Note: Descriptions are shown in the official language in which they were submitted.
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USE OF ADDITIVES FOR IMPROVED ENGINE OPERATION
The present invention concerns the improvement of aspects of internal
combustion engine operation, through in situ improvement of the lubricating
oil by
means of detergent additives.
The use of detergent additives in lubricating oils is well known. Such
additives
may comprise either metal-containing or non metal-containing detergents or
both
1o depending on the application. Such materials may serve a number of
purposes,
including the neutralisation of acidic products which build up the lubricating
oil,
dispersion of solids (such as entrained soot) and maintaining general
cleanliness
of metallic engine surfaces. Conventionally, such additives are incorporated
in the
lubricating oil before the oil is introduced into the engine.
Legislature aimed at reduced emissions has stimulated the technical evolution
of
the internal combustion engine. In particular, the demand for reduced
emissions
has encouraged the development of high pressure fuel injection systems andlor
unit injectors to improve fuel delivery and combustion efficiency. At the same
2o time, the technical demands on lubricating oils have increased with engine
manufacturers requiring lower oil consumption and longer oil drain intervals.
As a
result, the oil's capacity for providing advantageous effects in the
combustion
chamber region of the engine has fallen, with a reduced presence of oil on the
cylinder walls (thereby reducing oil consumption) and the quantity of
lubricating oil
additive supplied to that region being correspondingly lower. At the same
time,
longer oil drain intervals may exhaust the capacity of the detergents in the
bulk oil
to provide their advantageous effects.
Such problems are particularly apparent in the larger internal combustion
engines,
so such as marine diesel engines, where the tower surface area to volume ratio
of
the combustion chamber already limits the relative quality of oil which may
reach
this region, relative to the quantity of combustion products formed.
CONFIRMATION COPY
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As a result of the above trends, problems such as combustion chamber deposits,
for example varnish and lacquer deposits, particularly on the cylinder walls
and
piston crown, generate operational concerns potentially leading to poorer
combustion, shorter engine life and wear. .
It has now been discovered that certain types of detergent additive may be
introduced to the lubricating oil in situ in the combustion chamber region of
the
engine, particularly in the top part of the piston liner area thereby
supplementing
~o the additive present in the lubricating oil and at the same time being
concentrated
in the region of the engine least exposed to the effects of the bulk oil. In
particular, the detergents are introduced in the region of cylinder and piston
deposits and may control the above-mentioned problems in an effective and
efficient manner.
Whilst not wishing to be bound to any particular theory, the applicants
believe that
the nature of these detergents is such that they become entrained in the
lubricating oil layer lining the cylinder walls of the combustion chamber, and
are
thereafter transported either to their site of action in the combustion
chamber area,
or back to the bulk oil (through drainage and replacement of the oil layer),
thereby
also advantageously modifying the properties of the bulk oil. This entrainment
is
considered surprising, particularly in view of the predominantly
hydrocarbonaceous nature of these additives, which would suggest combustion
rather than entrainment as the primary removal mechanism from the combustion
chamber.
Moreover, the benefits due to the concentration increase on the liner may
reduce
the deposits, varnish or carbonaceous matter on the piston grooves, piston
ring
wear and deposits and improve the general cleanliness and performance of the
so engine. In addition, the entrainment of the additive in the oil allows ~
the
enhancement of properties of the lubricant, for example, controlling the
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consequences of lubricant contamination, such as black sludge, piston crown
deposits and fuel pump plunger sticking.
In a first aspect therefore, the invention claims the use of an additive
comprising,
s or obtainable by admixing, A or B or both wherein:
A is a metal-containing detergent, and
B is a non metal-containing detergent,
in an internal combustion engine engine lubricated by means of a separate
lubricating oil system, to enhance the properties of the lubricating oil of
the engine
~o through entrainment therein in the combustion chamber during operation of
the
engine.
The entrainment in the lubricating oil in the combustion chamber may be
achieved
via supply of the additive pre-entrained in the fuel. Such fuels may be
15 hydrocarbon diesel fuels or fuel oil, or of animal or vegetable origin, as
described
below. The additive may be added to the fuel before supply to the vehicle, or
into
the fuel tank of the vehicle at the same time as the fuel.
Alternatively, the additive may be introduced directly into the combustion
chamber
2o separate of the fuel, for example by injection.
The expression 'an engine lubricated by means of a separate lubricating oil
system' refers to those four-stroke and two-stroke engines designed to have
engine lubrication effected by a lubricating oil composition which is supplied
by
2s means other than the fuel. Thus, in such engines, a separate lubricating
oil
reservoir feeds a supply of lubricant to the relevant moving parts of the
engine.
Such a design is in contrast to the design of the smaller gasoline two-stroke
engine, wherein the lubricant is pre-mixed with the fuel and thereafter
introduced
into the engine as part of the fuel composition. The above expression should
so therefore not be considered as including the latter.
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Middle distillate fuels generally boil within the range of about 100°C
to about
500°C, e.g. 150° to about 450°C, for example, those
having a relatively high Final
Boiling Point of above 360°C (ASTM D-86). Such distillates contain a
spread of
hydrocarbons boiling over a temperature range, including n-alkanes which
s precipitate as wax as the fuel cools. They may be characterised by the
temperatures at which various %'s of fuel have vaporised, e.g. 10% to 90%,
being
the interim temperatures at which a certain volume % of initial fuel has
distilled.
The difference between say 90% and 20% distillation temperature may be
significant. They are also characterised by pour, cloud and CFPP points, as
well
~o as their initial boiling point (IBP) and final boiling point (FBP), cetane
number,
viscosity and density. The petroleum fuel oil can comprise atmospheric
distillate
or vacuum distillate, or cracked gas oil or a blend in any proportion of
straight run
and thermally and/or catalytically cracked distillates.
~s The fuel may in particular have one or more of the following
characteristics:
(i) a 95% distillation point (ASTM D86) of greater than 330°C,
preferably
greater than 360°C, more preferably greater than 400°C, and most
preferably greater than 430°C;
20 (ii) a cetane number (measured by ASTM D613) of less than 55, such as less
than 53, preferably less than 49, more preferably less than 45, most
preferably less than 40,
(iii) an aromatic content of greater than 15% wt, preferably greater than 25%
and more preferably greater than 40%; and
2s (iv) a Ramsbottom carbon residue (by ASTM D 524) of greater than 0.01
mass, preferably greater than 0.15% mass, more preferably greater than
0.3% mass, such as 1 % or 5% mass, and most preferably greater than
10% mass.
3o As described earlier, these fuels may in particular contain streams such as
streams produced from fluid catalytic cracking, such materials usually having
a
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density @ 15°C of 850 to 970, such as 900 to 970 kg/m3 and
characterised by low
cetane number values, typically ranging from 10 or lower to around 30 to 35;
from
thermal cracking processes, like visbreaking and coking, such streams
typically
having a density range @ 15°C of 830 to 930 kg/m3 and a cetane value of
20 to
5 50; and from hydrocracking that uses severe conditions, e.g. temperature in
excess of 400°C coupled with pressures of 130 bars or greater, to
produce
streams characterised by cetane number from 45 to 60 and having a density
range @ 15°C from 800 to 860 kg/m3.
~o Typically, marine fuels accord with the standard specification ASTM D-2069
and
may be either distillate or residual fuels as described within that
specification, and
may in particular have sulfur contents of greater than 0.05%, preferably
greater
than 0.1 %, more preferably greater than 0.2% and particularly greater than 1
% or
even 2% by weight, especially in the case of residual fuel. oils, and a
kinematic
~5 viscosity at 40°C in cSt of at least 1.40.
