ZA200504812B

ZA200504812B - Use of metal to prevent spark plugs fouling from iron

Info

Publication number: ZA200504812B
Application number: ZA200504812A
Authority: ZA
Inventors: Kevin Adamson; Stephen Leonard Cook; Simon Christopher Mulqueen; Keith Woodall
Original assignee: Ass Octel
Priority date: 2002-12-18
Filing date: 2003-12-12
Publication date: 2006-09-27
Also published as: WO2004055136A1; AU2003292412A1; GB0229442D0; PE20040823A1; CL2003002657A1

Description

USE OF METAL TO PREVENT SPARK PLUGS FOULING FROM IRON

: The present invention relates to a use. The present invention relates to fuel compositions containing fuel additives and the use thereof. In particular, the invention ’ 5 relates to additives effective in preventing fouling of spark plugs or reducing or ameliorating adverse effects of spark plug fouling in internal combustion engines by iron or iron compounds.

Metal and especially metal containing additives have been incorporated in fuel compositions for many years. The additives may provide a number of effects on the fuel. Certain additives are known to improve the combustion properties of the fuel, for example certain additives may increase the octane number of petroleum fuels. The additives may also provide an effect during combustion, in particular during combustion in an internal combustion engine. For example metal or metal containing additives may deposit metal or metal compounds on surface of an internal combustion engine during combustion. In particular metal or metal compounds may deposit on the valves or valve seats of an internal combustion engine. Such deposits may protect these components of the engine from wear caused during operation, for example the deposits may protect the valve seats from wear and consequential recession. it has also been found that certain metals may be deposited such that detrimental effects are observed. For example it has been found that iron or iron compounds when present at high treat rates may deposit on the spark plugs of internal combustion engines. In particular iron components may deposit on the insulating section of a spark plug and to such an extent that the insulating properties of the insulating section are degraded. When degraded to a sufficient degree, on sparking the designed spark path may not be followed and some discharge through the iron-containing deposits may occur, particularly in critical vehicles and after extended mileage. This may lead to mis- firing of the engine which may reduce efficiency, may be noticeable to the driver or may » 30 in extreme circumstances lead to reduced operability of an engine or a vehicle to which it : is fitted.

We have found that when iron or an iron compound is provided in a fuel in an amount to provide iron in an amount of at least 15 mg per kg of fuel, on combustion spark plug fouling may occur and detrimental be effects observed, particularly in critical vehicles and after extended mileage. The combustion products of iron and/or iron compounds , include iron oxides. For example, when a fuel comprising ferrocene is dosed in fuel in ( an amount to provide 18 mg of iron per kg of fuel, misfiring of an internal combustion . engine may occur. Ferrocene is a well-known metal-containing fuel additive with a significant capability to increase octane quality in unleaded gasoline. It is used as an octane trimming additive at refineries to enhance octane quality in gasoline, to assist meeting gasoline octane specifications.

It is recommended that ferrocene be added to fuel at a treat rate of no greater than 30mg Ferrocene/kg. Ferrocene comprises 30wt% iron, so this treat rate equates to 9mg

Fe/kg. For octane enhancement purposes, iron added as ferrocene is used typically at a treat rate of 9mg Fe/kg. However, this treat rate may sometimes be exceeded unintentionally or intentionally to enhance octane quality in gasoline having particularly low octane rating to ensure that gasoline octane specifications are met.

It has also been found that low quality/purity iron compounds such as ferrocene compositions containing high amounts of impurities may cause spark plug fouling at treat rates below the recommended maximum of 30mg Ferrocene/kg (9mg Fe/kg) of high quality products.

There is consequently a desire to provide a means by which plug fouling caused by high iron treat rates or by impure iron compositions may be reduced and/or prevented.

