阅读说明：本技术 制备燃料添加剂的方法 (Method for preparing fuel additive ) 是由 V·亨斯托克 B·希尔 S·V·菲利普 于 2018-12-19 设计创作，主要内容包括：提供了一种制备燃料添加剂f的优化方法。该方法包括进行以下反应：(c,d,e)<Image he="395" wi="553" file="775692DEST_PATH_IMAGE001.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>。起始原料c可以使用一种优化的方法制备,该方法包括进行以下反应：(a,b,c)<Image he="199" wi="528" file="692833DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>。(An optimized process for the preparation of the fuel additive f is provided. The method comprises the following reaction: (c, d, e) . The starting material c can be prepared using an optimized process which comprises carrying out the following reaction: (a, b, c) 。)

1. A method of making a fuel additive having the formula:

wherein: r₁Is hydrogen;

R₂、R₃、R₄、R₅、R₁₁and R₁₂Each independently selected from hydrogen, alkyl, alkoxy-alkyl, secondary amine, and tertiary amine groups;

R₆、R₇、R₈and R₉Each independently selected from hydrogen, alkyl, alkoxy-alkyl, secondary amine, and tertiary amine groups;

x is selected from-O-or-NR₁₀-, wherein R₁₀Selected from hydrogen and alkyl; and

n is a number of 0 or 1,

the method comprises carrying out the following reaction:

wherein: r₁₃Selected from alkyl and aryl; and

each L is independently selected from a leaving group, and

wherein step (ii) is carried out in the presence of a base selected from the group consisting of alkali metal hydroxides and alkali metal carbonates, and wherein starting materials are reacted withcIn contrast, the base is used in an amount of at least 2 molar equivalents.

2. The process according to claim 1, wherein the alkali metal hydroxide is selected from sodium hydroxide and potassium hydroxide, and preferably sodium hydroxide, and wherein the alkali metal carbonate is selected from sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and cesium carbonate, and preferably cesium carbonate.

3. The process according to claim 1 or 2, wherein the base is selected from alkali metal hydroxides.

4. A process according to any one of claims 1 to 3, wherein the starting material is reacted withcIn contrast, the amount of the base used is 2 to 12 molar equivalents, preferably 3 to 10 molar equivalents, and more preferably 4 to 8 molar equivalents.

5. The process according to any one of claims 1 to 4, wherein the base is added to the starting material in at least two portionscAnd preferably wherein the total amount of base added in each portion is no more than 70%, preferably no more than 60%, and more preferably no more than 50%.

6. Process according to any one of claims 1 to 5, wherein starting materials are reacted withcComparative reagentsdIs used in an amount of 1 to 20 molar equivalents, preferably 2 to 15 molar equivalents, and more preferably 4 to 10 molar equivalents.

7. The process according to any one of claims 1 to 6, wherein step (ii) is carried out in the presence of a solvent selected from the group consisting of methyl isobutyl ketone and acetonitrile, and preferably in the presence of acetonitrile.

8. The process according to any one of claims 1 to 7, wherein step (ii) is carried out in the presence of a catalyst, preferably tetrabutylammonium halide, and more preferably tetrabutylammonium bromide.

9. The process according to any of claims 1 to 8, wherein step (iii) is carried out in an aqueous solution, preferably comprising a base, such as sodium hydroxide.

10. The method according to any one of claims 1 to 9, wherein R₁₃Selected from methyl, ethyl and phenyl, and more preferably R₁₃Is phenyl.

11. The method according to any one of claims 1-10, wherein each L is independently selected from: halogen (e.g., Cl, Br, I), substituted aryloxy (e.g., -O-Ar wherein Ar is selected from nitro substituted aryl such as p-nitrophenyl), and sulfonate (e.g., -OSO)₂A, wherein A is selected from tolyl, methyl, -CF₃、-CH₂Cl, phenyl and p-nitrophenyl), preferably from halogen, and more preferably from Cl and Br.

12. A process for preparing a starting material for use in any one of claims 1 to 11cThe method of (a), comprising performing the following reaction:

wherein: l' is a leaving group, and

wherein step (i) is carried out in the presence of a solvent system comprising a primary solvent selected from tetrahydrofuran and dichloromethane.

13. The process according to claim 12, wherein the solvent system comprises at least 30% by volume, and preferably at least 40% by volume of the primary solvent.

