Improvements in additive compositions and fuel oils

Abstract

The present invention relates to a fuel oil composition comprising an ester of an alkyl neo-monocarboxylic acid having a total number of 5 to 30 carbon atoms and an aliphatic acyclic (C2 to C18) alkanol having a total number of 2 to 18 carbon atoms and a total number of 2 to 8 hydroxyl groups wherein the aliphatic acyclic (C2 to C18) alkanol comprises one or more alkyl chains, and each of the one or more alkyl chains may optionally be intercalated by one or more oxygen atoms, to related fuel additive compositions and to the use of fuel additives.

Description

Field of the Invention

[0001] The present invention relates to additives and / or additive combinations, and to low sulfur content fuel oil compositions, such as middle distillate fuel oils, such as diesel fuel, kerosene and jet fuels, and biofuels, especially diesel fuel, comprising said additives and / or additive combinations, having improved properties.

[0002] Suitably, although not limited thereto, the present invention relates to an additive and / or additive composition for a low-sulfur fuel oil to improve the lubricity and / or electrical conductivity of the low-sulfur fuel oil. Suitably, the present invention further provides a low-sulfur fuel oil composition comprising the additive / additive composition, the fuel oil composition may exhibit improved lubricity and / or reduced engine wear and / or improved electrical conductivity. Therefore, the present invention provides the use of an additive and / or additive composition for improving the lubricity and / or electrical conductivity of a low-sulfur fuel oil. Further, the present invention provides an additive and / or additive composition having improved low-temperature properties (e.g., at -5°C or below -5°C), such as an improved reduced low-temperature viscosity, which promotes ease of use, operability and reduced transportation costs when the additive is used in cold climates. Suitably, although not limited thereto, the low-sulfur fuel oil is a middle distillate fuel oil, preferably a diesel fuel. Background of the Invention

[0004] In the early 1990s, concerns about environmental pollution led to legislation requiring fuel producers to produce fuel oils with lower sulfur content. The sulfur content of fuel oils such as diesel fuel, heating oil and kerosene has been continuously reduced to lower and lower levels, and in Europe, the maximum sulfur content specified by standard EN590 is now 0.001% by weight.

[0005] One result of the refining process for reducing the sulfur and aromatic content of diesel fuel is that the electrical conductivity of the fuel is reduced. Due to the possibility of static charge accumulation and discharge, the insulating properties of low sulfur fuel oil represent a potential danger to refiners, distributors and consumers. Static charge will appear in the pumping of fuel oil, especially in the filtering process, and this charge accumulation constitutes a significant risk as the release of sparks in a highly flammable environment. These risks are minimized by the appropriate grounding of fuel lines and tanks and the use of antistatic additives in combination during fuel processing and operation. These antistatic additives do not prevent the accumulation of static charge, but enhance their release to grounded fuel lines and containers, thereby controlling the danger of sparks. Many such additives are commonly used and can be purchased. One of the most commonly used antistatic additives is a two-component mixture of polysulfone and polymerized polyamine reaction products as disclosed in, for example, U.S. Patent 3,917,466. Although effective, such antistatic additives (such as STADIS) are relatively expensive.

[0006] A further consequence of the refining process used to reduce the sulfur and aromatic content of diesel fuel is that the ability of the fuel oil to lubricate the engine, such as the engine injection system, is reduced, so that, for example, the fuel injection pump of the engine may fail relatively early in the life of the engine. Failure may occur in the fuel injection system, such as high-pressure rotary distributors, in-line pumps and injectors. Future engine developments designed to further reduce emissions (which will have stricter lubricity requirements than current engines) may exacerbate the problem of poor lubricity in low-sulfur diesel fuel oils. For example, the emergence of high-pressure unit injectors is expected to increase the requirements for fuel oil lubricity. Similarly, poor lubricity can lead to wear problems in other mechanical devices that rely on the natural lubricity of the fuel oil for lubrication.

[0007] Lubricity additives for fuel oils have been described in the art. For example, WO 94 / 17160 describes an additive comprising an ester of a carboxylic acid and an alcohol, wherein the acid has 2 to 50 carbon atoms and the alcohol has one or more carbon atoms. For example, glycerol monooleate is specifically disclosed.

[0008] US-A-3,287,273 describes lubricity additives which are reaction products of dicarboxylic acids and oil-soluble diols. The acids are usually mainly dimers of unsaturated fatty acids such as linoleic acid or oleic acid, although small proportions of monomers may also be present. Only alkanediols or oxaalkanediols are specifically suggested as diol reactants.

[0009] However, the use of prior art lubricity additives in fuel oils, especially in low sulfur content fuel oils, may bring other technical problems. For example, the viscosity of prior art lubricity additives may increase significantly with a corresponding decrease in temperature below 20°C. Suitably, under field conditions, fuel oils are usually subjected to different temperature cycles, for example in cold climates, fuel oils may be stored at low ambient temperatures, for example at -5°C and lower. At such low ambient temperatures, known lubricity additives are usually highly viscous, which makes it difficult to handle (e.g. pump the additives), transport, store and treat the fuel oil with additives, especially neat additives.

[0010] A partial solution to the problem of high viscosity of lubricity additives at low ambient temperatures is to supply the lubricity additives in the form of a dilute suspension and / or solution for metering into the fuel oil. Suitably, the suspension and / or solution may contain significantly less than 50% by weight of the lubricity additive on an active ingredient basis, the balance being an inert organic solvent. However, this approach significantly increases the costs associated with the transportation, supply and storage of the lubricity additive, and requires higher top treat rates of the lubricity additive composition to the fuel oil to obtain the desired performance attributes.

[0011] In addition, it has been found that known lubricity additives may inhibit antistatic additives from dissipating static charge from fuel oil and / or reduce the conductivity of fuel oil containing such antistatic additives. Suitably, it has been found that when antistatic agents are used in combination with known lubricity additives, the ability / effectiveness of the antistatic additives to dissipate static discharge from the fuel oil may deteriorate over time. Suitably, the conductivity of a fuel oil comprising a combination of a known lubricity additive and an antistatic additive may decrease significantly over time, possibly to a limit below the required minimum specification limit. Suitably, these problems are more pronounced in low sulfur content fuel oils, because low sulfur content fuel oils generally have lower inherent conductivity than corresponding higher sulfur content counterparts.

[0012] Suitably, the use of lubricity additives in combination with antistatic agents in low sulfur content fuel oils may present various problems, such as: undesirable accumulation of static charge and / or reduction in conductivity of the treated fuel oil, especially over long periods of time (e.g. during storage of the treated fuel oil); reduced effectiveness / ability of the antistatic agent to dissipate static charge, especially over long periods of time; and / or providing a treated fuel oil that not only initially meets the required conductivity specification but also remains within such specification limits over long periods of time (e.g. during and after 28 days, e.g. during storage). A proposed solution to these problems is to over-treat the fuel oil with an initial excess of a relatively more expensive antistatic additive to provide a conductivity well in excess of the minimum specification limit (e.g., the ASTM D975 standard specification for diesel fuel requires a minimum conductivity of 25 pSm at the point of delivery). -1 ) in order to seek to mitigate the inevitable decrease in conductivity of the treated fuel oil over time. However, such a proposal is uneconomical, it may not be possible to provide a treated fuel oil with a predictable conductivity at a specific point in time, and it may not guarantee the provision of a treated fuel oil, particularly a treated low sulphur content fuel oil, with the required minimum conductivity specification at a specific point in time (e.g. after a period of 28 days, e.g. due to storage).

[0013] The present invention seeks to solve one or more of the described technical problems associated with low sulphur content fuel oils.

[0014] Suitably, the present invention seeks to improve the inherently reduced lubricity properties of low sulphur fuel oils by providing an additive and / or additive combination for use with low sulphur fuel oils to enhance the lubricity properties of the low sulphur fuel oils.

[0015] Suitably, the present invention is to provide an additive for low sulphur content fuel oils, wherein the additive has a relatively low viscosity at a temperature below 20°C, suitably at 10°C or below 10°C, suitably at 5°C or below 5°C, suitably at 0°C or below 0°C, suitably at -5°C or below -5°C, particularly when compared to known additives, to facilitate ease of use, handleability (e.g. pumping the additive), transport, storage and handling of the fuel oil with the additive, particularly with the neat additive, at such temperatures. Suitably, the relatively reduced viscosity of the additive may also allow for the provision and use of a concentrated additive composition comprising a relatively high concentration of the additive active ingredient (e.g. greater than or equal to 80% by mass of the additive on an active ingredient basis) and generally a reduced amount of an inert diluent.

[0016] Suitably, the present invention is to provide an additive and / or additive composition for low sulphur content fuel oil, wherein the additive and / or additive composition when used in combination with an antistatic additive is capable of providing a conductivity meeting at least the required minimum conductivity specification, e.g. at least 25 pSm -1 The invention relates to a low sulfur fuel oil composition having an electrical conductivity of at least 100% (relative to the minimum electrical conductivity required by the ASTM D975 standard specification for diesel fuel at the point of delivery), in particular after a long period of time (e.g., after 28 days) after the low sulfur fuel oil is treated with the additive and / or the additive composition.

[0017] Suitably, the present invention is to provide an additive and / or additive composition for low sulphur fuel oil, wherein the additive and / or additive composition when used in combination with an antistatic additive is capable of providing a low sulphur fuel oil composition having a substantially constant conductivity over a long period of time, for example 28 days, after treatment of the low sulphur fuel oil with the additive and / or additive composition in combination with the antistatic additive.

[0018] Suitably, the present invention is to provide an additive and / or additive composition for use in low sulphur content fuels, wherein the additive and / or additive composition, when used in combination with an anti-static additive, does not significantly reduce the effectiveness / ability of the anti-static additive to release static charge from the fuel oil when measured over an extended period of time (e.g. a period of 28 days).

[0019] Suitably, the present invention is to provide an additive and / or additive composition for use in combination with an antistatic additive for use in low sulphur content fuel oils to enhance the lubricity properties of the fuel oil and to provide a fuel oil composition having an electrical conductivity meeting at least the required minimum electrical conductivity specification (e.g. required by the ASTM D975 standard specification for diesel fuel at the point of delivery), particularly over a long period of time (e.g. a period of 28 days) after treatment of the low sulphur content fuel oil with said additive and / or additive composition.

[0020] Suitably, the present invention is to provide an additive and / or additive composition for use in combination with an antistatic additive for low sulphur content fuel oils to enhance the lubricity of the fuel oil and to provide a fuel oil composition having a substantially constant conductivity over a long period of time (e.g. a period of 28 days). SUMMARY OF THE INVENTION

[0022] Therefore, according to a first aspect, the present invention provides a fuel oil composition comprising a major amount of a middle distillate fuel oil having a sulfur content of 0.2 wt% or less and a minor amount of a fuel oil additive (A), the fuel oil additive (A) comprising:

[0023] Alkyl neo-monocarboxylic acids having a total of 5 to 30 carbon atoms, as defined and identified herein, and aliphatic acyclic (C2 to C4) having a total of 2 to 18 carbon atoms and a total of 2 to 8 hydroxyl groups, as defined and identified herein. 18 ) ester of an alkanol, wherein the aliphatic acyclic (C2 to C 18 ) The alkanol comprises one or more alkyl chains, and each of the one or more alkyl chains may be optionally interrupted by one or more oxygen atoms.

