Patent Description:
<CIT> discloses linear C<NUM>- to C<NUM>-amines as additives for reducing fouling of injectors in Diesel engines.

<CIT> discloses the use of hydrocarbyl amines wherein the hydrocarbyl moiety has a number average molecular weight in the range <NUM> to <NUM> as an additive for reducing injector nozzle fouling in a direct injection spark ignition engine.

Linear alkylamines are preferred, in the examples dodecyl amine (lauryl amine) was used.

<CIT> discloses a composition comprising amines and Mannich adducts as detergent for direct injection spark ignition engines.

Among other amines inter alia tridecyl amine is generically disclosed and used in one additive package without disclosing which isomer was used.

It is a disadvantage of linear amines that they tend to solidify at ambient temperatures so that incorporation of linear amines into additive packages requires a minimum temperature or heating of the components before mixing. Especially lauryl amine, as disclosed in <CIT>, is solid a room temperature and therefore needs to be molten before formulating an additive package. Furthermore, additive packages comprising lauryl amine as constituent show poor storage stability at low temperatures (see Comparative Examples below).

Furthermore, linear amines tend to demix from additive packages so that a higher amount of solvent or a stabiliser or compatibilizer is to be used as an additional component in order to yield stable mixtures.

It was an object of the present invention to develop amines as additives for unleaded gasoline fuels which exhibit an activity as an additive for reducing injector nozzle fouling comparable to the linear amines known from the prior art or even a higher activity but do not show their disadvantages but are easier to incorporate into an additive package. Furthermore, the storage stability of the amine-containing additive packages should be improved.

The problem was solved by the use of branched alkyl amine R-NH<NUM>, the alkyl group R having from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably <NUM> carbon atoms and with a branching of at least <NUM>, preferably of from <NUM> to <NUM>, more preferably from <NUM> to <NUM> as a fuel additive in unleaded gasoline.

Another object of the present invention are unleaded gasoline additive packages comprising at least one of these branched alkyl amines, at least one deposit control agent, and optionally further gasoline additives.

Another object of the present invention are unleaded gasoline fuel compositions comprising such additive packages. Such unleaded gasoline fuel compositions are preferably suitable for use in a spark ignition engine, for reducing injector nozzle fouling in a direct injection spark ignition engine.

Therefore, further object of the present invention are the use of branched primary alkyl amines R-NH<NUM>, the alkyl group R having from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably <NUM> carbon atoms and with a branching of at least <NUM>, preferably of from <NUM> to <NUM>, more preferably from <NUM> to <NUM> for reducing injector nozzle fouling in a direct injection spark ignition engine, the use of additive packages comprising such branched primary alkyl amines for reducing injector nozzle fouling in a direct injection spark ignition engine, and the use of an unleaded gasoline composition comprising a major proportion of a gasoline suitable for use in a spark ignition engine, for reducing injector nozzle fouling in a direct injection spark ignition engine.

The branched alkyl amines R-NH<NUM> according to the present invention are primary amines bearing an alkyl group R having from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably <NUM> carbon atoms, the alkyl group having a branching of at least <NUM>, preferably of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>.

"Branching" in the context of the present invention means that the alkyl residue R comprises the required number of branchings. In the case of a single amine with only one branched isomer the branching of that pure compound can be easily determined on the basis of the chemical structure. In case of isomer mixtures the average branching of the mixture is calculated by adding up the branching of each individual isomer multiplied by the molar amount of the respective isomer in the mixture. Preferably, the branching is determined using the branching index (ISO index) (see below).

The branched primary amines can be used as a mixture of amines of different molecular weight or preferably of one single molecular weight.

Typical examples of such amines are the branched isomers of octyl amine, nonyl amine, decyl amine, undecyl amine, dodecyl amine, tridecyl amine, tetradecyl amine, pentadecyl amine, hexadecyl amine, and heptadecyl amine, preferably nonyl amine, decyl amine, dodecyl amine, tridecyl amine, tetradecyl amine, hexadecyl amine, heptadecyl amine, eicosyl amine, docosyl amine, and mixtures thereof, more preferably nonyl amine, tridecyl amine, and heptadecyl amine, most preferably tridecyl amine and heptadecyl amine, and especially tridecyl amine. One preferred example for a branched octyl amine is <NUM>-amino-<NUM>,<NUM>,<NUM>-trimethyl-pentane.

One preferred example for a branched decyl amine is <NUM>-propylheptyl amine.

In a preferred embodiment the branched amines according to the present invention are obtainable by oligomerization of propene, isobutene, <NUM>-butene or <NUM>-butene forming a double bond-containing oligomer, followed by hydroformylation and reductive amination with ammonia. The resulting amine usually is a mixture of isomers.

In another preferred embodiment the branched amines according to the present invention are obtainable by amination of the corresponding branched alcohols or by reductive amination of the corresponding branched aldehydes. In this case the branching of the amines obtained is the same as that of the underlying alcohols or aldehydes, since the reaction conditions of the amination or reductive amination usually do not affect the branching of the alkyl group.

In the case of the branched tridecyl amine the mixture of isomers my contain one or more of the following isomers:
<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-Hexa methyl heptyl amine, <NUM>,<NUM>,<NUM>-tri ethyl heptyl amine, <NUM>,<NUM>,<NUM>,<NUM>,<NUM>-penta methyl octyl amine, heptyl amines bearing <NUM> ethyl groups and <NUM> methyl groups in position <NUM>, <NUM>, and <NUM>, and heptyl amines bearing <NUM> ethyl group and <NUM> methyl groups in position <NUM>, <NUM>, and <NUM>.

Isomer mixtures with <NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>-hexa methyl heptyl amine or <NUM>,<NUM>,<NUM>-tri ethyl heptyl amine as main constituents are most preferred.

Examples of mixtures of such branched amines are mixtures of tertiary alkyl C<NUM>- to C<NUM>-amines (<NPL>) or of C<NUM>- to C<NUM>-amines obtainable via Ritter reaction.

Amines with tertiary alkyl groups are less preferred since they exhibit a toxicity on inhalation. Hence, among the branched primary alkyl amines according to the invention those amines with the amine group bound to a primary carbon are preferred, i.e. amines bearing a group -CH<NUM>-NH<NUM>.

Especially preferred is a tridecylamine isomeric mixture from BASF SE (<NPL>) obtained by amination from the corresponding tridecanol isomeric mixture with a branching index of <NUM>.

Such branched alkyl amines exhibit a lower melting point than the corresponding linear alkyl amines and are, therefore, easier to formulate in additive packages. Often such branched alkyl amines are liquid at room temperature, however, usually exhibit a lower melting point than the corresponding linear isomers. With easier formulability is meant that less solvent is needed to achieve a homogenous formulation compared to the corresponding linear alkyl amines.

Therefore, it is an object of the present invention to use such branched primary alkyl amines R-NH<NUM>, the alkyl group R having from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably <NUM> carbon atoms and with a branching of at least <NUM>, preferably of from <NUM> to <NUM>, more preferably from <NUM> to <NUM> as an additive in a fuel additive package for improving the storage stability and/or formulability of fuel additive packages comprising.

for unleaded gasoline compositions suitable for use in a spark ignition engine, for reducing injector nozzle fouling in a direct injection spark ignition engine.

According to the invention the degree of branching is preferably described by the ISO index which indicates the average number of branches of the respective alkyl groups. Thus, for example, in the case of a C<NUM> alkyl group, the n-octyl group contributes <NUM>, methylheptyl groups contribute <NUM>, and dimethylhexyl groups contribute <NUM> to the ISO index. The lower the ISO index, the greater the linearity of the molecules in the respective group.