The fuel oil may also be an animal or vegetable oil, or a mineral oil as
described
above in combination with an animal or vegetable oil. Fuels from animal or
vegetable sources are known as biofuels and are obtained from a renewable
2o source. Certain derivatives of vegetable oil, for example rapeseed oil,
e.g. those
obtained by saponification and re-esterification with a monohydric alcohol,
may be
used. It has recently, been reported that mixtures of a rapeseed ester, for
example, rapeseed methyl ester (RME), with petroleum distillate fuels in
ratios of,
for example, 10:90 or 5:95 by volume are likely to be commercially available.
Thus, a biofuel is a vegetable or animal oil or both or a derivative thereof,
particularly an oil comprising fatty acid and/or fatty acid esters.
Vegetable oils are mainly triglycerides of monocarboxylic acids, e.g. acids
3o containing 10-25 carbon atoms and listed below
CH20COR
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CHOCOR
CH20COR
s where R is an aliphatic radical of 10-25 carbon atoms which may be saturated
or
unsaturated.
Generally, such oils contain glycerides of a number of acids, the number and
kind
varying with the source vegetable of the oil.
Examples of oils are rapeseed oil, coriander oil, soyabean oil, cottonseed
oil;
sunflower oil, castor oil, olive oil, peanut oil, maize oil, almond oil, palm
kernel oil,
coconut oil, mustard seed oil, beef tallow and fish oils. Rapeseed oil,
sunflower
oil, soya bean oil and palm oil, is preferred as it is available in large
quantities and
1s can be obtained in a simple way by pressing from rapeseed.
Examples of derivatives thereof are alkyl esters, such as methyl esters, of
fatty
acids of the vegetable or animal oils. Such esters . can be made by
transesterification.
.
As lower alkyl esters of fatty acids, consideration may be given to the
following, for
example as commercial mixtures: the ethyl, propyl, butyl and especially methyl
esters of fatty acids with 12 to 22 carbon atoms, for example of lauric acid,
rosin
acid (e.g. abietic acid and related structures such as dehydroabietic acid)
myristic
2s acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, elaidic
acid; petroselic
acid, ricinoleic acid, elaeostearic acid, linoleic acid, linolenic acid,
eicosanoic acid,
gadoleic acid, docosanoic acid or erucic acid, which have an iodine number
from
50 to 180, especially 90 to 125. Mixtures with particularly advantageous
properties are those which contain mainly, i.e. to at least 50, mass % methyl
esters
so of fatty acids with 16 to 22 carbon atoms and 1, 2 or 3 double bonds. The
preferred lower alkyl esters of fatty acids are the methyl esters of oleic
acid;
linoleic acid, linolenic acid and erucic acid, and mixtures thereof.
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Commercial mixtures of the stated kind are obtained for example by cleavage
and
esterification of natural fats and oils by their transesterification with
lower aliphatic
alcohols. For production of lower alkyl esters of fatty acids it is
advantageous to
s start from fats and oils with high iodine number, such as, for example,
sunflower
oil, rapeseed oil, coriander oil, castor oil, soyabean oil, cottonseed oil,
peanut oil,
fall oil or beef tallow. Lower alkyl esters of fatty acids based on a new
variety of
rapeseed oil, the fatty acid component of which is derived to more than
80 mass % from unsaturated fatty acids with 18 carbon atoms, are preferred.
Preferably the biofuel is present in an amount of up to 50 mass % based on the
mass of the middle distillate fuel oil, more preferably of up to 10 mass %,
especially up to 5 mass %.
The fuel may alternatively be a fuel oil (either distillate or residual fuel)
such as a
heating fuel oil or powerplant fuel.
Metal-containing detergent A
2o The metal-containing detergent may, for example, be an alkaline earth metal
or
alkali metal compound, or a plurality of such compounds.
In both aspects of the invention, whilst overbased compounds may be used, a
neutral alkaline earth metal is particularly suitable, especially one selected
from
2s the group consisting of calcium and magnesium, although barium and
strontium
may also be used. Preferably the alkaline earth metal compound is a calcium
compound
In both aspects of the invention, a neutral alkali metal is also suitable in
the
so present invention and is preferably selected from the group consisting of
lithium,
sodium and potassium. Preferably the alkali metal compound is a sodium or
potassium compound, more preferably a sodium compound.
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Preferably the neutral alkaline earth metal and neutral alkali metal compounds
are
salts of organic acids. As examples of organic acids, there may be mentioned
carboxylic acids and anhydrides thereof, phenols, sulfurised phenols,
salicylic
s acids and anhydrides thereof, alcohols, dihydrocarbyldithiocarbamic acids,
dihydrocarbyldithiophosphoric acids, dihydrocarbylphosphonic acids,
dihydrocarbylthiophosphonic acids and sulfonic acids.
The term 'neutral' as used herein refers to metal compounds, preferably metal
~o salts of organic acids, that are stoichiometric or predominantly neutral in
character, that is most of the metal is associated with an organic anion. For
a
metal compound to be completely neutral, the total number of moles of the
metal.
cation to the total number of moles of organic anion associated with the metal
will
be stoichiometric. For example, for every one mole of calcium cations there
~s should be two moles of sulfonate anions.
The metal salts of the present invention include predominantly neutral salts
where
minor amounts of non-organic anions, for example carbonate and/or hydroxide
anions, may also be present ~ provided their presence does not alter the
2o predominantly neutral character of the metal salt.
Thus, metal salts of the present invention preferably have a metal ratio of
less
than 2, more preferably less than 1.95, especially less than 1.9,
advantageously
less than 1.8, more especially less than 1.6, for example less than 1.5, such
as
2s less than 1.4 or less than 1.35. The metal ratio is preferably at least
about 1Ø
The metal ratio, as used herein, is the ratio of total metal to the metal
associated
with the organic anion. So metal salts having a metal ratio of less than 2
have
greater than 50% of the metal associated with the organic anion.
so The metal ratio can be calculated by
a) measuring the total amount of metal in the neutral metal salt; and
then
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b) determining the amount of metal associated with the organic.
Suitable methods for measuring the total metal content are well known in the
art
and include X-ray fluorescence and atomic absorption spectrometry.
Suitable methods for determining the amount of metal associated with the
organic
acid include potentiometric acid titration of the metal salt to determine the
relative
proportions of the different basic constituents (for example, metal carbonate
and
metal salt of organic acid); hydrolysis of a known amount of metal salt and
then
~o the potentiometric base titration of the organic acid to determine the
equivalent
moles of organic acid; and determination of the non-organic anions, such as
carbonate, by measuring the COZ content.
In the case of a metal sulfonate, ASTM D3712 may be used to determine the
~5 metal associated with the sulfonate.
In the instance where a composition comprises one or more neutral metal salts
and one or more co-additives, then the neutral metal salts) may be separated
from the co-additives, for example, by using dialysis techniques and then the
2o neutral metal salt may be analysed as described above to determine the
metal
ratio. Background information on suitable dialysis techniques is given by
Amos,
R. and Albaugh, E. W. in "Chromatography in Petroleum Analysis" Altgelt, K. H.
and Gouw, T. H., Eds., pages 417 to 421, Marcel Dekker Inc., New York and
Basel, 1979.