[0024] Suitably, the fuel oil additive (A) may be present in the fuel oil composition in an amount of greater than or equal to 1, suitably greater than or equal to 2, suitably greater than or equal to 3, suitably greater than or equal to 4, suitably greater than or equal to 5, suitably greater than or equal to 10, suitably greater than or equal to 50 ppm by mass, on an active ingredient basis, based on the total mass of the fuel oil composition.

[0025] Suitably, the fuel oil additive (A) may be present in the fuel oil composition in an amount of less than or equal to 1000, suitably less than or equal to 750, suitably less than or equal to 500, suitably less than or equal to 400 ppm by mass, on an active ingredient basis, based on the total mass of the fuel oil composition.

[0026] In one embodiment, the fuel oil composition of the first aspect of the invention further comprises an antistatic additive (B) as defined and identified herein present in an effective minor amount. Suitably, the antistatic additive (B) promotes static discharge from the fuel oil composition. Suitably, the antistatic additive (B), when present, may comprise a two-component mixture of a polysulfone and a polymeric polyamine reaction product as defined and identified herein.

[0027] Suitably, the antistatic additive (B), when present, may be present in the fuel oil composition in an amount greater than or equal to 0.1, suitably greater than or equal to 0.2, suitably greater than or equal to 0.3, suitably greater than or equal to 0.4, suitably greater than or equal to 0.5 ppm by mass on an active ingredient basis, based on the total mass of the fuel oil composition.

[0028] Suitably, the antistatic additive (B), when present, may be present in the fuel oil composition in an amount of less than or equal to 10, suitably less than or equal to 7.5, suitably less than or equal to 5, suitably less than or equal to 4 ppm by mass on an active ingredient basis, based on the total mass of the fuel oil composition.

[0029] Suitably, it has been found that the fuel oil additive (A) when used as an additive in a middle distillate fuel oil having a sulphur content of 0.2 wt% or less can improve the lubricity performance of the middle distillate fuel oil. Suitably, the improvement in lubricity performance can be demonstrated by a reduction in wear of components of the fuel supply system of the engine during operation of the engine. Suitably, the fuel oil additive (A) can be referred to as a lubricity additive and the additive composition comprising the fuel oil additive (A) can be referred to as a lubricity additive composition.

[0030] Thus, according to a second aspect, the present invention provides the use of a fuel oil additive (A) as defined and identified in the first aspect as an additive in an effective minor amount in a middle distillate fuel oil having a sulphur content of less than or equal to 0.2 wt. %, based on the total weight of the middle distillate fuel oil, for enhancing the lubricity properties of the fuel oil (i.e. compared to a middle distillate fuel which does not include the fuel oil additive (A)).

[0031] Therefore, according to a third aspect, the present invention provides a method for enhancing the lubricity properties of a middle distillate fuel oil having a sulfur content of less than or equal to 0.2% by weight, based on the total weight of the middle distillate fuel oil, which comprises adding to the fuel oil an effective minor amount of the fuel oil additive (A) defined and identified in the first aspect to enhance the lubricity properties.

[0032] Therefore, according to a fourth aspect, the present invention provides the use of the fuel oil additive (A) as defined and identified in the first aspect as an additive in an effective minor amount in a middle distillate fuel oil having a sulfur content of less than or equal to 0.2% by weight, based on the total weight of the middle distillate fuel oil, for reducing the wear rate in a fuel supply system of a combustion device using said middle distillate fuel oil (i.e. compared to a middle distillate fuel not comprising the fuel oil additive (A)).

[0033] Therefore, according to a fifth aspect, the present invention provides a method for reducing the wear rate in a fuel supply system of a combustion device using a middle distillate fuel oil having a sulfur content of less than or equal to 0.2% by weight, based on the total weight of the middle distillate fuel oil, which comprises adding to the fuel oil a minor proportion of the fuel oil additive (A) defined and identified in the first aspect of the present invention in an effective minor amount for reducing the wear rate.

[0034] Suitably, the use of the fourth aspect and / or the method of the fifth aspect further comprises operating the combustion device. Suitably, the combustion device comprises a spark ignition or compression ignition internal combustion engine, suitably a compression ignition internal combustion engine.

[0035] Suitably, it has been found that the fuel oil additive (A) can be used as an additive in combination with an antistatic additive (B) in a middle distillate fuel oil having a sulphur content of 0.2 wt% or less, to improve the conductivity of said middle distillate fuel oil.

[0036] Thus, according to a sixth aspect, the present invention provides the use of a fuel oil additive (A) as defined and identified in the first aspect and an antistatic additive (B) as defined and identified herein as an additive combination in an effective minor amount in a middle distillate fuel oil having a sulfur content of less than or equal to 0.2% by weight, based on the total weight of the middle distillate fuel oil, for increasing the conductivity of the middle distillate fuel oil.

[0037] Thus, according to a seventh aspect, the present invention provides a method for increasing the conductivity of a middle distillate fuel oil having a sulfur content less than or equal to 0.2% by weight, comprising adding to said fuel oil an effective minor amount of an additive combination to increase the conductivity, wherein said additive combination comprises a fuel oil additive (A) as defined and identified in the first aspect and an antistatic additive (B) as defined and identified herein.

[0038] Suitably, the fuel oil composition comprising the combination of the fuel oil additive (A) and the antistatic additive (B) as defined and identified herein may have a pSm greater than or equal to 25, suitably greater than or equal to 30, suitably greater than or equal to 35, suitably greater than or equal to 40, suitably greater than or equal to 45, suitably greater than or equal to 50 pSm -1 The conductivity of fuel oil is measured routinely and methods for making the measurements are known to those skilled in the art. Commercial devices such as Emcee TM A digital conductivity meter (Model 1152) is available. This device can measure conductivity from 0 to 2000 pSm -1 In the range of 1pSm -1 Measure the conductivity of liquid samples with high accuracy.

[0039] Suitably, it has been found that when the fuel oil additive (A) is used as an additive in combination with an antistatic additive (B) in a middle distillate fuel oil having a sulphur content of 0.2 wt% or less to improve the conductivity of said middle distillate fuel oil, the conductivity improvement of said middle distillate fuel can be maintained at a substantially constant level over a long period of time, for example over a period of 28 days. Suitably, this unexpected technical effect is typically apparent after the fuel oil composition has equilibrated, for example 1 day after the combination of additives (A) and (B) has been added to the fuel oil. Suitably, this enables the provision of a fuel oil composition which not only meets the required conductivity specification but also has a determinable conductivity at a future point in time, without the need to initially over-dosing a large excess of a relatively expensive antistatic additive (B) into the fuel oil.

[0040] Thus, according to an eighth aspect, the present invention provides the use of a fuel oil additive (A) as defined and identified in the first aspect and an antistatic additive (B) as defined and identified herein as an additive combination in an effective minor amount in a middle distillate fuel oil having a sulphur content less than or equal to 0.2 wt. %, based on the total weight of the middle distillate fuel oil, for increasing the electrical conductivity of the middle distillate fuel oil and maintaining the electrical conductivity of the middle distillate fuel oil at a substantially constant level over a long period of time, such as over a period of 28 days.

[0041] Suitably, "maintaining the conductivity of the middle distillate fuel oil at a substantially constant level over a prolonged period of time" means that after a period of 28 days after adding the combination of additives (A) and (B) to the fuel oil, the conductivity of the fuel oil measured as described herein is at least 70%, suitably at least 75%, suitably at least 80%, suitably at least 85%, suitably at least 90%, suitably at least 95% of the conductivity of the fuel oil measured after a period of 1 day after adding the combination of additives (A) and (B) to the fuel oil.

[0042] Thus, according to a ninth aspect, the present invention provides a method for increasing the conductivity of a middle distillate fuel oil having a sulfur content of less than or equal to 0.2 wt. % and maintaining the conductivity of said middle distillate fuel oil at a substantially constant level over a long period of time (e.g. over 28 days), which comprises adding to said fuel oil an effective minor amount of an additive combination to increase the conductivity, wherein said additive combination comprises a fuel oil additive (A) as defined and identified in the first aspect and an antistatic additive (B) as defined and identified herein.

[0043] Suitably, it has been found that the fuel oil additive (A) can be used as an additive in combination with the antistatic additive (B) in a middle distillate fuel oil having a sulfur content of 0.2 wt% or less to enhance the lubricity of the middle distillate fuel oil. Suitably, the uses of the sixth and eighth aspects and the methods of the seventh and ninth aspects can each independently further comprise using a combination of additives (A) and (B) to improve the lubricity of the middle distillate fuel oil.

[0044] Suitably, the combined use of the fuel oil additive (A) and the antistatic additive (B) may enable the formulation of a low sulphur content fuel oil composition having a required lubricity specification, a required conductivity specification, increased conductivity and / or a substantially constant conductivity level over a long period of time (e.g. at least 28 days).

[0045] Suitably, it has been found that the fuel oil additive (A) may have a relatively low viscosity at a temperature below 20°C, suitably at 10°C or below, suitably at 5°C or below, suitably at 0°C or below, suitably at -5°C or below, particularly when compared to known additives. Suitably, the relatively low viscosity of the additive (A) may facilitate ease of use, handleability (e.g. pumping the additive), transport, storage and handling of the fuel oil with the additive, particularly with the neat additive, at such temperatures. Suitably, the fuel oil additive (A) is suitable for use in cold climates, e.g. at ambient temperatures below 0°C, and it may be supplied in pure form or even in highly concentrated form for addition to low sulphur content fuel oils in such cold climates, thereby reducing transport and storage costs and reducing top-treat rate requirements.

[0046] Suitably, the fuel oil additive (A) as defined and identified herein may have a viscosity of less than or equal to 10000, suitably less than or equal to 9000, suitably less than or equal to 8000, suitably less than or equal to 7000, suitably less than or equal to 6000 cSt when measured at 0°C. The measurement of the viscosity of the fuel oil additive (A) at a specific temperature is conventional, and methods for carrying out the measurement are known to those skilled in the art. Commercial devices such as the Anton Paar SVM 3001 viscometer with a temperature ramp program are available.

[0047] Suitably, the relatively low viscosity of the fuel oil additive (A) may further enable, if desired, the provision and use of additive concentrates comprising relatively higher amounts of the fuel oil additive (A) on an active ingredients basis and reduced amounts of inert diluents compared to additive concentrates comprising known lubricity additives.

