U.S. patent application number 10/258415 was filed with the patent office on 2003-09-04 for use of additives for improved engine operation.
Invention is credited to Caprotti, Rinaldo, Van Leest, Peter.
Application Number | 20030163948 10/258415 |
Document ID | / |
Family ID | 9891657 |
Filed Date | 2003-09-04 |
United States Patent
Application |
20030163948 |
Kind Code |
A1 |
Van Leest, Peter ; et
al. |
September 4, 2003 |
Use of additives for improved engine operation
Abstract
Engine operation is improved by means of detergent additives. An
additive comprising, or obtainable by admixing, A or B or both
wherein: A is a metal-containing detergent, and B is a non
metal-containing detergent, is used in an internal combustion
engine lubricated by means of a separate lubricating oil system, to
enhance the properties of the lubricating oil of the engine through
entrainment therein the combustion chamber during operation of the
engine.
Inventors: |
Van Leest, Peter;
(Rotterdam, GB) ; Caprotti, Rinaldo; (Oxfordshire,
GB) |
Correspondence
Address: |
Infeneum USA
Law Department
1900 East Linden Avenue
P O Box 710
Linden
NJ
07036-0710
US
|
Family ID: |
9891657 |
Appl. No.: |
10/258415 |
Filed: |
April 17, 2003 |
PCT Filed: |
May 14, 2001 |
PCT NO: |
PCT/EP01/05487 |
Current U.S.
Class: |
44/347 |
Current CPC
Class: |
C10L 1/2437 20130101;
C10L 1/1828 20130101; C10M 163/00 20130101; C10M 141/08 20130101;
C10L 1/2383 20130101; C10M 2219/044 20130101; C10N 2010/04
20130101; C10M 2219/046 20130101; C10N 2030/04 20130101; C10L 1/14
20130101; C10N 2030/06 20130101; C10M 2215/28 20130101; C10N
2040/252 20200501; C10N 2040/25 20130101 |
Class at
Publication: |
44/347 |
International
Class: |
C10L 001/22; C10L
001/24 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 2000 |
GB |
0011733.3 |
Claims
1. The use of an additive comprising, 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
lubricated by means of a separate lubricating oil system, to
enhance the properties of the lubricating oil of the engine through
entrainment therein in the combustion chamber during operation of
the engine.
2. The use of claim 1 wherein the engine is a four stroke
engine.
3. The use of claim 1 or claim 2 wherein the additive is supplied
to the combustion chamber entrained in the fuel.
4. The use of any preceding claim wherein the additive is
preferentially absorbed into the lubricating oil lining the
combustion chamber.
5. The use of any preceding claim wherein the additive enhances the
viscosity characteristics of the lubricating oil upon entrainment
therein, reducing the oil consumption of the engine.
6. The use of any of claims 1 to 4 wherein the additive enhances
the deposit control characteristics of the lubricating oil upon
entrainment therein.
7. The use of the preceding claims wherein the engine is a diesel
engine.
8. The use of any preceding claim wherein component A is a
calcium-containing detergent.
9. The use of any preceding claim wherein component B is a
polyisobutylene succinimide.
10. The use of claim 9 when dependent upon claim 8.
Description
[0001] 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.
[0002] 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 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.
[0003] 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 and/or unit
injectors to improve fuel delivery and combustion efficiency. At
the same 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.
[0004] Such problems are particularly apparent in the larger
internal combustion engines, such as marine diesel engines, where
the lower 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.
[0005] 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.
[0006] 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 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.
[0007] 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.
[0008] 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 engine. In addition,
the entrainment of the additive in the oil allows the enhancement
of properties of the lubricant, for example, controlling the
consequences of lubricant contamination, such as black sludge,
piston crown deposits and fuel pump plunger sticking.
[0009] In a first aspect therefore, the invention claims the use of
an additive comprising, or obtainable by admixing, A or B or both
wherein:
[0010] A is a metal-containing detergent, and
[0011] B is a non metal-containing detergent,
[0012] 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 through entrainment therein in
the combustion chamber during operation of the engine.