The degree of branching is defined as the number of methyl groups in a molecule of the amine minus <NUM>. The average degree of branching is the statistical average of the degree of branching of the molecules of a sample. The average degree of branching can be preferably determined by <NUM>H-NMR spectroscopy as follows: a sample of the amine is firstly subject to derivatization by means of trichloroacetyl isocyanate (TAI) (literature: <NPL>; <NPL>). The signals of the methylene group adjacent to the amino group are at δ = <NUM> to <NUM> ppm. All methyl, methylene and methine protons are in the range from <NUM> to <NUM> ppm. The signals < <NUM> ppm are assigned to the methyl groups. The average degree of branching (ISO index) can be calculated as follows from the spectrum obtained in this way: <MAT> where A(CH<NUM>) is the signal area corresponding to the methyl protons and A(CH<NUM>-NH<NUM>) is the signal area of the methylene protons in the CH<NUM>-NH<NUM> group. Primary amines bearing methine protons adjacent to the amino group (H<NUM>NCHR) may be analysed analogously. In the case of amines bearing a quaternary carbon atom adjacent to the amino group another distinct and assignable proton signal may be used for determining the ISO index.

In the case of branched amines obtained from the corresponding branched alcohols or aldehydes by amination or reductive amination the ISO index determined according to the above-mentioned method may be used.

An even more preferred <NUM>H-NMR method is handled without derivatization: The degree of branching (ISO index) of primary amines with no α-branching (H<NUM>NCH<NUM>R) is determined from their <NUM>H-NMR spectra. All NMR spectra were recorded at T = <NUM> on a Bruker Avance III <NUM> spectrometer operating at <NUM> for <NUM>H and <NUM> for <NUM>C. The spectrometer was equipped with a <NUM> z-gradient broadband observe smartprobe. Chemical shifts are referenced to Tetramethylsilane (TMS, δ(TMS) = <NUM> ppm). <NUM> 1D spectra were recorded using the zg pulse program with <NUM> data points, the relaxation delay D1 was chosen as <NUM> seconds, and <NUM> transients were recorded. For processing in Bruker TopSpin <NUM>. <NUM> software, <NUM> data points were used, an exponential window function with a line broadening of <NUM> was applied. Automatic baseline correction was used, phase correction was performed manually by the user. Phase sensitive HSQC spectra were recorded using the hsqcedetgpsisp2. <NUM> pulse sequence, with <NUM> data points in the direct and <NUM> data points in the indirect dimension using <NUM> transients per increment. Experiments were optimized for a <NUM>JC-H coupling constant of <NUM>. The relaxation delay D1 was set to <NUM>. For processing, <NUM> x <NUM> data points were Fourier transformed, and a quadratic sine function with a sine bell shift of <NUM> was applied.

Samples were prepared by dissolution of the pure analyte in deuterated chloroform with traces of TMS as internal reference. The samples were transferred into <NUM> NMR tubes. Deuterated solvents were purchased from Euriso-Top GmbH and used as received.

For the determination of the ISO index, the integral for H<NUM>NCH<NUM>R from δ = <NUM> - <NUM> ppm is set to a value of <NUM>. The signals of the aliphatic methyl groups (verified by phase-sensitive HSQC spectroscopy) are integrated from δ = <NUM> - <NUM> ppm giving the value I(Me). The degree of branching (ISO index) is calculated according to ISO index = I(Me)/<NUM> -<NUM>.

The unleaded gasoline additive packages respectively unleaded gasoline compositions according to the present invention comprise at least one deposit control agent, selected from the group consisting of.

Most preferably the deposit control agent is a polyalkenemono- or polyalkenepolyamines, especially a polyisobutene amine having a number average molecular weight in the range <NUM> to <NUM>.

The deposit control agents are described in more detail below:.

The at least one quaternary nitrogen component refer, in the context of the present invention, to nitrogen compounds quaternized in the presence of an acid or in an acid-free manner, preferably obtainable by addition of a compound comprising at least one oxygen- or nitrogen-containing group reactive with an anhydride and additionally at least one quaternizable amino group onto a polycarboxylic anhydride compound and subsequent quaternization.

In most cases the quaternary nitrogen component is an ammonium compound, however in the context of the present document morpholinium, piperidinium, piperazinium, pyrrolidinium, imidazolinium or pyridinium cations are also encompassed by the phrase "quaternary nitrogen component".

The quaternary ammonium compounds are preferably of the formula.

It is also possible that the anion may be multiply charged negatively, e.g. if anions of dibasic acids are used, in this case the stoichiometric ratio of the ammonium ions to the anions corresponds to the ratio of positive and negative charges.

The same is true for salts in which the cation bears more than one ammonium ion, e.g. of the substituents connect two or more ammonium ions.

In the organic residues the carbon atoms may be interrupted by one or more oxygen and/or sulphur atoms and/or one or more substituted or unsubstituted imino groups, and may be substituted by C<NUM>-C<NUM>-aryl, C<NUM>-C<NUM>-cycloalkyl or a five- or six-membered, oxygen-, nitrogen- and/or sulphur-containing heterocycle or two of them together form an unsaturated, saturated or aromatic ring which may be interrupted by one or more oxygen and/or sulphur atoms and/or one or more substituted or unsubstituted imino groups, where the radicals mentioned may each be substituted by functional groups, aryl, alkyl, aryloxy, alkyloxy, halogen, heteroatoms and/or heterocycles.

Two of the residues R<NUM> to R<NUM> may together form an unsaturated, saturated or aromatic ring, preferably a five-, six- or seven-membered ring (including the nitrogen atom of the ammonium ion).

In this case the ammonium cation may be a morpholinium, piperidinium, piperazinium, pyrrolidinium, imidazolinium or pyridinium cation.

If two radicals form a ring, they can together be <NUM>,<NUM>-propylene, <NUM>,<NUM>-butylene, <NUM>,<NUM>-pentylene, <NUM>-oxa-<NUM>,<NUM>-propylene, <NUM>-oxa-<NUM>,<NUM>-propylene, <NUM>-oxa-<NUM>,<NUM>-propylene, <NUM>-oxa-<NUM>,<NUM>-propenylene, <NUM>-aza-<NUM>,<NUM>-propenylene, <NUM>-C<NUM>-C<NUM>-alkyl-<NUM>-aza-<NUM>,<NUM>-propenylene, <NUM>,<NUM>-buta-<NUM>,<NUM>-dienylene, <NUM>-aza-<NUM>,<NUM>-buta-<NUM>,<NUM>-dienylene or <NUM>-aza-<NUM>,<NUM>-buta-<NUM>,<NUM>-dienylene.

The number of oxygen and/or sulphur atoms and/or imino groups is not subject to any restrictions. In general, there will be no more than <NUM> in the radical, preferably no more than <NUM> and very particularly preferably no more than <NUM>.

Furthermore, there is generally at least one carbon atom, preferably at least two carbon atoms, between any two heteroatoms.

Substituted and unsubstituted imino groups can be, for example, imino, methylimino, isopropy-limino, n-butylimino or tert-butylimino.

The residues R<NUM> to R<NUM> are preferably C<NUM>-C<NUM>-alkyl or C<NUM>-C<NUM>-aryl, more preferably C<NUM>-C<NUM>-alkyl or C<NUM>-C<NUM>-aryl, and even more preferably C<NUM>-C<NUM>-alkyl or C<NUM>-aryl.

The residues R<NUM> to R<NUM> may be saturated or unsaturated, preferably saturated.

Preferred residues R<NUM> to R<NUM> do not bear any heteroatoms other than carbon or hydrogen.

Preferred examples of R<NUM> to R<NUM> are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, <NUM>-ethylhexyl, <NUM>,<NUM>,<NUM>-trimethylpentyl, <NUM>-propylheptyl, decyl, dodecyl, tetradecyl, heptadecyl, octadecyl, eicosyl, <NUM>,<NUM>-dimethylpropyl, <NUM>,<NUM>-dimethylbutyl, <NUM>,<NUM>,<NUM>,<NUM>-tetramethylbutyl, benzyl, <NUM>-phenylethyl, <NUM>-phenylethyl, α,α-dimethylbenzyl, benzhydryl, p-tolylmethyl or <NUM>-(p-butylphenyl)ethyl.

In a preferred embodiment at least one of the residues R<NUM> to R<NUM> is selected from the group consisting of <NUM>-hydroxyethyl, hydroxyprop-<NUM>-yl, hydroxyprop-<NUM>-yl, <NUM>-hydroxybutyl or <NUM>-hydroxy-<NUM>-phenylethyl.