[0048] Thus, according to a tenth aspect, there is provided an additive concentrate suitable for use as an additive for a middle distillate fuel oil having a sulphur content of 0.2 wt.-%, based on the total weight of the fuel oil, the additive concentrate comprising:

[0049] (a) a major amount of the fuel oil additive (A) identified and defined in the first aspect, based on the total mass of the additive concentrate; and

[0050] (b) minor amounts of inert organic solvents, based on the total mass of the additive concentrate.

[0051] Suitably, the fuel oil additive (A) may be present in an amount greater than or equal to 60, suitably greater than or equal to 65, suitably greater than or equal to 70, suitably greater than or equal to 75, suitably greater than or equal to 80 mass % on an active ingredient basis, based on the total mass of the additive concentrate.

[0052] Suitably, the inert organic solvent may be present in an amount of less than or equal to 40, suitably less than or equal to 35, suitably less than or equal to 30, suitably less than or equal to 25, suitably less than or equal to 20 mass % on an active ingredient basis, based on the total mass of the additive concentrate. Suitable inert organic solvents are known to those skilled in the art and include hydrocarbon solvents, such as Solvesso TM 100 and 150 and Isopar TM Suitably, the inert organic solvent dissolves, solubilizes or otherwise disperses the fuel oil additive and any other optional components defined herein which may be present in the additive concentrate.

[0053] Suitably, the additive concentrate of the tenth aspect may further comprise an optional antistatic additive (B) as defined and identified herein, present in a minor amount. Suitably, the antistatic additive (B), when present, may be present in an amount of less than 10, suitably less than 7.5, suitably less than 5 mass % on an active ingredient basis based on the total mass of the additive concentrate. In one embodiment, the additive concentrate further comprises an antistatic additive (B) present in a minor amount based on the total mass of the additive concentrate.

[0054] Suitably, the additive concentrate may further comprise, in addition to the fuel oil additive (A) and the antistatic additive (B) (when present), one or more additional optional additives as defined herein, each present in a minor amount based on the total mass of the concentrate.

[0055] Suitably, the fuel oil additive (A) defined in each aspect of the present invention may comprise an alkyl neo-monocarboxylic acid having a total of 5 to 30 carbon atoms and an aliphatic acyclic (C2 to C4) having a total of 2 to 18 carbon atoms and a total of 2 to 8 hydroxyl groups. 18 Suitably, the fuel oil additive (A) may include one or more ester groups, which may be formed by the aliphatic acyclic (C2 to C 18 ) can be obtained by reaction of one or more of the available hydroxyl groups of the alkanol with the monocarboxylic acid functional group (or a reactive derivative thereof) of the alkyl neo-monocarboxylic acid.

[0056] Suitably, the fuel oil additive (A) may contain up to 8 ester groups in the molecule, wherein each of the ester groups may be connected by the aliphatic acyclic (C2 to C 18 ) alkanols are obtained by reaction of the available hydroxyl groups with the monocarboxylic acid functional groups (or reactive derivatives thereof) of the alkyl neo-monocarboxylic acids; aliphatic acyclic (C2 to C 18 )Alkanols have up to 8 available hydroxyl groups.

[0057] Suitably, the fuel oil additive (A) may contain a single ester group in the molecule, which may be formed by the aliphatic acyclic (C2 to C 18 ) is obtained by reacting only one available hydroxyl group of an alkanol with the monocarboxylic acid functional group of the alkyl neo-monocarboxylic acid (or a reactive derivative thereof) (i.e. the fuel oil additive represents a monoester). Suitably, the fuel oil additive (A) may comprise two ester groups in the molecule, wherein each of the two ester groups may be obtained by reacting the aliphatic acyclic (C2 to C 18 The fuel oil additive (A) may contain three ester groups, wherein each of the three ester groups may be obtained by reacting two separately available hydroxyl groups of the alkanol with the monocarboxylic acid functional group of the alkyl neo-monocarboxylic acid (or a reactive derivative thereof) (i.e. the fuel oil additive represents a diester). Suitably, the fuel oil additive (A) may contain three ester groups, wherein each of the three ester groups may be obtained by reacting two separately available hydroxyl groups of the alkanol with the monocarboxylic acid functional group of the alkyl neo-monocarboxylic acid (or a reactive derivative thereof). 18 ) are obtainable by reaction of three individually available hydroxyl groups of the alkanol with the monocarboxylic acid functional groups (or reactive derivatives thereof) of the alkyl neo-monocarboxylic acid (ie the fuel oil additive represents a triester).

[0058] In a preferred embodiment of each aspect of the present invention, the fuel oil additive (A) comprises a single ester group in the molecule, which can be obtained by the aliphatic acyclic (C2 to C 18 ) is obtainable by reaction of only one of the available hydroxyl groups of the alkanol with the monocarboxylic acid functionality (or a reactive derivative thereof) of the alkyl neo-monocarboxylic acid (ie the fuel oil additive (A) represents a monoester).

[0059] Suitably, it can be used, for example, by reacting with aliphatic acyclic (C2 to C 18 The alkyl neo-monocarboxylic acid obtained by reacting the alkyl alcohol with the fuel oil additive (A) has a total of 5 to 30 carbon atoms and comprises acetic acid substituted by three alkyl groups at the α carbon atom (i.e., α-trialkyl substituted acetic acid, wherein the total number of carbon atoms of the three alkyl groups is 3 to 28). Suitably, the alkyl neo-monocarboxylic acid has a total of 5 to 20, suitably 5 to 14, suitably 5 to 10 carbon atoms. Suitable alkyl neo-monocarboxylic acids include α-trialkyl substituted acetic acids, such as neopentanoic acid, neohexanoic acid, neoheptanoic acid, neooctanoic acid, neononanoic acid, neodecanoic acid and neotetradecanoic acid, suitably neopentanoic acid and neodecanoic acid.

[0060] In one embodiment, the alkyl neo-monocarboxylic acid comprises α-trialkyl substituted acetic neo-decanoic acid.

[0061] Suitably, the aliphatic acyclic (C2 to C 2) carbonyl group may be reacted with an alkyl neo-monocarboxylic acid (or a reactive derivative thereof) to obtain the fuel oil additive (A). 18 )alkanol comprises at least one primary hydroxyl functional group. Suitably, the aliphatic acyclic (C2 to C 18 )The alkanol does not include a tertiary hydroxyl functional group.

[0062] In one embodiment, the aliphatic acyclic (C2 to C 18 ) alkanols contain only primary hydroxyl functional groups. Such aliphatic acyclic (C2 to C 18 Examples of the alkanol include ethylene glycol; 1,3-propylene glycol; 1,4-butanediol; pentaerythritol and pentaerythritol derivatives such as dipentaerythritol and tripentaerythritol; and trimethylolpropane and trimethylolpropane derivatives such as di-trimethylolpropane.

[0063] In one embodiment, the aliphatic acyclic (C2 to C 18 )alkanol comprises a combination of one or more primary hydroxyl functional groups and one or more secondary hydroxyl functional groups. Such aliphatic acyclic (C2 to C 18 Examples of the alkanol include: alkylene polyols such as 1,2-propylene glycol and 1,3-butylene glycol; glycerol and glycerol derivatives such as diglycerol, triglycerol and hexaglycerol.

[0064] In a preferred embodiment, the aliphatic acyclic (C2 to C4) hydrocarbons which can be reacted with an alkyl neo-monocarboxylic acid (or a reactive derivative thereof) to obtain the fuel oil additive (A) are 18 )Alkanols include glycerol and glycerol derivatives, such as diglycerol, triglycerol and hexaglycerol, especially glycerol.

[0065] In a more preferred embodiment, the fuel additive (A) comprises an ester of neodecanoic acid and glycerol (i.e. an ester obtainable by reaction of glycerol with neodecanoic acid or a reactive derivative thereof), in particular a monoester of neodecanoic acid and glycerol. Suitably, such a fuel additive (A) can also be obtained by acid-catalyzed hydrolysis of glycidyl ester of neodecanoic acid.

[0066] Thus, according to an eleventh aspect, there is provided a fuel oil additive (A) for use as an additive for a middle distillate fuel oil having a sulphur content of 0.2 wt% or less, wherein the fuel oil additive (A) is as defined and identified herein.

[0067] In this specification, if the following words and expressions are used, they shall have the meanings given below:

[0068] definition

[0069] “Active ingredient” or “(ai)” means an additive material that is not a diluent or solvent;

[0070] "Comprising" or any cognates specify the presence of the stated elements, steps or integers or components, but does not exclude the presence or addition of one or more other elements, steps, integers, components or combinations thereof. The expression "consisting of" or "consisting essentially of" or cognates may be encompassed by "comprising" or any cognates. The expression "consisting essentially of" allows the inclusion of substances that do not materially affect the characteristics of the composition to which it is applied. The expression "consisting of" or cognates means that only the specified elements, steps, integers, components or combinations thereof mentioned in the expression are present;

[0071] "Hydrocarbon fluid" means a hydrocarbon liquid or oil that is soluble, dissolvable, miscible (although not necessarily in all proportions) with a fuel oil composition;

[0072] "Hydrocarbyl" refers to a monovalent group containing only hydrogen and carbon atoms and bonded directly to the rest of the compound via a single carbon atom. The term "hydrocarbyl" includes "alkyl", "alkenyl" and "allyl". The hydrocarbyl is preferably an aliphatic hydrocarbyl, more preferably an aliphatic acyclic hydrocarbyl, such as an aliphatic acyclic alkyl or an acyclic alkenyl. The hydrocarbyl defined herein may be a straight chain or branched chain;

[0073] "Alkyl" refers to a monovalent alkyl group (i.e., a monovalent hydrocarbon group containing no double or triple bonds) directly bonded to the rest of the compound via a single carbon atom. Alkyl groups can be straight or branched chains. Preferred alkyl groups are acyclic alkyl groups.

[0074] "Alkenyl group" refers to a monovalent alkenyl group (i.e., a monovalent hydrocarbon group containing one or more carbon-carbon double bonds) directly bonded to the rest of the compound via a single carbon atom. The alkenyl group can be a straight-chain or branched chain. Preferred alkenyl groups are acyclic alkenyl groups.

[0075] "Alkylene" is synonymous with "alkanediyl" and refers to a divalent saturated hydrocarbon radical (ie, a divalent hydrocarbon radical containing no double or triple bonds) derived from an alkane by removing hydrogen atoms from two different carbon atoms; it may be linear or branched chain.