[0013] 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 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.
[0014] Alternatively, the additive may be introduced directly into
the combustion chamber separate of the fuel, for example by
injection.
[0015] 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 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
therefore not be considered as including the latter.
[0016] Middle distillate fuels generally boil within the range of
about 100.degree. C. to about 500.degree. C., e.g. 150.degree. to
about 450.degree. C., for example, those having a relatively high
Final Boiling Point of above 360.degree. C. (ASTM D-86). Such
distillates contain a spread of hydrocarbons boiling over a
temperature range, including n-alkanes which 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 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.
[0017] The fuel may in particular have one or more of the following
characteristics:
[0018] (i) a 95% distillation point (ASTM D86) of greater than
330.degree. C., preferably greater than 360.degree. C., more
preferably greater than 400.degree. C., and most preferably greater
than 430.degree. C.;
[0019] (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,
[0020] (iii) an aromatic content of greater than 15% wt, preferably
greater than 25% and more preferably greater than 40%; and
[0021] (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.
[0022] As described earlier, these fuels may in particular contain
streams such as streams produced from fluid catalytic cracking,
such materials usually having a density @ 15.degree. C. of 850 to
970, such as 900 to 970 kg/m.sup.3 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.degree. C. of
830 to 930 kg/m.sup.3 and a cetane value of 20 to 50; and from
hydrocracking that uses severe conditions, e.g. temperature in
excess of 400.degree. 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.degree. C. from 800 to 860
kg/m.sup.3.
[0023] 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 viscosity at 40.degree. C. in cSt of at
least 1.40.
[0024] 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 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.
[0025] 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.
[0026] Vegetable oils are mainly triglycerides of monocarboxylic
acids, e.g. acids containing 10-25 carbon atoms and listed below:
1
[0027] where R is an aliphatic radical of 10-25 carbon atoms which
may be saturated or unsaturated.
[0028] Generally, such oils contain glycerides of a number of
acids, the number and kind varying with the source vegetable of the
oil.
[0029] 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 can be obtained in a simple way by pressing
from rapeseed.
[0030] 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.
[0031] 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 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 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.
[0032] 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 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.
[0033] 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 %.
[0034] The fuel may alternatively be a fuel oil (either distillate
or residual fuel) such as a heating fuel oil or powerplant
fuel.
[0035] Metal-containing detergent A
[0036] The metal-containing detergent may, for example, be an
alkaline earth metal or alkali metal compound, or a plurality of
such compounds.
[0037] In both aspects of the invention, whilst overbased compounds
may be used, a neutral alkaline earth metal is particularly
suitable, especially one selected from 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.
[0038] In both aspects of the invention, a neutral alkali metal is
also suitable in the 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.
[0039] 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 acids
and anhydrides thereof, alcohols, dihydrocarbyldithiocarbamic
acids, dihydrocarbyidithiophosphoric acids, dihydrocarbyiphosphonic
acids, dihydrocarbylthiophosphonic acids and sulfonic acids.
[0040] The term `neutral` as used herein refers to metal compounds,
preferably metal 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 should be two moles of sulfonate anions.
[0041] 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 predominantly
neutral character of the metal salt.
[0042] 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 less
than 1.4 or less than 1.35. The metal ratio is preferably at least
about 1.0. 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.
[0043] The metal ratio can be calculated by
[0044] a) measuring the total amount of metal in the neutral metal
salt; and then
[0045] b) determining the amount of metal associated with the
organic.
[0046] Suitable methods for measuring the total metal content are
well known in the art and include X-ray fluorescence and atomic
absorption spectrometry.
[0047] 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 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 CO.sub.2 content.
[0048] In the case of a metal sulfonate, ASTM D3712 may be used to
determine the metal associated with the sulfonate.
