CN112424318A

CN112424318A - Compositions, uses and methods for improving low temperature performance of middle distillate fuels

Info

Publication number: CN112424318A
Application number: CN201980044513.3A
Authority: CN
Inventors: T·迈尔
Original assignee: Innospec Ltd
Current assignee: Innospec Ltd
Priority date: 2018-07-02
Filing date: 2019-07-01
Publication date: 2021-02-26
Also published as: CA3102929A1; BR112020026651A2; AU2019298748A1; EP4234661A2; GB201909486D0; EP3818133A1; WO2020008182A1; EP4234661A3; US20210277320A1; KR20210027403A; GB2576614A; HRP20231221T1; HUE063463T2; GB201810852D0; GB2576614B; PL3818133T3; SG11202012146SA; EP3818133B1

Abstract

A method of improving the low temperature properties of a middle distillate fuel composition comprising: (a) a nitrogen-containing dispersant; and (b) one or more low temperature performance enhancing agents which are not fumarate vinyl ester copolymers and are selected from (x) wax anti-settling additives, (y) middle distillate flow improvers and mixtures thereof; the method comprises adding to the fuel an additive (c) which is a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl and R¹And R²Each is an alkyl group.

Description

Compositions, uses and methods for improving low temperature performance of middle distillate fuels

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

The low temperature properties of fuels have been studied extensively and it is common practice and in many countries to force this to be done by introducing additives into the fuel to prevent problems when storing the fuel at low temperatures.

Standardized tests have been designed to measure various low temperature properties of middle distillate fuels, including the temperature at which the fuel becomes cloudy (cloud point-CP), the minimum temperature at which the fuel can flow (pour point-PP), and the Cold Filter Plugging Point (CFPP).

The cloud point of a fuel is the temperature at which a wax crystal cloud first appears in a liquid when the fuel is cooled under specified conditions, for example as determined by the test method defined in ASTM D2500.

At temperatures below the cloud point but above the pour point, the wax crystals can reach a size and shape that can plug fuel lines, screens, and filters, even if the fuel is to physically flow. These problems are recognized in the art and have many recognized test methods such as CFPP values (cold filter plugging point, determined according to DIN EN 116).

Tests such as these were introduced to give an indication of low temperature operability, as the cloud point tests were considered too conservative.

Fuel additives in the form of cold flow improvers (CFI, also known as middle distillate flow improvers or MDFI) and wax anti-settling additives (WASA) have been designed to ameliorate the problem of precipitation in fuels at low temperatures and these additives have conventionally been added to middle distillate fuels.

Some of these additives may help to keep so-called "waxes" in solution in fossil fuels; others may vary their crystal morphology or size so that filterability and pourability are maintained despite precipitation. Other additives may be used to prevent settling of the precipitated wax during storage.

In general, these additives have been found to be very successful to the extent that these fuels can be used even under severe low temperature conditions with suitable addition. In many fuels, the CFPP value can be reduced by 10-20 ℃ compared to the corresponding fuel without the additive.

Therefore, it is common practice to include additives that improve low temperature performance, such as WASA and/or MDFI, in middle distillate fuels. Additive packages containing a combination of WASA and MDFI are also common and are referred to as WAFI.

The Short Segment Test (SST) measures the propensity of the wax content of fuel oils to settle and can be used to determine the effectiveness of a wax anti-settling additive or combination of additives. In the test, the Cloud Point (CP) of the base fuel was measured. The additive(s) under study were added to the base fuel and the samples were stored at a specific temperature (typically 7 ℃ below the measured CP) for 16 hours. The amount of wax that has settled, as judged by eye, can be recorded. The bottom 20% of the fuel is then taken and the CP of this sample is measured and compared to the CP of the base fuel or the top 80% depending on the particular test conditions. The difference (Δ CP) between the base fuel or top 80% CP and the bottom 20% CP of the additized fuel is a measure of the extent of wax settling. Low Δ CP values, preferably about zero, indicate good wax dispersion. Low levels of deposition can be used as an additional measure of good wax dispersion.

It is also common practice to include nitrogen-containing detergent/dispersant compounds in middle distillate fuels. These are necessary to ensure engine cleanliness 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.

However, in certain middle distillate fuels, antagonistic interactions (anti-fouling interactions) may occur between the nitrogen-containing detergent and the wax anti-settling additive and/or middle distillate flow improver, which affect the low temperature performance of the fuel.

The antagonistic action results in poorer wax dispersion on storage, resulting in unexpectedly poor performance of the fuel when stored at low temperatures. This effect can be observed in a short deposition test (SST).

The antagonistic action between detergent and WASA/MDFI is a phenomenon widely known in the art. However, it does not occur in all fuels and it is difficult to predict whether it will occur in a particular fuel.

A number of solutions to this problem have been proposed and various additives have been described which can be used to improve the negative interaction, see for example EP1932899, US8021444, US8153567, US8628590, US8628591, US8734542, US20100154294, US20100180492 and US 20100236139.

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

According to a first aspect of the present invention there is provided a method of improving the low temperature performance of a middle distillate fuel composition comprising:

(a) a nitrogen-containing dispersant; and

(b) one or more low temperature performance enhancers (low temperature performance enhancers) that are not fumarate vinyl ester copolymers (fumarate vinyl ester copolymers) and are selected from: (x) Wax anti-settling additives, (y) middle distillate flow improvers and mixtures thereof;

the method comprises adding to the fuel an additive (c) which is a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl and R¹And R²Each is an alkyl group.

According to a second aspect of the present invention there is provided the use of a copolymer (c) comprising units of formula (a) and units of formula (B) to improve the low temperature properties of a middle distillate fuel composition:

wherein R is alkyl and R¹And R²Each is an alkyl group;

the middle distillate fuel composition comprises:

(a) a nitrogen-containing dispersant; and

(b) one or more low temperature performance enhancing agents which are not fumarate vinyl ester copolymers and are selected from: (x) Wax anti-settling additives, (y) middle distillate flow improvers, and mixtures thereof.

According to a third aspect of the present invention there is provided an additive composition for improving the low temperature performance of a middle distillate fuel composition, the additive composition comprising:

(b) one or more low temperature performance enhancing agents which are not fumarate vinyl ester copolymers and are selected from: (x) Wax anti-settling additives, (y) middle distillate flow improvers and mixtures thereof; and

(c) a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl and R¹And R²Each is an alkyl group.

According to a fourth aspect of the present invention there is provided a middle distillate fuel composition comprising:

(a) a nitrogen-containing dispersant;

(c) a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl and R¹And R²Each is an alkyl group.

Preferred features of the first, second, third and fourth aspects of the invention will now be described.