[0076] "aliphatic acyclic (C2 to C4) having a total of 2 to 18 carbon atoms and a total of 2 to 8 hydroxyl groups 18The term "alkanol" includes alkanols comprising, preferably consisting of, one or more aliphatic acyclic alkyl chains, wherein the total number of carbon atoms provided by the one or more alkyl chains is from 2 to 18, and wherein the one or more aliphatic alkyl chains are terminated and / or substituted with hydroxyl functional groups such that the total number of hydroxyl functional groups present in the alkanol is from 2 to 8. Suitably, the aliphatic acyclic (C2 to C 18 )Alkanols can be considered to represent polyols because they include 2 or more hydroxyl functional groups. The most preferred aliphatic acyclic (C2 to C 18 ) the alkanol is glycerol;

[0077] "Alkyl neo-monocarboxylic acids having a total of 5 to 30 carbon atoms" may be defined as acetic acid substituted with three alkyl groups at the alpha carbon atom (α-trialkyl substituted acetic acid) or acetic acid substituted with two alkyl groups (α-dialkyl substituted acetic acid), wherein the total number of carbon atoms present, including the carbon atoms of the monocarboxylic acid functional group, is 5 to 30. Preferably, the alkyl neo-monocarboxylic acid comprises acetic acid substituted with three alkyl groups at the alpha carbon atom (α-trialkyl substituted acetic acid). The preferred neo-monocarboxylic acid is neodecanoic acid;

[0078] "Anti-static additive" refers to an additive that is capable of dissipating static charge from fuel oil, especially low sulfur content fuel oil. Examples of antistatic agents include a two-component mixture of polysulfone and polymeric polyamine reaction product as disclosed in, for example, U.S. Patent 3,917,466. Such antistatic agents are marketed by Innospec as STADIS TM sell;

[0079] "Cold climate" refers to a climate wherein the ambient temperature may be less than or equal to 10°C, suitably less than or equal to 5°C, suitably less than or equal to 0°C, suitably less than or equal to -5°C.

[0080] "Halo" or "halogen" includes fluorine, chlorine, bromine and iodine;

[0081] As used herein, "oil soluble" or "oil dispersible" or cognate terms do not necessarily mean that the compound or additive is soluble, dissolvable, miscible or capable of being suspended in a fuel oil composition in all proportions. However, these mean that the one or more additives are, for example, soluble or stably dispersible in a fuel oil composition comprising a middle distillate fuel oil having a sulfur content of 0.2 wt. % or less. In addition, the additional incorporation of other additives may also allow the incorporation of higher amounts of a particular additive, if desired;

[0082] "Major amount" means at least or more than 50% by mass of the composition, preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more;

[0083] "Minor amount" means less than 50% by mass of the composition, preferably less than or equal to 40% by mass, more preferably less than or equal to 30% by mass, and even more preferably less than or equal to 20% by mass;

[0084] An "effective minor amount" with respect to an additive means a minor amount of such additive in a fuel oil composition comprising a middle distillate fuel oil having a sulfur content of 0.2 wt. % or less to provide the desired technical effect;

[0085] "obtainable by..." or "obtainable by..." with respect to a compound means that the title compound can be obtained by or from the reaction of the specified reactants, but does not exclude obtaining the title compound by alternative synthetic routes;

[0086] "ppm" means parts per million by mass based on the total mass of the composition;

[0087] Unless otherwise stated, all percentages reported are mass % on an active ingredient basis, ie without taking into account carrier or diluent oil.

[0088] Suitably, it is to be understood that the various components used (essential as well as optimal and conventional) may react under conditions of formulation, storage or use, and the invention also provides products obtainable or obtained as a result of any such reaction.

[0089] Suitably, it is to be understood that any upper and lower limits of the amount, scope and ratio listed herein can be combined independently. Accordingly, any upper and lower limits of the amount, scope and ratio related to the specific technical features of the present invention listed herein can be combined independently with any upper and lower limits of the amount, scope and ratio related to one or more other specific technical features of the present invention listed herein. In addition, any specific technical features of the present invention and all preferred variants thereof can be combined independently with any other specific technical features and all preferred variants thereof, whether or not these features are presented as preferred features.

[0090] Suitably it will be appreciated that preferred features of each aspect of the invention are to be taken as preferred features of each other aspect of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0092] Fuel oil additives (A)

[0093] The fuel oil additive (A) represents an alkyl neo-monocarboxylic acid as defined and identified herein and an aliphatic acyclic (C2 to C 18) esters of alkanols. Monoesters are most preferred. Suitably, the fuel oil additive (A) may be prepared by reacting the alkyl neo-monocarboxylic acid (or its reactive derivative) and the aliphatic acyclic (C2 to C 18 ) is obtained by esterification of alkanol.

[0094] (i) aliphatic acyclic (C2 to C 18 )Alkanol (Aliphatic acyclic (C2 to C 18 )alkanol

[0095] Aliphatic acyclic (C2 to C 18 )alkanol has a total of 2 to 18 carbon atoms and a total of 2 to 8 hydroxyl functional groups. 18 ) alkanol comprises one or more alkyl chains, wherein the one or more alkyl chains are terminated and / or substituted with hydroxyl functional groups so as to be present in the aliphatic acyclic (C2 to C 18 )The total number of hydroxyl functional groups in the alkanol is 2 to 8.

[0096] Suitably, the aliphatic acyclic (C2 to C 18 )Alkanols can be considered to represent polyols since they contain 2 or more hydroxyl functional groups.

[0097] Suitably, the aliphatic acyclic (C2 to C 18 )alkanol contains at least one primary hydroxyl functional group. In other words, the aliphatic acyclic (C2 to C 18 )alkanol, one or more of the alkyl chains are terminated by at least one primary hydroxyl function, i.e., a -CH2-OH group.

[0098] In some embodiments, the aliphatic acyclic (C2 to C 18 )Alkanols may contain only primary hydroxyl functional groups, i.e. aliphatic acyclic (C2 to C 18 ) The alkanol comprises 2 to 8 hydroxyl functions, and each of the hydroxyl functions represents a primary hydroxyl function.

[0099] Aliphatic acyclic (C2 to C 18 Examples of alkanols include: (C2 to C 18 )Alkylene glycol ((C2 to C 18 )alkylene glycols), such as ethylene glycol and neopentyl glycol; (C2 to C 18 ) alkylene polyols such as 1,3-propylene glycol and 1,4-butylene glycol; polyethylene glycols such as diethylene glycol and triethylene glycol; pentaerythritol and pentaerythritol derivatives such as dipentaerythritol and tripentaerythritol; and trimethylolpropane and trimethylolpropane derivatives such as di-trimethylolpropane.

[0100] In alternative embodiments, the aliphatic acyclic (C2 to C 18 )The alkanol may contain a combination of one or more primary hydroxyl functional groups and one or more secondary hydroxyl functional groups.

[0101] An aliphatic acyclic (C2 to C4) hydrocarbon containing a combination of one or more primary hydroxyl functional groups and one or more secondary hydroxyl functional groups. 18 Examples of alkanols include: (C2 to C 18 ) alkylene polyols such as 1,2-propylene glycol and 1,3-butylene glycol; glycerol and glycerol derivatives such as diglycerol, triglycerol and hexaglycerol.

[0102] In a preferred embodiment, the aliphatic acyclic (C2 to C 18 )alkanol contains a combination of one or more primary hydroxyl functional groups and one or more secondary hydroxyl functional groups. Preferably, the aliphatic acyclic (C2 to C 18 )Alkanols include glycerol and glycerol derivatives, such as diglycerol, triglycerol and hexaglycerol, especially glycerol.

[0103] Suitably, the aliphatic acyclic (C2 to C 18 )The alkanol does not contain a tertiary hydroxyl functional group.

[0104] Suitably, present in the aliphatic acyclic (C2 to C 18 The one or more alkyl chains in the alkanol may each independently be optionally interrupted by an oxygen atom. 18 )alkanol may contain one or more oxyalkylenyl moieties, thus the term "aliphatic acyclic (C2 to C 18 "Alkanols" include aliphatic acyclic (C2 to C18) hydrocarbons having a total of 2 to 18 carbon atoms and a total of 2 to 8 hydroxyl groups. 18 ) ether-alkanol. Aliphatic acyclic (C2 to C 18 Examples of ether-alkanols include: derivatives of glycerol, such as diglycerol, triglycerol and hexaglycerol; polyalkylene glycols, such as diethylene glycol, triethylene glycol, dipropylene glycol; derivatives of pentaerythritol, such as dipentaerythritol and tripentaerythritol; and derivatives of trimethylolpropane, such as di-trimethylolpropane.

[0105] In a preferred embodiment, the aliphatic acyclic (C2 to C 18 )The one or more alkyl chains in the alkanol are each not interrupted by an oxygen atom.

[0106] Suitably, the aliphatic acyclic (C2 to C 18) The alkanol has a total of 2 to 8, preferably 3 to 8, more preferably 3 to 6, more preferably 3 or 4, most preferably 3 hydroxyl functional groups.

[0107] The most preferred aliphatic acyclic (C2 to C 18 )The alkanol is glycerol.

[0108] Suitably, the aliphatic acyclic (C2 to C4) radical has a total of 2 to 18 carbon atoms and a total of 2 to 8 hydroxyl groups. 18 )alkanol (the aliphatic acyclic (C2 to C 18 )alkanol optionally comprising one or more oxyalkylenyl moieties) can be represented by a compound of formula I:

[0109]

[0110] wherein: R1 represents an aliphatic acyclic alkyl chain having a total of 1 to 17 carbon atoms, the aliphatic acyclic alkyl chain being optionally interrupted by one or more oxygen atoms; (CH2OH) m represents a primary hydroxyl functional group and m is an integer from 1 to 3; (CH2OH) n represents a primary hydroxyl functional group and n is an integer from 0 to 3; and (OH) s represents a secondary hydroxyl functional group and s is an integer from 0 to 6; and the sum of m, n and s is an integer from 2 to 8.

[0111] It is important to recognize that aliphatic acyclic (C2 to C 18 ) The alkanol contains at least one primary hydroxyl function, ie m in the compound of formula I is an integer from 1 to 3, and the total number of hydroxyl functions present in the compound of formula I is from 2 to 8.

[0112] In some embodiments, the aliphatic acyclic (C2 to C 18 )alkanol contains only primary hydroxyl functional groups, for example, in the compound of formula I, m and n are each independently an integer from 1 to 3 and s is 0. Such aliphatic acyclic (C2 to C 18 Examples of )alkanols are specified herein.

[0113] Suitably, when the aliphatic acyclic (C2 to C 18 )alkanol contains only primary hydroxyl functional groups, m and n in the compound of formula I are each independently an integer from 1 to 3, s is 0, and the total number of hydroxyl functional groups present in the compound of formula I is from 2 to 6. In one embodiment, when the aliphatic acyclic (C2 to C 18 )When the alkanol contains only primary hydroxyl functional groups, the total number of hydroxyl functional groups present in the compound of formula I is 2, for example, m and n in the compound of formula I are both 1 and s is 0, or m is 2, n and s are 0 in the compound of formula I.

[0114] In some embodiments, the aliphatic acyclic (C2 to C 18 )alkanol contains a combination of one or more primary hydroxyl functional groups and one or more secondary hydroxyl functional groups, i.e., s in the compound of formula I is an integer from 1 to 6, m in the compound of formula I is an integer from 1 to 3, and n in the compound of formula I is an integer from 0 to 3, so that the total number of hydroxyl functional groups present in the compound of formula I is 2 to 8.

