Uses and methods

Abstract

The use of a nitrogen-containing compound as an additive in a diesel fuel composition reduces the effects of deposits in the exhaust gas recirculation system of a diesel engine when the diesel fuel composition is combusted. The nitrogen-containing compound comprises at least 4 mass% nitrogen atoms and, in some embodiments, less than 5 N-H bonds.

Description

[0001] The present invention relates to methods and uses for improving the performance of a diesel engine. In particular, the present invention relates to reducing a specific type of deposits occurring in the exhaust gas recirculation system of a diesel engine.

[0002] Installing Exhaust Gas Recirculation (EGR) systems on diesel vehicles to reduce NO x Emissions. This is achieved by recirculating the exhaust gas to the combustion chamber in a controlled manner and thereby increasing the heat capacity of the gas in the combustion chamber and reducing the oxygen concentration in the gas in the combustion chamber. Several types of EGR systems have been developed. The high-pressure EGR system is arranged to divert the exhaust gas from the combustion chamber before the exhaust gas reaches any turbocharger and / or diesel particulate filter present in the engine, and supply the exhaust gas to the intake manifold downstream of the compressor. The high-pressure EGR system thus operates on the high-pressure side of the intake and exhaust manifolds and supplies unfiltered recirculated exhaust gas to the combustion chamber. The low-pressure EGR system is arranged to divert the exhaust gas from the combustion chamber downstream of any turbocharger and / or diesel particulate filter present in the engine, and supply the exhaust gas to the intake duct upstream of the compressor. The low-pressure EGR system thus operates on the low-pressure side of the intake and exhaust manifolds and supplies filtered recirculated exhaust gas to the combustion chamber. Hybrid (or combined) EGR systems integrate high-pressure EGR and low-pressure EGR on the same engine to combine the benefits of each system. A dedicated EGR (D-EGR) system is arranged to direct the entire exhaust gas of a subgroup of power cylinders (dedicated cylinders) directly into the intake manifold.

[0003] Over time, deposits may form within the EGR system. This is a particular problem in diesel engines with high pressure EGR systems, as the recirculated exhaust stream is taken upstream of any turbocharger and diesel particulate filter, which means that problematic particulate combustion products are reintroduced into the intake manifold and combustion chamber. One area where such deposits cause particular problems is within the cooler assembly of the EGR system. If the level of deposits becomes significant, the engine management system in a sophisticated diesel engine may cause the engine to run at reduced performance and / or enter a safe operating mode. This condition will have a significant impact on the operability of the vehicle and will need to be checked by a suitably qualified workshop.

[0004] A typical EGR system comprises an intake pipe, a valve, a housing, a cooler and an outlet pipe. Deposits accumulate on the inner surfaces of all parts of the EGR system, but particularly in the cooler.

[0005] It would be beneficial to combat such deposits, particularly in coolers of EGR systems, and particularly in coolers of high pressure EGR systems.

[0006] The present inventors have surprisingly found that the inclusion of certain compounds as fuel additives can reduce deposit formation in EGR systems.

[0007] According to a first aspect of the present invention, there is provided the use of one or more nitrogen-containing compounds as an additive in a diesel fuel composition to reduce the effect of deposits in the exhaust gas recirculation system of a diesel engine when the diesel fuel composition is combusted, wherein the one or more nitrogen-containing compounds comprises at least 4 mass % nitrogen atoms.

[0008] According to a second aspect of the invention, there is provided a method for reducing the effects of deposits in an exhaust gas recirculation system of a diesel engine, the method comprising combusting in the engine a diesel fuel composition comprising as an additive one or more nitrogen-containing compounds, wherein the nitrogen-containing compounds comprise at least 4 mass % nitrogen atoms.

[0009] The present invention relates to a method and use of reducing the effects of deposits in the EGR system of a diesel engine.The presence of such deposits generally has a negative impact on the performance of the engine.

[0010] Reducing the impact of sediment may involve reducing or preventing the formation of sediment and / or removing existing sediment and / or changing the properties of sediment.

[0011] In some embodiments, reducing the effects of deposits may involve changing the properties of the deposits. This means that the structure or composition of the deposits formed is different in a way that is less detrimental to engine performance, such as by increasing the ignitability and / or thermal conductivity of the deposits.

[0012] In some preferred embodiments, reducing the effects of deposits involves reducing and / or preventing the formation of deposits and / or removing existing deposits.

[0013] Preferably, the use of the first aspect reduces deposit formation in the EGR system.

[0014] Preferably, the method of the second aspect reduces deposit formation in the EGR system.

[0015] Preferred features of the first and second aspects of the invention will now be described.

[0016] The present invention relates to the use of an additive in a diesel fuel composition for reducing deposit formation in an exhaust gas recirculation (or EGR) system. The additive is a nitrogen-containing compound containing at least 4% by mass of nitrogen atoms, and mixtures thereof. Such an additive may be referred to herein as an EGR deposit control additive.

[0017] For the avoidance of doubt, unless otherwise indicated, the nitrogen-containing compounds used in the present invention may comprise mixtures of compounds, and references to additives include mixtures. In particular, mixtures of isomers and mixtures of homologues are within the scope of the present invention. Those skilled in the art will appreciate that commercial sources of some of the additive compounds described herein may contain mixtures of isomers and / or mixtures of homologues.

[0018] The nitrogen-containing compound used in the present invention contains at least 4% by mass of nitrogen atoms. This means that at least 4% of the molecular weight of the nitrogen-containing compound is provided by nitrogen atoms, preferably by number average molecular weight. The amount of nitrogen by mass in such a compound can be calculated using standard methods or determined by elemental analysis. Since the nitrogen-containing compound can be a mixture of compounds, such as isomers, homologues and / or structurally similar compounds produced by the reaction for forming the nitrogen-containing compound, the mass percentage of nitrogen mentioned above is suitably an average value of such a mixture of nitrogen-containing compounds.

[0019] Preferably, the nitrogen-containing compound comprises at least 5 mass % nitrogen atoms, preferably at least 7 % or at least 10 %.

[0020] Suitably, the nitrogen containing compound comprises at most 50 mass % nitrogen atoms or at most 40%. Suitably, the nitrogen containing compound comprises at most 35 mass % nitrogen atoms, suitably at most 30%.

[0021] Suitably, the nitrogen-containing compound comprises 4 to 50 mass % nitrogen atoms, suitably 4 to 40%.In a preferred embodiment, the nitrogen-containing compound comprises 4 to 35 mass % nitrogen atoms, suitably 5 to 30% or 10 to 30%.

[0022] The present inventors have discovered that this relatively high proportion of nitrogen atoms present in the additive is required to provide a beneficial effect in an EGR system of a diesel engine as described herein.

[0023] The nitrogen-containing compound used in the present invention preferably contains no more than 12 NH bonds. NH bonds can be referred to as "free" NH bonds. Preferably, the nitrogen-containing compound contains less than 5 NH bonds, less than 4 NH bonds or less than 3 NH bonds. Preferably, the above-mentioned limit on the number of NH bonds only applies to the NH bonds on the amino group in the nitrogen-containing molecule. For example, the NH bonds of the amide group and / or the NH bonds of the nitrogen atom in the aromatic heterocycle are not included in the NH bond limits described herein.

[0024] The present inventors have discovered that such relatively low numbers of such free NH bonds in the additive containing a relatively high proportion of nitrogen may be required for the nitrogen-containing compound to provide a beneficial effect in the EGR system of a diesel engine as described herein.

[0025] Suitable nitrogen-containing compounds are the reaction products of a) a hydrocarbyl-substituted reagent and b) a nitrogen-containing reagent.

[0026] In some embodiments, the nitrogen-containing compound is the reaction product of:

[0027] As further described below

[0028] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0029] b) Nitrogen-containing reagents.

[0030] In some embodiments, the nitrogen-containing compound is the reaction product of:

[0031] As further described below

[0032] a) amines or polyamines containing hydrocarbon groups;

[0033] b) nitrogen-containing reagents; and

[0034] c) Aldehydes.

[0035] The nitrogen-containing compound can be a mixture of the reaction product of a) a hydrocarbyl-substituted reagent and b) a nitrogen-containing reagent. For example, as further described below, the nitrogen-containing compound can comprise the reaction product of:

[0036] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0037] b) nitrogen-containing reagents;

[0038] The reaction products of:

[0039] a) amines or polyamines containing hydrocarbon groups;

[0040] b) nitrogen-containing reagents; and

[0041] c) Aldehydes.

[0042] When the nitrogen-containing compound is the reaction product of a) a hydrocarbyl-substituted reagent and b) a nitrogen-containing reagent, the nitrogen-containing reagent b) suitably comprises a nitrogen-containing group A. The hydrocarbyl-substituted reagent a) suitably comprises a hydrocarbyl group R 1 .

[0043] The A group suitably provides a significant amount of the required nitrogen content of the additive, and R 1 The group may be a solubilizing group which provides the additive with sufficient solubility in diesel fuel to render the additive effective in use. A and R are suitably selected 1 The group is to provide the desired nitrogen content of at least 4 mass % in the nitrogen-containing compound.

[0044] In some embodiments, the nitrogen-containing reagent b) suitably comprises a nitrogen-containing heterocyclic group. The heterocyclic group suitably provides a significant amount of the required nitrogen content of the additive. In such embodiments, the A group of the nitrogen-containing reagent b) is a nitrogen-containing heterocyclic group.

[0045] The nitrogen-containing heterocyclic group can be any heterocyclic group, aromatic or aliphatic, containing at least one nitrogen atom. The nitrogen-containing heterocyclic group can contain other heteroatoms, such as at least one oxygen atom or at least one sulfur atom, preferably at least one oxygen atom. In some embodiments, the nitrogen-containing heterocyclic group does not contain other heteroatoms except nitrogen. The nitrogen-containing heterocyclic group of the A group can be selected from optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, five-membered heterocyclic ring such as pyrazole or imidazole or benzo-fused five-membered heterocyclic ring such as benzimidazole and its derivatives. The nitrogen-containing heterocyclic group is suitably selected to be compatible with R 1 Any further nitrogen atoms present in the group together provide the required nitrogen content of at least 4 mass %.

[0046] Preferably, the A group is selected from an optionally substituted five-membered nitrogen-containing heterocyclic ring or a benzo-fused five-membered nitrogen-containing heterocyclic ring and derivatives thereof. Preferably, the A group is an optionally substituted benzotriazole, indazole, triazole, tetrazole, imidazole, benzimidazole or imidazoline, or a derivative thereof. Suitably, the A group is an optionally substituted benzotriazole, benzimidazole, indazole, triazole or tetrazole.

[0047] In some embodiments, the A group is an acyclic nitrogen-containing group. In such embodiments, the A group can be an amine or a polyamine. Suitable polyamines can have formula (II):

[0048]

[0049] wherein n is 1 to 10. The nitrogen-containing compound may be a mixture of compounds having different values ​​of n in the "A" group. Thus n is suitably the average of the different values ​​of n present in the mixture. Thus n may be 1 to 10, i.e. a non-integer value of 1.0 to 10.0. Preferably, n is 1 to 6, 1 to 4 or 1 to 3.

