BR112020026651A2 - COMPOSITIONS, USES AND METHODS TO IMPROVE LOW TEMPERATURE PROPERTIES OF A MEDIUM DISTILLED FUEL - Google Patents

Abstract

compositions, uses and methods to improve the low temperature properties of a medium distilled fuel. a method for improving the low temperature properties of a medium distillate fuel composition comprising: (a) a nitrogen-containing dispersant; and (b) one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof; wherein the method comprises adding to the fuel an additive (c) which is a copolymer comprising units of formula (a); and units of formula (b) where r is an alkyl group and each of r1 and r2 is an alkyl group.

Description

“COMPOSITIONS, USES AND METHODS TO IMPROVE THE LOW TEMPERATURE PROPERTIES OF A MEDIUM DISTILLED FUEL ”

[001] The present invention relates to additives that affect the low temperature properties of medium distillate fuel compositions. In particular, the invention relates to additives that neutralize negative interactions between other additive compounds in the fuel at low temperatures.

[002] The low temperature properties of fuels have been extensively studied, and in many countries it is common to have to add fuel additives to avoid problems when the fuel is stored at low temperatures.

[003] Standardized tests were designed to measure various low temperature properties of medium distillate fuels, including the temperature at which the fuel turbid (the fog point - CP), the lowest temperature at which a fuel can flow (the fluidity - PP) and the cold filter clogging point - CFPP.

[004] The mist point of a fuel is the temperature at which a mist of wax crystals first appears in a liquid when it is cooled under prescribed conditions, for example, as measured by the test method as defined in ASTM D 2500.

[005] At temperatures below the fog point, but above the pour point, the wax crystals can reach a size and shape capable of clogging fuel lines, screens and filters even if the fuel flows physically. These problems are well recognized in the art and have several recognized test methods such as the CFPP value (cold filter plugging point, determined according to DIN EN 116).

[006] Tests like these were introduced to give an indication of low temperature operability, as the fog point test was considered to be very pessimistic.

[007] Fuel additives in the form of cold flow improvers (CFIs also known as medium distillate flow improvers or MDFIs) and wax antideposition additives (WASAs) were developed to improve precipitation problems in low fuel temperatures, and these are routinely added to medium distillate fuels.

[008] Some of these additives can help keep so-called “waxes” in solution in mineral fuel; others can alter their morphology or crystal size, so that filterability and fluidity are maintained despite precipitation. Other additives can be used to prevent precipitated waxes from settling during storage.

[009] It has generally been found that these additives are very successful, insofar as such fuels, properly added, can be used even under severe low temperature conditions. In many fuels, the CFPP value can be reduced by 10 to 20 ºC, compared to the corresponding fuels without additives.

[010] It is therefore common practice to include additives that improve low temperature properties, such as WASAs and / or MDFIs for medium distillate fuels. Additive packages that comprise a combination of WASA and MDFI are also commonly used and known as WAFIs.

[011] The short sediment test (SST) measures the propensity of the wax content of a fuel oil to settle and can be used to determine the effectiveness of wax antideposition additives or combinations of additives. In the test, the Mist Point (CP) of a base fuel is measured. The additive (s) under study is (are) added to the base fuel and the sample is stored at a particular temperature, typically 7 ° C below the measured CP, for 16 hours. It is possible to observe the amount of wax that is believed to have set. The lower 20% of the fuel is then taken and the CP of that sample is measured and compared with that of the base fuel or that of the upper 80%, depending on the particular test conditions. The difference between the CP of the base fuel or the upper 80% and the CP of the lower 20% of the additive fuel (CP) is a measure of the degree of wax deposition. A low CP value, preferably around zero, indicates good dispersion of wax. Low sediment levels can be used as an additional measure of good wax dispersion.

[012] It is also routine practice to include nitrogen-containing dispersing compounds / detergents in medium distillate fuels. They are necessary to ensure the cleanliness of the engine and to improve engine performance. Typical classes of nitrogen-containing detergents will be known to those skilled in the art and include, for example, succinimides, Mannich reaction products and quaternary ammonium salts.

[013] However, in certain medium distillate fuels, an antagonistic interaction can occur between nitrogen-containing detergents and wax antideposition additives and / or medium distillate flow enhancers that affect the fuel's low temperature properties.

[014] Antagonism results in poorer dispersion of waxes in storage, leading to unexpected poor performance when fuels are stored at low temperatures. This effect can be seen in the Short Sediment Test (SST).

[015] The antagonism between detergents and WASA / MDFIs is a phenomenon that is widely known in the art. However, it does not occur in all fuels and it is difficult to predict whether or not it is likely to occur in a particular fuel.

[016] Various solutions to this problem have been proposed and several additives that can be used to improve negative interaction have been described, for example, refer to EP 1932899, US 8021444, US 8153567, US 8628590, US 8628591, US 8734542, US 20100154294, US 20100180492 and US 20100236139.

[017] However, due to the significant variability of fuels, the solutions that have been proposed do not always solve the problem and, therefore, there is an ongoing need for alternative solutions to this problem.

[018] In accordance with a first aspect of the present invention, a method of improving the low temperature properties of a medium distillate fuel composition is provided which comprises: a nitrogen-containing dispersant; and one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from: (x) wax antideposition additives; (y) medium distillate flow improvers; and mixtures thereof; wherein the method comprises adding to the fuel an additive (c) which is a copolymer comprising units of formula (A): (A) and units of formula (B): (B) where R is an alkyl group and each of R1 and R2 is an alkyl group.

[019] In accordance with a second aspect of the present invention, use is provided of (c) a copolymer comprising units of formula (A): (A) and units of formula (B): (B) where R is an alkyl group and each of R1 and R2 is an alkyl group; to improve the low temperature properties of a medium distillate fuel composition comprising: a nitrogen-containing dispersant; and one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from: (x) wax antideposition additives; (y) medium distillate flow improvers; and mixtures thereof.

[020] According to a third aspect of the present invention, an additive composition is provided to improve the low temperature properties of a medium distillate fuel composition, wherein the additive composition comprises:

[021] one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from: (x) wax antideposition additives; (y) medium distillate flow improvers; and mixtures thereof; and a copolymer comprising units of formula (A): (A) and units of formula (B): (B) in which R is an alkyl group and each of R1 and R2 is an alkyl group.

[022] In accordance with a fourth aspect of the present invention, a medium distillate fuel composition is provided which comprises: a nitrogen-containing dispersant; one or more low temperature property enhancers which are not vinyl ester fumarate copolymers and which are selected from: (x) wax antideposition additives; (y) medium distillate flow improvers; and mixtures thereof; and a copolymer comprising units of formula (A):

(A) and units of formula (B): (B) where R is an alkyl group and each of R1 and R2 is an alkyl group.

[023] The preferred features of the first, second, third and fourth aspects of the invention will now be described.

[024] The present invention relates to the enhancement of the low temperature properties of a medium distillate fuel composition by the addition of an additive (c) which is a copolymer comprising units of formula (A): (A)

[025] and units of formula (B):

(B) where each of R1 and R2 is an alkyl group.

[026] Additive (c) can be prepared by copolymerizing vinyl ester monomers and fumaric acid monomers and then by esterifying acid residues.

[027] Preferably, additive (c) is prepared by copolymerizing vinyl ester monomers and dialkyl fumarate monomers.

[028] The additive (c) is preferably a copolymer prepared by the reaction of vinyl ester monomers of formula (C): (C) and dialkyl fumarate monomers of formula (D): (D)

[029] Each monomer of formula (C) used to prepare the copolymer additive (c) can be the same or the copolymer can be prepared from a mixture of two or more different monomers of formula (C).

[030] R is an alkyl group, preferably an unsubstituted alkyl group.

[031] Preferably, R is an alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms.

[032] Preferably, R is an unsubstituted alkyl group with 1 to 4 carbon atoms.

[033] More preferably, R is methyl and the monomer of formula (C) is vinyl acetate.

[034] Each monomer of formula (D) used to prepare the copolymer additive (c) can be the same or the copolymer can be prepared from a mixture of two or more different monomers of formula (D).

[035] Preferably, all monomers of formula (D) used to prepare additive (c) are the same.

[036] Each of R1 and R2 can be the same or different. Preferably. R1 is equal to R2.

[037] Each of R1 and R2 is an alkyl group. Preferably, each is an unsubstituted alkyl group. R1 and R2 can be single or branched. Preferably, each of R1 and R2 is a single-chain alkyl group.