14. A process according to claim 12 or claim 13, wherein the solvent system further comprises water, preferably in an amount of at least 30% by volume, and more preferably at least 40% by volume.

15. The process according to any one of claims 12 to 14, wherein at least 90%, preferably at least 95%, and more preferably at least 99% by volume of the solvent system consists of the main solvent and, if present, water.

16. The process according to any one of claims 12 to 15, wherein the primary solvent is dichloromethane.

17. A process according to any one of claims 12 to 16, wherein the solvent system is used in an amount of from 5 to 15 ml/g of reagentaPreferably 6 to 10 mg/g of reagentaAnd more preferably 6.5 to 8.5 ml/g of reagenta。

18. The method according to any one of claims 12 to 17, wherein the agent is admixed withaComparative reagentsbIs used in an amount of 1 to 1.05 molar equivalents, preferably 1.0005 to 1.01 molar equivalents, and more preferably 1.001 to 1.005 molar equivalents.

19. The process according to any one of claims 12 to 18, wherein step (i) is carried out in the presence of a base, preferably a carbonate base, more preferably selected from the group consisting of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and cesium carbonate, and still more preferably sodium bicarbonate.

20. The process according to any one of claims 1 to 11, wherein the starting materialcPrepared by a process as defined in any one of claims 12 to 19.

21. The method according to any one of claims 1-11 and 20, wherein the method is a batch process, wherein the fuel additive is produced in batches of more than 100 kg, preferably more than 150 kg, and more preferably more than 200 kg.

22. The process according to any one of claims 1-11 and 20, wherein the process is a continuous process.

23. The process according to any one of claims 1 to 22, wherein steps (i), (ii) and (iii) are carried out in a reactor having a capacity of at least 500L, preferably at least 750L, and more preferably at least 1000L.

24. A fuel additive having the formula:

wherein: r₁Is hydrogen;

R₂、R₃、R₄、R₅、R₁₁and R₁₂Each independently selected from hydrogen, alkyl, alkoxy-alkyl, secondary amine, and tertiary amine groups;

R₆、R₇、R₈and R₉Each independently selected from hydrogen, alkyl, alkoxy-alkyl, secondary amine, and tertiary amine groups;

x is selected from-O-or-NR₁₀-, wherein R₁₀Selected from hydrogen and alkyl; and

n is a number of 0 or 1,

wherein the fuel additive is obtainable by a process according to any one of claims 1 to 23.

25. A method of making a fuel for a spark-ignited internal combustion engine, the method comprising:

preparing a fuel additive using the method of any one of claims 1-11 and 20-23; and

the fuel additive is blended with a base fuel.

26. A fuel for a spark-ignition internal combustion engine, the fuel comprising a fuel additive according to claim 24 and a base fuel.

Technical Field

The present invention relates to a method of preparing an octane boosting additive for a fuel for a spark-ignition internal combustion engine. In particular, the present invention relates to a method for preparing an octane boosting fuel additive which is benzo [1,4] oxazine and 1, 5-benzoazepine derivative. The invention also relates to a method of preparing a fuel for a spark-ignition internal combustion engine comprising the fuel additive.

Background

Spark ignition internal combustion engines are widely used for power in homes and industries. For example, spark ignition internal combustion engines are commonly used in the automotive industry to power vehicles such as passenger cars.

Fuels for spark-ignited internal combustion engines, typically gasoline fuels, typically contain a number of additives to improve the properties of the fuel.

One class of fuel additives is octane improving additives. These additives increase the octane number of the fuel, which is desirable to address pre-ignition related issues such as knock (knock). The addition of the fuel with octane improvers may be performed by a refinery or other supplier, such as a fuel terminal or a bulk fuel blender, to bring the fuel to an applicable fuel specification when the base fuel octane would otherwise be too low.

Organometallic compounds, including for example iron, lead or manganese, are well known octane improvers, of which tetraethyl lead (TEL) has been widely used as a highly effective octane improver. However, TEL and other organometallic compounds are now commonly used in fuels in only small amounts (if any) because they can be toxic, harmful to engines, and harmful to the environment.

Octane improvers that are not metal-based include oxygenates (e.g., ethers and alcohols) and aromatic amines. However, these additives also have various disadvantages. For example, N-methylaniline (NMA), an aromatic amine, must be used at relatively high treat rates (1.5-2% additive by weight per weight of base fuel) to have a significant impact on the octane number of the fuel. NMA may also be toxic. Oxygenates reduce the energy density in the fuel and, like NMA, must be added at higher treat rates, which can lead to compatibility issues with fuel storage, fuel piping, seals and other engine components.