[0050] Thus the A group may be provided by ethylenediamine, diethylenetriamine (DETA) or triethylenetetramine (TETA) or tetraethylenepentamine (TEPA). Preferably, the A group is provided by TETA or TEPA.

[0051] The R of the hydrocarbon-substituted reagent a) 1 The group preferably has a molecular weight (Mn) of at most 1,000, at most 600 or at most 400. 1 The group preferably has a molecular weight (Mn) of at least 50, at least 100 or at least 150. 1The groups have a molecular weight (Mn) in the range of 50-500, preferably 100-400 or 150-350.

[0052] In some embodiments, R 1 The group is a hydrocarbyl group. The term "hydrocarbyl" as used herein refers to a group having a carbon atom directly attached to the remainder of the molecule and having a predominantly aliphatic hydrocarbon character. Suitable hydrocarbyl-based groups may contain non-hydrocarbon moieties. For example, they may contain up to 1 non-hydrocarbyl group for every 10 carbon atoms, as long as such non-hydrocarbyl groups do not significantly alter the predominantly hydrocarbon character of the group. Such groups are known to those skilled in the art and include, for example, hydroxyl, oxygen, halogen (especially chlorine and fluorine), alkoxy, alkyl mercapto, sulfonic acid (sulphoxy) and the like. Preferred hydrocarbyl-based substituents are pure aliphatic hydrocarbons in nature and do not contain such groups.

[0053] The hydrocarbyl-based substituents are preferably predominantly saturated, ie they contain no more than 1 carbon-carbon unsaturated bond for every 10 carbon-carbon single bonds present.

[0054] The hydrocarbyl group preferably comprises at least 10 carbon atoms, more preferably at least 14 carbon atoms or at least 18 carbon atoms. The hydrocarbyl group preferably comprises up to 30 carbon atoms, preferably up to 28 carbon atoms or up to 26 carbon atoms. The hydrocarbyl group may comprise 10 to 30 carbon atoms, 14 to 26 carbon atoms, 18 to 26 carbon atoms or more preferably 20 to 24 carbon atoms.

[0055] The hydrocarbyl substituent may be a mixture of hydrocarbyl groups having the above-mentioned carbon atom ranges on average. The molecular weight of the hydrocarbyl group is therefore suitably defined as the number average molecular weight (Mn). The hydrocarbyl group preferably has an Mn of 50 to 500, preferably 100 to 400 or 150 to 350.

[0056] The skilled artisan is familiar with standard techniques for measuring number average molecular weight, such as by vapor pressure osmometry, end group titration, proton NMR, boiling point elevation, freezing point depression (cryometry), and GPC (gel permeation chromatography).

[0057] The hydrocarbyl substituent may be an olefin having the carbon number and / or Mn as described above.

[0058] Hydrocarbyl-based substituents can be prepared from homopolymers or interpolymers (e.g., copolymers, terpolymers) of monoolefins and diolefins having 2 to 10 carbon atoms, such as ethylene, propylene, butane-1, isobutylene, butadiene, isoprene, 1-hexene, 1-octene, etc. These olefins are preferably 1-monoolefins. The hydrocarbyl substituents can also be derived from halogenated (e.g., chlorinated or brominated) analogs of these homopolymers or interpolymers. Alternatively, the substituents can be prepared from other sources, such as monomeric high molecular weight olefins (e.g., 1-tetra-contene) and their chlorinated and hydrochlorinated analogs, aliphatic petroleum fractions, such as paraffins and their cracked and chlorinated and hydrochlorinated analogs, white oils, such as synthetic olefins prepared by the Ziegler-Natta process (e.g., poly(ethylene) esters), and other sources known to those skilled in the art. If desired, any unsaturation in the substituent can be reduced or eliminated by hydrogenation according to procedures known in the art.

[0059] The hydrocarbyl substituent may be a polyisobutylene, preferably having the carbon number and / or Mn specified above. Conventional polyisobutylenes and so-called "highly reactive" polyisobutylenes are suitable for use in the present invention. Highly reactive polyisobutylenes are defined herein as polyisobutylenes in which at least 50%, preferably 70% or more, of the terminal olefinic double bonds are of the vinylidene type as described in EP0565285. Particularly preferred polyisobutylenes are those having greater than 80 mol % and up to 100% terminal vinylidene groups, such as those described in EP1344785.

[0060] Other preferred hydrocarbyl groups include those having internal olefins, for example as described in applicant's published application WO2007 / 015080.

[0061] Internal olefins as used herein refer to any olefins containing mainly non-alpha double bonds, i.e., beta or higher olefins. Such materials are preferably substantially completely beta or higher olefins, e.g., containing less than 10 wt% alpha olefins, more preferably less than 5 wt% or less than 2 wt%. Typical internal olefins include Neodene 1518IO available from Shell.

[0062] Internal olefins are sometimes referred to as isomerized olefins and may be prepared from alpha olefins by isomerization processes 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 do not necessarily have to be prepared by isomerization.

[0063] The reaction of the hydrocarbyl-substituted reagent a) and the nitrogen-containing reagent b) preferably forms a nitrogen-containing group A and a hydrocarbyl group R 1 The linker L between them. The L group can be a bond, an amine, an amide, succinimide, succinic acid or an amide of succinic acid.

[0064] The nitrogen-containing compound which is the reaction product of a) a hydrocarbyl-substituted reagent and b) a nitrogen-containing reagent is suitably of formula (I):

[0065] ALR 1

[0066] (I)

[0067] in:

[0068] A is a nitrogen-containing group;

[0069] L is a bond or a linker; and

[0070] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000. Groups A, L and R 1 Preferably as defined above.

[0071] Therefore, the nitrogen-containing compound used in the first and second aspects of the present invention is preferably of formula (I).

[0072] In some embodiments, the nitrogen-containing compound is the reaction product of a) a hydrocarbyl-substituted reagent and b) a nitrogen-containing reagent, wherein a) is a hydrocarbyl-substituted carboxylic acylating agent.

[0073] Thus in such an embodiment, the nitrogen-containing compound is preferably the reaction product of:

[0074] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0075] b) Nitrogen-containing reagents.

[0076] In such an embodiment, the hydrocarbon group R 1 The linker L between the nitrogen-containing group A is provided by an amide of succinic acid or a succinic acid derivative as further described below.

[0077] Suitably, component a) comprises a group R as defined above 1 Suitably, component a) comprises a hydrocarbyl group as defined above, preferably a polyisobutylene or olefin group as defined above.

[0078] Component a) suitably has the formula (aI):

[0079]

[0080] Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000.

[0081] R 1Preferred are hydrocarbyl groups as discussed above, preferably having from 18 to 26 carbon atoms and / or an Mn of from 100 to 400.

[0082] R 1 It may be a polyisobutylene group or an internal olefin group having 18 to 26 carbon atoms and / or an Mn of 100 to 400.

[0083] In some embodiments, component a) is polyisobutenyl succinic anhydride. These compounds are often referred to as "PIBSA" and are known to those skilled in the art. Suitably, the polyisobutylene group of the PIBSA is as defined above.

[0084] PIBSA can be prepared by reacting polyisobutylene with maleic anhydride.

[0085] The preparation of polyisobutenyl substituted succinic anhydrides (PIBSA) is well documented in the art. Suitable methods include thermally reacting polyisobutene with maleic anhydride (see, for example, US-A-3,361,673 and US-A-3,018,250), or reacting halogenated, particularly chlorinated polyisobutene (PIB) with maleic anhydride (see, for example, US-A-3,172,892). Alternatively, polyisobutenyl succinic anhydrides may be prepared by mixing a polyolefin with maleic anhydride and passing chlorine through the mixture (see, for example, GB-A-949,981).

[0086] In some embodiments, component a) is PIB having an Mn of 250-270.

[0087] In some embodiments, component a) is alkenyl succinic anhydride. These compounds are commonly referred to as "ASA" and are known to those skilled in the art. Suitably, the alkenyl group of ASA is as defined above. Preferably, ASA is C16 to C18 alkenyl succinic anhydride (ASA), such as Pentasize 68.

[0088] The reaction of component a) with component b) suitably forms an amide bond, an imide bond or a mixture thereof.

[0089] Component b) preferably contains reactive amino groups or reactive nitrogen as part of a nitrogen-containing heterocyclic compound.

[0090] In some embodiments, component b) comprises a nitrogen-containing heterocycle, preferably selected from optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, 2-aminoimidazoline, 5-phenyl-2-aminoimidazoline, 5-methyl-2-aminoimidazole, 5-amino-indazole, 6-aminoindazole, 2-aminobenzimidazole, a five-membered heterocyclic ring or a benzo-fused five-membered heterocyclic ring. Preferably, component b) comprises a five-membered heterocyclic ring, such as pyrazole or imidazole, a benzo-fused five-membered heterocyclic ring, such as benzimidazole, an amino-substituted five-membered heterocyclic ring or an amino-substituted benzo-fused five-membered heterocyclic ring. Preferably, component b) comprises benzotriazole, indazole, triazole or tetrazole. Component b) can be selected from optionally substituted benzotriazole, amino-benzotriazole, indazole, amino-indazole, triazole, amino-triazole, tetrazole or amino-tetrazole.

[0091] In some embodiments, component b) comprises an amine or polyamine compound. Suitably, component b) is a polyamine. Suitably, component b) has formula (bI):

[0092]

[0093] wherein n is 1 to 10. The nitrogen-containing compound may be a mixture of compounds having different values ​​of n in the "A" group. Thus n is suitably the average of the different values ​​of n present in the mixture. Thus n may be 1 to 10, i.e. a non-integer value of 1.0 to 10.0. Preferably, n is 1 to 6, 1 to 4 or 1 to 3.

[0094] Component b) may be selected from ethylenediamine, diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA). Component b) may be selected from ethylenediamine, diethylenetriamine (DETA) and triethylenetetramine (TETA).

[0095] Preferably, the nitrogen-containing compound is the reaction product of:

[0096] a) polyisobutenyl succinic anhydride or alkenyl succinic anhydride; and

[0097] b) a polyamine selected from ethylenediamine, diethylenetriamine (DETA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA); or a nitrogen-containing heterocycle selected from optionally substituted benzotriazole, amino-benzotriazole, indazole, amino-indazole, triazole, amino-triazole, tetrazole or amino-tetrazole.

[0098] In such embodiments, the nitrogen-containing compound formed by the reaction of a) and b) may have the structure described below, for example, as the major component in the mixture of compounds produced by the reaction.

[0099] The L group of the nitrogen-containing compound of formula (I) can be provided by an amide of succinic acid or a succinic acid derivative. In such an embodiment, the nitrogen-containing compound formed by the reaction of a) and b) can have formula (III):

[0100]

[0101] in:

[0102] A is a nitrogen-containing group;

[0103] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0104] R 2 OH, NH 2 , OR 4 ,OM,NHR 4 or NR 4 R 5 , or a bond to A, wherein M is a cation, preferably an alkali metal cation or an ammonium cation, and wherein R 4 and R 5 R is independently selected from optionally substituted C1-6 alkyl or alkenyl. 4 and R 5 Quaternary ammonium groups may be included independently.

