Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
/I
s
Lubricity improver and a fuel and lubricant compositions
containing said agent
The present invention relates to additive mixtures, their use for
improving the lubricity of fuels and for improving the wear
resistance of engines and to fuel compositions and additive
packages containing them and their use as lubricant additives.
Carburetors and intake systems of gasoline engines as well as
injection systems for fuel metering are increasingly becoming
contaminated with impurities which are caused by dust particles
from the air, uncombusted hydrocarbon residues from the
combustion chamber and the crankcase vent gases passed into the
carburetor.
These residues shift the air/fuel ration during idling and in the
lower part-load range so that the mixture becomes leaner, the
combustion more incomplete and hence the amounts of uncombusted
or partially combusted hydrocarbons in the exhaust gas become
larger, resulting in increased gasoline consumption.
It is known that these disadvantages are avoided by using fuel
additives for keeping valves and carburetors or injection systems
of gasoline engines clean (cf. for example: M. Rossenbeck in
Katalysatoren, Tenside, Mineraloladditive, Editors J. Falbe and
U. Hasserodt, page 223, G. Thieme Verlag, Stuttgart 1978).
Depending on the mode of action, but also the preferred site of
action of such detergent additives, a distinction is now made
between two generations.
The first generation of additive could only prevent the formation
of deposits in the intake system but were unable to remove
existing deposits, whereas the modern additives of the second
generation can do both (keep-clean and clean-up effect) and,
owing to their excellent thermal stability, can do so in
particular in zones of high temperature, i.e. at the intake
valves.
Such detergents which may originate from a large number of
classes of chemical substances, for example polyalkenylamines,
polyetheramines, polybutene Mannich bases or
polybutenylsuccinamides, are used in general in combination with
carrier oils and, if required, further additive components, for
example corrosion inhibitors and demulsifiers. Gasoline fuels
with and without such gasoline fuel additives exhibit different
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behavior with respect to their lubricity and wear properties in
gasoline engines, which however is unsatisfactory and should
therefore be improved.
5 In contrast to fuel additives for diesel fuels, in which
components for improving the lubricity of diesel fuels are part
of the prior art, in the case of gasoline fuels there are only a
few technical solutions for significantly increasing and hence
improving the lubricity of gasoline fuels by adding suitable
10 additives to them. For example, it is known that fatty acids and
derivatives thereof, (EP-A-780 460, EP-A- 829 527),
alkenylsuccinic esters (WO 97/45507), bis(hydroxyalkyl)-fatty
amines (EP-A-869 163) or hydroxyacetamides (WO-98/30658,
US-A-5,756,435) when used as additives for gasoline fuels and/or
15 gasoline fuel additives, can improve the lubricity of the
gasoline fuels. In the case of castor oil, too, it is known that
its addition to diesel fuels
(EP-A-605 857) and/or gasoline fuels (US-A-5,505,867) can
increase the lubricity.
It is an object of the present invention to provide novel fuel
additives which improve the lubricity, in particular of gasoline
fuels, or the wear resistance, in particular of gasoline engines.
We have found that this object is achieved, surprisingly, by
providing additive mixtures, in particular gasoline fuel additive
mixtures, containing, as a lubricity additive, a mixture of
a) at least one reaction product of a dicarboxylic acid or of a
dicarboxylic acid derivative with a long-chain, aliphatic
amine of, for example, up to 30 carbon atoms, the reaction
product comprising a compound of the following formula I:
O
C - R1
R (I)
\C - Rz
4o II
0
where
R is a saturated or unsaturated Cz-C4-bridging group
which is unsubstituted or mono- or polysubstituted,
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R1 is NR3R4, where
R3 and R4 are identical or different and are each a
straight-chain or branched aliphatic radical selected
from C8-C2o-alkyl, mono- or polyunsaturated
Ce-C2o-alkenyl, C8-CZO-alkyloxy, and mono- or
polyunsaturated C8-C2o-alkenyloxy, or one of the
radicals R3 and R4 is H and the other radical is an
aliphatic radical according to the above definition,
and
R2 is OH or O-NR5R6 + where
R5 and R6, independently of one another and
independently of R3 and R4, have the meanings stated
for R3 and R4, and
b) at least one fatty ester or one fatty ester-containing
component.