Recently, a new class of octane boosting additives has been discovered. These octane boosting additives are derivatives of benzo [1,4] oxazine and 1, 5-benzoazepine and show great promise due to their non-metallic nature, their low oxygen containing compound content and their efficacy at low processing rates (see WO 2017/137518).

The synthetic routes currently reported in the literature provide various descriptions of how benzoxazines can be prepared on a relatively small scale (hundreds of mg up to 100 kg scale). For example, US 2008/064871-which relates to compounds for the treatment or prevention of uric acid related diseases (such as gout) -discloses the preparation of benzoxazine-derived compounds. Synthetic routes are also found in Hernandez-Olmos et al: n-substituted phenoxazine and acridone derivatives: the Structure-activity relationship of Potent P2X4 Receptor Antagonists (N-secreted Phenoxazine and Acridone Derivatives: Structure-activity relationships of patent P2X4 receptors) (J. Med. Chem, 2012, 55(22), 9576-factor 9588).

However, there is a need for a process suitable for producing this new class of octane boosting additives on an industrial scale (e.g. in an amount of 50-20,000 tons per year). For production on this scale, any synthetic method to be optimized is very convenient. This is especially the case when relatively expensive starting materials such as aminophenols are used in the process.

Therefore, there is a need for an optimized process for the synthesis of a new class of octane boosting additives, which is preferably suitable for implementation on a large scale.

Summary of The Invention

Preparation method

The present invention provides a method for preparing a fuel additive having the formulafThe method of (1):

wherein: r₁Is hydrogen;

R₂、R₃、R₄、R₅、R₁₁and R₁₂Each independently selected from hydrogen, alkyl, alkoxy-alkyl, secondary amine, and tertiary amine groups;

R₆、R₇、R₈and R₉Each independently selected from hydrogen, alkyl, alkoxy-alkyl, secondary amine, and tertiary amine groups;

x is selected from-O-or-NR₁₀-, wherein R₁₀Selected from hydrogen and alkyl; and

n is 0 or 1.

The method comprises the following reaction:

wherein: r₁₃Selected from alkyl and aryl; and

each L is independently selected from a leaving group, and

wherein step (ii) is carried out in the presence of a base selected from the group consisting of alkali metal hydroxides and alkali metal carbonates, and wherein starting materials are reacted withcIn contrast, the base is used in an amount of at least 2 molar equivalents.

The invention also provides a preparation method of the starting materialcThe method of (a), comprising performing the following reaction:

wherein: l' is a leaving group, and

wherein step (i) is carried out in the presence of a solvent system comprising a primary solvent selected from tetrahydrofuran and dichloromethane.

Fuel additives obtainable by the process of the inventionfIs also provided.

The invention further provides a process for preparing a fuel for a spark-ignition internal combustion engine, which process comprises admixing an additive composition (package) of the inventionComprisesf) Blended with a base fuel. Accordingly, the method may comprise:

the method of the invention is adopted to prepare the fuel additivef(ii) a And

the fuel additive is blended with a base fuel.

Fuel for a spark ignition internal combustion engine is also provided. The fuel comprises the fuel additive of the inventionfAnd a base fuel.

Detailed Description

The invention provides a fuel additivefAnd for preparing fuel additivesfStarting material for the process of (1)cThe method of (1).

Starting materialscPrepared by a process comprising performing the following reaction:

。

step (i) of the process is carried out in the presence of a solvent system comprising a primary solvent selected from tetrahydrofuran and dichloromethane. These solvents are preferred because their use results in starting materials with high yield and good puritycThe production of (1). Dichloromethane is particularly preferred as solvent, giving starting materials with high purityc。

The solvent system preferably comprises at least 30%, and preferably at least 40% by volume of the primary solvent.

In a preferred embodiment, the solvent system further comprises water, preferably in an amount of at least 30%, and more preferably at least 40% by volume.

Generally, at least 90%, preferably at least 95%, and more preferably at least 99% by volume of the solvent system consists of the principal solvent and water (where present).

The solvent system may be 5-15 ml/g, preferably 6-10 mg/g, and more preferably 6.5-8.5 ml/g of reagentaThe amount of (c) is used.

With reagentsaComparative reagentsbIn step (i) in a molar equivalent of from 1 to 1.05, preferably from 1.0005 to 1.01, and more preferably from 1.001 to 1.005 molar equivalents are used.