[038] Preferably, each of R1 and R2 is an alkyl group with less than 18 carbon atoms.

[039] Preferably, each of R1 and R2 is an alkyl group with 6 to 17 carbon atoms, preferably 6 to 16 carbon atoms, more preferably 8 to 16 carbon atoms, preferably 10 to 16 carbon atoms , more preferably 12 to 16 carbon atoms, suitably 12 to 14 carbon atoms and more preferably 14 carbon atoms. More preferably, R1 is C14H29 and R2 is C14H29.

[040] The additive (c) is a copolymer comprising units of formula (A) and units of formula (B). In some embodiments, the additive (c) may further comprise additional units that are not of formula (A) or formula (B). In such embodiments, the copolymer is suitably prepared from vinyl ester monomers, fumaric acid-derived monomers (preferably dialkyl fumarate) and one or more additional monomer units. In preferred embodiments, the one or more additional monomer units comprise less than 20 mol% of all the monomer units used to prepare the additive (c), preferably less than 10 mol%, more preferably less than 5 mol% mol, more preferably less than 1 mol%.

[041] In preferential terms, the additive (c) consists essentially of units of formula (A) and units of formula (B). This means that units of formula (A) and units of formula (B) together provide at least 80 mol% of all monomer-derived units present in the copolymer, preferably at least 90 mol%, more preferably at least 95% in mol, more preferably at least 99% by mol, for example, at least 99.5% by mol or at least 99.9% by mol.

[042] Suitably, the additive (c) comprises from 10 to 90 mol% of units of formula (A) and from 90 to 10 mol% of units of formula (B); preferably from 25 to 75 mol% of units of formula (A) and from 25 to 75 mol% of units of formula (B); more preferably from 40 to 60 mol% of units of formula (A) and from 60 to 40 mol% of units of formula (B).

[043] Preferably, additive (c) is a random copolymer.

[044] Suitably, the copolymer additive (c) has a numerical average molecular weight of 1,000 to 100,000, preferably 2,000 to 50,000, more preferably 5,000 to 30,000, for example, 8,000 to 25,000.

[045] In some preferred embodiments, copolymer additives (c) have a numerical average molecular weight of 20,000 to 25,000.

[046] In some especially preferred embodiments, the copolymer additive (c) has a numerical average molecular weight of 8,000 to 12,000.

[047] In especially preferred embodiments, additive (c) is a copolymer comprising units of formula (A): (A) and units of formula (B): (B) where R is an alkyl group, each of R1 and R2 is an alkyl group with less than 18 carbon atoms, preferably 12 to 16 carbon atoms, and where the copolymer has a numerical average molecular weight of 8,000 to

25,000. More preferably, the copolymer comprises from 40 to 60 mol% of units of formula (A) and from 60 to 40 mol% of units of formula (B).

[048] Additive (c) is used to enhance the low temperature properties of a medium distillate fuel composition that comprises: a nitrogen-containing dispersant; and one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof.

[049] Any detergent containing suitable nitrogen can be used as component (a).

[050] Nitrogen-containing detergents suitable for use in this document include: a quaternary ammonium salt additive; the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; the reaction product of an acylating agent derived from carboxylic acid and an amine; the reaction product of an acylating agent derived from carboxylic acid and hydrazine; a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine; the reaction product of a dicarboxylic acid substituted by hydrocarbyl or anhydride and an amine or salt compound whose product comprises at least one amino triazole group; and an amine substituted by alkylene.

[051] Preferably, component (a) comprises one or more of: a quaternary ammonium salt additive; the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and the reaction product of an acylating agent derived from carboxylic acid and an amine.

[052] In some embodiments, component (a) comprises (i) a quaternary ammonium salt additive.

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

[054] The nitrogen-containing species can be selected from:

the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine, secondary or alcohol group; a Mannich reaction product comprising a tertiary amine group; and an alkylene substituted amine with at least one tertiary amine group.

[055] Examples of quaternary ammonium salt and methods for preparing them are described in the following patents, which are incorporated herein by reference, US 2008/0307698, US 2008/0052985, US 2008/0113890 and US 2013 / 031827.

[056] The preparation of some suitable quaternary ammonium salt additives in which the nitrogen-containing species includes component (p) is described in WO 2006/135881 and WO 2011/095819.

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

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

[059] In preferred embodiments, the nitrogen-containing species used to prepare the quaternary ammonium salt additive (i) is of type (p), the reaction product of an acylating agent substituted by hydrocarbyl and a compound with an atom of oxygen or nitrogen capable of condensing with said acylating agent and also with a tertiary amino group.

[060] The hydrocarbyl-substituted acylating agent is preferably a mono- or polycarboxylic acid (or reactive equivalent thereof), for example, a substituted succinic, phthalic or propionic acid.

[061] Most preferably, the acylating agent is a hydrocarbyl-substituted succinic acid or anhydride.

[062] The hydrocarbyl substituent on these acylating agents preferably comprises at least 8, more preferably at least 12, for example, 30 or 50 carbon atoms. It can comprise up to about 200 carbon atoms. Preferably, the hydrocarbyl substituent of the acylating agent has a numerical average molecular weight (Mn) between 170 to 2,800, for example, from 250 to 1,500, preferably from 500 to 1,500 and more preferably 500 to 1,100. A 700 to 1,300 Mn is especially preferred, for example, from 700 to 1,000.

[063] In some preferred embodiments, the hydrocarbyl-based substituents are poly (isobutenes) known in the art. Thus, in especially preferred embodiments, the hydrocarbyl-substituted acylating agent is a polyisobutenyl-substituted succinic anhydride.

[064] The preparation of succinic anhydrides substituted by polyisobutenyl (PIBSA) is documented in the art.

[065] Examples of compounds containing nitrogen or oxygen capable of condensing with the acylating agent and also with a tertiary amino group may include, but are not limited to: N, N-dimethylaminopropylamine, N, N-diethylaminopropylamine, N, N- dimethylamino ethylamine, 1- (3-aminopropyl) imidazole, 4- (3-aminopropyl) morpholine, 1- (2-aminoethyl) piperidine, 3,3-diamino-N-methylldipropylamine, and 3'3-aminobis (N, N -dimethylpropylamine), triethanolamine, trimethanolamine, N, N-dimethylaminopropanol, N, N-dimethylaminoethanol, N, N-diethylaminopropanol, N, N-diethylaminoethanol, N, N-diethylaminobutanol, N, N, N-tris (hydroxyethyl) amine, N, N, N-tris (hydroxymethyl) amine, N, N, N-tris (aminoethyl) amine, N, N-dibutylaminopropylamine and N, N, N'-trimethyl-N'-hydroxyethyl-bisaminoethyleter; N, N-bis (3-dimethylaminopropyl) -N-isopropanolamine; N- (3-dimethylaminopropyl) -N, N-diisopropanolamine; N '- (3- (dimethylamino) propyl) - N, N-dimethyl 1,3-propanediamine; 2- (2-dimethylaminoethoxy) ethanol, and N, N, N'-trimethylaminoethylethanolamine.

[066] Most preferably, the alcohol or amine compound that reacts with the acylating agent and has a tertiary amino group is dimethylaminopropylamine or dimethylaminopropanol.

[067] The quaternary ammonium salt additive (i) is formed by the reaction of a nitrogen-containing species with a tertiary amine group with a quaternizing agent.

[068] The quaternizing agent can be appropriately selected from esters and non-esters.

[069] The quaternization agent is suitably selected from the group consisting of dialkyl sulfates; a carboxylic acid ester; alkyl halides; benzyl halides; carbonates replaced by hydrocarbyl; and hydrocarbyl epoxides in combination with an acid or mixtures thereof.

[070] Examples of hydrocarbyl epoxides may include styrene oxide, ethylene oxide, propylene oxide, butylene oxide, stylbene oxide and C2-50 epoxide.

[071] Suitable ester quaternizing agents include esters of a carboxylic acid selected from one or more oxalic acid, phthalic acid, salicylic acid, maleic acid, malonic acid, citric acid, nitrobenzoic acid, aminobenzoic acid and 2, 4,6-trihydroxybenzoic.

[072] 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.

[073] An especially preferred quaternary ammonium salt for use in this document is formed by the reaction of methyl salicylate or dimethyl oxalate with the reaction product of a succinic anhydride replaced by polyisobutylene with a numerical average molecular weight of GDP of 700 to

1,300 and dimethylaminopropylamine.