The two components are present in a volume ratio of from about
1:10 to 10:1, in particular from about 1:5 to 5:1.
In a first preferred embodiment, additive mixtures according to
the above definition are provided, where R is CZ-C4-alkylene or
ethenylene. Suitable substituents on R are, for example,
hydroxyl, C1-C4-alkyl, such as methyl and ethyl, and
hydroxy-C1-C4-alkyl, such as hydroxymethyl and hydroxyethyl.
Examples of suitable dicarboxylic acid derivatives which can be
used for the preparation of compounds of the formula I are in.
particular the cyclic dicarboxylic anhydrides. Preferred
anhydrides are malefic anhydride and succinic anhydride and the
corresponding substituted analogs thereof. Further preferred
dicarboxylic acid derivatives are dicarboxylic esters, in
particular esters of C1-Clo-monools, C1-Clo-monools being defined
as stated below for the fatty esters.
Preferred meanings of R3, R4, R5 and R6 in compounds of the
formula I are C8-C2o-alkyl, e.g. n-octyl, n-nonyl, n-decyl,
n-undecyl, n-tridecyl, n-tetradecyl, n-pentadecyl and
n-hexadecyl, and the singly and multiply branched analogs
thereof .
Examples of suitable Ce-C2o-alkenyl radicals are the mono- or
polyunsaturated, preferably monounsaturated analogs of the
abovementioned alkyl radicals, it being possible for the double
bond to be in any desired position of the carbon chain. Examples
of suitable C$-CZO-alkyloxy and C$-C2o-alkenyloxy radicals are the
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oxygen-terminated analogs of the abovementioned alkyl and alkenyl
radicals.
Preferred long-chain aliphatic amines which are used for the
reaction with the dicarboxylic acid or the dicarboxylic acid
derivative are primary or secondary amines having one or two
identical or different CB-C2o-alkyl or alkenyl radicals, in
particular decylamine, undecylamine, dodecylamine, tridecylamine,
tetradecylamine, pentadecylamine and hexadecylamine, and the
corresponding secondary amines having two identical aliphatic
radicals. Further examples are fatty amines and fatty amine
mixtures, for example those of 16 to 18 carbon atoms.
Suitable fatty esters are synthesized from straight-chain or
branched, mono- or polyunsaturated, unsubstituted or substituted
C6-C3a-monocarboxylic acids and a monohydric or polyhydric,
preferably monohydric to trihydric, alcohol. Polyhydric alcohols
may be partially or completely esterified with the same or
another fatty acid. Examples of saturated straight-chain fatty
acids are caproic acid, enanthic acid, caprylic acid, pelargonic
acid, capric acid, undecanoic acid, lauric acid, tridecanoic
acid, myristic acid, pentadecanoic acid, palmitic acid, margaric
acid, stearic acid, nonadecanoic acid, arachidic acid, behenic
acid, lignoceric acid, cerotic acid and melissic acid. Examples
of monounsaturated fatty acids are palmitoleic acid, oleic acid
and erucic acid. Examples of diunsaturated fatty acids are sorbic
acid and linoleic acid. Examples of triunsaturated fatty acids
are linolenic and eleostearic acid. Examples of fatty acids which
are tetraunsaturated or have a higher degree of unsaturation are
arachidonic acid, clupanodonic acid and docosahexaenoic acid. An
example of a substituted fatty acid is ricinoleic acid
((R)-12-hydroxy-(Z)-9-octadecenoic acid). Further suitable fatty
acids are naturally occurring fatty acids, such as gondoic acid
and neronic acid. If the fatty acids contain double bonds, they
may be present both in the cis and in the trans form. The
substituents are preferably selected from hydroxyl and lower
alkyl groups, e.g. methyl and ethyl. Furthermore, keto or epoxy
groups, as in vernolic acid, may be present in the hydrocarbon
radical. Further functional groups are cyclopropane, cyclopropene
and cyclopentene rings, which may be formed by bridging two
neighboring carbon atoms in the hydrocarbon radical of the fatty
acid (cf. malvalic acid and chaulmoogric acid).