Step (i) is preferably carried out in the presence of a base, and more preferably a carbonate base. The carbonate base is preferably an alkali metal carbonate and may be selected from sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and cesium carbonate, and still more preferably is sodium bicarbonate.

With reagentsaIn contrast, the base is preferably used in step (i) in an amount of 0.8 to 2 molar equivalents, preferably 1 to 1.5 molar equivalents, and more preferably 1.05 to 1.2 molar equivalents.

Step (i) may conveniently be carried out at room temperature (e.g. at a temperature of from 15 to 30 ℃, preferably from 20 to 25 ℃) or with cooling (e.g. to a temperature of from 5 to 15 ℃).

Step (i) is preferably carried out at ambient pressure, i.e. a pressure of about 1 bar.

The reaction is preferably carried out for at least 30 minutes, preferably at least 1 hour, and more preferably at least 4 hours.

ReagentbContaining a leaving group L'. Such groups are preferably selected from: halogen (e.g., Cl, Br, I), substituted aryloxy (e.g., -O-Ar wherein Ar is selected from nitro substituted aryl such as p-nitrophenyl), and sulfonate (e.g., -OSO)₂A, wherein A is selected from tolyl, methyl, -CF₃、-CH₂Cl, phenyl and p-nitrophenyl), more preferably from halogen, and still more preferably from Cl and Br.

ReagentbAlso containing substituents R₁₃. Such groups are selected from alkyl and aryl groups. R₁₃Preferably selected from methyl, ethyl and phenyl. More preferably, R₁₃Is phenyl. This is because in step (iii) of the process the phenyl substituents are more easily removed and can be easily reacted with the product as an oil by washing with waterfAnd (5) separating.

The process of the present invention can be used to prepare starting materials in yields of greater than 85%, more preferably greater than 90%, and still more preferably greater than 95%c. As is conventional in the art, the yield (as with all yields mentioned herein) is calculated from the amount of product experimentally produced compared to the theoretical amount of product expected based on the stoichiometry of the reaction.

The inventionCan be used to prepare the starting material in a form having a purity of greater than 97%, preferably greater than 98%, and more preferably greater than 99% by weightc. Purity can be measured by LCMS, assuming the starting material in the chromatogramcThe ratio of peak area to total peak area is equal to the weight ratio. LCMS can be performed using the conditions detailed in the examples.

Once the starting material is preparedcIt can be used for preparing octane number raising fuel additivefIn the method of (1).

Preparation of octane number enhancing fuel additivefThe method comprises two steps: steps (ii) and (iii). In step (ii) of the process, formation of an intermediate is carried outeThe ring-closure reaction of (1):

despite the starting materialscPreferably prepared by the process of the invention, but it may also be obtained by other methods.

Step (ii) of the process is carried out in the presence of a base selected from alkali metal hydroxides and alkali metal carbonates. The use of these bases facilitates intermediateseIs performed.

The use of alkali metal hydroxides is particularly preferred. The alkali metal hydroxide may be selected from sodium hydroxide and potassium hydroxide. Sodium hydroxide is particularly preferred.

The carbonate base may be selected from sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and cesium carbonate. Cesium carbonate is preferred.

Sodium hydroxide and cesium carbonate are particularly preferred because they reduce the formation of the following dimer by-products:

。

with starting materialscIn contrast, the base is used in step (ii) in an amount of at least 2 molar equivalents. Preferably, with the starting materialscIn contrast, the amount of the base used is 2 to 12 molar equivalents, preferably 3 to 10 molar equivalents, and more preferably 4 to 8 molar equivalents.

In some embodiments, particularly where the base is an alkali metal hydroxide, the base is added to the starting material in at least 2 parts, for example in 2 or 3 parts, and preferably in 2 partscIn (1). Preferably, not more than 70%, more preferably not more than 60%, and still more preferably not more than 55% of the total amount of base used is added to the starting material in each portioncIn (1).

The time interval between addition of the portions may be at least 1 hour, preferably at least 2 hours, and more preferably at least 3 hours. Typically the time interval will be less than 6 hours.

Each portion may be added dropwise (e.g., over a period of from 15 minutes to 1 hour), although it is generally preferred to add each portion at once. It will be appreciated that when each portion of base is added dropwise, the time interval between the addition of each portion is taken as the time interval between the first drops added from each portion.