[0115] Preferably, the aliphatic acyclic (C2 to C 18 )alkanol contains one or more secondary hydroxyl groups in addition to the primary hydroxyl functional groups, i.e., s in the compound of formula I is an integer from 1 to 6, m in the compound of formula I is an integer from 1 to 3, and n in the compound of formula I is an integer from 0 to 3, so that the total number of hydroxyl functional groups present in the compound of formula I is 2 to 8. Aliphatic acyclic (C2 to C4) hydrocarbons having a combination of primary and secondary hydroxyl functional groups 18 Examples of )alkanols are specified herein.

[0116] Suitably, when the aliphatic acyclic (C2 to C 18 )alkanol contains a combination of primary and secondary hydroxyl functional groups, m and n in the compound of formula I are each independently an integer from 1 to 3, s is an integer from 1 to 6, and the total number of hydroxyl functional groups present in the compound of formula I is 2 to 8. Preferably, when the aliphatic acyclic (C2 to C 18 )alkanol contains a combination of primary and secondary hydroxyl functional groups, m and n in the compound of formula I each represent 1, s is an integer from 1 to 6, and the total number of hydroxyl functional groups present in the compound of formula I is 3 to 8. More preferably, when the aliphatic acyclic (C2 to C 18 )alkanol contains a combination of primary and secondary hydroxyl functional groups, m and n in the compound of formula I each represent 1, s is an integer from 1 to 3, and the total number of hydroxyl functional groups present in the compound of formula I is 3 to 6. Most preferably, when the aliphatic acyclic (C2 to C 18 )When the alkanol contains a combination of primary and secondary hydroxyl functional groups, m, n and s in the compound of formula I each represent 1, and the total number of hydroxyl functional groups present in the compound of formula I is 3.

[0117] Suitably, R in the compound of formula I 1 represents one or more aliphatic acyclic alkyl chains having a total of 1 to 17 carbon atoms and which is terminated by one or more primary hydroxyl functions and optionally substituted by one or more secondary hydroxyl functions, such that the total number of hydroxyl functions present in the compounds of formula I is 2 to 8.

[0118] Suitably, R 1 The one or more aliphatic acyclic alkyl chains represented by may form a single continuous structure.1 The alkyl chain structure may be linear or, if there are a sufficient number of carbon atoms, branched. 1 represents an aliphatic acyclic alkyl straight chain having 1 to 17 total carbon atoms.

[0119] Suitably, R 1 R may represent an aliphatic acyclic alkyl chain having a total of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17 carbon atoms. 1 The aliphatic acyclic alkyl chain represented may be optionally interrupted by one or more oxygen atoms when there are a sufficient number of carbon atoms. 1 The aliphatic acyclic alkyl chains represented are each not interrupted by oxygen atoms.

[0120] Suitably, R 1 represents an aliphatic acyclic alkyl chain having a total number of 1 to 16, preferably 1 to 12, more preferably 1 to 10, even more preferably 1 to 8, even more preferably 1 to 6, even more preferably 1 to 4 carbon atoms.

[0121] Suitably, R 1 represents an aliphatic acyclic alkyl straight chain having a total number of 1 to 16, preferably 1 to 12, more preferably 1 to 10, still more preferably 1 to 8, still more preferably 1 to 6, still more preferably 1 to 4 carbon atoms.

[0122] Particularly preferred compounds of formula I include those wherein:

[0123] (i)R 1 represents CH; and m, n and s each represent 1 (i.e., glycerol);

[0124] (ii) R 1 represents a C4 alkyl straight chain interrupted by a single oxygen atom, m and n each represent 1 and s represents 2 (e.g. diglycerol);

[0125] (iii) R 1 represents a C7 alkyl straight chain interrupted by two oxygen atoms, m and n each represent 1 and s represents 3 (e.g. triglycerol); and

[0126] (iv) R 1 represents C interrupted by five oxygen atoms 16 The alkyl group is a straight chain, m and n each represent 1 and s represents 6 (eg hexaglycerol).

[0127] The most preferred compounds of formula I are those wherein R 1represents CH; and m, n and s each represent 1 (i.e. glycerol).

[0128] (ii) Alkyl neo-monocarboxylic acid

[0129] Alkyl neo-monocarboxylic acid can be defined as acetic acid substituted by three alkyl groups at the α carbon atom (α-trialkyl substituted acetic acid) or acetic acid substituted by two alkyl groups (α-dialkyl substituted acetic acid). Preferably, the alkyl neo-monocarboxylic acid includes acetic acid substituted by three alkyl groups at the α carbon atom (α-trialkyl substituted acetic acid).

[0130] Suitably the alkyl neo-monocarboxylic acid has a total number of 5 to 30, suitably 5 to 20, suitably 5 to 14, suitably 5 to 10 carbon atoms.

[0131] The alkyl neo-monocarboxylic acid can be represented by the compound of formula II:

[0132]

[0133] Where: R 2 represents hydrogen or C1 to C 18 Alkyl, R 3 and R 4 Each independently represents C1 to C 18 Alkyl, and R 2 , R 3 and R 4 The total number of carbon atoms together ranges from 3 to 28.

[0134] Preferably, the alkyl neo-monocarboxylic acid comprises an α-trialkyl substituted acetic acid, which can be represented by the compound of formula II, wherein R 2 Represents C1 to C 18 Alkyl, R 3 and R 4 Each independently represents C1 to C 18 Alkyl, and R 2 , R 3 and R 4 The total number of carbon atoms together ranges from 3 to 28.

[0135] Suitably, R 2 , R 3 and R 4 The alkyl groups which may be independently represented in the compounds of formula II may be selected from C1 to C 18 Alkyl, including methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl and all structural isomers thereof. Suitably, R2 , R 3 and R 4 The alkyl groups which may each independently be represented may be linear or branched, cyclic, partially cyclic / acyclic, or acyclic.

[0136] Suitably, R 2 , R 3 and R 4 The alkyl groups which may be independently represented in the compounds of formula II include linear or branched acyclic C1 to C 18 Preferably, R 2 , R 3 and R 4 The alkyl groups which may be independently represented include linear or branched acyclic C1 to C 12 , more preferably C1 to C 10 , still more preferably C1 to C8, still more preferably C1 to C6 alkyl.

[0137] Suitably, R 2 , R 3 and R 4 In the compound of formula II, at least one of the alkyl groups which may each independently represent a branched acyclic C1 to C 12 , more preferably C1 to C 10 , still more preferably C1 to C8, still more preferably C1 to C6 alkyl.

[0138] Suitably, R in the compound of formula II 2 , R 3 and R 4 The total number of carbon atoms together is 3 to 18, more preferably 3 to 12, even more preferably 3 to 8.

[0139] The most preferred alkyl neo-monocarboxylic acid is neodecanoic acid, which can be represented by the compound of formula II, wherein R 2 , R 3 and R 4 As defined for compounds of formula II, and wherein R 2 , R 3 and R 4 Together they are 8.

[0140] Suitable alkyl neo-monocarboxylic acids include α-trialkyl substituted acetic acids such as neopentanoic acid, neohexanoic acid, neoheptanoic acid, neooctanoic acid, neononanoic acid, neodecanoic acid and neotetradecanoic acid, preferably neopentanoic acid, neononanoic acid and neodecanoic acid, especially neodecanoic acid.

[0141] Suitably, the alkyl neo-monocarboxylic acid comprises a compound of formula II, wherein: R 2 Represents methyl or ethyl; R 3 represents a C1 to C4 acyclic alkyl group; R4 Represents C1 to C 10 acyclic alkyl; and R 2 , R 3 and R 4 The total number of carbon atoms together is 3 to 16. Preferably, the alkyl neo-monocarboxylic acid comprises a compound of formula II, wherein: R 2 Represents methyl or ethyl; R 3 represents a C1 to C4 acyclic alkyl group; R 4 represents a C1 to C6 acyclic alkyl group; and R 2 , R 3 and R 4 The total number of carbon atoms together is 3 to 12. More preferably, the alkyl neo-monocarboxylic acid comprises a compound of formula II, wherein: R 2 Represents methyl; R 3 represents a C1 to C3 acyclic alkyl group; R 4 represents a C1 to C6 acyclic alkyl group; and R 2 , R 3 and R 4 The total number of carbon atoms together is 3 to 8, preferably 8.

[0142] Suitably, the alkyl neo-monocarboxylic acids identified herein can be purchased from suppliers such as ExxonMobil Product Solutions (22777 Springwoods Village Parkway Spring, Texas 77389-1425, USA) Chemical and Hexion Inc. Administration (180 E Broad Street, Columbus, Ohio 43215, USA). Alkyl neo-monocarboxylic acids can also be prepared by the Koch process from olefins, carbon monoxide and water as described by H. Koch in Brenstaff. Chem. 36, 321 (1955). Additional synthetic procedures for preparing alkyl neo-monocarboxylic acids can be found in British Patents GB 960,011 and GB 998,974 and U.S. Patent 3,349,107.

[0143] Suitably, the compound comprises an alkyl neo-monocarboxylic acid as defined and identified herein and an aliphatic acyclic (C2 to C 18 ) The fuel oil additive of the ester of alkanol can be represented by the compound of formula III:

[0144]

[0145] Where: R 1 , m, n and s are as defined for the compound of formula 1;

[0146] X, Y and Z each independently represent an alkyl neo-monocarboxylic acid moiety of formula IV:

[0147]

[0148] R 2 , R 3 and R 4 Each is as defined for the compound of formula II.

[0149] Suitably, preferred additive compounds of formula III include additive compounds derived from glycerol and may be represented by compounds of formula IIIA, IIIB, IIIC, IIID and IIIE:

[0150]

[0151] Where R 2 , R 3 and R 4 Each is as defined for the compound of formula II.

[0152] Suitably, in the compounds of formula IIIA, IIIB, IIIC, IIID and IIIE, R 2 Represents methyl or ethyl; R 3 represents a C1 to C4 acyclic alkyl group; R 4 Represents C1 to C 10 acyclic alkyl; and R 2 , R 3 and R 4 The total number of carbon atoms together is 3 to 16. Suitably, in the compounds of formula IIIA, IIIB, IIIC, IIID and IIIE, R 2 Represents methyl or ethyl; R 3 represents a C1 to C4 acyclic alkyl group; R 4 represents a C1 to C6 acyclic alkyl group; and R 2 , R 3 and R 4 The total number of carbon atoms together is 3 to 12. Suitably, in the compounds of formula IIIA, IIIB, IIIC, IIID and IIIE, R 2 Represents methyl; R 3 represents a C1 to C3 acyclic alkyl group; R 4 represents a C1 to C6 acyclic alkyl group; and R 2 , R 3 and R 4 The total number of carbon atoms together is 3 to 8. Preferably, in the compounds of formula IIIA, IIIB, IIIC, IIID and IIIE, R 2 , R 3 and R 4The total number of carbon atoms together is 8.

