KR20140061425A - Fuel compositions - Google Patents

Abstract

<화학식 B2>

(상기 식에서, R² 및 R³은 1 내지 22개의 탄소 원자를 갖는 동일하거나 상이한 알킬, 알케닐 또는 아릴 기이고; X는 결합 또는 1 내지 20개의 탄소 원자를 갖는 알킬렌 기이고; n은 0 내지 20이고; m은 1 내지 5이고; R⁴는 수소 또는 C₁ 내지 C₂₂ 알킬 기임)
여기서 만니히 반응 생성물 첨가제 (ii)는
(a) 알데히드;
(b) 아민; 및
(c) 치환된 페놀
사이의 만니히 반응의 생성물이고;
여기서 페놀은 200 내지 3000의 분자량을 갖는 1개 이상의 분지형 히드로카르빌 기로 치환된 것인
디젤 연료 조성물.A first additive (i) comprising a quaternary ammonium salt and a second additive (ii) comprising a Mannich reaction product; Wherein the quaternary ammonium salt additive (i) is formed by reaction of a quaternizing agent other than an ester with a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of the formula (B1) or (B2);
&Lt; Formula (B1)

&Lt; Formula (B2)

Wherein R ² and R ³ are the same or different alkyl, alkenyl or aryl groups having 1 to 22 carbon atoms, X is a bond or an alkylene group having 1 to 20 carbon atoms, n is 0 to 20, and; m is 1 to 5; R ⁴ is hydrogen or C ₁ to C ₂₂ alkyl group)
Wherein the Mannich reaction product additive (ii)
(a) aldehyde;
(b) an amine; And
(c) Substituted phenol
&Lt; / RTI > is the product of the Mannich reaction;
Wherein the phenol is substituted with at least one branched hydrocarbyl group having a molecular weight of 200 to 3000
Diesel fuel composition.

Description

[0001] FUEL COMPOSITIONS [0002]

The present invention relates to fuel compositions and additives therefor. In particular, the invention relates to additives for diesel fuel compositions, particularly those suitable for use in modern diesel engines with high pressure fuel systems.

Due to consumer demands and legislation, diesel engines have become much more energy efficient, have improved performance in recent years, and emissions have been reduced.

This improvement in performance and emissions has been caused by improvements in the combustion process. In order to achieve fuel atomization required for such improved combustion, fuel injection equipment using higher injection pressure and reduced fuel injector nozzle hole diameter has been developed. The fuel pressure at the injection nozzle now typically exceeds 1500 bar (1.5 x 10 ⁸ Pa). The work that must be applied to the fuel to achieve this pressure also increases the temperature of the fuel. Such high pressures and temperatures can cause deterioration of the fuel.

Diesel engines with high pressure fuel systems may include, but are not limited to, heavy duty diesel engines and smaller passenger car type diesel engines. Heavy duty diesel engines have very powerful engines, such as the MTU series 4000 diesel with 20 cylinder variants designed primarily for marine use and with power outputs up to 4300 kW, or Renault dXi with 6 cylinders and a power output of about 240 kW 7 &lt; / RTI &gt; A typical passenger car diesel engine is a Peugeot DW10 with four cylinders and a power output of 100 kW or less, depending on the variant.

In all diesel engines related to the present invention, a common feature is the high-pressure fuel system. Typically, pressures in excess of 1350 bar (1.35 x 10 ⁸ Pa) are used, but sometimes up to 2000 bar (2 x 10 ⁸ Pa) or higher pressure may be present.

Two non-limiting examples of such high pressure fuel systems are as follows: a common rail injection system in which fuel is compressed using a high pressure pump and the pump supplies fuel to the fuel injection valve via a common rail; And a unit injection system that combines a high pressure pump and a fuel injection valve into one assembly to achieve the highest possible injection pressure in excess of 2000 bar (2 x 10 ⁸ Pa). In both systems, when the fuel is pressurized, the fuel is often heated to a temperature of about 100 ° C or more.

In a common rail system, the fuel is stored at high pressure in a central accumulator rail or in a separate accumulator before being delivered to the injector. Often, some of the heated fuel returns to the low pressure side of the fuel system, or is returned to the fuel tank. In a unit injection system, the fuel is compressed in the injector to produce a high injection pressure. This again increases the temperature of the fuel.

In both systems, fuel is present in the injector body prior to injection, where it is further heated due to heat from the combustion chamber. The temperature of the fuel at the injector tip may be as high as 250 - 350 ° C.

Thus, the fuel is subjected to stresses of 1350 bar (1.35 x 10 ⁸ Pa) to 2,000 bar (2 x 10 ⁸ Pa) and at a temperature of about 100 ° C to 350 ° C before injection, and sometimes back into the fuel system, Increases the time the fuel undergoes this situation.

A common problem associated with diesel engines is the contamination of the injectors, particularly the injector body and the injector nozzles. Fouling can also occur in the fuel filter. Sprayer nozzle fouling occurs when the nozzle is clogged by deposition from diesel fuel. Fouling of the fuel filter may be associated with the fuel being recycled back to the fuel tank. The deposit is increased by decomposition of the fuel. The deposits may take the form of carbonaceous coke-like residues, or sticky or rubber-like residues. Diesel fuel becomes increasingly unstable as it is heated more, especially when heated under pressure. Thus, diesel engines with high pressure fuel systems can cause increased fuel degradation.

The problem of injector contamination can occur when using any type of diesel engine. However, some fuels may be particularly easy to cause contamination, or fouling may occur more quickly if the fuel is used. For example, fuels containing biodiesel have been found to more easily cause jet fouling. Diesel fuels containing metal species can also cause increased deposits. The metal species may be intentionally added to the fuel in the additive composition, or may be present as a contaminant species. Contamination occurs when metal species from fuel distribution systems, vehicle delivery systems, vehicle fuel systems, other metallic components and lubricants dissolve or disperse in fuel.

In particular, transition metals, especially copper and zinc paper, result in increased deposits. They may typically be present in concentrations from a few ppb (parts per billion) to 50 ppm, but the concentrations which are likely to cause problems are believed to be from 0.1 to 50 ppm, for example from 0.1 to 10 ppm.

If the injector becomes clogged or partially clogged, the release of the fuel becomes less efficient and the mixing of the fuel with the air becomes poor. Over time, this leads to engine power loss, increased exhaust emissions, and poor fuel economy.

As the size of the injector nozzle holes decreases, the relative influence of depositor accumulation becomes more serious. As a simple arithmetic, a layer of 5 μm deposits in a 500 μm hole reduces the flow area by 4%, while a layer of the same 5 μm deposit of 200 μm holes reduces the flow area by 9.8%.

Currently, a nitrogen-containing detergent can be added to diesel fuel to reduce caulking. Typical nitrogen-containing detergents are those formed by the reaction of a polyisobutylene-substituted succinic acid derivative with a polyalkylene polyamine. However, newer engines including finer injector nozzles are more sensitive and current diesel fuel may not be suitable for use in new engines incorporating such smaller nozzle holes.

The inventors have developed a diesel fuel composition that provides improved performance over prior art diesel fuel compositions when used in diesel engines with high pressure fuel systems.

It is advantageous to provide a diesel fuel composition that prevents or reduces the generation of deposits in diesel engines. This fuel composition can be considered to perform a "clean" function, i.e. it prevents or suppresses fouling.

However, it would also be desirable to provide a diesel fuel composition which can also aid in the cleaning of deposits already formed in the engine, particularly deposits formed on the injector, in the engine. This fuel composition, when burned in a diesel engine, removes deposits therefrom and affects the "clean" of the already damaged engine.

As with the "keep clean" property, "cleaning" of a damaged engine can provide significant benefits. For example, good cleaning can lead to increased power and / or increased fuel economy. Also, the removal of deposits from the engine, and particularly from the injector, can increase the time interval before the injector maintenance or replacement is required and thereby reduce the maintenance cost.

The deposits on the injector for the above-mentioned reasons are a problem found especially in modern diesel engines with high pressure fuel systems, but also because the single fuel fed from the pump can be used for all types of engines, It is desirable to provide a diesel fuel composition.

It is also desirable that the fuel composition reduces the fouling of the vehicle fuel filter. It would be useful to provide a composition that prevents or inhibits the generation of fuel filter deposits, i.e., to provide a "clean" It would be useful to provide a composition that removes existing deposits from the fuel filter deposits, i.e., to provide a "clean" function. Compositions that can provide both of these functions would be particularly useful.

It is necessary to consider the effect that the additive may affect the fuel composition as a whole when formulating the fuel additive package. When compounds containing polar and non-polar groups are used as additives, they can sometimes cause problems because they can aid in the mixing of water into the fuel and the formation of emulsions. Water, especially fuels containing a fuel / water emulsion, is undesirable. These can lead to problems such as microbial contamination, corrosion and the like. It is therefore desirable to use additives with a reduced tendency to form emulsions where possible.

According to a first aspect of the present invention, there is provided a process for the preparation of a compound of formula (I), comprising a first additive (i) comprising a quaternary ammonium salt and a second additive (ii) comprising a Mannich reaction product; Wherein the quaternary ammonium salt additive (i) is formed by reaction of a quaternizing agent other than an ester with a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of the formula (B1) or (B2);

&Lt; Formula (B1)

&Lt; Formula (B2)

Wherein R ² and R ³ are the same or different alkyl, alkenyl or aryl groups having 1 to 22 carbon atoms, X is a bond or an alkylene group having 1 to 20 carbon atoms, n is 0 to 20, and; m is 1 to 5; R ⁴ is hydrogen or C ₁ to C ₂₂ alkyl group)

Wherein the Mannich reaction product additive (ii)

(a) aldehyde;

(b) an amine; And

(c) Substituted phenol

&Lt; / RTI &gt; is the product of the Mannich reaction;

Wherein the phenol is substituted with at least one branched hydrocarbyl group having a molecular weight of 200 to 3000

A diesel fuel composition is provided.