[0105] Therefore, in some embodiments, the nitrogen-containing compound used in the first and second aspects of the present invention is preferably of formula (III).

[0106] In some preferred embodiments, R 2 is OH, so the L group is the amide of succinic acid.

[0107] R 1 The solubilizing group may be bonded to any of the carbon atoms between the acid and amide groups. 1 A mixture of isomers which differ in the position of the radicals.

[0108] In such an embodiment, R 1 Preferred are hydrocarbyl groups as discussed above, preferably having from 18 to 26 carbon atoms and / or an Mn of from 100 to 400.

[0109] In such an embodiment, R 1 It may be a polyisobutylene group or an internal olefin group having 18 to 26 carbon atoms and / or an Mn of 100 to 400.

[0110] In some embodiments of the nitrogen-containing compound of formula (III), the nitrogen-containing group A can be selected from optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, five-membered heterocyclic ring such as pyrazole or imidazole or benzo-fused five-membered heterocyclic ring such as benzimidazole, and derivatives thereof. Preferably, the A group is selected from optionally substituted five-membered heterocyclic ring or benzo-fused five-membered heterocyclic ring, or derivatives thereof. Preferably, the A group is optionally substituted benzotriazole, indazole, triazole or tetrazole.

[0111] In such an embodiment, the A group is suitably tetrazole. Thus, the nitrogen-containing compound may preferably have the formula (IV):

[0112]

[0113] Where R 1 and R 2 As defined above.

[0114] In such embodiments, the compound of formula (IV) may also exist in the form of an imide having formula (IVb):

[0115]

[0116] In such an embodiment, the nitrogen-containing compound may have formula (IVc), which is an isomer of formula (IV):

[0117]

[0118] Where R 1 and R 2 As defined above.

[0119] In such embodiments, the nitrogen-containing compound may be a mixture of compounds of formula (IV), (IVb) and (IVc).

[0120] In such an embodiment, R 2 Preferably OH or O - X + , wherein X is a cation, such as a metal cation or an ammonium ion.

[0121] In such an embodiment, R 1 Preferred are hydrocarbyl groups having an Mn of 100 to 500, preferably 150 to 350 or 200 to 300.

[0122] For example, R 1 It may be a polyisobutylene or olefin having an Mn of 100 to 500, preferably 150 to 350 or 200 to 300.

[0123] In some embodiments, R 1is a polyisobutylene group, so the nitrogen-containing compound has the formula (IV-A), (IVb-A) or (IVc-A), or a mixture thereof:

[0124]

[0125] wherein n is 1 to 3. The nitrogen-containing compound may be a mixture of compounds having different n values ​​in the polyisobutylene group. Thus n is suitably the average of the different n values ​​present in the mixture. Thus n may be 1 to 3, i.e. a non-integer value of 1.0 to 3.0.

[0126] In some embodiments, R 1 is a C10-24 olefin group, preferably a C12-22 olefin group or a C16-18 olefin group. In such an embodiment, the nitrogen-containing compound may have formula (IV-B), (IVb-B) or (IVc-B), or a mixture thereof:

[0127]

[0128] Each R 3 are alkyl groups and are independently selected to provide R having 12 to 22 carbon atoms 1 Group.

[0129] In some embodiments of the nitrogen-containing compound of formula (III), the A group is an acyclic nitrogen-containing group as described above, such as an amine or polyamine group. In such embodiments, the main component of the nitrogen-containing compound can be a cyclic imide, wherein R 2 is a bond to the A group, suitably to the amine group of the A group. Thus the nitrogen-containing compound may have formula (IIIb)

[0130]

[0131] Where R 1 As defined above.

[0132] In such an embodiment, the A group may be polyethyleneimine. Thus the nitrogen-containing compound may have formula (V):

[0133]

[0134] wherein n is 1 to 10. The nitrogen-containing compound may be a mixture of compounds having different values ​​of n in the "A" group. Thus n is suitably the average of the different values ​​of n present in the mixture. Thus n may be 1 to 10, i.e. a non-integer value of 1.0 to 10.0. Preferably, n is 1 to 6, 1 to 4 or 1 to 3.

[0135] In such embodiments, the nitrogen-containing compound may comprise a ring-opened analogue having formula (Vb):

[0136]

[0137] Where R 2 Preferably OH or O - X + , wherein X is a cation, such as a metal cation or an ammonium ion.

[0138] In such embodiments of the compounds of Formula (V) and / or (Vb), R 1 Preferred are hydrocarbyl groups having an Mn of 100 to 500, preferably 150 to 350 or 200 to 300.

[0139] For example, R 1 It may be a polyisobutylene or olefin having an Mn of 100 to 500, preferably 150 to 350 or 200 to 300.

[0140] In some embodiments, R 1 is a polyisobutylene group, so the nitrogen-containing compound has the formula (VA) and / or (Vb-A):

[0141]

[0142] wherein n is 1 to 10; and wherein m is 1 to 3. Preferably, n is 1 to 4 or 1 to 3. As described above, n and m may be average values, wherein there are mixtures of compounds containing different n and m values. Thus, n and m may be non-integer values ​​representing average values, such that n is 1.0 to 10.0 and m is 1.0 to 3.0.

[0143] In some embodiments, R 1 It is a C10-24 olefin group, preferably a C12-22 olefin group or a C16-18 olefin group. Therefore, the nitrogen-containing compound has the formula (VB) and / or the formula (Vb-B) or a mixture thereof:

[0144]

[0145] wherein n is from 1 to 10 and may be a non-integer average; and

[0146] Each R 3 are alkyl groups and are independently selected to provide R having 12 to 22 carbon atoms 1 Preferably, n is 1 to 4 or 1 to 3.

[0147] In some embodiments of the present invention, the nitrogen-containing compound is the reaction product of a) a hydrocarbyl-substituted reagent and b) a nitrogen-containing reagent, wherein a) is an amine or polyamine containing a hydrocarbyl group. In such embodiments, the nitrogen-containing compound may be the product of a Mannich reaction involving an aldehyde. Thus, the nitrogen-containing compound may be the reaction product of:

[0148] a) amines or polyamines containing hydrocarbon groups;

[0149] b) nitrogen-containing reagents; and

[0150] c) Aldehydes.

[0151] In such embodiments, as further described below, the hydrocarbyl group R 1 The link L between the nitrogen-containing group A is provided by a bond.

[0152] Suitably, component a) comprises a group R as defined above 1 Suitably, component a) is an alkylamine as defined above, preferably having the formula NHR 7 R 8 , where R 7 and R 8 Each is independently selected from H, an optionally substituted C1-20 alkyl group or an optionally substituted C1-20 alkenyl group. Therefore, component a) is preferably a dialkylamine. Preferably, R 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl. The alkyl may be branched, straight or cyclic, preferably branched or straight. Preferably, R 7 and R 8 The same and selected from C1-20 alkyl, preferably C2-20 alkyl.

[0153] Component a) may be selected from diethylamine, dipropylamine, dibutylamine, diamylamine, dihexylamine, bis(2-ethylhexyl)amine or dicocoalkylamine.

[0154] Component b) is preferably a nitrogen-containing reagent comprising a nitrogen-containing heterocycle. Preferably, component b) is selected from an optionally substituted five-membered nitrogen-containing heterocyclic compound or a benzo-fused five-membered nitrogen-containing heterocyclic compound. Preferably, component b) is selected from an optionally substituted triazole, tetrazole, indole, indazole or benzotriazole. Preferably, component b) is selected from triazole, tetrazole, indole, indazole or benzotriazole, preferably triazole, tetrazole or benzotriazole.

[0155] Component c) is suitably an aliphatic aldehyde. Preferably, the aldehyde has from 1 to 10 carbon atoms. Most preferably, the aldehyde is formaldehyde or a source of formaldehyde.

[0156] In a preferred embodiment, the nitrogen-containing compound is the reaction product of:

[0157] a) having the formula NHR 7 R 8 Alkylamine, where R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl;

[0158] b) a nitrogen-containing reagent selected from optionally substituted triazoles, tetrazoles, indoles, indazoles or benzotriazoles, and

[0159] c) Formaldehyde or a source of formaldehyde.

[0160] In such embodiments, the nitrogen-containing compound formed by the reaction of a), b), and c) may have the structure described below, for example, as the major component in the mixture of compounds produced by the reaction.

[0161] In some embodiments of the present invention, L of the nitrogen-containing compound of formula (I) may be a bond. In such embodiments, the nitrogen-containing compound may have formula (VI):

[0162]

[0163] in:

[0164] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0165] W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH, which are optionally substituted where appropriate; and

[0166] wherein the compound optionally comprises a cycloalkyl or aryl ring connecting Y and Z.

[0167] Therefore, in some embodiments, the nitrogen-containing compound used in the first and second aspects of the present invention is preferably of formula (VI).

[0168] R 1 The solubilizing group may be bonded to any suitable atom of the nitrogen-containing heterocyclic group. 1 Preferably, R 1 bonded to the nitrogen of the nitrogen-containing heterocyclic group.

[0169] In such an embodiment, R 1 Preference is given to aminoalkyl groups having a molecular weight (Mn) of up to 1,000. The aminoalkyl groups preferably have a molecular weight (Mn) of 50 to 500, preferably 50 to 350 or 50 to 300.

[0170] R 1May have the formula -CH 2 NR 7 R 8 , where R 7 and R 8 Each is independently selected from H, an optionally substituted C1-20 alkyl group or an optionally substituted C1-20 alkenyl group. 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl. The alkyl may be a branched or straight chain alkyl. Preferably, R 7 and R 8 are the same and are selected from C1-20 alkyl, preferably C2-20 alkyl. 7 and R 8 Each is independently selected from C1-12 alkyl, preferably C2-10 alkyl.

[0171] In some embodiments of the nitrogen-containing compound of formula (VI), the heterocyclic group is an optionally substituted five-membered nitrogen-containing heterocycle. In such embodiments, W, X, Y and Z are each independently selected from CH, C, N and NH. In such embodiments, the heterocyclic group is preferably selected from an optionally substituted triazole or tetrazole. For example, the nitrogen-containing compound may have formula (VII):

[0172]

[0173] Where R 7 and R 8 Each is independently selected from optionally substituted C1-20 alkyl, preferably optionally substituted C2-20 alkyl. 7 and R 8 Each is independently selected from optionally substituted C1-12 alkyl, preferably optionally substituted C2-10 alkyl.

[0174] The nitrogen-containing compound may have the formula (VIII) and / or (VIIIb) or a mixture thereof:

[0175]

[0176] Where R 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl. The nitrogen-containing compound may be a mixture of such compounds. For example, the nitrogen-containing compound may be a mixture of compounds of formula (VIII) and (VIIIb) in a ratio of 1:10 to 10:1, suitably 1:5 to 5:1.

