RU2775969C2 - Compositions and methods, and applications related to them - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a fuel composition and a method for the production of a fuel composition. The method includes obtaining of quaternary ammonium salt by reaction of (a) tertiary amine with the formula R¹R²R³N, where R¹, R² and R³, each independently, is an optionally substituted hydrocarbyl group, with (b) an alkylating agent activated by acid in the presence of (c) a compound with the formula HOOCXCOO-(R⁴O)_n-R⁵, where R⁴ is an optionally substituted alkylene group, R⁵ is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, X is an alkylene group substituted with alkyl or alkenyl, and n is equal to 0 or a positive integer, provided that n is not equal to 0, if R⁵ is hydrogen; and mixing of quaternary ammonium salt with fuel; where n is a positive integer and/or X is CH₂CHR or CHRCH₂, where R is an alkyl or alkenyl group with from 20 to 24 carbon atoms.

EFFECT: obtaining a fuel composition.

27 cl, 3 tbl, 5 ex

Description

The present invention relates to novel quaternary ammonium compounds, compositions comprising these compounds, and related methods and uses. In particular, the invention relates to compositions, methods and uses for improving the performance of engines, especially diesel engines, using fuel additives. In particular, the invention relates to additives for diesel fuel compositions that are used in diesel engines with high pressure fuel systems.

Due to both consumer and legal requirements, diesel engines have become much more energy efficient over time, their performance has been improved, resulting in lower emissions.

Improving performance and reducing emissions to the atmosphere is made possible by improved combustion processes. In order to achieve sufficient atomization of the fuel necessary to improve combustion, fuel injection equipment has been developed that uses increased injection pressures and reduced diameters of the fuel injection nozzle orifices. At present, the pressure value of the fuel in the injection nozzle exceeds 1500 bar (1.5×10 ⁸ Pa). To achieve such pressures, work must be done on the fuel, which also raises the temperature of the fuel. High pressures and temperatures can cause decomposition of the fuel. In addition, more and more precision is required to establish the injection timing, the injection quantity, and also to control the fuel injection. Maintaining accurate fuel metering is essential to achieve optimum performance.

Diesel engines with high pressure fuel systems may include, but are not limited to, high power diesel engines and smaller passenger car diesel engines. Heavy duty diesel engines can include very powerful engines such as the MTU 4000 series diesel engine including 20-cylinder models designed primarily for ships with power outputs up to 4300 kW, or engines such as the Renault dXi 7 including 6 cylinders and having a power of approximately 240 kW. A typical passenger car diesel engine is the Peugeot DW10, which includes 4 cylinders and has a power of 100 kW or less depending on the model.

A common problem with diesel engines is clogging of injectors, in particular the injector body and injector nozzle. In addition, the fuel filter may be clogged. Injector nozzle clogging occurs when the nozzle becomes clogged with deposits formed by diesel fuel. Clogged fuel filters may be due to fuel being recirculated back to the fuel tank. Deposit formation intensifies as the fuel decomposes. The deposits can form as carbonaceous coke residues, varnish deposits, or sticky or tarry residues. Diesel fuels become more and more unstable as they are heated, in particular under pressure. Thus, increased fuel decomposition can occur in diesel engines with high pressure fuel systems. In recent years, in order to meet the requirements for reducing emissions into the atmosphere, the design of injection systems has been constantly updated. This leads to complication of nozzle designs and their low resistance to deposit formation.

Injector clogging can occur with any type of diesel fuel. However, some fuels may be particularly prone to fouling, or fouling may occur more rapidly when using these fuels. For example, increased deposit formation can occur when using fuels containing biodiesel and fuels containing metal compounds.

With complete or partial clogging of the injectors, the fuel supply is reduced, and the mixing of fuel with air deteriorates. Over time, this leads to a decrease in engine power, an increase in exhaust emissions into the atmosphere and a decrease in fuel economy.

It is known that deposits form in the spray channels of the nozzle, which leads to a decrease in flow and a decrease in power. The smaller the size of the nozzle nozzle opening, the higher the relative influence of deposit buildup. It is also known that deposits form at the nozzle tip. Such deposits adversely affect the fuel atomization pattern, resulting in reduced combustion efficiency and increased emissions to the atmosphere, as well as increased fuel consumption.

In addition to these "exterior" deposits at the nozzle orifice and at the nozzle tip that impede fuel flow and cause power loss, deposits can form inside the injector body, causing additional problems. These deposits can be called internal diesel injector deposits (abbreviated as VOFD, from the English internal diesel injector deposit, abbreviated as IDID). WOFDs are additionally formed inside the nozzle on important moving parts. They can impede the movement of such parts, negatively affecting the injection timing and the amount of fuel injected. Since modern diesel engines must operate with very high precision, these deposits can seriously degrade performance.

The formation of VOFD causes a number of problems, including reduced power and reduced fuel economy due to less than optimal dosing and combustion of fuel. Initially, the engine may experience cold start problems and/or the engine may run rough. The formation of such deposits can also lead to more serious clogging of the nozzles. This occurs if the deposits formed impede the movement of the nozzle parts, causing the nozzle to stop working. Clogging of some or all of the injectors can lead to a complete engine stop.

Those skilled in the art recognize that the formation of VOPDs is a serious problem, and the organization in charge of this branch of technology, i.e. The Co-ordinating European Council (CEC) has developed a new engine test. A DW10C engine definition has been developed to distinguish between fuels that do not cause detectable deposits and fuels that produce deposits that impair the engine's ability to start easily to an unacceptable degree. The objective of the test is to be able to classify fuels according to their ability to form VOFD in direct injection common rail diesel engines.

The inventors of the present invention conducted a study of internal deposits on diesel injectors and found that these deposits contain a number of components. In addition to carbonaceous deposits, varnish deposits and/or carboxylate residues present can lead to jamming (jamming caused by clogging) of the nozzle.

Lacquer deposits are varnish-like deposits that are insoluble in fuels and common organic solvents. Analysis of some lacquer deposits was found to contain amide functional groups, suggesting that they are formed due to the presence of substances containing low molecular weight amides in the fuel.

Carboxylate residues can enter the fuel from various sources. According to the invention, carboxylate residues are understood to mean salts of carboxylic acids. They may be short chain carboxylic acid residues, but more often they are long chain fatty acid residues. Carboxylic acid residues may be present as ammonium and/or metal salts. Both carboxylic acids and metals can enter diesel fuel from a variety of sources. Carboxylic acids may result from fuel oxidation, may be formed during combustion, and are typically added to fuels as lubricity additives and/or corrosion inhibitors. Residual fatty acids may be present in the fatty acid methyl esters contained in biodiesel, and in addition they may be present as by-products in other additives. Fatty acid derivatives may also be present in the fuel, which may react or decompose to form carboxylic acids.

Various metal compounds may be present in fuel compositions. They can result from fuel contamination during production, storage, transport or use, or from fuel additive contamination. Metal compounds can also be intentionally added to the fuel. For example, transition metals are sometimes added to fuels as fuel-borne catalysts (fuel catalysts), for example, to improve the performance of diesel particulate filters (diesel particulate filters).

The present inventors believe that one of the many causes of injector sticking is the result of reactions of metal or ammonium compounds with carboxylic acid particles present in the fuel. For example, nozzle jamming occurs when the fuel is contaminated with sodium compounds. Sodium contamination can occur for a number of different reasons. For example, the washing step used in the hydrodesulfurization process may include the use of sodium hydroxide, the presence of which can lead to the formation of contaminants. Sodium can also enter the fuel as a result of the use of pipeline corrosion inhibitors containing sodium. Alternatively, the contamination may be due to the presence of calcium, for example, released as a result of interaction with the lubricant or as a result of contamination by the lubricant, or by the ingress of calcium chloride found in salt used in processing in oil refineries. Other contaminating metals may be present, such as from water cushions at the bottom of oil tanks during transport.

It is believed that one of the significant causes of nozzle jamming is the contamination of diesel fuel with carboxylic acid salts, which are formed as a result of the action of metal compounds. Another important cause of nozzle jamming is the formation of lacquer deposits.

One option for dealing with HFFD and nozzle sticking due to carboxylate salts is to eliminate the source of the metal and/or carboxylic acid contaminant, or try to eliminate the carboxylic acids that cause the most severe problems. Such attempts have not been completely successful, ie there is still a need to create additives that enable the regulation of the formation of VOPD.

Deposit control additives are often included in fuels to control deposits in the nozzle or nozzle tip. In the context of the present invention, they may be referred to as "external deposits on the nozzles". Additives are also used to control the formation and condition of deposits on vehicle fuel filters. However, it has been found that additives suitable for controlling "external deposits" and deposits on fuel filters do not always control the formation of HFOs. Thus, the challenge for additive manufacturers is to provide more effective detergents.

It is an object of the present invention to provide methods and their uses for improving the performance of a diesel engine, in particular a diesel engine incorporating a high pressure fuel system. This can be achieved, for example, by preventing or reducing the formation of VOFDs and/or reducing or removing existing VOFDs. The invention provides methods and applications for controlling "external injector deposits" and/or fuel filter deposits.

The reduction or prevention of deposit formation can be considered as providing a "keep clean" characteristic. The reduction or removal of existing deposits can be seen as providing a "clean-up" characteristic. The object of the present invention is to provide "cleaning" and/or "cleaning" characteristics.

Many compounds of various types are known in the art and are used as detergent additives in petroleum fuel compositions to control deposits in engines. The present invention relates to new quaternary ammonium compounds having an ester counterion, which is a partial (partial) ester of a polycarboxylic acid, which can be used as detergent additives.

The first aspect of the present invention relates to a quaternary ammonium compound having the formula (I):

where each of R ⁰ , R ¹ , R ² and R ³ independently represents an optionally substituted hydrocarbyl group, X represents a connecting group, R ⁴ represents an optionally substituted alkylene group, R ⁵ represents hydrogen or an optionally substituted alkyl, alkenyl or aryl group group, and m is 0 or a positive integer, provided that n is not 0 if R5 is hydrogen.

Preferably, each of R ⁰ , R ¹ , R ² and R ³ is an optionally substituted alkyl, alkenyl or aryl group.

According to the present invention, the terms "hydrocarbyl substituent" or "hydrocarbyl group" have their usual meanings, which are well known to those skilled in the art. In particular, this term means a group containing a carbon atom directly attached to the rest of the molecule, and having mainly hydrocarbon character. Examples of hydrocarbyl groups include:

(i) hydrocarbon groups, i.e. aliphatic (which may be saturated or unsaturated, straight or branched, e.g. alkyl or alkenyl), alicyclic (e.g. cycloalkyl, cycloalkenyl) substituents, and aromatic (comprising aromatic groups substituted with aliphatic and epicyclic groups) substituents, as well as cyclic substituents in which the cycle is completed by another part of the molecule (for example, two substituents together form a cycle);

(ii) substituted hydrocarbon groups, i.e. substituents containing non-hydrocarbon groups (for example, halogen (in particular chlorine and fluorine), hydroxy, alkoxy, keto, acyl, cyano, mercapto, alkylmercapto, amino, alkylamino -, nitro-, nitroso- and sulfoxy group):

(iii) heterosubstituents, that is, substituents which, despite their predominantly hydrocarbon character in the context of the present invention, contain atoms other than carbon in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and are included in substituents such as pyridyl, furyl, thienyl, and imidazolyl. In general, for every ten carbon atoms of the hydrocarbyl group, there are no more than two, preferably no more than one, non-hydrocarbon substituent; typically, the hydrocarbyl group does not contain non-hydrocarbon substituents.

Unless otherwise indicated, reference herein to optionally substituted alkyl groups may include aryl-substituted alkyl groups, and reference to optionally substituted aryl groups may include alkyl-substituted or alkenyl-substituted aryl groups.

Quaternary ammonium salt according to the present invention can be obtained using any suitable methods. Suitable methods are known to the person skilled in the art.

In some embodiments, R ⁰ may be a lower alkyl group and the quaternary ammonium compound is prepared from an ester having the formula R ⁰ OOCXCOO(R ⁴ O) _n R ⁵ . In such embodiments, R ⁰ is preferably methyl.

In some embodiments, the quaternary ammonium salt can be prepared by reacting an ester quaternizing agent having the formula RCOOR ⁰ followed by an ion exchange reaction with an acid having the formula HOOCXCOO(R ⁴ O) _n R ⁵ . In such embodiments, R may be an optionally substituted aryl or alkyl group or an ester. For example, R ⁰ may be methyl and RCOOR ⁰ may be methyl salicylate or dimethyl oxalate.

In some embodiments, R ⁰ is a C1-C5 alkyl group, preferably methyl.

In preferred embodiments, the quaternary ammonium compound is prepared from a tertiary amine, an acid-activated alkylating agent, and an acid. Thus, R ⁰ preferably represents the remainder of the alkylating agent.

In preferred embodiments, the first aspect of the present invention relates to a quaternary ammonium compound, which is the product of the reaction:

(a) a tertiary amine having the formula R ¹ R ² R ³ N;

(b) an acid-activated alkylating agent; and

(c) a compound having the formula HOOCXCOO-(R ⁴ O) _n -R ⁵ , wherein R ⁴ is an optionally substituted alkylene group, R ⁵ is hydrogen or an optionally substituted alkyl, alkenyl, or aryl group, and n is 0 or positive an integer, provided that n is not equal to 0 if R ⁵ is hydrogen.

The second aspect of the present invention relates to a process for preparing a quaternary ammonium salt which comprises reacting (a) a tertiary amine having the formula R ¹ R ² R ³ N with (b) an acid-derived alkylating agent in the presence of (c) a compound having the formula HOOCXCOO -(R ⁴ O) _n -R ⁵ where R ⁴ is an optionally substituted alkylene group, R ⁵ is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not equal to 0 if R ⁵ is hydrogen.

The preferred features of the first and second aspects of the invention are discussed below.

According to the invention, any feature of any aspect of the invention may be combined with any feature of any other aspect, as appropriate.

X is a connecting group. Preferably X is an optionally substituted alkylene or arylene group. X is discussed in more detail below.

The present invention relates to a composition, method and use, including Quaternary ammonium salt. In the present work, the compound may be referred to as "quaternary ammonium salt" or "quaternary ammonium compound".

The quaternary ammonium salt may include one compound. In some embodiments, mixtures containing more than one quaternary ammonium salt additive may be used. Reference herein to a "quaternary ammonium salt" according to the invention or a "quaternary ammonium salt" includes mixtures comprising two or more of these compounds.

Component (a) used to obtain Quaternary ammonium salts according to the present invention is a tertiary amine. Any suitable tertiary amine may be used.

In some embodiments according to the present invention, the tertiary amine may be a small compound having low complexity and low molecular weight. In some embodiments, the tertiary amine may be a complex and/or high molecular weight molecule that contains a tertiary amine moiety.

Tertiary amines according to the present invention preferably do not include primary or secondary amino groups. In some embodiments, they can be derived from compounds containing primary or secondary amino groups, but preferably they are then reacted to form additional tertiary amines. The tertiary amine used as component (a) may contain more than one tertiary amino group. However, tertiary amines containing primary or secondary amino groups are included within the scope of the invention, provided that such groups do not interfere with quaternization of the tertiary amine.

Tertiary amines suitable for use according to the invention are preferably compounds having the formula R ¹ R ² R ³ N, where each of R ¹ , R ² and R ³ independently represents an optionally substituted alkyl, alkenyl or aryl group.

R ¹ , R ² and R ³ may be the same or different. In some preferred embodiments, R ¹ and R ² are the same and R ³ is different.

Preferably, R ¹ and R ² are each independently an optionally substituted alkyl, alkenyl or aryl group containing 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms.