[0153] Suitably, the fuel oil additive preferably comprises a monoester, and compounds of formula IIIA and IIIB are particularly preferred fuel oil additives, especially the compound of formula IIIB.

[0154] (iii) Preparation of fuel oil additive (A)

[0155] Fuel oil additives can be synthesized by standard chemical esterification techniques known to those skilled in the art and exemplified herein. For example, an alkyl neo-monocarboxylic acid can be converted to an activated acid derivative, such as the corresponding acid halide, which is then reacted with an appropriate aliphatic acyclic (C2 to C 18 )Alkyl alcohol condensation.

[0156] A preferred synthetic route for preparing fuel oil additives involves converting an alkyl neo-monocarboxylic acid to the corresponding glycidyl ester derivative, for example by reacting the alkyl neo-monocarboxylic acid with epichlorohydrin (see, for example, US 2014 / 0316030 A), followed by acid-catalyzed hydrolysis of the epoxide ring to form the glyceride derivative.

[0157] It will be appreciated and is common knowledge to those skilled in the art that various strategies for protecting and deprotecting groups can be used during the course of the synthetic procedures to prepare the appropriate aliphatic acyclic (C2 to C 18 )alkanol and alkyl neo-monocarboxylic acid to maximize the yield of the target ester.

[0158] Antistatic Additives (B)

[0159] Suitably, the antistatic additive (B) comprises an olefin polysulfone and a polymeric polyamine reaction product of epichlorohydrin and an aliphatic primary monoamine or an N-aliphatic hydrocarbyl alkylene diamine, or a sulfonate of a polymeric polyamine reaction product.

[0160] Suitably, the weight average molecular weight of the polysulfone is in the range of 10,000 to 1,500,000, suitably in the range of 50,000 to 900,000, for example 100,000 to 500,000.

[0161] Suitably, the weight ratio of the polysulfone component to the polymeric polyamine component is in the range of 100:1 to 1:100.

[0162] Suitably, the olefins useful in preparing the polysulfone have from 6 to 20 carbon atoms, suitably from 6 to 18 carbon atoms. Particularly preferred is 1-decene polysulfone. The preparation of these materials is known in the art, as described, for example, in US 3,917,466.

[0163] The polymeric polyamine component can be prepared by heating an amine with epichlorohydrin in a molar ratio of 1:1 to 1:1.5 at a temperature of 50°C to 100°C. Suitable aliphatic primary amines have 8 to 24 carbon atoms, suitably 8 to 12 carbon atoms. The aliphatic group is preferably an alkyl group. If an N-aliphatic hydrocarbyl alkylene diamine is used, the aliphatic hydrocarbyl group suitably has 8 to 24 carbon atoms and is preferably an alkyl group. Suitably, the alkylene group has 2 to 6 carbon atoms. A preferred N-aliphatic hydrocarbyl alkylene diamine is N-aliphatic hydrocarbyl 1,3-propylene diamine. These materials are commercially available, and a preferred example is the polymerization reaction product of N-tallow-1,3-propylene diamine and epichlorohydrin. The polymeric polyamine reaction product preferably has a degree of polymerization of about 2 to 20. These materials are also described in US 3,917,466.

[0164] Suitably, the polymeric polyamine reaction product is in the form of a sulfonate. Useful are oil soluble sulfonic acids such as alkanesulfonic acids or arylsulfonic acids. A preferred example is dodecylbenzenesulfonic acid.

[0165] The antistatic additive (B) is most preferably a commercial product available from Innospec Inc. 450, which Applicants understand and intend to be described by the above definition of component (B). 425 (which is considered 450 in diluted form) is also suitable.

[0166] Suitably, other antistatic additives B include, for example, Cestoil Northshore ST 3425, Dorf Ketal SR 1795 and Afton AvGuard SDA, each of which is believed to contain a sulphonic acid compound such as dodecylbenzene sulphonic acid or dinonylnaphthalene sulphonic acid.

[0167] Suitably, the weight:weight ratio of the fuel additive (A) to the antistatic additive (B) in the fuel oil composition is from 5:1 to 1000:1, preferably from 50:1 to 500:1, for example from 100:1 to 500:1.

[0168] Fuel oil additive composition

[0169] As discussed herein, the fuel oil additive can be used in low sulfur content fuel oil. Advantageously, the fuel oil additive generally exhibits a desirable low viscosity, especially at low ambient temperatures (e.g., 0° C. or below), which may facilitate adding the pure additive directly to the low sulfur content fuel oil, especially at such low ambient temperatures. Accordingly, the fuel oil additive can be supplied in pure form or even in a highly concentrated form for addition to low sulfur content fuel oil, thereby reducing transportation costs associated with the supply of the additive and reducing top-treat rate requirements.

[0170] If convenient, the fuel oil additive can be in the form of an additive composition (referred to as an additive concentrate). The additive composition can additionally include an inert organic liquid, which is used to dissolve, solubilize or otherwise disperse the components of the additive composition. The resulting additive composition may be more convenient to use or store, and may be more easily metered into the fuel oil. Suitable inert organic liquids include hydrocarbon solvents, such as naphtha, kerosene, diesel and heating oil (heater oil), aromatics, such as those sold under the name of 'SOLVESSO' trade name, alcohols, ethers and other oxygenates and paraffins, such as hexane, pentane and isoparaffins. The organic liquid should be miscible with the fuel oil in the sense that it can physically mix with the fuel oil to form a solution or dispersion in the fuel oil. Select liquid according to its compatibility with the additive composition involved and the fuel oil, and it is a conventional selection problem for those skilled in the art. Suitably, the additive composition may suitably comprise less than 50, typically less than 40, suitably less than 30, suitably less than 20 mass % of inert organic liquid, the remainder being the fuel oil additive (A) and the optional antistatic additive (B) and any additional optional additives required to achieve different purposes in the fuel oil. Some optional additional additives are described below.

[0171] Low sulfur fuel oil

[0172] The fuel oil may be a petroleum-based fuel oil, in particular a middle distillate fuel oil. Such distillate fuel oils typically boil in the range of 110° C. to 500° C., for example 150° C. to 400° C. The present invention is applicable to all types of middle distillate fuel oils, including distillates having a 90%-20% boiling point temperature difference of 50° C. or more measured according to ASTM D-86.

[0173] Fuel oil can include atmospheric distillate or vacuum distillate, cracked gas oil, or a blend of any proportion of straight run and thermally and / or catalytically cracked distillates. The most common petroleum fraction fuels are kerosene, jet fuel, diesel fuel, heating oil and heavy fuel oil. Heating oil can be a straight run atmospheric distillate, or it can also contain vacuum gas oil or cracked gas oil or both. The fuel can also contain a major or minor amount of components derived from the Fischer-Tropsch process. Fischer-Tropsch fuel, also referred to as FT fuel, includes those described as gas-to-liquid fuels, coal and / or biomass conversion fuels. In order to manufacture such fuels, synthesis gas (CO+H2) is first generated, which is then converted into normal paraffins and olefins by the Fischer-Tropsch process. The normal paraffins can then be modified by processes such as catalytic cracking / reforming or isomerization, hydrocracking and hydroisomerization to produce various hydrocarbons such as isoparaffins, cycloparaffins and aromatics. The resulting FT fuel can be used as is or in combination with other fuel components and fuel types such as those mentioned in this specification.

[0174] The present invention is also applicable to fuel oils containing fatty acid alkyl esters made from oils derived from animal or vegetable materials, commonly referred to as biofuels or biodiesel. Some believe that biofuels are less harmful to the environment when burned and are obtained from renewable sources. The present invention also includes other forms of biofuels, such as hydrogenated vegetable oils (HVO) and oils derived from alternative sources such as algae.

[0175] Suitable oils of animal or plant origin are rapeseed oil, canola oil, coriander oil, soybean oil, cottonseed oil, sunflower oil, castor oil, olive oil, peanut oil, corn oil, almond oil, palm kernel oil, coconut oil, mustard oil, jatropha oil, tallow and fish oil. Further examples include fuel oils derived from corn, jute, sesame, shea, peanut and linseed oil, and can be derived from them by methods known in the art. Rapeseed oil is a mixture of fatty acids esterified with glycerol moieties, which can be obtained in large quantities and can be obtained by squeezing in a simple manner by rapeseed. Regenerated oils, such as used kitchen oils are also suitable.

[0176] As alkyl esters of fatty acids, for example the following may be considered as commercial mixtures: ethyl, propyl, butyl, and especially methyl esters of fatty acids having 12 to 22 carbon atoms, such as lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, elaidic acid, petroselinic acid, ricinoleic acid, eleostearic acid, linoleic acid, linolenic acid, eicosanoic acid, gadoleic acid, behenic acid or erucic acid, having an iodine number of 50 to 150, in particular 90 to 125. Mixtures with particularly advantageous properties are those which contain predominantly, i.e. at least 50% by weight, methyl esters of fatty acids having 16 to 22 carbon atoms and 1, 2 or 3 double bonds. Preferred fatty acid alkyl esters are the methyl esters of oleic acid, linoleic acid, linolenic acid and erucic acid.

[0177] Commercial mixtures of the specified kind are obtained, for example, by cracking and esterification of animal and vegetable fats and oils by their transesterification with lower (approximately C1 to C6 aliphatic alcohols). For the production of fatty acid alkyl esters, it is advantageous to start with fats and oils with a low content of saturated acids of less than 20% and with an iodine value of less than 130. Blends of esters or oils are suitable, for example rapeseed, sunflower, canola, coriander, castor, soybean, peanut, cottonseed, tallow, etc. Fatty acid alkyl esters based on certain varieties of rapeseed oil with more than 80% by weight of unsaturated fatty acids containing 18 carbon atoms are particularly suitable.

[0178] Although all of the above biofuels can be used as fuel oil in the present invention, preferred are vegetable oil derivatives, wherein particularly preferred biofuels are alkyl ester derivatives of rapeseed oil, cottonseed oil, soybean oil, sunflower oil, olive oil or palm oil, and particularly preferred are rapeseed oil methyl esters. Such fatty acid methyl esters are generally referred to as FAME in the art.

[0179] Biofuels are usually used in combination with petroleum-derived fuel oils. The present invention is also applicable to mixtures of biofuels and petroleum-derived fuels in any ratio. Such fuels are usually referred to as "Bx" fuels, wherein x represents the weight percentage of the biofuel in the biofuel-petroleum blend. Examples include fuels wherein x is 2 or higher, preferably 5 or higher, for example up to 10, 25, 50 or 95. Current German regulations center on "B7" biofuels. Preferably, the biofuel component in such a Bx base fuel comprises fatty acid alkyl esters, most preferably fatty acid methyl esters.

[0180] The invention is also applicable to pure biofuels.Thus in one embodiment the fuel oil comprises substantially 100 wt% of a fuel derived from a plant or animal source, preferably substantially 100 wt% of fatty acid alkyl esters, most preferably fatty acid methyl esters.