[0049] In the instance where a composition comprises one or more
neutral metal salts and one or more co-additives, then the neutral
metal salt(s) may be separated from the co-additives, for example,
by using dialysis techniques and then the 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.
[0050] Specific examples of organic acids include hydrocarbyl
sulfonic acids, hydrocarbyl substituted phenols, hydrocarbyl
substituted sulfurised phenols, hydrocarbyl substituted salicylic
acids, dihydrocarbyldithiocarbamic acid,
dihydrocarbyidithiophosphoric acid, and aliphatic and aromatic
carboxylic acids.
[0051] 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.
[0052] 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
petroleum by distillation and/or 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 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, 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 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.
[0053] 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.
[0054] Another type of sulfonic acid which may be used in
accordance with the invention 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.
[0055] 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
atoms.
[0056] Preferably the sulfonic acid is hydrocarbyl-substituted
aromatic sulfonic acid, more preferably alkyl aryl sulfonic
acid.
[0057] 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 Mannich base-condensed phenols; and saligenin-type
phenols (produced by the reaction of a phenol and an aldehyde under
basic conditions).
[0058] Preferred phenols from which neutral calcium and/or
magnesium salts in accordance with the invention may be derived are
of the formula 2
[0059] 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.
[0060] The phenols may also be calixarenes, especially of the
formula: 3
[0061] Wherein:
[0062] Y is a divalent bridging group;
[0063] R.sup.3 is hydrogen, a hydrocarbyl or a hetero-substituted
hydrocarbyl group;
[0064] either R.sup.1 is hydroxyl and R.sup.2 and R.sup.4 are
independently either hydrogen, hydrocarbyl or hetero-substituted
hydrocarbyl, or R.sup.2 and R.sup.4 are hydroxyl and R.sup.1 is
either hydrogen, hydrocarbyl or hetero-substituted hydrocarbyl;
and
[0065] n has a value of at least 4.
[0066] The phenols are frequently used in sulfurized form.
Sulfurized hydrocarbyl phenols may typically be represented by the
formula: 4
[0067] where x, represents an integer from 1 to 4. In some cases,
more than two phenol molecules may be linked by (S).sub.x bridges,
where S represents a sulfur atom.
[0068] 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
solubility or dispersibility in oil. Preferred alkyl groups are
nonyl (e.g. tripropylene) groups or dodecyl (e.g. tetrapropylene)
groups.
[0069] In the following discussion, hydrocarbyl-substituted phenols
will for convenience be referred to as alkyl phenols.
[0070] A sulfurizing agent for use in preparing a sulfurized phenol
or phenate may be any compound or element which introduces
--(S).sub.x-- bridging groups between the alkyl phenol monomer
groups, wherein x is generally from 1 to about 4. Thus, the
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.degree. C., and preferably at least 100.degree. C.
The use of elemental sulfur will typically yield a mixture of
bridging groups --(S).sub.x-- as described above. If a sulfur
halide is used, the sulfurisation reaction may be effected by
treating the alkyl phenol at from -10.degree. C. to 120.degree. C.,
preferably at least 60.degree. 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 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.
[0071] 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 heterocyclic amine
(e.g., morpholine).
[0072] Details of sulfurisation processes are well known to those
skilled in the art, for example U.S. Pat. No. 4,228,022 and U.S.
Pat. No. 4,309,293.
[0073] 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.
[0074] 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 use in
accordance with the present invention are described in, for
example, U.S. Pat. No. 5,259,967.
[0075] Mannich base-condensed phenols are prepared by the reaction
of a phenol, an aldehyde and an amine. Examples of suitable Mannich
base-condensed phenols are described in GB-A-2 121 432.
[0076] In general, the phenols may include substituents other than
those mentioned above. Examples of such substituents are methoxy
groups and halogen atoms.
[0077] 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 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.
[0078] Preferred substituents in oil-soluble salicylic acids from
which neutral calcium 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. 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 to a metal salt
thereof. Preferred alcohols have at least 4 carbon atoms, an
example of which is tertiary butyl alcohol.