Specific examples of organic acids include hydrocarbyl sulfonic acids,
hydrocarbyl
substituted phenols, hydrocarbyl substituted sulfurised phenols, hydrocarbyl
substituted salicylic acids, dihydrocarbyldithiocarbamic acid,
dihydrocarbyldithiophosphoric acid, and aliphatic and aromatic carboxylic
acids.
The neutral metal salts of the present invention may be salts of one chemical
type
or salts of more than one chemical type. Preferably, they are salts of one
type.
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Sulfonic acids used in accordance with this aspect of the invention are
typically
obtained by sulfonation of hydrocarbyl-substituted, especially alkyl-
substituted,
aromatic hydrocarbons, for example, those obtained from the fractionation of
5 petroleum by distillation andlor extraction, or by the alkylation of
aromatic
hydrocarbons. Examples include those obtained by alkylating benzene, toluene,
xylene, naphthalene, biphenyl or their halogen derivatives, for example,
chlorobenzene, chlorotoluene or chloronaphthalene. Alkylation of aromatic
hydrocarbons may be carried out in the presence of a catalyst with alkylating
~o agents having from about 3 to more than 100 carbon atoms, such as, for
example,
haloparaffins, olefins that may be obtained by dehydrogenation of paraffins,
and
polyolefins, for example, polymers of ethylene, propylene, and/or butene. The
alkylaryl sulfonic acids usually contain from about 22 to about 100 or more
carbon
atoms; preferably the alkylaryl sulfonic acids contain at least 26 carbon
atoms,
~s especially at least 28, such as at least 30, carbon atoms. The sulfonic
acids may
be substituted by more than one alkyl group on the aromatic moiety, for
example
they may be dialkylaryl "sulfonic acids. The alkyl group preferably contains
from
about 16 to about 80 carbon atoms, with an average number of carbon atoms in
the range of from 36-40, or an average carbon number of 24, depending on the
2o source from which the alkyl group is obtained. Preferably the sulfonic acid
has a
number average molecular weight, of 350 or greater, more preferably 400 or
greater, especially 500 or greater, such as 600 or greater. Number average
molecular weight may be determined by ASTM D3712.
2s When neutralising these alkylaryl sulfonic acids to provide sulfonates,
hydrocarbon solvents and/or diluent oils may also be included in the reaction
mixture, as well as promoters.
Another type of sulfonic acid which may be used in accordance with the
invention
so comprises alkyl phenol sulfonic acids. Such sulfonic acids can be
sulfurized.
Preferred substituents in alkyl phenol sulfonic acids are substituents
represented
by R in the discussion of phenols below.
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Sulfonic acids suitable for use in accordance with the invention also include
alkyl
sulfonic acids. In such compounds the sulfonic acid suitably contains 22 to
100
carbon atoms, advantageously 25 to 80 carbon atoms, especially 30 to 60 carbon
s atoms.
Preferably the sulfonic acid is hydrocarbyl-substituted aromatic sulfonic
acid, more
preferably alkyl aryl sulfonic acid.
~o Phenols used in accordance with the invention may be non-sulfurized or,
preferably, sulfurized. Further, the term "phenol" as used herein includes
phenols
containing more than one hydroxyl group (for example, alkyl catechols) or
fused
aromatic rings (for example, alkyl naphthols) and phenols which have been
modified by chemical reaction, for example, alkylene-bridged phenols and
15 Mannich base-condensed phenols; and saligenin-type phenols (produced by the
reaction of a phenol and an aldehyde under basic conditions).
Preferred phenols from which neutral calcium and/or magnesium salts in
accordance with the invention may be derived are of the formula
OH
/~
(R)y
where R represents a hydrocarbyl group and y represents 1 to 4. Where y is
greater than 1, the hydrocarbyl groups may be the same or different.
2s The phenols may also be calixarenes, especially of the~formula:
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1
R4 ~ RZ n
R3
Wherein:
Y is a divalent bridging group;
R3 is hydrogen, a hydrocarbyl or a hetero-substituted hydrocarbyl group;
either R' is hydroxyl and RZ and R4 are independently either hydrogen,
hydrocarbyi or hetero-substituted hydrocarbyl, or R~ and R4 are hydroxyl
and R' is either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl;
and
~o n has a value of at least 4.
The phenols are frequently used in sulfurized form. Sulfurized hydrocarbyl
phenols may typically be represented by the formula:
OH OH
~R)v ~R)v
where x, represents an integer from 1 to 4. In some cases, more than two
phenol
molecules may be linked by (S)X bridges, where S represents a sulfur atom.
2o In the above formulae, hydrocarbyl groups represented by R are
advantageously
alkyl groups, which advantageously contain 5 to 100 carbon atoms, preferably 5
to
40 carbon atoms, especially 9 to 12 carbon atoms, the average number of carbon
atoms in all of the R groups being at least about 9 in order to ensure
adequate
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solubility or dispersibility in oil. Preferred alkyl groups are nonyl (e.g.
tripropylene)
groups or dodecyl (e.g. tetrapropylene) groups.
In the following discussion, hydrocarbyl-substituted phenols will for
convenience
be referred to as alkyl phenols.
A sulfurizing agent for use in preparing a sulfurized phenol or phenate may be
any
compound or element which introduces -(S)x- bridging groups between the alkyl
phenol monomer groups, wherein x is generally from 1 to about 4. Thus, the
~.o reaction may be conducted with elemental sulfur or a halide thereof, for
example,
sulfur dichloride or, more preferably, sulfur monochloride. If elemental
sulfur is
used, the sulfurisation reaction may be effected by heating the alkyl phenol
compound at from 50 to 250°C, and preferably at least 100°C. The
use of
elemental sulfur will typically yield a mixture of bridging groups -(S)x-1as
described
~s above. If a sulfur halide is used, the sulfurisation reaction may be
effected by
treating the alkyl phenol at from -10°C to 120°C, preferably at
least 60°C. The
reaction may be conducted in the presence of a suitable diluent. The diluent
advantageously comprises a substantially inert organic diluent, for example
mineral oil or an alkane. In any event, the reaction is conducted for a period
of
2o time sufficient to effect substantial reaction. It is generally preferred
to employ
from 0.1 to 5 moles of the alkyl phenol material per equivalent of sulfurizing
agent.
Where elemental sulfur is used as the sulfurizing agent, it may be desirable
to use
a basic catalyst, for example, sodium hydroxide or an organic amine,
preferably a
2s heterocyclic amine (e.g., morpholine).
Details of sulfurisation processes are well known to those skilled in the art,
for
example US-A-4,228,022 and US-A-4,309,293.
so As indicated above, the term "phenol" as used herein includes phenols which
have been modified by chemical reaction with, for example, an aldehyde, and
Mannich base-condensed phenols.
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Aldehydes with which phenols used in accordance with the invention may be
modified include, for example, formaldehyde, propionaldehyde and
butyraldehyde.
The preferred aldehyde is formaldehyde. Aldehyde-modified phenols suitable for
s use in accordance with the present invention are described in, for example,
US-A-5 259 967.
Mannich base-condensed phenols are prepared by the reaction of a phenol, an
aldehyde and an amine. Examples of suitable Mannich base-condensed phenols
~o are described in GB-A-2 121 432.
In general, the phenols may include substituents other than those mentioned
above. Examples of such substituents are methoxy groups and halogen atoms.