In a first aspect there is provided use of potassium and/or a potassium compound for prevention and/or inhibition of, and/or ameliorating the adverse effects of, fouling of a spark plug of an internal combustion engine by iron, an iron compound or a combustion product thereof. . In a second aspect there is provided a method for preventing and/or inhibiting of fouling o 30 of a spark plug of an internal combustion engine by iron, an iron compound or a i combustion product thereof, comprising; (a) providing a fuel composition comprising (i) iron and/or an iron compound, (ii) potassium and/or a potassium compound; and (iii) a fuel; (b) combusting the fuel composition in an internal combustion engine by igniting the fuel with a spark plug, such that the potassium and/or a potassium compound prevents and/or inhibits, and/or ameliorates the adverse effects of, fouling of the spark plug by the iron, iron compound or combustion product thereof. . In a third aspect there is provided a fuel composition comprising (i) iron and/or an iron . compound in an amount to provide iron in an amount of at least 15 mg per kg of fuel; (ii) potassium and/or a potassium compound; and (iii) a fuel.

In a fourth aspect there is provided use of potassium and/or a potassium compound for prevention and/or inhibition of fouling of a spark plug of an internal combustion engine by iron, an iron compound or a combustion product thereof.

In a fifth aspect there is provided a method for preventing and/or inhibiting of fouling of a spark plug of an internal combustion engine by iron, an iron compound or a combustion product thereof, comprising; (a) providing a fuel composition comprising (i) iron and/or an iron compound, (ii) potassium and/or a potassium compound; and (iii) a fuel; (b) combusting the fuel composition in an internal combustion engine by igniting the fuel with a spark plug, such that the potassium and/or a potassium compound prevents and/or inhibits fouling of the spark plug by the iron, iron compound or combustion product thereof.

The potassium is present in amount to provide the required reduction and/or prevention of, and/or amelioration of the adverse effects of, spark plug fouling.

The term “plug fouling” will understood by one skilled in the art. It is typically taken to mean deposition on a plug which may cause operability problems or performance degradation, for example as described and tested in the present Examples.

IRON

Iron or iron compounds may be added to fuels for a number of reasons. Volatile iron- : 30 containing additives may contribute to increased driveability, in both the short and long term. Initially, an octane improvement results from the use of iron materials, such as

PLUTOcen™. Iron compounds are known to reduce in-cylinder deposits through oxidation of carbonaceous material, again, a volatile species would be expected to provide such benefits throughout the cylinder as opposed to only those parts wetted by liquid fuel. Thin films of iron containing material deposited on the cylinder walls are suspected as providing fuel consumption and emissions reduction benefits, especially . for CO, NOx and unburned hydrocarbons. . Preferably the iron and/or iron compound is an iron compound.

Preferably the iron compound is a ferrocene and/or a substituted ferrocene.

Preferably the iron and/or iron compound is a ferrocene and/or a substituted ferrocene.

Preferably the iron compound is a ferrocene.

Preferably the iron and/or iron compound is a ferrocene.

Preferably the iron compound is an iron complex selected from bis-cyclopentadienyl iron and substituted bis-cyclopentadienyl iron.

Preferably the iron and/or iron compound is an iron complex selected from bis- cyclopentadieny! iron and substituted bis-cyclopentadienyl iron.

Preferably the iron compound is bis-cyclopentadienyl iron.

Preferably the iron and/or iron compound is bis-cyclopentadienyl! iron.

The iron compound may be an iron complex of bis-cyclopentadienyl or substituted bis- cyclopentadienyl complex of iron, wherein the substituents can be, for example, one or more C,.s alkyl groups, preferably C,., alkyl groups. A combination of such iron complexes may also be used. : . Suitable alkyl-substituted-dicyclopentadienyl iron complexes are cyclopentadienyl- (methylcyclopentadienyl) iron, cyclopentadienyl(ethyl-cyclopentadienyl) iron, bis- . (methylcyclopentadienyl) iron, bis-(ethylcyclopentadienyl) iron, bis-(1,2-dimethyl- cyclopentadienyl) iron, and bis-(1-methyl-3-ethylcyclo-pentadienyl) iron. These iron complexes can be prepared by the processes taught in US-A-2680756, US-A-2804468,

GB-A-0733129 and GB-A-0763550. Another volatile iron complex is iron pentacarbonyl.