In one embodiment R<NUM> is a polyolefin-homo- or copolymer, preferably a polypropylene, polybutene or polyisobutene residue, with a number-average molecular weight (Mn) of <NUM> to <NUM>, for example <NUM> to <NUM><NUM>, or <NUM> to <NUM> or <NUM> to <NUM>, for example <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>. Preferred are polypropenyl, polybutenyl and polyisobutenyl radicals, for example with a number-average molecular weight Mn of <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM> and <NUM> to <NUM>/mol.

Preferred examples of anions A- are the anions of acetic acid, propionic acid, butyric acid, <NUM>-ethylhexanoic acid, trimethylhexanoic acid, <NUM>-propylheptanoic acid, isononanoic acid, versatic acids, decanoic acid, undecanoic acid, dodecanoic acid, saturated or unsaturated fatty acids with <NUM> to <NUM> carbon atoms, or mixtures thereof, salicylic acid, oxalic acid mono-C<NUM>-C<NUM>-alkyl ester, phthalic acid mono-C<NUM>-C<NUM>-alkyl ester, C<NUM>-C<NUM>-alkyl- and -alkenyl succinic acid, especially dodecenyl succinic acid, hexadecenyl succinic acid, eicosenyl succinic acid, and polyisobutenyl succinic acid. Further examples are methyl carbonate, ethyl carbonate, n-butyl carbonate, <NUM>-hydroxyethyl carbonate, and <NUM>-hydroxypropyl carbonate.

In one preferred embodiment the nitrogen compounds quaternized in the presence of an acid or in an acid-free manner are obtainable by addition of a compound which comprises at least one oxygen- or nitrogen-containing group reactive with an anhydride and additionally at least one quaternizable amino group onto a polycarboxylic anhydride compound and subsequent quaternization, especially with an epoxide, e.g. styrene or propylene oxide, in the absence of free acid, as described in <CIT>, or with a carboxylic ester, e.g. dimethyl oxalate or methyl salicylate. Suitable compounds having at least one oxygen- or nitrogen-containing group reactive with anhydride and additionally at least one quaternizable amino group are especially polyamines having at least one primary or secondary amino group and at least one tertiary amino group, especially N,N-dimethyl-<NUM>,<NUM>-propane diamine, N,N-dimethyl-<NUM>,<NUM>-ethane diamine or N,N, N'-trimethyl-<NUM>,<NUM>-ethane diamine. Useful polycarboxylic anhydrides are especially dicarboxylic acids such as succinic acid, having a relatively long-chain hydrocarbyl substituent, preferably having a number-average molecular weight Mn for the hydrocarbyl substituent of <NUM> to <NUM>, in particular of <NUM> to <NUM>. Such a quaternized nitrogen compound is, for example, the reaction product, obtained at <NUM>, of polyisobutenylsuccinic anhydride, in which the polyisobutenyl radical typically has an Mn of <NUM>, with <NUM>-(dimethylamino)propylamine, which constitutes a polyisobutenylsuccinic monoamide and which is subsequently quaternized with dimethyl oxalate or methyl salicylate or with styrene oxide or propylene oxide in the absence of free acid.

Further quaternized nitrogen compounds suitable as compounds are described in.

In one embodiment the quaternized ammonium compound is of formula
<CHM>
wherein in this formula.

In another preferred embodiment the quaternized ammonium compound is of formula
<CHM>
wherein in this formula.

In another embodiment the quaternized compound is of formula
<CHM>
wherein in this formula.

In another embodiment the quaternized ammonium compound is of formula
<CHM>
wherein in this formula.

Typical Mannich adducts are described in <CIT>, preferred are Mannich adducts according to formula I of <CIT>, which are incorporated by reference to the present document.

In a preferred embodiment the Mannich adducts are obtainable as described in <CIT>, column <NUM>, line <NUM> to column <NUM>, line <NUM>.

Preferably the Mannich adducts are obtainable by reaction of.

more preferably selected from the group consisting of dimethylamine, diethylamine, di-n-butylamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, N, N-dimethylpropylene- <NUM>, <NUM>-diamine, and N, N-diethylpropylene- <NUM>, <NUM>-diamine.

The hydrocarbyl residue of the at least one hydrocarbyl-substituted phenol preferably has a number average molecular weight Mn of from <NUM> to <NUM>, preferably of from <NUM> to <NUM>, more preferably of from <NUM> to <NUM>, and especially from <NUM> to <NUM>.

In a preferred embodiment the hydrocarbyl residue is a polyisobutene radical of the before-mentioned molecular weight, more preferably derived from a "reactive" polyisobutene radical as defined in <CIT>.

In a preferred embodiment the Mannich adduct is of formula
<CHM>
or of formula
<CHM>
wherein.

Polyalkenemono- or polyalkenepolyamines are preferably based on polypropene or on high-reactivity (i.e. having predominantly terminal double bonds) or conventional (i.e. having predominantly internal double bonds) polybutene or especially polyisobutene with Mn = <NUM> to <NUM>, more preferably <NUM> to <NUM> and especially <NUM> to <NUM>. Such additives based on high-reactivity polyisobutene, which can be prepared from the polyisobutene which may comprise up to <NUM>% by weight of n-butene units by hydroformylation and reductive amination with ammonia, monoamines or polyamines such as dimethylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine, are known especially from <CIT>. When polybutene or polyisobutene having predominantly internal double bonds (usually in the β and γ positions) are used as starting materials in the preparation of the additives, a possible preparative route is by chlorination and subsequent amination or by oxidation of the double bond with air or ozone to give the carbonyl or carboxyl compound and subsequent amination under reductive (hydrogenating) conditions. The amines used here for the amination may be, for example, ammonia, monoamines or the abovementioned polyamines. Corresponding additives based on polypropene are described more particularly in <CIT>.

Further particular additives comprising monoamino groups are the hydrogenation products of the reaction products of polyisobutenes having an average degree of polymerization P = <NUM> to <NUM> with nitrogen oxides or mixtures of nitrogen oxides and oxygen, as described more particularly in <CIT>.

Further particular additives comprising monoamino groups are the compounds obtainable from polyisobutene epoxides by reaction with amines and subsequent dehydration and reduction of the amino alcohols, as described more particularly in <CIT>.

Examples of particularly useful polyalkylene radicals are polyisobutenyl radicals derived from what are called "high-reactivity" polyisobutenes which feature a high content of terminal double bonds. Terminal double bonds are alpha-olefinic double bonds of the type
<CHM>
which are also referred to collectively as vinylidene double bonds. Suitable high-reactivity polyisobutenes are, for example, polyisobutenes which have a proportion of vinylidene double bonds of greater than <NUM> mol%, especially greater than <NUM> mol% or greater than <NUM> mol%. Preference is given especially to polyisobutenes which have homogeneous polymer skeletons. Homogeneous polymer skeletons are possessed especially by those polyisobutenes formed from isobutene units to an extent of at least <NUM>% by weight, preferably to an extent of at least <NUM>% by weight and more preferably to an extent of at least <NUM>% by weight. Such high-reactivity polyisobutenes preferably have a number-average molecular weight within the abovementioned range. In addition, the high-reactivity polyisobutenes may have a polydispersity in the range from <NUM> to <NUM>, especially of about <NUM> to <NUM>, for example of less than <NUM> or less than <NUM>. Polydispersity is understood to mean the quotient of weight-average molecular weight Mw divided by the number-average molecular weight Mn.

Particularly suitable high-reactivity polyisobutenes are, for example, the Glissopal brands from BASF SE, especially Glissopal® <NUM> (Mn = <NUM>), Glissopal® V <NUM> (Mn = <NUM>) and Glissopal® <NUM> (Mn = <NUM>), and mixtures thereof. Other number-average molecular weights can be established in a manner known in principle by mixing polyisobutenes of different number-average molecular weights or by extractive enrichment of polyisobutenes of particular molecular weight ranges.

Due to their high proportion of vinylidene double bonds these polyisobutenes are especially reactive to undergo hydroformylation and subsequent amination, preferably with ammonia, to yield the corresponding polyisobutene amines, which represent a preferred embodiment of the present invention.