The present invention relates to improving the low temperature properties of middle distillate fuel compositions by adding an additive (c) which is a copolymer comprising units of formula (a) and units of formula (B):

wherein R is¹And R²Each is an alkyl group.

The additive (c) may be prepared by copolymerizing a vinyl ester monomer and a fumaric acid monomer and then esterifying the acid residues.

Preferably the additive (c) is prepared by copolymerising a vinyl ester monomer and a dialkyl fumarate monomer.

The additive (C) is preferably a copolymer prepared by reacting a vinyl ester monomer of formula (C) and a dialkyl fumarate monomer of formula (D):

。

each monomer of formula (C) used to prepare copolymer additive (C) may be the same or the copolymer may be prepared from a mixture of two or more different monomers of formula (C).

R is an alkyl group, preferably an unsubstituted alkyl group.

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.

Preferably R is an unsubstituted alkyl group having 1 to 4 carbon atoms.

Most preferably R is methyl and the monomer of formula (C) is vinyl acetate.

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

Preferably all monomers of formula (D) used for preparing the additive (c) are identical.

R¹And R²Each may be the same or different. Preferably R¹And R²The same is true.

R¹And R²Each is an alkyl group. Preferably, each is an unsubstituted alkyl group. R¹And R²And may be straight chain or branched. Preferably R¹And R²Each is a straight chain alkyl group.

Preferably R¹And R²Each being an alkyl group having less than 18 carbon atoms.

Preferably R¹And R²Each of 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 most preferably 14 carbon atoms. Most preferably R¹Is C₁₄H₂₉And R²Is C₁₄H₂₉。

The additive (c) is a copolymer comprising units of formula (a) and units of formula (B). In some embodiments, additive (c) may comprise further additional units not having formula (a) or formula (B). In such embodiments, the copolymer is suitably prepared from a vinyl ester monomer, a fumaric acid-derived monomer (preferably a dialkyl fumarate), and one or more further monomer units. In a preferred embodiment, the one or more further monomer units constitute less than 20 mol%, preferably less than 10 mol%, more preferably less than 5mol%, more preferably less than 1 mol% of all monomer units used for the preparation (c).

In a preferred embodiment, the additive (c) consists essentially of units of formula (a) and units of formula (B). By this we mean that the units of formula (a) and the units of formula (B) together provide at least 80mol%, preferably at least 90 mol%, more preferably at least 95mol%, more preferably at least 99mol%, for example at least 99.5mol% or at least 99.9mol% of all monomer-derived units present in the copolymer.

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 the formula (A) and from 25 to 75 mol% of units of the formula (B); more preferably from 40 to 60 mol% of units of the formula (A) and from 60 to 40 mol% of units of the formula (B).

Preferably the additive (c) is a random copolymer.

Suitably the number average molecular weight of the copolymer additive (c) is 1000-.

In some preferred embodiments, the copolymer additive (c) has a number average molecular weight of 20000 to 25000.

In some particularly preferred embodiments, the copolymer additive (c) has a number average molecular weight of 8000 to 12000.

In a particularly preferred embodiment, the additive (c) is a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl, R¹And R²Each being an alkyl group having less than 18 carbon atoms, preferably 12 to 16 carbon atoms, and the number average molecular weight of the copolymer being 8000-25000. Most 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).

Additive (c) is used to improve the low temperature properties of a middle distillate fuel composition comprising:

(a) a nitrogen-containing dispersant; and

(b) one or more low temperature performance enhancing agents which are not fumarate vinyl ester copolymers and are selected from (x) wax anti-settling additives, (y) middle distillate flow improvers and mixtures thereof.

Any suitable nitrogen-containing detergent may be used as component (a).

Suitable nitrogen-containing detergents for use herein include:

(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 a carboxylic acid-derived acylating agent and an amine;

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

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

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

(vii) polyalkene substituted amines (polyalkenylene substitated amines).

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

(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 a carboxylic acid-derived acylating agent and an amine.

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

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

The nitrogen-containing species may be selected from:

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

(q) a mannich reaction product comprising a tertiary amine group; and

(r) polyalkene-substituted amines having at least one tertiary amine group.

Examples of quaternary ammonium salts and methods of making the same are described in the following patents, which are incorporated herein by reference: US2008/0307698, US2008/0052985, US2008/0113890 and US 2013/031827.

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

Component (q) 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.

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

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

The hydrocarbyl-substituted acylating agent is preferably a mono-or polycarboxylic acid (or reactive equivalent thereof), such as a substituted succinic, phthalic or propionic acid.

Most preferably the acylating agent is a hydrocarbyl substituted succinic acid or anhydride.

The hydrocarbyl substituent in such acylating agents preferably contains at least 8, more preferably at least 12, e.g., 30 or 50 carbon atoms. Which may contain up to about 200 carbon atoms. Preferably the hydrocarbyl substituent of the acylating agent has a number average molecular weight (Mn) of 170-. Mn of 700-.

In some preferred embodiments, the hydrocarbyl-based substituent is poly (isobutylene) known in the art. Thus, in a particularly preferred embodiment, the hydrocarbyl-substituted acylating agent is polyisobutenyl-substituted succinic anhydride.

The preparation of polyisobutenyl substituted succinic anhydrides (PIBSAs) is well documented in the art.

Examples of the nitrogen-or oxygen-containing compound capable of condensing with the acylating agent and further having a tertiary amino group may include, but are not limited to: n, N-dimethylaminopropylamine, N, N-diethylaminopropylamine, N, N-dimethylaminoethylamine, 1- (3-aminopropyl) imidazole, 4- (3-aminopropyl) morpholine, 1- (2-aminoethyl) piperidine, 3-diamino-N-methyldipropylamine 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-tris (hydroxyethyl) amine, N, N, N-tris (hydroxymethyl) amine, N, n, N-tris (aminoethyl) amine, N-dibutylaminopropylamine and N, N '-trimethyl-N' -hydroxyethyl-bisaminoethylether; 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.

Most preferably, the alcohol or amine compound reacted with the acylating agent and having a tertiary amino group is dimethylaminopropylamine or dimethylaminopropanol.

The quaternary ammonium salt additive (i) is formed by reacting a nitrogen-containing species having a tertiary amine group with a quaternizing agent.

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

The quaternising agent is suitably selected from dialkyl sulphates; a carboxylic acid ester; an alkyl halide; a benzyl halide; hydrocarbyl-substituted carbonates; and a hydrocarbyl epoxide in combination with an acid; or mixtures thereof.

Examples of hydrocarbyl epoxides may include styrene oxide, ethylene oxide, propylene oxide, butylene oxide, stilbene oxide, and C2-50 epoxides.