Each of R ¹ and R ² may be optionally substituted with one or more groups selected from halogen (particularly chlorine and fluorine), hydroxy, alkoxy, keto, acyl, cyano, mercapto, alkylmercapto, dialkylamino , nitro, nitroso and sulfoxy groups. The alkyl groups of such substituents may be further substituted.

Preferably, R ¹ and R ² are each independently an optionally substituted alkyl or alkenyl group. Preferably, R ¹ and R ² are each independently an optionally substituted alkyl group. Preferably, R ¹ and R ² are each independently an optionally substituted alkyl or alkenyl group containing 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, eg 1 to 6 carbon atoms.

In some embodiments, each of R ¹ and R ² is methyl, and R ³ is a C ₆ -C ₃₆ -, preferably C ₁₀ -C ₃₀ -alkyl or -alkenyl group.

In some embodiments, R ¹ is methyl, and each of R ² and R ³ is a C ₆ -C ₃₆ -, preferably C ₁₀ -C ₃₀ -alkyl or -alkenyl group.

Preferably R ¹ is an optionally substituted alkyl or alkenyl group, preferably containing 1 to 10, preferably 1 to 4 carbon atoms. Preferably R ¹ is an alkyl group. It may be a substituted alkyl group, for example a hydroxy substituted alkyl group. Preferably R ¹ is an unsubstituted alkyl group. The alkyl chain may be straight or branched. In some preferred embodiments, R ¹ is selected from methyl, ethyl, propyl, and butyl, including their isomers. In some particularly preferred embodiments, R ¹ is methyl or ethyl.

Preferably R ² is an optionally substituted alkyl or alkenyl group, preferably having 1 to 10, more preferably 1 to 4 carbon atoms. Preferably R ² is an alkyl group. It may be a substituted alkyl group, for example a hydroxy substituted alkyl group. Preferably R ² is an unsubstituted alkyl group. The alkyl chain may be straight or branched. In some preferred embodiments, R ² is selected from methyl, ethyl, propyl, and butyl, including their isomers. In some particularly preferred embodiments, R ² is methyl or ethyl.

In some embodiments, R ³ is an optionally substituted alkyl or alkenyl group containing from 1 to 50 carbon atoms, preferably from 1 to 40 carbon atoms, more preferably from 1 to 30 carbon atoms, more preferably from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, more preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, such as 1 to 6 carbon atoms. Suitable substituents include halogen (particularly chlorine and fluorine), hydroxy, alkoxy, keto, acyl, cyano, mercapto, alkylmercapto, amino, alkylamino, nitro, nitroso, sulfoxy, amido, an alkylamido, imido and alkylimido group. The alkyl groups of such substituents may be further substituted.

In some embodiments, R ³ is an optionally substituted alkyl or alkenyl group, preferably having 1 to 10, more preferably 1 to 4 carbon atoms. Preferably R ³ is an optionally substituted alkyl group. In some embodiments, R ³ is an unsubstituted alkyl group, for example, C ₁ -C ₁₀ -, preferably C ₁ -C ₆ - or C ₁ -C ₄ -alkyl group. The alkyl group may be straight or branched.

In some preferred embodiments, R ³ is a substituted alkyl group. Preferred substituents include alkoxy and hydroxy groups.

In some embodiments, one or more heteroatoms, such as one or more oxygen atoms, may be inserted into the alkyl chain.

In some preferred embodiments, R ³ is a hydroxy-substituted alkyl group. The alkyl chain may be straight or branched. In some particularly preferred embodiments, R ³ is a hydroxyethyl group.

In one embodiment, R ³ is a hydroxyethyloxyethyl group.

In some embodiments, each of R ¹ , R ² and R ³ is independently selected from an alkyl or hydroxyalkyl group containing 1 to 12, preferably 1 to 6, more preferably 1 to 4 carbon atoms.

In some embodiments, trialkylamines and hydroxyalkyldialkylamines are particularly preferred.

In some embodiments, R ³ is an optionally substituted hydrocarbyl group, eg an optionally substituted hydrocarbyl group, containing 1 to 300 carbon atoms, eg 1 to 200 carbon atoms. R ³ may be an optionally substituted hydrocarbyl group having a number average molecular weight of 100 to 5000, preferably 500 to 2500.

In some embodiments, R ³ is an optionally substituted aryl group or an alkaryl group. For example, R ³ may be benzyl.

In some embodiments, R ³ is an optionally substituted alkyl or alkenyl group. R ³ may be an unsubstituted alkyl or alkenyl group. Preferably R ³ is a substituted alkyl or alkenyl group containing from 1 to 200 carbon atoms.

In some embodiments, R ³ is an alkyl group or an alkenyl group containing from 10 to 36 carbon atoms.

In some embodiments, R ³ is a polyisobutenyl group, preferably a polyisobutenyl group, having a molecular weight of 100 to 5000, preferably 300 to 4000, more preferably 450 to 2500, such as 500 to 2000 or 600 to 1500.

In some embodiments, R ³ is an optionally substituted alkylenephenol moiety and the tertiary amine R ¹ R ² R ³ N is the product of a Mannich reaction between an aldehyde, an optionally substituted phenol, and an amine. Preferably the aldehyde is formaldehyde. The amine used to prepare the Mannich compound may be a monoamine and R ³ will have the structure (A):

The amine used to prepare the Mannich compound may be a polyamine containing at least one tertiary amino group, and R ³ may have the structure (B):

In structures (A) and (B), n is 0 to 4, preferably 1, each R ^x is an optionally substituted hydrocarbyl group, R ^y is an optionally substituted alkyl, alkenyl or aryl group; and L is a connecting group.

R ^y and L together may form a heterocyclic group.

R ^y is preferably an alkyl group, preferably an unsubstituted alkyl group. R ^y is preferably a C ₁ -C ₄ alkyl group.

Preferably L is an optionally substituted alkylene group, preferably an alkylene group containing 1 to 10, preferably 1 to 6 carbon atoms. More preferably L is an unsubstituted alkylene group, such as ethylene, propylene or butylene. Most preferably L is a propylene group.

In some preferred embodiments, the phenol includes an ortho-methyl substituent and the other Rx substituent is in the para position.

In one preferred embodiment, n is 1 and the optionally substituted hydrocarbyl substituent R is preferably para to the hydroxyl group.

The optionally substituted hydrocarbyl substituent R ^x of the phenol may contain from 6 to 400 carbon atoms, preferably from 30 to 180 carbon atoms, for example from 10 or from 40 to 110 carbon atoms. This hydrocarbyl substituent may be derived from an olefin or a polyolefin.

Polyolefins from which a hydrocarbyl substituent can be derived can be prepared by polymerizing olefin monomers by well known polymerization techniques and also commercially available.

Some preferred polyolefins include polyisobutylenes having a number average molecular weight of 200 to 3000, in another example 400 to 2500, and in another example 400 or 500 to 1500.

In some embodiments, the phenol may include a low molecular weight alkyl substituent, for example, a phenol containing one or more alkyl chains having a total of less than 28 carbon atoms, preferably less than 20 carbon atoms, more preferably less than 14 carbon atoms.

Preferred may be a phenol substituted with a monoalkyl preferably having 4 to 20 carbon atoms, preferably 8 to 16 carbon atoms, for example a phenol having a C ₁₂ alkyl substituent.

In some embodiments, R ³ may include an ether, amide, or ester group.

In some embodiments, R ³ includes a succinimide moiety. R ³ may have the following formula:

where R ^z is an optionally substituted hydrocarbyl group and L is a connecting group.

In some embodiments, the optionally substituted hydrocarbyl substituent R ^z may contain 6 to 36 carbon atoms, preferably 8 to 22, such as 10 to 18 or 16 to 18 carbon atoms.

In some embodiments, the optionally substituted hydrocarbyl substituent R ^z may contain from 6 to 400 carbon atoms, preferably from 30 to 180 carbon atoms, for example, from 10 or from 40 to 110 carbon atoms. Such a hydrocarbyl substituent may be derived from an olefin or a polyolefin.

Some preferred polyolefins include polyisobutylenes having a number average molecular weight of 200 to 3000, in another example 400 to 2500, and in another example 400 or 500 to 1500.

Preferably L is an optionally substituted alkylene group, preferably an alkylene group containing 1 to 10, preferably 1 to 6 carbon atoms. More preferably L is an unsubstituted alkylene group, such as ethylene, propylene or butylene. Most preferably L is a propylene group.

R ³ may preferably be selected from an optionally substituted alkyl or alkenyl group having 1 to 10 carbon atoms, an optionally substituted hydrocarbyl group having a molecular weight of 100 to 5000, an optionally substituted alkylenephenol moiety, and an optionally substituted alkylene succinimide group.

Tertiary amines suitable for use as component (a) include simple alkylamino compounds and hydroxyalkylamino compounds, trialkylamino compounds having a high molecular weight substituent, Mannich reaction products including a tertiary amine and substituted acylated amines or alcohols including a tertiary amine.

Simple alkylamino and hydroxyalkylamino compounds are preferably compounds having the formula R ¹ R ² R ³ N, where each of R ¹ , R ² and R ³ represents an alkyl group or a hydroxyalkyl group. All R ¹ , R ² and R ³ may be the same or different. Preferably, R ¹ , R ² and R ³ are each independently selected from an alkyl or hydroxyalkyl group containing 1 to 10, preferably 1 to 6 carbon atoms, eg 1 to 4 carbon atoms. Each of R ¹ , R ² and R ³ can be independently selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxypentyl and hydroxyhexyl. Component (a) may be a trialkylamine, dialkylhydroxyalkylamine, dihydroxyalkylalkylamine or trihydroxyalkylamine. There are many different compounds of this type and they are known to those skilled in the art.

In some embodiments, the amine may include alkyl or hydroxyalkyl groups reacted with an epoxy compound (eg, ethylene oxide or propylene oxide) to form an ether.

Trialkylamino compounds having a high molecular weight substituent suitable for use in the invention are typically polyalkene substituted amines containing at least one tertiary amino group.

The polyalkene-substituted amines of the present invention having at least one tertiary amino group can be prepared from an olefin polymer and an amine, for example ammonia, monoamines, polyamines, or mixtures of the like. They can be obtained in various ways, such as the methods discussed and cited in the document US 2008/0113890.

Preferably, the polyalkene substituent of the polyalkene-substituted amine is derived from polyisobutylene.

Amines that can be used to prepare the polyalkene-substituted amine include ammonia, monoamines, polyamines, or mixtures of these substances, including mixtures of various monoamines, mixtures of various polyamines, and mixtures of monoamines and polyamines (which include diamines). Amines include aliphatic, aromatic, heterocyclic and carbocyclic amines. Preferred amines are usually substituted with at least one hydrocarbyl group containing from 1 to about 50 carbon atoms, preferably from 1 to 30 carbon atoms. Especially preferred are saturated aliphatic hydrocarbon radicals.

Monoamines and polyamines preferably include at least one primary or secondary amino group.

The number average molecular weight of polyalkene-substituted amines can be from 500 to 5000 or from 500 to 3000, for example from 1000 to 1500.

Any of the above polyalkene substituted amines that are secondary or primary amines can be alkylated with alkylating agents to form tertiary amines. Suitable alkylating agents and methods for their use are known to those skilled in the art.

Mannich reaction products containing a tertiary amine suitable for use as component (a) are discussed in US 2008/0052985.

A Mannich reaction product containing a tertiary amino group is obtained from the reaction of a phenol having an optionally substituted hydrocarbyl substituent, an aldehyde and an amine. The phenol having an optionally substituted hydrocarbyl substituent is preferably the phenol discussed above in the present description.

Preferably, the phenol having an optionally substituted hydrocarbyl substituent is polyisobutenyl-substituted phenol or polyisobutenyl-substituted cresol.

The aldehyde used to form the Mannich reaction product detergent may contain from 1 to 10 carbon atoms, and is usually formaldehyde or a reactive equivalent such as formalin or paraformaldehyde.

The amine used to make the Mannich reaction product detergent may be a monoamine or a polyamine.

Examples of monoamines and polyamines are known to those skilled in the art.

Preferred polyamines are polyethylenepolyamines.

In particularly preferred embodiments, the amine used to make the Mannich detergent product includes a diamine. Preferably it includes a primary or secondary amine which takes part in the Mannich reaction and an additional tertiary amine.

One preferred amine is dimethylaminopropylamine.

In preferred embodiments, the Mannich detergent product is a product directly obtained from the Mannich reaction and includes a tertiary amine. For example, an amine may include a single primary or secondary amine which, by Mannich reaction, forms a quaternized tertiary amine. Alternatively, the amine may include a primary or secondary amine that can undergo a Mannich reaction, as well as a tertiary amine that can undergo quaternization. However, the Mannich reaction product detergent may include a compound that was obtained by the Mannich reaction and then introduced into a reaction to form a tertiary amine; for example, a secondary amine can be produced in a Mannich reaction, which is then alkylated to give a tertiary amine.

Suitable preferred amines include dimethylamine and dibutylamine.

Substituted acylated amines or alcohols containing a tertiary amine suitable for use as component (a) include the reaction product of an acylating agent having an optionally substituted hydrocarbyl substituent and a compound containing an oxygen or nitrogen atom that can condense with said acylating agent and also has a tertiary amino group.

The acylating agent having an optionally substituted hydrocarbyl substituent is preferably a mono- or polycarboxylic acid (or its reactive equivalent), for example a substituted succinic, phthalic or propionic acid.

Preferred hydrocarbyl-substituted acylating agents that can be used to prepare component (D) are polyisobutenyl-substituted succinic acid derivatives. Preferred compounds are compounds containing a polyisobutenyl group whose molecular weight is from 100 to 5000, preferably from 300 to 4000, more preferably from 450 to 2500, for example, from 500 to 2000 or from 600 to 1500.

In some preferred embodiments, the tertiary amine includes compounds formed by the reaction of an acylating agent having an optionally substituted hydrocarbyl substituent and an amine having formula (II) or (III):

where R ⁶ and R ⁷ represent the same or different alkyl, alkenyl or aryl groups containing from 1 to 22 carbon atoms; A represents a bond or represents an alkylene group containing from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R ⁴ is hydrogen or a C ₁ -C ₂₂ alkyl group.

The reaction conditions discussed above are preferably chosen such that the resulting tertiary amine component (a) does not contain free acid groups. For example, for the reaction of a compound having formula (II) with an acylating agent derived from succinic acid, the reaction conditions or reactant ratio are chosen such that an imide or diamide is formed in the reaction. Monoamide is not formed. For the reaction of a compound having formula (III) with an acylating agent derived from succinic acid, the reaction conditions or reactant ratio are chosen such that a diester is formed in the reaction. A complex monoester is not formed.

When a compound having formula (II) is used, R ⁸ is preferably hydrogen or a C ₁ -C ₁₈ -, preferably a C ₁ -C ₁₆ -alkyl group. More preferably R ⁸ is selected from hydrogen, methyl, ethyl, propyl, butyl and their isomers. Most preferably R ⁸ is hydrogen.

If a compound having formula (III) 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 having formula (III) is an alcohol.

Preferably, an acylating agent having an optionally substituted hydrocarbyl substituent is reacted with a diamine having formula (II).

R ⁶ and R ⁷ are the same or different alkyl, alkenyl or aryl groups containing from 1 to 22 carbon atoms. In some embodiments, R ⁶ and R ⁷ can be connected to each other and form a cyclic structure, for example, a piperidine, imidazole or morpholine ring. Thus, R ⁶ and R ⁷ can together form an aromatic and/or heterocyclic moiety. R ⁶ and R ⁷ may be branched alkyl or alkenyl groups. Each of these may be substituted, for example, with a hydroxyl or alkoxy substituent.