Examples of suitable alcohols are C1-Clo-monools, in particular
methanol, ethanol, n-propanol, n-butanol, n-pentanol and the
corresponding branched analogs thereof. Examples of suitable
diols are CZ-C6-diols, such as ethane-1,2-diol, propane-1,3-diol,
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butane-1,2-diol and pentane-1,2-diol and the corresponding
positional isomers of these diols. Examples of suitable alcohols
having a higher functionality are in particular glycerol and
sugar alcohols, e.g. sorbitol and inositol, pentaerythritol and
5 trimethylol propane. A preferred polyhydric alcohol is glycerol.
A preferred group of fatty esters comprises triglycerides of
identical or different fatty acids according to the above
definition or mixtures of such triglycerides and mixtures of such
triglycerides with the corresponding mono- and/or diglycerides.
Natural triglycerides as are to be found, for example, in
vegetable oils are particularly preferably used. Examples of
particularly suitable vegetable oils are rapeseed oil, coconut
oil, palm kernel oil, corn oil, olive oil, soybean oil, sunflower
oil, linseed oil, peanut oil and castor oil. The triglycerides
which can be used according to the invention can be isolated from
these oils. If permitted by the triglyceride content of such
oils, they can also be added directly to the novel additive
compositions. For example, industrial castor oil can be used
without further fractionation in the novel additive mixtures.
The present invention furthermore relates to the use of the novel
additive mixtures for improving the lubricity of gasoline fuels
and/or for improving the wear resistance of gasoline engines. The
present invention also relates to fuel compositions, in
particular for gasoline engines, containing a lubricity-improving
amount of at least one additive mixture according to the present
invention, if required in combination with further conventional
fuel additives, in addition to a main amount of a hydrocarbon
fuel. The present invention furthermore relates to additive
concentrates containing a novel additive mixture in combination
-- with further conventional additive components in solid or, if
desired, dissolved or dispersed forms.
Surprisingly, it has been found that the wear of gasoline engines
can be substantially reduced using fuels to which the novel fuel
additives have been added. It has been possible to show that a
synergistic effect is obtained by the novel combination of the
reaction products of dicarboxylic acids or their derivatives of
long-chain, aliphatic amines and natural fatty esters.
The reaction product of dicarboxylic acids or their derivatives
with long-chain, aliphatic amines according to the formula
defined above, as a component of the novel fuel additives, is
obtained directly with the use of known processes (cf.
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Houben-Weyl, VIII, page 656, X/2, page 747; or J. March, Advanced
Organic Chemistry, 3rd edition, 1985, page 371).
Preferred synergistic combinations comprise reaction products of
carboxylic anhydrides with primary or secondary alkyl- or
alkenylamines mixed with triglycerides. Mixtures of reaction
products of malefic anhydride with primary or secondary
alkylamines having a chain length of C8-C18, e.g. tridecylamine or
ditridecylamine, and castor oil are particularly preferred.
The novel additive mixture can be used alone or in combination
with further fuel additives, for example the abovementioned
detergent additives described in more detail below.
Examples of further gasoline fuel additives (having a detergent
action) which are used in addition to the novel fuel additives
are those which have at least one hydrophobic hydrocarbon radical
having a number average molecular weight (Mn) of from 85 to 20,000
and at least one polar group which is selected from
(a) mono- or polyamino groups having up to 6 nitrogen atoms, at
least one nitrogen atom having basic properties,
(b) nitro groups, if required 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) sulfo groups or their alkali metal or alkaline earth metal
salts,
(f) polyoxy-C2-C4-alkylene groups which are terminated by hydroxyl
groups or by mono- or polyamino groups, at least one nitrogen
atom having basic properties, or by carbamate groups,
(g) carboxylic ester groups,
(h) groups derived from succinic anhydride and having hydroxyl
and/or amino and/or amido and/or imido groups and
(i) groups produced by Mannich reaction of phenolic hydroxyl
groups with aldehydes and mono- or polyamines.