The additive compound (i) may be referred to herein as "quaternary ammonium salt additive" or as additive (i).

Additive Compound (ii) may be referred to herein as "Mannich additive" or as additive (ii).

The quaternizing agent used to form the quaternary ammonium salt additive of the present invention is not an ester. By this definition we have found that the compounds of formula RCOOR &lt; ¹ &gt; Is meant to exclude compounds of formula (I) wherein R is an optionally substituted alkyl, alkenyl, aryl, or alkylaryl group and R ¹ is a C ₁ to C ₂₂ alkyl, aryl, or alkylaryl group.

The quaternizing agent is suitably selected from the group consisting of dialkyl sulphates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl substituted epoxides in combination with acids, alkyl halides, alkyl sulphonates, sulphones, hydrocarbyl substituted phosphates , Hydrocarbyl substituted borates, alkyl nitrites, alkyl nitrates, hydroxides, N-oxides or mixtures thereof.

In some embodiments, the quaternary ammonium salt may be prepared from, for example, an alkyl or benzyl halide (especially chloride), followed by an ion exchange reaction to provide various anions as part of the quaternary ammonium salt. Such a process may be suitable for preparing quaternary ammonium hydroxides, alkoxides, nitrites or nitrates.

Preferred quatizers are dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl substituted epoxides in combination with acids, alkyl halides, alkyl sulfonates, sultones, hydrocarbyl substituted phosphates, hydrocarbons Carbyl substituted borates, N-oxides or mixtures thereof.

Suitable dialkyl sulphates for use herein include those including alkyl groups having from 1 to 10, preferably from 1 to 4, carbon atoms in the alkyl chain. A preferred compound is dimethylsulfate.

Suitable benzyl halides include chloride, bromide and iodide. The phenyl group may be optionally substituted, for example, with one or more alkyl or alkenyl groups, especially when chloride is used. A preferred compound is benzyl bromide.

Suitable hydrocarbyl substituted carbonates may include two hydrocarbyl groups which may be the same or different. Each hydrocarbyl group may contain from 1 to 50 carbon atoms, preferably from 1 to 20 carbon atoms, more preferably from 1 to 10 carbon atoms, suitably from 1 to 5 carbon atoms. Preferably, each of the hydrocarbyl group or hydrocarbyl group is an alkyl group. Preferred compounds of this type include diethyl carbonate and dimethyl carbonate.

Suitable hydrocarbyl substituted epoxides have the formula:

Wherein each of R ¹ , R ² , R ³ and R ⁴ is independently hydrogen or a hydrocarbyl group having 1 to 50 carbon atoms. Examples of suitable epoxides include ethylene oxide, propylene oxide, butylene oxide, styrene oxide and stilbene oxide. Hydrocarbyl epoxides are used as quaternizing agents in combination with acids. In the embodiment wherein the hydrocarbyl substituted acylating agent is a dicarboxylic acid acylating agent, no additional acid need be added. However, in other embodiments, an acid such as acetic acid may be used.

Particularly preferred epoxides are propylene oxide and styrene oxide.

Suitable alkyl halides for use herein include chloride, bromide, and iodide.

Suitable alkyl sulfonates include those having 1 to 20, preferably 1 to 10, more preferably 1 to 4 carbon atoms.

Suitable sultones include propanesultone and butanesultone.

Suitable hydrocarbyl substituted phosphates include dialkyl phosphates, trialkyl phosphates and O, O-dialkyl dithiophosphates. Preferred alkyl groups have 1 to 12 carbon atoms.

Suitable hydrocarbyl substituted borate groups include alkyl borates having 1 to 12 carbon atoms.

Preferred alkyl nitrites and alkyl nitrates have from 1 to 12 carbon atoms.

Preferably, the quaternizing agent is selected from dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl substituted epoxides in combination with acids, and mixtures thereof.

Particularly preferred quaternizing agents for use herein are hydrocarbyl substituted epoxides in combination with acids. This includes embodiments where the acid is an additional reactant or is present as part of the structure of the compound where the acid group is quarternized. Preferably, the acid group is present as part of the structure of the quaternized compound.

To form the quaternary ammonium salt additive of the present invention, the quaternizing agent is reacted with a compound formed by the reaction of a hydrocarbyl substituted acylating agent and an amine of formula B1 or B2.

When the compound of formula B1 used for, R ⁴ is preferably hydrogen or C ₁ to C ₁₆ alkyl group, preferably a C ₁ to C ₁₀ alkyl groups, more preferably C ₁ to C ₆ alkyl group. When R &lt; ⁴ &gt; is alkyl, it may be linear or branched. It may be substituted, for example, with a hydroxy or alkoxy substituent. Preferably, R &lt; ⁴ &gt; is not a substituted alkyl group. More preferably, R &lt; ⁴ &gt; is selected from hydrogen, methyl, ethyl, propyl, butyl and isomers thereof. Most preferably, R &lt; ⁴ &gt; is hydrogen.

When the compound of formula (B2) is used, m is preferably 2 or 3, most preferably 2; n is preferably 0 to 15, preferably 0 to 10, more preferably 0 to 5. Most preferably, n is 0 and the compound of formula B2 is an alcohol.

Preferably, the hydrocarbyl substituted acylating agent is reacted with the diamine compound of formula (B1).

R ² and R ³ are the same or different alkyl, alkenyl or aryl groups having 1 to 22 carbon atoms. In some embodiments, R ² and R ³ may be joined together to form a ring structure, such as a piperidine or imidazole moiety. R ² and R ³ may be branched alkyl or alkenyl groups. Each of which may be substituted, for example, with a hydroxy or alkoxy substituent.

R ² and R ³ can each independently be a C ₁ to C ₁₆ alkyl group, preferably C ₁ to C ₁₀ Alkyl group. R ² and R ³ can independently be methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, or the isomer of any of these. Preferably, R ² and R ³ are each independently C ₁ to C ₄ Alkyl. Preferably, R ² is methyl. Preferably, R &lt; ³ &gt; is methyl.

X is a bond or an alkylene group having 1 to 20 carbon atoms. In a preferred embodiment, when X is an alkylene group, the group may be straight-chain or branched. The alkylene group may include a cyclic structure therein. It may be optionally substituted, for example, with a hydroxy or alkoxy substituent.

X preferably has 1 to 16 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, such as 2 to 6 carbon atoms or 2 to 5 carbon atoms Lt; / RTI &gt; Most preferably, X is an ethylene, propylene or butylene group, especially a propylene group.

Examples of suitable compounds of formula (B1) for use herein include 1-aminopiperidine, 1- (2-aminoethyl) piperidine, 1- (1-pyrrolidinyl) piperidine, 1- (2-aminoethyl) pyrrolidine, 2- (2-aminoethyl) -1-methylpyrrolidine , N, N-dimethylethylenediamine, N, N-dibutylethylenediamine, N, N-diethyl-1,3-diaminopropane, N, N'-methylethylenediamine, N, N, N'-tetramethylethylenediamine, N, N, N'-trimethyl-1,3-propanediamine, N, N, 2-dimethylaminopropylamine, 3-diethylaminopropylamine, 3-dibutylaminopropylamine, , 2-tetramethyl-1,3-propanediamine, 2-amino-5-diethylaminopentane, N, N, N ', N'-tetraethyldiethylenetriamine, 3,3'-diamino-N - methyldi (3-aminopropyl) imidazole and 4- (3-aminopropyl) morpholine, 1- (2-aminoethyl) Piperidine, 3,3-diamino-N-methyldipropylamine, 3,3-iminobis (N, N-dimethylpropylamine) or combinations thereof.

In some preferred embodiments, the compound of formula B1 is selected from the group consisting of N, N-dimethyl-1,3-diaminopropane, N, N-diethyl-1,3-diaminopropane, N, N-dimethylethylenediamine, Diethylethylenediamine, N, N-dibutylethylenediamine, or a combination thereof.

Examples of compounds of formula B2 suitable for use herein include triethanolamine, N, N-dimethylaminopropanol, N, N-diethylaminopropanol, N, N-diethylaminobutanol, triisopropanolamine, 1- [ N-dimethyl diethanolamine, N-butyl diethanolamine, N, N-di (diethylamino) But are not limited to, ethanolamine, ethylaminoethanol, N, N-dimethylamino-ethanol, 2-dimethylamino-2-methyl-1-propanol.

In some preferred embodiments, the compound of formula B2 is selected from the group consisting of triisopropanolamine, 1- [2-hydroxyethyl] piperidine, 2- [2- (dimethylamine) ethoxy] Diethylaminoethanol, N, N-dimethylaminoethanol, 2-dimethylamino-2-methyl-1-propanol or a combination thereof.

A particularly preferred compound of formula (B1) is dimethylaminopropylamine.

The amine of formula B1 or B2 reacts with a hydrocarbyl substituted acylating agent. Hydrocarbyl substituted acylating agents may be based on hydrocarbyl substituted mono-, di- or polycarboxylic acids or their reactive equivalents. Preferably, the hydrocarbyl substituted acylating agent is a hydrocarbyl substituted succinic acid compound, such as succinic acid or succinic anhydride.