Preferably, R ⁶ and R ⁷ are each independently a C ₁ -C ₁₆ alkyl group, preferably a C ₁ -C ₁₀ alkyl group. R ⁶ and R ⁷ may independently represent methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, or an isomer of any of them. Preferably, R ⁶ and R ⁷ are each independently C ₁ -C ₄ alkyl. Preferably R ⁶ is methyl. Preferably R ⁷ is methyl.

A represents a bond or an alkylene group containing from 1 to 20 carbon atoms. A is preferably an alkylene group having 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. Most preferably A is an ethylene, propylene or butylene group, in particular a propylene group.

Examples of compounds having formula (II) suitable for use according to the invention are known to those skilled in the art.

In some preferred embodiments, the compound having formula (II) is selected from dimethylaminopropylamine, N,N-diethyl-1,3-diaminopropane, N,N-dimethylethylenediamine, N,N-diethylethylenediamine, N,N-dibutylethylenediamine, or a combination of these compounds. .

Examples of compounds having formula (III) suitable for use according to the invention are known to those skilled in the art.

In some preferred embodiments, the compound having formula (III) is selected from triisopropanolamine, 1-[2-hydroxyethyl]piperidine, 2-[2-(dimethylamine)ethoxy]-ethanol, N-ethyldiethanolamine, N-methyldiethanolamine, N-butyldiethanolamine , N,N-diethylaminoethanol, N,N-dimethylaminoethanol, 2-dimethylamino-2-methyl-1-propanol, or combinations of these compounds.

A particularly preferred compound having formula (II) is dimethylaminopropylamine.

Other particularly preferred tertiary amines (a) are obtained by the reaction of a compound containing a primary amino group and a tertiary amino group and polyisobutenyl-substituted succinic acid. A particularly preferred amine-containing compound having primary and tertiary amino groups is dimethylaminopropylamine. The molecular weight of the polyisobutenyl substituent is preferably 300 to 2500, preferably 500 to 1500. Thus, a particularly preferred compound suitable for use as component (a) is a polyisobutenyl-substituted succinimide derived from dimethylaminopropylamine.

Preferred tertiary amines suitable for use as component (a) include N,N-dimethylethanolamine, dimethyloctadecylamine, tall oil N-methyl N,N-diamine, N,N-diethylethanolamine, triethylamine, tripropylamine and tributylamine.

Particularly preferred tertiary amines suitable for use as component (a) include N,N-dimethylethanolamine, N,N-diethylethanolamine, triethylamine and tributylamine.

Other suitable amines that can be used as component (a) include small cyclic amines. They include, for example, compounds derived from N-alkylheterocycles, preferably selected from pyrrolidine, piperidine, morpholine, piperazine, pyrrole, imidazole and dihydropyrrole, pyridine, pyrimidine, isoxazole and oxazole. Suitable starting amine-containing materials of this type are discussed, for example, in the patent application of the applicant of the present invention PCT/GB2016/052312, which is currently under consideration.

In some embodiments, component (a) is selected from:

- trialkylamines, in which each alkyl group contains from 1 to 6, preferably from 1 to 4 carbon atoms;

- dimethylalkyl- or -alkenylamines, in which the alkyl or alkenyl group contains from 6 to 36, preferably from 10 to 30 carbon atoms;

- tertiary amines, in which each substituent is selected from alkyl, hydroxylalkyl and hydroxyalkyloxyalkyl groups containing from 1 to 12, preferably from 1 to 6 carbon atoms.

Preferred amines suitable for use as component (a) are trialkylamines, in which each alkyl group contains from 1 to 12, preferably from 1 to 6 carbon atoms, and in which each alkyl group may be substituted by hydroxyl and/or substituted by an atom oxygen in the carbon chain.

Preferably component (a) is an amine having the formula R ¹ R ² R ³ N, where each of R ¹ , R ² and R ³ independently represents an unsubstituted alkyl group containing from 1 to 6 carbon atoms, a hydroxy-substituted alkyl group containing from 1 to 6 carbon atoms, or a hydroxyalkyloxyalkyl group containing from 1 to 6 carbon atoms.

A hydroxyalkyloxyalkyl group refers to a group having the formula HOR ^a OR ^b , where R ^a and R ^b are each an alkylene group. They can be formed by alkylation of a hydroxyalkyl substituent with an epoxide.

Most preferably component (a) is an amine having the formula R ¹ R ² R ³ N, where each of R ¹ , R ² and R ³ independently represents an unsubstituted alkyl group containing from 1 to 6 carbon atoms, or a hydroxy-substituted alkyl group containing from 1 to 6 carbon atoms.

Component (b) used to prepare the quaternary ammonium compound of the present invention is, in preferred embodiments, an acid-activated alkylating agent. Preferred acid-activated alkylating agents are epoxy compounds.

Any suitable epoxy compound may be used. Suitable epoxy compounds are compounds having the formula:

where each of R ⁹ , R ¹⁰ , R ¹¹ , R ¹² is independently selected from hydrogen or an optionally substituted alkyl, alkenyl or aryl group.

Thus, in such embodiments, R ⁰ represented in formula (I) is preferably a group having the formula:

Preferably at least one of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² is hydrogen. Preferably, at least two of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are hydrogen atoms. Most preferably, three of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are hydrogen atoms. Each of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be hydrogen.

In the above structures and the following definitions, R ⁹ and R ¹⁰ are interchangeable, and thus, if these groups are different, either an enantiomer or a diastereomer can be used as component (b).

In the above structures and the following definitions, R ¹¹ and R ¹² are interchangeable and thus, if these groups are different, either an enantiomer or a diastereomer can be used as component (b).

Preferably R ⁹ is hydrogen or an optionally substituted alkyl, alkenyl or aryl group preferably containing 1 to 10, preferably 1 to 4 carbon atoms. Preferably R ⁹ is hydrogen or an alkyl group. Most preferably R ⁹ is hydrogen.

Preferably R ¹⁰ is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, preferably containing from 1 to 10 carbon atoms. For example, R ¹⁰ may be benzyl.

In some preferred embodiments, R ¹⁰ is an optionally substituted aryl group. For example, R ¹⁰ may be phenyl.

In some preferred embodiments, R ¹⁰ is an optionally substituted alkyl or alkenyl group. Preferably R ¹⁰ is an alkyl group, for example an unsubstituted alkyl group. R ¹⁰ may be an alkyl group containing 1 to 12, for example 1 to 8 or 1 to 4 carbon atoms.

Preferably R ¹⁰ is hydrogen or an alkyl group. Most preferably R ¹⁰ is hydrogen.

Preferably R ¹¹ is hydrogen or an optionally substituted alkyl, alkenyl or aryl group preferably containing 1 to 10, preferably 1 to 4 carbon atoms. Preferably R ¹¹ is hydrogen or an alkyl group. Most preferably R ¹¹ is hydrogen.

Preferably R ¹² is hydrogen or an optionally substituted alkyl, alkenyl or aryl group.

In some preferred embodiments, R ¹² is an optionally substituted aryl group. For example, R ¹² may be phenyl.

In some preferred embodiments, R ¹² is an optionally substituted alkyl or alkenyl group. R ¹² may be an alkyl group, for example an unsubstituted alkyl group. R ¹² may be an alkyl group containing from 1 to 50 carbon atoms, preferably from 1 to 30 carbon atoms, more preferably from 1 to 20 carbon atoms, more preferably from 1 to 12 carbon atoms, for example, from 1 to 8 or from 1 up to 4 carbon atoms.

In some embodiments, R ¹² is an alkyl group containing 6 to 20 carbon atoms, preferably 8 to 16 carbon atoms.

In some embodiments, R ¹² is hydrogen.

In some preferred embodiments, R ¹² is a CH ₂ OR ¹³ or CH ₂ OCOR ¹⁴ moiety, where each of R ¹³ and R ¹⁴ may be an optionally substituted alkyl, alkenyl, or aryl group.

R ¹³ is preferably an optionally substituted alkyl or aryl group, preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms. When R ¹³ is an alkyl group, it may be straight or branched. In some embodiments, R ¹³ is a branched group. R ¹³ may be an optionally substituted phenyl group.

In one embodiment, R ¹³ is 2-methylphenyl. In another embodiment, R ¹³ is CH ₂ C(CH ₂ CH ₃ )CH ₂ CH ₂ CH ₂ CH ₃ .

R ¹⁴ may be an optionally substituted alkyl, alkenyl or aryl group.

R ¹⁴ is preferably an optionally substituted alkyl or aryl group, preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms. When R ¹⁴ is an alkyl group, it may be straight or branched. In some preferred embodiments, R ¹⁴ is a branched group. R ¹⁴ may be an optionally substituted phenyl group.

In one embodiment, R ¹⁴ is C(CH ₃ )R ₂ where each R is an alkyl group. The R groups may be the same or different.

Component (b) is preferably an epoxide. Thus, the present invention relates to a quaternary ammonium compound, which is a product of the reaction:

(a) a tertiary amine having the formula R ¹ R ² R ³ N;

(b) epoxide; and

(c) a compound having the formula HOOCXCOO(R ⁴ O)R ⁵ , wherein R ⁴ is an optionally substituted alkylene group, R ⁵ is hydrogen or an optionally substituted alkyl, alkenyl, or aryl group, and n is 0 or a positive integer, with the proviso that n is not 0 if R ⁵ is hydrogen.

Preferred epoxy compounds suitable for use as component (b) include styrene oxide, ethylene oxide, propylene oxide, butylene oxide, epoxyhexane, octenoxide, stilbene oxide and other alkyl and alkenyl epoxides containing from 2 to 50 carbon atoms.

Other suitable epoxy compounds include glycidyl ethers and glycidyl esters, for example, glycidyl-2-methylphenyl ether and versatic acid glycidyl ester.

Preferably, component (b) may be selected from styrene oxide, ethylene oxide, propylene oxide, butylene oxide, epoxyhexane, octenoxide, stilbene oxide, 2-ethylhexylglycidyl ether, 1,2-epoxydecane and other alkyl and alkenyl epoxides containing from 2 to 50 carbon atoms.

Preferably component (b) is selected from styrene oxide, propylene oxide, butylene oxide and 2-ethylhexylglycidyl ether.

More preferably component (b) is selected from propylene oxide, butylene oxide and 2-ethylhexylglycidyl ether.

Quaternary ammonium salt according to the present invention includes an anion having the formula -OOCXCOO(R ⁴ O) _n R ⁵ .

Preferably, the quaternary ammonium salt is prepared by the reaction of (a) a quaternary amine; (b) epoxide; and (c) an acid having the formula HOOCXCOO(R ⁴ O) _n R ⁵ .

The compound having the formula HOOCXCOO(R ⁴ O) _n R ⁵ is preferably a half-ester which is the reaction product of an optionally substituted dicarboxylic acid or its anhydride and an alcohol having the formula HO(R ⁴ O) _n R ⁵ .

In some embodiments, the dicarboxylic acid or anhydride has no substituents. In preferred embodiments, the additive is derived from a hydrocarbyl-substituted dicarboxylic acid or anhydride thereof.

Suitable dicarboxylic acids include maleic acid, glutaric acid, fumaric acid, oxalic acid, malonic acid, pimelic acid, suberic acid, adipic acid, phthalic acid, succinic acid, azelaic acid, sebacic acid, and dimerized fatty acids.

In one embodiment, component (c) is the reaction product of an optionally substituted polycarboxylic acid or anhydride thereof, wherein the acid is selected from pyromellitic acid, malonic acid, sebacic acid, and succinic acid. Preferably component (c) is an optionally substituted succinic acid or its anhydride.

In some embodiments, a compound having the formula HOOCXCOO(R ⁴ O)R ⁵ (component (c)) is prepared from a dimerized fatty acid. Such compounds are formed by the dimerization of unsaturated fatty acids, for example unsaturated fatty acids containing 6 to 50, preferably 8 to 40, more preferably 10 to 36, for example 10 to 20 carbon atoms or 16 to 20 carbon atoms.

Such dimerized fatty acids may contain 12 to 100 carbon atoms, preferably 16 to 72 carbon atoms, suitably 20 to 40 carbon atoms, eg 32 to 40 carbon atoms.

These compounds are well known in the art, in particular they are used as corrosion inhibitors. Particularly preferred dimerized fatty acids are mixtures of C36 dimeric acids, such as those obtained by dimerizing oleic acid, linoleic acid, and mixtures comprising oleic and linoleic acids, such as tall oil fatty acids.

The quaternary ammonium compound having formula (I) includes a connecting group X. Preferably X includes a hydrocarbyl substituent. Preferably X is an optionally substituted arylene or alkylene group.

In some embodiments, component (c) is derived from phthalic acid or its anhydride having formula (A1) or formula (A2):

where each of R ^p , R ^q , R ^r and R ^s independently represents hydrogen or an optionally substituted hydrocarbyl group

Preferably, R ^p , R ^q , R ^r and R ^s are each hydrogen or an optionally substituted alkyl or alkenyl group. Preferably three of R ^p , R ^q , R ^r and R ^s are hydrogen atoms and the remaining radical is an optionally substituted C ₁ -C ₅₀₀ alkyl or alkenyl group, preferably a C ₂ -C ₁₀₀ alkyl or alkenyl group, preferably C ₆ -C ₅₀ alkyl or alkenyl group, preferably C ₈ -C ₄₀ alkyl or alkenyl group, more preferably C ₁₀ -C ₃₆ alkyl or alkenyl group, more preferably C ₁₂ -C ₂₂ alkyl or alkenyl group, more preferably C ₁₆ -C ₂₈ alkyl or alkenyl group, for example C ₂₀ -C ₂₄ alkyl or alkenyl group. The alkyl or alkenyl group may be straight or branched. Preferably R ^p , R ^q and R ^s are hydrogen atoms and R ^r is an optionally substituted alkyl or alkenyl group.

X in formula (I) is preferably an optionally substituted hydrocarbylene group. Preferably X is an optionally substituted alkylene group. Preferably X is a substituted alkylene group.

Preferably X is an alkylene group substituted with alkyl or alkenyl.

Preferably X is an alkylene group substituted with alkyl.

Preferably X is an alkylene group substituted with alkyl, where the alkylene group contains 1 to 10, preferably 1 to 6, more preferably 1 to 4, more preferably 2 or 3, and most preferably 2 carbon atoms in the alkylene chain.

In some preferred embodiments, X is CH ₂ CHR or CHRCH ₂ where R is an optionally substituted hydrocarbyl group.

Preferably, component (c) used to prepare the quaternary ammonium salt of the present invention is the reaction product of optionally substituted succinic acid or its anhydride having formula (A3) or formula (A4):

where R is hydrogen or an optionally substituted hydrocarbyl group. Preferably R ⁴ is an optionally substituted alkyl or alkenyl group.

In some embodiments, R is an optionally substituted C ₁ -C ₅₀₀ alkyl or alkenyl group, preferably a C ₂ -C ₁₀₀ alkyl or alkenyl group, preferably a C ₆ -C ₅₀ alkyl or alkenyl group, preferably a C ₈ -C ₄₀ alkyl or alkenyl group. a group, more preferably a C ₁₀ -C ₃₈ alkyl or alkenyl group, preferably a C ₁₆ -C ₃₆ alkyl or alkenyl group, preferably a C ₁₈ -C ₃₂ alkyl or alkenyl group.

R may be substituted with one or more groups selected from halogen (eg chlorine, fluorine or bromine), nitro, hydroxy, mercapto, sulfoxy, amino, nitrile, acyl, carboxy, alkyl (eg C ₁ -C ₄ alkyl), an alkoxy group (eg C ₁ -C ₄ alkoxy groups), amido, keto, sulfoxy and cyano groups.

Preferably R is an unsubstituted alkyl or alkenyl group. Substituted succinic acid or its anhydrides may suitably be prepared by reacting maleic anhydride with an alkene.

In some embodiments, the molecular weight R is 100 to 5000, preferably 300 to 4000, preferably 450 to 2500, such as 500 to 2000 or 600 to 1500.

In some embodiments, the substituted succinic acid or its anhydride may include a mixture of compounds containing R groups of various lengths. In such embodiments, any reference to the molecular weight of the R group refers to the number average molecular weight of the mixture.

In some embodiments, R is a polyisobutenyl group preferably having a number average molecular weight of 100 to 5000, more preferably 200 to 2000, more preferably 220 to 1300, such as 240 to 900.

In some embodiments, R is a polyisobutenyl group having a number average molecular weight of 400 to 700.

In some embodiments, R is a polyisobutenyl group having a number average molecular weight of 180 to 400.

In some embodiments, R is a polyisobutenyl group having a number average molecular weight of 800 to 1200.

In some embodiments, R is an alkyl or alkenyl group containing 6 to 40 carbon atoms, preferably 10 to 38 carbon atoms, more preferably 16 to 36 carbon atoms, more preferably 18 to 26 carbon atoms, such as 20 to 24 carbon atoms.

In some embodiments, R may be an internal olefin residue. In such embodiments, a compound having formula (A3) or (A4) is preferably obtained by reacting maleic acid with an olefin having an internal double bond arrangement.

In the context of the present invention, an internal olefin means any olefin containing primarily a non-alpha double bond, ie a beta or higher order olefin. Preferably, such materials are essentially all beta-olefins or higher order olefins, for example, contain less than 10 wt% alpha olefin, more preferably less than 5 wt%, or less than 2 wt%. Typical internal olefins include Neodene 1518IO available from Shell.

Sometimes internal olefins are referred to as isomerized olefins; they may be obtained from alpha-olefins by isomerization known in the art, or may be obtained from other sources. The fact that they are also referred to as internal olefins reflects that they need not be obtained by isomerization.

Component (c) is the reaction product of succinic acid or succinic anhydride having the formula (A3) or formula (A4) and an alcohol having the formula H-(OR ⁴ ) _n -OR ⁵ ; where R represents an alkyl or alkenyl group containing from 6 to 36 carbon atoms, or a polyisobutenyl group, the number average molecular weight of which is from 200 to 1300.

In some particularly preferred embodiments, component (c) is derived from succinic acid or succinic anhydride containing a C ₁₀ -C ₃₀ -, preferably C ₂₀ -C ₂₄ -alkyl or -alkenyl group.

Component (c) may have the formula (B1) or (B2):

Such a compound can be prepared by reacting hydrocarbyl-substituted succinic acid or the corresponding anhydride with an alcohol having the formula HO(R ⁴ O) _n R ⁵ .

Preferably the acid/anhydride and alcohol are reacted in a molar ratio of 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 2:1 to 1:2, e.g. 1.5 :1 to 1:1.5.

Most preferably, the acid/anhydride and alcohol are reacted in a molar ratio of approximately 1:1, for example from 1.2:1 to 1:1.2.

Preferably n is 0 to 30, more preferably 0 to 20, more preferably 1 to 16; R ⁴ is an alkylene group containing 1 to 12, preferably 1 to 6, more preferably 2 or 3 carbon atoms; and R ⁵ is hydrogen or C ₁ -C ₄₀ -, preferably C ₆ -C ₃₀ -, more preferably C ₁₀ -C ₂₀ -alkyl group; with the proviso that n is not 0 if R ⁵ is hydrogen.

R ⁵ is an optionally substituted hydrocarbyl group.

In some embodiments, n is 0, and the additive according to the invention can be obtained from an alcohol having the formula R ⁵ OH.

In such embodiments, R ⁵ is preferably an optionally substituted alkyl, alkenyl or aryl group, preferably having 1 to 60, more preferably 10 to 40 carbon atoms. Preferably R ⁵ is an optionally substituted alkyl group. In some embodiments, R ⁵ is a hydroxy-substituted alkyl group.

In some preferred embodiments, R ⁵ is an unsubstituted alkyl group. The alkyl group may be straight or branched. In some embodiments, R ⁵ is an optionally substituted alkyl group containing 4 to 40, preferably 6 to 30, more preferably 10 to 20 carbon atoms.

In some embodiments, n is 0 and component (c) is derived from a C ₆ -C ₃₆ -, preferably a C ₈ -C ₃₀ -, more preferably a C ₁₀ -C ₂₀ -alcohol, optionally substituted.

In one embodiment, component (c) is a tetradecanol ester.

Alcohols having the formula R ⁵ OH suitable for use in the invention include benzyl alcohol, tetradecanol, butanol, 2-butanol, isobutanol, octanol, 2-ethylhexanol, hexanol, cyclohexanol, cyclooctanol, 2-propylheptanol, 2-ethyl-1- butanol and isopropanol.

Alcohols having the formula R ⁵ OH suitable for use according to the invention are butanol and 2-ethylhexanol.

In some embodiments, n is not equal to 0, and the quaternary ammonium salt can preferably be obtained from an alcohol having the formula HO(R ⁴ O) _n R ⁵ .

R ⁵ is hydrogen or an optionally substituted hydrocarbyl group.

If R ⁵ is hydrogen, then component (c) is preferably an alkylene glycol or polyalkylene glycol ester.

If R ⁵ is not hydrogen, then component (c) can be obtained by reacting an optionally substituted dicarboxylic acid with an alkylene glycol or a polyalkylene glycol, and then reacting to form an ether, or a compound having the formula HO(R ⁴ O) _n R ⁵ , may be reacted with an optionally substituted dicarboxylic acid.

R ⁴ is an optionally substituted alkylene group.

In some embodiments, the alcohol having the formula H-(OR) _n -OH contains more than 2 hydroxyl groups and the R group is an alkylene group substituted with hydroxyl. Such a group may contain 1, 2 or more hydroxyl groups.

For example, in some embodiments, the alcohol H-(OR) _n -OH can be glycerol, pentaerythritol, or trimethylolpropane.

Preferably R ⁴ is an unsubstituted alkylene group.

Preferably R ⁴ is an optionally substituted alkylene group containing 1 to 50 carbon atoms, preferably 1 to 40 carbon atoms, more preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms , for example, 2 to 6 or 2 to 4 carbon atoms.

Preferably R ⁴ is an unsubstituted alkylene group containing 1 to 50 carbon atoms, preferably 1 to 20, more preferably 1 to 10, more preferably 2 to 6, eg 2 to 4 carbon atoms. R ⁴ may be straight or branched.

Preferably R ⁴ may be an ethylene, propylene, butylene, pentylene or hexylene group. If R ⁴ contains more than 2 carbon atoms, then any isomer may be present. Preferably R ⁴ is an ethylene or propylene group, most preferably a propylene group.

In some embodiments in which n is 1, R ⁴ may be a group having the formula (CH ₂ ) _x where x is 2 to 12, preferably 2 to 6.

In some embodiments in which n is 1, R ⁴ is a straight or branched alkylene group, and the alcohol is selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1, 4-butanediol, 1,6-hexanediol and neopentyl glycol.

In some preferred embodiments, R ⁴ is preferably CR ^a R ^b CR ^c R ^d and the polyol has the formula H-(OCR ^a R ^b CR ^c R ^d ) _n OH, where each of R ^a , R ^b , R ^c and R ^d is independently hydrogen or an optionally substituted alkyl group. Preferably, R ^a , R ^b , R ^c and R ^d are each independently selected from hydrogen or an optionally substituted alkyl group containing 1 to 20, preferably 1 to 12, more preferably 1 to 4, e.g. 1 to 2 atoms carbon.

Preferably, R ^a , R ^b , R ^c and R ^d are each independently selected from hydrogen and an unsubstituted alkyl group, preferably containing 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, more preferably 1 to 4 atoms, for example, 1 or 2 carbon atoms. Preferably at least two of R ^a , R ^b , R ^c and R ^d are hydrogen atoms, more preferably at least three of R ^a , R ^b , R ^c and R ^d are hydrogen atoms.

In some embodiments, R ^a , R ^b , R ^c and R ^d are all hydrogen atoms and R is an ethylene group, CH ₂ CH ₂ .

In some embodiments, three of R ^a , R ^b , R ^c and R ^d are hydrogen atoms and the remaining radical is an unsubstituted alkyl group containing 1 to 12, preferably 1 to 4, more preferably 1 to 2 and most preferably 1 carbon atom.

In some embodiments, the polybasic alcohols used to prepare component (c) are derived from epoxides, preferably terminal epoxides.

R ⁴ may include a mixture of isomers. For example, if R ⁴ is propylene, then the polyol chain may include —CH ₂ CH(CH ₃ )— and —CH(CH ₃ )CH ₂ — moieties in any order.

R ⁴ may include a mixture of different groups, for example ethylene, propylene or butylene units. In such embodiments, units of block copolymers are preferred.

R ⁴ preferably represents an ethylene, propylene or butylene group. R ⁴ may be an n-propylene or n-butylene group, or an isopropylene or isobutylene group. For example, R ⁴ may be -CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )-, -CH ₂ C(CH ₃ ) ₂ , -CH(CH ₃ )CH(CH ₃ )- or -CH ₂ CH (CH ₂ CH ₃ ) -.

Preferably R ⁴ is ethylene or propylene. More preferably R ⁴ is -CH ₂ CH ₂ - or -CH(CH ₃ )CH ₂ -. Most preferably R ⁴ is -CH(CH ₃ )CH ₂ -.

In some embodiments, n is at least 1. Preferably n is 1 to 100, preferably 1 to 50, more preferably 1 to 30, more preferably 1 to 24, more preferably 1 to 20, more preferably 1 to 16 , preferably from 1 to 14.

In some embodiments, n is 4 to 10, such as 6 to 8.

In some embodiments, n is 1 to 6, preferably 2 to 5, such as 3 or 4.

In some embodiments, n is 8 to 16, such as 11 to 14.

In some embodiments, component (c) is derived from a polybasic alcohol having the formula HO(R ⁴ O)H or an ether of such an alcohol having the formula HO(R ⁴ O) _n R ⁵ .

Preferably the acid/anhydride and alcohol are reacted in a molar ratio of 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 2:1 to 1:2, e.g. 1.5 :1 to 1:1.5.

Most preferably, the acid/anhydride and alcohol are reacted in a molar ratio of approximately 1:1, eg 1.2:1 to 1:1.2.

In some embodiments, the polybasic alcohol may be a polypropylene glycol having a number average molecular weight of 425.

In some embodiments, the polyol may be selected from triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol.

In some embodiments, the polyol is selected from ethylene glycol, propylene glycol, and their oligomers or polymers.

In some embodiments, the polyol may be a polypropylene glycol having a number average molecular weight of 725 or more.

One of skill in the art will appreciate that commercial sources of alcohols having the formula H-(OR ⁴ ) _n -OH often contain mixtures of compounds in which, for example, n can be from 6 to 10.

Commercial sources of substituted succinic acids and anhydrides may also contain mixtures of compounds, for example, including various compounds having substituents containing from 20 to 24 carbon atoms.

In some preferred embodiments, R ⁵ is hydrogen.

In some embodiments, R ⁵ is hydrogen, n is 1, and R is a straight or branched alkylene group. In such embodiments, the alcohol having the formula HO(R ⁴ O) _n R ⁵ is selected from ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1, 6-hexanediol and neopentyl glycol.

In some embodiments, R ⁵ is not hydrogen, n is not 0, and the additive of the invention is made from a polyol ether, such as polyethylene glycol ether, polypropylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, or tripropylene glycol.

In some embodiments in which n is not O, R ⁵ is an optionally substituted alkyl, alkenyl or aryl group, preferably an optionally substituted alkyl or alkenyl group. Preferably R ⁵ contains 4 to 50 carbon atoms, more preferably 4 to 40 carbon atoms, more preferably 10 to 30 carbon atoms. R ⁵ may be a straight or branched group. Preferably R ⁵ is straight chain.

In some embodiments, R ⁵ is a substituted alkyl or alkenyl group, preferably a substituted alkyl group. Preferably the substituents are hydroxy groups and ester groups.

Preferably R ⁵ is an unsubstituted alkyl or alkenyl group. Preferably R ⁵ is an alkyl group, preferably an unsubstituted alkyl group.

Preferably R ⁵ is selected from hydrogen and an alkyl group containing 1 to 40, preferably 6 to 30, more preferably 10 to 20 carbon atoms.

In some embodiments, n is 10 to 40, preferably 15 to 30, more preferably 20 to 25; R ² is ethylene or propylene, most preferably propylene; and R ⁵ is a C ₆ -C ₃₀ -, preferably a C ₁₀ -C ₂₀ -alkyl group.

In some embodiments, component (c) is the reaction product of an optionally substituted polycarboxylic acid or anhydride thereof, where the acid is selected from pyromellitic acid, malonic acid, sebacic acid, and succinic acid, and an alcohol having the formula HO(R ⁴ O) _n R ⁵ , selected from:

- ethylene glycol, propylene glycol and their oligomers or polymers; alkanediols containing from 1 to 12, preferably from 3 to 6 carbon atoms; sugar alcohols or their ethers; and

- alkanols containing from 1 to 30, preferably from 6 to 25 carbon atoms.

In some embodiments, component (c) is the reaction product of an optionally substituted polycarboxylic acid or anhydride thereof, where the acid is selected from pyromellitic acid and succinic acid, and an alcohol having the formula HO(R ⁴ O) _n R ⁵ , where the alcohol is selected from:

- ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, trehalose, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol , polyethylene glycol or polypropylene glycol, the number average molecular weight of which is from 300 to 1200, or its C ₁ -C ₃₀ simple ether; and

- benzyl alcohol, tetradecanol, butanol, 2-butanol, isobutanol, octanol, 2-ethylhexanol, hexanol, cyclohexanol, cyclooctanol, 2-propylheptanol, 2-ethyl-1-butanol and isopropanol.

In some embodiments, component (c) is the reaction product of succinic acid or succinic anhydride having the formula (A3) or formula (A4) and an alcohol having the formula HO(R ⁴ O) _n R ⁵ where R ² is an alkyl or alkenyl group having 6 to 36 carbon atoms, or a polyisobutenyl group having a number average molecular weight of 200 to 1300, wherein the alcohol having the formula HO(R ⁴ O) _n R ⁵ is selected from:

- ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, trehalose, sorbitol, glycerol, pentaerythritol, trimethylolpropane, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol , 1,6-hexanediol, neopentyl glycol and polyethylene or polypropylene glycol, the number average molecular weight of which is from 300 to 1200, or its C ₆ -C ₂₄ simple ether; and

- benzyl alcohol, tetradecanol, butanol, 2-butanol, isobutanol, octanol, 2-ethylhexanol, hexanol, cyclohexanol, cyclooctanol, 2-propylheptanol, 2-ethyl-1-butanol and isopropanol.

In some embodiments, component (c) used to prepare the quaternary ammonium salt of the present invention is the reaction product of succinic acid or its anhydride having an alkyl or alkenyl substituent containing from 6 to 36 carbon atoms and polypropylene glycol (or its simple C ₁ -C ₃₆ -alkyl ether), the number average molecular weight of which is from 300 to 800.

In some embodiments, component (c) is the reaction product of succinic acid or its anhydride having an alkyl or alkenyl substituent containing from 6 to 36 carbon atoms and a polybasic alcohol (or its simple C ₁ -C ₃₆ alkyl ether) selected from ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and tetrapropylene glycol.

In some embodiments, component (c) is the reaction product of succinic acid or its anhydride having an alkyl or alkenyl substituent containing from 6 to 36 carbon atoms and a polybasic alcohol (or its simple C ₁ -C ₃₆ alkyl ether) selected from glycerin, pentaerythritol and trimethylolpropane.

In some embodiments, component (c) is the reaction product of succinic acid or succinic anhydride containing C ₆ -C ₃₆ -, preferably C ₁₀ -C ₃₀ -, more preferably C ₂₀ -C ₂₄ -alkyl or alkenyl substituent, and polyethylene glycol or polypropylene glycol (or its simple C ₁ -C ₃₆ alkyl ether) containing from 4 to 16, preferably from 6 to 8 alkoxy groups.

In some embodiments, component (c) is the reaction product of succinic acid or succinic anhydride containing a C ₁₀ -C ₃₀ -, preferably C ₂₀ -C ₂₄ -alkyl or alkenyl substituent, and an alcohol having the formula R ⁵ OH, where R ⁵ is a C ₆ -C ₃₀ -, preferably a C ₁₀ -C ₂₀ -alkyl group.

In some embodiments, component (c) is the reaction product of succinic acid or its anhydride having an alkyl or alkenyl substituent containing from 6 to 36 carbon atoms and polyethylene glycol (or its simple C ₁ -C ₃₆ alkyl ether), number average molecular the mass of which is from 200 to 800.

In some embodiments, component (c) is the reaction product of polyisobutenyl-substituted succinic acid or polyisobutenyl-substituted succinic anhydride containing a PIB substituent (i.e. polyisobutenyl, from the English polyisobutenyl), the number average molecular weight of which is from 200 to 2500, and polypropylene glycol (or its simple C ₁ -C ₃₆ -alkyl ether), the number average molecular weight of which is from 300 to 800.

In some embodiments, component (c) is the reaction product of polyisobutenyl-substituted succinic acid or polyisobutenyl-substituted succinic anhydride containing a PIB substituent having a number average molecular weight of 200 to 2500 and a polybasic alcohol (or its simple C ₁ -C ₃₆ alkyl ether) selected from ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and tetrapropylene glycol.

In some embodiments, component (c) is the reaction product of polyisobutenyl-substituted succinic acid or polyisobutenyl-substituted succinic anhydride containing a PIB substituent having a number average molecular weight of 200 to 2500 and a polybasic alcohol (or its simple C ₁ -C ₃₆ alkyl ether) selected from glycerol, pentaerythritol and trimethylolpropane.

In some embodiments, component (c) is the reaction product of polyisobutenyl-substituted succinic acid or polyisobutenyl-substituted succinic anhydride containing a PIB substituent having a number average molecular weight of 200 to 2500 and polyethylene glycol (or its C ₁ -C ₃₆ alkyl ether ), the number average molecular weight of which is from 200 to 800.

In some embodiments, component (c) is the reaction product of polyisobutenyl-substituted succinic acid or polyisobutenyl-substituted succinic anhydride containing a PIB substituent having a number average molecular weight of 200 to 2500 with polyethylene glycol or polypropylene glycol (or the corresponding simple C ₁ -C ₃₆ alkyl ether) containing from 4 to 16, preferably from 6 to 8 alkoxy groups.

To avoid misunderstanding, it should be noted that component (c) may include a mixture of compounds. The compounds that may be contained include mixtures obtained by reacting a mixture of various polyhydric alcohols with a polycarboxylic acid and/or mixtures obtained by reacting a mixture of polyhydric alcohols with a mixture of polycarboxylic acids and/or compounds obtained by reacting a mixture of polyhydric alcohols with a mixture of carboxylic acids . Such mixtures may also include mixtures of initially pure, fully formed ester compounds.

In one particularly preferred embodiment, component (c) is the reaction product of succinic acid or succinic anhydride containing a C ₂₀ -C ₂₄ alkyl or alkenyl substituent and an alcohol selected from polypropylene glycol, the number average molecular weight of which is from 300 to 800, 2-ethylhexanol and butanol.

In preferred embodiments, the quaternary ammonium compound of the present invention is the product of the reaction:

(a) a tertiary amine having the formula R ¹ R ² R ³ N, where each of R ¹ , R ² and R ³ independently represents an optionally substituted alkyl group containing 1 to 12 carbon atoms;

(b) an epoxide selected from styrene oxide, ethylene oxide, propylene oxide, butylene oxide, epoxyhexane, octenoxide, stilbene oxide, 2-ethylhexylglycidyl ether, 1,2-epoxydecane, and other alkyl and alkenyl epoxides containing from 2 to 50 carbon atoms; and

(c) a compound having the formula HOOCXCOO-(R ⁴ O) _n -R ⁵ where X is CH ₂ CHR or CHRCH ₂ in which R is an optionally substituted hydrocarbyl group; and

n is greater than 1, R ⁴ is an ethylene or propylene group, and R ⁵ is hydrogen; or

n is 0 or and R ⁵ is a C ₁ -C ₂₀ alkyl group.

In more preferred embodiments, the quaternary ammonium compound of the present invention is the product of the reaction:

(a) a tertiary amine having the formula R ¹ R ² R ³ N, where each of R ¹ , R ² and R ³ independently represents an alkyl or hydroxyalkyl group containing from 1 to 6 carbon atoms;

(b) an epoxide selected from propylene oxide, butylene oxide and 2-ethylhexylglycidyl ether; and

(c) a compound having the formula HOOCXCOO-(R ⁴ O) _n -R ⁵ which is the reaction product of succinic acid or succinic anhydride containing a C ₂₀ -C ₂₄ alkyl or alkenyl substituent and an alcohol selected from polypropylene glycol, number average the molecular weight of which is from 300 to 800, 2-ethylhexanol and butanol.

The third aspect of the present invention relates to a composition comprising a quaternary ammonium compound having the formula (I):

where each of R ⁰ , R ¹ , R ² and R ³ independently represents an optionally substituted hydrocarbyl group, X represents a connecting group, R ⁴ represents an optionally substituted alkylene group, R ⁵ represents hydrogen or an optionally substituted alkyl, alkenyl or aryl group group, and n is 0 or a positive integer, provided that n is not 0 if R ⁵ is hydrogen.

Preferred features of the third aspect are disclosed in the description of the first and second aspects.

In some embodiments, the composition according to the third aspect is an additive composition comprising a quaternary ammonium salt according to the first aspect and a diluent or carrier.

The additive composition may be a lubricating oil additive composition.

Preferably the additive composition is an additive composition for a fuel composition, preferably a diesel fuel composition.

The quaternary ammonium compound is preferably present in the additive composition in an amount ranging from 1 to 99% by weight, for example, from 1 to 75% by weight.

The additive composition may include a mixture of two or more Quaternary ammonium compounds according to the present invention. In such embodiments, the above amounts preferably indicate the total amount of all such compounds present in the composition.

The additive composition may include one or more additional additives. They may be selected from antioxidants, dispersing agents, detergents, metal deactivating compounds, wax anti-settling agents, cold flow improvers, cetane improvers, anti-haze agents, stabilizers, demulsifiers, defoamers, corrosion inhibitors. , lubricity additives, dyes, markers, flame enhancers, metal deactivators, odor masking agents, friction modifiers and conduction agents.

In some preferred embodiments, the additive composition includes one or more additional nitrogen-containing detergent additives.

A third aspect of the present invention may relate to a fuel composition or lubricating oil composition comprising a quaternary ammonium salt according to the first aspect.

Some embodiments of the present invention relate to a lubricating composition comprising an oil having a viscosity suitable for a lubricating oil and, as an additive, a quaternary ammonium salt having the formula (I):

where each of R ⁰ , R ¹ , R ² and R ³ independently represents an optionally substituted hydrocarbyl group, X represents a connecting group, R ⁴ represents an optionally substituted alkylene group, R ⁵ represents hydrogen or an optionally substituted alkyl, alkenyl or aryl group group, and n is 0 or a positive integer, provided that n is not 0 if R ⁵ is hydrogen.

In some preferred embodiments, the third aspect of the present invention relates to a fuel composition comprising as an additive a quaternary ammonium salt having formula (I):

where each of R ⁰ , R ¹ , R ² and R ³ independently represents an optionally substituted hydrocarbyl group, X represents a connecting group, R ⁴ represents an optionally substituted alkylene group, R ⁵ represents hydrogen or an optionally substituted alkyl, alkenyl or aryl group group, and n is 0 or a positive integer, provided that n is not 0 if R ⁵ is hydrogen.

The present invention may further provide a method for producing a fuel composition, which includes obtaining a quaternary ammonium salt according to the first aspect, and mixing the quaternary ammonium salt with fuel.

The fuel composition according to the present invention is preferably a diesel fuel composition.

Preferably, the quaternary ammonium salt additive is present in the diesel fuel composition in an amount of at least 0.1 ppm, preferably at least 1 ppm, more preferably at least 5 ppm, more preferably at least 10 ppm, preferably at least 20 ppm, eg at least 30 ppm or at least 50 ppm.

Preferably, the quaternary ammonium salt additive is present in the diesel fuel composition in an amount of less than 10,000 ppm, preferably less than 1,000 ppm, more preferably less than 500 ppm, more preferably less than 300 ppm, e.g., less than 250 ppm. million.

In some embodiments, the quaternary ammonium salt additive is present in the diesel fuel composition in an amount preferably less than 200 ppm, such as less than 150 ppm.

Preferably, the quaternary ammonium salt additive is present in the diesel fuel in an amount of 80 to 130 ppm.

Any reference to parts per million in this work refers to mass parts per million.

The diesel fuel compositions of the present invention may include a mixture of two or more quaternary ammonium salt additives. In such embodiments, the above amounts refer to the total amount of all such additives present in the composition.

The use of mixtures may be advantageous due to the availability of starting materials, or a particular mixture may be deliberately chosen to achieve a certain beneficial effect. For example, the use of a particular blend may facilitate process operations, improve overall performance, or have a synergistic effect on performance.

Any reference herein to "additives" or "additives according to the invention" includes exemplary embodiments in which one additive compound is present and exemplary embodiments in which two or more additive compounds are present. Those embodiments in which two or more compounds are present may include mixtures obtained from a mixture of starting materials used to prepare additive compounds (for example, mixtures of polybasic alcohols and/or mixtures of polycarboxylic acids and/or mixtures of tertiary amines and/or mixtures quaternizing agents). Alternatively and/or additionally, two or more preformed compounds of formula (I) may be added to the composition, eg, fuel or lubricant composition.

Quaternary ammonium salt additives can be added to diesel fuel at any suitable stage in the value chain. For example, additives may be added to fuel at a refinery, at a distribution terminal site, or after the fuel has been transported from a distribution terminal. If the additive is added to the fuel after it has been transported from the distribution terminal, this is referred to as post-sales application of the additive. Post-market use includes such circumstances as adding fuel from a delivery tanker directly to a customer-owned bulk container or directly to an end-user tanker truck. Aftermarket applications may include the supply of a fuel additive in small bottles suitable for direct addition to fuel storage tanks or tank trucks.

By "diesel fuel" we include any fuel suitable for driving both road vehicle diesel engines and other types of diesel engines. This fuel includes, without limitation, fuels referred to as diesel fuel, marine diesel fuel, heavy fuel oil, industrial fuel oil, etc.

The diesel fuel composition of the present invention may include a petroleum based fuel oil, in particular a middle distillate fuel oil. Boiling points of distillate fuel oils usually lie in the range from 110°C to 500°C, for example, from 150°C to 400°C. The diesel fuel may include atmospheric distillate or vacuum distillate, cracked gas oil, or a mixture of any proportions of straight run products and refinery streams such as distillates from thermal and/or catalytic cracking and hydrocracking.

The diesel fuel composition may include non-renewable Fischer-Tropsch fuels such as fuels referred to as GTL (gas-to-liquid) fuels, CTL (i.e. gas-to-liquid) fuels. e. obtained by the technology of processing "coal to liquid", eng. coal-to-liquid) and OTL fuel (i.e. obtained by the technology of processing "oil sands to liquid", eng. oil sands-to-liquid).

The diesel fuel composition may include a renewable fuel such as a biofuel composition or a biodiesel composition.

The diesel fuel composition may include first generation biodiesel. First generation biodiesel contains esters from, for example, vegetable oils, animal fats and used cooking oils. This form of biodiesel can be obtained by transesterification of oils such as rapeseed oil, soybean oil, canola oil, safflower oil, palm oil, corn oil, peanut oil, cottonseed oil, tallow, coconut oil, laxative nut oil (jatropha oil) , sunflower oil, used cooking oils, hydrogenated vegetable oils, or any mixtures of these oils, by the action of an alcohol, usually a monoalcohol, usually in the presence of a catalyst.

The diesel fuel composition may include second generation biodiesel. Second generation biodiesel is derived from renewable sources such as vegetable oils and animal fats and processed, often in a refinery and often using hydroprocessing such as the H-Bio process developed by Petrobras. Second generation biodiesel can be similar in properties and quality to petroleum-based fuel oil streams, and as an example, renewable diesel derived from vegetable oils, animal fats, etc., which ConocoPhillips markets under the name Renewable Diesel , and Neste - under the name NExBTL.

The diesel fuel composition may include third generation biodiesel. To obtain biodiesel fuel of the third generation, including the fuel called BTL fuel (i.e. obtained by technology "biomass-to-fuel", English biomass-to-liquid), gasification and the Fischer-Tropsch method are used. Third generation biodiesel is not too different from some types of second generation biodiesel, but the whole plant (biomass) is processed to produce it, which greatly expands the resource base.

The diesel fuel composition may contain mixtures of any or all of the above diesel fuel compositions.

In some embodiments, the diesel fuel composition may be a diesel fuel blend including biodiesel. In such mixtures, the amount of biodiesel fuel can be, 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%, up to 30%, up to 40%, up to 50%, up to 60%, up to 70%, up to 80%, up to 90%, up to 95% or up to 99%.

In some embodiments, the fuel composition may include pure biodiesel.

In some preferred embodiments, the fuel composition comprises at least 5% by weight biodiesel.

In some embodiments, the fuel composition may include pure GTL fuel.

In some embodiments, the diesel fuel composition may include a secondary fuel such as ethanol. However, the diesel fuel composition preferably does not contain ethanol.

The diesel fuel composition used according to the present invention may include a relatively high sulfur content, for example, more than 0.05% wt., such as 0.1% or 0.2%.

However, in preferred embodiments, the maximum sulfur content of the diesel fuel is 0.05% by weight, more preferably 0.035% by weight, in particular not more than 0.015%. Even lower sulfur fuels are also suitable, such as fuels containing less than 50 wt. ppm sulfur, preferably less than 20 ppm, for example 10 ppm or less.

The composition of diesel fuel according to the present invention preferably includes at least 5% of the mass. biodiesel and less than 50 ppm sulfur.

The quaternary ammonium salt additives of the present invention added to fuel and lubricant compositions have been found to be effective in controlling deposits.

The present invention can provide the use of a quaternary ammonium compound according to the first aspect as an additive for fuel compositions or lubricating oil compositions.

The present invention can provide the use of the quaternary ammonium compound according to the first aspect as a deposit control additive added to fuel or lubricating oil compositions.

The present invention can provide the use of a quaternary ammonium compound according to the first aspect as a deposit control additive added to lubricating oil compositions.

The present invention can provide the use of a quaternary ammonium compound according to the first aspect as a deposit control additive added to fuel compositions.

The present invention can provide the use of the quaternary ammonium compound according to the first aspect as a deposit control additive added to diesel fuel compositions.

The fourth aspect of the present invention relates to the use of a quaternary ammonium compound having the formula (I):

where each of R ⁰ , R ¹ , R ² and R ³ individually represents an optionally substituted alkyl, alkenyl or aryl group, X represents a connecting group, R ⁴ represents an optionally substituted alkylene group, R ⁵ represents hydrogen or an optionally substituted alkyl , an alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 if R ⁵ is hydrogen, as an additive for a fuel composition or a lubricant composition.

The preferred features of the fourth aspect are disclosed in connection with the first, second and third aspects.

The use according to the fourth aspect preferably refers to the use of the quaternary ammonium salt as a fuel additive, preferably a diesel fuel additive.