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The hydrophobic hydrocarbon radical in these detergent additives,
which ensures sufficient solubility in the fuel, has a number
average molecular weight (Mn) of from 85 to 20,000, in particular
from 113 to 10,000, especially from 300 to 5000. Suitable typical
hydrophobic hydrocarbon radicals, in particular in combination
with the polar groups (a), (c), (h) and (i), are the
polypropenyl, polybutenyl and polyisobutenyl radicals, each
having an Mn of from 150 to 5000, in particular from 500 to 2500,
especially from 750 to 2250.
Examples of fuel additives having polar groups (a) are
polyalkenyl monoamines or polyalkenyl polyamines or functional
derivatives thereof, in particular poly-C2-C6-alkenylamines or
functional derivatives thereof, for example based on polypropene,
polybutene or polyisobutene. Additives containing mono- or
polyamino groups (a) are preferably polyalkenyl monoamines or
polyalkenylpolyamines based on polypropene or on highly reactive
(i.e. having predominantly terminal double bonds, generally in
the a- and ~- positions) or conventional (i.e. having
predominantly central double bonds) polybutene or polyisobutene
having an Mn of from 150 to 5000, preferably from about 500 to
2000, in particular from about 800 to 1500 g. Such additives
based on highly reactive polyisobutene which can be prepared from
polyisobutene, which may contain up to 20% 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 disclosed in particular in EP-A-244
616 or EP-A-0 578 323. If polybutene or polyisobutene having
predominantly central double bonds (generally in the ~- and
y-positions) is used as a starting material in the preparation of
the additives, a possible method of preparation 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 same amines as those used above for the reductive
amination of the hydroformylated highly reactive polyisobutene
may be employed here for the amination. Corresponding additives
based on polypropene are described in particular in
WO-A 94/24231.
Further preferred additives containing monoamino groups (a) are
the hydrogenation products of the reaction products of
polyisobutenes having an average degree of polymerization P of
from 5 to 100 with oxides of nitrogen or mixtures of oxides of
nitrogen and oxygen, as described in particular in WO-A 97/03946.
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8
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 described in particular in DE-A 196 20 262.
Additives containing nitro groups, if desired in combination with
hydroxyl groups, (b) are preferably reaction products of
polyisobutenes having an average degree of polymerization P of
from 5 to 100 or from 10 to 100 with oxides of nitrogen or
mixtures of oxides of nitrogen and oxygen, as described in
particular in WO-A 96/03367 and in WO-A 96/03479. These reaction
products are as a rule mixtures of pure nitropolyisobutanes (e. g.
a,~-dinitropolyisobutane) and mixed hydroxynitropolyisobutanes
(e. g. a-nitro-~-hydroxypolyisobutane).
Additives containing hydroxyl groups in combination with mono- or
polyamino groups (c) are in particular reaction products of
polyisobutene epoxides, obtainable from polyisobutene having
preferably predominantly terminal double bonds and an Mn of from
150 to 5000, with ammonia, or mono- or polyamines, as described
in particular in EP-A 476 485.
Additives containing carboxyl groups or their alkali metal or
alkaline earth metal salts (d) are preferably copolymers of
C2-CQO-olefins with malefic anhydride, having a total molar mass of
from 500 to 20,000, some or all of whose carboxyl groups having
been converted into the alkali metal or alkaline earth metal
salts and the remainder of whose carboxyl groups having been
reacted with alcohols or amines. Such additives are disclosed in
particular in EP-A 307 815. Such additives serve mainly for
preventing 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)butenylamines or polyetheramines.