As corrosion inhibitors in principle all compounds known in the art for application in fuels may be used.

Suitable corrosion inhibitors are, for example, succinic esters or hemiesters, in particular with polyols, fatty acid derivatives, for example oleic esters, oligomerized fatty acids, such as dimeric fatty acid, substituted ethanolamines, and products sold under the trade name RC <NUM> (Rhein Chemie Mannheim, Germany) or HiTEC <NUM> (Afton Corporation).

According to <CIT> the latter is believed to be a reaction product of linear or branched alkyl or alkenyl substituted succinic anhydride with substituted amino-imidazolines resulting in what are believed to be linear or branched alkyl or alkenyl substituted succinimide or amine substituted succinimides.

In a preferred embodiment the corrosion inhibitor is selected from the group consisting of.

In a more preferred embodiment the corrosion inhibitor is selected from the group consisting of.

The succinic acids, esters or hemiesters are preferably substituted with C<NUM>- to C<NUM>-alkyl or -alkenyl radicals.

In a preferred embodiment the succinic acids or hemiesters follow formula
<CHM>
wherein.

The underlying succinic acid anhydrides are obtainable by thermal ene reaction of C<NUM>- to C<NUM>-alkenes, preferably oligomers or polymers of propene, <NUM>-butene or isobutene, with maleic anhydride. The above-mentioned corrosion inhibitors are obtainable from such anhydrides by hydrolysis or reaction with the appropriate alcohol.

The olefin-carboxylic acid copolymer (A) is a copolymer obtainable by.

The monomer (Aa) is at least one, preferably one to three, more preferably one or two and most preferably exactly one ethylenically unsaturated, preferably α,β-ethylenically unsaturated, mono- or dicarboxylic acid(s) or derivatives thereof, preferably a dicarboxylic acid or derivatives thereof.

Preferably, the derivatives are anhydrides in monomeric form or di-C<NUM>-C<NUM>-alkyl esters, more preferably anhydrides in monomeric form.

In the context of this document, C<NUM>-C<NUM>-alkyl is understood to mean methyl, ethyl, iso-propyl, n-propyl, n-butyl, iso-butyl, sec-butyl and tert-butyl, preferably methyl and ethyl, more preferably methyl.

Examples of α,β-ethylenically unsaturated mono- or dicarboxylic acids are those mono- or dicarboxylic acids or derivatives thereof in which the carboxyl group or, in the case of dicarboxylic acids, at least one carboxyl group, preferably both carboxyl groups, is/are conjugated to the ethylenically unsaturated double bond.

Examples of ethylenically unsaturated mono- or dicarboxylic acids that are not α,β-ethylenically unsaturated are cis-<NUM>-norbornene-endo-<NUM>,<NUM>-dicarboxylic anhydride, exo-<NUM>,<NUM>-epoxy-<NUM>,<NUM>,<NUM>,<NUM>-tetrahydrophthalic anhydride and cis-<NUM>-cyclohexene-<NUM>,<NUM>-dicarboxylic anhydride.

Examples of α,β-ethylenically unsaturated monocarboxylic acids are acrylic acid, methacrylic acid, crotonic acid and ethylacrylic acid, preferably acrylic acid and methacrylic acid, referred to in this document as (meth)acrylic acid for short, and more preferably acrylic acid.

Particularly preferred derivatives of α,β-ethylenically unsaturated monocarboxylic acids are methyl acrylate, ethyl acrylate, n-butyl acrylate and methyl methacrylate.

Examples of dicarboxylic acids are maleic acid, fumaric acid, itaconic acid (<NUM>-methylenebutanedioic acid), citraconic acid (<NUM>-methylmaleic acid), glutaconic acid (pent-<NUM>-ene-<NUM>,<NUM>-dicarboxylic acid), <NUM>,<NUM>-dimethylmaleic acid, <NUM>-methylfumaric acid, <NUM>,<NUM>-dimethylfumaric acid, methylenemalonic acid and tetrahydrophthalic acid, preferably maleic acid and fumaric acid and more preferably maleic acid and derivatives thereof.

More particularly, monomer (Aa) is maleic anhydride.

Monomer (Ab) is at least one, preferably one to four, more preferably one to three, even more preferably one or two and most preferably exactly one α-olefin(s) having from at least <NUM> up to and including <NUM> carbon atoms. The α-olefins (Ab) preferably have at least <NUM>, more preferably at least <NUM> and most preferably at least <NUM> carbon atoms. Preferably, the α-olefins (Ab) have up to and including <NUM>, more preferably up to and including <NUM> and most preferably up to and including <NUM> carbon atoms.

Preferably, the α-olefins may be one or more linear or branched, preferably linear, <NUM>-alkene.

Examples of these are <NUM>-dodecene, <NUM>-tridecene, <NUM>-tetradecene, <NUM>-pentadecene, <NUM>-hexadecene, <NUM>-heptadecene, <NUM>- octadecene, <NUM>-nonodecene, <NUM>-eicosene, <NUM>-docosene, <NUM>-tetracosene, <NUM>-hexacosene, preference being given to <NUM>-octadecene, <NUM>-eicosene, <NUM>-docosene and <NUM>-tetracosene, and mixtures thereof.

Further examples of α-olefin (Ab) are those olefins which are oligomers or polymers of C<NUM> to C<NUM> olefins, preferably of C<NUM> to C<NUM> olefins, more preferably of C<NUM> to C<NUM> olefins. Examples thereof are ethene, propene, <NUM>-butene, <NUM>-butene, isobutene, pentene isomers and hexene isomers, preference being given to ethene, propene, <NUM>-butene, <NUM>-butene and isobutene.

Named examples of α-olefins (Ab) include oligomers and polymers of propene, <NUM>-butene, <NUM>-butene, isobutene, and mixtures thereof, particularly oligomers and polymers of propene or isobutene or of mixtures of <NUM>-butene and <NUM>-butene. Among the oligomers, preference is given to the trimers, tetramers, pentamers and hexamers, and mixtures thereof.

In addition to the olefin (Ab), it is optionally possible to incorporate at least one, preferably one to four, more preferably one to three, even more preferably one or two and especially exactly one further aliphatic or cycloaliphatic olefin(s) (Ac) which has/have at least <NUM> carbon atoms and is/are different than (Ab) by polymerization into the inventive copolymer.

The olefins (Ac) may be olefins having a terminal (α-)double bond or those having a non-terminal double bond, preferably having an α-double bond. The olefin (Ac) preferably comprises olefins having <NUM> to fewer than <NUM> or more than <NUM> carbon atoms. If the olefin (Ac) is an olefin having <NUM> to <NUM> carbon atoms, this olefin (Ac) does not have an α-double bond.

Examples of aliphatic olefins (Ac) are <NUM>-butene, <NUM>-butene, isobutene, pentene isomers, hexene isomers, heptene isomers, octene isomers, nonene isomers, decene isomers, undecene isomers and mixtures thereof.

Examples of cycloaliphatic olefins (Ac) are cyclopentene, cyclohexene, cyclooctene, cyclode-cene, cyclododecene, α- or β-pinene and mixtures thereof, limonene and norbornene.

Further examples of olefins (Ac) are polymers having more than <NUM> carbon atoms of propene, <NUM>-butene, <NUM>-butene or isobutene or of olefin mixtures comprising the latter, preferably of isobutene or of olefin mixtures comprising the latter, more preferably having a mean molecular weight Mw in the range from <NUM> to <NUM>/mol, preferably <NUM> to <NUM> and more preferably <NUM> to <NUM>/mol.

Preferably, the oligomers or polymers comprising isobutene in copolymerized form have a high content of terminal ethylenic double bonds (α-double bonds), for example at least <NUM> mol%, preferably at least <NUM> mol%, more preferably at least <NUM> mol% and most preferably at least <NUM> mol%.