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

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.

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

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 acid-free quaternized nitrogen compounds as disclosed in US 2012/0010112.

Further suitable quaternary ammonium compounds for use in the present invention include those described in applicants' co-pending applications WO2011095819, WO2013/017889, WO2015/011506, WO2015/011507, WO2016/016641 and PCT/GB 2016/052312.

In some embodiments, component (a) comprises the product of a mannich reaction between (ii) an aldehyde, an amine, and an optionally substituted phenol. The mannich reaction product is suitably not a quaternary ammonium salt.

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.

Suitable amines for use in preparing the mannich additives include monoamines and polyamines. One suitable monoamine is butylamine.

The amine used to prepare the mannich additive is preferably a polyamine. This may be selected from any compound comprising two or more amine groups. Preferably, the polyamine is a polyalkylene polyamine, preferably a polyethylene polyamine, especially a polyethylene polyamine having from 1 to 10 ethylene groups and from 2 to 11 amine groups.

Commercially available sources of polyamines typically contain mixtures of isomers and/or oligomers, and products prepared from these commercially available mixtures fall within the scope of the present invention.

Suitably, the polyamine may be selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, propane-1, 2-diamine, 2 (2-amino-ethylamino) ethanol and N ', N' -bis (2-aminoethyl) ethylenediamine (N (CH)₂CH₂NH₂)₃)。

Most preferably, the polyamine comprises tetraethylenepentamine or ethylenediamine.

The optionally substituted phenol component used to prepare the mannich additive may be substituted on the aromatic ring with 0-4 groups (in addition to the phenol OH). For example, it may be a hydrocarbyl-substituted cresol. Most preferably, the phenol component is a monosubstituted phenol. Preferably it is a hydrocarbyl-substituted phenol. Preferred hydrocarbyl substituents are alkyl substituents having from 4 to 28 carbon atoms, especially from 10 to 14, for example 12 carbon atoms. Other preferred hydrocarbyl substituents are polyalkenyl substituents. The number average molecular weight of the polyisobutenyl substituent is 400-2500, e.g., 500-1500.

Suitable mannich reaction products, reaction products of hydrocarbyl-substituted acylating agents with compounds containing at least one tertiary amine group and a primary, secondary or alcohol group, useful as additives herein are described in the applicants patents and applications; WO2009/040582, WO2009/040583, WO2009/040584, WO2009/040585, WO2010/097624, WO2013/017884, WO2013/017886 and WO 2013/017887.

Preferred mannich reaction product additives for use herein are the reaction products of hydrocarbyl-substituted phenols, formaldehyde and polyamines (preferably polyethylene polyamines).

Preferably the Mannich reaction product additive is formed by the reaction of a phenol substituted with an alkyl group having 6 to 30 carbon atoms or a polyisobutenyl group having a number average molecular weight of 500-2000 with formaldehyde and a polyamine, preferably a polyethylene polyamine.

Particularly preferred Mannich reaction products for use herein as the nitrogen-containing detergent (a) are reaction products of dodecylphenol, formaldehyde and ethylenediamine or tetraethylpentamine.

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

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

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

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

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

Particularly preferred PIBSA's are those having a PIB molecular weight (Mn) of 300-.

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

One preferred acylated nitrogen-containing compound for use herein is prepared by reacting a poly (isobutylene) substituted succinic acid-derived acylating agent (e.g., anhydride, acid, ester, etc.) with a mixture of an ethylene polyamine having from 2 to about 9 amino nitrogen atoms, preferably from about 2 to about 8 nitrogen atoms per ethylene polyamine and from about 1 to about 8 ethylene groups, wherein the poly (isobutylene) substituent has a number average molecular weight (Mn) of from 170 to 2800. These acylated nitrogen compounds are suitably formed by reaction of the acylating agent to amino compound in a molar ratio of from 10:1 to 1:10, preferably from 5:1 to 1:5, more preferably from 2:1 to 1:2 and most preferably from 2:1 to 1:1. In a particularly preferred embodiment, the acylated nitrogen compound is formed by reaction of a molar ratio of acylating agent to amino compound of from 1.8:1 to 1:1.2, preferably from 1.6:1 to 1:1.2, more preferably from 1.4:1 to 1:1.1 and most preferably from 1.2:1 to 1:1. Acylated amino compounds of this type and their preparation are well known to the person skilled in the art and are described, for example, in EP0565285 and US 5925151.

In some preferred embodiments, the compositions comprise a detergent of the type formed by the reaction of a polyisobutylene-substituted succinic-derived acylating agent and a polyethylene polyamine. Suitable compounds are described, for example, in WO 2009/040583.

Particularly preferred additives of this type are the reaction products of polyisobutenyl-substituted succinic acids/anhydrides having a PIB molecular weight (Mn) of 500-1300 and polyethylenepolyamines having from 1 to 9 amino groups and from 1 to 8 ethylene groups.

In some embodiments, component (a) comprises the reaction product of (iv) a carboxylic acid-derived acylating agent and hydrazine.

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

Preferably, the hydrocarbyl group of the hydrocarbyl-substituted succinic acid or anhydride comprises C₈-C₃₆Radical, preferably C₈-C₁₈A group. Alternatively, the hydrocarbyl group may be a polyisobutylene group having a number average molecular weight of 200-.

Hydrazine has the formula NH₂-NH₂. Hydrazine may be hydrated or non-hydrated. Hydrazine monohydrate is preferred.

The reaction between hydrocarbyl-substituted succinic acids or anhydrides and hydrazine produces various products, as disclosed in, for example, US 2008/0060259.

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.

Such additives may suitably be of the formula [ R' (COOH)_X]_y'Wherein each R' is independently a hydrocarbon group of 2 to 45 carbon atoms and x is an integer of 1 to 4.

In a preferred embodiment, the carboxylic acid comprises Tall Oil Fatty Acid (TOFA).

Further preferred features of this type of additive are described in EP 1900795.

In some embodiments, component (a) comprises (vi) the reaction product of a hydrocarbyl-substituted dicarboxylic acid or anhydride and an amine compound or salt, the product comprising at least one aminotriazole group.

Further preferred features of this type of additive compound are as defined in US 2009/0282731.

In some embodiments, component (a) comprises (vii) a polyalkene-substituted amine.

The polyalkene-substituted amine may be derived from an olefin polymer and an amine, such as ammonia, a monoamine, a polyamine, or mixtures thereof. They may be prepared by various methods, such as those described and mentioned in US 2008/0113890.

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

The polyalkene-substituted amine may have a number average molecular weight of 500 to 5000, or 500 to 3000, for example 1000 to 1500.