With starting materialscComparative reagentsdPreferably in an amount of 1 to 20 molar equivalents, preferably 2 to 15 molar equivalents, and more preferably 4 to 10 molar equivalents, are used in step (ii).

Step (ii) is preferably carried out in the presence of a solvent selected from methyl isobutyl ketone and acetonitrile. Acetonitrile is particularly preferred.

Preferably, the solvent is used in an amount of at least 10 ml/1 g of starting materialcThe amount of (c) is used.

In some embodiments, step (ii) is carried out in the presence of a catalyst, preferably a tetrabutylammonium halide, and more preferably tetrabutylammonium bromide.

With starting materialscIn contrast, the catalyst may be used in an amount of less than 1 molar equivalent, preferably less than 0.5 molar equivalent, and more preferably less than 0.1 molar equivalent.

Step (ii) may be carried out at a temperature of from 10 to 150 ℃.

When the base used in step (ii) is an alkali metal carbonate, the reaction is preferably carried out at elevated temperature, for example at a temperature of at least 30 ℃, preferably at least 50 ℃ and more preferably at least 60 ℃. In some embodiments, the reaction in step (ii) may be carried out under reflux. Elevated temperatures are preferred to reduce the formation of by-products.

When the base used in step (ii) is an alkali metal hydroxide, the reaction is preferably carried out at a temperature of from 15 to 40 ℃, preferably from 20 to 35 ℃ and more preferably from 22 to 30 ℃.

The reaction in step (ii) may be carried out for at least 12 hours, and preferably at least 15 hours.

Step (ii) is preferably carried out at ambient pressure, i.e. a pressure of about 1 bar.

In a preferred embodiment, step (ii) is carried out as a single reaction (i.e. using one set of reagents and under one set of conditions). However, in some embodiments, step (ii) comprises the following sub-steps:

it will be appreciated that in some cases step (iib) will occur spontaneously upon formation of the alkylated phenol intermediate. For the purposes of the present invention, these cases are considered to be embodiments in which step (ii) is carried out as a single reaction.

The conditions for step (iia) are preferably as described above for step (ii). However, when the closed loop does not spontaneously occur in step (iib), step (iib) may be performed using different conditions.

For example, step (iib) may be carried out in the presence of a base, for example a base selected from alkali metal hydrides (such as sodium hydride), carbonates (such as alkali metal carbonates, for example sodium carbonate, sodium bicarbonate, potassium carbonate and potassium bicarbonate) and alkali metal alkoxides (such as alkali metal tert-butoxide, for example sodium tert-butoxide or potassium tert-butoxide).

The solvent used in step (iib) may be selected from aprotic solvents such as tetrahydrofuran, acetonitrile, dimethoxyethane, dioxane, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, ethylene carbonate, sulfolane, diphenyl ether, acetonitrile, 2-nitropropane, acetone, butan-2-one, butyl formate, ethyl acetate, isobutyronitrile, methyl acetate, methyl formate, nitromethane, oxolane and propionitrile, and is preferably selected from dimethylformamide, N-methyl-2-pyrrolidone, dimethylacetamide, dimethylsulfoxide and sulfolane. Aprotic solvents are well known in the art as solvents that do not provide protons. The aprotic solvent does not contain a hydrogen atom bonded to nitrogen or oxygen.

In step (ii), the leaving group L is removed from the reagentdIs lost. Preferably, each L is independently selected from: halogen (e.g., Cl, Br, I), substituted aryloxy (e.g., -O-Ar wherein Ar is selected from nitro substituted aryl such as p-nitrophenyl), and sulfonate (e.g., -OSO)₂A, wherein A is selected from tolyl, methyl, -CF₃、-CH₂Cl, phenyl and p-nitrophenyl), more preferably from halogen, and still more preferably from Cl and Br.

Preferably, at least one and more preferably each L is Br. Especially where the base is an alkali metal hydroxide. If each L is Cl, step (ii) is preferably carried out in the presence of a catalyst, for example tetrabutylammonium halide as described above.

The process of the present invention can be used to prepare intermediates in yields greater than 60%, more preferably greater than 70%, and more preferably greater than 80%e。

The process of the invention can be used to prepare intermediates in a form having a purity of greater than 80%, preferably greater than 85%, and more preferably greater than 90% by weighte. Purity can be measured by LCMS, assuming intermediates in the chromatogrameThe ratio of peak area to total peak area is equal to the weight ratio.