[0177] In some embodiments of the nitrogen-containing compound of formula (VI), the heterocyclic group is an optionally substituted benzo-fused five-membered nitrogen-containing heterocyclic ring. In such embodiments, the nitrogen-containing compound has formula (IX):

[0178]

[0179] in:

[0180] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0181] W and X are each independently selected from C and N; and

[0182] Each R 6 Independently selected from H, C1-6 alkyl or C1-6 alkenyl.

[0183] Preferably, each R 6 It's H.

[0184] In such an embodiment, R 1 Preference is given to aminoalkyl groups having a molecular weight (Mn) of up to 1,000. The aminoalkyl groups preferably have a molecular weight (Mn) of 50 to 500, preferably 50 to 350 or 50 to 300.

[0185] As mentioned above, R 1 Preferably, the compound has the formula -CH 2 NR 7 R 8 , where R 7 and R 8 Each is independently selected from H, an optionally substituted C1-20 alkyl group or an optionally substituted C1-20 alkenyl group. 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl. The alkyl may be branched, straight or cyclic, preferably branched or straight. Preferably, R 7 and R 8 The same and selected from C1-20 alkyl, preferably C2-20 alkyl.

[0186] The nitrogen-containing compound may therefore have the formula (X):

[0187]

[0188] in:

[0189] W and X are each independently selected from C and N;

[0190] Each R 6 independently selected from H, C1-6 alkyl or C1-6 alkenyl; and

[0191] R 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl.

[0192] In some embodiments, the nitrogen-containing heterocycle is an optionally substituted benzotriazole, and the nitrogen compound has the formula (XI):

[0193]

[0194] in:

[0195] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0196] Each R 6 Independently selected from H, C1-6 alkyl or C1-6 alkenyl.

[0197] In a preferred embodiment, the nitrogen compound has the formula (XII):

[0198]

[0199] in:

[0200] Each R 6 independently selected from H, C1-6 alkyl or C1-6 alkenyl; and

[0201] R 7 and R 8 Each is independently selected from C1-20 alkyl, preferably C2-20 alkyl.

[0202] The nitrogen-containing compound used in the first and second aspects of the present invention may be present in an additive composition. The additive composition may contain other components in addition to the nitrogen-containing compound. For example, the additive composition may include a solvent and / or other fuel additives as further described below.

[0203] The present invention may thus provide the use of an additive composition comprising a nitrogen-containing compound as an additive in a diesel fuel composition to reduce the effects of deposits in an EGR system of a diesel engine when the diesel fuel composition is combusted, wherein the nitrogen-containing compound comprises at least 4 mass % nitrogen atoms.

[0204] Similarly, the present invention may provide a method of reducing the effects of deposits in an EGR system of a diesel engine, the method comprising combusting in the engine a diesel fuel composition comprising an additive composition, wherein the additive composition comprises a nitrogen-containing compound containing at least 4 mass % nitrogen atoms.

[0205] Preferably, the additive composition comprises at least 20 wt% of said nitrogen-containing compound, preferably at least 30 wt% or at least 45 wt% of said nitrogen-containing compound.

[0206] In such embodiments it may be convenient to refer to the mass % of nitrogen atoms of the total additive composition. The nitrogen content of the additive composition is suitably provided in large part by nitrogen containing compounds. Preferably the additive composition comprises at least 5 mass % nitrogen atoms, preferably at least 6% or at least 7%.

[0207] Suitably, the additive composition comprises up to 35 mass % nitrogen atoms, suitably up to 30% or up to 25%.

[0208] In a preferred embodiment the additive composition comprises from 4 to 35 mass % nitrogen atoms, suitably 5 to 30 % or 6 to 25 %.

[0209] In such embodiments, the additive composition can be a direct product of a reaction for forming a nitrogen-containing compound. Due to the reaction for forming a nitrogen-containing compound, such a direct product may contain other components. The additive composition may therefore contain a solvent, such as a relatively low volatility solvent, by-products of the reaction, unreacted starting materials, and isomers and analogs of the nitrogen-containing compound formed in the reaction. The reaction can be as described above, i.e., a reaction of components a) and b) or a reaction of components a), b) and c).

[0210] In some embodiments, the additive composition may contain additional components that are subsequently added to the reaction to form the nitrogen-containing compound. For example, the additive composition may include additional solvents or additional fuel additives as described in more detail below.

[0211] In summary, the nitrogen-containing compound used in the first and second aspects of the present invention is preferably the reaction product of the following ingredients:

[0212] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0213] b) nitrogen-containing reagents;

[0214] or the reaction product of:

[0215] a) amines or polyamines containing hydrocarbon groups;

[0216] b) nitrogen-containing reagents; and

[0217] c) Aldehydes.

[0218] The nitrogen-containing compound used in the first and second aspects of the present invention is preferably a reaction product of:

[0219] a) a hydrocarbyl-substituted carboxylic acylating agent; and

[0220] b) nitrogen-containing reagents;

[0221] Having formula (III):

[0222]

[0223] in:

[0224] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0225] R 2 OH, NH 2 , OR 4 ,OM,NHR 4 or NR 4 R 5 , or a bond to A, wherein M is a cation, preferably an alkali metal cation or an ammonium cation, and wherein R 4 and R 5 are independently selected from optionally substituted C1-6 alkyl or alkenyl groups, and may independently contain a quaternary ammonium group;

[0226] or the reaction product of:

[0227] a) amines or polyamines containing hydrocarbon groups;

[0228] b) nitrogen-containing reagents; and

[0229] c) aldehydes;

[0230] Having formula (VI):

[0231]

[0232]

[0233] in:

[0234] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0235] W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH; and

[0236] wherein the compound optionally comprises a cycloalkyl or aryl ring connecting Y and Z.

[0237] The nitrogen-containing compound used in the first and second aspects of the present invention is suitably of formula (I):

[0238] ALR 1

[0239] (I)

[0240] in:

[0241] A is a nitrogen-containing group;

[0242] L is a bond or a linker; and

[0243] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0244] Where A is selected from:

[0245] 1) optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, a five-membered heterocyclic ring such as pyrazole or imidazole, or a benzo-fused five-membered heterocyclic ring such as benzimidazole; or

[0246] 2) an acyclic nitrogen-containing group having formula (II):

[0247]

[0248] Wherein n is 1 to 10.

[0249] The nitrogen-containing compound used in the first and second aspects of the present invention preferably has the formula (III):

[0250]

[0251] in:

[0252] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000; and

[0253] R 2 OH, NH 2 , OR 4 ,OM,NHR 4 or NR 4 R 5 , or a bond to A, wherein M is a cation, preferably an alkali metal cation or an ammonium cation, and wherein R 4 and R 5 are independently selected from optionally substituted C1-6 alkyl or alkenyl, and R 4 and R 5 may independently contain quaternary ammonium groups;

[0254] Or having formula (VI):

[0255]

[0256] in:

[0257] R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000;

[0258] W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH; and

[0259] The compound optionally comprises a cycloalkyl or aryl ring connecting Y and Z.

[0260] Suitably, the nitrogen containing compound is present in the diesel fuel composition in an amount of at least 1 ppm, preferably at least 10 ppm, more preferably at least 20 ppm, suitably at least 30 ppm, preferably at least 40 ppm, for example at least 50 ppm or at least 60 ppm.

[0261] Suitably, the nitrogen containing compound is present in the diesel fuel composition in an amount of at most 10000 ppm, preferably at most 9000 ppm, suitably at most 8000 ppm, for example at most 7000 ppm.

[0262] In some preferred embodiments, the nitrogen containing compound is present in the diesel fuel composition in an amount less than 1000 ppm, preferably less than 700 ppm, more preferably less than 500 ppm, suitably less than 400 ppm, for example less than 350 ppm or less than 300 ppm.

[0263] In some embodiments, the nitrogen-containing compound is present in the diesel fuel composition in an amount of 50 to 6000 ppm.

[0264] In some embodiments, the nitrogen-containing compound is present in the diesel fuel composition in an amount of 50 to 3000 ppm, more preferably 50 to 2000 ppm.

[0265] In some embodiments, the nitrogen-containing compound is present in the diesel fuel composition in an amount of 50 to 750 ppm.

[0266] Preferably, the nitrogen containing compound is present in the diesel fuel composition in an amount of from 50 to 350 ppm.

[0267] In some particularly preferred embodiments, the nitrogen-containing compound is present in the diesel fuel composition in an amount of 50 to 300 ppm.

[0268] In this specification any reference to ppm is parts per million by weight.

[0269] The diesel fuel composition used in the present invention may comprise a mixture of two or more nitrogen-containing compounds.In such embodiments, the above amounts refer to the total amount of all such additives present in the composition.

[0270] The nitrogen-containing compound can be added to the diesel fuel at any convenient location in the supply chain. For example, the additive can be added to the fuel at a refinery, at a distribution terminal, or after the fuel has left the distribution terminal. If the additive is added to the fuel after it has left the distribution terminal, this is called an aftermarket application. Aftermarket applications include situations such as adding the additive to the fuel in a delivery tanker, directly to a customer's bulk storage tank, or directly to an end user's vehicle tank. Aftermarket applications can include supplying the fuel additive in a small bottle suitable for adding directly to a fuel storage tank or a vehicle tank.

[0271] Diesel fuel includes any fuel suitable for use in a diesel engine whether on-road or off-road. This includes, but is not limited to, fuels described as diesel, marine diesel, heavy fuel oil, industrial fuel oil, and the like.

[0272] The diesel fuel composition used in the present invention may comprise a petroleum-based fuel oil, especially a middle distillate fuel oil. Such distillate fuel oils typically boil in the range of 110° C. to 500° C., for example 150° C. to 400° C. The diesel fuel may comprise atmospheric or vacuum distillates, cracked gas oils, or a blend of any proportions of straight run fractions and refinery streams such as thermal and / or catalytic cracking and hydrocracking distillates.

[0273] The diesel fuel composition may comprise non-renewable Fischer-Tropsch fuels such as those described as GTL (gas-to-liquid) fuels, CTL (coal-to-liquid) fuels and OTL (oil sands-to-liquid).

[0274] The diesel fuel composition may comprise a renewable fuel, such as a biofuel composition or a biodiesel composition.

[0275] Diesel fuel compositions may include first generation biodiesel. First generation biodiesel contains, for example, vegetable oils, animal fats and esters of used cooking fats or oils. This form of biodiesel can be obtained by transesterification of oils, for example rapeseed oil, soybean oil, canola oil, safflower oil, palm oil, corn oil, peanut oil, cottonseed oil, tallow, coconut oil, jatropha oil, sunflower oil, used cooking oils, hydrogenated vegetable oils or any mixture thereof with alcohols, usually monoalcohols, usually in the presence of a catalyst.

[0276] The diesel fuel composition may include second generation biodiesel. Second generation biodiesel is derived from renewable resources, such as vegetable oils and animal fats, and is typically treated in a refinery using, for example, hydroprocessing, such as the H-Bio process developed by Petrobras. Second generation biodiesel may be similar in nature and quality to petroleum-based fuel oil streams, such as renewable diesel prepared from vegetable oils, animal fats, etc. and sold by ConocoPhillips as Renewable Diesel and by Neste as NExBTL.