The hydrocarbyl substituent preferably contains 10 or more, more preferably 12 or more, for example 30 or 50 carbon atoms. Which may contain up to about 200 carbon atoms. Preferably, the hydrocarbyl substituent has a number average molecular weight (Mn) of from 170 to 2800, for example from 250 to 1500, preferably from 500 to 1500, more preferably from 500 to 1100. Mn of 700 to 1300 is particularly preferable.

Hydrocarbyl-based substituents are mono- and di-olefins having 2 to 10 carbon atoms, such as ethylene, propylene, butane-1, isobutene, butadiene, isoprene, 1-hexene, (E. G., Copolymers, terpolymers). &Lt; / RTI &gt; Preferably, these olefins are 1-monoolefins. Hydrocarbyl substituents can also be derived from halogenated (e.g., chlorinated or brominated) analogs of such singly- or interpolymers. Alternatively, the substituent may be replaced with other sources such as monomeric high molecular weight alkenes (e.g., 1-tetra-conten) and its chlorinated analogs and chlorinated analogs, aliphatic petroleum fractions such as paraffin wax and its cracking and chlorination (Eg, poly (ethylene) grease) produced by the Ziegler-Natta process, as well as other sources known to those skilled in the art . Any unsaturation in the substituent can be reduced or eliminated, if desired, by hydrogenation according to procedures known in the art.

As used herein, the term "hydrocarbyl" refers to a group having carbon atoms attached directly to the remainder of the molecule and having predominantly aliphatic hydrocarbon character. Suitable hydrocarbyl groups may contain non-hydrocarbon moieties. For example, it may contain no more than one non-hydrocarbyl group per ten carbon atoms, provided that the non-hydrocarbyl group does not significantly alter the predominant hydrocarbon character of the group. Those skilled in the art will recognize such groups including, for example, hydroxyl, oxygen, halo (especially chloro and fluoro), alkoxyl, alkylmercapto, alkylsulfoxy and the like. Preferred hydrocarbyl-based substituents are purely aliphatic hydrocarbons whose properties are pure and do not contain such groups.

The hydrocarbyl substituents are preferably predominantly saturated, i.e. contain no more than one carbon-to-carbon unsaturated bond per ten carbon-to-carbon single bonds present. Most preferably, it contains no more than one carbon-to-carbon unsaturated bond per 50 carbon-to-carbon bonds present.

A preferred substituent of the hydrocarbyl group is poly- (isobutene) which is known in the art. Thus, in a particularly preferred embodiment, the hydrocarbyl substituted acylating agent is polyisobutenyl substituted succinic anhydride.

The preparation of polyisobutenyl substituted succinic anhydride (PIBSA) is documented in the art. Suitable methods include the thermal reaction of polyisobutene and maleic anhydride (see for example US-A-3,361,673 and US-A-3,018,250), and the reaction of halogenated, especially chlorinated polyisobutene (PIB) with maleic anhydride See for example US-A-3,172,892). Alternatively, the polyisobutenylsuccinic anhydride may be prepared by mixing the polyolefin with maleic anhydride and passing chlorine through the mixture (see, for example, GB-A-949,981).

Conventional polyisobutene and so-called "highly-reactive" polyisobutene are suitable for use in preparing the additive (i) of the present invention. Highly reactive polyisobutene in this connection is defined as polyisobutene wherein the terminal olefinic double bond of at least 50%, preferably at least 70%, is of the vinylidene type as described in EP 0565285. Particularly preferred polyisobutene are those having a terminal vinylidene group in excess of 80 mole% and up to 100 mole%, such as those described in EP1344785.

Other preferred hydrocarbyl groups include those having internal olefins as described, for example, in Applicants' published application WO2007 / 015080.

As used herein, the term &quot; inner olefin &quot; refers to any olefin, i.e., a beta or higher olefin, predominantly containing non-alpha double bonds. Preferably, such materials are substantially fully, for example less than 10% by weight, more preferably less than 5% by weight or less than 2% by weight of alpha or higher olefins. Typical internal olefins include Neodene 1518IO available from Shell.

Internal olefins are sometimes known as isomerized olefins and can be prepared from alpha olefins by isomerization processes known in the art or are available from other sources. The fact that they are also known as internal olefins reflects that they do not necessarily have to be produced by isomerization.

Some preferred acylating agents for use in preparing quaternary ammonium salt additives of the present invention are polyisobutene-substituted succinic acid or succinic anhydride. When the compound of formula (B2) is reacted with a succinic acid acylating agent, the product obtained is a succinic acid ester. If the succinic acid acylating agent, R ⁴ is a reaction with a compound of the formula B1 hydrogen, the product obtained may be a succinimide or succinic amides. When the succinic acid acylating agent is reacted with a compound of formula (B1) in which R &lt; ⁴ &gt; is not hydrogen, the product obtained is an amide.

In a preferred embodiment, the reaction product of the hydrocarbyl-substituted acylating agent and the amine of formula B1 or B2 is an amide or ester.

In a preferred embodiment, the reaction product of the hydrocarbyl-substituted acylating agent and the amine of formula B1 or B2 also has one or more remaining carboxylic acid groups. This can be accomplished by selecting a hydrocarbyl substituted acylating agent having a di or polycarboxylic acid or a reactive equivalent thereof and by selecting a suitable molar ratio of the amine of formula B1 or B2. R ⁴ may be necessary in the case of a polyamide prepared from an amine of formula B2 hydrogen, and to control the reaction conditions in order to avoid already form a de. Such techniques are within the capabilities of one of ordinary skill in the art.

To avoid uncertainty, the succinic acid ester comprises a monoester compound having the formula C1 and a diester compound having the formula C2; Succinimide has the formula C3; The succinamide includes a monoamide compound having the formula C4 and a diamide compound having the formula C5:

In a particularly preferred embodiment, the quaternary ammonium salt additive of the present invention is a salt of a tertiary amine prepared from dimethylaminopropylamine and polyisobutylene-substituted succinic anhydride. The average molecular weight of the polyisobutylene substituent is preferably 700 to 1300, more preferably 900 to 1100.

The quaternary ammonium salt additive of the present invention can be prepared by any suitable method. Such methods will be known to those skilled in the art and are exemplified herein. Typically the quaternary ammonium salt additive is prepared by heating a compound prepared by reaction of a quaternizing agent and a hydrocarbyl substituted acylating agent and an amine of formula B1 or B2 in an approximate 1: 1 molar ratio, optionally in the presence of a solvent . The resulting crude reaction mixture may optionally be added directly to the diesel fuel after removal of the solvent. Residual starting materials that are still present in any by-products or mixtures have not been found to cause any loss in performance of the additive. The present invention thus provides a diesel fuel composition comprising the reaction product of a quaternizing agent with a reaction product of a hydrocarbyl substituted acylating agent and an amine of formula B1 or B2.

A particularly preferred quaternary ammonium salt of the present invention is the reaction product of a polyisobutenyl succinic acid acylating agent and dimethylaminopropylamine (N, N dimethyl 1,3 propanediamine), which forms a semi-amide, Quaternized with oxides.

The composition of the present invention comprises

(a) aldehyde;

(b) an amine; And

(c) a substituted phenol, wherein the phenol is substituted with one or more branched hydrocarbyl groups having a molecular weight of 200 to 3000,

(Ii) which is the product of the Mannich reaction between the first additive and the second additive.

Any aldehyde may be used as the aldehyde component (a) of the Mannich additive. Preferably, the aldehyde component (a) is an aliphatic aldehyde. Preferably, the aldehyde has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms. Most preferably, the aldehyde is formaldehyde.

The amine component (b) of the Mannich additive may be one or more amino or polyamino compounds having at least one NH group. Suitable amino compounds include primary or secondary monoamines having a hydrocarbon substituent of from 1 to 30 carbon atoms or a hydroxyl-substituted hydrocarbon substituent of from 1 to about 30 carbon atoms.

In a preferred embodiment, the amine component (b) is a polyamine.

The polyamine may be selected from any compound comprising two or more amine groups. Preferably, the polyamine is a (poly) alkylene polyamine (which means an alkylene polyamine or a polyalkylene polyamine, in each case including a diamine within the meaning of "polyamine"). Preferably, the polyamine is a (poly) alkylene polyamine having 1 to 6, preferably 1 to 4, most preferably 2 to 3 carbon atoms in the alkylene component. Most preferably, the polyamine is a (poly) ethylene polyamine (i.e., an ethylene polyamine or a polyethylene polyamine).

Preferably, the polyamine has 2 to 15 nitrogen atoms, preferably 2 to 10 nitrogen atoms, more preferably 2 to 8 nitrogen atoms.

Preferably, the polyamine component (b) comprises a moiety R ¹ R ² NCHR ³ CHR ⁴ NR ⁵ R ⁶ wherein each of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is independently Is selected from hydrogen and optionally substituted alkyl, alkenyl, alkynyl, aryl, alkylaryl or arylalkyl substituents.

Thus, the polyamine reactant used to prepare the Mannich reaction product of the present invention preferably comprises an optionally substituted ethylenediamine residue.

Preferably, at least one of R &lt; ¹ &gt; and R &lt; ² &gt; is hydrogen. Preferably, both R &lt; ¹ &gt; and R &lt; ² &gt; are hydrogen.

Preferably, at least two of R ¹ , R ² , R ⁵ and R ⁶ are hydrogen.