Additives containing sulfo groups or their alkali metal or
alkaline earth metal salts (e) are preferably alkali metal or
alkaline earth metal salts of an alkyl sulfosuccinate, as
described in particular in EP-A-639 632. Such additives serve
mainly for preventing valve seat wear and can advantageously be
used in combination with conventional fuel detergents, such as
poly(iso)butenylamines or polyetheramines.
Additives containing polyoxy-C2-C4-alkylene groups (f) are
preferably polyethers or polyetheramines, which are obtainable by
reacting C2-C6o-alkanols, C6-C3o-alkanediols, mono- or
di-C2-C3o-alkylamines, C1-C3o-alkylcyclohexanols or
C1-C3o-alkylphenols with from 1 to 30 mol of ethylene oxide and/or
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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 in particular in EP-A-310 875, EP-A-356
725, EP-A-700 985 and US-A-4,877,416. For example
poly-C2-C6-alkylene oxide amines or functional derivatives thereof
can be used as polyetheramines. In the case of polyethers, such
products also have carrier oil properties. Typical examples of
these are tridecanol butoxylates, isotridecanol butoxylates,
isononylphenol butoxylates and polyisobuteneol butoxylates and
progoxylates and the corresponding reaction products with
ammonia.
Additives containing carboxylic ester groups (g) are preferably
esters of mono- di- or tricarboxylic acids with long-chain
alkanols or polyols, in particular those having a minimum
viscosity of 2 mm2/s at 100~C, as described in particular in
DE-A-38 38 918. The mono-, di- or tricarboxylic acids used may be
aliphatic or aromatic acids, and suitable ester alcohols and
ester polyols are in particular long-chain members having, for
example, 6 to 24 carbon atoms. Typical esters are adipates,
phthalates, isophthalates, terephthalates and trimellitates of
isooctanol, of isononanol, of isodecanol and of isotridecanol.
Such products also have carrier oil properties.
Additives containing groups which are derived from succinic
anhydride and have hydroxyl and/or amino and/or amido and/or
imido groups (h) are preferably corresponding derivatives of
polyisobutenylsuccinic anhydride, which are obtainable by
reacting conventional or highly reactive polyisobutene having an
Mn of from 150 to 5000 with malefic anhydride by a thermal route or
via the chlorinated polyisobutene. Of particular interest here
are derivatives with aliphatic polyamines, such as
ethylenediamine, diethylenetriamine, triethylenetetramine or
tetraethylenepentamine. 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, diethyletriamine, triethylenetetramine,
tetraethylenepentamine or dimethylaminopropylamine. The
polyisobutene-substituted phenols may originate from conventional
or highly reactive polyisobutene having an Mn of from 150 bis
CA 02391932 2002-05-15
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5000. Such polyisobutene Mannich bases are described in
particular in EP-A 831 141.
Further detergent additives suitable according to the invention
are described, for example in EP-A-0 277 345, EP-A-0 484 736,
EP-A-0 539 821, EP-A-0 543 225, EP-A-0 548 617, EP-A-0 561 214,
EP-A-0 567 810 and EP-A-0 568 873, and in DE-A-39 42 860,
DE-A-43 09 074, DE-A-43 09 271, DE-A-43 13 088, DE-A-44 12 489,
DE-A-044 25 834, DE-A-195 25 938, DE-A-196 06 845, DE-A-196 06
846, DE-A-196 15 404, DE-A-196 06 844, DE-A-196 16 569,
DE-A-196 18 270 and DE-A-196 14 349. Particularly useful
detergent additives are sold by BASF AG, Ludwigshafen, under the
trade name Kerocom~ PIBA. These contain polyisobutenylamines
dissolved in aliphatic Clo-C14-hydrocarbons.
For a more exact definition of the individual gasoline fuel
additives mentioned, express reference is made here to the
disclosures of the abovementioned prior art publications.
The. novel gasoline fuel additives or gasoline fuels to which
additives have been added can moreover contain further
conventional components and additives, for example carrier oils,
corrosion inhibitors, demulsifiers and markers.