[0181] Examples of jet fuels include fuels having a boiling point in the temperature range of about 65°C to about 330°C and sold under names such as JP-4, JP-5, JP-7, JP-8, Jet A, and Jet A-1. JP-4 and JP-5 are specified in US Military Specification MIL-T-5624-N, and JP-8 is specified in US Military Specification MIL-T-83133-D. Jet A, Jet A-1, and Jet B are specified in ASTM D1655.

[0182] The fuel oil, whether petroleum or plant or animal derived, or synthetic, has a low sulphur content. Typically, the sulphur content of the fuel is less than 1000 wppm (weight parts per million), such as less than 500 wppm. Preferably, the sulphur content of the fuel will be less than 100 wppm, for example less than 50 wppm, such as less than 20 wppm or less than 10 wppm.

[0183] In the untreated (i.e. without additives) state, such fuel oils generally have low conductivity, usually less than 10 pSm -1 , such as about 2-5pSm -1 .

[0184] In one embodiment, the preferred fuel oil comprises diesel fuel (which includes biodiesel fuel).

[0185] The amount of fuel oil additive added to the fuel oil will depend on the inherent conductivity of the fuel oil and the desired target conductivity to be achieved. However, preferably, the fuel oil additive is present in the fuel oil in an amount of between 5 and 1000 ppm by mass, preferably between 5 and 500 ppm by mass, more preferably between 5 and 200 ppm by mass, on an active ingredient basis, based on the total mass of the fuel oil composition.

[0186] As will be appreciated, the fuel oil additive may be added to the fuel oil in the form of the above-described additive composition (referred to as an additive concentrate). In this case, the amount of the additive composition used will relate to the active ingredient (ai) content of the fuel oil additive. For example, adding 200 mass ppm of a concentrate containing 20 wt % of a carrier liquid to a fuel oil will provide the fuel oil with 160 mass ppm of the fuel oil additive (A) on an active ingredient basis.

[0187] Suitably, the present invention provides the use of a fuel oil additive or an additive composition (concentrate) comprising a fuel oil additive in a middle distillate fuel oil having a sulphur content of 0.2 wt% or less.

[0188] Other additives commonly added to fuel oils may also be used together with the fuel oil additive (A). Such other additives may be introduced into the fuel oil separately, but may also be combined together in an additive concentrate as described above. The types of additives are known to those skilled in the art, and the following examples are not intended to constitute an exhaustive list.

[0189] One class is additives that can change the low temperature properties of fuel oil. Suitable materials are well known and include flow improvers such as ethylene-unsaturated ester copolymers and terpolymers, such as ethylene-vinyl acetate copolymers, ethylene-2-ethylhexanoic acid vinyl ester copolymers and ethylene-neodecanoic acid vinyl ester copolymers, ethylene-vinyl acetate-2-ethylhexanoic acid vinyl ester terpolymers, ethylene-vinyl acetate-neononanoic acid vinyl ester terpolymers, ethylene-vinyl acetate-neodecanoic acid vinyl ester terpolymers; comb polymers such as fumarate-vinyl acetate copolymers, polyacrylates and polymethacrylate polymers, including those containing nitrogen or copolymerized with nitrogen-containing monomers; hydrocarbon polymers such as hydrogenated polybutadiene copolymers, ethylene / 1-olefin copolymers and similar polymers. Additives known in the art such as wax anti-settling additives (WASA) are also suitable.

[0190] Other classes of additives are detergents and dispersants, typically of the hydrocarbyl-substituted succinimide variety; cetane improvers; metal-containing additives used to improve regeneration of particulate traps attached to the exhaust systems of some diesel engines; lubricity enhancers; other conductivity improvers; dyes and other markers; and antioxidants. The present invention contemplates the addition of these other additives; their use in terms of treat rates is known to those skilled in the art. In a preferred embodiment, the additive composition of the present invention is combined with, or used in conjunction with, one or both of an ethylene-unsaturated ester copolymer and a wax anti-settling additive. Particularly preferred ethylene-unsaturated ester copolymers are ethylene-vinyl acetate copolymers, ethylene-vinyl acetate-2-ethylhexanoate terpolymers, ethylene-vinyl acetate-neononanoate terpolymers, and ethylene-vinyl acetate-neononanoate terpolymers. Particularly preferred wax anti-settling additives are amide-amine salts formed by the reaction of phthalic anhydride with two molar proportions of di-hydrogenated tallowamine.

[0191] The invention will now be described by way of the following non-limiting examples.

[0192] Lubrication Performance Measurement Procedure

[0193] The lubricity of a fuel or fuel composition is measured using a ball-on-plate reciprocating friction and wear test system available from PCS Instruments Ltd of Stanley Gardens, London, according to ISO 12156 (Edition 2, 2018) using a High Frequency Reciprocating Rig (HFRR) test. Lubricity is reported as average wear scar depth (μm), where a reduced average wear scar indicates improved lubricity of the fuel.

[0194] Conductivity Performance Measurement Procedure

[0195] The electrical conductivity of the fuel or fuel composition is measured using an Emcee 1152 digital conductivity meter available from Emcee Electronics Inc. using Standard Test Method for Electrical Conductivity of Aviation and Distillate Fuels in accordance with ASTM D2624-22. The electrical conductivity properties are measured in picosiemens per meter (pSm -1 ) report.

[0196] Viscosity measurement procedure

[0197] The viscosity measurements of the additives at specific temperatures were measured using an Anton Paar SVM3001 viscometer with a temperature ramping programme. All measurements were performed with neat additive samples.

[0198] Diesel fuel and additives

[0199] Diesel fuel 1 Low sulfur Swedish Class diesel fuel with the following characteristics: Density 818kgm -3 ; K v (40℃)2.04cSt; K v (20°C) 3.07 cSt; cetane number 51.5; sulfur less than 0.0003% by weight.

[0200] Diesel fuel 2 Low sulfur commercial diesel fuel (Carcal) with the following characteristics: Density 832 kgm -3 ; K v (40℃)3.21cSt; Kv (20°C) 5.23 cSt; cetane number 55.5; sulfur less than 0.0034% by weight.

[0201] Additive A contains dimeric C 18 Known lubricity additives of diethylene glycol esters of oleic acid (US-A-3,287,273)

[0202] Additive B: Glyceryl neodecanoate additive synthesized according to Example 2

[0203] STADIS is available as a static dissipative additive Stadis 450 from Innospec Inc.

[0204] Example 1 Synthesis of Neodecanoyl Chloride

[0205] Neodecanoic acid (25 g, 0.145 mol) was cooled to 0°C and thionyl chloride (75 mL, 3 vols) and dimethylformamide (1.165 mL, 0.0145 mol) were added dropwise. The resulting reaction mixture was stirred at room temperature for 4 hours. After the reaction was complete, all volatiles were removed in vacuo on a rotary evaporator and co-evaporated with toluene (50 mL) to give the title compound, which was used directly in Example 2 without further purification.

[0206] Example 2 Synthesis of Glyceryl Neodecanoate (Additive B)

[0207] The title compound neodecanoyl chloride (0.145 mol) of Example 1 was added dropwise to a solution of solketal (18.7 g, 0.142 mol), triethylamine (88 g, 0.87 mol) and DMAP (1.77 g, 0.0145 mol) in anhydrous dichloromethane (125 ml) at 0°C, and the resulting reaction mixture was stirred at room temperature for 16 hours. After the reaction was complete (thin layer chromatography (TLC)), the reaction mixture was concentrated under reduced pressure to remove all volatiles, quenched with cold water, and then extracted with ethyl acetate (3 x 300 ml). The combined organic extracts were washed with water (2 x 500 ml), saline solution (500 ml), dried over sodium sulfate, filtered and concentrated under reduced pressure to obtain decanoic acid (2,2-dimethyl-1,3-dioxolan-4-yl) methyl ester.

[0208] A solution of (2,2-dimethyl-1,3-dioxolan-4-yl)methyl decanoate (42 g, 0.1955 mol) in 80% acetic acid (200 ml) was stirred at 80°C for 3 hours. The reaction mixture was concentrated under reduced pressure and co-evaporated with toluene (2X 150 ml). The crude product was purified by column chromatography (silica gel 230-400 mesh: 25-30% ethyl acetate in petroleum ether) to provide the title compound (26 g, 68%) as a light yellow liquid.

[0209] 1 H-NMR (400MHz, DMSO-d6): δ4.83 (br s, 1H), 4.62 (br s, 1H), 3.82-4.00 (m, 2H), 3.62-3.63 (m, 1H), 3.35-3.37 (m, 2H), 1.24 (m, 4H), 1.12 (m, 2H), 1.04-1.11 (m, 4H), 0.74-0.92 (m, 9H). Molecular formula: C 13 H 26 O4, molecular weight: 246.35, measured mass: 247.2 (M+1), by LCMS: MM-ES+APCI.

[0210] Example 3 Lubrication Performance

[0211] The lubricity performance of Additive A compared to Additive B was determined with Diesel Fuel 1 using the Lubricity Measurement Procedure described herein. The results are shown in Table 1.

[0212] Table 1

[0213]

[0214] The results in Table 1 demonstrate that Additive B is substantially as effective as commercial Additive A in improving the lubricity of low sulfur containing diesel fuels. Furthermore, Additive B exhibits improved performance compared to Additive A at dosage rates of 50 to 350 ppm (ai).

[0215] Example 4 Conductivity Performance of Additive B

[0216] The conductivity performance of Additive B (glyceryl neodecanoate) in Diesel Fuel 1 and Diesel Fuel 2 was determined using the conductivity performance measurement procedure described herein in the presence or absence of the static dissipative additive STADIS. Each experiment was repeated three times and the average conductivity measurement (pSm -1 ) are reported in Table 2.

[0217] Table 2

[0218]

[0219] The results in Table 2 demonstrate for Diesel Fuel 1 and Diesel Fuel 2:

[0220] • Addition of STADIS alone to each diesel fuel provided an improvement in the conductivity of the corresponding base fuel alone without the additive.

[0221] • The addition of Additive B alone to the respective diesel fuel generally does not significantly affect the conductivity of the corresponding base fuel alone without the additive.

[0222] • Addition of the combination of STADIS and Additive B to each diesel fuel provided an improvement in the conductivity of the base fuel alone that did not include the additives.

[0223] The improved conductivity of the respective diesel fuels including the combination of STADIS and Additive B is between the conductivity achieved by STADIS alone and Additive B alone, but is significantly higher than the 25 pSm specified by ASTM D975. -1 The required minimum conductivity limit.

[0224] Example 5 Conductivity performance of the combination of STADIS and Additive A or Additive B over time

[0225] The conductivity of diesel fuel 1 including an additive package comprising: (a) STADIS and Additive A; and (b) STADIS and Additive B was measured over a period of 28 days to determine what effect, if any, the presence of the respective additive (Additive A or B) had on the conductivity of the fuel with respect to time in the presence of a known static dissipative agent (i.e., STADIS). Each experiment was repeated three times and the average conductivity measurement (pSm) was taken as -1 ) are reported in Table 3.