15 Salicylic acids used in accordance with the invention may be non-sulfurized
or
sulfurized, and may be chemically modified and/or contain additional
substituents,
for example, as discussed above for phenols. Processes similar to those for
phenols may also be used for sulfurizing a hydrocarbyl-substituted salicylic
acid,
and are well known to those skilled in the art. Salicylic acids are typically
2o prepared by the carboxylation, by the Kolbe-Schmitt process, of phenoxides,
and
in that case, will generally be obtained (normally in a diluent) in admixture
with
uncarboxylated phenol.
Preferred substituents in oil-soluble salicylic acids from which neutral
calcium
2s and/or magnesium salts in accordance with the invention may be derived are
the
substituents represented by R in the above discussion of phenols. In alkyl-
substituted salicylic acids, the alkyl groups advantageously contain 5 to 100
carbon atoms, preferably 9 to 30 carbon atoms, especially 14 to 20 carbon
atoms.
so Alcohols which may be used are mono- and polyols. The alcohols preferably
have
sufficient number of carbon~atoms to provide adequate oil solubility or
dispersibility
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to a metal salt thereof. Preferred alcohols have at least 4 carbon atoms, an
example of which is tertiary butyl alcohol.
Carboxylic acids which may be used in accordance with the invention include
5 mono- and dicarboxylic acids. Preferred monocarboxylic acids are those
containing 6 to 30 carbon atoms, especially 8 to 24 carbon atoms. (Where this
specification indicates the number of carbon atoms in a carboxylic acid, the
carbon atoms) in the carboxylic groups) is/are included in that number.)
Examples of monocarboxylic acids are iso-octanoic acid, stearic acid, oleic
acid,
~o palmitic acid and behenic acid. Iso-octanoic acid may, if desired, be used
in the
form of the mixture of C8 acid isomers sold by Exxon Chemical under the trade
name "Cekanoic". Other suitable acids are those with tertiary substitution at
the
a-carbon atom and dicarboxylic acids with 2 or more carbon atoms separating
the
carboxylic groups. Further, dicarboxylic acids with more than 35 carbon atoms,
15 for example, 36 to 100 carbon atoms, are also suitable. Unsaturated
carboxylic
acids can be sulfurized.
Specific examples of carboxylic acids include alkyl and alkenyl 'succinic
acids and
anhydrides thereof. Also applicable are aromatic carboxylic acids and
naphthenic
20. acids and hydrocarbyl derivatives thereof. Neo acids such as neodecanoic
acid
and polycarboxylic acids may advantageously be employed.
The organic acids described in GB-A-2,248,068 are herein incorporated by
reference.
In the instance where more than one type of organic acid is present in the
metal
salt, the proportion of any one type to another is not critical provided the
neutral
character of the metal is not altered.
so It will be appreciated by one skilled in the art that a single type of
organic acid may
contain a mixture of acids of the same chemical type. For example, a sulfonic
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16
acid surfactant may contain a mixture of sulfonic acids of varying molecular
weights.
As used in this specification the term "hydrocarbyl" refers to a group having
a
carbon atom directly attached to the rest of the molecule and having a
hydrocarbon or predominantly hydrocarbon character. Examples include
hydrocarbon groups, including aliphatic (e.g. alkyl or alkenyl), alicyclic
(e.g.
cycloalkyl or cycloalkenyl), aromatic, and alicyclic-substituted aromatic, and
aromatic-substituted aliphatic and alicyclic groups. Aliphatic groups are
1o advantageously saturated. These groups may contain non-hydrocarbon
substituents provided their presence does not alter the predominantly
hydrocarbon
character of the group. Examples include keto, halo, hydroxy, nitro, cyano,
alkoxy
and acyl. If the hydrocarbyl group is substituted, a single (mono) substituent
is
preferred.
Examples of substituted hydrocarbyl groups include 2-hydroxyethyl,
3-hydroxypropyl, 4-hydroxybutyl, 2-ketopropyl, ethoxyethyl, and propoxypropyl.
The groups may also or alternatively contain atoms other than carbon in a
chain or
ring otherwise composed of carbon atoms. Suitable hetero atoms include, for
2o example, nitrogen, sulfur, and, preferably, oxygen.
In all aspect of the invention, the Total Base Number (TBN), as measured
according to ASTM D2896, of the neutral alkaline earth metal compounds and
neutral alkali metal compounds is at most 150, such as at most 100, preferably
at
most 80, more preferably at most 70, advantageously at most 60, such as less
than 50.
In both aspects of the invention, a preferred neutral alkaline earth metal
compound is calcium sulfonate or calcium salicylate; especially preferred is a
so calcium salicylate.
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In both aspects of the invention, a preferred neutral alkali metal compound is
selected from the group consisting of sodium sulfonate, sodium salicylate,
potassium sulfonate and potassium salicylate.
In both aspects of the invention, the metal containing detergent may
advantageously be a calcium phenate.
Alternatively, or additionally, the metal-containing detergent may comprise
one or
more transition metal compounds.
In both aspects of the invention, the transition metal is preferably selected
from
the group consisting of iron, manganese, copper, molybdenum, cerium, chromium,
cobalt, nickel, zinc, vanadium and titanium; more preferably, the transition
metal is
iron.
The compound of the transition metal is preferably selected from an organic
acid
salt of a transition metal; ferrocene (Fe[C5H5]2) or a derivative thereof; and
a
manganese carbonyl compound or a derivative thereof.
2o The organic acids suitable for the transition metal are the same as those
described above for the neutral alkaline earth metal and alkali metals.
Specific
examples of preferred transition metal compounds of organic acids are iron
naphthenate, iron oleate, copper naphthenate, copper oleate, copper
dithiocarbamate, copper dithiophosphate, zinc dithiophosphate, zinc
dithiocarbamate, molybdenum dithiocarbamate, molybdenum dithiophosphate,
cobalt naphthenate, cobalt oleate, nickel oleate, nickel naphthenate,
manganese
naphthenate and manganese oleate. Also suitable are alkenyl and alkyl
succinate
salts of iron, copper, cobalt nickel and manganese.
so Other examples of transition metal compounds are ~-bonded ring compounds
where the number of carbon atoms in the ring may be in the range of from 2 to
8,
such as [C5H5], [C6H6], [C8H8]. Examples are dibenzenechromium and
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18
dicyclopentadienyl manganese. Transition metal compounds with one ~-bonded
ring and other ligands such as halogens, CO, RNC and R3P (where R is a
hydrocarbyl group and may be the same or different when there is more than one
R group) are also within the scope of the invention. The ~-bonded ring may be
s heterocyclic such as [C4H4N], [C4H4P] and [C4H4S].
Examples of iron compounds include iron (II) and iron (III) compounds, and
derivatives of ferrocene such as bis(alkyl substituted cyclopentadienyl) iron
compounds, for example bis(methyl cyclopentadienyl) iron. Also compounds
~o such as cyclopentadienyl iron carbonyl compounds, for example,
[C5H6]Fe(CO)~
and [C5H5]Fe(CO)2CI; [C5H5][C4H4N]Fe; and [C5H5][C4H4P]Fe are suitable in the
present invention.
Examples of manganese compounds and derivatives thereof include those
15 described in EP-A-0,476,196 which are incorporated herein by reference.
Specific
examples are cyclopentadienyl manganese carbonyl compounds such as
cyclopentadienyl manganese tricarbonyl and methyl cyclopentadienyl manganese
tricarbonyl.