[0079] Carboxylic acids which may be used in accordance with the
invention include 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 atom(s) in the carboxylic group(s) is/are included in that
number.) Examples of monocarboxylic acids are iso-octanoic acid,
stearic acid, oleic acid, 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 .alpha.-carbon atom and dicarboxylic acids with
2 or more carbon atoms separating the carboxylic groups. Further,
dicarboxylic acids with more than 35 carbon atoms, for example, 36
to 100 carbon atoms, are also suitable. Unsaturated carboxylic
acids can be sulfurized.
[0080] Specific examples of carboxylic acids include alkyl and
alkenyl succinic acids and anhydrides thereof. Also applicable are
aromatic carboxylic acids and naphthenic acids and hydrocarbyl
derivatives thereof. Neo acids such as neodecanoic acid and
polycarboxylic acids may advantageously be employed.
[0081] The organic acids described in GB-A-2,248,068 are herein
incorporated by reference.
[0082] 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.
[0083] 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 acid surfactant may
contain a mixture of sulfonic acids of varying molecular
weights.
[0084] 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 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.
[0085] 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 example, nitrogen, sulfur, and, preferably, oxygen.
[0086] 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.
[0087] In both aspects of the invention, a preferred neutral
alkaline earth metal compound is calcium sulfonate or calcium
salicylate; especially preferred is a calcium salicylate.
[0088] 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.
[0089] In both aspects of the invention, the metal containing
detergent may advantageously be a calcium phenate.
[0090] Alternatively, or additionally, the metal-containing
detergent may comprise one or more transition metal compounds.
[0091] 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.
[0092] The compound of the transition metal is preferably selected
from an organic acid salt of a transition metal; ferrocene
(Fe[C.sub.5H.sub.5].sub.2) or a derivative thereof; and a manganese
carbonyl compound or a derivative thereof.
[0093] 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.
[0094] Other examples of transition metal compounds are .pi.-bonded
ring compounds where the number of carbon atoms in the ring may be
in the range of from 2 to 8, such as [C.sub.5H.sub.5],
[C.sub.6H.sub.6], [C.sub.8H.sub.8]. Examples are dibenzenechromium
and dicyclopentadienyl manganese. Transition metal compounds with
one .pi.-bonded ring and other ligands such as halogens, CO, RNC
and R.sub.3P (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 .pi.-bonded ring may be heterocyclic
such as [C.sub.4H.sub.4N], [C.sub.4H.sub.4P] and
[C.sub.4H.sub.4S].
[0095] 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 such as
cyclopentadienyl iron carbonyl compounds, for example,
[C.sub.5H.sub.6]Fe(CO).sub.3 and [C.sub.5H.sub.5]Fe(CO).sub.2Cl;
[C.sub.5H.sub.5][C.sub.4H.sub.4N]Fe; and
[C.sub.5H.sub.5][C.sub.4H.sub.4P]Fe are suitable in the present
invention.
[0096] Examples of manganese compounds and derivatives thereof
include those 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.
[0097] 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.
[0098] As an alternative to, or in addition to, one or more metal
salts of an inorganic acid, 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.
[0099] 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 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.
[0100] Concentration and Proportion
[0101] In both aspects of the invention, the total amount of metal
by mass, derived from the or each neutral alkaline earth metal
compound and/or 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.
[0102] 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 composition is
measured by atomic absorption.
[0103] The non metal-containing detergent
[0104] The detergent may be a hydrocarbylamine, such as a
polyisobutylene polyamine. 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 ammonium linkage.
[0105] 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 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 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 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.
[0106] A preferred class of acylated amino compounds are those made
by reacting an 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 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.
[0107] Illustrative of hydrocarbyl substituent groups containing at
least 10 carbon atoms 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. 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 cracked and chlorinated analogs and
hydrochlorinated analogs thereof, white oils, synthetic alkenes
such as those produced by the Ziegler-Natta process (e.g.
poly(ethylene) greases) and other sources known to those skilled in
the art. Any unsaturation in the substituent may be reduced or
eliminated by hydrogenation according to procedures known in the
art.