Examples of useful carrier oils or carrier oil liquids are
mineral carrier oils, synthetic carrier oils and mixtures thereof
which are compatible with the additive or additives used and with
the gasoline fuel. Suitable mineral carrier oils are fractions
obtained in mineral oil processing, such as kerosene or naphtha,
Brightstock or base oils having viscosities of, for example,
class SN 500-2000, as well as aromatic hydrocarbons, paraffinic
-- hydrocarbons and alkoxyalkanols.
Examples of suitable synthetic carrier oils are polyolefins,
(poly)esters, (poly)alkoxylates and in particular polyethers,
aliphatic polyetheramines, alkylphenol-initiated polyethers and
alkylphenol-initiated 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, which are hereby expressly incorporated by
reference. Examples of particularly suitable synthetic carrier
oils are alkanol-initiated polyethers having from about 10 to 35,
for example from about 15 to 30, C3-C6-alkylene oxide units, which
are selected, for example, from propylene oxide, n-butylene oxide
and isobutylene oxide units or mixtures thereof.
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Further conventional additives are corrosion inhibitors, for
example based on ammonium salts of organic carboxylic acids,
which salts tend to form films, or on heterocyclic aromatics in
the case of corrosion protection of nonferrous metals,
antioxidants or stabilizers, for example based on amines, such as
p-phenylenediamine, dicyclohexylamine or derivatives thereof or
on phenols, such as 2,4-di-tert-butylphenol or
3,5-di-tert-butyl-4-hydroxyphenylpropionic acid, demulsifiers,
antistatic agents, metallocenes, such as ferrocene or
methylcyclopentadienylmanganesetricarbonyl, further lubricity
additives, such as specific fatty acids, alkenylsuccinic esters,
bis(hydroxyalkyl)-fatty amines or hydroxyacetarnides and markers.
If required, it is also possible to add amines for reducing the
pH of the fuel.
The novel fuel additive combinations, if required in combination
with one or more of the abovementioned further fuel additives
having the polar groups (a) to (i) and the other components
mentioned, are metered into the fuel and display their action
there. The components or additives can be added to the fuel
individually or as a previously prepared concentrate (additive
packet).
Suitable solvents or diluents (in the preparation of additive
packets) are aliphatic and aromatic hydrocarbons, e.g. solvent
naphtha or kerosene.
The novel fuel additive mixtures are added to the fuel, for
example, in an amount of from ~10 to 150, preferably from 20 to
100, ppm (mg/kg of fuel). The further fuel additives having the
polar groups (a) to (i) are added to the gasoline fuel usually in
an amount of from 10 to 5000 ppm, in particular from 50 to 1000
ppm, and the other components and additives mentioned are, if
desired, added in customary amounts.
The gasoline fuel to which the novel fuel additive mixtures are
added are not subject to any particular restrictions per se. They
may be, for example, a fuel according EN 228. The fuel may be,
for example, a gasoline fuel having an aromatics content of not
more than 42, e.g. from 30 to 42, ~ by volume and a sulfur
content of not more than 150 ppm, e.g. from 5 to 150 ppm.
The gasoline fuel can moreover have an olefin content of not more
than 21, e.g. from 6 to 21, ~ by volume.
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The benzene content may be not more than 1.0, e.g. from 0.5 to
1.0, $ by volume; the oxygen content may be, for example, from
1.0 to 2.7~ by weight.
The content of alcohols and ethers in the gasoline fuel is
usually relatively low. Typical maximum contents are 3$ by volume
for methanol, 5% by volume for ethanol, 10~ by volume for
isopropanol, 7~ by volume for tert-butanol, 10$ by volume for
isobutanol and 15~ by volume for ethers having 5 or more carbon
atoms in the molecule.
The summer vapor pressure of the gasoline fuel is usually not
more than 70, in particular 60, kPa, (in each case at 37~C).
The research octane number (RON) of the gasoline fuel is as a
rule from 90 to 100. A customary range for the corresponding
motor octane number (MON) is from 80 to 90.