Preferably, the use according to the fourth aspect refers to the use of the quaternary ammonium salt according to the first aspect as a detergent additive.

A fourth aspect of the present invention may provide the use of a quaternary ammonium compound of formula (I) to improve engine performance. Application is properly achieved when a composition containing a quaternary ammonium compound is burned in an engine.

Preferably the engine is a diesel engine.

The fifth aspect of the present invention relates to a method for improving engine performance, wherein the method includes combustion in the engine of a fuel composition comprising a quaternary ammonium compound having the formula (I) as an additive:

where each of R ⁰ , R ¹ , R ² and R ³ independently represents an optionally substituted hydrocarbyl group, X represents a connecting group, R ⁴ represents an optionally substituted alkylene group, R ⁵ represents hydrogen or an optionally substituted alkyl, alkenyl or aryl group group, and n is 0 or a positive integer, provided that n is not 0 if R ⁵ is hydrogen.

Preferred features of the fifth aspect of the invention are disclosed in connection with the first, second, third and fourth aspects.

The method according to the fifth aspect preferably includes combustion in an engine of the composition according to the third aspect.

The fifth aspect of the invention relates to a method for improving engine performance.

Preferably the engine is a diesel engine.

Most preferably, the engine is a direct injection diesel engine.

The present invention relates to improving the performance of diesel engines by burning diesel fuel compositions comprising a quaternary ammonium salt additive.

Preferably, improvement in engine performance is achieved by controlling deposits in the engine.

In preferred embodiments, the fifth aspect of the present invention relates to a method for controlling deposits in an engine, preferably a diesel engine.

The method can be carried out by combustion in the engine of the additive composition based on Quaternary ammonium salt, acting as a detergent additive.

Thus, the present invention can provide a method for controlling deposits in a diesel engine, wherein the method includes combustion in the engine of a fuel composition comprising a quaternary ammonium salt as an additive according to the first aspect.

Preferably, the use in the engine according to the fourth aspect improves the performance of the engine, preferably a diesel engine. This improvement in performance, for example, can be achieved by controlling deposits in the engine.

A fourth aspect of the present invention relates to the use of a quaternary ammonium salt additive as a detergent additive.

Mention in this work of improving performance and/or controlling deposits may refer to the fourth and/or fifth aspects of the invention.

The quaternary ammonium salt additives of the present invention have been found to be particularly beneficial in modern diesel engines incorporating a high pressure fuel system. Some features of engines of this type have been discussed above.

Preferably, the present invention provides for deposit control and/or performance enhancement of a diesel engine incorporating a high pressure fuel system. Preferably, the pressure in the diesel engine is greater than 1350 bar (1.35×10 ⁸ Pa). The pressure in a diesel engine can be up to 2000 bar (2×10 ⁸ Pa) or more.

Two non-limiting examples of such high pressure fuel systems are: a common injection system in which the fuel is compressed by a high pressure pump supplying fuel to the fuel injection valves through a common injection pipe, and a unit injector system in which the high pressure pump pressure and injection valve are integrated in one unit, which makes it possible to achieve the highest possible injection pressures in excess of 2000 bar (2×10 ⁸ Pa). In both systems, when the fuel is compressed, it heats up, often to temperatures of about 100° C. or more.

In systems with a common discharge pipeline, the fuel is stored at high pressure in a central storage pipeline or separate storage tanks before being fed to the injectors. Often, some of the heated fuel is returned to the low pressure portion of the fuel system or returned to the fuel tank. To achieve high injection pressures in a unit injector system, the fuel is compressed inside the injector. This in turn raises the temperature of the fuel.

In both systems, before injection, the fuel is in the nozzle body, where it is additionally heated by the combustion chamber. The fuel temperature at the nozzle tip can reach 250-350°C.

Thus, before injection, the fuel is compressed to pressures ranging from 1350 bar (1.35×10 ⁸ Pa) to more than 2000 bar (2×10 ⁸ Pa), while fuel temperatures reach from about 100°C to 350 °C, and sometimes the fuel is recycled back into the fuel system, thus increasing the residence time of the fuel under the described conditions.

A common problem with diesel engines is clogging of injectors, in particular the injector body and injector nozzle. The fuel filter may also be clogged. Injector nozzle clogging occurs when the nozzle becomes clogged with deposits formed by diesel fuel. Clogged fuel filters may be due to fuel being recirculated back to the fuel tank. Deposit formation intensifies as the fuel decomposes. The deposits can form as carbonaceous coke residues, varnish deposits, or sticky or tarry residues. Diesel fuels become more and more unstable as they are heated, in particular under pressure. Thus, increased fuel decomposition can occur in diesel engines with high pressure fuel systems. In recent years, in order to meet the requirements for reducing emissions into the atmosphere, the design of injection systems has been constantly updated. This leads to more complex nozzle designs and low resistance to deposit formation.

Injector clogging can occur with any type of diesel fuel. However, some fuels may be particularly prone to fouling, or fouling may occur more rapidly when using these fuels. For example, increased deposit formation can occur when using fuels containing biodiesel and fuels containing metal compounds.

With complete or partial clogging of the injectors, the fuel supply is reduced, and the mixing of fuel with air deteriorates. Over time, this leads to a decrease in engine power, an increase in exhaust emissions into the atmosphere and a decrease in fuel economy.

It is known that deposits form in the spray channels of the nozzle, which leads to a decrease in flow and a decrease in power. The smaller the size of the nozzle nozzle opening, the higher the relative influence of deposit buildup. It is also known that deposits form at the nozzle tip. Such deposits adversely affect the fuel atomization pattern, resulting in reduced combustion efficiency and increased emissions to the atmosphere, as well as increased fuel consumption.

In addition to such "exterior" deposits at the nozzle orifice and nozzle tip that impede fuel flow and cause power loss, deposits can form inside the injector body, causing additional problems. These deposits can be called internal diesel injector deposits (abbreviated as VOFD, from the English internal diesel injector deposit, abbreviated as IDID). WOFDs are additionally formed inside the nozzle on important moving parts. They can impede the movement of such parts, negatively affecting the injection timing and the amount of fuel injected. Since modern diesel engines must operate with very high precision, these deposits can seriously degrade performance.

The formation of VOFD causes a number of problems, including reduced power and reduced fuel economy due to less than optimal dosing and combustion of fuel. Initially, the engine may experience cold start problems and/or the engine may run hard. The formation of such deposits can also lead to more serious clogging of the nozzles. This occurs if the deposits formed impede the movement of the nozzle parts, causing the nozzle to stop working. Clogging of some or all of the injectors can lead to a complete engine stop.

Recently, the CEC introduced the Diesel Engine Injector Injector Deposit Evaluation test, CEC F-110-16, which distinguishes between fuels with different HFO formation properties in direct injection common rail diesel engines.

As noted above, the problem of injector clogging is more likely to occur with fuel compositions that include metal compounds. Various metal compounds may be present in fuel compositions. They may result from fuel contamination during production, storage, transport or use, or from contamination of fuel additives. Metal compounds can also be intentionally added to the fuel. For example, transition metals are sometimes added to fuels as fuel-borne catalysts (fuel catalysts), for example, to improve the performance of diesel particulate filters (diesel particulate filters).

Jamming (blocking) of injectors can occur as a result of the reaction of metal or ammonium compounds, in particular sodium compounds, with compounds containing carboxyl groups in the fuel.

It is believed that the main cause of injector sticking is sodium-containing contaminants contained in diesel fuel and the carboxylate salts formed from them.

In some embodiments, the diesel fuel compositions used according to the present invention include sodium and/or calcium. Preferably the compositions include sodium. The total amount of sodium and/or calcium in the composition is usually from 0.01 to 50 ppm, preferably from 0.05 to 5 ppm, more preferably from 0.1 to 2 ppm, for example, from 0.1 to 1 ppm.

Contaminants can also be other metal-containing compounds, for example, compounds that enter the fuel as a result of the corrosive action of acidic compounds found in fuel or lubricants on metal surfaces and surfaces containing metal oxides. The use of a fuel such as diesel fuel involves the constant contact of the fuel with metal surfaces, such as in vehicle fuel supply systems, fuel tanks, fuel transport vehicles, and the like. Typically, metal contaminants may include transition metals such as zinc, iron and copper, Group I or Group II metals, and other metals such as lead.

The presence of metal-containing compounds can cause deposits to form on fuel filters and/or external parts of injectors, including deposits on the injector tip and/or deposits in the nozzle.

In addition to the introduction of metal-containing particles into diesel fuel as a result of its contamination, in some cases, metal-containing compounds can be intentionally added to the fuel. For example, as is known in the art, metal-containing fuel catalysts can be added to the fuel to aid in the regeneration of soot traps. The presence of such catalysts can also cause injector plugging when the appropriate fuel is supplied to a diesel engine incorporating a high pressure fuel system.

Depending on the source, the metal-containing contamination may be in the form of an insoluble powder or soluble compounds or complexes. Metal-containing fuel catalysts are often soluble compounds or complexes or colloidal particles.

In some embodiments, diesel fuel may contain metal-containing compounds, including a fuel catalyst. Preferably, the fuel catalyst comprises one or more metals selected from iron, cerium, platinum, manganese, Group I and Group II metals such as calcium and strontium. Most preferably, the fuel catalyst comprises a metal selected from iron and cerium.

In some embodiments, diesel fuel may include a metal-containing compound, including zinc. Zinc may be present in an amount of 0.01 to 50 ppm, preferably 0.05 to 5 ppm, more preferably 0.1 to 1.5 ppm.

Typically, the total amount of all metal-containing compounds in diesel fuel, expressed as the total weight of the metal contained in the compounds, is from 0.1 to 50 wt. ppm, for example, from 0.1 to 20 ppm, preferably from 0.1 to 10 wt. parts per million by weight of diesel fuel.

It would be useful to provide a diesel fuel composition that prevents or reduces the formation of deposits in a diesel engine. In some embodiments, such deposits may include "outer" deposits on nozzles, such as deposits in and around the nozzle opening and at the nozzle tip. In some preferred embodiments, deposits include "internal" deposits on the injector or VOFD. It can be said that the created fuel compositions provide the function of "maintaining cleanliness" i.e. they prevent or slow down the formation of blockages. It is also desirable to provide a diesel fuel composition that facilitates the removal of these types of deposits. When such a fuel composition is burned in a diesel engine, deposits are removed from engine parts, thus leading to a "cleaning" of an already contaminated engine.

As with the "keep clean" property, "cleaning" a fouled engine can provide significant benefits. For example, improved cleaning may result in increased power and/or improved fuel economy. In addition, the removal of deposits from the engine, in particular from the injectors, can increase the time interval between maintenance or replacement of the injectors, thus reducing maintenance costs.

Although injector deposits are a significant problem in modern diesel engines equipped with high pressure fuel systems for the reasons outlined above, it is desirable to provide a diesel fuel composition that also provides effective cleaning action in older conventional diesel engines. so that the same fuel supplied to the pumps can be used to run all types of engines.

It is also desirable that the fuel compositions provide reduced clogging of vehicle fuel filters. It would be useful to provide compositions that prevent or retard the formation of deposits on fuel filters, i. e. providing a "keep clean" function. It would be useful to provide compositions that aid in the removal of existing deposits from fuel filters, ie. providing the function of "cleaning". Particularly useful would be compositions that combine these two functions.

The method of the present invention is particularly effective in controlling deposits in a modern diesel engine equipped with a high pressure fuel system.

Such diesel engines may have a number of characteristics.

These engines are typically equipped with fuel injection equipment that meets or exceeds Euro 5 emissions requirements or equivalent US or other national legislation.

Such engines are typically provided with fuel injectors having a plurality of through passages, where each passage has an inlet and outlet portion.

Characteristic of these engines may be through channels that narrow so that the diameter of the spray inlet is greater than the diameter of the outlet of the channel.

Typical of such modern engines may be through passages in which the outlet diameter is less than 500 microns, preferably less than 200 microns, more preferably less than 150 microns, more preferably less than 100 microns, most preferably less than 80 microns or less.

Typical for such modern engines may be through channels in which the edge of the inlet is rounded.

Typical of such modern engines may be injectors having more than one through passage, preferably more than 2 through passages, preferably more than 4 through passages, for example 6 or more through passages.

Typical for such modern engines can be operating temperatures at the nozzle tip boundary exceeding 250°C.

Such modern engines may be characterized by the presence of a fuel injection system that provides a fuel pressure in excess of 1350 bar (1.35⋅10 ⁸ Pa), preferably in excess of 1500 bar (1.5⋅10 ⁸ Pa), more preferably in excess of 2000 bar (2⋅ 10 ⁸ Pa). Preferably, the diesel engine has a fuel injection system that includes a common rail injection system.

The application of the method according to the present invention preferably allows you to fight deposits in an engine having one or more of the characteristics discussed above.

The use of the present invention preferably improves engine performance. The improvement in engine performance is preferably achieved by reducing engine deposits.

The first aspect of the present invention preferably relates to a method for controlling deposits in a diesel engine. Deposit control may include the reduction or prevention of deposits in an engine compared to an engine running on a fuel without the appropriate additives. This method can be seen as providing a "keep clean" characteristic.

Deposit control may include the removal of existing deposits in the engine. This can be seen as a "clearing" characteristic.

In particularly preferred embodiments, the method according to the fifth aspect and the use according to the fourth aspect of the present invention may be implemented to provide "clean" and "clean" characteristics.

As mentioned above, deposits can form in various areas of a diesel engine, such as a modern diesel engine.

The present invention is particularly suitable for preventing or reducing or removing internal deposits in the injectors of engines operating at high pressures and temperatures with the possibility of fuel recirculation, where the injectors have many small channels (holes) through which the fuel is directed to the engine. The present invention can be applied to engines of high power vehicles and passenger vehicles. The application of the present invention may be useful, for example, for passenger vehicles, including engines with high speed direct injection (high speed direct injection, abbreviated as HSDI).

The present invention can also provide improved performance to modern diesel engines having high pressure fuel systems by controlling the amount of external deposits on injectors, for example deposits formed in the injector nozzle and/or at the injector tip. The ability to control the formation of internal nozzle deposits and external nozzle deposits is a major advantage of the present invention.

Preferably, the present invention may reduce or prevent the formation of external deposits on the nozzle. Thus, the present invention can provide a "keep clean" performance with respect to external deposits on the nozzle.

Preferably, the present invention may reduce or remove existing external deposits on the nozzle. Thus, the invention can provide "cleaning" of external deposits on the nozzle.

Preferably, the present invention can reduce or prevent the formation of internal deposits in diesel engine injectors. Thus, the invention can provide a "keep clean" performance with respect to internal deposits on diesel engine injectors.

Preferably, the present invention may reduce or remove existing internal deposits in diesel engine injectors. Thus, the invention can provide "cleaning" of internal deposits on the injector of a diesel engine.

The present invention may also relate to the control of deposits on vehicle fuel filters. This may include reducing or preventing the formation of deposits ("keep clean" characteristic) or reduce or remove existing deposits ("clean" characteristic).

Removal or reduction of the VOPD according to the present invention may result in improved engine performance.

The performance improvement of a diesel engine system can be measured in a number of ways. The choice of suitable methods depends on the type of engine and whether "keep clean" and/or "clean" is being defined.

The improvement in "keep clean" performance can be determined by comparison with the base fuel. The "cleaning" characteristic can be defined as improving the performance of an already contaminated engine.

The performance of fuel additives is often evaluated by testing the engine under controlled conditions.