Preferably, at least one of R ³ and R ⁴ is hydrogen. In some preferred embodiments, each R &lt; ³ &gt; and R &lt; ⁴ &gt; is hydrogen. In some embodiments, R ³ is hydrogen and R ⁴ is alkyl, such as C ₁ to C ₄ alkyl, especially methyl.

Preferably, at least one of R &lt; ⁵ &gt; and R &lt; ⁶ &gt; is an optionally substituted alkyl, alkenyl, alkynyl, aryl, alkylaryl or arylalkyl substituent.

In embodiments where at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ is not hydrogen, each is independently selected from optionally substituted alkyl, alkenyl, alkynyl, aryl, alkylaryl, or arylalkyl Moiety. Preferably, each is independently selected from hydrogen and optionally substituted C (1-6) alkyl moieties.

In particularly preferred compounds, each of R ¹ , R ² , R ³ , R ⁴ and R ⁵ is hydrogen and R ⁶ is an optionally substituted alkyl, alkenyl, alkynyl, aryl, alkylaryl or arylalkyl substituent. Preferably R ⁶ is optionally substituted C (1-6) alkyl moiety.

The alkyl moiety is hydroxyl, amino (especially unsubstituted amino; -NH-, -NH _2), sulfonyl, sulfoxide, C (1-4) alkoxy, nitro, halo (especially chloro or fluoro) and MER &Lt; / RTI &gt;

The presence of at least one heteroatom such as O, N or S in the alkyl chain can be present to provide an ether, amine or thioether.

A particularly preferred substituent ^{R 1, R 2, R 3} , R 4, R 5 or R ⁶ is a hydroxy -C (1-4) alkyl amino and -C (1-4) alkyl, especially HO-CH ₂ -CH ₂ -, and _{H 2 N-CH 2 -CH 2} - a.

Suitably, the polyamine comprises only amine functional groups or comprises amine and alcohol functional groups.

The polyamines are, for example, ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, hexaethylene heptamine, heptaethylene octamine, propane- Amino-ethylamino) ethanol and N ', N'-bis (2-aminoethyl) ethylenediamine (N (CH ₂ CH ₂ NH ₂ ) ₃ ). Most preferably, the polyamine comprises tetraethylenepentamine or ethylenediamine.

Commercially available sources of polyamines typically contain a mixture of isomers and / or oligomers, and a product made from such a commercially available mixture falling within the scope of the present invention.

The polyamines used to form the Mannich additives of the present invention may be linear or branched and may include cyclic structures.

The phenolic component (c) used to prepare the Mannich additives of the present invention may be substituted with one to four groups (other than phenol OH) on the aromatic ring. For example, it may be a tri- or disubstituted phenol. Most preferably, component (c) is a mono-substituted phenol. The substitution can be in ortho and / or meta and / or para position (s).

Each phenol moiety may be ortho, meta or para substituted with an aldehyde / amine moiety. Compounds in which the aldehyde moiety is ortho or para substituted are most commonly formed. A mixture of compounds may be produced. In a preferred embodiment, the starting phenol is para-substituted, resulting in an ortho-substituted product.

The phenol may be substituted by any common group such as an alkyl group, alkenyl group, alkynyl group, nitrile group, carboxylic acid, ester, ether, alkoxy group, halo group, additional hydroxyl group, mercapto group, An aryl group, an arylalkyl group, a substituted or unsubstituted amine group, or a nitro group.

As mentioned above, the phenol comprises at least one branched hydrocarbyl substituent. The hydrocarbyl substituent may be optionally substituted with, for example, hydroxyl, halo (especially chloro and fluoro), alkoxy, alkyl, mercapto, alkylsulfoxy, aryl or amino moieties. Preferably, the hydrocarbyl group consists essentially of carbon and hydrogen atoms. The substituted phenol may comprise an alkenyl or alkynyl moiety comprising at least one double and / or triple bond.

The hydrocarbyl substituents are preferably predominantly saturated, i.e. contain no more than one carbon-to-carbon unsaturated bond per ten carbon-to-carbon single bonds present. Most preferably, it contains no more than one carbon-to-carbon unsaturated bond per 50 carbon-to-carbon bonds present.

Preferably component (c) is a monoalkylphenol, especially a para-substituted monoalkylphenol, wherein the alkyl chain of the substituent is branched.

In a preferred embodiment, the phenolic component (c) used to prepare the Mannich reaction product additive (ii) comprises a predominantly or fully saturated branched hydrocarbyl substituent. Preferably, the hydrocarbyl substituent, which is predominantly or fully saturated, is branched along the length of the chain. By branching along the length of the chain we mean that there are multiple branches from the main (or longest) chain. Preferably, there is a branching along the main chain for every 10 or more carbon atoms, preferably for every 6 or more carbons, preferably for every 4 or more carbons, for example every 3 carbon atoms or every 2 carbon atoms .

Certain carbon atoms of the main hydrocarbyl chain, which is preferably an alkylene chain, may have one or two branching hydrocarbyl groups. A branched hydrocarbyl group means a hydrocarbyl group that does not form part of the backbone to the present inventors but is attached directly thereto. Thus, the primary hydrocarbyl chain may comprise a moiety -CHR ¹ - or -CR ¹ R ² - wherein R ¹ and R ² are a branched hydrocarbyl group.

Preferably, each branched hydrocarbyl group is an alkyl group, preferably a C ₁ to C ₄ alkyl group, such as, for example, propyl, ethyl or most preferably methyl.

In some preferred embodiments, the phenolic component (c) used to prepare the Mannich reaction product additive (ii) comprises a hydrocarbyl substituent substituted with a methyl group along its main chain. Suitably, there are a number of carbon atoms each having two methyl substituents.

Preferably, the branching points are substantially equally spaced along the backbone of the hydrocarbyl group of the phenolic component (c).

Component (c) used to prepare additive (ii) comprises at least one branched hydrocarbyl substituent. Preferably, it is an alkyl substituent. In a particularly preferred embodiment, the hydrocarbyl substituent is derived from a polyalkene, suitably a polymer of a branched alkene, such as polyisobutene or polypropene.

In a particularly preferred embodiment, component (c) used in the preparation of the Mannich reaction product additive (ii) comprises a poly (isobutene) derived substituent.

Therefore, the Mannich reaction product additive (ii) used in the present invention preferably comprises a hydrocarbyl chain having the following repeating units:

Poly (isobutene) is produced by addition polymerization of isobutene, (CH ₃ ) ₂ C = CH ₂ . Each molecule of the resulting polymer will contain a single alkenes moiety.

Conventional polyisobutene and so-called "highly-reactive" polyisobutene are suitable for use in preparing the additive (ii) of the present invention. Highly reactive polyisobutene in this context is defined as polyisobutene wherein the terminal olefinic double bond of at least 50%, preferably at least 70%, is of the vinylidene type as described in EP 0565285. Particularly preferred polyisobutene are those having a terminal vinylidene group in excess of 80 mole% and up to 100 mole%, such as those described in EP1344785.

Methods for preparing polyalkylene-substituted phenols, such as polyisobutene-substituted phenols, are known to those skilled in the art and include those described in EP 831141.

The hydrocarbyl substituent of component (c) has an average molecular weight of 200 to 3000. Preferably it has a molecular weight of at least 225, suitably at least 250, preferably at least 275, suitably at least 300, such as at least 325 or at least 350. In some embodiments, the hydrocarbyl substituent of component (c) has an average molecular weight of at least 375, preferably at least 400, suitably at least 475, such as at least 500.

In some embodiments, component (c) may comprise a hydrocarbyl substituent having an average molecular weight of 2800 or less, preferably 2600 or less, such as 2500 or less or 2400 or less.

In some embodiments, the hydrocarbyl substituent of component (c) has an average molecular weight of 400 to 2500, such as 450 to 2400, preferably 500 to 1500, suitably 550 to 1300.

In some embodiments, the hydrocarbyl substituent of component (c) has an average molecular weight of 200 to 600.

In some embodiments, the hydrocarbyl substituent of component (c) has an average molecular weight of 500 to 1000.

In some embodiments, the hydrocarbyl substituent of component (c) has an average molecular weight of 700 to 1300.

In some embodiments, the hydrocarbyl substituent of component (c) has an average molecular weight of from 1000 to 2000.

In some embodiments, the hydrocarbyl substituent of component (c) has an average molecular weight of from 1700 to 2600, for example from 2000 to 2500.

Unless otherwise stated, all of the average molecular weights referred to herein are number average molecular weights.

The components (a), (b) and (c) used to prepare the Mannich product additive (ii) may each comprise a mixture of compounds and / or a mixture of isomers.

(B) and (c) in a molar ratio of preferably from 5: 1: 5 to 0.1: 1: 0.1, more preferably from 3: 1: 3 to 0.5: 1: Is a reaction product obtained by reaction.

To form the Mannich additive of the present invention, components (a) and (b) are preferably used in a ratio of from 6: 1 to 1: 4 (aldehyde: amine), preferably from 4: 1 to 1: Reacts at a molar ratio of 3: 1 to 1: 1.

In a preferred embodiment, the molar ratio of component (a) to component (b) (aldehyde: amine) in the reaction mixture is preferably greater than 1: 1, preferably greater than or equal to 1.1: 1, more preferably greater than or equal to 1.3: Suitably at least 1.5: 1, for example at least 1.6: 1.