The stated specifications are determined by conventional methods
(DIN EN 228).
The non-restricting examples which follow illustrate the
invention.
Examples:
An HFRR (High Frequency Reciprocating Rig; HFR2 from PCS
Instruments, London) and a tribometer as described, for example
in EP-A-0 605 857, were used for testing the lubricity and the
wear, respectively. Measuring conditions adapted to gasoline
- fuels were chosen. The applicability of these test methods is
-- demonstrated in D. Margaroni, Industrial Lubrication and
Tribology, Vol. 50, No. 3, May/June 1998, 108-118 and W.D. Ping,
S. Korcek, H. Spikes, SAE Techn. Paper 962010, 51-59 (1996).
The gasoline fuels used (typical gasoline fuels according to EN
228) were evaporated down to 50% by volume of the original volume
by distillation under gentle conditions before the measurement.
This 50~ residue served as a blank test sample in the testing in
the tribometer and was combined with the novel fuel additive
mixtures or pure additive components in accordance with the.
examples shown below. The resulting frictional wear value is
stated in micrometers. The lower this value, the less the
resulting wear.
CA 02391932 2002-05-15
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Example 1 (according to the invention):
The novel fuel additive mixture was prepared by mixing the
components malefic anhydride (MA)/tridecylamine condensate (50~ by
weight) and castor oil (technical-grade, 50$ by weight). The
components were advantageously mixed at about 50°C. The condensate
was initially taken, and castor oil was then added slowly with
thorough stirring. Thorough stirring or circulation was carried
out until a homogeneous mixture resulted. The condensate was
prepared beforehand by initially taking MA (1.6 parts by weighty
in a solvent (5 parts by weight of heavy solvent naphtha) and
adding tridecylamine (3.4 parts by weight) in such a way that the
reaction temperature did not exceed 90~C.
Example 2 (comparison):
The 50$ residue of a European premium-grade fuel according to EN
228 gave a blank value of 654 micrometers in the HFRR test. The
addition of 50 mg/kg of castor oil according to Example 1 gave a
fretting value of 667 micrometers and hence no improvement in the
lubricity.
Example 3 (comparison):
The 50~ residue of a European premium-grade fuel according to EN
228 gave a blank value of 654 micrometers in the HFRR test. The
addition of 50 mg/kg of MA/tridecylamine condensate, prepared
according to Example 1, gave a fretting value of 669 micrometers
and hence no improvement in the lubricity.
Example 4 (according to the invention):
The 50$ residue of a European premium-grade fuel according to EN
228 was tested by the abovementioned HFRR method and gave a
fretting value of 732 micrometers. The addition of 50 mg/kg of
the additive mixture comprising MA/tridecylamine condensate and
castor oil according to Example 1 led to a substantial
improvement in the fretting value to 688 micrometers and hence
exhibited the synergistic effect in comparison with Examples 2
and 3.
Example 5 (according to the invention):
The 50~ residue of a European premium-grade fuel according to EN
228 gave a blank value of 728 micrometers in the HFRR test. The
addition of 1250 mg/kg of a detergent additive packet (containing
polyisobutenylamine, synthetic carrier oil, corrosion inhibitors
CA 02391932 2002-05-15
~i
14
and kerosene) still led to a value of 710 micrometers. When the
fuel additive according to Example 1 was added, according to the
invention, to his packet, the fretting value was substantially
improved. The further addition of 50 mg/kg of the fuel additive
according to Example 1 to the packet (1250 mg/kg) gave 672
micrometers, while 100 mg/kg gave 655 micrometers.
Example 6 (according to the invention):
The 50~ residue of a European premium-grade fuel according to EN
228 gave a blank value of 872 micrometers in the HFRR test. The
addition of 900 mg/kg of a detergent additive packet (containing
polyisobutene, polyetheramine, corrosion inhibitors and
kerosene), mixed with 50 mg/kg of the fuel additive according to
Example 1, led to 782 micrometers and hence to a significant
improvement in the lubricity.
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CA 02391932 2002-05-15