For the preparation of such oligomers or polymers comprising isobutene in copolymerized form, suitable isobutene sources are either pure isobutene or isobutene-containing C4 hydrocarbon streams, for example C4 raffinates, especially "raffinate <NUM>", C4 cuts from isobutane dehydrogenation, C4 cuts from steamcrackers and from FCC crackers (fluid catalyzed cracking), provided that they have substantially been freed of <NUM>,<NUM>-butadiene present therein. A C4 hydrocarbon stream from an FCC refinery unit is also known as a "b/b" stream. Further suitable isobutene-containing C4 hydrocarbon streams are, for example, the product stream of a propylene-isobutane cooxidation or the product stream from a metathesis unit, which are generally used after customary purification and/or concentration. Suitable C4 hydrocarbon streams comprise generally less than <NUM> ppm, preferably less than <NUM> ppm, of butadiene. The presence of <NUM>-butene and of cis- and trans-<NUM>-butene is substantially uncritical. Typically, the isobutene concentration in said C4 hydrocarbon streams is in the range from <NUM>% to <NUM>% by weight. For instance, raffinate <NUM> generally consists essentially of <NUM>% to <NUM>% by weight of isobutene, <NUM>% to <NUM>% by weight of <NUM>-butene, <NUM>% to <NUM>% by weight of cis- and trans-<NUM>-butene and <NUM>% to <NUM>% by weight of butanes; in the polymerization process the unbranched butenes in the raffinate <NUM> are generally virtually inert, and only the isobutene is polymerized.

In a preferred embodiment, the monomer source used for polymerization is a technical C4 hydrocarbon stream having an isobutene content of <NUM>% to <NUM>% by weight, especially of <NUM>% to <NUM>% by weight, in particular of <NUM>% to <NUM>% by weight, more preferably of <NUM>% to <NUM>% by weight, especially a raffinate <NUM> stream, a b/b stream from an FCC refinery unit, a product stream from a propylene-isobutane cooxidation or a product stream from a metathesis unit.

Especially when a raffinate <NUM> stream is used as isobutene source, the use of water as the sole initiator or as further initiator has been found to be useful, particularly when polymerization is effected at temperatures of -<NUM> to +<NUM>, especially of <NUM> to +<NUM>. At temperatures of - <NUM> to +<NUM>, especially of <NUM> to +<NUM>, however, it is possible to dispense with the use of an initiator when using a raffinate <NUM> stream as isobutene source.

Said isobutene-containing monomer mixture may comprise small amounts of contaminants such as water, carboxylic acids or mineral acids without causing any critical yield or selectivity losses. It is appropriate to the purpose to avoid accumulation of these impurities by removing such harmful substances from the isobutene-containing monomer mixture, for example, by adsorption on solid adsorbents such as activated carbon, molecular sieves or ion exchangers.

It is also possible, albeit less preferable, to convert monomer mixtures of isobutene or of the isobutene-containing hydrocarbon mixture with olefinically unsaturated monomers copolymerizable with isobutene. If monomer mixtures of isobutene with suitable comonomers are to be copolymerized, the monomer mixture comprises preferably at least <NUM>% by weight, more preferably at least <NUM>% by weight and especially at least <NUM>% by weight of isobutene, and preferably at most <NUM>% by weight, more preferably at most <NUM>% by weight and especially at most <NUM>% by weight of comonomers.

In a preferred embodiment, the mixture of the olefins (Ab) and optionally (Ac), averaged to their molar amounts, have at least <NUM> carbon atoms, preferably at least <NUM>, more preferably at least <NUM> and most preferably at least <NUM> carbon atoms.

For example, a <NUM>:<NUM> mixture of docosene and tetradecene has an averaged value for the carbon atoms of <NUM> × <NUM> + <NUM> × <NUM> = <NUM>.

The upper limit is less relevant and is generally not more than <NUM> carbon atoms, preferably not more than <NUM>, more preferably not more than <NUM>, even more preferably not more than <NUM> and especially not more than <NUM> carbon atoms.

The optional monomer (Ad) is at least one monomer, preferably one to three, more preferably one or two and most preferably exactly one monomer(s) selected from the group consisting of.

Examples of vinyl esters (Ada) are vinyl esters of C<NUM>- to C<NUM>-carboxylic acids, preferably vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pentanoate, vinyl hexanoate, vinyl octanoate, vinyl <NUM>-ethylhexanoate, vinyl decanoate, and vinyl esters of Versatic Acids <NUM> to <NUM>, preferably vinyl esters of <NUM>,<NUM>-dimethylpropionic acid (pivalic acid, Versatic Acid <NUM>), <NUM>,<NUM>-dimethylbutyric acid (neohexanoic acid, Versatic Acid <NUM>), <NUM>,<NUM>-dimethylpentanoic acid (neoheptanoic acid, Versatic Acid <NUM>), <NUM>,<NUM>-dimethylhexanoic acid (neooctanoic acid, Versatic Acid <NUM>), <NUM>,<NUM>-dimethylheptanoic acid (neononanoic acid, Versatic Acid <NUM>) or <NUM>,<NUM>-dimethyloctanoic acid (neodecanoic acid, Versatic Acid <NUM>).

Examples of vinyl ethers (Adb) are vinyl ethers of C<NUM>- to C<NUM>-alkanols, preferably vinyl ethers of methanol, ethanol, iso-propanol, n-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-hexanol, n-heptanol, n-octanol, n-decanol, n-dodecanol (lauryl alcohol) or <NUM>-ethylhexanol.

Preferred (meth)acrylic esters (Adc) are (meth)acrylic esters of C<NUM>- to C<NUM>-alkanols, preferably of n-pentanol, n-hexanol, n-heptanol, n-octanol, n-decanol, n-dodecanol (lauryl alcohol), <NUM>-ethylhexanol or <NUM>-propylheptanol. Particular preference is given to pentyl acrylate, <NUM>-ethylhexyl acrylate, <NUM>-propylheptyl acrylate.

Examples of monomers (Add) are allyl alcohols and allyl ethers of C<NUM>- to C<NUM>-alkanols, preferably allyl ethers of methanol, ethanol, iso-propanol, n-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-hexanol, n-heptanol, n-octanol, n-decanol, n-dodecanol (lauryl alcohol) or <NUM>-ethylhexanol.

Examples of vinyl compounds (Ade) of heterocycles comprising at least one nitrogen atom are N-vinylpyridine, N-vinylimidazole and N-vinylmorpholine.

Preferred compounds (Ade) are N-vinylamides or N-vinyllactams.

Examples of N-vinylamides or N-vinyllactams (Ade) are N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone and N-vinylcaprolactam.

Examples of ethylenically unsaturated aromatics (Adf) are styrene and α-methylstyrene.

Examples of α,β-ethylenically unsaturated nitriles (Adg) are acrylonitrile and methacrylonitrile.

Examples of (meth)acrylamides (Adh) are acrylamide and methacrylamide.

Examples of allylamines (Adi) are allylamine, dialkylallylamine and trialkylallylammonium halides.

Preferred monomers (Ad) are (Ada), (Adb), (Adc), (Ade) and/or (Adf), more preferably (Ada), (Adb) and/or (Adc), even more preferably (Ada) and/or (Adc) and especially (Adc).

The incorporation ratio of the monomers (Aa) and (Ab) and optionally (Ac) and optionally (Ad) in the polymer obtained from reaction step (I) is generally as follows:
The molar ratio of (Aa)/((Ab) and (Ac)) (in total) is generally from <NUM>:<NUM> to <NUM>:<NUM>, preferably <NUM>:<NUM> to <NUM>:<NUM>, more preferably <NUM>:<NUM> to <NUM>:<NUM>, even more preferably <NUM>:<NUM> to <NUM>:<NUM>, particularly <NUM>:<NUM> to <NUM>:<NUM> and especially <NUM>:<NUM> to <NUM>:<NUM>. In the preferred particular case of maleic anhydride as monomer (Aa), the molar incorporation ratio of maleic anhydride to monomers ((Ab) and (Ac)) (in total) is about <NUM>:<NUM>.

The molar ratio of obligatory monomer (Ab) to monomer (Ac), if present, is generally of <NUM>:<NUM> to <NUM>, preferably of <NUM>:<NUM> to <NUM>, more preferably of <NUM>:<NUM> to <NUM>, even more preferably of <NUM>:<NUM> to <NUM> and especially <NUM>:<NUM> to <NUM>.