Suitable iron complexes are bis-cyclopentadienyl iron and/or bis-(methylcyclo-pentadienyl) i iron. . A highly preferred iron complex is ferrocene (i.e. bis-cyclopentadienyl iron). 5

The co-ordination chemistry relevant to the solubilisation of transition metals, including iron, in hydrocarbon solvents, e.g. diesel fuel, is well known to those skilled in the art (see e.g. WO-A-87/01720 and WO-A-92/20762).

A wide range of so-called "substituted ferrocenes” are known and may be used in the present invention (see e.g. Comprehensive Organic Chemistry, Eds. Wilkinson et al,

Pergamon 1982, Vol. 4:475-494 and Vol. 8:1014-1043). Substituted ferrocenes for use in the invention include those in which substitution may be on either or both of the cyclopentadieny! groups. Suitable substituents include, for example, one or more Cis alkyl groups, preferably C,., alkyl groups.

Particularly suitable alkyl-substituted-dicyclopentadienyl iron complexes (substituted ferrocenes) include cyclopentadienyl(methylcyclopentadienyl) iron, bis- (methylcyclopentadienyl) iron, bis-(ethylcyclopentadienyl) iron, bis-(1,2- dimethylcyclopentadienyl) iron and 2,2-diethyliferrocenyi-propane.

Other suitable substituents that may be present on the cyclopentadienyl rings include cycloalkyl groups such as cyclopentyl, aryl groups such as tolylphenyi, and acetyl groups, such as present in diacetyl ferrocene. A particularly useful substituent is the hydroxyisopropyl group, resulting in (a-hydroxyisopropyl) ferrocene. As disclosed in

WO-A-94/09091, (a-hydroxyisopropyl)ferrocene is a room temperature liquid.

Ferrocenes linked by a “bridge” may used in the present invention. Suitable compounds } are taught in PCT/GB01/03897 and PCT/GB2002/004002. . Other organometallic complexes of iron may also be used in the invention, to the extent that these are fuel soluble and stable. Such complexes include, for example, iron pentacarbonyl, di-iron nonacarbonyl, (1,3-butadiene)-iron tricarbonyl, and (cyclopentadienyl)-iron dicarbonyl dimer. Salts such as di-tetralin iron tetraphenylborate (Fe(CioH12)2(B(CsHs)s)2) may also be employed.

. i As a result of a combination of their solubility, stability, high iron content and, above all, volatility, the substituted ferrocenes are particularly preferred iron compounds for use in , the invention. Ferrocene itself is an especially preferred iron compound on this basis.

Ferrocene of suitable purity is sold in a range of useful forms as PLUTOcen™™ and as solutions, Satacen™ "both by Octel Deutschland GmbH.

The iron compounds for use in the invention need not feature iron-carbon bonds in order to be fuel soluble and stable. Salts may be used; these may be neutral or overbased.

Thus, for example, overbased soaps including iron stearate, iron oleate and iron naphthenate may be used. Methods for the preparation of metal soaps are described in

The Kirk-Othmer Encyclopedia of Chemical Technology, 4th Ed, Vol. 8:432-445, John

Wiley & Sons, 1993. Suitable stoichiometric, or neutral, iron carboxylates for use in the invention include the so-called 'drier-iron’ species, such as iron tris(2-ethylhexanoate) [19583-54-1].

Iron complexes not featuring metal-carbon bonds and not prepared using carbonation may also be used in the invention provided these are adequately fuel soluble and stable.

Examples include complexes with B-diketonates, such as tetramethylheptanedionate.