[0277] The diesel fuel composition may comprise third generation biodiesel. Third generation biodiesel utilizes gasification and Fischer-Tropsch technology, including those described as BTL (biomass-to-liquid) fuels. Third generation biodiesel is not much different from some second generation biodiesels, but is intended to utilize whole plants (biomass) and thereby broaden the feedstock base.

[0278] In some embodiments, the diesel fuel composition may include a pyrolysis oil, such as a plastic pyrolysis oil or a biomass (wood, vegetable oil, algae) pyrolysis oil.

[0279] The diesel fuel composition may contain a blend of any or all of the above diesel fuel compositions.

[0280] In some embodiments, the diesel fuel composition can be a blended diesel fuel comprising biodiesel. In such a blend, biodiesel can exist in an amount of, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 99% at the most.

[0281] In some embodiments, the fuel composition may comprise neat biodiesel.

[0282] In some preferred embodiments, the fuel composition comprises at least 5 wt.% biodiesel.

[0283] In some embodiments, the fuel composition may include a GTL fuel or be a neat GTL fuel.

[0284] In some embodiments, the diesel fuel composition may contain a secondary fuel, such as ethanol. However, the diesel fuel composition preferably does not contain ethanol.

[0285] The diesel fuel composition for use in the present invention may contain a relatively high sulphur content, for example greater than 0.05% by weight, such as 0.1% or 0.2%.

[0286] However, in a preferred embodiment, the diesel fuel composition has a sulfur content of at most 0.05 wt%, more preferably at most 0.035 wt%, especially at most 0.015%. Fuels with lower sulfur contents are also suitable, such as fuels with less than 50 wt ppm sulfur, preferably less than 20 ppm, for example 10 ppm or less sulfur.

[0287] The diesel fuel composition for use in the present invention preferably comprises at least 5 wt% biodiesel and less than 50 ppm sulphur.

[0288] Various metal species may be present in diesel fuel compositions. This may be due to contamination of the fuel during manufacture, storage, transportation or use or due to contamination of fuel additives. Metal species may also be intentionally added to the fuel. For example, transition metals are sometimes added as fuel borne catalysts, for example to improve the performance of diesel particulate filters.

[0289] Other metal-containing species may also be present as contaminants, for example due to corrosion of metal and metal oxide surfaces by acidic species present in the fuel or from lubricating oils. In use, fuels such as diesel fuels routinely come into contact with metal surfaces in, for example, vehicle fuel supply systems, fuel tanks, fuel transportation vehicles, etc. Typically, metal-containing contaminants may include transition metals such as zinc, iron, and copper; Group I or Group II metals and other metals such as lead.

[0290] In addition to metal-containing contaminants that may be present in diesel fuel, metal-containing species may be intentionally added to the fuel in some cases. For example, metal-containing fuel-borne catalyst species may be added to assist in the regeneration of a particulate trap, as is known in the art. The presence of such catalysts may also cause injector deposits when the fuel is used in a diesel engine with a high pressure EGR system.

[0291] Metal-containing contaminants, depending on their source, may be in the form of insoluble particles or soluble compounds or complexes. Metal-containing fuel-borne catalysts are usually soluble compounds or complexes or colloidal species.

[0292] In some embodiments, the diesel fuel may contain a metal-containing species comprising a fuel-borne catalyst. Preferably, the fuel-borne catalyst comprises one or more metals selected from iron, cerium, platinum, manganese, Group I and Group II metals (e.g., calcium and strontium). The fuel-borne catalyst most preferably comprises a metal selected from iron and cerium.

[0293] Typically, the total amount of all metal-containing species in the diesel fuel, expressed as the total weight of metals in the species, is from 0.1 to 50 ppm by weight, such as from 0.1 to 20 ppm, preferably from 0.1 to 10 ppm by weight, based on the weight of the diesel fuel.

[0294] Diesel fuel compositions for the present invention may include one or more additional additives, such as those common in diesel fuels. These include, for example, antioxidants, dispersants, detergents, metal deactivation compounds, wax anti-settling agents, low temperature flow improvers, cetane number improvers, dehazers, stabilizers, demulsifiers, defoamers, corrosion inhibitors, lubricity improvers, dyes, markers, combustion improvers, metal passivators, odor masking agents, drag reducers and conductivity improvers. The examples of the appropriate amounts of these types of additives are known to those skilled in the art.

[0295] Suitable cetane number improvers may be selected from C2-24 alkyl nitrates and dialkyl peroxides, preferably decyl nitrate, 2-ethylhexyl nitrate and di-tert-butyl peroxide. Such cetane number improvers are suitably used in a concentration of 50-6,000 ppm, preferably 50-750 ppm, based on the diesel fuel composition.

[0296] In some preferred embodiments, the diesel fuel compositions of the present invention comprise one or more detergents. Nitrogen-containing detergents are preferred.

[0297] The one or more detergents may be selected from:

[0298] (i) quaternary ammonium salt additives;

[0299] (ii) products of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol;

[0300] (iii) the reaction product of a carboxylic acid derived acylating agent and an amine;

[0301] (iv) the reaction product of a carboxylic acid derived acylating agent and hydrazine;

[0302] (v) salts formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine;

[0303] (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine compound or salt, said product comprising at least one aminotriazole group; and

[0304] (vii) Replacement of polycyclic aromatic hydrocarbon detergent additives.

[0305] Preferably, the one or more detergents are selected from one or more of the following:

[0306] (i) quaternary ammonium salt additives;

[0307] (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and

[0308] (iii) The reaction product of a carboxylic acid derived acylating agent and an amine.

[0309] The ratio of nitrogen-containing compound to detergent is suitably from 5:1 to 1:5, preferably from 2:1 to 1:2.

[0310] In some embodiments, the diesel fuel composition further comprises (i) a quaternary ammonium salt additive.

[0311] The quaternary ammonium salt additive is suitably the reaction product of a nitrogen-containing species having at least one tertiary amine group and a quaternising agent.

[0312] The nitrogen-containing species may be selected from:

[0313] (x) the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine, secondary amine or alcohol group;

[0314] (y) a Mannich reaction product comprising a tertiary amine group; and

[0315] (z) Polyalkylene-substituted amines having at least one tertiary amine group.

[0316] Examples of quaternary ammonium salts and methods of making them are described in the following patents, which are incorporated herein by reference: US2008 / 0307698, US2008 / 0052985, US2008 / 0113890, and US2013 / 031827.

[0317] The preparation of some suitable quaternary ammonium salt additives wherein the nitrogen-containing species comprises component (x) is described in WO 2006 / 135881 and WO 2011 / 095819.

[0318] Component (y) is a Mannich reaction product with a tertiary amine. The preparation of quaternary ammonium salts formed from nitrogen-containing species including component (y) is described in US 2008 / 0052985.

[0319] The preparation of quaternary ammonium salt additives in which the nitrogen-containing species comprises component (z) is described, for example, in US 2008 / 0113890.

[0320] To form the quaternary ammonium salt additive (i), a nitrogen-containing species having a tertiary amine group is reacted with a quaternizing agent.

[0321] The quaternizing agent may suitably be selected from esters and non-esters.

[0322] Preferred quaternizing agents for use herein include dimethyl oxalate, methyl 2-nitrobenzoate, methyl salicylate and styrene oxide, or propylene oxide optionally in combination with an additional acid.

[0323] One particularly preferred additional quaternary ammonium salt for use herein is formed by reacting the reaction product of a polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight of 700 to 1300 and dimethylaminopropylamine with methyl salicylate or dimethyl oxalate.

[0324] Other suitable quaternary ammonium salts include quaternized terpolymers such as described in US2011 / 0258917; quaternized copolymers such as described in US2011 / 0315107; and acid-free quaternized nitrogen compounds disclosed in US2012 / 0010112.

[0325] Further suitable quaternary ammonium compounds for use in the present invention include the quaternary ammonium compounds described in the applicant's co-pending applications WO2011095819, WO2013 / 017889, WO2015 / 011506, WO2015 / 011507, WO2016 / 016641 and PCT / GB2016 / 052312.

[0326] In some embodiments, the diesel fuel composition used in the present invention comprises 1 to 500 ppm, preferably 50 to 250 ppm of the quaternary ammonium salt additive (i).

[0327] In some embodiments, the diesel fuel composition further comprises (ii) a product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol. This Mannich reaction product is suitably not a quaternary ammonium salt.

[0328] Preferably, the aldehyde component used to prepare the Mannich additive is an aliphatic aldehyde. The aldehyde preferably has 1 to 10 carbon atoms. The aldehyde is most preferably formaldehyde.

[0329] Suitable amines for preparing Mannich additives include monoamines and polyamines. One suitable monoamine is butylamine.

[0330] The amine used to prepare the Mannich additive is preferably a polyamine. This can be selected from any compound comprising two or more amine groups. The polyamine is preferably a polyalkylene polyamine, preferably a polyethylene polyamine. The polyamine most preferably comprises tetraethylenepentamine or ethylenediamine.

[0331] The optionally substituted phenol component used to prepare the Mannich additive may be substituted on the aromatic ring by 0 to 4 groups (in addition to the phenolic OH). For example, it can be a hydrocarbyl-substituted cresol. The phenol component is most preferably a monosubstituted phenol. It is preferably a hydrocarbyl-substituted phenol. Preferred hydrocarbyl substituents are alkyl substituents having 4 to 28 carbon atoms, especially 10 to 14 carbon atoms. Another preferred hydrocarbyl substituent is a polyalkenyl substituent. Such a polyisobutylene substituent has a number average molecular weight of 400 to 2500, for example 500 to 1500.

[0332] In some embodiments, the diesel fuel composition of the present invention comprises from 1 to 500 ppm, preferably from 50 to 250 ppm of the Mannich additive (ii).

[0333] In some embodiments, the diesel fuel composition further comprises (iii) the reaction product of a carboxylic acid derived acylating agent and an amine.

[0334] These may also be generally referred to herein as acylated nitrogen-containing compounds.

[0335] Suitable acylated nitrogen-containing compounds can be prepared by reacting a carboxylic acid acylating agent with an amine and are known to those skilled in the art.

[0336] The preferred hydrocarbyl substituted acylating agent is polyisobutenyl succinic anhydride.These compounds are often referred to as "PIBSA" and are known to those skilled in the art.

[0337] Conventional polyisobutylenes and so-called "highly reactive" polyisobutylenes are suitable for use in the present invention.

[0338] Particularly preferred PIBSAs are those having a PIB molecular weight (Mn) of 300 to 2800, preferably 450 to 2300, more preferably 500 to 1300.

[0339] In a preferred embodiment, the reaction product of a carboxylic acid derived acylating agent and an amine includes at least one primary or secondary amine group.