Preferably, the molar ratio of component (a) to component (b) (aldehyde: amine) in the reaction mixture is less than 3: 1, preferably 2.7: 1 or less, more preferably 2.3: 1 or less, : 1 or less or 2: 1 or less.

Preferably, the molar ratio of component (a) to component (b) (aldehyde: amine) in the reaction mixture used to prepare the Mannich additives of the present invention is from 1.1: 1 to 2.9: 1, preferably from 1.3: Is preferably from 2.7: 1, preferably from 1.4: 1 to 2.5: 1, more preferably from 1.5: 1 to 2.3: 1 and preferably from 1.6: 1 to 2.2: 1, for example from 1.7: 1 to 2.1: 1.

In order to form the preferred Mannich additives of the present invention, the molar ratio of component (a) to component (c) (aldehyde: phenol) in the reaction mixture is preferably from 5: 1 to 1: 4, preferably from 3: 1: 2, for example from 2: 1 to 1: 1.

In a preferred embodiment, the molar ratio of component (a) to component (c) (aldehyde: phenol) in the reaction mixture used to prepare the Mannich additives of the present invention is greater than 1: 1; Preferably 1.1: 1 or more; Preferably 1.2: 1 or more, more preferably 1.3: 1 or more.

Preferably, the molar ratio of component (a) to component (c) (aldehyde: phenol) is less than 2: 1, preferably 1.9: 1 or less; More preferably 1.8: 1 or less, for example, 1.7: 1 or less; More preferably 1.6: 1 or less.

Suitably, the molar ratio of component (a) to component (c) (aldehyde: phenol) in the reaction mixture used to prepare the Mannich additive is from 1.05: 1 to 1.95: 1, preferably from 1.1: 1 to 1.85: , More preferably 1.2: 1 to 1.75: 1, suitably 1.25: 1 to 1.65: 1, and most preferably 1.3: 1 to 1.55: 1.

To form the Mannich additive of the present invention, components (c) and (b) are preferably used in a ratio of from 6: 1 to 1: 4 (phenol: amine), preferably from 4: 1 to 1: Reacts at a molar ratio of from 3: 1 to 1: 2, more preferably from 2: 1 to 1: 2.

Suitably, the molar ratio of component (c) to component (b) (phenol: amine) in the reaction mixture is from 0.7: 1 to 1.9: 1, preferably from 0.8: 1 to 1.8: 1, 1 to 1.4: 1, preferably from 1: 1 to 1.6: 1, preferably from 1.1: 1 to 1.5: 1, and preferably from 1.2: 1 to 1.4: 1.

In a preferred embodiment, the molar ratio of component (c) to component (b) (phenol: amine) in the reaction mixture is greater than 0.5: 1; Preferably 0.8: 1 or more; Preferably not less than 0.9: 1, more preferably not less than 1: 1, for example, not less than 1.1: 1.

Preferably, the molar ratio of component (c) to component (b) (phenol: amine) in the reaction mixture is less than 2: 1, preferably 1.9: 1 or less; More preferably 1.7: 1 or less, for example, 1.6: 1 or less; More preferably 1.5: 1 or less.

In some preferred embodiments, the molar ratio of component (a) to component (b) in the Mannich reaction used to form the additive is 2.2-1.01: 1; The molar ratio of component (a) to component (c) is 1.99-1.01: 1 and the molar ratio of component (b) to component (c) is 1: 1.01-1.99.

In some preferred embodiments, the molar ratio of component (a) to component (b) in the reaction used to prepare the Mannich additive is 2-1.6: 1 and the molar ratio of component (a) : 1, and the molar ratio of component (b) to component (c) is 1: 1.1-1.5.

Some preferred compounds used in the present invention are typically 1.8 parts (a) ± 0.3 parts (a), 1 part (b), 1.3 parts (c) ± 0.3 parts (c); Preferably, 1.8 parts (a) ± 0.1 parts (a), 1 part (b), 1.3 parts (c) ± 0.1 parts (c); (A), (b) and (c), preferably in a molar ratio of about 1.8: 1: 1.3 (a: b: c).

The suitable throughput rates of the quaternary ammonium salt additive and the Mannich additive, if any, will vary depending upon the desired performance and the type of engine in which they are used. For example, various levels of additives may be required to achieve varying levels of performance.

Suitably, the quaternary ammonium salt additive is present in an amount of from 1 to 10,000 ppm, preferably from 1 to 1000 ppm, more preferably from 5 to 500 ppm, suitably from 5 to 250 ppm, such as from 5 to 150 ppm, Is present in the composition.

Suitably, when used, the niacy additive is present in an amount of 1 to 10,000 ppm, preferably 1 to 1000 ppm, more preferably 5 to 500 ppm, suitably 5 to 250 ppm, for example 5 to 150 ppm Diesel fuel composition.

The weight ratio of the quaternary ammonium salt additive to the Mannich additive is preferably from 1:10 to 10: 1, preferably from 1: 4 to 4: 1, for example from 1: 3 to 3: 1.

As mentioned above, fuels containing biodiesel or metals are known to cause fouling. Those that contain stringent fuels, such as high levels of metals and / or high levels of biodiesel, may require quarternary ammonium salt additives and / or Mannich additives at higher throughput than less stringent fuels.

The diesel fuel composition of the present invention may comprise one or more additional additives such as those conventionally found in diesel fuel. This may be achieved, for example, by the addition of an antioxidant, a dispersant, a detergent, a metal deactivating compound, an anti-waxing agent, a low temperature flow improver, a cetane number improver, a demulsifier, a stabilizer, a demulsifier, a defoamer, Improvers, metal deactivators, odor blockers, drag reducers, and conductivity improvers. Examples of suitable amounts of each of these types of additives will be known to those skilled in the art.

In some preferred embodiments, the composition further comprises a demulsifier / demulsifier.

De-emulsifiers / demulsifiers are commercially available, for example, from Nalco or Baker Hughes. Suitable compounds include, but are not limited to, alkoxylated phenol formaldehyde polymers, alkylated phenols and resins derived therefrom, oxylated alkyl phenol based resins, polyglycol esters, epoxides such as diepoxides, polyols, polyamines, and ethylene oxide / propylene oxide block copolymers But are not limited to. Particularly preferred de-emulsifiers / de-smoke removers are mixtures of 2-4 different components comprising at least one alkoxylated phenol formaldehyde.

The demulsifier / demulsifier is suitably present in an amount of 0.01 to 1000 ppm, preferably 0.1 to 500 ppm, more preferably 0.5 to 100 ppm, for example 1 to 50 ppm.

In some preferred embodiments, the composition further comprises a defoamer additive. Suitable defoamer additives are well known to those skilled in the art and include, for example, organically modified siloxanes, organically modified polydimethylsiloxanes, or polysiloxane polyether copolymers. Examples of such compounds are available under the trademark SAG ™ TP-317 or TP-325 or Dow Corning® 2-2617 from Momentive Perfomance Materials.

The defoamer additives are suitably present in an amount of from 0.01 to 1000 ppm, preferably from 0.1 to 500 ppm, more preferably from 0.5 to 100 ppm, for example from 1 to 50 ppm.

In some preferred embodiments, the composition further comprises a detergent of the type formed by the reaction of a polyisobutene-substituted succinic acid-derived acylating agent and a polyethylene polyamine. Suitable compounds are described, for example, in WO2009 / 040583.

By diesel fuel, the inventors include any fuel suitable for use in diesel engines for road use or non-road use. This includes, but is not limited to, fuels described as diesel, marine diesel, heavy fuel oil, industrial fuel oil, and the like.

The diesel fuel composition of the present invention may comprise a petroleum-based fuel oil, especially a mid-distillate fuel oil. Such distillate fuel oil generally boils within a range of 110 ° C to 500 ° C, for example, 150 ° C to 400 ° C. The diesel fuel may comprise a blend of any proportion of the direct and refinery streams such as atmospheric distillates or vacuum distillates, cracked gas oil, or thermally and / or catalytically cracked and hydro-cracked distillates. have.

The diesel fuel composition of the present invention may comprise Fischer-Tropsch fuels. This may include non-renewable Fischer-Tropsch fuels, such as those described as GTL (gas-liquefied) fuels, CTL (coal-liquefied) fuels and OTL (oil sand-liquefied).

The diesel fuel composition of the present invention may comprise a renewable fuel, such as a biofuel composition or a biodiesel composition.

The diesel fuel composition may comprise a first generation biodiesel. First generation biodiesel contains, for example, vegetable oils, animal fats and esters of cooking fats used. This type of biodiesel can be used in the presence of a catalyst such as oils such as rapeseed oil, soybean oil, safflower oil, palm oil 25, corn oil, peanut oil, cottonseed oil, tallow, coconut oil, Jatropha), sunflower seed oil, cooking oil used, hydrogenated vegetable oil or any mixture thereof and an alcohol, typically a monoalcohol.

The diesel fuel composition may comprise a second generation biodiesel. Second generation biodiesel is derived from renewable sources such as vegetable oils and animal fats and is often processed at refineries using hydrogenation processes such as the H-bio process, often developed by Petrobras. Second generation biodiesel can be similar in character and quality to petroleum-based fuel oil streams and can be produced, for example, from vegetable oils, animal fats, and the like, and used as a renewable diesel by ConocoPhillips , And NexBTL by Neste.

The diesel fuel composition of the present invention may comprise a third generation biodiesel. Third generation biodiesel uses gasification and Fischer-Tropsch techniques, including those described as BTL (biomass-liquefied) fuels. The third generation biodiesel is not significantly different from some second-generation biodiesel, but aims to expand the feedstock base by utilizing the entire plant (biomass).