Iron complexes of the following chelating ligands are also suitable for use in the invention: e aromatic Mannich bases such as those prepared by reaction of an amine with an aldehyde or ketone followed by nucleophilic attack on an active hydrogen containing compound, e.g. the product of the reaction of two equivalents of (tetrapropenyl)phenol, two of formaldehyde and one of ethylenediamine, e hydroxyaromatic oximes, such as (polyisobutenyl)-salicylaldoxime. These may be prepared by reaction of (polyisobutenyl)phenol, formaldehyde and hydroxylamine; e Schiff bases such as those prepared by condensation reactions between aldehydes or ketones (e.g. (tert-butyl)-salicylaldehyde) and amines (e.g. dodecylamine). A tetradentate ligand may be prepared using ethylenediamine (half equivalent) in place of dodecylamine; e substituted phenols, such as 2-substituted-8-quinolinols, for example 2-dodecenyl-8- quinolinol or 2-N-dodecenylamino-methylphenol; substituted phenols, such as those wherein the substituent is NR, or SR in which R is a long chain (e.g. 20-30 C atoms) hydrocarbyl group. In the case of both o- and - , substituted phenols, the aromatic rings may beneficially be further substituted with hydrocarbyl groups, e.g. lower alkyl groups; , e carboxylic acid esters, in particular succinic acid esters such as those prepared by reaction of an anhydride (e.g. dodecenyl! succinic anhydride) with a single equivalent of an alcohol (e.g. triethylene glycol); e acylated amines. These may be prepared by a variety of methods well known to those skilled in the art. However, particularly useful chelates are those prepared by reaction of alkenyl substituted succinates, such as dodecenyl succinic anhydride, with an amine, such as N,N'-dimethyl ethylene diamine or methyi-2-methylamino-benzoate; e amino-acids, for example those prepared by reaction of an amine, such as dodecylamine, with an o,B-unsaturated ester, such as methylmethacrylate. In cases where a primary amine is used, this may be subsequently acylated, such as with oleic acid or oleyl chloride; hydroxamic acids, such as that prepared from the reaction of hydroxylamine with oleic acid, « linked phenols, such as those prepared from condensation of alkylated phenols with formaldehyde. Where a 2:1 phenol:formaldehyde ratio is used the linking group is CH..

Where a 1:1 ratio is employed, the linking group is CH,OCHj; eo alkylated, substituted pyridines, such as 2-carboxy-4-dodecylpyridine; e borated acylated amines. These may be prepared by reaction of a succinic acylating agent, such as poly(isobutylene)succinic acid, with an amine, such as tetraethylenepentamine. This procedure is then followed by boronation with a boron oxide, boron halide or boronic acid, amide or ester. Similar reactions with phosphorus acids result in the formation of phosphorus-containing acylated amines, also suitable for providing an oil-soluble iron chelate for use in the invention; « pyrrole derivatives in which an alkylated pyrrole is substituted at the 2-position by

OH, NH,, NHR, CO;H, SH or C(O)H. Particularly suitable pyrrole derivatives include 2- : carboxy-t-butylpyrroles; sulphonic acids, such as those of the formula R'SO;H, where R is a Cqo to about Cy hydrocarbyl group, e.g. dodecylbenzene sulphonic acid; « organometallic complexes of iron, such as ferrocene, substituted ferrocenes, iron naphthenate, iron succinates, stoichiometric or over-based iron soaps (carboxylate or sulphonate), iron picrate, iron carboxylate and iron -diketonate complexes.

Claims

: CLAIMS ’

) 1. Use of potassium and/or a potassium compound for the prevention and/or inhibition of fouling of a spark plug of an internal combustion engine by iron; an iron compound wherein the iron compound is an iron complex selected from bis-cyclopentadienyl iron and substituted bis-cyclopentadienyl iron; or a combustion product thereof.
2. A method for preventing and/or inhibiting of fouling of a spark plug of an internal combustion engine by iron, an iron compound or a combustion product thereof, comprising providing a fuel composition comprising (i) iron and/or an iron compound wherein the iron compound is an iron complex selected from bis-cyclopentadieny! iron and substituted bis-cyclopentadieny! iron, (ii) potassium and/or a potassium compound; and (iii) a fuel, combusting the fuel composition in an internal combustion engine by igniting the fuel with a spark plug, such that the potassium and/or a potassium compound prevents and/or inhibits fouling of the spark plug by the iron, iron compound or combustion product thereof.
3. The use or method of any one of the preceding claims wherein the potassium compound is a potassium sulphonate.
4. The use or method of any one of the preceding claims wherein the iron compound is bis-cyclopentadienyl iron.
5. The use or method of claim 1 or 2 wherein the iron and/or an iron compound provides iron in an amount of at least 15 mg per kg of fuel.
6. The use or method of any one of the preceding claims wherein the iron and/or an iron compound provides iron in an amount of at least 18 mg per kg of fuel.
7. The use or method of any one of the preceding claims wherein the iron and/or an iron compound provides iron in an amount of at least 22.5 mg per kg of fuel.
8. The use or method of any one of the preceding claims wherein the iron and/or an iron compound provides iron in an amount of at least 30 mg per kg of fuel. AMENDED SHEET 24.05.2006
9. The use or method of any one of claims 1 or 2 wherein the iron and/or an iron . compound provides iron in an amount of from 15 to 30 mg per kg of fuel.
10. The use or method of any one of the preceding claims wherein the potassium and/or a potassium compound provides potassium in an amount of at least 3 mg per kg of fuel.
11. The use or method of any one of the preceding claims wherein the potassium and/or a potassium compound provides potassium in an amount of from 3 to 20 mg per kg of fuel.
12. The use or method of any one of the preceding claims wherein the potassium and/or a potassium compound provides potassium in an amount of from 5 to 15 mg per kg of fuel.
13. The use or method of any one of the preceding claims wherein the potassium and/or a potassium compound provides potassium in an amount of from 6 to 12 mg per kg of fuel.
14. The use or method of any one of the preceding claims wherein the ratio by weight of potassium to iron is from 1:20 to 1:1.
15. The use or method of claim 14 wherein the ratio by weight of potassium to iron is from 1:10 to 1:1.
16. The use or method of claim 15 wherein the ratio by weight of potassium to iron is from 1:5 to 1:1.
17. Use of a metal and/or a metal compound for the prevention and/or inhibition of fouling of a spark plug of an internal combustion engine by iron, an iron compound or a combustion product thereof, wherein the metal or the metal of the metal compound is selected from manganese, cerium, and an s block metal selected from magnesium and calcium. AMENDED SHEET 24.05.2006

Co
18. A method for preventing and/or inhibiting of fouling of a spark plug of an internal combustion engine by iron, an iron compound or a combustion product thereof, . comprising providing a fuel composition comprising (i) iron and/or an iron compound, (ii) a metal and/or a metal compound; and (iii) a fuel, combusting the fuel composition in an internal combustion engine by igniting the fuel with a spark plug, such that the metal and/or a metal compound prevents and/or inhibits fouling of the spark plug by the iron, iron compound or combustion product thereof, wherein the metal or the metal of the metal compound is selected from manganese, cerium, and an s block metal selected from magnesium and calcium.
19. A fuel composition comprising (i) iron and/or an iron compound in an amount to provide iron in an amount of at least 15 mg per kg of fuel, (ii) a metal and/or a metal compound; and (iii) a fuel, wherein the metal or the metal of the metal compound is selected from manganese, cerium and an s block metal selected from magnesium and calcium.
20. The invention of claim 18 or 19 wherein the iron compound is an iron complex selected from bis-cyclopentadienyl iron and substituted bis-cyclopentadienyl iron.
21. The invention of claim 18, 19 or 20 wherein the fuel composition further comprises potassium and/or a potassium compound.
22. The invention of claim 21 wherein the potassium compound is a potassium sulphonate.
23. The invention of claim 21 wherein the potassium and/or a potassium compound provides potassium in an amount of at least 3 mg per kg of fuel.
24. The invention of claim 21 wherein the ratio by weight of potassium to iron is from 1:20 to 1:1.
25. Use as substantially hereinbefore described with reference to any one of the AMENDED SHEET 24.05.2006

! LY WO 2004/055136 35 PCT/GB2003/005427 Examples.

Y

.
26. A fuel composition as substantially hereinbefore described with reference to any one of the Examples. AMENDED SHEET 24.05.2006