[0226] Table 3

[0227]

[0228] The results in Table 3 demonstrate the following:

[0229] In the presence of STADIS alone, the conductivity of the fuel decreased over 28 days (i.e., the effectiveness of STADIS decreased over time). Furthermore, the relative decrease in fuel conductivity observed depended on the initial concentration of STADIS present in the fuel. When the fuel was treated with an initial STADIS concentration of 1 ppm, a 30% decrease in fuel relative conductivity over 28 days was observed, while a lower 18% decrease in fuel relative conductivity over 28 days was observed when the fuel was treated with a higher initial STADIS concentration of 3 ppm.

[0230] When Additive A is used in combination with STADIS, the presence of Additive A does not significantly affect the initial conductivity of the fuel after day 1, compared to a comparable fuel containing only STADIS. However, over time (e.g., after a period of 28 days), the presence of Additive A in combination with STADIS further significantly reduces the conductivity of the fuel compared to a comparable fuel containing only STADIS (i.e., the presence of Additive A has a significant negative impact on the effectiveness of STADIS over time). Furthermore, this significant negative impact of the presence of Additive A on the effectiveness of STADIS over time depends on the initial concentration of Additive A in the fuel. A higher initial concentration of Additive A in the fuel results in a greater decrease in the conductivity of the fuel over time (e.g., after 28 days), compared to a comparable fuel containing a lower initial concentration of Additive A. Therefore, when Additive A is used as a lubricity improver in combination with STADIS, it is often necessary to initially overtreat the fuel with increased amounts of the expensive STADIS additive in order to keep the conductivity of the fuel within the required specification limits after a specified period of time (e.g., after 28 days).

[0231] When Additive B is used in combination with STADIS, the presence of Additive B results in a relatively small reduction in the initial conductivity of the fuel after day 1, compared to a comparable fuel containing STADIS alone. However, over time (e.g., after a period of 28 days) and completely unexpectedly, when Additive B is used in combination with STADIS, the presence of Additive B substantially stabilizes the conductivity of the fuel, compared to a comparable fuel containing STADIS alone or a comparable fuel containing a combination of Additive A and STADIS. Thus, the use of Additive B in combination with STADIS not only enables the conductivity of the fuel to be improved compared to the untreated fuel alone, but also enables the conductivity of the treated fuel to be maintained at a substantially constant level over time (e.g., after 28 days). Suitably, this provides certainty to the fuel formulator and enables the formulator to provide a fuel having a desired and substantially stable conductivity specification without the need to overdose the fuel with a relatively high initial dose of the expensive STADIS additive.

[0232] Example 6 Viscosity Measurement of Additive A vs. Additive B

[0233] The viscosity of Additive B (glyceryl neodecanoate) and Known Additive A were measured at various temperatures using the viscosity measurement procedure described herein. The viscosity measurements (cSt) are reported in Table 4.

[0234] Table 4

[0235]

[0236]

[0237] The results in Table 4 demonstrate the following:

[0238] The viscosity of Additive B at each corresponding temperature point is significantly lower than that of Additive A.

[0239] The viscosity of Additive A increases significantly with a corresponding decrease in temperature. Additive A is still operable at 20°C. However, Additive A presents significant operability problems at temperatures below 20°C, especially below or equal to 10°C, due to the significant increase in the viscosity of Additive A. At 0°C, Additive A is too viscous to be measured.

[0240] Additive B has a much smaller increase in viscosity with a corresponding decrease in temperature than Additive A. Additive B is still operable at temperatures of 0°C and lower.

[0241] The viscosity of Additive B at 0°C is less than the viscosity of Additive A at 20°C, proving that Additive B is easier to handle (eg, pump, dispense, transport) at 0°C than Additive A at 20°C.

[0242] The lower viscosity of Additive B at low temperatures compared to Additive A means that Additive B is more suitable for use in cold climates than Additive A. Suitably, Additive B may be supplied in a pure form which is easier to transport and / or store and / or meter into the fuel in cold climates, particularly climates with low ambient temperatures of -5°C and below.

Claims

1. A fuel oil composition comprising a major amount of a middle distillate fuel oil having a sulfur content of 0.2 wt. % or less and a minor amount of a fuel oil additive, the fuel oil additive comprising: (a) an alkyl neo-monocarboxylic acid having a total of 5 to 30 carbon atoms and an aliphatic acyclic (C2 to C4) having a total of 2 to 18 carbon atoms and a total of 2 to 8 hydroxyl groups 18 ) ester of an alkanol, wherein the aliphatic acyclic (C2 to C 18 ) The alkanol comprises one or more alkyl chains, and each of the one or more alkyl chains may be optionally interrupted by one or more oxygen atoms.

2. The composition according to claim 1, wherein the aliphatic acyclic (C2 to C 18 ) The alkanol is represented by a compound of formula I: in: R1 represents an aliphatic acyclic alkyl chain having a total of 1 to 17 carbon atoms, which is optionally interrupted by one or more oxygen atoms; (CH2OH) m represents a primary hydroxyl functional group and m is an integer from 1 to 3; (CH2OH) n represents a primary hydroxyl functional group and n is an integer from 0 to 3; and (OH) s represents a secondary hydroxyl functional group and s is an integer from 0 to 6; and the sum of m, n and s is an integer from 2 to 8.

3. The composition according to claim 2, wherein the aliphatic acyclic (C2 to C 18 ) The alkanol contains only primary hydroxyl functional groups, and m and n in the compound of Formula I are each independently an integer from 1 to 3, and s is 0.

4. The composition according to claim 3, wherein the aliphatic acyclic (C2 to C 18 ) The alkanol is selected from ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolpropane and di-trimethylolpropane.

5. The composition according to claim 2, wherein the aliphatic acyclic (C2 to C 18 )The alkanol contains one or more secondary hydroxyl groups and one or more primary hydroxyl functional groups, and s in the compound of formula I is an integer from 1 to 6, m in the compound of formula I is an integer from 1 to 3, and n in the compound of formula I is an integer from 0 to 3.

6. The composition according to claim 5, wherein m and n in the compound of formula I each represent 1, s is an integer from 1 to 3, and the total number of hydroxyl functional groups present in the compound of formula I is from 3 to 6.

7. The composition according to any one of claims 3 to 5, wherein R 1 represents an aliphatic acyclic alkyl straight chain having a total number of 1 to 16, preferably 1 to 12, more preferably 1 to 10, still more preferably 1 to 8, still more preferably 1 to 6, still more preferably 1 to 4 carbon atoms.

8. The composition according to any one of claims 3 to 7, wherein R 1 The aliphatic acyclic alkyl chains represented are not interrupted by one or more oxygen atoms.

9. The composition according to claim 2, wherein the aliphatic acyclic (C2 to C 18 ) The alkanol is selected from glycerol, diglycerol, triglycerol and hexaglycerol.

10. The composition according to claim 9, wherein the aliphatic acyclic (C2 to C 18 )Alkanols include glycerol.

11. A composition according to any one of the preceding claims, wherein the alkyl neo-monocarboxylic acid is represented by a compound of formula II: in: R 2 represents hydrogen or C1 to C 18 Alkyl, R 3 and R 4 Each independently represents C1 to C 18 Alkyl, and R 2 , R 3 and R 4 The total number of carbon atoms together ranges from 3 to 28.

12. The composition according to claim 11, wherein R 2 C1 to C 18 alkyl.

13. The composition according to any one of claims 11 or 12, wherein R 2 , R 3 and R 4 Each occurrence independently represents a linear or branched acyclic C1 to C 12 , more preferably C1 to C 10 , still more preferably C1 to C8, still more preferably C1 to C6 alkyl.

14. The composition according to any one of claims 11 to 13, wherein R 2 , R 3 and R 4 At least one of represents a branched-chain alkyl group.

15. The composition according to any one of claims 11 to 14, wherein R 2 , R 3 and R 4 The total number of carbon atoms together is 3 to 8.

16. The composition according to any one of claims 11 to 15, wherein the alkyl neo-monocarboxylic acid comprises one or more neodecanoic acids, and R 2 , R 3 and R 4 The total number of carbon atoms together is 8.

17. A composition according to any one of the preceding claims, wherein the fuel oil additive (A) comprises a compound of formula IIIA, IIIB, IIIC, IIID or IIIE, preferably a compound of formula IIIA or IIIB, wherein R 2 , R 3 and R 4 Each as defined in any one of claims 11 to 16 for a compound of formula II:

18. The composition according to any one of the preceding claims, wherein the fuel oil additive (A) is present in an amount of less than 1000 ppm by mass, based on the total mass of the fuel oil composition.

19. The composition according to any one of the preceding claims, further comprising an antistatic additive (B) present in a minor amount, preferably in an amount less than or equal to 10 ppm by mass, based on the total mass of the fuel oil composition.

20. The composition of claim 19, wherein the antistatic additive (B) comprises a two-component mixture of a reaction product of a polysulfone and a polymeric polyamine.

21. Method for using a fuel oil additive (A) as defined in any one of claims 1 to 20, wherein the fuel oil additive (A) is used as an additive in an effective minor amount in a middle distillate fuel oil having a sulfur content of less than or equal to 0.2% by weight, based on the total weight of the middle distillate fuel oil, for enhancing the lubricity properties of the middle distillate fuel oil.

22. Method for using a fuel oil additive (A) as defined in any one of claims 1 to 20, wherein the fuel oil additive (A) and the antistatic additive (B) according to claim 18 or 19 are used as an additive combination in an effective minor amount in a middle distillate fuel oil having a sulfur content of less than or equal to 0.2% by weight, based on the total weight of the middle distillate fuel oil, for increasing the electrical conductivity of the middle distillate fuel oil and maintaining the electrical conductivity of the middle distillate fuel at a substantially constant level over a long period of time.

23. A method for using a fuel oil additive (A) as defined in any one of claims 1 to 20, wherein the fuel oil additive (A) is used as an additive in an effective minor amount in a middle distillate fuel oil having a sulfur content of less than or equal to 0.2% by weight, based on the total weight of the middle distillate fuel oil, for reducing the wear rate in a fuel supply system of a combustion device using the middle distillate fuel oil.

24. A fuel additive composition for a middle distillate fuel oil having a sulfur content of 0.2 wt% or less, comprising a fuel additive (A), wherein the fuel additive (A) is a compound represented by formula IIIA, IIIB, IIIC, IIID or IIIE as defined in claim 17, preferably a compound represented by formula IIIA or IIIB.

25. The fuel additive composition of claim 24, wherein the composition further comprises a minor amount of an inert organic solvent, and wherein the fuel additive (A) is present in a major amount of the composition.

26. The fuel additive composition according to any one of claims 24 or 25, wherein the fuel additive (A) has a viscosity less than or equal to 10000 cSt when measured at 0°C.

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