[0340] Preferred acylated nitrogen compounds for use herein are prepared by reacting a poly(isobutylene) substituted succinic acid derived acylating agent (e.g., anhydride, acid, ester, etc.), wherein the poly(isobutylene) substituent has a number average molecular weight (Mn) between 170 and 2800, with a mixture of ethylene polyamines having from 2 to about 9 amino nitrogen atoms, preferably from about 2 to about 8 nitrogen atoms, and from about 1 to about 8 ethylene groups per ethylene polyamine. These acylated nitrogen compounds are suitably formed by reacting an acylating agent:amino compound in a molar ratio of 10:1 to 1:10, preferably 5:1 to 1:5, more preferably 2:1 to 1:2, and most preferably 2:1 to 1:1. In a particularly preferred embodiment, the acylated nitrogen compound is formed by reacting an acylating agent to an amino compound in a molar ratio of 1.8:1 to 1:1.2, preferably 1.6:1 to 1:1.2, more preferably 1.4:1 to 1:1.1, and most preferably 1.2:1 to 1:1. Acylated amino compounds of this type and their preparation are well known to the person skilled in the art and are described, for example, in EP 0 565 285 and US Pat. No. 5,925,151.

[0341] In some preferred embodiments, the composition comprises a detergent of the type formed by the reaction of a polyisobutylene-substituted succinic acid-derived acylating agent and a polyethylene polyamine. Suitable compounds are described, for example, in WO2009 / 040583.

[0342] In some embodiments, the diesel fuel composition of the present invention comprises from 1 to 500 ppm, preferably from 50 to 250 ppm of an additive (iii) which is a reaction product of an acylating agent and an amine.

[0343] In some embodiments, the diesel fuel composition comprises (iv) the reaction product of a carboxylic acid derived acylating agent and hydrazine.

[0344] Suitably, the additive comprises the reaction product between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine.

[0345] Preferably, the hydrocarbyl group of the hydrocarbyl-substituted succinic acid or anhydride comprises C 8 -C 36 Group, preferably C 8 -C 18 Alternatively, the hydrocarbon group may be a polyisobutylene group having a number average molecular weight between 200 and 2500, preferably between 800 and 1200.

[0346] Hydrazine has the formula NH 2 -NH 2 The hydrazine may be hydrated or non-hydrated. Monohydrated hydrazine is preferred.

[0347] As disclosed in US 2008 / 0060259, the reaction between a hydrocarbyl-substituted succinic acid or anhydride and hydrazine produces a variety of products.

[0348] In some embodiments, the diesel fuel composition further comprises (v) a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine. Exemplary compounds of this type are described in US 2008 / 0060608.

[0349] Such additives may suitably be of the formula [R'(COOH) X ] y' The di-n-butylamine or tri-n-butylamine salt of a fatty acid wherein each R' is independently a hydrocarbon group of 2 to 45 carbon atoms, and x is an integer between 1 and 4.

[0350] In a preferred embodiment, the carboxylic acid comprises tall oil fatty acid (TOFA).

[0351] Further preferred features of additives of this type are described in EP1900795.

[0352] In some embodiments, the diesel fuel composition further comprises (vi) a reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine compound or salt, said product comprising at least one aminotriazole group.

[0353] Further preferred features of additive compounds of this type are as specified in US 2009 / 0282731.

[0354] In some embodiments, the diesel fuel composition further comprises (vii) a substituted polycyclic aromatic hydrocarbon detergent additive.

[0355] A preferred compound of this type is the reaction product of ethoxylated naphthol and paraformaldehyde which is then reacted with a hydrocarbyl-substituted acylating agent.

[0356] Further preferred features of these detergents are described in EP1884556.

[0357] The present invention suitably reduces the formation of deposits in the EGR system of a diesel engine.

[0358] Most preferably, the engine is a direct injection diesel engine.

[0359] The nitrogen-containing compounds used in the present invention have been found to be particularly effective in modern diesel engines having high pressure fuel systems.

[0360] Suitably, the present invention may be used to reduce the formation of deposits in an EGR system of a diesel engine having a high pressure fuel system. Suitably, the diesel engine has a pressure in excess of 1350 bar (1.35 x 10 8 Pa) of fuel pressure. It can have a maximum of 2000 bar (2 x 10 8 Pa) or higher pressure.

[0361] Such a diesel engine can be characterized in many ways.

[0362] Such engines are typically equipped with fuel injection equipment that meets or exceeds "Euro 5" emissions regulations or equivalent regulations in the United States or other countries.

[0363] Such engines are typically equipped with a fuel injector having a plurality of orifices, each orifice having an inlet and an outlet.

[0364] Such engines may feature a tapered orifice such that the injection hole has an entrance diameter that is larger than the exit diameter.

[0365] Such modern engines may feature orifices having an outlet diameter of less than 500 μm, preferably less than 200 μm, more preferably less than 150 μm, preferably less than 100 μm, most preferably less than 80 μm or less.

[0366] Such modern diesel engines may feature an aperture in which the inner edge of the inlet is circular.

[0367] Such modern diesel engines may feature an injector having more than one orifice, suitably more than 2 orifices, preferably more than 4 orifices, for example 6 or more orifices.

[0368] Such modern diesel engines may be characterized by operating tip temperatures in excess of 250°C.

[0369] Such modern diesel engines may feature a fuel injection system providing a fuel pressure of greater than 1350 bar, preferably greater than 1500 bar, more preferably greater than 2000 bar.

[0370] Two non-limiting examples of such high pressure fuel systems are: a common rail injection system, in which the fuel is compressed using a high pressure pump, which supplies the fuel to the fuel injection valves via the common rail; and a unit injection system, which integrates the high pressure pump and the fuel injection valves in one assembly to achieve pressures in excess of 2000 bar (2 x 10 8 In both systems, as the fuel is pressurized it becomes hot, typically to temperatures of about 100°C or more.

[0371] Preferably, the diesel engine has a fuel injection system comprising a common rail injection system.

[0372] In a common rail system, the fuel is stored at high pressure in a central accumulator rail or in a separate accumulator before being delivered to the injectors. Some of the heated fuel is usually returned to the low pressure side of the fuel system or to the fuel tank. In a unit injection system, the fuel is compressed within the injector to generate a high injection pressure. This in turn increases the temperature of the fuel.

[0373] In both systems, the fuel is present in the injector body before injection, where it is further heated due to the heat from the combustion chamber. The fuel temperature at the injector tip can be as high as 250-350°C.

[0374] Therefore, the fuel is injected at 1350 bar (1.35 x 10 8 Pa) to over 2000 bar (2x10 8 The fuel is stressed at pressures of approximately 100°C to 350°C and is sometimes recirculated back within the fuel system, thereby increasing the time the fuel is subjected to these conditions.

[0375] The EGR system recirculates exhaust gas to reduce the oxygen concentration in the combustion chamber. This reduces NO x Gas generation.

[0376] The EGR system includes a cooler. This component reduces the temperature of the recirculated exhaust gas.

[0377] Exhaust gases enter the EGR system after they have passed through or are generated in the combustion chamber. The exhaust gases may contain materials resulting from incomplete combustion. These materials may be deposited within the EGR system. One component where deposit accumulation often occurs is in the cooler of the EGR system.

[0378] These deposits have not been previously studied in the same detail as other fuel system or combustion deposits. In fact, the discovery of these deposits appears to be a relatively recent phenomenon. A particularly rich review of the work done to elucidate how they form and why they are a problem can be found in Lance et al., International Journal of Heat and Mass Transfer 126, (2018), 509-520 and SAE 2014-01-0629.

[0379] The present inventors have investigated the nature of deposits found in EGR systems, in particular in the cooler. It has surprisingly been found that the formation of these deposits can be particularly reduced by adding one or more nitrogen-containing compounds to the diesel fuel combusted in the engine.

[0380] The use of the first aspect and / or the method of the second aspect may relate to reducing the effects of deposits in an exhaust gas recirculation system of a diesel engine, the exhaust gas recirculation system being a high pressure, low pressure, hybrid or dedicated EGR system. Suitably, the exhaust gas recirculation system is a high pressure, hybrid or dedicated EGR system. Preferably, the exhaust gas recirculation system is a high pressure system. The high pressure EGR may be a stand-alone high pressure EGR system, or part of a hybrid or dedicated EGR system.

[0381] Preferably, the use or method of the invention reduces the formation of deposits in a high pressure EGR system of a diesel engine.

[0382] Reducing deposit formation in an EGR system means that when a fuel including the EGR deposit reducing additive is combusted in an engine, reduced deposit levels are achieved compared to when an otherwise identical fuel except for including the EGR deposit reducing additive is combusted under the same conditions.

[0383] Suitably, adding the one or more nitrogen containing compounds to a diesel fuel combusted in an engine reduces deposit formation in the EGR system by at least 5%, preferably at least 10%, for example at least 15% or at least 20%.

[0384] In some embodiments, adding the one or more nitrogen-containing compounds to a diesel fuel combusted in an engine can reduce deposit formation in the EGR system by at least 30%, such as at least 40% or at least 50%.

[0385] Suitably, adding the one or more nitrogen containing compounds to a diesel fuel combusted in an engine reduces deposit formation in the cooler of the EGR system by at least 5%, preferably at least 10%, for example at least 15% or at least 20%.

[0386] In some embodiments, adding the one or more nitrogen-containing compounds to a diesel fuel combusted in an engine can reduce deposit formation in a cooler of an EGR system by at least 30%, such as at least 40% or at least 50%.

[0387] The reduction of deposits in the EGR system may be measured by any suitable means.

[0388] One simple means by which the deposit level in an EGR system can be determined is to weigh the system before and after use.One or more parts of the system may be weighed.

[0389] Preferably, the present invention reduces the total amount of deposits formed in the EGR system by at least 5%, preferably at least 10%, more preferably at least 15%, for example at least 20% or at least 30%.

[0390] Suitably, the present invention reduces the amount of deposits that form within a cooler of an EGR system.

[0391] Preferably, the present invention reduces the total amount of deposits formed in the cooler of the EGR system by at least 5%, preferably at least 10%, more preferably at least 15%, for example at least 20% or at least 30%.

[0392] The deposits formed in the EGR system can be analyzed. This can be achieved, for example, by extracting the deposits or a portion thereof into a solvent. The sample can be separated into soluble and insoluble fractions; these can then be analyzed separately by methods known to those skilled in the art, such as elemental analysis, thermogravimetric analysis and / or gas chromatography-mass spectrometry.

[0393] The deposits formed in the EGR system can be analyzed, for example, by thermogravimetric analysis (TGA). It was found that a large portion of the deposits formed on the cooler of the EGR system are carbonaceous deposits, which degrade at temperatures between 400 and 540°C when subjected to thermogravimetric analysis (TGA).

[0394] Thermogravimetric analysis (or TGA) involves measuring the mass of a sample over time as it is heated. Such techniques are well known to those skilled in the art, and the selection of appropriate methods and suitable equipment is within the capabilities of those skilled in the art.

[0395] Any feature of the invention may be combined with any other feature as appropriate.

[0396] According to a third aspect of the present invention, there is provided a fuel additive composition comprising one or more nitrogen-containing compounds and a detergent additive, wherein the nitrogen-containing compound comprises at least 4 mass % of nitrogen atoms.