20 In all aspects of the invention, the fuel-soluble or fuel-dispersible
transition metal
compound is preferably ferrocene or an iron salt of an organic acid, or an
overbased salt thereof, such as iron napthenate or salicylate.
As an alternative to, or in addition to, one or more metal salts of an
inorganic acid,
2s the metal compounds may be in the form of a colloidal dispersion of an
inorganic
salt, e.g. an oxide or carbonate, i.e. may be overbased.
In the instance where two or more metal compounds are present in the additive
composition from any one of the categories of metal compounds, that is (i)
neutral
so alkaline earth metal compounds, (ii) neutral alkali metal compounds and
(iii)
transition metal compounds, the compounds may be of the same or of different
metals within the category.
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Concentration and Proportion
In both aspects of the invention, the total amount of metal by mass, derived
from
s the or each neutral alkaline earth metal compound andlor neutral alkali
metal
compound and/or transition metal compound, in the fuel oil composition is at
most
1000 ppm, but normally at most 250 ppm; preferably the total amount of metal
is
at most 200 ppm, more preferably at most 150 ppm; advantageously at most 100
ppm; especially at most 50 ppm, such as at most 25 ppm, for example in the .
range of from 0.1 to 10 ppm or 0.5 to 5 ppm.
The amount of alkaline earth metal in the fuel oil composition is measured by
atomic absorption; the amount of alkali metal in the fuel oil composition is
measured by atomic absorption; and the amount of transition metal in the fuel
oil
~s composition is measured by atomic absorption.
The non metal-containing detergent
The detergent may be a hydrocarbylamine, such as a polyisobutylene polyamine.
2o The preferred detergent is an ashless dispersant comprising an acylated
nitrogen
compound, preferably having a hydrocarbyl substitutent of at least 10
aliphatic
carbon atoms, made by reacting a carboxylic acid acylating agent with at least
one
amine compound containing at least one -NH-group, said acylating agent being
linked to said amino compound through an imido, amido, amidine, or acyloxy
is ammonium linkage.
A number of acylated, nitrogen-containing compounds having a hydrocarbyl
substituent of at least 10 carbon atoms and made by reacting a carboxylic acid
acylating agent, for example an anhydride or ester, with an amino compound are
so known to those skilled in the art. In such compositions the acylating agent
is
linked to the amino compound through an imido, amido, amidine or acyloxy
ammonium linkage. The hydrocarbyl substituent of 10 carbon atoms may be
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found either in the portion of the molecule derived from the carboxylic acid
acylating agent, or in the portion derived from the amino compound, or in
both.
Preferably, however, it is found in the acylating agent portion. The acylating
agent
can vary from formic acid and its acylating derivatives to acylating agents
having
s high molecular weight hydrocarbyl substituents of up to 5000, 10000 or 20000
carbon atoms. The amino compounds can vary from ammonia itself to amines
having hydrocarbyl substituents of up to about 30 carbon atoms.
A preferred class of acylated amino compounds are those made by reacting an
~o acylating agent having a hydrocarbyl substituent of at least 10 carbon
atoms and
a nitrogen compound characterized by the presence of at least one -NH- group.
Typically, the acylating agent will be a mono- or polycarboxylic acid (or
reactive
equivalent thereof) such as a substituted succinic or propionic acid and the
amino
compound will be a polyamine or mixture of polyamines, most typically, a
mixture
15 of ethylene polyamines. The amine also may be a hydroxyalkyl-substituted
polyamine. The hydrocarbyl substituent in such acylating agents preferably
averages at least about 30 or 50 and up to about 400 carbon atoms.
Illustrative of hydrocarbyl substituent groups containing at least 10 carbon
atoms
2o are n-decyl, n-dodecyl, tetrapropenyl, n-octadecyl, oleyl, chlorooctadecyl,
triicontanyl, etc. Generally, the hydrocarbyl substituents are made from homo-
or
interpolymers (e.g. copolymers, terpolymers) of mono- and di-olefins having 2
to
10 carbon atoms, such as ethylene, propylene, 1-butene, isobutene, butadiene,
isoprene, 1-hexene, 1-octene, etc. Typically, these olefins are 1-monoolefins.
2s This substituent can also be derived from the halogenated (e.g. chlorinated
or
brominated) analogs of such homo-or interpolymers. The substituent can,
however, be made from other sources such as monomeric high molecular weight
alkenes (e.g. 1-tetra-contene) and chlorinated analogs and hydrochlorinated
analogs thereof, aliphatic petroleum fractions, particularly paraffin waxes
and
so cracked and chlorinated analogs and hydrochlorinated analogs thereof, white
oils,
synthetic alkenes such as those produced by the Ziegler-Natta process (e.g.
polyethylene) greases) and other sources known to those skilled in the art.
Any
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21
unsaturation in the substituent may be reduced or eliminated by hydrogenation
according to procedures known in the art.
s The hydrocarbyl substituents are predominantly saturated. The hydrocarbyl
substituents are also predominantly aliphatic in nature, that is, they contain
no
more than one non-aliphatic moiety (cycloalkyl, cycloalkenyl or aromatic)
group of
6 or less carbon atoms for every 10 carbon atoms in the substituent. Usually,
however, the substituents contain no more than one such non-aliphatic group
for
~o every 50 carbon atoms, and in many cases, they contain no such non-
aliphatic
groups at all; that is, the typically substituents are purely aliphatic.
Typically,
these purely aliphatic substituents are alkyl or alkenyl groups.
Specific examples of the predominantly saturated hydrocarbyl substituents
~s containing an average of more than 30 carbon atoms are the following: a
mixture
of polyethylene/ propylene) groups of about 35 to about 70 carbon atoms; a
mixture of poly(propylene/1-hexene) groups of about 80 to about 150 carbon
atoms; a mixture of poly(isobutene) groups having an average of 50 to 75
carbon
atoms; a mixture of poly (1-butene) groups having an average of 50-75 carbon
2o atoms.
A preferred source of the substituents are poly(isobutene)s obtained by
polymerization of a C4 refinery stream having a butene content of 35 to 75
weight
per cent and isobutene content of 30 to 60 weight per cent in the presence of
a
2s Lewis acid catalyst such as aluminium trichloride or boron trifluoride.
These
polybutenes predominantly contain monomer repeating units of the configuration
-C(CH3)2CH2_
so The hydrocarbyl substituent is attached to the succinic acid moiety or
derivative
thereof via conventional means, for example the reaction between malefic
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22
anhydride and an unsaturated substituent precursor such as a polyalkene, as
described for example in EP-B-0 451 380.
One procedure for preparing the substituted succinic acylating agents involves
s first chlorinating the pofyalkene until there is an average of at feast
about one
chloro group for each molecule of polyalkene. Chlorination involves merely
contacting the ~polyalkene with chlorine gas until the desired amount of
chlorine is
incorporated into the chlorinated polyalkene. Chlorination is generally
carried out
at a temperature of about 75°C to about 125°C. If desired, a
diluent can be used
~o in the chlorination procedure. Suitable diluents for this purpose include
poly- and
perchlorinated and/or fluorinated alkanes and benzenes.
The second step in the procedure is to react the chlorinated polyalkene with
the
malefic reactant at.a temperature usually within the range of about
100°C to about
15 200°C. The mole ratio of chlorinated polyalkene to malefic reactant
is usually
about 1:1. However, a stoichiometric excess of malefic reactant can be used,
for
example, a mole ratio of 1:2. If an average of more than about one chloro
group
per molecule of polyalkene is introduced during the chlorination step, then
more
than one mole of malefic reactant can react per molecule of chlorinated
2o polyalkene. It is normally desirable to provide an excess of malefic
reactant; for
example; an excess of about 5% to about 50%, for example 25% by weight.