Dimer by-products may be less than 20%, preferably less than 15%, and more preferably less than 10% by weight of the intermediateeThe amount of (c) is formed. The% weight of dimer by-product can be measured using LCMS, where the peak area of the dimer by-product in the chromatogram is assumed to be related to the intermediateeThe ratio of peak area to total peak area is equal to the weight ratio.

As described above, LCMS can be performed using the conditions detailed in the examples.

In step (iii) of the process, intermediateseIs deprotected to form a productf：

。

Conventional deprotection methods may be employed. However, in a preferred embodiment, step (iii) is preferably carried out in an aqueous solution, preferably comprising an acid or a base, and more preferably a base.

The base is preferably selected from inorganic bases, for example from alkali metal bases, preferably from alkali metal hydroxides, and more preferably sodium hydroxide.

And intermediateseIn contrast, the base is preferably used in step (iii) in molar excess. For example, the base may be an intermediateeIs used in an amount of at least 2 times, and preferably at least 3 times the molar amount of (c). This is believed to aid in the removal of dimer by-products.

The acid is preferably selected from mineral acids, and more preferably is hydrochloric acid.

Step (iii) may be carried out at elevated temperature, for example at a temperature of at least 30 ℃, preferably at least 50 ℃ and more preferably at least 60 ℃. In some embodiments, the reaction in step (iii) may be carried out under reflux.

The reaction in step (iii) may be carried out for at least 12 hours, and preferably at least 15 hours.

Step (iii) is preferably carried out at ambient pressure, i.e. a pressure of about 1 bar.

In a very particular embodiment, step (i) is carried out in the presence of a base (such as sodium bicarbonate) and a solvent (such as dichloromethane). Step (ii) is carried out in the presence of a base (such as sodium hydroxide) and a solvent (such as acetonitrile) and step (iii) is carried out in the presence of an aqueous base (such as sodium hydroxide).

The process of the invention is preferably carried out on an industrial scale. For example, when preparing fuel additivesfWhen the process of (a) is a batch process, the fuel additive is preferably produced in batches of greater than 100 kg, preferably greater than 150 kg, and more preferably greater than 200 kg. The process may also be carried out as a continuous process.

In order to produce the fuel additive on an industrial scale, steps (i), (ii) and (iii) are preferably carried out in a reactor having a capacity of at least 500L, preferably at least 750L, and more preferably at least 1000L. It will be appreciated that more than one (e.g. each) step may be carried out in the same reactor.

Octane number enhancing additivef

Fuel additives prepared by the process of the inventionfHaving the formula:

wherein: r₁Is hydrogen;

R₂、R₃、R₄、R₅、R₁₁and R₁₂Each independently selected from hydrogen, alkyl, alkoxy-alkyl, secondary amine, and tertiary amine groups;

R₆、R₇、R₈and R₉Each independently selected from hydrogen, alkyl, alkoxy-alkyl, secondary amine, and tertiary amine groups;

x is selected from-O-or-NR₁₀-, wherein R₁₀Selected from hydrogen and alkyl; and

n is 0 or 1.

Additive for fuelfPreferred substituents of (a) are described below. It will be appreciated that the preferred substitution patterns also apply to the starting materialscAnd preparing the starting materials therefromcOf (2)aAndband preparation of fuel additives therefromfOf (2)dAnd intermediatese。

In some embodiments, R₂、R₃、R₄、R₅、R₁₁And R₁₂Each independently selected from hydrogen and alkyl, and preferably from hydrogen, methyl, ethyl, propyl and butyl. More preferably, R₂、R₃、R₄、R₅、R₁₁And R₁₂Each independently selected from hydrogen, methyl and ethyl, and even more preferably from hydrogen and methyl.

In some embodiments, R₆、R₇、R₈And R₉Each independently selected from hydrogen, alkyl and alkoxy, and preferably from hydrogen, methyl, ethyl, propyl, butyl, and alkoxy,Methoxy, ethoxy and propoxy. More preferably, R₆、R₇、R₈And R₉Each independently selected from hydrogen, methyl, ethyl and methoxy, and even more preferably from hydrogen, methyl and methoxy.

Advantageously, R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂And preferably R₆、R₇、R₈And R₉At least one selected from the group consisting of groups other than hydrogen. More preferably, R₇And R₈At least one selected from the group consisting of groups other than hydrogen. Alternatively, the fuel additive may consist of R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂At least one position, preferably in the group consisting of R₆、R₇、R₈And R₉At least one position represented by R, and more preferably at a position represented by R₇And R₈In at least one position of the representation, is substituted. It is believed that the presence of at least one group other than hydrogen can enhance octane boosting fuel additivesfSolubility in fuel.

