substance Content [ppm] Additive according to production example 2 160,00 Dehazer, commercial 3,00 Antifoam, silicon based, commercial 6,00 Solvent Naphtha Heavy 80,00 In total 249,00 M 5 (comparison, dimethyl sulfate) substance Content [ppm] Additive according to production example 4 160,00 Dehazer, commercial 3,00 Antifoam, silicone based, commercial 6,00 Solvent Naphtha Heavy 420,00 In total 589,00 M 6 (comparison, dimethyl carbonate) substance Content [ppm] Additive according to manufacturing example 5 160,00 Dehazer (commercial) 3,00 Antifoam, silicone based, commercial 6,00 Solvent Naphtha Heavy 150,00 In total 319,00

[0171] The results of the solubility tests are summarized in the following table: The minimum amount of solvent (Solvent Naphtha Heavy) required to obtain a homogeneous, clear diesel performance package at room temperature with otherwise identical amounts of active ingredient, Pilot 900, antifoam, and dehazer is given. Table 3: Determination of solvent requirements Additive Additive package Minimum amount of solvent required for a homogeneous package PIBSA-DMAPA-imide methyl salicylate M4 32 % PIBSA-DMAPA-imide dimethyl sulfate M5 71% PIBSA-DMAPA-imide dimethyl carbonate M6 47%

[0172] Surprisingly, it was found that the additive according to Preparation Example 2 has the best solubility properties, i.e. requires the least solvent.

[0173] The disclosure of the publications cited herein is expressly incorporated by reference.

Claims

1. A fuel composition comprising, in a majority of a customary fuel, a proportion of at least one reaction product comprising a quaternized nitrogen compound, said reaction product being obtainable by a1) reacting a hydrocarbyl-substituted polycarboxylic acid compound with a compound comprising at least one oxygen or nitrogen group reactive, especially capable of addition or condensation, with the polycarboxylic acid, and comprising at least one quaternizable amino group, to obtain a quaternizable hydrocarbyl-substituted polycarboxylic acid compound, and a2) subsequent reaction thereof with a quaternizing agent which converts the at least one quaternizable amino group to a quaternary ammonium group, said quaternizing agent being the alkyl ester of a cycloaromatic or cycloaliphatic mono- or polycarboxylic acid, especially of a mono- or dicarboxylic acid, or of an aliphatic polycarboxylic acid; or b) reacting a quaternizable hydrocarbyl-substituted polycarboxylic acid compound comprising at least one quaternizable amino group with a quaternizing agent which converts the at least one quaternizable amino group to a quaternary ammonium group, said quaternizing agent being the alkyl ester of a cycloaromatic or cycloaliphatic mono- or polycarboxylic acid, especially of a mono- or dicarboxylic acid, or of an aliphatic polycarboxylic acid; wherein 1.25 to 2.0 equivalents of quaternizing agent are used per equivalent of quaternizable tertiary nitrogen atom.

2. The fuel composition according to any of the preceding claims, wherein the quaternizing agent is a compound of the general formula 1         R1OC(O)R2     (1) in which R1 is a lower alkyl radical and R2 is an optionally substituted monocyclic aryl or cycloalkyl radical, where the substituent is selected from OH, NH2, NO2, C(O)OR3, and R1OC(O)-, in which R1 is as defined above and R3 is H or R1.

3. The fuel composition according to either of the preceding claims, wherein the quaternizing agent is a compound of the general formula 2         R1OC(O)-A-C(O)OR1a     (2) in which R1 and R1a are each independently a lower alkyl radical and A is hydrocarbylene.

4. The fuel composition according to any of the preceding claims, wherein the quaternized nitrogen compound has a number-average molecular weight in the range from 500 to 5000, 800 to 3000 or 900 to 1500.

5. The fuel composition according to any of the preceding claims, wherein the quaternizing agent is selected from alkyl salicylates, dialkyl phthalates and dialkyl oxalates.

6. The fuel composition according to claim 1, wherein the compound which is reactive, especially capable of addition or condensation, with the polycarboxylic acid and comprises an oxygen or nitrogen group and at least one quaternizable amino group is selected from a) hydroxyalkyl-substituted mono- or polyamines having at least one quaternizable primary, secondary or tertiary amino group; b) straight-chain or branched, cyclic, heterocyclic, aromatic or nonaromatic polyamines having at least one primary or secondary amino group and having at least one quaternizable primary, secondary or tertiary amino group; c) piperazines.

7. The fuel composition according to claim 6, wherein the compound which is reactive, especially capable of addition or condensation, with the polycarboxylic acid and comprises an oxygen or nitrogen group and at least one quaternizable amino group is selected from a) hydroxyalkyl-substituted primary, secondary or tertiary monoamines and hydroxyalkyl-substituted primary, secondary or tertiary diamines, b) straight-chain or branched aliphatic diamines having two primary amino groups; di- or polyamines having at least one primary and at least one secondary amino group; di- or polyamines having at least one primary and at least one tertiary amino group; aromatic carbocyclic diamines having two primary amino groups; aromatic heterocyclic polyamines having two primary amino groups; aromatic or nonaromatic heterocycles having one primary and one tertiary amino group.

8. The fuel composition according to any of the preceding claims, selected from diesel fuels, biodiesel fuels, gasoline fuels and alkanol-containing gasoline fuels.

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