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

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

-the product of a mannich reaction between a hydrocarbyl-substituted phenol, formaldehyde and a polyamine; and

-the reaction product of a hydrocarbyl-substituted succinic acid-derived acylating agent and an amine.

More preferably, component (a) is selected from one or more of the following:

-a quaternary ammonium salt additive formed by the reaction of a quaternizing agent with the reaction product of a polyisobutenyl-substituted succinic anhydride and an amine or alcohol further comprising a tertiary amino group, preferably wherein the quaternizing agent is selected from dialkyl sulfates; a carboxylic acid ester; an alkyl halide; a benzyl halide; hydrocarbyl-substituted carbonates; and a hydrocarbyl epoxide in combination with an acid; or mixtures thereof;

products of a Mannich reaction between a phenol substituted by an alkyl group having from 6 to 30 carbon atoms or a polyisobutenyl group having a number average molecular weight of 500-2000 and formaldehyde and a polyamine selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, propane-1, 2-diamine, 2 (2-amino-ethylamino) ethanol and N ', N' -bis (2-aminoethyl) ethylenediamine (N (CH)₂CH₂NH₂)₃) (ii) a And

-the reaction product of a polyisobutenyl-substituted succinic acid-derived acylating agent and a polyamine.

Most preferably, component (a) is selected from one or more of the following:

-a quaternary ammonium salt additive formed by reacting methyl salicylate or dimethyl oxalate with the reaction product of polyisobutylene-substituted succinic anhydride and dimethylaminopropylamine having a PIB number average molecular weight of 700-1300;

-a mannich reaction product of dodecylphenol, formaldehyde and ethylenediamine or tetraethylpentamine; and

reaction products of polyisobutenyl-substituted succinic acids/anhydrides having a PIB molecular weight (Mn) of 500-1300 and polyethylene polyamines having 1 to 9 amino groups and 1 to 8 ethylene groups.

Component (b) comprises one or more low temperature performance enhancing agents which are not fumarate vinyl ester copolymers and are selected from (x) wax anti-settling additives, (y) middle distillate flow improvers and mixtures thereof.

Preferably, component (b) comprises at least one wax anti-settling additive (x).

Preferably component (b) comprises at least one middle distillate flow improver (y).

More preferably, component (b) comprises at least one wax anti-settling additive (x) and at least one middle distillate flow improver (y).

Preferred wax anti-settling additives (x) are (I) containing a segment-NR³R⁴Wherein R is³Represents a group containing 4 to 44 carbon atoms and R⁴Represents a hydrogen atom or a group R³And (II) a carboxylic acid having from 1 to 4 carboxylic acid groups or a reactive equivalent thereof.

Preferably R³Is a hydrocarbyl group or a polyethoxy or polypropoxy group.

Preferably the group R³Is a hydrocarbyl group. Preferably R³Is a hydrocarbon group, preferably a linear hydrocarbon group.

Preferably, the group R³Containing from 6 to 36 carbon atoms, preferably from 8 to 32, preferably from 10 to 24, preferably from 12 to 22, most preferably from 14 to 20 carbon atoms.

Those skilled in the art will appreciate that commercial sources of alkylamines and dialkylamines may contain mixtures of homologs. Additives derived from these compounds are within the scope of the present invention.

R⁴May be according to R³A group as defined in (1) or hydrogen.

R⁴Preferably according to the formula³The same definitions are given. R³And R⁴Need not be the same. However, R is preferred³And R⁴Are the same.

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

Reactive equivalents of carboxylic acids include anhydrides, spirodilactones, and acid halides.

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

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

Of the formula HNR³R⁴Secondary amines of (4) are a particularly preferred class of compounds (I). Examples of particularly preferred secondary amines include dioctadecyl amine, coco-di amine, dihydrotallow amine and methyl docosyl amine. Amine mixtures are also suitable, such as those derived from natural materials. One preferred amine is para-hydrogenated tallow amine, the alkyl group of which is derived from about 3-5% wt C₁₄、30-32%wt C₁₆And 58-60% wt C₁₈Composed hydrogenated tallow fat (hydrogenated tall fat).

Formula [ + NR³R⁴R⁵R⁶–An]Is a further preferred class of compounds (I). R³And R⁴Is as defined above (but R is⁴Not hydrogen). R⁵And R⁶Independently represents C (1-4) alkyl, preferably propyl, ethyl or most preferably methyl. + NR³R⁴(CH₃)₂Representing the preferred cation. -An represents An anion. The anion may be any suitable species, but is preferably a halide ion, especially chloride. When (I) includes a quaternary amine, the reaction conditions may be adjusted to facilitate the reaction between (I) and (II). Preferably, the reaction conditions are adjusted by introducing an auxiliary base. The auxiliary base is preferably a metal alkoxide or metal hydroxide. Alternatively, the quaternary ammonium salts may be preformed into the corresponding basic salts, such as quaternary ammonium hydroxides or alkoxides.

Mixtures of primary and secondary amines or mixtures of secondary and quaternary amines may be provided as species (I).

Preferred carboxylic acids (II) include carboxylic acids containing two, three or four carboxylic acid groups and their reactive equivalents.

Examples of suitable carboxylic acids and their anhydrides include aminoalkylenepolycarboxylic acids, such as nitrilotriacetic acid, propylenediaminetetraacetic acid, ethylenediaminetetraacetic acid, and carboxylic acids based on a cyclic skeleton, such as pyromellitic acid, cyclohexane-1, 2-dicarboxylic acid, cyclohexene-1, 2-dicarboxylic acid, cyclopentane-1, 2-dicarboxylic acid and naphthalenedicarboxylic acid, 1, 4-dicarboxylic acid and dialkyl spirodilactones. In generalThese acids have about 5 to 13 carbon atoms in the cyclic moiety. Preferred acids for use in the present invention are optionally substituted benzenedicarboxylic acids, such as phthalic acid, isophthalic acid and terephthalic acid, and their anhydrides or acid chlorides. Optional substituents include 1-5 substituents, preferably 1-3 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-CONR³R⁴Wherein R is³And R⁴Independently selected from hydrogen and C (1-4) alkyl. Preferred halogen atoms are fluorine, chlorine and bromine. However, unsubstituted benzene carboxylic acids are preferred. Phthalic acid and its anhydrides are particularly preferred.

Other suitable compounds of formula (II) are alkyl spirodilactones.

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

When compound (II) comprises one or more free carboxylic acid groups, the reaction conditions may be adjusted such that a reaction between compounds (I) and (II) is achieved, for example to form the respective amide or amine salt. The reaction conditions may be appropriately adjusted using methods known to those skilled in the art.