In a preferred embodiment, no optional monomer (Ac) is present in addition to monomer (Ab).

The proportion of one or more of the monomers (Ad), if present, based on the amount of the monomers (Aa), (Ab) and optionally (Ac) (in total) is generally <NUM> to <NUM> mol%, preferably <NUM> to <NUM> mol%, more preferably <NUM> to <NUM> mol%, even more preferably <NUM> to <NUM> mol% and especially <NUM> to <NUM> mol%.

In a preferred embodiment, no optional monomer (Ad) is present.

In a second reaction step (II), the anhydride or carboxylic ester functionalities present in the copolymer obtained from (I) are partly or fully hydrolyzed and/or saponified.

Reaction step (II) is obligatory in case the copolymer obtained from reaction step (I) does not comprise free carboxylic acid groups.

Hydrolization of anhydride groups is preferred over saponification of ester groups.

Preferably, <NUM>% to <NUM>% of the anhydride or carboxylic ester functionalities present are hydrolyzed and/or saponified, preferably at least <NUM>%, more preferably at least <NUM>%, even more preferably at least <NUM>% and particularly at least <NUM>% and especially at least <NUM>%.

For a hydrolysis, based on the anhydride functionalities present, the amount of water that corresponds to the desired hydrolysis level is added and the copolymer obtained from (I) is heated in the presence of the added water. In general, a temperature of preferably <NUM> to <NUM> is sufficient for the purpose, preferably <NUM> to <NUM>. If required, the reaction can be conducted under pressure in order to prevent the escape of water. Under these reaction conditions, in general, the anhydride functionalities in the copolymer are converted selectively, whereas any carboxylic ester functionalities present in the copolymer react at least only to a minor degree, if at all.

For a saponification, the copolymer is reacted with an amount of a strong base corresponding to the desired saponification level in the presence of water.

Strong bases used may preferably be hydroxides, oxides, carbonates or hydrogencarbonates of alkali metals or alkaline earth metals.

The copolymer obtained from (I) is then heated in the presence of the added water and the strong base. In general, a temperature of preferably <NUM> to <NUM> is sufficient for the purpose, preferably <NUM> to <NUM>. If required, the reaction can be conducted under pressure.

It is also possible to hydrolyze the carboxylic ester functionalities with water in the presence of an acid. Acids used are preferably mineral acids, carboxylic acids, sulfonic acids or phosphorus acids having a pKa of not more than <NUM>, more preferably not more than <NUM>.

Examples are acetic acid, formic acid, oxalic acid, salicylic acid, substituted succinic acids, aromatically substituted or unsubstituted benzenesulfonic acids, sulfuric acid, nitric acid, hydrochloric acid or phosphoric acid; the use of acidic ion exchange resins is also conceivable.

In a preferred embodiment for anhydrides, especially maleic anhydride being monomers (Aa), such anhydride moieties are partly or fully, especially fully hydrolysed while potentially existing ester groups in the copolymer remain intact. In this case no saponification in step (II) takes place.

The copolymer obtained from (I) is then heated in the presence of the added water and the acid. In general, a temperature of preferably <NUM> to <NUM> is sufficient for the purpose, preferably <NUM> to <NUM>. If required, the reaction can be conducted under pressure.

Should the copolymers obtained from step (II) still comprise residues of acid anions, it may be preferable to remove these acid anions from the copolymer with the aid of an ion exchanger and preferably exchange them for hydroxide ions or carboxylate ions, more preferably hydroxide ions. This is the case especially when the acid anions present in the copolymer are halides or contain sulfur or nitrogen.

The copolymer obtained from reaction step (II) generally has a weight-average molecular weight Mw of <NUM> to <NUM> kDa, preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>, even more preferably <NUM> to <NUM> and especially <NUM> to <NUM> kDa (determined by gel permeation chromatography with tetrahydrofuran and polystyrene as standard).

The number-average molecular weight Mn is usually from <NUM> to <NUM> kDa, preferably <NUM> to <NUM>, more preferably <NUM> to <NUM>, even more preferably <NUM> to <NUM> and especially <NUM> to <NUM> kDa (determined by gel permeation chromatography with tetrahydrofuran and polystyrene as standard).

The polydispersity is generally from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, even more preferably from <NUM> to <NUM> and especially from <NUM> to <NUM>.

The content of acid groups in the copolymer is preferably from <NUM> to <NUM> mmol/g of copolymer, more preferably from <NUM> to <NUM>, even more preferably from <NUM> to <NUM> mmol/g of copolymer.

In a preferred embodiment, the copolymers comprise a high proportion of adjacent carboxylic acid groups, which is determined by a measurement of adjacency. For this purpose, a sample of the copolymer is heat-treated between two Teflon films at a temperature of <NUM> for a period of <NUM> minutes and an FTIR spectrum is recorded at a bubble-free site. The IR spectrum of Teflon is subtracted from the spectra obtained, the layer thickness is determined and the content of cyclic anhydride is determined.

In a preferred embodiment, the adjacency is at least <NUM>%, preferably at least <NUM>%, more preferably at least <NUM>%, even more preferably at least <NUM>% and especially at least <NUM>%.

The olefin-carboxylic acid copolymer (A) is applied in the form of the free acid, i.e. COOH groups are present, or in the form of the anhydride which may be an intramolecular anhydride or an intermolecular anhydride linking two dicarboxylic acid molecules together, preferably in the form of a free acid. To a minor extent, some of the carboxylic functions may be present in salt form, e.g. as alkali or alkaline metal salts salts or as ammonium or substituted ammonium salts, depending on the pH value of the liquid phase. Preferably at least <NUM> % of all carboxylic acid groups are available in the form of the free acid as COOH-groups, more preferably at least <NUM> %, very preferably at least <NUM> %, even more preferably at least <NUM> %, and especially at least <NUM>%. A single olefin-carboxylic acid copolymer (A) or a mixture of different olefin-carboxylic acid copolymers (A) may be used.

Carrier oils additionally used may be of mineral or synthetic nature. Suitable mineral carrier oils are fractions obtained in crude oil processing, such as brightstock or base oils having viscosities, for example, from the SN <NUM> - <NUM> class; but also aromatic hydrocarbons, paraffinic hydrocarbons and alkoxyalkanols. Likewise useful is a fraction which is obtained in the refining of mineral oil and is known as "hydrocrack oil" (vacuum distillate cut having a boiling range of from about <NUM> to <NUM>, obtainable from natural mineral oil which has been catalytically hydrogenated under high pressure and isomerized and also deparaffinized). Likewise suitable are mixtures of the abovementioned mineral carrier oils.

Examples of suitable synthetic carrier oils are polyolefins (polyalphaolefins or polyinternalolefins), (poly)esters, (poly)alkoxylates, polyethers, aliphatic polyetheramines, alkylphenol-started polyethers, alkylphenol-started polyetheramines and carboxylic esters of long-chain alkanols.

Examples of suitable polyolefins are olefin polymers having Mn = <NUM> to <NUM>, in particular based on polybutene or polyisobutene (hydrogenated or unhydrogenated).

Examples of suitable polyethers or polyetheramines are preferably compounds comprising polyoxy-C<NUM>- to C<NUM>-alkylene moieties obtainable by reacting C<NUM>- to C<NUM>-alkanols, C<NUM>- to C<NUM>-alkanediols, mono- or di-C<NUM>- to C<NUM>-alkylamines, C<NUM>- to C<NUM>-alkylcyclohexanols or C<NUM>- to C<NUM>-alkylphenols with <NUM> to <NUM> mol of ethylene oxide and/or propylene oxide and/or butylene oxide per hydroxyl group or amino group, and, in the case of the polyetheramines, by subsequent reductive amination with ammonia, monoamines or polyamines. Such products are described more particularly in <CIT>, <CIT>, <CIT> and <CIT>. For example, the polyetheramines used may be poly-C<NUM>- to C<NUM>-alkylene oxide amines or functional derivatives thereof. Typical examples thereof are tridecanol butoxylates or isotridecanol butoxylates, isononylphenol butoxylates and also polyisobutenol butoxylates and propoxylates, and also the corresponding reaction products with ammonia.