[0108] 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 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.
[0109] Specific examples of the predominantly saturated hydrocarbyl
substituents containing an average of more than 30 carbon atoms are
the following: a mixture of poly(ethylene/ 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 atoms.
[0110] 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 Lewis acid catalyst such as
aluminium trichloride or boron trifluoride. These polybutenes
predominantly contain monomer repeating units of the
configuration
--C(CH.sub.3).sub.2CH.sub.2--
[0111] The hydrocarbyl substituent is attached to the succinic acid
moiety or derivative thereof via conventional means, for example
the reaction between maleic anhydride and an unsaturated
substituent precursor such as a polyalkene, as described for
example in EP-B-0 451 380.
[0112] One procedure for preparing the substituted succinic
acylating agents involves first chlorinating the polyalkene until
there is an average of at least 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.degree. C. to
about 125.degree. C. If desired, a diluent can be used in the
chlorination procedure. Suitable diluents for this purpose include
poly- and perchlorinated and/or fluorinated alkanes and
benzenes.
[0113] The second step in the procedure is to react the chlorinated
polyalkene with the maleic reactant at a temperature usually within
the range of about 100.degree. C. to about 200.degree. C. The mole
ratio of chlorinated polyalkene to maleic reactant is usually about
1:1. However, a stoichiometric excess of maleic reactant can be
used, for example, a mole ratio of 1:2. lf 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 maleic
reactant can react per molecule of chlorinated polyalkene. It is
normally desirable to provide an excess of maleic reactant; for
example, an excess of about 5% to about 50%, for example 25% by
weight. Unreacted excess maleic reactant may be stripped from the
reaction product, usually under vacuum.
[0114] 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 maleic 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 promote reaction of the remaining unreacted
maleic reactants. According to the patents, 0.3 to 2 or more moles
of maleic anhydride are used in the reaction for each mole of
polyalkene. The direct alkylation step is conducted at temperatures
to 180.degree. C. to 250.degree. C. During the chlorine-introducing
stage, a temperature of 160.degree. C. to 225.degree. C. is
employed.
[0115] 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 maleic 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.degree. C.
[0116] Usually, where the polyalkene is sufficiently fluid at
140.degree. 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.
[0117] 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.
[0118] The minimum temperature at which the reaction in the
one-step process takes place at a reasonable rate is about
140.degree. C. Thus, the minimum temperature at which the process
is normally carried out is in the neighbourhood of 140.degree. C.
The preferred temperature range is usually between about
160.degree. C. and about 220.degree. C. Higher temperatures such as
250.degree. C. or even higher may be used but usually with little
advantage. In fact, excessively high temperatures may be
disadvantageous because of the possibility that thermal degradation
of either or both of the reactants may occur at excessively high
temperatures.
[0119] In the one-step process, the molar ratio of maleic reactant
to chlorine is such that there is at least about one mole of
chlorine for each mole of maleic 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.
[0120] 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.
[0121] 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 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.
[0122] The present invention has discovered that the nature of the
polyamine, and in 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.
[0123] (1) polyalkylene polyamines of the general formula IV
(R.sup.6).sub.2N[U-N(R.sup.6)].sub.qN(R.sup.6).sub.2 IV
[0124] wherein each R.sup.6 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 R.sup.6 represents a hydrogen atom, q represents an
integer in the range from 1 to 10 and U represents a C.sub.1-18
alkylene group;
[0125] (2) heterocyclic-substituted polyamines including
hydroxyalkyl-substituted polyamines
[0126] wherein the polyamines are described above and the
heterocyclic substituent is for example a piperazine, an
imidazoline, a pyrimidine, or a morpholine; and
[0127] (3) aromatic polyamines of the general formula V
Ar(NR.sup.6.sub.2).sub.y V
[0128] wherein Ar represents an aromatic nucleus of 6 to about 20
carbon atoms, each R.sup.6 is as defined hereinabove and y
represents a number from 2 to about 8.