In the case of a preferred reaction between compound (I) and the dicarboxylic acid or reactive equivalent thereof (e.g. anhydride), preferably the molar ratio of compound (I) (or mixture of compound (I), in that case) to the acid or reactive equivalent thereof (or mixed compound (II), in that case) is at least 0.7:1, preferably at least 1:1, preferably at least 1.5: 1. Preferably, it is at most 3:1, preferably at most 2.5: 1. Most preferably, it is in the range of 1.8:1 to 2.2: 1. A molar ratio of (I) to (II) of 2:1 is particularly preferred. In another preferred embodiment, a 1:1 molar ratio is used.

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

Preferably, the reaction between compound (I) and the carboxylic 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.

Thus, in a preferred embodiment, the dicarboxylic acid, anhydride or acid halide (II) is reacted with the secondary amine (I), preferably in a molar ratio of 1:2, such that one mole of the amine forms the amide and one mole forms the ammonium salt.

One particularly preferred additive is the dialkyl ammonium salt of a monoamide of a dialkylamine and phthalic acid, suitably the reaction product of a di (hydrogenated) tallow amine (I) and phthalic acid or anhydride (II) thereof; preferably in a molar ratio of 2: 1.

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

Other preferred wax anti-settling additives are the reaction product of (hydrogenated) tallow amine (I) with edta (ii); a preferred molar ratio is 4:1, wherein four moles of water or two moles of water are removed to form the tetra-amide derivative or the di-amide di-ammonium salt derivative, respectively.

Another preferred additive is the reaction product of an alkyl spirodilactone (II), such as dodecenyl-spirodilactone, with a mono-tallow fatty amine and/or a di-tallow fatty amine (I); preferred are the reaction products of one mole of an alkyl spirodilactone, such as dodecenyl-spirodilactone, with one mole of a mono tallow fatty amine and one mole of a di tallow fatty amine.

Another preferred additive is the reaction product of benzene-1, 2,4, 5-tetracarboxylic acid or its dianhydride (II) with di (hydrogenated tallow) amine (I); preferably in a molar ratio of 1: 4. The reaction product may be referred to as pyromellitic acid tetra-amide but in practice may generally be a mixture of tetra-amide, tri-amide/mono-salt and di-amide/di-salt.

Another suitable wax anti-settling additive is a half amide half ammonium salt of a maleic anhydride alpha olefin copolymer wherein the alpha olefin has from 10 to 36 carbon atoms, preferably from 12 to 24 carbon atoms, for example from 16 to 20 carbon atoms. The amine reacted with the maleic anhydride alpha olefin copolymer is suitably a dialkylamine wherein the alkyl group has from 6 to 30, preferably from 12 to 24, for example 18 carbon atoms. Such additives may be formed, for example, according to the following reaction scheme:

。

one further class of wax anti-settling additives useful herein are alkyl phenol-formaldehyde resins modified by a mannich reaction with an alkyl amine. These compounds are suitably formed by forming an alkylphenol condensate with an aldehyde and then reacting the condensate with an alkylamine and an aldehyde or ketone (preferably an aldehyde) in a mannich reaction. The alkylphenol is suitably mono-substituted with an alkyl group having 1 to 30 carbon atoms; the aldehyde used to prepare the resin preferably has from 1 to 4 carbon atoms. Preferably, the alkylamine preferably comprises one primary amine group and has 12 to 24 carbon atoms. In the Mannich reaction, an aldehyde having 1 to 4 carbon atoms, preferably formaldehyde, is used. These compounds are described in more detail in US 9169452.

Preferred middle distillate flow improvers (y) are copolymers of ethylene and olefinically unsaturated compounds.

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

The ethylenically unsaturated compounds are preferably vinyl esters, acrylic esters, methacrylic esters, alkyl vinyl ethers and/or olefins, and the compounds mentioned may be substituted by hydroxyl groups. One or more comonomers may be present in the polymer.

Vinyl esters are preferably those of the formula (1).

CH₂-CH-OCOR⁷ (1)

Wherein R is⁷Is C1-C30 alkyl. In some embodiments, R⁷May be a C4-C16 alkyl group, for example a C6-C12 alkyl group. In some embodiments, the alkyl group may be substituted with one or more hydroxyl groups. In a preferred embodiment, R⁷Is C1-C10 alkyl, more preferably C1-C4 alkyl, and most preferably C1-C2 alkyl.

Suitable vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl hexanoate, vinyl heptanoate, vinyl octanoate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl laurate, vinyl stearate, and tertiary carbonates (Versatic esters) such as vinyl neononanoate, vinyl neodecanoate, vinyl neoundecanoate. One particularly preferred vinyl ester is vinyl acetate.

In some embodiments, these ethylene copolymers may contain vinyl acetate and at least one further vinyl ester of formula (1) wherein R⁷Is C4-C30 alkyl, preferably C4-C16 alkyl, especially C6-C12 alkyl.

In a preferred embodiment, the compound of formula (1) is vinyl acetate and the middle distillate flow improver (y) comprises a copolymer of ethylene and vinyl acetate. Preferably, the copolymer comprises 76 to 63 wt% ethylene and 24 to 37 wt% vinyl acetate, more preferably 74 to 65 wt% ethylene and 26 to 35 wt% vinyl acetate.

The acrylates are preferably those of formula (2).

CH₂-CR⁸-COOR⁹ (2)

Wherein R is⁸Is hydrogen or methyl and R⁹Is C1-C30 alkyl, preferably C4-C16 alkyl, especially C6-C12 alkyl. Suitable acrylates include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate, hexyl (meth) acrylate, octyl, 2-ethylhexyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, and mixtures of these comonomers. In a further embodiment, the alkanes mentionedThe radicals may be substituted by one or more hydroxyl groups. An example of such an acrylate is hydroxyethyl methacrylate.

The alkyl vinyl ether is preferably a compound of formula (3).

CH₂-CH-OR¹⁰ (3)

Wherein R is¹⁰Are C1-C30-alkyl, preferably C4-C16-alkyl, in particular C6-C12-alkyl. Examples include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether. In a further embodiment, the alkyl groups mentioned may be substituted by one or more hydroxy groups.

The olefin is preferably a monounsaturated hydrocarbon having from 3 to 30 carbon atoms, in particular from 4 to 16 carbon atoms, in particular from 5 to 12 carbon atoms. Suitable olefins include propylene, butene, isobutylene, pentene, hexene, 4-methylpentene, octene, diisobutylene and norbornene and their derivatives such as methylnorbornene and vinylnorbornene. In a further embodiment, the alkyl groups mentioned may be substituted by one or more hydroxy groups.