Examples of carboxylic esters of long-chain alkanols are more particularly esters of mono-, di- or tricarboxylic acids with long-chain alkanols or polyols, as described more particularly in <CIT>. The mono-, di- or tricarboxylic acids used may be aliphatic or aromatic acids; particularly suitable ester alcohols or ester polyols are long-chain representatives having, for example, <NUM> to <NUM> carbon atoms. Typical representatives of the esters are adipates, phthalates, isophthalates, terephthalates and trimellitates of isooctanol, isononanol, isodecanol and isotridecanol, for example di(n- or isotridecyl) phthalate.

Further suitable carrier oil systems are described, for example, in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

Examples of particularly suitable synthetic carrier oils are alcohol-started polyethers having about <NUM> to <NUM>, preferably about <NUM> to <NUM>, more preferably <NUM> to <NUM> and especially <NUM> to <NUM> C<NUM>- to C<NUM>-alkylene oxide units, for example propylene oxide, n-butylene oxide and isobutylene oxide units, or mixtures thereof, per alcohol molecule. Nonlimiting examples of suitable starter alcohols are long-chain alkanols or phenols substituted by long-chain alkyl in which the long-chain alkyl radical is especially a straight-chain or branched C<NUM>- to C<NUM>-alkyl radical. Particular examples include tridecanol, heptadecanol and nonylphenol. Particularly preferred alcohol-started polyethers are the reaction products (polyetherification products) of monohydric aliphatic C<NUM>- to C<NUM>-alcohols with C<NUM>- to C<NUM>-alkylene oxides. Examples of monohydric aliphatic C<NUM>-C<NUM>-alcohols are hexanol, heptanol, octanol, <NUM>-ethylhexanol, nonyl alcohol, decanol, <NUM>-propylheptanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol and the constitutional and positional isomers thereof. The alcohols can be used either in the form of the pure isomers or in the form of technical grade mixtures. A particularly preferred alcohol is tridecanol. Examples of C<NUM>- to C<NUM>-alkylene oxides are propylene oxide, such as <NUM>,<NUM>-propylene oxide, butylene oxide, such as <NUM>,<NUM>-butylene oxide, <NUM>,<NUM>-butylene oxide, isobutylene oxide or tetrahydrofuran, pentylene oxide and hexylene oxide. Particular preference among these is given to C<NUM>- to C<NUM>-alkylene oxides, i.e. propylene oxide such as <NUM>,<NUM>-propylene oxide and butylene oxide such as <NUM>,<NUM>-butylene oxide, <NUM>,<NUM>-butylene oxide and isobutylene oxide. Especially butylene oxide is used.

Further suitable synthetic carrier oils are alkoxylated alkylphenols, as described in <CIT>.

Particular carrier oils are synthetic carrier oils, particular preference being given to the above-described alcohol-started polyethers.

Typical other additives in the additive packages or fuels according to the invention may be friction modifier, dehazers, antioxidants, metal deactivators, and solvents for the packages.

Suitable friction modifiers are based typically on fatty acids or fatty acid esters. Typical examples are tall oil fatty acid, as described, for example, in <CIT>, and glyceryl monooleate. The reaction products, described in <CIT>, of natural or synthetic oils, for example triglycerides, and alkanolamines are also suitable as such friction modifier.

Preferred lubricity improvers are described in <CIT> and <CIT>. Furthermore, hydroxyl group-substituted tertiary amines as disclosed in <CIT> are preferred as friction modifiers.

Suitable dehazer are, for example, the alkali metal or alkaline earth metal salts of alkylsubstituted phenol- and naphthalenesulfonates and the alkali metal or alkaline earth metal salts of fatty acids, and also neutral compounds such as alcohol alkoxylates, e.g. alcohol ethoxylates, phenol alkoxylates, e.g. tert-butylphenol ethoxylate or tert-pentylphenol ethoxylate, fatty acids, alkylphenols, condensation products of ethylene oxide (EO) and propylene oxide (PO), for example including in the form of EO/PO block copolymers, polyethyleneimines or else polysiloxanes.

Further suitable dehazers are EO/PO-based alkoxylates of alkylphenol-formaldehyde condensates (Novolac, resol or calixarene type), EO/PO-based alkoxylates of diols (e.g. propandiol, ethylene glycole), triols (e.g. glycerol or trimethylolpropane), ethylene diamine, or polyethyleneimine. Further suitable dehazers are alkybenzene sulfonic acids, dialkylsulfosuccinates or alkali metal or ammonium salts thereof. Suitable dehazers are described in <CIT>. Further suitable dehazers based on diglycidyl ethers are described in <CIT> and <CIT>.

Other suitable dehazers are, for example, alkoxylated phenol-formaldehyde condensates, for example the products available under the trade names NALCO 7D07 (Nalco) and TOLAD <NUM> (Petrolite).

Suitable antioxidants are, for example, substituted phenols, such as <NUM>,<NUM>-di-tert-butylphenol, <NUM>,<NUM>-di-tert-butyl-<NUM>-methyl phenol, <NUM>,<NUM>-di-tert-butyl-<NUM>-methylphenol, preferably hindered phenols with an ester group bearing radical in paraposition, such as <NUM>-[<NUM>,<NUM>-bis-(dimethylethyl)-<NUM>-hydroxyphenyl] propanoic acid C<NUM>- to C<NUM>-alkyl esters, e.g. <NUM>-ethylhexyl- or stearylester, and also phenylenediamines such as N,N'-di-sec-butyl-p-phenylenediamine.

Suitable metal deactivators are, for example, salicylic acid derivatives such as N,N'-disalicylidene-<NUM>,<NUM>-propanediamine.

Suitable solvents are, for example, nonpolar organic solvents such as aromatic and aliphatic hydrocarbons, for example toluene, xylenes, white spirit and products sold under the trade names SHELLSOL (Royal Dutch/Shell Group) and EXXSOL (ExxonMobil), and also polar organic solvents, for example, alcohols such as <NUM>-ethylhexanol, <NUM>-propylheptanol, decanol, isotridecanol and isoheptadecanol. Such solvents are usually added to the fuel together with the aforementioned additives and coadditives, which they are intended to dissolve or dilute for better handling.

Therefore, another object of the present invention is a fuel additive package for gasoline fuels, comprising.

Preferably the at least one further gasoline fuel additive is selected from the group consisting of corrosion inhbitors, carrier oils, and solvents.

It is an advantage of the present invention that the amount of solvents in the additive packages can be reduced by the use of the branched alkyl amines compared to the use of linear alkyl amines.

In the context of the present invention, gasoline fuels mean liquid hydrocarbon distillate fuels boiling in the gasoline range. It is in principle suitable for use in all types of gasoline, including "light" and "severe" gasoline species. The gasoline fuels may also contain amounts of other fuels such as, for example, ethanol.

Typically, gasoline fuels, which may be used according to the present invention exhibit, in addition, one or more of the following features:
The aromatics content of the gasoline fuel is preferably not more than <NUM> volume % and more preferably not more than <NUM> volume %. Preferred ranges for the aromatics content are from <NUM> to <NUM> volume % and particularly from <NUM> to <NUM> volume %.

The sulfur content of the gasoline fuel is preferably not more than <NUM> ppm by weight and more preferably not more than <NUM> ppm by weight. Preferred ranges for the sulfur content are from <NUM> to <NUM> ppm by weight and particularly from <NUM> to <NUM> ppm by weight.

The gasoline fuel has an olefin content of not more than <NUM> volume %, preferably not more than <NUM> volume %, and more preferably not more than <NUM> volume %. Preferred ranges for the olefin content are from <NUM> to <NUM> volume % and particularly from <NUM> to <NUM> volume %.

The gasoline fuel has a benzene content of not more than <NUM> volume % and preferably not more than <NUM> volume %. Preferred ranges for the benzene content are from <NUM> to <NUM> volume % and preferably from <NUM> to <NUM> volume %.