[074] Other suitable quaternary ammonium salts include quaternized terpolymers, for example, as described in US 2011/0258917; quaternized copolymers, for example, as described in US 2011/0315107; and the acid-free quaternized nitrogen compounds disclosed in US 2012/0010112.

[075] Additional suitable quaternary ammonium compounds for use in the present invention include the quaternary ammonium compounds described in applicant's copendent applications WO 2011095819, WO 2013/017889, WO 2015/011506, WO 2015/011507, WO 2016/016641 and PCT / GB2016 / 052312.

[076] In some embodiments, component (a) comprises (ii) the 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.

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

[078] Amines suitable for use in the preparation of Mannich's additive include monoamines and polyamines. A suitable monoamine is butylamine.

[079] The amine used to prepare the Mannich additive is preferably a polyamine. This can be selected from any compound including two or more amino groups. Preferably, the polyamine is a polyalkylene polyamine, preferably a polyethylene polyamine, especially a polyethylene polyamine with 1 to 10 ethylene groups and 2 to 11 amine groups.

[080] Commercially available polyamine sources typically contain mixtures of isomers and / or oligomers, and products prepared from such commercially available mixtures are within the scope of the present invention.

[081] Suitably, the polyamine can be selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylene-hexamine, hexaethylene-heptamine, heptaethylene-octamine, propane-1,2-diamine, 2 (2-amino-ethylamine) ) ethanol and N ', N'-bis (2-aminoethyl) ethylenediamine (N (CH2CH2NH2) 3).

[082] Most preferably, the polyamine comprises tetraethylenepentamine or ethylenediamine.

[083] The optionally substituted phenol component used to prepare the Mannich additive can be substituted by 0 to 4 groups on the aromatic ring (in addition to the OH phenol). For example, it can be a cresol substituted by hydrocarbyl. Most preferably, the phenol component is a monosubstituted phenol. Preferably, it is a hydrocarbyl-substituted phenol. Preferred hydrocarbyl substituents are alkyl substituents with 4 to 28 carbon atoms, especially 10 to 14, for example, 12 carbon atoms. Other preferred hydrocarbyl substituents are polyalkenyl substituents. Such polyisobutenyl substituents with a numerical average molecular weight of 400 to 2,500, for example, from 500 to 1,500.

[084] Suitable Mannich reaction products useful herein as additives are described in the applicant's patents and applications of the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and an amine group primary, secondary amine or alcohol; WO 2009/040582, WO 2009/040583, WO 2009/040584, WO 2009/040585, WO 2010/097624, WO 2013/017884, WO 2013/017886 and WO 2013/017887.

[085] The preferred Mannich reaction product additives for use in this document are the reaction product of a phenol substituted by hydrocarbyl, formaldehyde and a polyamine, preferably a polyethylene polyamine.

[086] Preferably, the Mannich reaction product additive is formed by the reaction of a phenol substituted by an alkyl group with 6 to 30 carbon atoms or a polyisobutenyl group with a numerical average molecular weight of 500 to 2,000 with formaldehyde and a polyamine, preferably a polyethylene polyamine.

[087] Mannich reaction products especially preferred for use herein as a detergent containing nitrogen (a) are the reaction product of dodecylphenol, formaldehyde and ethylenediamine or tetraethyl pentamine.

[088] In some embodiments, component (a) comprises (iii) the reaction product of an acylating agent derived from carboxylic acid and an amine.

[089] These can also be referred to in this document, in general, as compounds containing acylated nitrogen.

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

[091] The preferred hydrocarbyl-substituted acylating agents are polyisobutenyl succinic anhydrides. These compounds are commonly referred to as "PIBSAs" and are known to those skilled in the art.

[092] Conventional polyisobutenes and so-called "highly reactive" polyisobutenes are suitable for use in the invention. Highly reactive polyisobutenes are preferred.

[093] Especially preferred PIBSAs are those with a molecular weight (Mn) of GDP of 300 to 2,800, preferably from 450 to 2,300, more preferably from 500 to 1,300.

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

[095] A preferred acylated nitrogen-containing compound for use in this document is prepared by reacting an acylating agent derived from succinic acid substituted by poly (isobutene) (eg, anhydride, acid, ester, etc.), in which the poly (isobutene) substituent has a numerical average molecular weight (Mn) between 170 to 2,800 with a mixture of ethylene polyamines with 2 to about 9 amino nitrogen atoms, preferably about 2 to about 8 nitrogen atoms, for example ethylene polyamine and about 1 to about 8 ethylene groups. These acylated nitrogen compounds are suitably formed by reacting an acylating agent: amino compound molar ratio of 10: 1 to 1:10, preferably from 5: 1 to 1: 5, more preferably from 2: 1 to 1: 2 and more preferably from 2: 1 to 1: 1. In especially preferred embodiments, the acylated nitrogen compounds are formed by the reaction between the acylating agent and the amino compound in a molar ratio of 1.8: 1 to 1: 1.2, preferably 1.6: 1 to 1: 1 , 2, more preferably from 1.4: 1 to 1: 1.1 and more preferably from 1.2: 1 to 1: 1. Acylated amino compounds of this type and their preparation are well known to those skilled in the art and are described, for example, in EP 0565285 and US 5925151.

[096] In some preferred embodiments, the composition comprises a detergent of the type formed by the reaction of an acylating agent derived from succinic acid substituted by poly (isobutene) and a polyethylene polyamine. Suitable compounds are, for example, described in WO 2009/040583.

[097] Especially preferred additives of this type are the reaction product of a polyisobutenyl-substituted succinic acid / anhydride with a molecular weight (Mn) of GDP of 500 to 1,300 and a polyethylene polyamine with 1 to 9 amino groups and 1 to 8 ethylene groups.

[098] In some embodiments, component (a) comprises (iv) the reaction product of an acylating agent derived from carboxylic acid and hydrazine.

[099] Suitably, the additive comprises the reaction product between an acid or succinic anhydride substituted by hydrocarbyl and hydrazine.

[100] Preferably, the hydrocarbyl group of the hydrocarbyl-substituted succinic acid or succinic anhydride comprises a C8-C36 group, preferably a C8-C18 group. Alternatively, the hydrocarbyl group may be a polyisobutylene group with a numerical average molecular weight between 200 and 2,500, preferably between 800 and 1,200.

[101] Hydrazine has the formula NH2-NH2. Hydrazine can be hydrated or non-hydrated. Hydrazine monohydrate is preferred.

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

[103] In some embodiments, component (a) 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.

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

[105] In a preferred embodiment, the carboxylic acid comprises talloyl fatty acid (TOFA).

[106] The additional preferred features of additives of this type are described in EP 1900795.

[107] In some embodiments, component (a) comprises (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine or salt compound whose product comprises at least one amino triazole group.

[108] The additional preferred features of additive compounds of this type are as defined in US 2009/0282731.

[109] In some embodiments, component (a) comprises (vii) an alkylene-substituted amine.

[110] Polyalkene-substituted amines can be derived from an olefin polymer and an amine, for example, ammonia, monoamines, polyamines or mixtures thereof. They can be prepared by a variety of methods such as those described and referred to in US 2008/0113890.

[111] Suitably, the polyalkene substituent of the polyalkene-substituted amine is derived from a polyisobutylene.

[112] The numerical average molecular weight of amines substituted by polyalkene can be in the range of 500 to 5,000, or from 500 to 3,000, for example, from 1,000 to 1,500.

[113] Preferably, component (a) comprises one or more of:

[114] a quaternary ammonium salt additive formed by the reaction of a quaternizing agent and the reaction product of a hydrocarbyl-substituted acylating agent and a compound comprising at least one tertiary amine group and a primary amine group, secondary amine or alcohol;

[115] the product of a Mannich reaction between a phenol substituted by hydrocarbyl, formaldehyde and a polyamine; and

[116] the reaction product of an acylating agent derived from succinic acid replaced by hydrocarbyl and an amine.