Unreacted excess malefic reactant may be stripped from the reaction product,
usually under vacuum.
25 Another procedure for preparing substituted succinic acid acylating agents
utilises
a process described in U.S. Pat. No. 3,912,764 and U.K, Pat. No, 1,440,219.
According to that process, the polyalkene and the malefic reactant are first
reacted
by heating them together in a direct alkylation procedure. When the direct
alkylation step is completed, chlorine is introduced into the reaction mixture
to
so promote reaction of the remaining unreacted malefic reactants, According to
the
patents, 0.3 to 2 or more moles of malefic anhydride are used in the reaction
for
each mole of polyalkene. The direct alkylation step is conducted at
temperatures
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23
to 180°C to 250°C. During the chlorine-introducing stage, a
temperature of 160°C
to 225°C is employed.
Other known processes for preparing the substituted succinic acylating agents
include the one-step process described in U.S. Pat. Nos. 3,215,707 and
3,231,587. Basically, this process involves preparing a mixture of the
polyalkene
and the malefic reactant in suitable proportions and introducing chlorine into
the
mixture, usually by passing chlorine gas through the mixture with agitation,
while
maintaining a temperature of at least about 140°C.
Usually, where the polyalkene is sufficiently fluid at 140°C and above,
there is no
need to utilise an additional substantially inert, normally liquid
solvent/diluent in the
one-step process. However, if a solvent/diluent is employed, it is preferably
one
that resists chlorination such as the poly- and per-chlorinated and/or -
fluorinated
alkanes, cycloalkanes, and benzenes.
Chlorine may be introduced continuously or intermittently during the one-step
process. The rate of introduction of the chlorine is not critical although,
for
maximum utilisation of the chlorine, the rate should be about the same as the
rate
of consumption of chlorine in the course of the reaction. When the
introduction
rate of chlorine exceeds the rate of consumption, chlorine is evolved from the
reaction mixture. It is often advantageous to use a closed system, including
superatmospheric pressure, in order to prevent loss of chlorine so as to
maximize
chlorine utilisation.
The minimum temperature at which the reaction in the one-step process takes
place at a reasonable rate is about 140°C. Thus, the minimum
temperature at
which the process is normally carried out is in the neighbourhood of
140°C. The
preferred temperature range is usually between about 160°C and about
220°C.
so Higher temperatures such as 250°C or even higher may be used but
usually with
little advantage. In fact, excessively high temperatures may be
disadvantageous
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24
because of 'the possibility that thermal degradation of either or both of the
reactants may occur at excessively high temperatures.
In the one-step process, the molar ratio of malefic reactant to chlorine is
such that
s there is at least about one mole of chlorine for each mole of malefic
reactant to be
incorporated into the product. Moreover, for practical reasons, a slight
excess,
usually in the neighbourhood of about 5% to about 30% by weight of chlorine,
is
utilised in order to offset any loss of chlorine from the reaction mixture.
Larger
amounts of excess chlorine may be used.
The attachment of the hydrocarbyl substituent to the succinic moiety may
alternatively be achieved via the thermally-driven 'ene' reaction, in the
absence of
chlorine. Use of such a material is the acylating agent (i) leads to products
having
particular advantages; for example, chlorine-free products having excellent
detergency and lubricity properties. In such products, the reactant (i) is
preferably
formed from a polyalkene having at least 30% preferably 50% or more such as
75% of residual unsaturation in the form of terminal, e.g: vinylidene, double
bonds.
The polyamines suitable in this invention are those comprising amino nitrogens
linked by alkylene bridges, which amino nitrogens may be primary, secondary
and/or tertiary in nature. The polyamines may be straight chain, wherein all
the
amino groups will be primary or secondary groups, or may contain cyclic or
branched regions or both, in which case tertiary amino groups may also be
present. The alkylene groups are preferably ethylene or propylene groups, with
2s ethylene being preferred. Such materials may be prepared from the
polymerisation of lower alkylene diamines such as ethylene diamine, a mixture
of
polyamines being obtained, or via the reaction of dichloroethane and ammonia.
The present invention has discovered that the nature of 'the polyamine, and in
so particular the relative proportions of different polyamines within a
polyamine
mixture, may have an important bearing on the performance of the product
defined under the invention.
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(1 ) polyalkylene polyamines of the general formula IV
(R6)2N~U-N(R6)1qN(R6)2 IV
5
wherein each R6 independently represents a hydrogen atom, a
hydrocarbyl group or a hydroxy-substituted hydrocarbyl group containing
up to about 30 carbon atoms, with the proviso that at least one R6
represents a hydrogen atom, q represents an integer in the range from 1 to
10 10 and U represents a C1_1g alkylene group;
(2) heterocyclic-substituted polyamines including hydroxyalkyl-substituted
polyamines
wherein the polyamines are described above and the heterocyclic
15 substituent is for example a piperazine, an imidazoline, a pyrimidine, or a
morpholine; and
(3) aromatic polyamines of the general formula V
2o Ar(N R62)y V
wherein Ar represents an aromatic nucleus of 6 to about 20 carbon atoms,
each R6 is as defined hereinabove and y represents a number from 2 to
about 8.
Specific examples of the polyalkylene polyamines (1 ) are ethylene diamine,
tetra(ethylene)pentamine, tri-(trimethylene)tetramine, and 1,2-propylene
diamine.
Specific examples of hydroxyalkyl-substituted poiyamines include N-(2-
hydroxyethyl) ethylene diamine, N,N1-bis-(2-hydroxyethyl) ethylene diamine,
so N-(3-hydroxybutyl) tetramethylene diamine, etc. Specific examples of the
heterocyclic-substituted polyamines (2) are N-2-aminoethyl piperazine, N-2 and
N-3 amino propyl morpholine, N-3-(dimethyl amino) propyl piperazine, 2-heptyl-
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26
3-(2-aminopropyl) imidazoline, 1,4-bis (2-aminoethyl) piperazine, 1-(2-hydroxy
ethyl) piperazine, and 2-heptadecyl-1-(2-hydroxyethyl)-imidazoline, etc.
Specific
examples of the aromatic polyamines (3) are the various isomeric phenylene
diamines; the various isomeric naphthalene diamines, etc.
Many patents have described useful acylated nitrogen compounds including US
patents 3 172 892; 3 219 666; 3 272 746; 3 310 492; 3 341 542; 3 444 170;
3 455 831; 3 455 832; 3 576 743; 3 630 904; 3 632 511; 3 804 763 and
4 234 435, and including European patent applications EP 0 336 664 and
~o EP 0 263 703. A typical and preferred compound of this class is that made
by
reacting a poly(isobutylene)-substituted succinic anhydride acylating agent
(e.g.
anhydride, acid, ester, etc.) wherein the poly(isobutene) substituent has,
between
about 50 to about 400 carbon atoms with a mixture of ethylene polyamines
having
3 to about 7 amino nitrogen atoms per ethylene polyamine and about 1 to about
6
~s ethylene groups. In view of the extensive disclosure of this type of
acylated amino
compound, further discussion of their nature and method of preparation is not
needed here. The above-noted US patents are utilized for their disclosure of
acylated amino compounds and their method of preparation.