The gasoline fuel has an oxygen content of not more than <NUM> weight %, preferably from <NUM> to <NUM> weight %, and most preferably from <NUM> to <NUM> weight % (first type) or most preferably from <NUM> to <NUM> weight % (second type). The gasoline fuel of the second type mentioned above is a mixture of lower alcohols such as methanol or especially ethanol, which derive preferably from natural source like plants, with mineral oil based gasoline, i.e. usual gasoline produced from crude oil. An example for such gasoline is "E <NUM>", a mixture of <NUM> volume % of ethanol with <NUM> volume % of mineral oil based gasoline. Also a fuel containing <NUM> % of a lower alcohol, especially ethanol, is suitable.

The amount of alcohols and ethers contained in the gasoline may vary over wide ranges. Typical maximum contents are e.g. methanol <NUM>% by volume, ethanol <NUM>% by volume, isopropanol <NUM>% by volume, tert-butanol <NUM>% by volume, isobutanol <NUM>% by volume and ethers containing <NUM> or more carbon atoms in the molecule <NUM>% by volume.

The summer vapor pressure of the gasoline fuel is usually not more than <NUM> kPa and preferably not more than <NUM> kPa (at <NUM>).

The research octane number ("RON") of the gasoline fuel is usually from <NUM> to <NUM>. A usual range for the corresponding motor octane number ("MON") is from <NUM> to <NUM>.

The above characteristics are determined by conventional methods (DIN EN <NUM>).

Therefore, another object of the present invention is an unleaded gasoline composition suitable for use in a spark ignition engine for reducing injector nozzle fouling in a direct injection spark ignition engine, comprising.

Another object of the present invention is an unleaded gasoline composition suitable for use in a spark ignition engine for reducing injector nozzle fouling in a direct injection spark ignition engine, comprising.

Another object of the present invention is a fuel additive package for unleaded gasoline fuels for reducing injector nozzle fouling in a direct injection spark ignition engine, comprising.

Preferably the at least one further unleaded gasoline fuel additive is selected from the group consisting of corrosion inhbitors, carrier oils, and solvents.

The unleaded gasoline fuels according to the present invention comprise said at least one branched alkyl amine in an amount of from <NUM> to <NUM> ppm, preferably from <NUM> to <NUM> ppm, more preferably from <NUM> to <NUM> ppm, most preferably from <NUM> to <NUM> ppm.

The deposit control agent or mixture of a plurality of such additives is present in the unleaded gasoline fuels in the case of polyalkenemono- or polyalkenepolyamines or Mannich adducts typically in an amount of from <NUM> to <NUM> ppm by weight, preferably of from <NUM> to <NUM> ppm by weight, more preferably of from <NUM> to <NUM> ppm by weight (based on the gasoline composition).

In the case of quaternary ammonium compounds as deposit control agents they are typically present in the unleaded gasoline fuels in an amount of from <NUM> to <NUM> ppm by weight, preferably of from <NUM> to <NUM> ppm by weight (based on the gasoline composition).

The one or more corrosion inhibitors, if any, are present in the unleaded gasoline fuels normally in an amount of from <NUM> to <NUM> ppm by weight, preferably of from <NUM> to <NUM> ppm by weight, more preferably of from <NUM> to <NUM> ppm by weight, most preferably of from <NUM> to <NUM> ppm by weight, for example of from <NUM> to <NUM> ppm by weight.

The one or more carrier oils, if any, are present in the unleaded gasoline fuels normally in an amount of form <NUM> to <NUM> ppm by weight, preferably of from <NUM> to <NUM> ppm by weight, more preferably of from <NUM> to <NUM> ppm by weight, most preferably of from <NUM> to <NUM> ppm by weight.

One or more dehazers as additive component, if any, are present in the unleaded gasoline fuels generally in an amount of from <NUM> to <NUM> ppm by weight, preferably of from <NUM> to <NUM> ppm by weight, more preferably of from <NUM> to <NUM> ppm by weight, most preferably of from <NUM> to <NUM> ppm by weight, for example of from <NUM> to <NUM> ppm by weight.

The other additive components described above each, if any, are present in the unleaded gasoline fuels generally in an amount of from <NUM> to <NUM> ppm by weight, preferably of from <NUM> to <NUM> ppm by weight, more preferably of from <NUM> to <NUM> ppm by weight, most preferably of from <NUM> to <NUM> ppm by weight.

Subject matter of the present invention is also a fuel additive concentrate suitable for use in unleaded gasoline fuels comprising.

The amounts given throughout the text refer to the pure components excluding e.g. solvent, unless stated otherwise.

The test method is a preliminary version of the upcoming CEC test for injector fouling in DISI engines (TDG-F-<NUM>) and was published by <NPL>. The test engine is a VW EA111 <NUM> TSI engine with <NUM> kW. The test procedure is a steady state test at an engine speed of <NUM> rpm and a constant torque of <NUM>.

The test procedure is performed with the following injectors: Magneti Marelli 03C <NUM><NUM> E. Reference oil RL-<NUM> from Haltermann Carless was used as engine oil.

In the dirty-up-clean-up sequence dirty-up is achieved by running the engine over <NUM> hours as described for the keep-clean procedure (see above) with base fuel. The relative change of activation time is determined as described above for the keep-clean test. The subsequent clean-up run is done with additized base fuel over <NUM>. At the end of the test <NUM> data points are determined within <NUM> minutes, which mean value gives the activation time at end of clean-up test. The test result for the clean-up is the relative change of activation time of the injectors relative to the aver-age activation time determined at the end of the dirty-up phase.

The test was run with an EN <NUM> compliant low sulfur Haltermann DISI TSI fuel according to CEC RF-<NUM> mod complying with EN <NUM>.

The dirty-up phase used fuel without additive and was run for <NUM> hours, the clean-up phase using additized fuel for <NUM> hours.

In Run <NUM> the fuel contained <NUM>/kg PIBA* and <NUM>/kg linear dodecylamin.

In Run <NUM> the fuel contained <NUM>/kg PIBA* and <NUM>/kg branched tridecylamin obtained by amination from the corresponding tridecanol isomeric mixture with a branching index of <NUM> determined following the above-mentioned procedure.

Nozzle coking is measured as change of activation time of the injector (ti_I), which is measured periodically within the test procedure. Due to nozzle coking, the hole diameters of the injector holes are reduced, and the activation time adjusted by the Engine Control Unit (ECU) accordingly. The activation time in milliseconds is a direct readout from the ECU via ECU control software. A prolongation of activation time is an indicator for nozzle coking. The test duration was <NUM>.

After a run-in period of <NUM> minutes <NUM> data points for ti_I were determined within <NUM> minutes, which mean value gives the activation time at start of test. At the end of the test <NUM> data points were determined within <NUM> minutes, which mean value gives the activation time at end of test. The test result is the relative change of activation time ti_I of the injectors.

It can easily be seen that the additive package comprising the branched alkyl amine according to the invention shows at least the same activity in reducing injector nozzle fouling as the linear dodecyl amine according to the prior art, if not even an improved activity.

Three gasoline performance packages were formulated according to the following table. The carrier fluid used is a propoxylated tridecanol derived from trimerbutene (after hydroformylation and hydrogenation). Clear formulations were obtained in both cases.

All three formulations were stored at <NUM>, room temperature and -<NUM> for one week to evaluate their storage stability.

It can easily be seen that Comparative Formulation <NUM> using the same weight composition of the components as Formulation <NUM> according to the invention exhibits a much worse storage stability than Formulation <NUM>.

Claim 1:
Use of branched primary alkyl amine R-NH<NUM>, the alkyl group R having from <NUM> to <NUM>, preferably from <NUM> to <NUM>, more preferably <NUM> carbon atoms and with a branching of at least <NUM> determined by <NUM>H-NMR spectroscopy, preferably of from <NUM> to <NUM>, more preferably from <NUM> to <NUM> as a fuel additive in an unleaded gasoline composition suitable for use in a spark ignition engine, for reducing injector nozzle fouling in a direct injection spark ignition engine.