[117] More preferably, component (a) is selected from one or more of: a quaternary ammonium salt additive formed by the quaternizing agent reaction and the reaction product of a succinic anhydride replaced by polyisobutenyl and an amine or alcohol which still includes a tertiary amino group, preferably in which the quaternizing agent is selected from the group consisting of dialkyl sulfates; an ester of a carboxylic acid; alkyl halides; benzyl halides; carbonates replaced by hydrocarbyl; and hydrocarbyl epoxides in combination with an acid or mixtures thereof; the product of a Mannich reaction between a phenol substituted by an alkyl group with 6 to 30 carbon atoms or a polyisobutenyl group with a numerical average molecular weight of 500 to 2,000; by formaldehyde; and a polyamine selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylene-hexamine, hexaethylene-heptamine, heptaethylene-octamine, propane-1,2-diamine, 2 (2-amino-ethylamino) ethanol, and N ', N'- bis (2-aminoethyl) ethylenediamine (N (CH2CH2NH2) 3); and the reaction product of an acylating agent derived from succinic acid replaced by polyisobutenyl and a polyamine.

[118] Most preferably, component (a) is selected from one or more of: a quaternary ammonium salt additive formed by the reaction of methyl salicylate or dimethyl oxalate with the reaction product of a succinic anhydride replaced by poly -isobutylene with a numerical average molecular weight of GDP of 700 to 1,300 and dimethylaminopropylamine; the Mannich reaction product of dodecylphenol, formaldehyde and ethylene diamine or tetraethyl pentamine; and the reaction product of a succinic acid / anhydride substituted by polyisobutenyl with a molecular weight (Mn) of GDP of 500 to 1,300 and a polyethylene polyamine with 1 to 9 amino groups and 1 to 8 ethylene groups.

[119] Component (b) comprises one or more low temperature property enhancers which are not vinyl ester fumarate copolymers and which are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof.

[120] Preferably, component (b) comprises at least one wax antideposition additive (x).

[121] Preferably, component (b) comprises at least one medium distillate flow enhancer (y).

[122] More preferably, component (b) comprises at least one wax antideposition additive (x) and at least one medium distillate flow enhancer (y).

[123] The preferred wax antideposition additives (x) are the reaction product of (I) a compound containing the –NR3R4 segment, where R3 represents a group containing from 4 to 44 carbon atoms and R4 represents a hydrogen atom or an R3 group, and (II) a carboxylic acid with 1 to 4 carboxylic acid groups or a reactive equivalent thereof.

[124] Preferably, R3 is a hydrocarbyl group or a polyethoxylate or polypropoxylate group.

[125] Preferably, the group R3 is a hydrocarbyl group. Preferably, R3 is a hydrocarbon group, preferably a single-chain hydrocarbon group.

[126] Preferably, the group R3 comprises 6 to 36 carbon atoms, preferably 8 to 32, preferably 10 to 24, preferably 12 to 22, more preferably 14 to 20.

[127] It will be appreciated by those skilled in the art that commercial sources of alkylamines and dialkylamines may contain mixtures of homologues. Additives derived from these compounds are within the scope of the present invention.

[128] R4 can be a group according to the definition of R3 or hydrogen.

[129] R4 preferably complies with the same definitions given to R3. R3 and R4 do not have to be the same. Preferably, however, R3 and R4 are the same.

[130] Species (II) is a carboxylic acid or a reactive equivalent thereof.

[131] The reactive equivalents of a carboxylic acid include acid anhydrides, spirobislactones and acid halides.

[132] Acid halides are not preferred. However, if an acid halide is used, it is preferably an acid chloride.

[133] Suitable compounds (I) include primary, secondary, tertiary and quaternary amines. Tertiary and quaternary amines form only amine salts.

[134] Secondary amines of the formula HNR3R4 are an especially preferred class of compounds (I). Examples of especially preferred secondary amines include di-octadecylamine, di-cocoamine, tallow amine dihydrogen and methyl behenyl amine. Amine mixtures are also suitable as those derived from natural materials. A preferred amine is a secondary hydrogenated tallow amine, the alkyl groups derived from hydrogenated tallow fat of approximately 3 to 5% by weight of C14, 30 to 32% by weight of C16 and 58 to 60% by weight of C18.

[135] Quaternary amines, of the formula [+ NR3R4R5R6 –An], are an additionally preferred class of compounds (I). R3 and R4 are as defined above (but R4 is not hydrogen). R5 and R6 independently represent a C (1-4) alkyl group, preferably propyl, ethyl or, more preferably, methyl. + NR3R4 (CH3) 2 represents a preferred cation. –An represents the anion. The anion can be any suitable species, but it is preferably a halide, especially a chloride. When (I) comprises a quaternary amine, the reaction conditions can be adjusted to assist the reaction between (I) and (II). Preferably, the reaction conditions are adjusted by the introduction of an auxiliary base. The auxiliary base is preferably a metal alkoxide or metal hydroxide. Alternatively, the quaternary amine salt can be preformed as the corresponding basic salt, for example, a quaternary ammonium hydroxide or alkoxide.

[136] Mixtures of primary and secondary amines or mixtures of secondary and quaternary amines can be supplied as species (I).

[137] Preferred carboxylic acids (II) include carboxylic acids containing two, three or four carboxylic acid groups, and reactive equivalents thereof.

[138] Examples of suitable carboxylic acids and their anhydrides include polycarboxylic aminoalkylene acids, for example, nitrilotriacetic acid, propylene diamine tetraacetic acid, ethylenediamine tetraacetic acid and carboxylic acids based on cyclic skeletons, for example, pyromelitic acid cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid and naphthalene dicarboxylic acid, 1,4-dicarboxylic acids and dialkyl spirobislactones. In general, these acids have about 5 to 13 carbon atoms in the cyclic chemical fraction. Preferred useful acids in the present invention are optionally substituted benzene dicarboxylic acids, for example, phthalic acid, isophthalic acid and terephthalic acid, and their acid anhydrides or acid chlorides. Optional substituents include 1 to 5 substituents, preferably 1 to 3 substituents, independently selected from C (1-4) alkyl, C (1-4) alkoxy, halogen, C (1-4) haloalkyl, C (1-4) ) haloalkoxy, nitrile, -COOH, -CO-OC (1-4) alkyl, and -CONR3R4, where R3 and R4 are independently selected from hydrogen and C (1-4) alkyl. The preferred halogen atoms are fluorine, chlorine and bromine. However, unsubstituted benzene carboxylic acids are preferred. Phthalic acid and its acid anhydride are particularly preferred.

[139] Other suitable compounds of formula (II) are alkyl spirobislactones.

[140] Preferably, the molar ratio between compound (I) and acid, or reactive equivalent thereof (II) is such that at least 50% of the acid groups (preferably at least 75%, preferably at least 90% and more preferably 100%) are reacted in the reaction between compounds (I) and (II), for example, to form the amide and / or amine salt.

[141] When the compound (II) comprises one or more groups of free carboxylic acid, the reaction conditions can be adjusted to allow the reaction between compounds (I) and (II), for example, to form the amide salt or respective amine. Reaction conditions can be adjusted as appropriate using methods known to the person skilled in the art.

[142] In the case of a preferential reaction between a compound (I) and a dicarboxylic acid, or reactive equivalent thereof (for example, acid anhydride) or, preferably, the molar ratio between compound (I) (or mixtures of the compounds (I), in this situation) and acid, or reactive equivalent thereof (or mixed compounds (II), in this situation) is at least 0.7: 1, preferably at least 1: 1, preferably at least 1, 5: 1. Preferably, it is up to 3: 1, preferably up to 2.5: 1. More preferably, it is in the range of 1.8: 1 to 2.2: 1. A molar ratio of 2: 1, (I) to (II) is especially preferred. In another preferred embodiment, a 1: 1 molar ratio is used.

[143] In the case of a preferential reaction between a secondary amine as compound (I) and a dicarboxylic acid, or acid anhydride, preferably the molar ratio between amine (I) and acid or acid (II) anhydride is at least least 1: 1, preferably at least 1.5: 1. More preferably, it is in the range of 1.8: 1 to 2.2: 1. A molar ratio of 2: 1, (I) to (II) is especially preferred.

[144] Preferably, the reaction between the compound (I) and the carboxylic acid, acid anhydride or acid halide (II) forms one or more amide, imide or ammonium salts, combinations of these within the same compound, and mixtures of these compounds.

[145] Thus, in a preferred embodiment, a dicarboxylic acid, acid anhydride or acid halide (II) is reacted with a secondary amine (I), preferably in a molar ratio of 1: 2, so that one mol of the amines form an amide and a mol form an ammonium salt.

[146] An especially preferred additive is a dialkylammonium salt of a monoamide of a dialkylamine and phthalic acid, which is suitably the reaction product of tallow di (hydrogenated) amine (I) and phthalic acid or its acid anhydride (II ); preferably in a 2: 1 molar ratio.