In some embodiments, the middle distillate flow improver (y) may comprise a terpolymer comprising ethylene, vinyl acetate and further monomers such as longer chain vinyl esters or longer chain olefins.

In addition to ethylene, some particularly preferred terpolymers contain from 1 to 23 mol%, preferably from 3 to 20 mol%, in particular from 8 to 15 mol%, of vinyl acetate and from 0.1 to 12 mol%, in particular from 0.2 to 5mol%, of at least one relatively long-chain and preferably branched vinyl ester, for example vinyl 2-ethylhexanoate, vinyl neononanoate or vinyl neodecanoate, the total comonomer content of the terpolymer preferably being from 8 to 21 mol%, in particular from 12 to 18 mol%. Other preferred copolymers contain, in addition to ethylene and from 8 to 18 mol% of vinyl esters of C2-C12-carboxylic acids, from 0.5 to 30 mol%, preferably from 0.5 to 10 mol%, of olefins, such as propylene, butene, isobutene, hexene, 4-methylpentene, octene, diisobutylene and/or norbornene.

In some embodiments, it is preferred to use a mixture of two or more of the above ethylene copolymers. More preferably, the polymers on which the mixture is based differ in at least one characteristic. For example, they may contain different comonomers, or have different comonomer contents, molecular weights and/or degrees of branching.

Most preferably, the middle distillate flow improver (y) is a copolymer of ethylene and vinyl acetate.

Preferably, the weight ratio of wax anti-settling additive (x) to middle distillate flow improver (y) present in component (b) is from 10:1 to 1:10, preferably from 5:1 to 1:10, more preferably from 2:1 to 1:10, most preferably from 1:1 to 1: 10.

The above proportions are calculated on the active amounts of all wax anti-settling additives (x) and all middle distillate flow improvers (y) present in component (b).

The additive composition of the third aspect comprises component (b) and an additive (c).

The weight ratio of additive (c) to 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.

Preferably, the additive composition of the third aspect comprises a wax anti-settling additive (x), a middle distillate flow improver (y) and a copolymer additive (c).

Preferably, the additive composition of the third aspect comprises (by weight) 10 to 40 parts of a wax anti-settling additive (x); 50 to 88 parts of middle distillate flow improver (y) and 2 to 20 parts of copolymer additive (c), based on the total active weight of (x), (y) and (c).

The additive composition of the third aspect suitably further comprises a diluent or carrier. Suitable diluents and carriers will be known to those skilled in the art and include, for example, solvents, particularly aromatic and aliphatic organic solvents and mixtures thereof.

The additive composition of the third aspect may further contain additional additives to improve handling, such as esters, carboxylic acids and alcohols.

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

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

Suitably component (a) is present in the middle distillate fuel composition in an amount of up to 10000 ppm, preferably up to 1000 ppm, more preferably up to 500 ppm, for example up to 250 ppm or up to 200 ppm.

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

Suitably component (b) is present in the middle distillate fuel composition in an amount of at most 10000 ppm, preferably at most 5000 ppm, more preferably at most 1000 ppm, for example at most 500 ppm, at most 400 ppm or at most 350 ppm.

Suitably, the wax anti-settling additive (x) is present in the middle distillate fuel composition in an amount of at least 0.1 ppm, preferably at least 1ppm, more preferably at least 5ppm, suitably at least 10 ppm.

Suitably, the wax anti-settling additive (x) is present in the middle distillate fuel composition in an amount of at most 10000 ppm, preferably at most 1000 ppm, more preferably at most 500 ppm, for example at most 200ppm or at most 100 ppm.

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

Suitably, the middle distillate flow improver (y) is present in the middle distillate fuel composition in an amount of up to 10000 ppm, preferably up to 1000 ppm, more preferably up to 500 ppm, for example up to 350 ppm or up to 300 ppm.

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

Suitably, additive (c) is present in the middle distillate fuel composition in an amount of at most 10000 ppm, preferably at most 1000 ppm, more preferably at most 500 ppm, suitably at most 200ppm, for example at most 100 ppm or at most 60 ppm.

Each of components (a), (b), (x), (y) and (c) may 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) present in the composition, respectively.

All amounts of additives referred to herein relate to the amount of active present in the composition, and all parts per million (ppm) are by weight, unless otherwise indicated.

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

The base fuel used in the present invention may comprise or consist of a petroleum-based middle distillate fuel oil. Such middle distillate fuel oils typically boil in the range of 110 ℃ to 500 ℃, e.g., 150 ℃ to 400 ℃. The middle distillate fuel oil may comprise atmospheric or vacuum distillates, cracked gas oils, or blends of straight run and refinery streams from conversion units in any proportion, such as thermally and/or catalytically cracked and hydrocracked distillates.

The fuel composition of the invention may comprise or consist of a non-renewable fischer-tropsch fuel such as those described as GTL (gas-liquid) fuels, CTL (coal-liquid) fuels and OTL (oil sands-liquid).

The fuel composition may comprise a first generation biofuel. The first generation biofuels contained esters of, for example, vegetable oils, animal fats, and used cooking fats. Biofuels in this form can be obtained by transesterification of an oil, such as rapeseed oil, soybean oil, safflower oil, palm oil, corn oil, peanut oil, cottonseed oil, tallow (tallow), coconut oil, physic nut oil (Jatropha), sunflower oil, used cooking oil, hydrogenated vegetable oil or any mixture thereof, with an alcohol, typically a monohydric alcohol, in the presence of a catalyst.

This first generation biofuel may be referred to as Fatty Acid Alkyl Esters (FAAE), preferably Fatty Acid Methyl Esters (FAME).

The fuel composition may comprise a second generation biofuel. Second generation biofuels are derived from renewable resources such as vegetable oils and animal fats and are processed, typically in refineries, typically using hydroprocessing such as the H-Bio process developed by Petrobras. Second generation biofuels can be similar in nature and quality to petroleum-based fuel oil streams, such as Renewable fuels manufactured from vegetable oils, animal fats, and the like and sold by ConocoPhillips as Renewable Diesel and by Neste as NExBTL.

The fuel composition of the present invention may comprise a third generation biofuel. Third generation biofuels utilize gasification and fischer-tropsch technologies, including those described as BTL (biomass-to-liquid) fuels. Third generation biofuels do not differ much from some second generation biofuels, but aim to utilize the whole plant (biomass) and thus broaden the feedstock base.