The diesel fuel composition may contain a blend of any or all of the diesel fuel compositions.

In some preferred embodiments, the diesel fuel composition comprises Fischer-Tropsch fuel and / or biodiesel.

In some embodiments, the diesel fuel composition of the present invention may be a blended diesel fuel comprising bio-diesel. In such a blend, the bio-diesel may contain, for example, up to 0.5%, up to 1%, up to 2%, up to 3%, up to 4%, up to 5%, up to 10%, up to 20% Or less, 50% or less, 60% or less, 70% or less, 80% or less, 90% or less, 95% or less or 99% or less.

In some preferred embodiments, the composition comprises 1 to 20% by weight, preferably 5 to 10% by weight of biodiesel.

In some embodiments, the diesel fuel composition may comprise a secondary fuel, e. G. Ethanol. Preferably, however, the diesel fuel composition does not contain ethanol.

The diesel fuel composition of the present invention may contain a relatively high sulfur content, for example greater than 0.05% by weight, such as 0.1% by weight or 0.2% by weight.

However, in a preferred embodiment, the diesel fuel has a sulfur content of less than 0.05 wt%, more preferably less than 0.035 wt%, especially less than 0.015 wt%. Fuel having even lower sulfur levels, such as fuels having less than 50 weight ppm sulfur, preferably less than 20 weight ppm sulfur, such as less than 10 weight ppm sulfur, is also suitable.

If present, the metal-containing species will be present as a contaminant through corrosion of metal and metal oxide surfaces, for example, in fuel or by acid species derived from lubricants. In use, fuels such as diesel fuel routinely come into contact with metal surfaces such as, for example, vehicle fuel supply systems, fuel tanks, fuel transporters, and the like. Typically, metal-containing contaminants include transition metals such as zinc, iron and copper; Group I or Group II metals such as sodium; And other metals such as lead.

In addition to the metal-containing contamination that may be present in diesel fuel, there are situations in which the metal-containing species can be intentionally added to the fuel. As known in the art, for example, metal-containing fuel-bearing catalyst papers may be added to aid in regeneration of the particulate trap. Such catalysts are often based on metals such as iron, cerium, Group I and Group II metals, such as calcium and strontium, as a mixture or alone. Platinum and manganese are also used. The presence of such catalysts may cause injector deposits when fuel is used in diesel engines with high pressure fuel systems.

The metal-containing contamination may be in the form of insoluble particulate or soluble compounds or complexes depending on the source thereof. Metal-containing fuel-embedded catalysts are often soluble compounds or complexes or colloidal species.

In some embodiments, the metal-containing species comprises a fuel-embedded catalyst.

In some embodiments, the metal-containing species comprises zinc.

In one preferred embodiment, the diesel fuel composition of the present invention comprises a fuel-bearing catalyst comprising a metal selected from iron, cerium, Group I and Group II metals, platinum, manganese, and mixtures thereof. Preferred Group I and Group II metals include calcium and strontium.

Typically, the amount of metal-containing species in the diesel fuel is from 0.1 to 50 ppm by weight, for example from 0.1 to 10 ppm by weight, based on the weight of the diesel fuel, expressed in terms of the total weight of the metals in the species.

The fuel compositions of the present invention exhibit improved performance when used in diesel engines with high pressure fuel systems as compared to prior art diesel fuels.

According to a second aspect of the present invention there is provided an additive package that provides the composition of the first aspect upon addition to the diesel fuel.

The additive package may include a quaternary ammonium salt additive, Mannich additive and optionally further additives, such as a mixture of those described above. Alternatively, the additive package may comprise a solution of the additive, suitably a hydrocarbon solvent, such as an aliphatic and / or aromatic solvent; And / or an oxidizing solvent, for example, a mixture of an alcohol and / or an ether.

According to a third aspect of the present invention, there is provided a method of operating a diesel engine, comprising combusting the composition of the first aspect in the engine.

According to a fourth aspect of the present invention there is provided a process for the preparation of a quaternary ammonium salt additive (i) and a Mannich reaction product additive (ii) in the diesel fuel composition for improving the engine performance of a diesel engine when using the diesel fuel composition Uses are provided.

Preferred features of the second, third and fourth aspects are as defined in relation to the first aspect.

Improved performance can be achieved by reducing or preventing the formation of deposits in the diesel engine. This can be regarded as an improvement in "cleanliness" performance. Accordingly, the present invention can provide a method for reducing or preventing the formation of deposits in a diesel engine by burning the composition of the first aspect in the engine.

Improved performance can be achieved by removing existing deposits in the diesel engine. This can be regarded as an improvement in "cleaning" performance. Thus, the present invention can provide a method for removing deposits from a diesel engine by burning the composition of the first aspect in the engine.

In a particularly preferred embodiment, the composition of the first aspect of the present invention can be used to provide "cleanliness" and "cleaning" performance improvements.

In some preferred embodiments, the use of the third aspect relates to a method for improving the engine performance of a diesel engine having a high-pressure fuel system when using a diesel fuel composition, in a diesel fuel composition, optionally in combination with an additive, Lt; RTI ID = 0.0 &gt; ammonium salt &lt; / RTI &gt;

Modern diesel engines with high-pressure fuel systems can be characterized in a number of ways. Such an engine is typically equipped with a fuel injector having a plurality of openings, each opening having an inlet and an outlet.

This state-of-the-art diesel engine can feature point-like openings such that the inlet diameter of the spray-holes is greater than the outlet diameter.

These modern engines may feature openings having an outlet diameter of less than 500 mu m, preferably less than 200 mu m, more preferably less than 150 mu m, preferably less than 100 mu m, most preferably less than 80 mu m, or less.

This latest diesel engine can feature openings with curved internal corners of the inlet.

Such a state-of-the-art diesel engine may be characterized by an injector having more than one opening, suitably more than two openings, preferably more than four openings, for example six or more openings.

These modern diesel engines can feature operating tip temperatures in excess of 250 ° C.

These modern diesel engines may feature fuel pressures in excess of 1350 bar, preferably in excess of 1500 bar, and more preferably in excess of 2000 bar.

The use of the present invention preferably improves the performance of an engine having at least one of the characteristics described above.

The present invention is particularly useful for preventing or reducing or eliminating deposits on the injector of an engine that operate at high pressures and temperatures and in which the fuel can be recycled and the fuel is passed through the engine to the engine. The present invention finds utility in engines for heavy vehicles and passenger vehicles. For example, a passenger vehicle incorporating a high-speed direct injection (or HSDI) engine can benefit from the present invention.

Within the injector body of modern diesel engines with high-pressure fuel systems there has been a report of engine problems in the field where a clearance of only 1-2 [mu] m may exist between the actuators and caused by injector fixation, particularly injector open fixation . Control of deposits in this area can be very important.

The diesel fuel composition of the present invention can also provide improved performance when used in conjunction with conventional diesel engines. Preferably, the improved performance is achieved when using diesel fuel compositions in modern diesel engines with high pressure fuel systems and when using the compositions in conventional diesel engines. This is important because it enables the delivery of a single fuel that can be used in new engines and older vehicles.

Improvements in the performance of a diesel engine system can be measured by a number of methods. A suitable method will vary depending on the type of engine and whether "clean" and / or "clean" performance is measured.

One way to measure improvement in performance is to measure power loss in controlled engine tests. Improvement in "cleanliness" performance can be measured by observing a reduction in power loss compared to that seen in base fuel. "Cleaning" performance can be observed by increasing the power when the diesel fuel composition of the present invention is used in an engine that has already been damaged.

Improved performance of diesel engines with high pressure fuel systems can be measured by improved fuel economy.

The use of the third aspect can also improve the performance of the engine by reducing, preventing or eliminating deposits in the vehicle fuel filter.

The level of deposits in a vehicle fuel filter can be measured quantitatively or qualitatively. In some cases, this can only be measured by checking the filter if the filter is removed. In other cases, the level of deposit may be estimated during use.

A number of vehicles are equipped with fuel filters that can be visually inspected during use to measure the level of solids accumulation and the need for filter replacement. For example, such a system uses a filter canister in a transparent housing that enables the filter, the fuel level in the filter, and the degree of filter clogging to be observed.

The use of the fuel composition of the present invention can result in a level of deposit in the fuel filter that is significantly reduced compared to the fuel composition that is not the present invention. This allows the filter to be replaced much less frequently and ensures that the fuel filter does not fail between service intervals. Thus, the use of the compositions of the present invention can lead to reduced maintenance costs.

In some embodiments, the generation of deposits in the fuel filter can be suppressed or reduced. Thus "cleanliness" performance can be observed. In some embodiments, existing deposits may be removed from the fuel filter. Thus, "cleaning" performance can be observed.

Improvement in performance can also be evaluated in view of the extent to which the use of the fuel composition of the present invention reduces the amount of deposits on the injector of the engine. For "clean" performance, a reduction in the occurrence of sediment will be observed. For "cleaning ", performance removal of existing sediment will be observed.

Direct measurement of deposit accumulation is not typically undertaken, but is typically estimated from power loss or fuel flow through the injector.

The use of the third aspect can improve engine performance by reducing, preventing or eliminating deposits, including gums and lacquers, in the injector body.