[147] An especially preferred anti-wax wax additive is the reaction product of tallow di (hydrogenated) amine (I) and phthalic acid or its acid (II) anhydride; preferably in a 1: 1 molar ratio.

[148] Other preferred wax antideposition additives are the reaction products of tallow (hydrogenated) amine (I) with EDTA (II); preferably in a molar ratio of 4: 1 with the removal of four moles of water or two moles of water to form, respectively, the tetra-amide derivative or the diamide diamide salt derivative.

[149] Another preferred additive is the reaction product of an alkyl spirobislactone (II), for example, dodecenyl spirobislactone, with mono-sebum amine and / or di-sebum amine (I); preferably the reaction product of one mole of alkyl-spirobislactone, for example, dodecenyl-spirobislactone with one mole of mono-tallow amine and one mole of di-tallow amine.

[150] Another preferred additive is the reaction product of the benzene-1,2,4,5-tetracarboxylic acid reaction product or its dianhydride (II) with tallow di (hydrogenated) amine (I); preferably in a molar ratio of 1: 4. This reaction product can be called pyromelitic tetra-amide, but in fact, it can typically be a mixture of tetra-amide, triamide / monosal and diamide / dishal.

[151] Another suitable wax antideposition additive is the semiamonium semiamide salt of a maleic anhydride α-alefin copolymer, where α-olefin has 10 to 36 carbon atoms, preferably 12 to 24 carbon atoms, for example, 16 to 20 carbon atoms. The amine reacted with the maleic anhydride α-olefin copolymer is suitably a dialkylamine in which the alkyl group has 6 to 30, preferably 12 to 24, for example, 18 carbon atoms. Such an additive can be formed, for example, according to the following reaction scheme:

[152] Another class of wax antideposition additives that may be useful in this document are alkylphenol aldehyde resins modified by a Mannich reaction with an alkylamine. These compounds are adequately formed by the formation of an alkylphenol condensate with an aldehyde and then by the reaction of the condensate in a Mannich reaction with an alkylamine and an aldehyde or ketone (preferably and aldehyde). Alkylphenol is suitably monosubstituted by an alkyl group with 1 to 30 carbon atoms; the aldehyde used to prepare the resin preferably has 1 to 4 carbon atoms. Preferably, the alkylamine preferably includes a primary amine group and has 12 to 24 carbon atoms. An aldehyde with 1 to 4 carbon atoms, preferably formaldehyde, is used in the Mannich reaction. These compounds are described in more detail in the US document

9169452.

[153] Preferred medium (y) distillate flow improvers are copolymers of ethylene and an olefinically unsaturated compound.

[154] The preferred copolymers of ethylene and olefinically unsaturated compounds for use in the present invention are those that, in addition to ethylene, contain 1 to 23 mol%, preferably 6 to 21 mol%, more preferably 7 to 18 mol% , suitably 9 to 16 mol%, especially 10 to 15 mol%, of olefinically unsaturated compounds as comonomers.

[155] The olefinically unsaturated compounds are preferably vinyl ethers, acrylic ethers, methacrylic esters, alkyl vinyl ethers and / or alkenes, and the compounds mentioned can be replaced by hydroxyl groups. One or more comonomers may be present in the polymer.

[156] The vinyl ethers are preferably those of the formula (1): CH2-CH-OCOR7 (1) where R7 is C1 to C30 alkyl group. In some embodiments, R7 may be a C4 to C16 alkyl group, for example, C6 to C12 alkyl groups. In some embodiments, the alkyl groups can be replaced by one or more hydroxyl groups. In preferred embodiments, R7 is a C1 to C10 alkyl group, more preferably a C1 to C4 alkyl group, more preferably a C1 to C2 alkyl group.

[157] Suitable vinyl ethers include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl pivalate, vinyl 2-ethyl hexanoate, vinyl laurate vinyl, vinyl stearate and esters of verstics like vinyl neononanoate, vinyl neodecanoate, vinyl neoundecanoate. An especially preferred vinyl ether is vinyl acetate.

[158] In some embodiments, these ethylene copolymers may contain vinyl acetate and at least one additional vinyl ether of formula (1), where R7 is C4 to C30 alkyl, preferably C4 to C16 alkyl, especially C6 to C12 alkyl.

[159] In preferred embodiments, the compound of formula (1) is vinyl acetate and the medium distillate flow enhancer (y) comprises a copolymer of ethylene and vinyl acetate. Preferably, the copolymer comprises 76 to 63% by weight of ethylene and 24 to 37% by weight of vinyl acetate, more preferably from 74 to 65% by weight of ethylene and 26 to 35% by weight of vinyl acetate.

[160] Acrylic esters are preferably those of formula (2): CH2-CR8-COOR9 (2) where R8 is hydrogen or methyl and R9 is C1 to C30 alkyl, preferably C4 to C16 alkyl, especially C6 to C12 alkyl. Suitable acrylic esters include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ne isobutyl acrylate, hexyl, octyl, 2-ethylhexyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl (meth) acrylate and mixtures of these comonomers. In an additional embodiment, the mentioned alkyl groups can be replaced by one or more hydroxyl groups. An example of such an acrylic ester is hydroxyethyl methacrylate.

[161] Alkylvinyl ethers are preferably compounds of the formula (3): CH2-CH-OR10 (3) wherein R10 is C1 to C30 alkyl, preferably C4 to C16 alkyl, especially C6 to C12 alkyl. Examples include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether. In an additional embodiment, the mentioned alkyl groups can be replaced by one or more hydroxyl groups.

[162] Alkenes are preferably monounsaturated hydrocarbons having 3 to 30 carbon atoms, especially 4 to 16 carbon atoms and especially 5 to 12 carbon atoms. Suitable alkenes include propene, butene, isobutylene, pentene, hexene, 4-methylpentene, octene, diisobutylene and norbornene and derivatives thereof such as methylnorbornene and vinylnorbornene. In an additional embodiment, the mentioned alkyl groups can be replaced by one or more hydroxyl groups.

[163] In some embodiments, the medium (y) distillate flow enhancer may comprise a terpolymer comprising ethylene, vinyl acetate and an additional monomer, for example, a long-chain vinyl ether or a longer-chain alkene.

[164] In addition to ethylene, some particularly preferred terpolymers contain 1 to 23 mol%, preferably 3 to 20 mol%, especially 8 to 15 mol%, of vinyl acetate, and 0.1 to 12 mol% , especially 0.2 to 5 mol%, of at least one relatively long chain vinyl ether and preferably branched vinyl ether, for example, vinyl 2-ethylhexanoate, vinyl neononanoate or vinyl neodecanoate, where the The total comonomer content of the terpolymers is preferably between 8 and 21 mol%, especially between 12 and 18 mol%. Other preferred copolymers contain, in addition to ethylene and 8 to 18 mol% of vinyl ethers of C2 to C12 carboxylic acids, also 0.5 to 30 mol%, preferably 0.5 to 10 mol%, of olefins such as propene , butene, isobutylene, hexene, 4-methylpentene, octene, diisobutylene and / or norbornene.

[165] In some embodiments, preference is given to the use of mixtures of two or more of the ethylene copolymers mentioned above. Most preferably, the polymers on which the blends are based differ in at least one characteristic. For example, they can contain different comonomers, or have different comonomer contents, molecular weights and / or degrees of branching.

[166] Most preferably, the medium (y) distillate flow improvers are copolymers of ethylene and vinyl acetate.

[167] Preferably, the weight ratio between the wax antideposition additive (x) and the medium distillate flow enhancer (y) present in component (b) is 10: 1 to 1:10, preferably from 5: 1 to 1:10, more preferably from 2: 1 to 1:10, more preferably from 1: 1 to 1:10.

[168] The above ratios are calculated based on the active amounts of all wax antideposition additives (x) and all medium distillate flow enhancers (y) present in component (b).

[169] The additive composition of the third aspect comprises component (b) and additive (c).

[170] The weight ratio between additive (c) and component (b) is preferably from 1: 100 to 1: 1, more preferably from 1:40 to 1: 2, suitably from 1:20 to 1: 3.

[171] Preferably, the additive composition of the third aspect comprises a wax antideposition additive (x), a medium distillate flow enhancer (y) and a copolymer additive (c).