In Europe, the Co-ordinating European Council for the development of performance tests for transportation fuels, lubricants and other fluids (industrial organization, abbreviated as CEC )) has developed a test to test the properties of additives for modern diesel engines such as HSDI engines. The CEC F-98-08 test is used to assess whether diesel fuel for engine operation complies with the new European Union emission regulations, called "Euro 5" regulations. The test uses a Peugeot DW10 engine incorporating Euro 5 injectors and is commonly referred to as the DW10B test. This test measures the reduction in engine power caused by injector deposits and is further discussed in Example 4 below.

Preferably, the use of the fuel composition of the present invention results in a reduction in deposit formation as measured in the DW10B test. When determining the characteristic "maintaining cleanliness" preferably observed a decrease in the frequency of deposits.

When determining the "cleaning" characteristic, the removal of deposits is preferably observed. The DW10B test is used to determine power loss in modern diesel engines incorporating high pressure fuel systems.

Preferably, the use of a fuel composition according to the present invention can provide a "clean" performance in modern diesel engines, that is, slow down or prevent the formation of deposits on the injectors of these engines. Preferably, this characteristic, determined in the DW10B test, is such that the power loss is less than 5%, preferably less than 2%, after 32 hours of engine operation.

Preferably, the use of a fuel composition according to the present invention can provide a "cleaning" characteristic in modern diesel engines, ie deposits already present on the injectors of a contaminated engine can be removed. Preferably, this characteristic, determined in the DW10B test, is such that the power of a dirty engine can be brought within 16 hours, preferably 12 hours, more preferably 8 hours, to a level within 1% equal to that achieved with clean injectors.

In some preferred embodiments, cleaning can also lead to an increase in power. Thus, a contaminated engine can be treated to remove existing deposits and provide additional power gains.

Clean injectors may include new injectors or injectors that have been removed from the engine and physically cleaned, such as in an ultrasonic bath.

The CEC has also developed a new test, commonly referred to as DW10C, which evaluates the ability of a fuel composition to prevent the formation of HOPF, which leads to injector sticking. This test is discussed in Example 5. A modified version of this test, adapted to determine the degree of purification, is discussed in Example 6.

The DW10C test can be used to determine the "keep clean" or "clean" performance of an engine.

In some exemplary embodiments, the present invention provides a "keep clean" performance with respect to HOP formation. On the DW10C rating scale, this characteristic can be at least 7, preferably at least 8, more preferably at least 9.

In some embodiments, a score of at least 9.3, such as at least 9.4, at least 9.5, at least 9.6, or at least 9.7 can be achieved.

In some exemplary embodiments, the present invention provides a "clean-up" characteristic with respect to the VOFD, which allows the removal of existing VOFDs. This characteristic is discussed in the Examples.

The diesel fuel compositions of the present invention may also provide improved performance in conventional diesel engines. Preferably, improved performance results from the combustion of diesel fuel compositions in modern diesel engines incorporating high pressure fuel systems and from the combustion of the compositions in conventional diesel engines. This is important to note as it allows the same fuel to be used in both new engines and older vehicles.

The performance improvement of older engines can be determined in the XUD9 test. This test is considered in Example 5.

Preferably, the use of a fuel composition according to the present invention can provide "cleanliness" in conventional diesel engines, that is, can slow down or prevent the formation of deposits on the injectors of these engines. Preferably, due to the "keep clean" characteristic, after 10 hours of engine operation in the XUD-9 test, a flow reduction of less than 50%, preferably less than 30% is observed.

Preferably, the use of the fuel composition according to the present invention can provide a "cleaning" characteristic in conventional diesel engines, which allows the removal of deposits on the injectors of an already clogged engine. Preferably, due to this characteristic, flow attenuation in a clogged motor can be reduced by 10% or more during 10 hours of operation in the XUD-9 test.

The benefits provided by the present invention allow for much less frequent maintenance of engines, resulting in increased savings and extended maintenance free times.

Preferably, the method and use of the present invention improves the performance of a diesel engine. The performance improvement is preferably selected from one or more of the following benefits:

- reduction of engine power loss;

- reduction of external deposits on diesel engine injectors;

- reduction of internal deposits on diesel engine injectors;

- improved fuel economy;

- reduction of deposits on the fuel filter;

- reduction of emissions into the atmosphere; and

- increasing the duration of non-repair service.

In addition to the benefits listed above, the additives of the present invention may provide additional benefits. For example, the additive may provide lubricity and/or corrosion inhibition and/or improve cold flow.

The diesel fuel composition of the present invention may include one or more additional additives, such as additives commonly added to diesel fuels. These include, for example, antioxidants, dispersing agents, detergents, metal deactivating compounds, wax anti-settling agents, cold flow improvers, cetane improvers, haze-reducing agents, stabilizers, demulsifiers, defoamers, corrosion inhibitors. , lubricity additives, dyes, markers, flame enhancing additives, metal deactivators, odor masking agents, friction modifiers, and conductive agents. Examples of suitable amounts of each of these types of additives are known to those skilled in the art.

In some embodiments, the combination of an additive according to the invention and an additional additive can lead to a synergistic effect in improving performance.

For example, the use of a quaternary ammonium salt additive according to the invention in combination with a cold flow improver can result in a surprising improvement in detergency and/or cold flow compared to using each of the additives alone.

In some embodiments, the use of the quaternary ammonium salt additive of the present invention allows the cold flow additive to be reduced.

For example, the use of a quaternary ammonium salt additive according to the invention in combination with a corrosion inhibitor can lead to an unexpected improvement in detergency and/or corrosion retardation compared to the use of each of the additives alone.

In some embodiments, the use of a quaternary ammonium salt additive according to the present invention allows the amount of added corrosion inhibitor to be reduced.

For example, the use of a quaternary ammonium salt additive according to the invention in combination with a lubricity additive can result in a surprising improvement in detergency and/or lubricity compared to the use of each of the additives alone.

In some embodiments, the use of a quaternary ammonium salt additive according to the present invention allows the lubricity additive to be reduced.

In some preferred embodiments, the diesel fuel composition according to the present invention includes one or more additional detergent additives. Nitrogen-containing detergent additives are preferred.

One or more additional detergent additives can provide a synergistic effect whereby the performance of the combination of the quaternary ammonium salt additive of the invention and the nitrogen-containing detergent additive is superior to that achieved by adding an equivalent amount of each additive alone.

The use of a combination of a quaternary ammonium salt additive and a nitrogen-containing detergent additive also makes it possible to control deposits and improve the performance of a conventional diesel engine.

One or more additional detergent additives may be selected from:

(i) additives based on a quaternary ammonium salt, which is not a compound having formula (I);

(ii) the product of the Mannich reaction between an aldehyde, an amine and an optionally substituted phenol;

(iii) a reaction product derived from a carboxylic acid acylating agent and an amine;

(iv) a reaction product derived from a carboxylic acid acylating agent and hydrazine;

(v) a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine;

(vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride with an amine-containing compound or salt, wherein the product comprises at least one aminotriazole group; and

(vii) a substituted polyaromatic detergent additive.

Preferably one or more additional detergent additives are selected from one or more of the following:

(i) additives based on a quaternary ammonium salt, which is not a compound having formula (I);

(ii) the product of the Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and

(iii) a reaction product of an acylating agent derived from a carboxylic acid and an amine.

The ratio of quaternary ammonium salt additive to nitrogen detergent additive is preferably 5:1 to 1:5, more preferably 2:1 to 1:2.

In some embodiments, the diesel fuel composition further comprises (i) a quaternary ammonium salt additive that is not a compound having formula (I).

The quaternary ammonium salt additive is preferably the reaction product of a nitrogen-containing compound having at least one tertiary amino group and a quaternizing agent.

The nitrogen containing compound may be selected from:

(x) a reaction product of a hydrocarbyl-substituted acylating agent and a compound containing at least one tertiary amino group and a primary amino group, a secondary amino group, or an alcohol group;

(y) a Mannich reaction product containing a tertiary amino group; and

(z) an amine substituted with polyalkylene containing at least one tertiary amino group.

Examples of quaternary ammonium salts and methods for their preparation are discussed in the following patents, which are incorporated herein by reference: US 2008/0307698, US 2008/0052985, US 2008/0113890 and US 2013/031827.

The preparation of some suitable quaternary ammonium salt additives in which the nitrogen compound includes component (x) is discussed in WO 2006/135881 and WO 2011/095819.

Component (y) is a Mannich reaction product containing a tertiary amino group. The preparation of quaternary ammonium salts formed by a nitrogen-containing compound containing component (y) is discussed in US 2008/0052985.

The preparation of additives based on quaternary ammonium salts, including the use of a nitrogen-containing compound containing component (z), is discussed, for example, in US 2008/0113890.

To obtain a quaternary ammonium salt additive (i), a nitrogen-containing compound having a tertiary amino group is reacted with a quaternizing agent.

The quaternizing agent may preferably be selected from esters and non-esters.

Quaternizing agents preferred for use in the present invention include dimethyl oxalate, methyl 2-nitrobenzoate, methyl salicylate, and styrene oxide or propylene oxide, optionally in combination with an additional acid.

A particularly preferred additional quaternary ammonium salt suitable for use in the present invention is formed by the reaction of methyl salicylate or dimethyl oxalate with the reaction product of polyisobutylene (PIB, abbr. polyisobutylene) substituted succinic anhydride, in which PIB has a number average molecular weight of between 700 up to 1300, and dimethylaminopropylamine.

Other suitable quaternary ammonium salts include quaternized terpolymers, such as those discussed in US 2011/0258917, quaternized copolymers, such as those discussed in US 2011/0315107, and acid-free quaternized nitrogen compounds, as discussed in US 2012/0010112.

Additional quaternary ammonium compounds suitable for carrying out the present invention include the quaternary ammonium compounds discussed in the applications of the authors of the present invention, which are simultaneously under consideration with this work, i.e. in WO 2011095819, WO 2013/017889, WO 2015/011506, WO 2015/011507, WO 2016/016641 and PCT/GB 2016/052312.

In some embodiments, the diesel fuel composition used according to the present invention comprises from 1 to 500 ppm, preferably from 50 to 250 ppm of a quaternary ammonium salt additive according to the present invention and from 1 to 500 ppm, preferably from 50 to 250 ppm additional additive (i) based on a quaternary ammonium compound.

In some embodiments, the diesel fuel composition further comprises (ii) a Mannich reaction product between an aldehyde, an amine, and an optionally substituted phenol. Such a Mannich reaction product is preferably not a quaternary ammonium salt.

Preferably, an aliphatic aldehyde is used as the aldehyde component used to prepare the additive based on the Mannich reaction product. Preferably the aldehyde contains from 1 to 10 carbon atoms. Most preferably, the aldehyde is formaldehyde.

Amines suitable for the preparation of Mannich reaction product additives include monoamines and polyamines. One suitable monoamine is butylamine.

The amine used to prepare the Mannich reaction product additive is preferably a polyamine. It may be selected from any compounds containing two or more amino groups. Preferably the polyamine is a polyalkylene polyamine, preferably a polyethylene polyamine. Most preferably, the polyamine comprises tetraethylenepentamine or ethylenediamine.

Optionally, the substituted phenol component used to make the Mannich reaction product additive may have 0 to 4 substituents on the aromatic ring (other than the phenol OH group). For example, it may be hydrocarbyl-substituted cresol. Most preferably the phenolic component is a mono-substituted phenol. Preferably it is a phenol substituted with hydrocarbyl. Preferred hydrocarbyl substituents are alkyl substituents containing 4 to 28 carbon atoms, in particular 10 to 14 carbon atoms. Other preferred hydrocarbyl substituents are polyalkenyl substituents. The number average molecular weight of the polyisobutenyl substituents is from 400 to 2500, for example from 500 to 1500.

In some embodiments, the diesel fuel composition of the present invention comprises 1 to 500 ppm, preferably 50 to 250 ppm of a quaternary ammonium salt and 1 to 500 ppm, preferably 50 to 250 ppm of additive (ii ) based on the product of the Mannich reaction.

In some embodiments, the diesel fuel composition further comprises (iii) a reaction product of an acylating agent derived from a carboxylic acid and an amine.

In this work, such products can also be generically referred to as acylated nitrogen compounds.

Suitable acylated nitrogen compounds can be prepared by reacting a carboxylic acid acylating agent with an amine and are known to those skilled in the art.

Preferred hydrocarbyl substituted acylating agents are polyisobutenyl succinic anhydrides. These compounds are commonly referred to as "PIBSA" (polyisobutenyl succinic anhydride) and are known to those skilled in the art.

Both traditional polyisobutenes and so-called "highly reactive" polyisobutenes are suitable for practicing the invention.

Particularly preferred PIBSAs are compounds in which the molecular weight (Mn) of the PIB is from 300 to 2800, preferably from 450 to 2300, more preferably from 500 to 1300.

In preferred embodiments, the reaction product of an acylating agent derived from a carboxylic acid and an amine comprises at least one primary or secondary amino group.

Preferred acylated nitrogen compounds useful in the present invention are prepared by reacting an acylating agent derived from polyisobutene-substituted succinic acid (e.g., anhydride, acid, ester, etc.) wherein the number average molecular weight (Mn) of the polyisobutene substituent is between 170 up to 2800, with a mixture of ethylene polyamines containing from 2 to about 9 nitrogen atoms of the amino group, preferably from about 2 to about 8 nitrogen atoms per ethylene polyamine, and from about 1 to about 8 ethylene groups. Such acylated nitrogen compounds are preferably produced in a reaction in which the molar ratio of acylating agent:amino compound is 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 2:1 to 1:2, and most preferably from 2:1 to 1:1. In particularly preferred embodiments, acylated nitrogen compounds are prepared by reacting an acylating agent with an amine compound in a molar ratio of 1.8:1 to 1:1.2, preferably 1.6:1 to 1:1.2, more preferably from 1.4:1 to 1:1.1 and most preferably from 1.2:1 to 1:1. Acylated amino compounds of this type and their preparation are well known to those skilled in the art and are discussed, for example, in EP 0565285 and US 5925151.

In some preferred embodiments, the composition includes a detergent additive that is formed by the reaction of an acylating agent derived from polyisobutene-substituted succinic acid and polyethylenepolyamine. Suitable compounds are discussed, for example, in WO 2009/040583.

In some embodiments, the diesel fuel composition according to the present invention comprises from 1 to 500 ppm, preferably from 50 to 250 ppm of a quaternary ammonium salt according to the first aspect and from 1 to 500 ppm, preferably from 50 to 250 ppm additive, which is the reaction product of acylating agents and amine (iii).

In some embodiments, the diesel fuel composition comprises (iv) the reaction product of an acylating agent derived from a carboxylic acid and hydrazine.

Preferably, the additive comprises the reaction product of a hydrocarbyl-substituted succinic acid or anhydride with hydrazine.

Preferably, the hydrocarbyl group of the hydrocarbyl-substituted succinic acid or anhydride comprises a C ₈ -C ₃₆ group, preferably a C ₈ -C ₁₈ group. Alternatively, the hydrocarbyl group may be a polyisobutylene group having a number average molecular weight of 200 to 2500, preferably 800 to 1200.

Hydrazine has the formula NH ₂ -NH ₂ . The hydrazine may be hydrated or non-hydrated. The use of hydrazine monohydrate is preferred.

The reaction between hydrocarbyl-substituted succinic acid or anhydride and hydrazine results in various products as discussed in US 2008/0060259.

In some embodiments, the diesel fuel composition further comprises (v) a salt derived from the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine. Examples of compounds of this type are discussed in US 2008/0060608.

Such additives may preferably be salts of di-n-butylamine or tri-n-butylamine and a fatty acid having the formula [R'(COOH) _x ] _y' in which each R' is independently a hydrocarbon group containing from 2 up to 45 carbon atoms, and x is an integer from 1 to 4.

In a preferred embodiment, the carboxylic acid comprises tall oil fatty acid (abbreviated as TFA).

Further preferred features of additives of this type are discussed in EP 1900795.