In Europe, the European Community Council (an industry body known as the CEC) for the development of performance tests for transport fuels, lubricants and other fluids satisfies the new European Union emission legislation known as the "Euro 5" To evaluate whether diesel fuel is suitable for use in an engine, a new test named CEC F-98-08 was developed. The test is based on a Peugeot DW10 engine using a Euro 5 injector and will hereinafter be referred to as the DW10 test. This will be further described with reference to the embodiment (see Example 9).

Preferably the use of the fuel composition of the present invention leads to a reduced deposit in the DW10 test. For "clean" performance, a reduction in the occurrence of sediment is preferably observed. For "cleaning" performance, removal of the precipitate is preferably observed. The DW10 test is used to measure the power loss of modern diesel engines with high-pressure fuel systems.

In the case of older engines, the improvement in performance can be measured using the XUD9 test. This test is described in connection with the tenth embodiment.

Suitably, the use of the fuel composition of the present invention may provide "clean" performance in modern diesel engines, i.e. the formation of deposits on the injectors of such engines will be suppressed or prevented. Preferably, this performance allows a power loss of less than 5%, preferably less than 2%, to be observed after 32 hours as measured by the DW10 test.

Suitably, the use of the fuel composition of the present invention can provide "cleaning" performance in modern diesel engines, i.e., deposits can be removed on the injectors of an already damaged engine. Preferably, this performance allows the power of the damaged engine to return to within 1% of the level achieved when using a clean injector within 32 hours as measured by the DW10 test.

Preferably, the power is within 1% of the level observed when using a clean jet within 10 hours, preferably within 8 hours, preferably within 6 hours, preferably within 4 hours, more preferably within 2 hours A quick "cleaning" can be achieved.

A clean injector may include a new injector or, for example, an injector that is removed and physically cleaned in an ultrasonic bath.

Suitably, the use of the fuel composition of the present invention can provide "clean" performance in conventional diesel engines, i.e. formation of deposits on the injectors of such engines can be suppressed or prevented. Preferably, this performance allows a flow loss of less than 50%, preferably less than 30%, to be observed after 10 hours as measured by the XUD-9 test.

Suitably, the use of the fuel composition of the present invention can provide "cleaning" performance in conventional diesel engines, i.e., deposits on the injector of an already damaged engine can be removed. Preferably, this capability allows the flow loss of the damaged engine to increase by more than 10% within 10 hours measured by the XUD-9 test.

The compositions of the present invention, as well as achieving improvements in the performance of diesel engines as described herein, have also been found to be stable upon storage.

In particular, the compositions of the present invention have been found to have a reduced tendency towards the formation of emulsions as compared to similar compositions of the prior art.

According to a fifth aspect of the present invention there is provided a process for the preparation of a diesel fuel composition which comprises a first additive (i) comprising a quaternary ammonium salt as defined in relation to the first aspect for inhibiting the formation of an emulsion in a diesel fuel composition and a Mannich reaction product (Ii) is provided.

By inhibiting the formation of an emulsion, we mean that the emulsion is less easily formed and / or more easily separated than when similar engine performance additives of the prior art are used.

The present invention relates to a Mannich reaction product (ii) as defined herein for improving the demulsifying performance of a diesel fuel composition comprising a demulsifier / demulsifier and a quaternary ammonium salt additive (i) as defined herein, Lt; / RTI &gt;

The tendency of water and fuel to be separated rather than forming an emulsion can be measured using the standard test method ASTM D7451 described in Example 8. [

In this test, the fuel and water are shaken under the prescribed conditions, and the time required for separating the fuel water and the quality of the separation are evaluated.

The time it takes for fuel and water to separate during mixing is particularly important in that it ensures the quality of the fuel taken from the storage tank. When a new fuel is added to the storage tank, if any emulsified fuel / water is present, it will not be allowed to supply the fuel to the end user until the fuel and water are separated. Similarly, fuel transparency should be allowed to the end user.

Interfacial conditions and fuel water separation grades are particularly important to ensure that microbial growth is minimized at the fuel / water interface.

This test is a common requirement for fuel companies when evaluating fuel additive performance.

Any feature of any aspect of the invention may be combined with any other feature as appropriate.

The invention will now be further defined with reference to the following non-limiting examples.

Example 1

Additive A, a quaternary ammonium salt additive of the present invention was prepared as follows:

A mixture of succinic anhydride prepared from 1000 Mn polyisobutylene (21425 g) and dilute oil-pilot 900 (3781 g) was heated with stirring at 110 DEG C under a nitrogen atmosphere. Dimethylaminopropylamine (DMAPA, 2314 g) was slowly added over 45 minutes maintaining the batch temperature below 115 &lt; 0 &gt; C. The reaction temperature was increased to 150 &lt; 0 &gt; C and held for an additional 3 hours. The resulting compound was DMAPA succinimide.

The DMAPA succinimide was heated with styrene oxide (12.5 g), acetic acid (6.25 g) and methanol (43.4 g) under reflux (about 80 ° C) with stirring for 5 hours under a nitrogen atmosphere. The mixture was purified by distillation (30 DEG C, -1 bar) to give the styrene oxide quaternary ammonium salt as a colorless transparent distillate.

Example 2 (comparative)

Additive B, the Mannich reaction product of the prior art, was prepared as follows:

The reactor was charged with dodecylphenol (170.6 g, 0.65 mol), ethylenediamine (30.1 g, 0.5 mol) and Caromax 20 (123.9 g). The mixture was heated to 95 DEG C and a formaldehyde solution, 37 wt% (73.8 g, 0.9 mol), was charged over 1 hour. The temperature was increased to 125 &lt; 0 &gt; C for 3 hours and water was removed. In this Example, the molar ratio of aldehyde (a): amine (b): phenol (c) was approximately 1.8: 1: 1.3.

Example 3

Polyisobutene-substituted phenol was prepared as follows:

Polyisobutene (450.3 g, 0.53 mol, 1 eq.) Having an average molecular weight of 750 was heated to 45-50 占 and phenol (150.0 g, 1.59 mol, 3 eq.) Was then added. The mixture was stirred and boron trifluoride diethate (15.0 g, 0.10 mol, 0.18 eq.) Was added in 2-3 ml aliquots over approximately 2 hours to give a clear orange liquid which was chromatographed on a 45- Stir at 50 &lt; 0 &gt; C. Then 35% aqueous ammonia (10.5 g, 0.22 mol) was added and the reaction mixture was stirred for 30 minutes. Vacuum distillation provided 81.3 g of distillate. This was stirred in toluene (250.3 g) at 70 &lt; 0 &gt; C for 5 minutes, then 250.4 g of water were added. The layers were separated and the toluene extract was washed twice more with water. The residue and toluene were removed in vacuo to provide the product as a viscous light yellow liquid (510.9 g) having a toluene content of 2% by weight and a phenol content of less than 0.2% by weight.

Example 4

Additive C, the Mannich additive of the present invention was prepared as follows:

PIB 750 phenol (phenol with a polyisobutenyl substituent having an average molecular weight of 750) having a residual PIB content of 5 wt.% (447.8 g, 425.4 g "active" PIB phenol, 0.50 mol, 1.3 eq.) Was mixed with ethylenediamine (25.3 g, 0.38 mol, 1 eq.) And Carromax 20 solvent (225.6 g). The homogeneous mixture was heated to 90-95 占 폚. Then 36.7% formalin (57.12 g, 0.69 mol, 1.8 eq.) Was added over 1 hour, then the reaction mixture was maintained at 95 캜 for 1 hour. The water was removed using a Dean-Stark apparatus. 708.3 g of product was collected after distillation.

Example 5

Three diesel additive formulations were prepared according to Table 1.

<Table 1>

De-emulsifiers (1) Commercially available de-emulsifiers / de-dusting agents comprising a mixture of phenolic resins in an aromatic solvent.

Defoamers; (2) commercially available defoamer additives including organo-modified siloxanes in aromatic solvents.

Solvents (3) Commercially available blends of aromatic and aliphatic solvents

Example 6

The diesel fuel compositions were prepared by adding the additive compositions listed in Table 1 to all of the aliquots taken from the common arrangement of the RF06 base fuel and containing 1 ppm zinc (as zinc neodecanoate). A total additive throughput of 350 ppm was used in each case.

Table 2 below shows the specifications of the RF06 base fuel.

<Table 2>

Example 7

Diesel fuel composition added to all of the aliquots taken from a common batch of B7 reference fuels made from 7% biodiesel containing 93% RF06 base fuel and rapeseed oil methyl ester, including the additive compositions listed in Table 1 . Again, a total additive throughput of 350 ppm was used.

Example 8

The fuel compositions prepared in Examples 6 and 7 were mixed with modified versions of ASTM D7451 (light and medium distillates, and Water Separation Properties of Light and Middle Distillate, and Compression and Spark Ignition Fuels) ). &Lt; / RTI &gt;

This test is designed to evaluate the tendency of water and fuel to be separated rather than forming emulsions when they contain potential emulsion-forming additives or ingredients. In this test, 80 ml of fuel and 20 ml of water were shaken together under controlled conditions and allowed to stand for a predetermined period of time. After 5 minutes, the volume of the aqueous layer, fuel transparency, fuel water separation and interface conditions were evaluated according to standard specifications.

Except that the test was carried out according to ASTM D7451-08:

6.1) A 100 ml measuring cylinder with a stopper as specified in ASTM D1094 was used instead of the tube specified in D7451.

10.1) The aqueous phase was first added to the tube rather than the fuel.

11.1) Time spent to reach 20 ml clear water was also recorded.

NOTE: The numbered section refers to the numbering section of the D7451 test method.

This test is a common requirement for fuel companies when evaluating fuel additive performance.