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

In some embodiments, the fuel composition of the present invention may be a blended fuel comprising a biofuel and a second fuel. In such blends, the biofuel may be present in an amount of from 0.1% to 99% (volume/volume), preferably from 0.1 to 25%. In such blends, the biofuel component may comprise a mixture of a first generation biofuel and a second generation biofuel. The first generation biofuel, preferably FAAE, especially FAME, suitably provides 0.1-25% (v/v), preferably 0.1-20%, more preferably 0.1-12%, e.g. 0.1-10% of the fuel composition. The second fuel may be a petroleum-based fuel oil, particularly a middle distillate fuel oil, including non-renewable fischer-tropsch fuels.

All of these fuels may be used in embodiments of the present invention.

In some embodiments, the fuel composition of the present invention may comprise petroleum-based middle distillate fuel oil and optionally 0.1% to 25% (v/v) biofuel, wherein the fuel composition optionally comprises 0.1% to 12% (v/v) FAAE.

The fuel compositions of the present invention may contain a relatively high sulfur content, for example greater than 0.05 wt%, such as 0.1%, or 0.2%, 0.5% or higher.

However, in a preferred embodiment, the fuel has a sulphur content of at most 0.05 wt.%, more preferably at most 0.035 wt.%, especially at most 0.015 wt.%. Fuels with even lower sulfur levels are also suitable, such as fuels with less than 50ppm sulfur, preferably less than 20 ppm, e.g., 10ppm or less, by weight.

The fuel composition of the present invention can be used as a sport fuel (fuel for a sport) for motor vehicles, ships and boats; as a burner fuel in domestic heating and power generation and as a fuel in multi-use stationary engines.

The fuel composition may comprise one or more further additives, such as those typically found in the fuels used in the present invention. These additives include, for example, antioxidants, other dispersants and/or detergents, cetane improvers, dehazers, stabilizers, demulsifiers, defoamers, corrosion inhibitors, lubricity improvers, dyes, markers, combustion improvers and odor masking agents, and other additives useful for achieving low temperature performance improvements.

In a preferred embodiment of the invention, component (a) is selected from one or more of the following:

-the reaction product of a hydrocarbyl-substituted succinic acid-derived acylating agent and an amine;

component (b) comprises:

-copolymers of ethylene and vinyl acetate; and

- (I) a reaction product of a compound containing the segment-NR 3R4, wherein R3 represents a group containing 4 to 44 carbon atoms and R4 represents a hydrogen atom or a group R3, and (II) a carboxylic acid having 1 to 4 carboxylic acid groups or an anhydride or acid halide thereof; and

additive (c) comprises a copolymer of vinyl acetate and a monomer of formula (D):

wherein R is¹And R²Each being an alkyl group having less than 18 carbons.

In the present invention, the copolymer additive (c) improves the low temperature properties of the middle distillate fuel composition.

Preferably, the additive reduces the value of Δ CP as measured by the short deposition test.

Many short deposition tests are known. However, all of these short deposit tests seek to minimize the difference (Δ CP) between the Cloud Point (CP) of the fuel bottoms fraction and another fraction of the fuel to which the additive is added or the base fuel.

Suitably, the copolymer additive (c) provides a Δ CP of less than 5 ℃, preferably less than 3 ℃, more preferably less than 2 ℃ in the short deposition test. Suitably, the short deposition test protocol described in example 2, procedure a, provides a Δ CP of less than 3 ℃, preferably less than 2 ℃.

Preferably, the polymer additive (c) improves the low temperature properties of the middle distillate fuel composition by affecting the antagonistic interaction between component (a) and component (b).

According to a fifth aspect of the present invention there is provided the use of an additive (c) to improve the antagonistic interaction between (a) a nitrogen-containing dispersant and (B) one or more low temperature performance enhancing agents in a middle distillate fuel composition, the additive (c) being a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl and R¹And R²Each is an alkyl group;wherein the low temperature performance enhancing agent is not a vinyl ester copolymer and is selected from the group consisting of (x) wax anti-settling additives, (y) middle distillate flow improvers and mixtures thereof.

By improving antagonistic interactions in a middle distillate fuel composition we mean preventing and/or inhibiting the antagonistic effect and/or providing a further effect which counteracts the antagonistic effect. Thus, the addition of the copolymer additive (c) may prevent or reduce the occurrence of negative interactions between component (a) and component (b) or it may provide a further effect, which means that the antagonistic interactions between component (a) and component (b) do not have such a negative effect on the low temperature performance of the fuel.

Suitably, the addition of copolymer additive (c) improves the low temperature performance of the middle distillate fuel composition as measured by the short deposition 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 Δ CP value. Suitably, a Δ CP of less than 3 ℃, preferably less than 2 ℃, is provided according to the short deposition test protocol described in example 2, procedure a.

Accordingly, the present invention may further provide the use of a copolymer additive (c) as defined herein for improving the performance in a short deposit test of a middle distillate fuel composition comprising:

(a) a nitrogen-containing dispersant; and

(b) one or more low temperature performance enhancing agents selected from the group consisting of (x) wax anti-settling additives, (y) middle distillate flow improvers, and mixtures thereof.

Advantageously, the copolymer additive (c) is highly effective in improving the antagonistic interaction between the component (a) and the component (b) even at a low processing rate. Thus, the present invention may provide the use of less than 120 ppm of a copolymer additive (c) to improve the antagonistic interaction between component (a) and component (b) in a middle distillate fuel composition.

Suitably, the present invention may provide the use of less than 100 ppm of an additive (c) to improve the antagonistic interaction between component (a) and component (b) in a middle distillate fuel composition.

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

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

Examples

In the examples, the following additives were metered into middle distillate fuels:

an A-ethylene vinyl acetate copolymer comprising 30-32% (wt%) vinyl acetate units and having a number average MW of about 4-5000, provided in an aromatic solvent.

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

A copolymer of vinyl acetate and diesters of fumaric and tetradecanol at a C-1:1 molar ratio, having a number average MW of about 10,000, provided in an aromatic solvent.

D-A reaction product of polyisobutenyl succinic anhydride having a PIB number average molecular weight of 750 and a mixture of polyethylene polyamines corresponding to tetraethylene pentamine to form polyisobutylene succinimide, provided in an aromatic solvent.

A Mannich reaction product of E-dodecylphenol, formaldehyde and ethylenediamine, provided in an aromatic solvent.

F-A reaction product of polyisobutylene-substituted succinic anhydride having a PIB number average molecular weight of 1000 reacted with dimethylaminopropylamine to form an imide and then quaternized by reaction with methyl salicylate, provided in an aromatic solvent.

A G-ethylene vinyl acetate copolymer comprising 28 wt% vinyl acetate units and having a number average MW of about 3 to 4000, provided in an aromatic solvent.

A copolymer of vinyl acetate with diesters of fumaric acid and tetradecanol in an H-1:1 molar ratio, having a number average MW of about 21,000, provided in an aromatic solvent.