2o Preferred materials also include those made from amine mixtures comprising
polyamines having seven and eight, and optionally nine, nitrogen atoms per
molecule (so-called 'heavy' polyamines).
More preferably, the polyamine mixture comprises at least 45% and preferably
2s 50% by weight of polyamines having seven nitrogen atoms per molecule, based
on the total weight of polyamines.
The polyamine component (ii) may be defined by the average number of nitrogen
atoms per molecule of the component (ii), which may preferably be in the range
of
30 6.5 to 8.5, more preferably 6.8 to 8, especially 6.8 to 7.5 nitrogens per
molecule.
The number of nitrogens appears to influence the ability of the product to
provide
deposit control.
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27
The reaction of polyamine with the acylating agent is carried out in the
appropriate ratio, as above defined. Preferably, the molar ratio of acylating
agent
to polyamine is in the range of from 2.5:1, to 1.05:1 preferably 1.7:1 or
1.05:1,
s such as 1.35:1 to 1.05:1, more preferably 1.3:1 to 1.15:1, and most
preferably
1.25:1 to 1.15:1. For this purpose, the molar quantity of acylating agent
refers to
the molar quantity of polyisobutylene succinic anhydride (pibsa) formed during
the
reaction procedure as previously described, and does not typically refer to
the
total molar quantity of polyisobutylene (pib) found in the pibsa reactant (i)
which
may be higher if unreacted pib remains from the pibsa formation reaction. The
molar quantity of pibsa is typically determined by titration, e.g. via
saponification of
the reacted malefic anhydride moieties. The specific mixture of individual
reaction
products obtained by operating within such ratios has been found to be
particularly useful for fuel oil applications, especially middle distillate
fuel oil
~s applications.
The reaction is typically carried out at conventional temperatures in the
range of
about 80°C to about 200°C, more preferably about 140°C to
about 180°C. These
reactions may be conducted in the presence or absence of an ancillary diluent
or
20 liquid reaction medium, such as a mineral oil or aromatic solvent. If the
reaction is
conducted in the absence of an ancillary solvent of this type, such is usually
added to the reaction product on completion of the reaction. In this way the
final
product is in the form of a convenient solution and thus is compatible with an
oil. ,
The same solvent could be used in the manufacturing of the metal detergent.
2s Suitable solvent oils are oils used as a lubricating oil basestock, and
these
generally include lubricating oils having a viscosity (ASTM D 445) of 2 to 40,
preferably 3 to 12 mm2/sec at 100°C, with the primarily paraffinic
mineral oils, such
as those in the range of Solvent 90 to Solvent 150 Neutral, being preferred.
so More preferred are aromatic solvents which give rise to particularly low
viscosity
products and result in products having surprisingly advantageous compatibility
when blended with other components in the additive. Advantageous solvents
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28
include xylenes, trimethylbenzene, ethyl toluene, diethylbenzene, cymenes,
amylbenzene, diisopropyl benzene, or mixtures thereof, optionally with
isoparaffins. Products obtained via reaction in such solvents can be blended
to
form particularly homogeneous additives containing other additive components.
Another type of acylated nitrogen compound belonging to this class is that
made
by reacting the afore-described alkylene amines with the afore-described
substituted succinic acids or anhydrides and aliphatic mono-carboxylic acids
having from 2 to about 22 carbon atoms. In these types of acylated nitrogen
~o compounds, the mole ratio of succinic acid to mono-carboxylic acid ranges
from
about 1:0.1 to about 0.1:1, such as 1:1. Typical of the mono-carboxylic acid
are
formic acid, acetic acid, dodecanoic .acid, butanoic acid, oleic acid, stearic
acid,
the commercial mixture of stearic acid isomers known as isosteric acid, tolyl
acid,
etc. Such materials are more fully described in US patents 3 216 936 and
~5 3 250 715.
Still another type of acylated nitrogen compound useful as compatibilising
agent is
the product of the reaction of a fatty monocarboxylic acid of about 12-30
carbon
atoms and the afore-described alkylene amines, typically, ethylene, propylene
or
2o trimethylene polyamines containing 2 to 8 amino groups and mixtures
thereof.
The fatty mono-carboxylic acids are generally mixtures of straight and
branched
chain fatty carboxylic acids containing 12-30 carbon atoms. A widely used type
of
acylating nitrogen compound is made by reacting the afore-described alkylene
polyamines with a mixture of fatty acids having from 5 to about.30 mole per
cent
25 straight' chain acid and about 70 to about 95 mole per cent branched chain
fatty
acids. Among the commercially available mixtures are those known widely in the
trade as isostearic acid. These mixtures are produced as by-product from the
dimerization of unsaturated fatty acids as described in US patents 2 812 342
and
3 260 671.
The branched chain fatty acids can also include those in which the branch is
not
alkyl in nature, such as found in phenyl and cyclohexyl stearic acid and the
chloro-
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29
stearic acids. Branched chain fatty carboxylic acid/alkylene polyamine
products
have been described extensively in the art. See for example, US patents
3 110 673; 3 251 853; 3 326 801; 3 337 459; 3 405 064; 3 429 674; 3 468 639;
3 857 791. These patents are utilized for their disclosure of fatty acid-
polyamine
s condensates for their use in oleaginous formulations.
The preferred acylated nitrogen compounds are those made by reacting a poly
(isobutene) substituted succinic anhydride acylating agent with mixtures of
ethylene polyamines as hereinbefore described.
Additive Composition
An additive composition or concentrate comprising the detergents of the
present
invention may be in admixture with a carrier liquid (e.g. as a solution or a
dispersion). Such concentrates are convenient as a means for incorporating the
metal compounds into bulk fuel oil such as distillate fuel oil, which
incorporation
may be done by methods known in the art. The concentrates may also contain
other fuel additives as required and preferably contain from 1 to 75 mass %,
more
preferably 2 to 60 mass %, most preferably 5 to 50 mass % of the additives,
2o based on active ingredient, preferably in solution in the carrier liquid.
Examples of
carrier liquids are organic solvents including hydrocarbon solvents, for
example
petroleum fractions such as naphtha, kerosene, lubricating oil, diesel fuel
oil and
heating oil; aromatic hydrocarbons such as aromatic fractions, e.g. those sold
under the 'SOLVESSO' tradename; alcohols such as hexanol and higher alkanols;
2s esters such as rapeseed methyl ester and paraffinic hydrocarbons such as
hexane and pentane and isoparaffins. The carrier liquid must, of course, be
selected having regard to its compatibility with the additives and with the
fuel oil.
The detergents of the present invention may be incorporated into the bulk fuel
oil
so by other methods such as those known in the art. If co-additives are
required,
they may be incorporated into the bulk fuel oil at the same time as the metal
compounds of the present invention or at a different time.
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Accordingly, the present invention also provides a process for preparing a
fuel oil
composition either wherein an additive comprising the detergents is
incorporated,
preferably by blending or mixing, into a fuel oil, or wherein the detergents
of the
s present invention are incorporated , preferably by blending or mixing, into
the fuel
oil contemporaneously or sequentially.
Co-Additives
~o The detergents of the present invention may be used in combination with one
or
more co-additives such as known in the art, for example the following: cold
flow
improvers, wax anti-settling agents, dispersants, antioxidants, corrosion
inhibitors,
dehazers, demulsifiers, metal deactivators, antifoaming agents, cetane
improvers,
cosolvents, package compatibilisers, other lubricity additives, biocides and
~s antistatic additives.