In some embodiments, the diesel fuel composition further comprises (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride with an amine-containing compound or salt, wherein the product comprises at least one aminotriazole group.

Further preferred features of additive compounds of this type are discussed in US 2009/0282731.

In some embodiments, the diesel fuel composition further comprises (vii) a substituted polyaromatic detergent additive.

One preferred compound of this type is the reaction product of ethoxylated naphthol and paraformaldehyde, which is then reacted with a hydrocarbyl substituted acylating agent.

Further preferred features of such detergent additives are discussed in EP 1 884 556.

Any feature of the invention may be combined with any other suitable feature of the invention.

Below the invention is discussed in more detail using the following non-limiting examples. In the examples, the added amounts, expressed in parts per million, mean the amount of active ingredient, and not the amount of added composition containing the active ingredient. All parts per million are parts by weight.

DESCRIPTION OF EXAMPLES OF CARRYING OUT THE INVENTION

Example 1

Additive A1, a quaternary ammonium salt additive according to the invention was prepared as follows:

(a) A mixture of alkenes containing from 20 to 24 carbon atoms was heated with 1.2 molar equivalents of maleic anhydride. After completion of the reaction, excess maleic anhydride was removed by distillation. The anhydride number of the resulting substituted succinic anhydride was determined and was 2.591 mmol.g ^-1 .

The resulting product was then heated with one molar equivalent of polypropylene glycol, the number average molecular weight of which was 425, and the reaction was monitored using Fourier transform infrared spectroscopy (English Fourier transform infrared spectroscopy, abbreviated as FTIR), recording the formation of a product that is a half-ester /semi-acid.

(b) The reaction of 1 molar equivalent of diethylethanolamine with 1.5 molar equivalents of butylene oxide and 6 molar equivalents of water was carried out in toluene at 60° C. for 10 hours in the presence of the half-ester/half-acid obtained in step (a) to give a quaternary ammonium compound . Volatile products were removed in vacuo.

Compounds A2-A21 listed in Table 1 were prepared in a similar manner.

Example 2

Diesel fuel compositions were prepared by dosing additives to aliquots taken from a single batch of RF06 base fuel.

The compositions were tested using a screening test, the results of which correlate with the ability to combat VOFD, determined in the test DW10C.

In this test, the fuel compositions were tested on jet fuel thermal oxidation testing equipment. In this modified test, 800 ml of fuel was passed over a heated tube at a pressure of approximately 540 psi (approximately 3.7×10 ⁶ Pa). The duration of the test was 2.5 hours. At the end of the test, the amount of deposits on the tube was compared with a reference value.

The values shown in Table 2 represent the percentage reduction in deposit thickness compared to deposits obtained by passing the base fuel.

Comparative additive C1 is dodecenyl-substituted succinic acid.

Comparative additive C2 is a polyisobutenyl (PIB) substituted succinic acid in which the number average molecular weight of PIB is 1000.

Table 3 below shows the characteristics of the main RF06 fuel.

Example 3

The performance of the fuel compositions of Example 2 when burned in modern diesel engines having a high pressure fuel system can be determined by the CECF-98-08 DW10 method. In this paper, this method is referred to as the DW10B test.

A PSA DW10BTED4 engine was used to determine nozzle clogging. In general, the engine had the following characteristics:

This engine has been selected as representative of European high speed modern direct injection diesel engine designs that can meet current and future European emission requirements. The common rail injection system uses a highly efficient nozzle design with a rounded inlet edge and tapered spray channels for optimum hydraulic flow. By operating this type of nozzle with high pressure fuel, increased combustion efficiency, reduced noise and reduced fuel consumption can be achieved, but such nozzles are susceptible to influences that can disrupt fuel flow, such as deposits in the spray holes. The presence of such deposits causes a significant reduction in engine power and increased emissions of untreated gases into the atmosphere.

The test was carried out on advanced design injectors, which are an example of a Euro V injector design that may be used in the future.

It is believed that it would be prudent to reliably establish a reference point for the baseline of the injectors before starting fouling testing, and thus a sixteen-hour program to prepare for injector testing using a non-fouling reference fuel has been proposed.

A detailed description of the test method for CEC F-98-08 can be provided by CEC. The coking cycle is briefly described below.

1. Warm-up cycle (12 minutes) in the following mode:

2. 8 hours of engine operation consisted of 8 repetitions of the following cycle:

3. Cool down to idle for 60 seconds and idle for 10 seconds

4. 4 hour soak period

The standard CEC F-98-08 test method consists of a 32-hour engine run consisting of 4 repetitions of steps 1-3 above and 3 repetitions of step 4, i.e. the total duration of the test is 56 hours, excluding warm-up and cool-down periods.

Example 4

The ability of additives according to the invention to remove "internal diesel injector deposits" (FIFO) can be determined by the test method CEC F-110-16 developed by the European Council for Coordination. The PSA DW10C engine is used in this test.

The engine has the following characteristics:

The test fuel (RF06) was supplemented with 0.5 mg/kg Na as sodium naphthenate + 10 mg/kg dodecyl succinic acid (denoted DDSA).

The test procedure consists of main stroke cycles followed by soak periods followed by a cold start (cold start).

The main stroke cycle consists of two stages of work at a certain speed and load, which are repeated for 6 hours, as indicated below.

Acceleration periods of 30 seconds were included in the duration of each stage.

Each cycle was repeated 6 times, i.e. the full phase of the main course was 6 hours

During the main stroke, parameters were observed and recorded, including gas pedal position, ECU (short for engine control unit) error codes, injector balance ratio, and spontaneous engine shutdowns.

The engine is then kept at normal temperature for 8 hours.

After the soak period, the engine is restarted. The starting device (starter) operates for 5 seconds; if the engine does not start, then the engine is left for another 60 seconds and then another attempt is made. No more than 5 attempts are allowed.

If the engine starts, leave the engine idling for 5 minutes. Determine the individual exhaust gas temperatures and record the maximum temperature difference. An increased fluctuation in exhaust gas temperatures in different cylinders clearly indicates that HFFDs are deposited on the injectors, which cause either a slowdown in the opening of the injector orifice, or an unnecessary increase in the duration of stay in the open state.

Below is an example showing all exhaust gas temperatures with a deviation of <30°C, indicating no sticking caused by HFPD.

Maximum temperature deviation (deg. С)

The full test includes 6 cold starts, but does not include zero hour cold starts, and five 6-hour main stroke cycles, for a total engine run time of 30 hours.

The obtained data were entered into the Evaluation table. This allows you to get an estimate from the results of the test. A maximum score of 10 indicates no running or serviceability problems with the engine during the entire test.

One example is shown below:

Example 5

The effectiveness of the additives according to the invention on older conventional diesel engines was evaluated using a standard industry test, CEC test method No. CEC F-23-A-01.

This test measures injector nozzle coking in a Peugeot XUD9 A/L engine, and this test distinguishes between fuels by their tendency to form coco-like deposits on the injector nozzle. The formation of coke on the nozzle is the result of carbon deposition between the nozzle needle and the needle seat. Carbon deposits result from exposure of the nozzle needle and seat to combustion gases and can cause unwanted fluctuations in engine performance.

The Peugeot XUD9 A/L engine is a 1.9 liter displacement 4-cylinder indirect injection diesel engine provided by Peugeot Citroen Motors specifically for CEC PF023 testing.

Clean injectors with unblunted injector needles were installed in the tested engine. Prior to the test, the airflow was determined using a flow meter at various positions of the raised needle. The engine worked for 10 hours in a cyclic mode.

The ability of the fuel to enhance the formation of deposits on the fuel injectors was determined by re-measuring the air flow through the injector nozzle at the end of the test and comparing the results with the values obtained before the test. The results are expressed as a percentage reduction in air flow at various needle-raised positions in all nozzles. The level of coking of the nozzle during the combustion of a certain fuel was taken as the average value of the decrease in the amount of air flow when the needle was raised by 0.1 mm in all four nozzles.

The results of the presented test using certain combinations of additives according to the invention are presented in Table 3. In each case, a certain amount of active additive was added to the base fuel RF06, corresponding to the specification presented in Table 3 above (Example 2).

Claims (56)

1. A method for producing a fuel composition, where the method includes obtaining a Quaternary ammonium salt by reaction of (a) a tertiary amine having the formula R ¹ R ² R ³ N, where R ¹ , R ² and R ³ each independently represents an optionally substituted hydrocarbyl group, with (b) an acid-activated alkylating agent in the presence of (c) a compound having the formula HOOCXCOO-(R ⁴ O) _n -R ⁵ , where R ⁴ is an optionally substituted alkylene group, R ⁵ is hydrogen or an optionally substituted alkyl, alkenyl or an aryl group, X is an alkylene group substituted with alkyl or alkenyl, and n is 0 or a positive integer, provided that n is not 0 if R ⁵ is hydrogen; and mixing the quaternary ammonium salt with the fuel; where n is a positive integer and/or X is CH ₂ CHR or CHRCH ₂ where R is an alkyl or alkenyl group having 20 to 24 carbon atoms. 2. The method of claim 1 wherein component (b) is an epoxide. 3. The method according to p. 1 or 2, where R ¹ and R ² are optionally substituted with one or more groups selected from halogen, hydroxy-, alkoxy-, keto-, acyl, cyano-, mercapto-, alkylmercapto-, dialkylamino- , nitro-, nitroso- and sulfoxy groups; R ³ is optionally substituted with one or more groups selected from halo, hydroxy, alkoxy, keto, acyl, cyano, mercapto, alkylmercapto, amino, alkylamino, nitro, nitroso, sulfoxy, amido , alkylamido, imido and alkylimido groups, or R ³ is a hydroxyethyloxyethyl group or benzyl; R ⁴ is an unsubstituted alkylene group; a R ⁵ is an alkyl or alkenyl group optionally substituted with a hydroxy or ester group. 4. Fuel composition obtained by the method according to any one of paragraphs. 1-3. 5. The use of Quaternary ammonium compounds obtained by the method according to any one of paragraphs. 1-3 as an additive for a fuel composition. 6. The method of improving the performance of the engine, characterized in that the method includes combustion in the engine of the fuel composition obtained by the method according to any one of paragraphs. 1-3. 7. Composition, method or use according to any one of the preceding claims, characterized in that HOOCXCOO-(R ⁴ O) _n -R ⁵ is derived from hydrocarbyl-substituted succinic acid or hydrocarbyl-substituted succinic anhydride. 8. Composition, method or use according to any one of the preceding claims, characterized in that each R ⁴ is ethylene or propylene, preferably -CH ₂ CH ₂ - or -CH(CH ₃ )CH ₂ -, more preferably -CH(CH ₃ ) CH ₂ -. 9. Composition, method or use according to any one of the preceding claims, characterized in that R ⁵ is hydrogen and n is at least 1. 10. Composition, method or application according to any one of paragraphs. 1-8, characterized in that R ⁵ is an optionally substituted alkyl group containing from 4 to 40 carbon atoms, and n is from 0 to 40. 11. The composition, method or use according to any one of the preceding claims, characterized in that each of R ¹ and R ² independently represents an optionally substituted alkyl group containing from 1 to 12 carbon atoms. 12. Composition, method or use according to any one of the preceding claims, characterized in that R ³ represents an alkyl or hydroxyalkyl group containing from 1 to 10 carbon atoms. 13. Composition, method or application according to any one of paragraphs. 1-11, characterized in that R ³ is selected from: (1) a polyisobutenyl group whose molecular weight is 100 to 5000, preferably 450 to 2500; (2) an optionally substituted alkylenephenol moiety having formula (A) or formula (B):

in which n is from 0 to 4, preferably 1, R ^x is an optionally substituted hydrocarbyl group, R ^y is an optionally substituted alkyl, alkenyl or aryl group; and L is a connecting group; and (3) a succinimide moiety having the formula:

in which R ^z is an optionally substituted hydrocarbyl group, and L is a connecting group. 14. Composition, method or application according to any one of paragraphs. 1-12, characterized in that the quaternary ammonium compound is a reaction product: (a) a tertiary amine having the formula R ¹ R ² R ³ N, where each of R ¹ , R ² and R ³ independently represents an optionally substituted alkyl group containing 1 to 12 carbon atoms; (b) an epoxide selected from styrene oxide, ethylene oxide, propylene oxide, butylene oxide, epoxyhexane, octenoxide, stilbene oxide, 2-ethylhexylglycidyl ether, 1,2-epoxydecane, and other alkyl and alkenyl epoxides containing from 2 to 50 carbon atoms; and (c) a compound having the formula HOOCXCOO-(R ⁴ O) _n -R ⁵ , wherein X is CH ₂ CHR or CHRCH ₂ , in which R is an optionally substituted hydrocarbyl group; and n is greater than 1, R ⁴ is an ethylene or propylene group, and R ⁵ is hydrogen; or n is 0 or and R ⁵ is a C ₁ -C ₂₀ alkyl group. 15. Composition, method or application according to any one of paragraphs. 1-12 or 14, characterized in that the quaternary ammonium compound is a reaction product: (a) a tertiary amine having the formula R ¹ R ² R ³ N, where each of R ¹ , R ² and R ³ independently represents an alkyl or hydroxyalkyl group containing from 1 to 6 carbon atoms; (b) an epoxide selected from propylene oxide, butylene oxide and 2-ethylhexylglycidyl ether; and (c) a compound having the formula HOOCXCOO-(R ⁴ O) _n -R ⁵ which is the reaction product of succinic acid or succinic anhydride containing a C ₂₀ -C ₂₄ -alkyl or -alkenyl substituent and an alcohol selected from polypropylene glycol, the number average molecular weight of which is from 300 to 800, 2-ethylhexanol and butanol. 16. A composition, method or use according to any one of the preceding claims, characterized in that the composition is a diesel fuel composition. 17. Composition, method or application according to claim 16, characterized in that the diesel fuel composition includes one or more additional detergent additives selected from: (i) quaternary ammonium salt additives; (ii) the product of the Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; (iii) a reaction product of an acylating agent derived from a carboxylic acid and an amine; (iv) a reaction product of an acylating agent derived from a carboxylic acid and hydrazine; (v) a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine; (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride with an amine-containing compound or salt, wherein the product comprises at least one aminotriazole group; and (vii) a substituted polyaromatic detergent additive. 18. A composition, method or use according to any one of the preceding claims, characterized in that the composition is a diesel fuel composition comprising a mixture of two or more quaternary ammonium salt additives. 19. The method or application according to any one of paragraphs. 5-18, characterized in that the additive is used as a detergent additive for a diesel fuel composition designed to control deposits in a diesel engine. 20. The method or application according to any one of paragraphs. 5-19 carried out in a modern diesel engine having a high pressure fuel system. 21. The method or application according to any one of paragraphs. 5-20 providing a "keep clean" characteristic. 22. The method or application according to any one of paragraphs. 19-21, characterized in that the deposits are deposits on the nozzles. 23. Method or use according to claim 22, characterized in that the deposits are internal deposits on the injectors of a diesel engine. 24. The method or application according to any one of paragraphs. 5-23 that provide improvements to a feature selected from one or more of the following features: - reduction of engine power loss; - reduction of external deposits on diesel engine injectors; - reduction of internal deposits on diesel engine injectors; - improved fuel economy; - reduction of deposits on the fuel filter; - reduction of emissions; and - increase in the duration of non-repair service. 25. The method or use of claim 24 that improves the performance of modern diesel engines having a high pressure fuel system and also improves the performance of traditional diesel engines. 26. Application according to any one of paragraphs. 5-25 providing one or more additional beneficial effects selected from improving lubricity, inhibiting corrosion, and improving cold flow. 27. The composition according to any one of paragraphs. 4 or 7-18, which further comprises one or more additional additives selected from lubricity improvers, corrosion inhibitors, and cold flow improvers.