[172] Preferably, the additive composition of the third aspect comprises (by weight) from 10 to 40 parts of wax antideposition additive (x); 50 to 88 parts of the medium distillate flow enhancer (y) and 2 to 20 parts of copolymer additive (c), based on the total active weight of (x), (y) and (c).

[173] The additive composition of the third aspect also adequately comprises a diluent or carrier. Suitable diluents and carriers will be known to the person skilled in the art and include, for example, solvents, especially aromatic and aliphatic organic solvents and mixtures thereof.

[174] The additive composition of the third aspect may also contain additional additives to improve the handling, for example, of esters, carboxylic acids and alcohols.

[175] The medium distillate fuel composition of the fourth aspect of the present invention comprises component (a), component (b) and additive (c).

[176] Suitably, component (a) is present in the medium distillate fuel composition in an amount of at least 0.1 ppm, preferably at least 1 ppm, more preferably at least 10 ppm, suitably at least 30 ppm, for example, at least 50 ppm.

[177] Suitably, component (a) is present in the medium distillate fuel composition in an amount up to 10,000 ppm, preferably up to 1,000 ppm, more preferably up to 500 ppm, for example, up to 250 ppm or up to 200 ppm .

[178] Suitably, component (b) is present in the medium distillate fuel composition in an amount of at least 1 ppm, preferably at least 10 ppm, more preferably at least 50 ppm, suitably at least 80 ppm.

[179] Suitably, component (b) is present in the fuel composition of medium distillate in an amount of up to

10,000 ppm, preferably up to 5,000 ppm, more preferably up to 1,000 ppm, for example, up to 500 ppm, up to 400 ppm or up to 350 ppm.

[180] Suitably, the wax antideposition additive (x) is present in the medium distillate fuel composition in an amount of at least 0.1 ppm, preferably at least 1 ppm, more preferably at least 5 ppm, properly at least 10 ppm.

[181] Suitably, the wax antideposition additive (x) is present in the medium distillate fuel composition in an amount of up to 10,000 ppm, preferably up to 1,000 ppm, more preferably up to 500 ppm, for example, up to 200 ppm or up to 100 ppm.

[182] Suitably, the medium distillate flow enhancer (y) is present in the medium distillate fuel composition in an amount of at least 0.1 ppm, preferably at least 1 ppm, more preferably at least 10 ppm , suitably at least 50 ppm, for example, at least 60 ppm.

[183] Suitably, the medium distillate flow enhancer (y) is present in the medium distillate fuel composition in an amount of up to 10,000 ppm, preferably up to 1,000 ppm, more preferably up to 500 ppm, for example, up to 350 ppm or up to 300 ppm.

[184] Suitably, the additive (c) is present in the medium distillate fuel composition in an amount of at least 0.1 ppm, preferably at least 1 ppm, more preferably at least 5 ppm.

[185] Suitably additive (c) is present in the fuel composition of medium distillate in an amount of up to 10,000 ppm, preferably up to 1,000 ppm, more preferably up to 500 ppm, suitably up to 200 ppm, for example, up to 100 ppm or up to 60 ppm

[186] Each of the components (a), (b) (x), (y) and (c) can contain a mixture of compounds. For the avoidance of doubt, the above amounts refer to the total amount of additives (a), (b) (x), (y) and (c), respectively, present in the composition.

[187] Unless otherwise specified, all amounts of additive referred to in this document refer to the amount of active material present in the composition and all parts per million (ppm) are by weight.

[188] In preferred embodiments, the fuel composition of the present invention comprises from 10 to 250 ppm, preferably component (a) from 30 to 200 ppm; from 40 to 400 ppm, preferably component (b) from 50 to 350 ppm; and from 1 to 100 ppm, preferably additive (c) from 5 to 60 ppm.

[189] The base fuel used in the present invention may comprise or consist of a petroleum-based medium distillate fuel oil. These medium distillate fuel oils generally boil within the range of 110 ºC to 500 ºC, for example, 150 ºC to 400 ºC. The medium distillate fuel oil may comprise atmospheric distillate or vacuum distillate, cracked diesel or a mixture in any proportion of refinery streams and direct distillation from conversion units, such as thermally and / or catalytically cracked and hydro-cracked distillates.

[190] The fuel composition of the present invention may comprise or consist of non-renewable Fischer-Tropsch fuels, such as those described as GTL fuels (gas to liquid), CTL fuels (coal to liquid) and OTL (oil sands to liquid).

[191] The fuel composition may comprise first generation biofuel. The first generation biofuel contains esters of, for example, vegetable oils, animal fats and fats used in cooking. This form of biofuel can be obtained by transesterification of oils, for example, rapeseed oil, soybean oil, safflower oil, palm oil, corn oil, peanut oil, cottonseed oil, tallow, coconut oil , physic nut oil (Jatropha), sunflower oil seed, used cooking oils, hydrogenated vegetable oils or any mixture thereof, with an alcohol, usually a mono-alcohol, in the presence of a catalyst.

[192] These first generation biofuels can be called fatty acid alkyl esters (FAAEs), preferably fatty acid methyl esters (FAMEs).

[193] The fuel composition may comprise second generation biofuel. The second generation biofuel is derived from renewable resources such as vegetable oils and animal fats and processed, often at the refinery, often using hydroprocessing, such as the H-Bio process developed by Petrobras. Second generation biofuel can be similar in properties and quality to petroleum-based fuel flows, for example, renewable fuel produced from vegetable oils, animal fats, etc., and marketed by ConocoPhillips as Renewable Diesel and Neste as NExBTL.

[194] The fuel composition of the present invention can comprise third generation biofuel. The third generation biofuel uses gasification and Fischer-Tropsch technology, including those described as BTL fuels (biomass for liquid). The third generation biofuel does not differ much from some second generation biofuel, but aims to exploit the entire plant (biomass) and, thus, expands the raw material base.

[195] The fuel composition may contain mixtures of any or all of the above fuel compositions.

[196] In some embodiments, the fuel composition of the present invention can be a mixed fuel comprising biofuel, and a second fuel. In these mixtures, the biofuel can be present in an amount of 0.1% to 99% (vol / vol), preferably from 0.1 to 25%. In these mixtures, the biofuel component may include a mixture of first generation biofuel and second generation biofuel. The first generation biofuel preferably FAAEs, especially FAMEs, adequately supplies from 0.1 to 25% (vol / vol), preferably 0.1 to 20%, more preferably 0.1 to 12%, for example, 0, 1 to 10% of the fuel composition. The second fuel can be a petroleum-based fuel oil, especially a medium distillate fuel oil, including a non-renewable Fischer-Tropsch fuel.

[197] All of these fuels can be used in the modalities of the invention.

[198] In some embodiments, the fuel composition of the present invention may comprise a petroleum-based medium distillate fuel oil and optionally from 0.1% to 25% (vol / vol) of a biofuel, wherein the composition of fuel optionally comprises from 0.1% to 12% (vol / vol) of FAAEs.

[199] The fuel composition of the present invention may contain a relatively high sulfur content, for example, greater than 0.05% by weight, such as 0.1% or 0.2%, 0.5% or more.

[200] However, in preferred embodiments, the fuel has a sulfur content of a maximum of 0.05% by weight, more preferably of a maximum of 0.035% by weight, especially of a maximum of 0.015%. Fuels with even lower levels of sulfur are also suitable, such as fuels with less than 50 ppm of sulfur by weight, preferably less than 20 ppm, for example, 10 ppm or less.

[201] The fuel composition of the present invention can be used as a fuel for locomotion in motor vehicles, ships and boats; as a fuel burner in domestic heating and power generation and as a fuel in multifunctional stationary engines.

[202] The fuel composition may include one or more additional additives, such as those that are commonly found in fuels for use in this invention. These include, for example, antioxidants, other dispersants and / or detergents, cetane improvers, degreasers, stabilizers, demulsifiers, defoamers, corrosion inhibitors, lubricity improvers, dyes, markers, combustion improvers and odor masks, and other additives useful for achieving improvements in cold temperature performance.

[203] In preferred embodiments of the present invention, component (a) is selected from one or more of: a quaternary ammonium salt additive formed by the reaction of a quaternizing agent and the reaction product of an acylating agent substituted by hydrocarbyl and a compound comprising at least one tertiary amine group and a primary amine group, secondary amine or alcohol; the product of a Mannich reaction between a hydrocarbyl-substituted phenol, formaldehyde and a polyamine; and the reaction product of an acylating agent derived from succinic acid replaced by hydrocarbyl and an amine; component (b) comprises: a copolymer of ethylene and vinyl acetate; and the reaction product of (I) a compound containing the –NR3R4 segment where R3 represents a group containing 4 to 44 carbon atoms and R4 represents a hydrogen atom or an R3 group, and (II) a carboxylic acid with 1 to 4 groups of carboxylic acid or an acid anhydride or acid halide thereof; and the additive (c) comprises a copolymer of vinyl acetate and monomers of formula (D): (D) where each of R1 and R2 is an alkyl group with less than 18 carbons.