It should be appreciated that interaction may take place between any two or
more
of the compounds of the present invention after they have been incorporated
into
the fuel oil or additive composition, for example, between two different
neutral
2o alkaline earth metal compounds or between a neutral alkaline earth metal
compound and a neutral alkali metal or between a neutral alkaline earth metal
compound and a transition metal compound or between a neutral alkaline earth
metal compound, a neutral alkali metal compound and a transition metal
compound. The interaction may take place in either the process of mixing or
any
2s subsequent condition to which the composition is exposed, including the use
of
the composition in its working environment. Interactions may also take place
when further auxiliary additives are added to the compositions of the
invention or
with components of fuel oil. Such interaction may include interaction which
alters
the chemical constitution of the metal compounds. Thus for example the
so compositions of the invention include compositions in which interaction
between
any of the metal compounds has occurred, as well as compositions in~ which no
interaction has occurred between the components mixed in the fuel oil.
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31
The Engines
The engines suitable in the use include compression-ignition (diesel) engines
such
as those found in vehicles.
In particular, suitable engines are those larger diesel engines of four-stroke
or two-
stroke design having one or more of the following operating parameters:
(i) a maximum engine speed of no more than 1000 rpm (revolutions per
9o minute) for four stroke engines, and of no more than 2,500 rpm for two
stroke engines;
(ii) a power output of greater than 200 bhp (brake horse-power);
(iii) a cylinder bore dimension of greater than 150 mm for four stroke
engines,
(such as greater than 200mm) or of greater than 100 mm for two stroke
~s engines; and
(iv) a piston stroke of greater than 150 mm for four stroke engines (such as
greater than 250mm) or of greater than 120 mm for two-stroke engines.
The engines primarily suited to the use of the invention are those four stroke
2o marine diesel engines defined by the above operating parameters and found
primarily in fishing vessels and other medium-sized craft. This combination of
parameters appear to correlate both with the type of application for these
engines,
and also with the problems observed during use. Alternatively, two-stroke
engines
lubricated by means of a separate lubricating oil system and having the above
2s operating parameters may be used. Such engines may also be found in marine
or
stationary applications and railway applications.
The four stroke engines suitable in the invention preferably possess the
operating
parameters (i) and (ii) as defined above, more preferably the parameters (i),
(ii)
so and (iii), and most preferably the parameters (i), (ii), (iii) and (iv).
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The two stroke engines suitable in the invention preferably possess the
operating
parameters (i) and (ii) as defined above, more preferably the parameters (i),
(ii)
and (iii) and most preferably the parameters (i), (ii), (iii) and (iv).
s Of the four-stroke engines, particularly suitable engines are those having a
power
output of above 250 bhp, and especially those having an output over 600 bhp,
such as over 1000 bhp. Especially suitable are those having cylinder bore
dimensions of greater than 180 mm and piston strokes of greater than 180 mm
and more preferably bores of greater than 240 mm and strokes of greater than
~0 290 mm, such as bores of greater than 320 and strokes of greater than 320
mm,
including the largest engines having bores of greater than 430 mm and strokes
of
greater than 600 mm.
Of the two-stroke engines, particularly suitable engines are those having a
power
~s output above 200 bhp and more preferably above 1000 bhp. Especially
suitable
are those engines having bores of greater than 240 mm, such as greater than
400
or 500 mm, and strokes of greater than 400 mm or 500 mm, such as greater than
1000 mm. Such large two-stroke engines include the "crosshead" type engines
used in marine applications.
The invention will now be illustrated with the following examples:
Example 1
2s Lubricating oil viscosity tests were performed using two 15W40 multigrade
oils.
Oil 1 was a standard CEC crankcase oil used for CEC fuel tests and passing the
Renault 5, Mercedes 102E and M-111, Peugeot XUD9 and VW Waterboxer test
requirements. Oil 2 satisfied the A.PI CE and CF4 requirements.
so Additives A and B were tested in each oil at the 1 % and 10% levels and the
kinematic viscosities (at 40°C) of the resulting compositions measured.
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Additive A was a neutral calcium sulfonate wherein the sulfonate was
substituted
with a mixture of alkyl chains containing 36 carbons and 12 carbons. Additive
B
was a polyisobutylene succinimide having a polyisobutylene chain of Mn
approximately 950.
Table 1 - Viscosity Results
Lubricity Oil Viscosity
(KV @ 40C)
Oil 1 Oil 2
Oil 101.3 98.62
Oil + Additive A (1 105.9 100.2
%) 118.5 112.6
Oil + Additive A (10%)
Oil + Additive B (1 107.6 101.8
%) 121.6 117.9
Oil + Additive B (10%)
1o Example 2 - Engine testing
Additives A and B, along with further additive C, were tested in a ICH Deutz
marine
engine and the resulting engine deposits and wear on the pistons, piston rings
and cylinder liners measured.
The engine had the following characteristics:
Type: Single cylinder
Bore: 240mm
2o Stroke: 280mm
Speed: 900 rpm
Power: 225 kW
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The effects of the combination of additives A and B, were compared to the
effects
observed in the absence of additives, for each of two reference lubricating
oils
(high and medium quality). Each test run involved 192 hours of engine
operation
after which the engine parameters shown in the table were measured. In
addition
the combination of A and C was run on high quality oil, but only for a period
of 160
hours due to mechanical failure of the test bed.
Table 2 - Engine Test Results
Parameter High Medium Quality
Quality
Lubricating
Oil
Lubricating
Oil
A+B'A+C2 Ref Ref Ref A+B Ref
1 2 3 ~
Piston Land & grooves,
Total weighed demerits360 33 115 134 197 177 161
Cylinder lacquers,
merits4
- Full ring travel 9.459.35 9.35 8.93 8.78 8.25 8.06
- Top 25% 8.768.39 8.46 7.50 7.67 6.44 6.05
Bore polish, %5 0 - 0 0 0 0 0
Top Land (Crown Land)
Polished Carbon, 46 1 42 35 41 31 47
%
Top Groove Fill, 0 0 0 0 1 2 2
%
2~a Groove Fill, 0 2 2 2 4 8 26
%
Footnotes to table:
'Additive combination 'A + B' comprised 46.6% by weight of A, 25.0% by weight
of
B, 25.4% by weight of aromatic solvent and 3.0% by weight of a
polyoxyalfcylene
based demulsifier (not believed to affect the engine parameters measured), to
a
total treat rate of 500 ppm (weight of additive to weight of fuel).
2Additive combination A + C comprised a corresponding formulation, but wherein
s5 additive C was a calcium phenate having TBN (total base number) of 147 and
containing 70% of the calcium in the form of an inorganic salt combination
with
phenate anion, the remainder being inorganic calcium associated with the
modicum of overbasing present.
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3 Demerits refers to the degree of deposition, i.e. the greater the demerits
the
poorer (dirtier) the condition of the piston
4conversely, merits refers to the degree of cleanliness of the cylinder on a
scale of
0 (dirty) to 10 (clean). Thus, greater merits indicates less laquer and a
cleaner
s surface
5 bore polish not recorded for 'A + C'.
The advantageous results of the present 'invention are clearly seen from Table
2.
Combinations A+B and A+C showed substantially lower piston demerits (i.e.
lower
~o piston deposits). A+B was particularly effective also against cylinder
laquer, whilst
A+C showed particularly good control of polish on the piston top land.