[0397] The nitrogen-containing compound of the fuel additive composition of the third aspect may have any suitable features and advantages described above with respect to the nitrogen-containing compounds used in the first and second aspects.

[0398] The detergent additive is suitably as described above in relation to the first and second aspects.

[0399] According to a fourth aspect of the present invention, there is provided a diesel fuel composition comprising one or more nitrogen-containing compounds and a detergent additive, wherein the nitrogen-containing compound comprises at least 4 mass % nitrogen atoms.

[0400] The nitrogen-containing compound and detergent additive of the fourth aspect are as described above in relation to the first, second and third aspects of the invention.

[0401] The diesel fuel composition of the fourth aspect may have any suitable features described above in relation to the first and second aspects.

[0402] The diesel fuel composition of the fourth aspect may comprise one or more additional additives selected from antioxidants, dispersants, detergents, metal deactivation compounds, wax anti-settling agents, cold flow improvers, cetane improvers, dehazers, stabilizers, demulsifiers, defoamers, corrosion inhibitors, lubricity improvers, dyes, markers, combustion improvers, metal deactivators, odor masking agents, drag reducers and conductivity improvers.

[0403] In some embodiments of the fuel additive composition of the third aspect or the diesel fuel composition of the fourth aspect, the detergent additive is:

[0404] the reaction product of a carboxylic acid derived acylating agent and an amine is the reaction product of tetraethylenepentamine (TEPA) and a PIBSA having a PIB number average molecular weight (Mn) of 300 to 2800; or

[0405] A quaternary ammonium salt formed by reacting the reaction product of dimethylaminopropylamine and a polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight (Mn) of 700 to 1300 with methyl salicylate or dimethyl oxalate; or a mixture thereof.

[0406] The invention will now be further described with reference to the following non-limiting examples. In the following examples, the values ​​given for treat rates in parts per million (ppm) refer to the amount of active agent, not the amount of formulation containing the active agent when added. All parts per million are by weight. Example

[0407] An exemplary nitrogen-containing compound for use as an additive in a diesel fuel composition according to the present invention is prepared as follows.

[0408] Example 1 - PIB 260 SA 5-Amino-[1H]-tetrazolyl reaction products

[0409] Main components:

[0410]

[0411] The nitrogen-containing compound of Example 1 was prepared as follows. A highly reactive grade of 260 number average molecular weight highly reactive (HR) poly(isobutylene) (PIB 260 ) and maleic anhydride (MA) to provide poly(isobutylene) succinic anhydride (PIB 260 SA) samples. PIB 260 The SA moiety was characterized by titration against lithium methoxide and was found to have 2.38 mmol.g -1 activity.

[0412] Loading PIB into the reactor 260 A sample of SA (135.01 g, 321.3 mmol) and Caromax20 solvent (162.3 g) were added and heated to 90°C. 5-amino-[1H]-tetrazole monohydrate (33.10 g, 321.1 mmol) was added and the contents of the flask were heated to above 100°C for 1 hour. The temperature was then increased to achieve an internal temperature of 170°C to promote the formation of amides. The progress of the reaction was monitored using ATR-FTIR.

[0413] The nitrogen content of three substantially identically prepared samples was determined by analysis using a Leco Flash 1112 series analyzer and found to be 6.45 to 6.53 wt %. The theoretical nitrogen content of the target compound is 15.1 to 17.2 wt %.

[0414] Example 2-C 16 / C 18 ASA 5-amino-[1H]-tetrazolyl reaction product

[0415] Main components:

[0416]

[0417] Where R 3 The total number of groups is C 13 H 28 or C 15 H 32 or a mixture thereof.

[0418] The nitrogen-containing compound of Example 2 was prepared as follows. The activity of a sample of Pentasize 68 (commercially available C16 to C18 alkenyl succinic anhydride (ASA)) was determined by lithium methoxide titration to be 2.97 mmol.g -1 The reaction flask was charged with 16.86 g (50 mmol active) in the highly aromatic solvent Innosol PP (20.256 g). 5-Amino-[1H]-tetrazole monohydrate (5.164 g, 50 mmol) was added and stirred to form a dispersion.

[0419] The dispersion was heated to a final internal temperature of 170° C. using a thermostatically controlled oil bath. The progress of the reaction was monitored at intervals using ATR-FTIR spectroscopy. The product contained approximately 50% by weight of the C16 / C18 ASA 5-amino-[1H]-tetrazolyl reaction product. The theoretical nitrogen content of the target compound was 16.1 to 17.8% by weight.

[0420] Example 3 - Imides from the reaction of C16 / C18 ASA with tetraethylenepentamine (TEPA)

[0421] Main components:

[0422]

[0423] Where R 3 The total number of groups is C 13 H 28 or C 15 H 32 or a mixture thereof.

[0424] The nitrogen-containing compound of Example 3 was prepared as follows. The activity of a sample of Pentasize 68 (commercially available C16 to C18 alkenyl succinic anhydride (ASA)) was determined by lithium methoxide titration to be 2.97 mmol.g -1 The reaction flask was charged with 150.02 g (446 mmol active) of Pentasize 68 and 2-ethylhexan-1-ol solvent (234.09 g). The pressure-equalized dropping funnel was charged with TEPA (84.40 gg, 446 mmol, 1.0 mole / anhydride group). The flask contents were warmed in an oil bath controlled by a thermostat set at 70°C. The oil bath set point was raised to 175°C and the reactor contents were allowed to warm.

[0425] The progress of the reaction was monitored at regular intervals using ATR-FTIR spectroscopy. The product contained 49.88 wt % of the imide product. The theoretical nitrogen content of the target compound was 13.0 to 13.7 wt %.

[0426] Example 4 - Mannich Reaction Products of Diethylamine, Formaldehyde and Benzotriazole

[0427] Main components:

[0428]

[0429] The nitrogen-containing compound of Example 4 was prepared as follows. Diethylamine (21.945 g, 301 mmol) was added to methanol (100 cm3) according to the method of Katritzky et al., J Chem Soc Perkin Trans 1987, 2673. This mixture was cooled back to 3°C and 1H benzotriazole (35.739 g, 301 mmol) was added. Aqueous formaldehyde (nominal 37 wt%, 24.324 g, 300 mmol, 1.0 eq) was added to the reactor over 10 minutes and the reaction mixture was stirred for 50 minutes and then allowed to warm to ambient temperature while stirring overnight. The methanol was removed on a rotary evaporator and 58.441 g (expected 61.33 g) of a slightly viscous yellow oil was recovered.

[0430] The obtained product was confirmed by comparison of ATR-FTIR spectrum with literature. 1 H NMR was consistent with the Katritzky reference but indicated a 1-isomer / 2-isomer ratio of 3.71. The product was found by Thermoflash elemental analyzer to contain 62.24 wt% C, 7.55 wt% H, and 27.09 wt% N. The theoretical nitrogen content of the target compound is 27.4 wt%.

[0431] A 63.5 wt % solution of the target compound in 2-ethylhexanol gave a clear, bright diesel fuel solution at up to 5 wt % active material.

[0432] Example 5 - Two-phase Mannich reaction product of diethylamine, formaldehyde and benzotriazole

[0433] Main components:

[0434]

[0435] The reaction flask was loaded with benzotriazole powder (60.0 g, 0.504 mol) and solvent 150 (102.8 g). The slurry was warmed to 30° C. and diethylamine (15.1 g) was then added. Formaldehyde solution (36.8 g of a 37 wt % formaldehyde solution) was then added over a period of 25 minutes to maintain the temperature at 40-47° C. After stirring at 40° C. for 2 hours, the reactor contained two liquid phases, which were heated to 70° C. and then transferred to a separatory funnel. The recovered aqueous phase contained 27.4 g of material. Additional water was removed by vacuum distillation at 70° C., 25 mbar, along with some organic matter, leaving a clear solution of organic material.

[0436] The product structure was confirmed by FTIR. The theoretical N content of this product was 13.7 wt%.

[0437] Example 6 - Two-phase Mannich reaction product of benzotriazole, formaldehyde and bis(2-ethylhexyl)amine

[0438] Main components:

[0439]

[0440] The nitrogen-containing compound of Example 6 was prepared as follows. A reaction flask was charged with benzotriazole powder (50.1 g, 0.421 mole) and 157 g of solvent 150. The slurry was warmed to approximately 30° C. and then bis(2-ethylhexyl)amine (101.7 g) was added over 20 minutes, followed by 34.1 g of a 37 wt % active formaldehyde solution.

[0441] The reaction mixture was heated to 80°C, transferred to a separatory funnel, and the organic layer was separated. Water was distilled from the separated organic layer to give a clear organic phase which produced an FTIR spectrum similar to that of the product of Example 5.

[0442] The theoretical nitrogen content of the target compound is 15.0 wt%.

[0443] Example 7 - Two-phase Mannich reaction product of 1,2,4-triazole, formaldehyde and di-n-butylamine

[0444] Main components:

[0445]

[0446] The nitrogen-containing compound of Example 7 was prepared as follows. 1,2,4-triazole (40.4 g, 0.585 mole) and 133.6 g of solvent 150 were loaded into a reaction flask, followed by the addition of di-n-butylamine (75.6 g). After further warming (39° C.), the addition of aqueous formaldehyde (47.4 g of a 37 wt % solution) was started.

[0447] The organic layer was separated from the reaction mixture and dried by vacuum distillation to obtain 249.6 g of a product solution. The theoretical N content of the product mixture (including the solvent) was 13.3 wt %, and the concentrate contained 13.0 wt % N, 60.8 wt % C and 8.7 wt % H by analysis.

[0448] The theoretical nitrogen content of the target compound is 26.6% by weight.

[0449] Example 8: Benzotriazole-formaldehyde-dibutylamine

[0450] Main components:

[0451]

[0452] Benzotriazole (60.1 g, 0.505 mole, 1.0 eq) and A150 solvent (131.5 g) were loaded into a 500 ml round bottom flask and heated to 30°C to form a white slurry. Dibutylamine (65.3 g, 1 eq, 0.505 mole) was added via a dropping funnel over 25 minutes. With the mixture in the flask at 31°C, formalin (37% w / w, 41.0 g, 0.505 mole, 1.0 eq) was started and allowed to stand for 15-20 minutes. A milky white liquid was formed immediately after the addition and the contents separated into two phases. The temperature of the reactor contents was then adjusted to 45-50°C and maintained at this temperature for 5 hours. The reaction mixture was allowed to cool overnight. To separate the reaction mixture, it was heated to 70°C. The separation was clear and the lower, now turbid, aqueous layer was drained. 30.9 g was collected and the theoretical water in the reaction was 34.9 g. The organic phase was heated to 75°C and vacuum was applied to -20 mbar. 254.9 g of a clear bright yellow liquid were isolated (as a -50% active solution).

[0453] The theoretical nitrogen content of the target compound is 21.5% by weight.