[204] In the present invention, the copolymer additive (c) improves the low temperature properties of the medium distillate fuel composition.

[205] Preferably, the additive reduces the CP value as measured by a short sediment test.

[206] A number of short sediment tests are known. However, all of these seek to minimize the difference between the mist point (CP) of the bottom portion of a fuel and another portion of the fuel or added fuel base (CP).

[207] Suitably, the copolymer additive (c) provides CP in a short sediment test less than 5 ° C, preferably less than 3 ° C, more preferably less than 2 ° C. Suitably, a CP below 3 ° C, preferably below 2 ° C is provided according to the short sediment test protocol described in example 2, procedure A.

[208] Preferably, the copolymer additive (c) improves the low temperature properties of the medium distillate fuel composition by influencing antagonistic interaction between component (a) and component (b).

[209] According to a fifth aspect of the present invention, the use of an additive (c) which is a copolymer comprising units of formula (A): (A) and units of formula (B) is provided:

(B) where R is an alkyl group and each of R1 and R2 is an alkyl group; to improve an antagonistic interaction in a medium distillate fuel composition between (a) a nitrogen-containing dispersant; and (b) one or more low temperature property enhancers that are not vinyl ether copolymers and that are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof.

[210] It is understood that improving the antagonistic interaction in a medium distillate fuel composition refers to preventing and / or inhibiting the antagonistic effect and / or providing an additional effect that neutralizes the antagonism. Thus, the addition of the copolymer additive (c) can prevent or reduce negative interactions between component (a) and component (b) or can provide an additional effect, which means that antagonistic interactions between component (a) and component (b) do not have such a negative effect on the low temperature properties of the fuel.

[211] Suitably, the addition of the copolymer additive (c) improves the low temperature properties of the medium distillate fuel composition as measured by the Short Pellet Test (SST). This test is suitably as described in Example 2, procedure A. Suitably, the improvement in performance is measured by a reduction in the CP value. Suitably, a CP below 3 ° C, preferably below 2 ° C is provided according to the short sediment test protocol described in example 2, procedure A.

[212] Thus, the present invention can further provide the use of copolymer additive (c) as defined herein to improve the performance of the Short Pellet Test of a medium distillate fuel composition comprising: a nitrogen-containing dispersant; and one or more low temperature property enhancers selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof.

[213] Advantageously, the copolymer additive (c) is highly effective in improving antagonistic interactions between component (a) and component (b) even at low treatment rates. Thus, the present invention can provide for the use of less than 120 ppm of a copolymer additive (c) to improve antagonistic interactions between component (a) and component (b) in a medium distillate fuel composition.

[214] Suitably, the invention can provide the use of less than 100 ppm of additive (c) to improve the antagonistic interaction between component (a) and component (b) in a medium distillate fuel composition.

[215] In some embodiments, the present invention may provide the use of less than 75 ppm or less than 50 ppm of additive (c) to improve antagonistic interactions between component (a) and component (b) in a composition of distillate fuel.

[216] The invention will now be described further with reference to the following non-limiting examples. EXAMPLES

[217] In the examples, the following additives are dosed in medium distillate fuels: A - a copolymer of ethylene vinyl acetate comprising 30 to 32% by weight of vinyl acetate units and having an average numerical MW of approximately 4 to 5,000 supplied in aromatic solvent.

B - the reaction product of 2 moles of tallow di amine (hydrogenated) and 1 mole of phthalic anhydride reacted to form the semi-ammonium salt supplied in aromatic solvent.

C - a copolymer of a ratio of 1: 1 mol of vinyl acetate and the diester of fumaric acid and tetradecanol with an average numerical MW of approximately 10,000 supplied in aromatic solvent.

D - the reaction product of a polyisobutenyl succinic anhydride with a numerical average molecular weight GDP of 750 and a mixture of polyethylene polyamines corresponding to tetraethylenepentamine reacted to form the succinized polyisobutylene supplied in aromatic solvent.

E - the Mannich reaction product of dodecyl phenol, formaldehyde and ethylene diamine supplied in an aromatic solvent.

F - the reaction product of a succinic anhydride replaced by polyisobutene with a numerical average molecular weight of 1,000 and dimethylamino propylamine reacted to form an imide and then quaternized by reaction with methyl salicylate supplied in aromatic solvent.

G - a copolymer of ethylene vinyl acetate that comprises 28% by weight of vinyl acetate units and with an average numerical MW of approximately 3 to 4,000 supplied in aromatic solvent.

H - a copolymer of a ratio of 1: 1 mol of vinyl acetate and the diester of fumaric acid and tetradecanol with an average numerical MW of approximately 21,000 supplied in aromatic solvent.

I (Comparative) - a copolymer of an α-olefin and behenyl maleate supplied in an aromatic solvent.

J (Comparative) - C16 / 18 diester of C24 / 26 alpha-olefin maleic anhydride copolymer supplied in aromatic solvent.

K (Comparative) - a C16 / C18 alkyl imide of C14 / C16 α-olefin maleic anhydride copolymer supplied in aromatic solvent.

L - a copolymer of a ratio of 1: 1 mol of vinyl acetate and the diester of fumaric acid and dodecanol with an average numerical MW of approximately 30,000 supplied in aromatic solvent. M - a copolymer of a ratio of 1: 1 mol of vinyl acetate and the diester of fumaric acid and dodecanol with an average numerical MW of approximately 33,000 supplied in aromatic solvent. Example 1

[218] Fuel compositions were prepared by adding the quantities as specified in Table 4 and Table 5 to a fuel composition as described below.

[219] Compositions 1 to 10 were prepared in Fuel 1, in which a medium distillate fuel composition has a specification that corresponds to EN 590 and with the properties shown in Table 1.

[220] Compositions 11 and 12 were prepared in Fuel 2, in which a medium distillate fuel composition has a specification that corresponds to EN 590 and with the properties shown in Table 2.

[221] Compositions 13 to 16 were prepared in Fuel 3, in which a medium distillate fuel composition has a specification that corresponds to EN 590 and with the properties shown in Table 3 mixed with 7% by volume of methyl acid ester fatty to give a fuel having a mist point of -9 ° C and CFPP of -9 ° C.

Table 1 - Fuel Properties 1 Results Density Units Test g / cm3 0.8386 Mist point ° C -6 CFPP ° C -8 Distillation IBP ° C 170.6 10% ° C 195.7

20% ° C 208.3 30% ° C 226.1 40% ° C 243.8 50% ° C 261.2 60% ° C 279.5 70% ° C 298.3 80% ° C 316.5 90 % ° C 335.3 FBP ° C 358.8

Table 2 - Fuel Properties 2 Test Units Results Density g / cm3 0.8312 Fog point ° C -8.5 CFPP ° C -10 Distillation IBP ° C 166 10% ° C 205 20% ° C 223 30% ° C 237 40% ° C 251 50% ° C 267 60% ° C 283 70% ° C 299 80% ° C 317 90% ° C 338 FBP ° C 362

Table 3 - Fuel Properties 3 Test Units Results Density g / cm3 0.8312 Mist point ° C -7.5 CFPP ° C - 10 Distillation IBP ° C 168 10% ° C 205 20% ° C 221 30% ° C 237 40% ° C 251 50% ° C 267 60% ° C 282

70% ° C 299 80% ° C 317 90% ° C 338 FBP ° C 360 Table 4 Additive concentration (active ppm) Composition ABCDEFG 1 280 62.4 0 180 0 0 0 2 280 62.4 0 0 195 0 0 3 280 62.4 0 0 0 180 0 4 280 62.4 50 180 0 0 0 5 280 62.4 20 0 195 0 0 6 280 62.4 20 0 0 180 0 7 280 62.4 0 0 61.7 69.0 0 8 280 62.4 20 0 61.7 69.0 0 9 280 62.4 0 0 26.0 36.0 0 10 280 62.4 20 0 26.0 36.0 0 11 0 14, 4 0 0 26.0 36.0 69.1 12 0 14.4 5 0 26.0 36.0 69.1 Table 5 Additive concentration (active ppm)

I

JK Composition BGEFH with LM comp p 13 24.0 115.2 61.7 69.0 10 14 24.0 115.2 61.7 69.0 10 15 24.0 115.2 61.7 69.0 10 16 24.0 115.2 61.7 69.0 10 17 24.0 115.2 61.7 69.0 10 18 24.0 115.2 61.7 69.0 10 Example 2

[222] Fuel compositions 1 to 17 were tested in a short sediment test according to procedure A and / or procedure B. The results are shown in Table 6.