The results of the ASTM D 7451 test on the two fuels are provided in Tables 3 to 6.

In this test, the time required for the 20 ml water to return and the volume of the aqueous layer at 5 minutes each provide an indication of how fast the fuel / water emulsion will be separated again into two distinct phases. Both interfacial state grades, fuel transparency grades, and fuel-water separation grades provide an indication of how well separation is taking place.

The results of the double ASTM D7451 test of the fuel composition of Example 6 using an aqueous phase at pH 4, pH 7 and pH 9 are provided in Tables 3-5.

The results of the double ASTM D7451 test of the fuel composition of Example 7 using an aqueous phase at pH 4 are provided in Table 6.

<Table 3>

<Table 4>

<Table 5>

<Table 6>

In this test, the fuel transparency and the fuel-water separation grade after 5 minutes were quite similar. However, Composition 3 provided significantly better performance than Composition 1 or 2, as evidenced by the volume of the aqueous layer after 5 minutes, the interface state grade, and the time it takes for 20 ml of water to return.

Example 9

The performance of the diesel fuel composition of the present invention in modern diesel engines can be tested according to the CECF-98-08 DW 10 method.

The engine of the injector pollution test was PSA DW 10BTED4. In summary, the engine characteristics are as follows:

Design: Turbocharged with 4 cylinders in series, overhead camshaft, EGR

Capacity: 1998 cm ³

Combustion chamber: four valves, bowl-in-piston, wall-induced direct injection

Power: 100 kW at 4000 rpm

Torque: 320 Nm at 2000 rpm

Injection system: Common rail with piezo electronically controlled 6-hole injector

Maximum pressure: 1600 bar (1.6 x 10 ⁸ Pa). Exclusive design by Siemens VDO

Emission control: Meets the Euro IV limit when combined with the exhaust aftertreatment system (DPF).

These engines have been selected as a representative design for the latest European high-speed direct injection diesel engines that can meet current and future European emissions requirements. The common rail injection system uses a highly efficient nozzle design with circular inlet edges and conical spray holes for optimal hydraulic flow. This type of nozzle has made it possible to achieve improvements in combustion efficiency, reduced noise and reduced fuel consumption when combined with high fuel pressures, but it is possible to disturb the fuel flow, such as formation of deposits in spray holes It is sensitive to the effects it has. The presence of these deposits results in a significant loss of engine power and increased unreacted material emissions.

The test was performed using a representative future injector design of the expected Euro V injector technology.

Since it is considered necessary to establish a reliable criterion of the injector conditions prior to the start of the fouling test, a non-fouling reference fuel was used to schedule a 16 hour tame for the test injector.

The full specification for the CEC F-98-08 test method is available from CEC. The caulking cycle is summarized below.

1. Warm-up period according to the following regime (12 minutes):

2. 8 hours of engine operation consisting of 8 repetitions of the following cycle

3. Cooling for idling within 60 seconds and idling for 10 seconds

4. 4 hour soak period

The standard CEC F-98-08 test method consists of a total of 56 hours of test time excluding 32 hours of engine operation corresponding to four repeats of steps 1-3 above and three repeats of step 4, i.e., warm-up and cooling do.

In each case, the first 32 hour period was driven using a new injector and RF-06 base fuel with 1 ppm Zn (as neodecanoate) added. This caused a certain level of power loss due to the fouling of the injector.

The second 32-hour period can then be driven as a 'clean' step. The dirty injectors from the first stage were kept in fuel replaced with the engine and RF-06 base fuel to which 1ppm Zn (as neodecanoate) and test additive had been added.

Example 10

The effectiveness of the additives of the present invention in older engine types can be evaluated using standard industry test-CEC Test Method No. CEC F-23-A-01.

This test uses a Peugeot XUD9 A / L engine to measure injector nozzle cocking and provides a means to distinguish between different injector nozzle caulking tendencies. Nozzle caulking is the result of carbon deposits formed between the injector needles and needle sheets. The deposition of carbon deposits is due to the exposure of the injector needles and sheets to the combustion gases, which potentially causes undesirable deformation of engine performance.

The Peugeot XUD9 A / L engine is a 1.9-liter displacement four-cylinder indirect injection diesel engine purchased from Peugeot Citroen Motors, specifically for the CEC PF023 method.

The test engine was equipped with a cleaned sprayer using an uneven sprayer needle. Airflow at various needle lift positions was measured on the flow apparatus before testing. The engine was operated for 10 hours under cycling conditions.

The tendency of the fuel to promote deposit formation on the fuel injector was determined by measuring the airflow of the injector nozzle again at the completion of the test and comparing this value with the values before the test. The results are shown for the airflow reduction percentages at various needle lift positions for all nozzles. The average value of airflow reduction in all four nozzles of a 0.1 mm needle lift was considered as the level of injector caulking for the provided fuel.

Example 11

A diesel fuel composition was prepared by adding 350 ppm of the Additive Composition 3 described in Example 5 to a base fuel having the specifications specified in Example 6. The fuel and base fuel were tested in a Peugeot XUD9 A / L engine according to the method described in Example 10. [ The results are shown in Table 7.

<Table 7>

Claims (19)

A first additive (i) comprising a quaternary ammonium salt and a second additive (ii) comprising a Mannich reaction product; Wherein the quaternary ammonium salt additive (i) is formed by reaction of a quaternizing agent other than an ester with a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of the formula (B1) or (B2);
&Lt; Formula (B1)

&Lt; Formula (B2)

Wherein R ² and R ³ are the same or different alkyl, alkenyl or aryl groups having 1 to 22 carbon atoms, X is a bond or an alkylene group having 1 to 20 carbon atoms, n is 0 to 20, and; m is 1 to 5; R ⁴ is hydrogen or C ₁ to C ₂₂ alkyl group)
Wherein the Mannich reaction product additive (ii)
(a) aldehyde;
(b) an amine; And
(c) Substituted phenol
&Lt; / RTI > is the product of the Mannich reaction;
Wherein the phenol is substituted with at least one branched hydrocarbyl group having a molecular weight of 200 to 3000
Diesel fuel composition. The process of claim 1, wherein the quaternizing agent is selected from the group consisting of dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates, hydrocarbyl substituted epoxides in combination with an acid, alkyl halides, alkyl sulfonates, sultones, hydrocarbyl A substituted carbonate, a substituted phosphate, a hydrocarbyl substituted borate, an alkyl nitrite, an alkyl nitrate, an N-oxide or a mixture thereof. The diesel fuel composition of claim 2, wherein the quaternizing agent is selected from hydrocarbyl substituted epoxides in combination with dialkyl sulfates, benzyl halides, hydrocarbyl substituted carbonates and acids. 4. A diesel fuel composition according to any one of claims 1 to 3, wherein the hydrocarbyl substituted acylating agent is reacted with a diamine compound of formula (B1). 5. The diesel fuel composition according to any one of claims 1 to 4, wherein the additive (i) is a salt of a tertiary amine prepared from dimethylaminopropylamine and polyisobutylene-substituted succinic anhydride. 6. A diesel fuel composition according to any one of claims 1 to 5, wherein component (a) used to prepare additive (ii) is formaldehyde. 7. The diesel fuel composition according to any one of claims 1 to 6, wherein the component (b) used to prepare the additive (ii) is a (poly) ethylene polyamine. 8. The diesel fuel composition according to any one of claims 1 to 7, wherein component (c) used to prepare additive (ii) is polyisobutylene-substituted phenol. 9. A process according to any one of claims 1 to 8, wherein the molar ratio of component (a) to component (b) in the Mannich reaction used to form additive (ii) is 2.2-1.01: Wherein the molar ratio of component (c) to component (c) is 1.99-1.01: 1 and the molar ratio of component (b) to component (c) is 1: 1.01-1.99. The process according to claim 9, wherein in the reaction used to prepare the Mannich additive, the molar ratio of component (a) to component (b) is 2-1.4: 1 and the molar ratio of component (a) : 1 and the molar ratio of component (b) to component (c) is 1: 1.1-1.7. 11. The diesel fuel composition according to any one of claims 1 to 10, wherein the diesel fuel comprises non-renewable Fischer Tropsch fuel and / or biodiesel. 12. A diesel fuel composition according to any one of claims 1 to 11, further comprising a fuel-containing catalyst comprising a metal selected from iron, cerium, Group I and Group II metals, platinum, manganese and mixtures thereof . An additive package providing a composition according to any one of claims 1 to 12 upon addition to diesel fuel. A method of operating a diesel engine, comprising burning a composition according to any one of claims 1 to 12 in an engine. The use of a quaternary ammonium salt additive (i) in the diesel fuel composition for improving the engine performance of a diesel engine when using a diesel fuel composition as defined in any one of claims 1 to 12, Use of the reaction product additive (ii). 16. The use of claim 15 for providing "clean" performance and / or "cleaning" performance. 17. Use according to claim 15 or 16 for improving the performance of a modern diesel engine with a high pressure fuel system and / or improving the performance of a conventional diesel engine. Use of a quaternary ammonium salt additive (i) and Mannich reaction product additive (ii) as defined in any one of claims 1 to 12 in a diesel fuel composition for inhibiting the formation of an emulsion. (1) to (12) for improving the demulsifying performance of a diesel fuel composition comprising a demethylating agent / demulsifier and a quaternary ammonium salt additive (i) as defined in any one of claims 1 to 12, (Ii) &lt; / RTI &gt; as defined in any one of the preceding claims.