Also advantageously, R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂No more than 5, preferably no more than 3, and more preferably no more than 2 groups selected from groups other than hydrogen. Preferably, R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂One or both of which are selected from groups other than hydrogen. In some embodiments, R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂Only one of which is selected from groups other than hydrogen.

R₂And R₃In (1)It is also preferred that at least one is hydrogen, and more preferably R₂And R₃Are both hydrogen.

In a preferred embodiment, R₄、R₅、R₇And R₈At least one of which is selected from methyl, ethyl, propyl and butyl, and the remainder of R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂Is hydrogen. More preferably, R₇And R₈At least one of which is selected from methyl, ethyl, propyl and butyl, and the remainder of R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂Is hydrogen.

In a further preferred embodiment, R₄、R₅、R₇And R₈At least one of which is methyl and the remainder of R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂Is hydrogen. More preferably, R₇And R₈At least one of which is methyl and the remainder of R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉、R₁₁And R₁₂Is hydrogen.

Preferably, X is-O-or-NR₁₀-, wherein R₁₀Selected from hydrogen, methyl, ethyl, propyl and butyl, and preferably from hydrogen, methyl and ethyl. More preferably, R₁₀Is hydrogen. In a preferred embodiment, X is-O-.

n may be 0 or 1, although preferably n is 0.

Octane boosting fuel additives useful in the present invention include:

。

preferred octane boosting additives include:

。

the following octane boosting additives are particularly preferred:

。

fuel additivefThe mixture of (a) can be used in a fuel composition. For example, the fuel composition may comprise a mixture of:

。

it will be appreciated that reference to alkyl groups includes the different isomers of the alkyl groups. For example, reference to propyl encompasses n-propyl and isopropyl, and reference to butyl encompasses n-butyl, isobutyl, sec-butyl and tert-butyl.

Additive and fuel composition

The present invention provides a fuel additive obtainable by the process according to the inventionf. Preferably, the fuel additive is obtained by the method according to the invention.

The present invention also provides a method of preparing a fuel for a spark-ignition internal combustion engine, the method comprising:

the method of the invention is adopted to prepare the fuel additivef(ii) a And

the fuel additive is blended with a base fuel.

Fuel for a spark ignition internal combustion engine is also provided. The fuel comprises: fuel additive obtainable by the process according to the invention and preferably obtained therefromfAnd a base fuel.

Gasoline fuels, including those containing oxygenates, are commonly used in spark-ignition internal combustion engines. Accordingly, the fuel composition that may be prepared according to the process of the present invention may be a gasoline fuel composition.

The fuel composition may comprise a major amount (i.e. greater than 50% by weight) of a liquid fuel ("base fuel") and a minor amount (i.e. less than 50% by weight) of an additive composition of the invention. Examples of suitable liquid fuels include hydrocarbon fuels, oxygenated fuels, and combinations thereof.

The fuel composition may contain an octane boosting fuel additive in an amount up to 20%, preferably from 0.1% to 10%, and more preferably from 0.2% to 5% by weight additive per weight base fuelf. Even more preferably, the fuel composition contains the fuel additive in an amount of 0.25% to 2%, and even more preferably still 0.3% to 1% additive by weight per weight of base fuel. It should be appreciated that when more than one octane boosting fuel additive is usedfWhen these values refer to fuel additives in the fuelfThe total amount of (a).

The fuel composition may comprise at least one other additional fuel additive. Examples of such other additives that may be present in the fuel composition include detergents, friction modifiers/antiwear additives, corrosion inhibitors, combustion modifiers, antioxidants, valve seat recession additives, dehazing/demulsifying agents, dyes, markers, odorants, antistatic agents, biocides, and lubricity improvers. Additional octane improvers may also be used in the fuel composition, i.e., without octane boosting fuel additivesfThe octane improver of (1).

The fuel composition is used in a spark-ignition internal combustion engine. Examples of spark-ignition internal combustion engines include direct injection spark-ignition engines and port fuel injection spark-ignition engines. Spark ignition internal combustion engines may be used in automotive applications, for example in vehicles such as passenger cars.

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

Examples

In the following examples, LCMS analysis was performed using the conditions provided in the following table: