EP1098953A1

EP1098953A1 - Fuel compositions containing propoxilate

Info

Publication number: EP1098953A1
Application number: EP99932855A
Authority: EP
Inventors: Wolfgang Günther; Knut Oppenländer; Harald Schwahn; Irene Trötsch-Schaller
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1998-07-09
Filing date: 1999-07-08
Publication date: 2001-05-16
Anticipated expiration: 2019-07-08
Also published as: CA2336878C; EE04554B1; EP1098953B1; BR9911936A; HUP0102857A2; PL345511A1; HRP20010100A2; NO20010120L; DE59911148D1; IL140401A0; IL140401A; AU4908999A; PL191308B1; SK285356B6; JP2002520444A; KR100649460B1; CA2336878A1; ES2234271T3; MY129096A; PT1098953E

Abstract

The invention relates to fuel compositions for internal combustion engines comprising a main quantity of a liquid hydrocarbon fuel and a pure portion of at least one propoxilate additive of formula (I), wherein n is an integer ranging from 10 to 20, and R<1> represents a straight-chain or branched C8-C18 alkyl radical or C8-C18 alkenyl radical; optionally in combination with at least one detergent additive such as, for example, a polyalkylamine of formula (II) R<2>-NH2, wherein R<2> represents a straight-chain or branched polyalkyl radical having a numerical average molecular weight ranging from approximately 500 to approximately 5000. The invention also relates to fuel additive compositions which contain propoxilates of formula (I) and optionally contain additional additives such as said polyalkylamines of formula (II) used as intake valve cleaners.

Description

Fuel compositions containing propoxylate

The present invention relates to new fuel compositions containing propoxylate and to novel additive concentrates.

Carburetors and intake systems of gasoline engines, but also injection systems for fuel metering in gasoline and diesel engines are increasingly contaminated. The contamination is caused by dust particles from the air drawn in by the engine, unburned hydrocarbon residues from the combustion chamber and the ventilation gases from the crankshaft housing that are led into the carburetor.

These residues shift the air-fuel ratio at idle and in the lower part-load range, so that the mixture becomes richer and the combustion becomes incomplete. As a result, the proportion of unburned or partially burned hydrocarbons in the exhaust gas increases and gasoline consumption increases.

It is known that in order to avoid these disadvantages, fuel additives are used to keep valves and carburettor or injection systems clean (see, for example: M. Rossenbeck in catalysts, surfactants, mineral oil additives, ed. J. Falbe, U. Hasserodt, p. 223 , G. Thieme Verlag, Stuttgart 1978). Depending on the mode of action and preferred site of action of such detergent additives, a distinction is made between two generations. The first generation of additives could only prevent the formation of deposits in the intake system, but not remove existing deposits. Second-generation additives, on the other hand, can prevent and remove deposits (keep-clean and clean-up effect). This is made possible in particular by their excellent thermal stability in zones of higher temperature, such as, in particular, at the inlet valves.

The molecular construction principle of these additives of the second generation, which act as detergents, is based on the linking of polar structures with mostly higher molecular weight, non-polar or oleophilic residues.

Typical representatives of the second generation of additives are products based on polyisobutene in the non-polar part of the molecule, in particular additives of the polyisobutylamine type. Such detergents, starting from polyisobutenes, can be prepared by two different multistage synthesis processes: The first process is carried out by chlorinating the polymeric base body, followed by nucleophilic substitution of the polymeric base body. pers by amines or preferably ammonia. A disadvantage of this process is the use of chlorine, which has the consequence that products containing chlorine or chloride occur, which is no longer desirable today. In the second process, the polyisobutylamines are prepared starting from polyisobutene via hydroformylation and then reductive amination according to EP-A-0 244 616.

Detergent additives, which can come from a variety of chemical substance classes, are generally used in combination with a carrier oil. The carrier oils have an additional "washing function", often support and promote the effectiveness of the detergents and can help to reduce the amount of detergent required. Certain detergents only work in combination with a carrier liquid. Viscous, high-boiling and in particular thermostable liquids are usually used as carrier oils. They coat the hot metal surface (eg the inlet valves) with a thin film of liquid and thereby prevent or delay to a certain extent the formation or deposition of decomposition products on the metal surfaces, but without being able to replace the detergent additive component .

Suitable carrier oils for fuels for internal combustion engines are e.g. B. high-boiling, refined mineral oil fractions, but also synthetic liquids. Suitable mineral carrier oils are e.g. B. in the oil processing fractions.

Examples of suitable synthetic carrier oils are polyolefins, (poly) esters, (poly) alkoxylates, and in particular aliphatic polyethers, aliphatic polyetheramines, alkylphenol-started polyethers and alkylphenol-started polyetheramines.

Adducts of butylene oxide with alcohols have excellent solubility in fuels, but are comparatively expensive products and the starting material butylene oxide has to be produced in a relatively complex manner.

Inexpensive carrier oils can be made available in the form of adducts of propylene oxide with alcohols.

EP-A-0 704 519 describes propoxylates as a carrier oil component in combination with a high molecular weight amine and a hydrocarbon polymer. EP-A-0 374 461 describes propoxylates of this type for use as carrier oil in combination with esters of mono- or polycarbonate acids and alcohols or polyols and detergents containing amino or amido groups. EP-A-0 374 461 expressly teaches (see p. 4, lines 29ff.) That the sole use of the propoxylates described therein leads to an insufficient reduction of the inlet valve deposits, namely to values of 80 to 220 mg per valve.

However, the known additive systems from the prior art, which contain carrier oils based on propylene oxide, do not yet show the optimal cleaning effect in the engine. Furthermore, such adducts of propylene oxide with alcohols often cause problems because of their limited solubility in fuels and because of their poor compatibility with other additives, so that segregation can occur. This effect is particularly dramatic when additive concentrates - as such additive systems are usually marketed - are to be formulated.

The invention was therefore based on the object of providing novel fuel compositions for internal combustion engines with improved properties. In particular, the new fuel compositions should lead to significantly reduced inlet valve deposits.

Surprisingly, the object according to the invention was achieved by providing a fuel composition for fuel engines, comprising a main amount of a liquid hydrocarbon fuel and a cleaning component, in particular reducing intake valve deposits, of at least one propoxylate additive of the formula I.

wherein

n stands for an integer value from 10 to 20 and

R ^{1 represents} a straight-chain or branched Cs-Cis-alkyl or C ₈ -Ci ₈ -alkenyl radical, preferably Cs-Cis-alkyl. The fuel compositions according to the invention have the surprising advantage that they reduce deposits in the area of the inlet valves significantly better than the corresponding shorter-chain or longer-chain propoxylates. This is particularly surprising because it has previously been assumed that compounds of the type used can only be used as carrier oils for fuel compositions, but carrier oils per se do not have a satisfactory cleaning effect on the intake system.

In order to bring about the effect shown according to the invention, the propoxylates of the above formula I should be used in a proportion of about 50 to 5000 mg / kg fuel, preferably about 100 to 2500 mg / kg fuel, in particular about 300 to 1000 mg / kg fuel. be applied.

The above object according to the invention is also achieved by providing fuel compositions for internal combustion engines which contain a major amount of a liquid hydrocarbon fuel and a cleaning component of an additive combination which significantly reduces contaminants in the intake system, the additive combination comprising:

i) at least one propoxylate additive, preferably alkanol propoxylate, formula I above and

ii) at least one detergent additive.

The fuel compositions according to the invention which have the above-mentioned additive combination also surprisingly bring about significantly reduced inlet valve deposits.

Examples of suitable detergent additives ii) are those which show detergent action or valve seat wear-inhibiting action and in particular those with at least one hydrophobic hydrocarbon radical with a number average molecular weight (M _N ) of 85 to 20,000 and at least one polar, preferably terminal grouping selected from

(a) mono- or polyamino groups with up to 6 nitrogen atoms, at least one nitrogen atom having basic properties,

(b) nitro groups, optionally in combination with hydroxyl groups, (c) hydroxyl groups in combination with mono- or polyamino groups, at least one nitrogen atom having basic properties,

(d) carboxyl groups or their alkali metal or alkaline earth metal salts,

(e) sulfonic acid groups or their alkali metal or alkaline earth metal salts,

(f) polyoxy-C ₂ -C -alkylene groupings which are terminated by hydroxyl groups, mono- or polyamino groups, where at least one nitrogen atom has basic properties, or are terminated by carbamate groups,

(g) carboxylic ester groups,

(h) Groups derived from succinic anhydride with hydroxyl and / or amino and / or amido and / or imido groups and

(i) Groups generated by Mannich reaction of substituted phenols with aldehydes and mono- or polyamines.

The hydrophobic hydrocarbon radical preferably has a number-average molecular weight (M _N ) of 113 to 10,000, in particular 300 to 5000. As a typical hydrophobic hydrocarbon residue, especially in combination with the polar groups (a), (c), (h) and (i), there are the polypropenyl, polybutenyl and polyisobutenyl residues, each with M _N = 300 to 5000 , in particular 500 to 2500, especially 750 to 2250, into consideration.

Examples of additives containing mono- or polyamino groups (a) are preferably polyalkene mono- or polyalkene polyamines based on polypropene or highly reactive (ie with predominantly terminal double bonds - mostly in the α- and β-position) or conventional (ie with predominantly centered) Double bonds) polybutene or polyisobutene with M _N = 300 to 5000. Additives of this type based on highly reactive polyisobutene, which are obtained from the polyisobutene, which can contain up to 20% by weight of n-butene units, by hydroformylation and reductive amine nation with ammonia, monoamines or polyamines such as dimethylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepenta can be prepared in are known in particular from EP-A 244 616. If the additives of polybutene or polyisobutene are mainly used central double bonds (usually in the ß and γ positions), the production route is available by chlorination and subsequent amination or by oxidation of the double bond with air or ozone to form the carbonyl or carboxyl compound and subsequent amination under reductive (hydrogenating) conditions. For the amination, the same amines can be used here as for the reductive amination of the hydroformylated, highly reactive polyisobutene. Corresponding additives based on polypropene are described in particular in WO-A 94/24231.

Preferred examples of amine additives of this type are polyalkylamines of the formula II

R ² -NH ₂ (II)

wherein

R ^{2 stands} for a straight-chain or branched polyalkyl radical with a number average molecular weight of about 500 to 5000.

Further preferred additives containing monoamino groups (a) are the hydrogenation products of the reaction products of polyisobutenes with an average degree of polymerization P = 5 to 100 with nitrogen oxides or mixtures of nitrogen oxides and oxygen, as are described in particular in WO-A 97/03946.

Further preferred additives containing monoamino groups (a) are the compounds obtainable from polyisobutene epoxides by reaction with amines and subsequent dehydration and reduction of the amino alcohols, as are described in particular in DE-A 196 20 262.

Additives containing nitro groups, optionally in combination with hydroxyl groups, (b) are preferably reaction products of polyisobutenes with an average degree of polymerization P = 5 to 100 or 10 to 100 with nitrogen oxides or mixtures of nitrogen oxides and oxygen, as described in particular in WO-A 96 / 03367 and WO-A 96/03479. These reaction products are usually mixtures of pure nitropolyisobutanes (e.g. α, ß-dinitropolyisobutane) and mixed hydroxynitropolyisobutanes (e.g. α-nitro-ß-hydroxypolyisobutane).

Additives containing hydroxyl groups in combination with mono- or polyamino groups (c) are, in particular, reaction products of polyisobutene epoxides, obtainable from polyisobutene preferably having predominantly double bonds with M _N = 300 to 5000, with ammonia, mono- or polyamines, as described in particular in EP-A-0 476 485.

Additives containing carboxyl groups or their alkali metal or alkaline earth metal salts (d) are preferably copolymers of C ₂ -C ₄₀ olefins with maleic anhydride with a total molar mass of 500 to 20,000, the carboxyl groups of which are wholly or partly associated with the alkali metal or alkaline earth metal salts and a remaining radical of the carboxyl groups are reacted with alcohols or amines. Such additives are known in particular from EP-A-0 307 815. Such additives mainly serve to prevent valve seat wear and, as described in WO-A 87/01126, can advantageously be used in combination with conventional fuel detergents such as poly (iso) butenamines or polyetheramines.

Additives containing sulfonic acid groups or their alkali metal or alkaline earth metal salts (e) are preferably alkali metal or alkaline earth metal salts of an alkyl sulfosuccinic acid ester, as described in particular in EP-A-0 639 632. Such additives mainly serve to prevent valve seat wear and can advantageously be used in combination with conventional fuel detergents such as poly (iso) butenamines or polyetheramines.

Polyoxy-C ₂ -C -alkylene (f) additives are preferably polyethers or polyetheramines which are obtainable by reaction of C ₂ - to C ₆ o-alkanols, C ₆ - to C ₃ o-alkanediols, mono- or di-C ₂ -C ₃ o-alkylamines, -C-C o-alkylcyclohexanols or -C-C ₃ o-alkylphenols with 1 to 30 mol ethylene oxide and / or propylene oxide and / or butylene oxide per hydroxyl group or amino group and, in the case of the polyether amines, by subsequent reductive amination with ammonia, monoamines or polyamines are available. Such products are described in particular in EP-A-0 310 875, EP-A-0 356 725, EP-A-0 700 985 and US-A-4, 877, 416. In the case of polyethers, such products also have carrier oil properties. Typical examples are tridecanol or isotidecanol butoxylates, isononylphenol butoxylates and polyisobutenol butoxylates and propoxylates as well as the corresponding reaction products with ammonia.

Additives containing carboxylic acid ester groups (g) are preferably esters of mono-, di- or tricarboxylic acids with long-chain alkanols or polyols, in particular those with a minimum viscosity of 2 mm ² / s at 100 ° C., as described in particular in

DE-A-38 38 918 are described. Aliphatic or aromatic acids can be used as mono-, di- or tricarboxylic acids long-chain representatives with, for example, 6 to 24 carbon atoms are particularly suitable as ester alcohols or polyols. Typical representatives of the esters are adipates, phthalates, isophthalates, terephthalates and trimellitates of iso-octanol, iso-nonanol, iso-decanol and iso-tridecanol. Such products also have carrier oil properties.

Groupings derived from succinic anhydride and containing hydroxyl and / or amino and / or amido and / or imido groups (h) are preferably corresponding derivatives of polyisobutenylsuccinic anhydride which are obtained by reacting conventional or highly reactive polyisobutene with M _N = 300 up to 5000 with maleic anhydride can be obtained thermally or via chlorinated polyisobutene. Of particular interest here are derivatives with aliphatic polyamines such as ethylene diamine, diet ylene triamine, triethylene tetramine or tetraethylene pentamine. Such gasoline fuel additives are described in particular in US-A-4,849,572.

Additives containing groups (i) produced by Mannich reaction of substituted phenols with aldehydes and mono- or polyamines are preferably reaction products of polyisobutene-substituted phenols with formaldehyde and mono- or polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetrahedral pentamine or dimethylaminopropylamine. The polyisobutenyl-substituted phenols can originate from conventional or highly reactive polyisobutene with M _N = 300 to 5000. Such “polyisobutene Mannich bases” are described in particular in EP-A-0 831 141.

For a more precise definition of the individual additives listed, reference is expressly made here to the disclosures of the abovementioned prior art documents.

In the fuel compositions according to the second embodiment described above, the additives i) and the additives ii), such as. B. of formula II, in a total amount of about 100 to 10,000 mg / kg, preferably about 300 to 5000 mg / kg, in particular about 500 to 3000 mg / kg, fuel. The additives i) and ii), in particular of the formula I and the formula II, are in a molar ratio in the range from about 1:10 to 10: 1, such as, for. B. approximately in the range from 1: 5 to approximately 5: 1, in particular in the range from approximately 1: 2 to 2: 1.

C ₈ -C ₈ alkyl radicals suitable according to the invention in additives of the formula I are straight-chain or branched, saturated carbon chains with 8 to 18 carbon atoms. For example, The following radicals are mentioned: n-hexyl, 1-, 2- or 3-methylpentyl, unbranched heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl and the one or more branched analogues thereof. Preferred long-chain radicals are branched or unbranched C 1 -C 6 -f in particular C ₂ -C ₄ alkyl. Tridecyl residues are particularly preferred.

C ₈ -C ₈ alkenyl residues suitable according to the invention in additives of the formula I are straight-chain or branched carbon chains with at least one carbon-carbon double bond and with 8 to 18 carbon atoms. Examples of monounsaturated C ₈ -C ₈ alkenyl radicals are radicals such as unbranched octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, pentadecenyl, hexadecenyl, heptadecenyl and octadecenyl, and the branched analogues thereof, the double bond in any one Position can occur. According to the invention, both the ice and the trans isomers of the above C ₈ -C ₈ alkenyl radicals are included. Preferred monounsaturated long-chain radicals are the C 1 -C ₆ -alkenyl radicals.

Polyalkyl radicals in additives of the formula II which are suitable according to the invention are preferably obtainable by homo- or copolymerization of straight-chain or branched C ₂ -C n-alkenes, C ₂ -C ₆ -alkenes and in particular C ₂ -C -alkenes being preferred. Particularly preferred C ₂ -C ₄ alkenes are 1-alkenes, such as propylene, 1-butene and isobutene. The number average molecular weight of such polyalkyl radicals is approximately in the range from 500 to 5000, preferably approximately 800 to 1500, in particular approximately 1000. For example, the polyalkyl radical can be derived from a copolymer of 1-butene and isobutene and z. B. have a number average molecular weight of about 800 to about 1500.

Propoxylates of the formula I which are particularly preferred according to the invention are compounds in which R ^{1 represents} straight-chain or branched alkyl radicals having 10 to 16 carbon atoms, or mixtures thereof. Propoxylates of the formula I are particularly preferred in which the radical R ^{1 is} an alkyl radical having 12 to 14 carbon atoms or a mixture of such alkyl radicals. A propoxylate of the formula I in which the radical R ^{1 has} 13 carbon atoms is particularly preferred.

Another group of propoxylates preferred according to the invention is composed of 12 to 18 repeating units, in particular 14 to 17 and especially 14 to 16 repeating units of the formula

built up. The most preferred class of propoxylates includes 15 recurring propoxylate units. It should be noted that the above numerical values for n can also represent mean values, since many of the known production methods for such adducts of alkylene oxides with alcohols usually lead to a product mixture with a different molecular weight distribution.

According to the invention the most preferred alkoxylates of the formula I are adducts of 14 to 16, in particular 15 propylene oxide units of the above formula to a branched Cι ₃ alcohol, in particular Cι ₃ monoalcohol, is. According to the invention useful branched Cι ₃ alcohols are e.g. . B. also obtainable by oligomerization of C ₂ -C ₆ -01efins, in particular C ₃ - or C ₄ -01efinen, and subsequent hydroformylation. An optionally occurring reaction mixture, the z. B. could include various alcohol isomers, can be used directly for the preparation of the additive components used according to the invention. However, the reaction mixture can also be separated beforehand if necessary.

The alkanol propoxylates preferably used according to the invention are prepared in a conventional manner by adding an alcohol as a starter molecule with propylene oxide in the presence of alkali, such as. B. sodium hydroxide solution, potassium hydroxide solution, sodium methylate, potassium methylate or other alkali alkoxides, at temperatures in the range of about 120 to 160 ° C, preferably about 130 to 160 ° C, to the desired adducts. After the alkoxylation has ended, the propoxylate is freed of the catalyst, for example by treatment with magnesium silicate. The preparation is thus carried out in analogy to the phenol-started alkoxylates described in DE-A-41 42 241.

The polyalkylamines of the general formula II are compounds known per se and can be prepared by hydroformylation of reactive polyalkenes and subsequent reductive amination of the oxo product. The reactive polyalkenes with an average molecular weight of about 500 to 5000 are homo- or copolymers of straight-chain or branched C ₂ -C ₃ n-alkenes, preferably C ₂ -C ₆ alkenes, in particular C ₂ -C alkenes. Reactive polyalkenes comprise unsaturated polymers of high chemical homogeneity, with more than 10% of the double bonds being alpha-permanent. One possibility for producing reactive polyalkenes is disclosed in DE-A-27 02 604. Those reactive polyalkenes which are prepared from 1-alkenes, such as in particular propylene, 1-butene, isobutene or mixtures thereof, are particularly preferred.

Suitable polyalkylamines of the general formula II are also amines according to EP-A-0 244 616 and EP-A-0 695 338, the content of which is hereby incorporated by reference. EP-A-0 244 616 describes in particular those polyalklamines in which the radical R ^{2 is} derived from isobutene and up to 20% by weight of n-butene. EP-A-0 695 338 describes in particular those polyalkylamines in which the radical R ^{2 is} derived from one or more 1-n-alkenes having 3 to 6 carbon atoms and up to 50% by weight of ethene.

Fuel compositions according to the invention include both diesel fuels and fuels for gasoline engines. Leaded and especially unleaded regular and premium gasoline are suitable as fuels for gasoline engines. The gasolines can also contain components other than hydrocarbons, e.g. B. alcohols, such as methanol, ethanol, tert-butanol, and ethers, for. B. methyl tert-butyl ether. In addition to the additives of the above formula I and optionally II, the fuel compositions according to the invention can contain further additive components.

Further additives which can be used according to the invention are described, for example, in European patent applications EP-A-0 277 345, 0 356 725, 0 476 485, 0 484 736, 0 539 821, 0 543 225, 0 548 617, 0 561 214, 0 567 810 and 0 568 873; in German patent applications DE-A-39 42 860, 43 09 074, 43 09 271, 43 13 088, 44 12 489, 44 25 834, 195 25 938, 196 06 845, 196 06 846, 196 15 404, 196 06 844, 196 16 569, 196 18 270 and 196 14 349; as well as in WO-A-96/03479.

Particularly useful liquid detergent additives are sold by BASF AG, Ludwigshafen, under the trade name Kerocom®PIBA. These contain polyisobutenamines dissolved in aliphatic Cj.o- ₁₄ - hydrocarbons.

In addition to the above additives, other customary fuel additives may also be present, such as corrosion inhibitors, demulsifiers, stabilizers, antioxidants, antistatic agents, metallocenes such as ferrocene or methylcyclopentadiene-manganese tricarbonyl, lubricity improvers and dyes (markers). Corrosion inhibitors are usually ammonium salts of organic carboxylic acids, which tend to form films due to the structure of the starting compounds. Amines for lowering the pH are also often found in corrosion inhibitors or can be added to the fuel as such. Heterocyclic aromatics are mostly used as non-ferrous metal corrosion protection.

Antioxidants or stabilizers include, in particular, amines such as para-phenylenediamine, dicyclohexylamine, morpholine or derivatives of these amines. Phenolic antioxidants such as 2, 4-di-tert. -butylphenol or 3, 5-di-tert. -butyl-4-hydroxiphenyl-propionic acid and its derivatives are added to fuels.

Salts of fatty and sulfonic acids are usually used as demulsifiers.

Examples of lubricity improvers are certain carboxylic acids or fatty acids, alkenyl succinic acid esters, bis (hydroxyalkyl) fatty amines; Hydroxyacetamide or castor oil. Suitable lubricity additives are e.g. B. described in EP-A-0 780 460, 0 829 527, 0 869 163, 0 605 857, WO 97/45507, 98/30658 and in US-A-5, 756,435 and 5,505,867, each of which is hereby expressly incorporated by reference becomes. The carboxylic acids or fatty acids mentioned can be present as monomers and / or dimeric species.

Furthermore, carrier oils can optionally be added, the carrier oils differing from the compounds of the formula I.

Examples of useful carrier oils or carrier liquids are mineral carrier oils, synthetic carrier oils and mixtures thereof which are compatible with the above additive (s) and the fuel. Suitable mineral carrier oils are fractions obtained in petroleum processing, such as kerosene or naphtha, brightstock or mineral oils with a viscosity in the range from SN 500 to 900; but also aromatic hydrocarbons, paraffinic hydrocarbons and alkoxyalkanols.

Examples of suitable synthetic carrier oils are polyolefins, (poly) esters, (poly) alkoxylates, and in particular aliphatic polyethers, aliphatic polyetheramines, alkylphenol-started polyethers and alkylphenol-started polyetheramines. Suitable carrier oil systems are described, for example, in DE-A-38 38 918, DE-A-38 26 608, DE-A-41 42 241, DE-A-43 09 074, US-A-4, 877, 416 and EP-A-0 452 328. Examples of particularly suitable synthetic carrier oils are alcohol-initiated polyethers with about 20 to 25 C ₃ -C ₆ alkylene oxide units, such as selected from propylene oxide, n-butylene oxide and i-butylene oxide units or mixtures thereof.

Examples of suitable additive combinations for fuels are combinations of at least one propoxylate according to formula I above, at least one detergent additive, such as. B. according to formula II above, at least one lubricity additive according to the above definition and / or optionally at least one corrosion inhibitor according to the above definition.

The present invention further relates to fuel additive mixtures which are preferably in the form of additive concentrates and at least one propoxylate additive of the formula I as defined above, in particular an alkanol propoxylate of the formula I above, optionally in combination with at least one polyalkylamine of the formula II, as the inlet valve cleaner component according to the above definition and optionally contain at least one other fuel additive. According to a preferred embodiment, the fuel additive mixtures according to the invention contain propoxylate and polyalkylamine in a molar ratio given above for the fuel compositions according to the invention.

Another object of the present invention relates to the use of at least one propoxylate of the above general formula I, optionally in combination with at least one detergent additive according to the above definition, in particular a polyalkylamine of the above general formula II, as an inlet valve cleaning wheel additive for fuel compositions for internal combustion engines.

The present invention will now be explained in more detail with the aid of the following examples.

Examples

Example 1: Engine test to test the effect as an intake system cleaner

The engine tests were carried out in an Opel Kadett 1.2 1 engine according to CEC F / 04 / A / 87. Fuel used: Euro-Super unleaded.

The additives used were manufactured according to the following general instructions. A dewatered mixture of the alcohol and KOH used as starter is placed in a pressure vessel, the amount of KOH used being about 0.01 to 1% by weight, preferably 0.05 to 0.5% by weight, of expected total weight of the reaction product. The apparatus is then flushed several times with nitrogen, heated to about 135 ° C. and the propylene oxide is then metered in with stirring at a constant temperature and a pressure between 3 and 30 bar via an immersion tube or onto the surface. After the metering has ended, the reaction mixture is stirred until the pressure is constant. After the reactor contents have cooled to about 50 ° C., the reaction vessel is let down and flushed with nitrogen. The product is freed from volatile constituents, advantageously in vacuo, and possibly clarified by filtration. Before the filtration, it is advantageous to remove the catalyst by methods known to the person skilled in the art, such as, for. B. treatment with ion exchanger, precipitation or adsorption, etc. carried out.

Table 1

5 ^χ) Values in brackets: deposits without additive; the different values are due to differences in the use of the Euro Super lead-free

_Q Example 2: Interaction of tridecanol propoxylate and polyisobutene amine

The following test results (engine: Mercedes Benz M 102 E) show that a maximum effect is also achieved with a tridecanol ₅ propoxylate with 15 moles of propylene oxide. In a fuel additive package containing polyisobutenamine (PIBA content 25% by weight), the carrier oil component was varied in the manner indicated.

Table 2

* Dosage of a formulation comprising propoxylate and PIBA in a weight ratio of about 1: 1; The total proportion of PIBA + propoxylate in the formulation is 50% by weight. 0

Example 3: Compatibility study

The following test results show that a tridecanol propoxylate with 15 moles of propylene oxide has optimal compatibility with the 5 components of an additive package (concentrate).

In a fuel additive package containing polyisobutenamine, the carrier oil component was replaced by the tridecanol propoxylate according to the invention with 15 moles of propylene oxide or by a corresponding propoxilate not in accordance with the invention with 25 moles of propylene oxide. The formulation with the component according to the invention was homogeneous, while in the comparative formulation a phase separation occurred when standing at 20 ° C.

35 58 / cb

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Claims

claims

1. A fuel composition for internal combustion engines, comprising a major amount of a liquid hydrocarbon fuel, characterized by a cleaning portion of at least one propoxylate additive of the formula I.

wherein

n stands for an integer value from 10 to 20 and

R ^{1 represents} a straight-chain or branched C ₈ -C ₁₈ alkyl or C ₈ -C ₁₈ alkenyl radical.

2. Fuel composition according to claim 1, characterized in that it contains the propoxylate of the formula I in a proportion of about 50 to 5000 mg / kg of fuel.

3. A fuel composition for internal combustion engines comprising a major amount of a liquid hydrocarbon fuel, characterized by a cleaning portion of an additive combination comprising

i) at least one propoxylate additive of the formula I according to claim 1; and

ii) at least one detergent additive;

optionally in combination with at least one lubricity improver.

4. The fuel composition according to claim 3, wherein the detergent additive is selected from polyalkylamine additives of the formula II

R ² -NH ₂ (II)

wherein R ^{2 represents} a straight-chain or branched polyalkyl radical with a number average molecular weight of about 500 to about 5000. 5

5. Fuel composition according to claim 3 or 4, characterized in that it contains the additives i) and ii) in a total proportion of about 100 to 10,000 mg / kg of fuel.

6. Fuel composition according to one of claims 3 to 5, characterized in that it contains the additives i) and ii) in a molar ratio of about 1:10 to about 10: 1.

7. Fuel composition according to one of claims 4 to 6, 15 characterized by at least one polyalkylamine additive

Formula II, wherein R ^{2 is} a radical derived from identical or different C ₂ -C ₃ o-alkenes.

8. Fuel composition according to one of claims 4 to 7, 20, characterized in that it contains, as an additive of formula II, at least one polyisobutenamine with a number average molecular weight of 800 to 1500.

9. Fuel composition according to one of the preceding claims, characterized in that it comprises at least one additive of the formula I, in which n stands for an integer value of 15 and R ^{1 stands} for a straight-chain or branched C ₃ alkyl radical.

10. Fuel additive mixture, characterized in that it contains at least one propoxylate as inlet valve cleaner components as defined in claim 1, optionally in combination with at least one detergent additive and optionally together with other customary fuel additives.

35

11. Fuel additive mixture according to claim 10, characterized in that it contains propoxylate and polyalkylamine in a molar ratio of about 1:10 to 10: 1.

40 12. Fuel additive mixture according to claim 10 or 11, characterized in that it comprises at least one lubricity improver as a further additive component.

13. Fuel additive mixture according to one of claims 10 to 12 45 assembled as an additive concentrate.

4. Use of at least one propoxylate as defined in claim 1, optionally in combination with at least one detergent additive as an inlet valve cleaner additive for fuel compositions for internal combustion engines.