[0454] Example 9: Benzotriazole-formaldehyde-Armeen 2C (dicocoyl alkylamine)

[0455] Main components:

[0456]

[0457] Benzotriazole (26.0 g, 0.218 mole, 1.0 eq) and A150 solvent (116.0 g) were charged to a 500 ml round bottom flask and heated to 90°C. Armeen 2C (87.4 g, 0.218 mole, 1 eq [equivalent to 401 g / mol]) (a mixture of dicocoalkylamines, wherein cocoalkyl = C6-18 alkyl) was charged to the flask. Formalin (37% w / w, 0.218 mole, 1.0 eq) was then added over 5 minutes and the reaction mixture was then stirred at 90°C for 2.5 hours. The temperature in the reaction flask was raised to 119°C over a period of 3 hours and water was removed via a Dean and Stark trap. When no further aqueous phase was collected and the product was clear and bright, the temperature was cooled to ambient temperature. 222.5 g of a clear, bright amber liquid was collected (as a 50% active solution).

[0458] Example 10: 1,2,4-Triazole-formaldehyde-bis(2-ethylhexyl)amine

[0459] Main components:

[0460]

[0461] Formalin (159.6 g of 26.6% active formaldehyde, 1.9447 mol, 0.995 eqs) and 1,2,4-triazole (156.0 g, 1.9545 mols, 1.0 equiv) were loaded and heated to 60°C. Bis-(2-ethylhexyl)amine (462.5 g, 1.9154 mols, 0.98 equivs) was added to the water mixture at 60°C over 2.5 hours and the batch was stirred for 1 hour to complete the reaction. Water and reaction water from the formalin solution were removed by vacuum distillation at 60-100°C (100-200 mbar). After the water was removed, residual volatiles and traces of water were removed by stripping under increased vacuum and the product (615.4 g) was discharged as a light yellow liquid through a filter.

[0462] The theoretical nitrogen content of the target compound is 17.4% by weight.

[0463] Engine testing

[0464] Engine testing was conducted as described below to evaluate the performance of the nitrogen-containing additives of the present invention in reducing deposits in the exhaust gas recirculation system of a diesel engine.

[0465] Engine Details

[0466] A 2.0-liter HSDI engine that complies with the Euro 6 standard is connected to a test automation system and a test bench equipped with an engine dynamometer. The engine is controlled by an ECU supplied by the engine manufacturer. Before the first test, the engine has been used for more than 1100 hours. The engine oil is changed before the first test.

[0467] Modify / Experiment with settings

[0468] 1. There is no SCR catalyst or related components in the exhaust system.

[0469] 2. The high pressure EGR cooler was artificially controlled to 40°C during the test.

[0470] The base fuel was RF-06-03 diesel fuel (Haltermann Carless, UK) with the following specifications:

[0471]

[0472] Test additives, treatment rate:

[0473] The nitrogen-containing compound of the example was metered into the above base diesel fuel at 100 mg / kg. The nitrogen-containing compound A of Example 1 was metered into the base fuel to provide Test Fuel A.

[0474] The amount of soot deposited in the EGR cooler was determined by weighing the assembly before and after each test.

[0475] Clean the EGR cooler thoroughly using tap water sprayed under high pressure through the cooler matrix. This cleaning process is carried out until deposits are no longer visible to the naked eye in the cooler matrix.

[0476] The EGR cooler is then placed in an oven preheated to 185°C and fixed to a scale. Once the scale has stabilized, the weight measurement is taken as an average value taken over 15 minutes. This weighing process is repeated at the end of the test. The difference between the weights measured before and after the test represents the mass change caused by soot deposition.

[0477] Testing Procedure

[0478] -[D] Clean and weigh the EGR

[0479] -[D]DPF+Slave EGR installation

[0480] -Engine start + warm up

[0481] - Passive DPF regeneration is performed by varying engine speed and load until regeneration is complete. The pressure differential across it is used to monitor the progress of regeneration.

[0482] - Engine stop

[0483] -Change to test fuel

[0484] -[C]DPF+Slave EGR removal

[0485] -[C]DPF Start of Test (SOT) weighing

[0486] [C]DPF+[C]EGR installation

[0487] -Engine start + warm up

[0488] -8 hours steady state test cycle

[0489] -1200RPM

[0490] -60Nm

[0491] - Engine stop

[0492] [D]DPF removal and end-of-test (EOT) weighing

[0493] [D] EGR removal and EGR test end weighing

[0494] [C] indicates a clean component

[0495] [D] indicates a fouled component

[0496] result

[0497]

[0498] These results demonstrate that the use of the nitrogen-containing compounds described herein as additives in diesel fuel compositions can provide a significant reduction in deposits in the exhaust gas recirculation system of a diesel engine combusting the fuel.

Claims

1. Use of one or more nitrogen-containing compounds as an additive in a diesel fuel composition to reduce the effect of deposits in the exhaust gas recirculation system of a diesel engine when the diesel fuel composition is combusted, wherein the nitrogen-containing compound comprises at least 4% by mass of nitrogen atoms.

2. A method for reducing the effects of deposits in an exhaust gas recirculation system of a diesel engine, the method comprising burning in the engine a diesel fuel composition comprising as an additive one or more nitrogen-containing compounds, wherein the nitrogen-containing compounds comprise at least 4 mass % of nitrogen atoms.

3. Use or method according to claim 1 or claim 2, which reduces the formation of deposits in the exhaust gas recirculation system of the diesel engine.

4. The use or method according to any one of the preceding claims, wherein the exhaust gas recirculation system is a high pressure exhaust gas recirculation system, wherein the high pressure EGR system is a stand-alone high pressure EGR system, or is part of a hybrid or dedicated EGR system.

5. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound is the reaction product of a) a hydrocarbyl-substituted reagent and b) a nitrogen-containing reagent.

6. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound has formula (I): A-L-R 1 (I) in: A is a nitrogen-containing group; L is a bond or a linker; and R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000.

7. The use or method of claim 6, wherein the nitrogen-containing group A is a nitrogen-containing heterocycle and is selected from optionally substituted piperazine, pyridine, pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline, quinazoline, a five-membered heterocyclic ring such as pyrazole or imidazole, or a benzo-fused five-membered heterocyclic ring such as benzimidazole.

8. The use or method according to claim 6, wherein the A group is an acyclic nitrogen-containing group having formula (II): (II) Wherein n is 1 to 10.

9. The use or method according to any one of claims 6 to 8, wherein L is a bond, an amide, succinimide, succinic acid or an amide of succinic acid.

10. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound is the reaction product of: a) a hydrocarbyl-substituted carboxylic acylating agent; and b) Nitrogen-containing reagents.

11. The use or method according to claim 10, wherein component a) has formula (aI): Where R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight (Mn) of up to 1,000.

12. The use or method according to claim 10 or claim 11, wherein component b): is selected from optionally substituted benzotriazole, amino-benzotriazole, indazole, amino-indazole, triazole, amino-triazole, tetrazole or amino-tetrazole; or Having formula (bI): Wherein n is 1 to 10.

13. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound has the formula (III): in: A is a nitrogen-containing group; R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight of up to 1,000; and R 2 It is OH, NH2, OR 4 、NHR 4 or NR 4 R 5 , where R 4 and R 5 is independently selected from optionally substituted C1-6 alkyl or alkenyl, or is a bond to A.

14. The use or method of claim 13, wherein the nitrogen-containing compound has formula (IV), (IVb) or (IVc), or a mixture thereof: Where R 1 and R 2 As defined in claim 12.

15. The use or method of claim 13, wherein the nitrogen-containing compound has formula (V): wherein n is 1 to 3, or a mixture thereof; and Where R 1 As defined in claim 12.

16. The use or method according to any one of claims 1 to 7, wherein the nitrogen-containing compound is the reaction product of: a) amines or polyamines containing hydrocarbon groups; b) nitrogen-containing reagents; and c) Aldehydes.

17. The use or method according to claim 16, wherein: a) is of the formula NHR 7 R 8 Alkylamine, where R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl; b) is a nitrogen-containing reagent selected from optionally substituted triazole, tetrazole, indole, indazole or benzotriazole, and c) is formaldehyde or a source of formaldehyde.

18. The use or method according to any one of claims 1 to 7, 16 or 17, wherein the nitrogen-containing compound has formula (VI): in: R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight of up to 1,000; W, X, Y and Z are each independently selected from CH, C, N, NH, S and SH; and The compound optionally comprises a cycloalkyl or aryl ring connecting Y and Z.

19. The use or method of claim 18, wherein the nitrogen-containing compound has formula (IX): in: R 1 is an optionally substituted alkyl, alkenyl or aminoalkyl group having a molecular weight of up to 1,000; W and X are each independently selected from C and N; and Each R 6 Independently selected from H, C1-6 alkyl or C1-6 alkenyl.

20. The use or method according to claim 19, wherein R 1 It is CH2NR 7 R 8 , and R 7 and R 8 Each is independently selected from H, optionally substituted C1-20 alkyl or optionally substituted C1-20 alkenyl.

21. The use or method according to any one of the preceding claims, wherein the nitrogen-containing compound comprises less than 5 NH bonds.

22. The use or method according to any one of the preceding claims, wherein the diesel fuel composition comprises from 50 to 2000 ppm of the one or more nitrogen containing compounds.

23. The use or method according to any one of the preceding claims, wherein the diesel fuel composition comprises from 50 to 350 ppm of the one or more nitrogen containing compounds.

24. Use or method according to any preceding claim for reducing deposits in an exhaust gas recirculation system of a diesel engine having a pressure in excess of 1350 bar.

25. Use or method according to any preceding claim, which reduces deposit formation on a cooler of an EGR system.

26. Use or method according to any preceding claim which reduces deposit formation in an EGR system by at least 5%.

27. The use or method according to any one of the preceding claims, wherein the diesel fuel composition comprises one or more nitrogen-containing detergents.

28. The use or method of claim 27, wherein the one or more nitrogen-containing detergents are selected from: (i) quaternary ammonium salt additives; (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and (iii) The reaction product of a carboxylic acid derived acylating agent and an amine.

29. A fuel additive composition comprising one or more nitrogen-containing compounds and a detergent additive, wherein the nitrogen-containing compounds contain at least 4 mass % nitrogen atoms.

30. A diesel fuel composition comprising one or more nitrogen-containing compounds and a detergent additive, wherein the nitrogen-containing compounds comprise at least 4 mass % nitrogen atoms.

31. A diesel fuel composition according to claim 30 comprising one or more additional additives selected from antioxidants, dispersants, detergents, metal deactivating compounds, wax anti-settling agents, cold flow improvers, cetane improvers, dehazers, stabilizers, demulsifiers, defoamers, corrosion inhibitors, lubricity improvers, dyes, markers, combustion improvers, metal deactivators, odor masking agents, drag reducers and conductivity improvers.

32. A fuel additive composition according to claim 29 or a diesel fuel composition according to claim 30 or claim 31, wherein the detergent additive is: The reaction product of tetraethylenepentamine (TEPA) and PIBSA having a PIB number average molecular weight (Mn) of 300 to 2800; or A quaternary ammonium salt formed by reacting the reaction product of dimethylaminopropylamine and a polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight (Mn) of 700 to 1300 with methyl salicylate or dimethyl oxalate; or a mixture thereof.

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