I (comparative) -copolymers of alpha olefins and behenyl maleate, provided in an aromatic solvent.

The C16/18 diester of a J (comparative) -C24/26 alpha olefin maleic anhydride copolymer, provided in an aromatic solvent.

C16/C18 alkylimide of K (comparative) -C14/C16 alpha olefin maleic anhydride copolymer, provided in an aromatic solvent.

A copolymer of vinyl acetate and a diester of fumaric acid and dodecanol at an L-1:1 molar ratio, having a number average MW of about 30,000, provided in an aromatic solvent.

A copolymer of vinyl acetate with a diester of fumaric acid and dodecanol at a molar ratio of M-1:1, having a number average MW of about 33,000, provided in an aromatic solvent.

Example 1

Fuel compositions were prepared by adding the amounts specified in tables 4 and 5 to the fuel compositions described below.

Compositions 1-10 were prepared in fuel 1, which fuel 1 was a middle distillate fuel composition having a specification corresponding to EN 590 and having the properties shown in table 1.

Compositions 11 and 12 were prepared in fuel 2, which fuel 2 was a middle distillate fuel composition having a specification corresponding to EN 590 and having the properties shown in table 2.

Compositions 13-16 were prepared in fuel 3, which was a middle distillate fuel composition having specifications corresponding to EN 590 and having the properties shown in table 3, blended with 7% by volume of fatty acid methyl ester to give a fuel having a cloud point of-9 ℃ and a CFPP of-9 ℃.

TABLE 1 Properties of Fuel 1

。

TABLE 2 Properties of Fuel 2

。

TABLE 3 Properties of Fuel 3

。

TABLE 4

。

TABLE 5

。

Example 2

Fuel compositions 1-17 were tested in the short deposit test according to process a and/or process B. The results are shown in Table 6.

Process A

450g of base fuel was mixed with appropriate amounts of additives and the cloud point of the treated fuel was determined. 500ml of the treated fuel was transferred to a 500ml graduated cylinder and cooled to the test temperature in a climatic chamber or cooling bath and then held at that temperature for 16 hours. After this 16 hour period, the upper 80% and lower 20% of the fuel were separated and heated to redissolve the precipitated wax. The cloud points of the two fractions were determined. The Δ CP is recorded as the difference between the cloud point of the upper 80% and the cloud point of the lower 20% portion of the fuel.

Process B

150g of base fuel was mixed with the appropriate amount of additives and stored at 40 ℃ for 1 hour. Transfer 100ml into a 100ml graduated cylinder. The cloud point of the treated fuel was determined. The samples were cooled in a cooling bath/climatic chamber to the test temperature and then held at that temperature for 16 hours. After this 16 hour period, the appearance of the fuel and the amount of deposits were recorded. The upper 50% and lower 50% of the fuel were separated and the bottom 50% was stored at 40 ℃ for 1 hour and the cloud point was determined. Δ CP is recorded as the difference between the cloud point of the lower 50% portion of the fuel and the original cloud point of the pre-cooled fuel.

Claims

1. A method of improving the low temperature performance of a middle distillate fuel composition comprising:

(a) a nitrogen-containing dispersant; and

(b) one or more low temperature performance enhancing agents which are not fumarate vinyl ester copolymers and are selected from: (x) Wax anti-settling additives, (y) middle distillate flow improvers and mixtures thereof;

wherein R is alkyl and R¹And R²Each is an alkyl group.

2. Use of a copolymer (c) comprising units of formula (a) and units of formula (B) to improve the low temperature properties of a middle distillate fuel composition:

wherein R is alkyl and R¹And R²Each is an alkyl group;

the middle distillate fuel composition comprises:

(a) a nitrogen-containing dispersant; and

3. An additive composition for improving the low temperature properties of a middle distillate fuel composition, the additive composition comprising:

(c) a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl and R¹And R²Each is an alkyl group.

4. A middle distillate fuel composition comprising:

(a) a nitrogen-containing dispersant;

(c) a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl and R¹And R²Each is an alkyl group.

5. The method, use or composition of any preceding claim, wherein additive (c) is prepared by copolymerizing a vinyl ester monomer and a dialkyl fumarate monomer.

6. The method, use or composition of any one of the preceding claims, wherein R is methyl.

7. The method, use or composition of any of the preceding claims, wherein R¹And R²Each being an alkyl group having less than 18 carbon atoms.

8. A method, use or composition according to any preceding claim, wherein component (a) is selected from

(i) A quaternary ammonium salt additive;

(vii) polyalkene-substituted amines.

9. A method, use or composition according to any preceding claim, wherein component (a) is selected from

(i) A quaternary ammonium salt additive;

10. A method, use or composition according to any preceding claim, wherein component (a) is selected from one or more of the following

reaction products of polyisobutenyl-substituted succinic acids/anhydrides having a PIB molecular weight (Mn) of 500-1300 with polyethylene polyamines having 1 to 9 amino groups and 1 to 8 ethylene groups.

11. A method, use or composition according to any preceding claim, wherein component (b) comprises at least one wax anti-settling additive (x) and at least one middle distillate flow improver (y).

12. The method, use or composition of any preceding claim, wherein component (b) comprises a wax anti-settling additive (x) which is (I) a wax comprising segment-NR³R⁴Wherein R is³Represents a group containing 4 to 44 carbon atoms and R⁴Represents a hydrogen atom or a group R³And (II) a carboxylic acid having from 1 to 4 carboxylic acid groups or a reactive equivalent thereof.

13. A method, use or composition according to any preceding claim, wherein component (b) comprises a wax anti-settling additive (x) which is the reaction product of di (hydrogenated) tallow fatty amine (I) and phthalic acid or anhydride (II) thereof.

14. A process, use or composition according to any preceding claim, wherein component (b) comprises a middle distillate flow improver (y) which is a copolymer of ethylene and an ethylenically unsaturated compound.

15. A process, use or composition according to any preceding claim, wherein component (b) comprises a middle distillate flow improver (y) which contains from 1 to 23 mol% of an ethylenically unsaturated compound as comonomer in addition to ethylene.

16. Use of an additive (c) to improve antagonistic interactions between (a) a nitrogen-containing dispersant and (B) one or more low temperature performance enhancing agents in a middle distillate fuel composition, said additive (c) being a copolymer comprising units of formula (a) and units of formula (B):

wherein R is alkyl and R¹And R²Each is an alkyl group; the low temperature performance enhancer is not a fumarate vinyl ester copolymer and is selected from the group consisting of: (x) Wax anti-settling additives, (y) middle distillate flow improvers, and mixtures thereof.