[223] Procedure 450 g of fuel base are mixed with the appropriate amount of additive and the mist point of the treated fuel is determined. 500 ml of the treated fuel is transferred to a 500 ml measuring cylinder and cooled in a climatic chamber or cooling bath until the test temperature and maintained at that temperature for 16 hours. After the 16-hour period, the upper 80% and lower 20% of the fuel are separated and heated to redissolve the precipitated wax. The cloud point of the two portions is determined. CP is recorded as the difference between the fog point of the upper 80% and the lower 20% of the fuel.

[224] Procedure B 150 g of fuel base are mixed with the appropriate amount of additive and stored at 40 ° C for one hour. 100 ml are transferred to a 100 ml graduated cylinder. The fog point of the treated fuel is determined. The sample is cooled in a cooling bath / climatic chamber to the test temperature and then maintained at that temperature for 16 hours. After the 16-hour period, the fuel appears and the amount of sediment is recorded. The top 50% and bottom 50% of the fuel are separated and the bottom 50% are stored at 40 ° for 1 hour and the fog point is determined. ΔCP is recorded as the difference between the fog point of the lower 50% portion of the fuel and the original fog point of the treated fuel before cooling.

Table 6 (C) (C) - (C) - (B) (A) Layer (B) (A) Temp.

Bottom Fuel Background Composition Procedure (° C) of top Appearance Sediment Result treated at CP to CP ΔCP ΔCP test at CP (° C) (° C) (° C) (° C) (° C) 1 A -13 -5.3 -8.3 -0.3 8.0 Fail 2 A -13 -5.2 -8.0 -0.2 7.8 Fail 3 A -13 -6.1 -7.1 -1 , 0 6.1 Failed 4 A -13 -6.4 -7.3 -5.2 2.1 Approved 5 A -13 -6.4 -6.8 -5.6 1.2 Approved 6 A -13 -6.1 -6.6 -5.2 1.4 Passed 7 A -13 -5.9 -6.6 -0.9 5.7 Failed 8 A -13 -6.4 -6.8 -5 , 2 1.6 Approved 9 A -13 -5.2 -6.7 -1.2 5.5 Failed 10 A -13 -6.0 -6.3 -5.4 0.9 Approved 11 B -14.5 -8.5 -4.5 4.0 clear 16 ml Failed 12 B -14.5 -8.5 -7.5 1.0 cloudy none Approved 12 A -14.5 -8.5 -8.0 -7.0 1 , 0 cloudy none Approved 13 B -15 -8.5 -8.0 0.5 cloudy none Approved 14 B -15 -8.0 -3.0 5.0 flocculated 28 ml Failed 15 B -15 -8.5 -4.0 4.5 flocculated 26 ml Failed 16 B -15 -9.0 -4.5 4.5 almost clear 10 ml Failed 17 B -15 -8.0 -8.0 0.0 blurred strokes Approved 18 B -15 -8.0 -7.5 0.5 blurred strokes Approved

Claims (16)

1. Method for improving the low temperature properties of a medium distillate fuel composition characterized by the fact that it comprises: (a) a nitrogen-containing dispersant; and (b) one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof; wherein the method comprises adding to the fuel an additive (c) which is a copolymer comprising units of formula (A): (A) and units of formula (B): (B) where R is an alkyl group and each of R1 and R2 is an alkyl group. 2. Use of (c) a copolymer characterized by the fact that it comprises units of formula (A): (A) and units of formula (B): (B) where R is an alkyl group and each of R1 and R2 is an alkyl group; to improve the low temperature properties of a medium distillate fuel composition comprising: (a) a nitrogen-containing dispersant; and (b) one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof. 3. Additive composition to improve the low temperature properties of a medium distillate fuel composition, where the additive composition is characterized by the fact that it comprises: (b) one or more low temperature property enhancers that are not vinyl ester fumarate copolymers that are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof; and (c) a copolymer comprising units of formula (A): (A) and units of formula (B): (B) where R is an alkyl group and each of R1 and R2 is an alkyl group. 4. Medium distillate fuel composition characterized by the fact that it comprises: (a) a nitrogen-containing dispersant; (b) one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof; and (c) a copolymer comprising units of formula (A): (A) and units of formula (B): (B) where R is an alkyl group and each of R1 and R2 is an alkyl group. 5. Method, use or composition, according to any one of the preceding claims, characterized by the fact that the additive (c) is prepared by the copolymerization of vinyl ester monomers and dialkyl fumarate monomers. 6. Method, use or composition, according to any of the preceding claims, characterized by the fact that R is methyl. 7. Method, use or composition according to any one of the preceding claims, characterized by the fact that each of R1 and R2 is an alkyl group with less than 18 carbon atoms. 8. Method, use or composition, according to any one of the preceding claims, characterized by the fact that component (a) is selected from: (i) a quaternary ammonium salt additive; (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; (iii) the reaction product of an acylating agent derived from carboxylic acid and an amine; (iv) the reaction product of an acylating agent derived from carboxylic acid and hydrazine; (v) a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine; (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine or salt compound whose product comprises at least one triazole amino group; and (vii) an alkylene-substituted amine. 9. Method, use or composition, according to any one of the preceding claims, characterized by the fact that component (a) is selected from: (i) a quaternary ammonium salt additive; (ii) the product of a Mannich reaction between an aldehyde, an amine and an optionally substituted phenol; and (iii) the reaction product of an acylating agent derived from carboxylic acid and an amine. 10. Method, use or composition, according to any one of the preceding claims, characterized by the fact that component (a) is selected from one or more of: - a quaternary ammonium salt additive formed by the salicylate reaction of methyl or dimethyl oxalate with the reaction product of a succinic anhydride substituted by polyisobutylene with a numerical average molecular weight of 700 to 1,300 GDP and dimethylaminopropylamine; - the Mannich reaction product of dodecylphenol, formaldehyde and ethylene diamine or tetraethyl pentamine; and - the reaction product of a polyisobutenyl-substituted succinic acid / anhydride with a molecular weight (Mn) of GDP of 500 to 1,300 and a polyethylene polyamine with 1 to 9 amino groups and 1 to 8 ethylene groups. 11. Method, use or composition according to any one of the preceding claims, characterized by the fact that component (b) comprises at least one wax antideposition additive (x) and at least one medium distillate flow enhancer ( y). 12. Method, use or composition according to any one of the preceding claims, characterized by the fact that component (b) comprises a wax antideposition additive (x) which is the reaction product of (I) a compound containing the –NR3R4 segment where R3 represents a group containing 4 to 44 carbon atoms and R 4 represents a hydrogen atom or a group R3, and (II) a carboxylic acid with 1 to 4 groups of carboxylic acid or a reactive equivalent thereof. 13. Method, use or composition according to any one of the preceding claims, characterized by the fact that component (b) comprises a wax antideposition additive (x) which is the reaction product of tallow di (hydrogenated amine) ) (I) and phthalic acid or its acid (II) anhydride. 14. Method, use or composition according to any one of the preceding claims, characterized in that component (b) comprises a medium distillate flow enhancer (y) which is an ethylene copolymer and an olefinically unsaturated compound. 15. Method, use or composition, according to any one of the preceding claims, characterized by the fact that component (b) comprises a medium distillate flow enhancer (y) which, in addition to ethylene, contains 1 to 23% in mol, of olefinically unsaturated compounds as comonomers. 16. Use of an additive (c) characterized by the fact that it is a copolymer comprising units of formula (A): (A) and units of formula (B): (B) where R is an alkyl group and each of R1 and R2 is an alkyl group; to improve an antagonistic interaction in a medium distillate fuel composition between (a) a nitrogen-containing dispersant; and (b) one or more low temperature property enhancers that are not vinyl ester fumarate copolymers and that are selected from (x) wax antideposition additives; (y) medium distillate flow improvers and mixtures thereof.