[0129] 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 polyamines include
N-(2-hydroxyethyl) ethylene diamine, N,N.sup.1-bis-(2-hydroxyethyl)
ethylene diamine, 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-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.
[0130] Many patents have described useful acylated nitrogen
compounds including U.S. Pat. Nos. 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 EP 0 263 703. A
typical and preferred compound of this class is that made by
reacting a poly(isobutylene)-subst- ituted 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 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.
[0131] 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).
[0132] More preferably, the polyamine mixture comprises at least
45% and preferably 50% by weight of polyamines having seven
nitrogen atoms per molecule, based on the total weight of
polyamines.
[0133] 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 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.
[0134] 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, 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 maleic 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 applications.
[0135] The reaction is typically carried out at conventional
temperatures in the range of about 80.degree. C. to about
200.degree. C., more preferably about 140.degree. C. to about
180.degree. C. These reactions may be conducted in the presence or
absence of an ancillary diluent or 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. 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 mm.sup.2/sec at 100.degree. C., with the
primarily paraffinic mineral oils, such as those in the range of
Solvent 90 to Solvent 150 Neutral, being preferred.
[0136] 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 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.
[0137] 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 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 U.S. Pat. Nos. 3,216,936 and
3,250,715.
[0138] 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
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
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 U.S. Pat. Nos. 2,812,342 and
3,260,671.
[0139] 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-stearic acids. Branched
chain fatty carboxylic acid/alkylene polyamine products have been
described extensively in the art. See for example, U.S. Pat. Nos.
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 condensates for their use in
oleaginous formulations.
[0140] 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.
[0141] Additive Composition
[0142] 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, 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; 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.
[0143] The detergents of the present invention may be incorporated
into the bulk fuel oil 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.
[0144] 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
present invention are incorporated , preferably by blending or
mixing, into the fuel oil contemporaneously or sequentially.
[0145] Co-Additives
[0146] 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 antistatic additives.
[0147] 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 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 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
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.
[0148] The Engines
[0149] The engines suitable in the use include compression-ignition
(diesel) engines such as those found in vehicles.
[0150] 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:
[0151] (i) a maximum engine speed of no more than 1000 rpm
(revolutions per minute) for four stroke engines, and of no more
than 2,500 rpm for two stroke engines;
[0152] (ii) a power output of greater than 200 bhp (brake
horse-power);
[0153] (iii) a cylinder bore dimension of greater than 150 mm for
four stroke engines, (such as greater than 200 mm) or of greater
than 100 mm for two stroke engines; and
[0154] (iv) a piston stroke of greater than 150 mm for four stroke
engines (such as greater than 250 mm) or of greater than 120 mm for
two-stroke engines.
[0155] The engines primarily suited to the use of the invention are
those four stroke 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 operating parameters may be used.
Such engines may also be found in marine or stationary applications
and railway applications.
[0156] 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) and (iii), and most
preferably the parameters (i), (ii), (iii) and (iv).
[0157] 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).
[0158] 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 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.
[0159] Of the two-stroke engines, particularly suitable engines are
those having a power 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.
[0160] The invention will now be illustrated with the following
examples:
EXAMPLE 1
[0161] 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 API CE and CF4 requirements.
[0162] Additives A and B were tested in each oil at the 1% and 10%
levels and the kinematic viscosities (at 40.degree. C.) of the
resulting compositions measured.
[0163] 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.
1TABLE 1 Viscosity Results Lubricity Oil Viscosity (KV @ 40.degree.
C.) Oil 1 Oil 2 Oil 101.3 98.62 Oil + Additive A (1%) 105.9 100.2
Oil + Additive A (10%) 118.5 112.6 Oil + Additive B (1%) 107.6
101.8 Oil + Additive B (10%) 121.6 117.9
Example 2
Engine testing
[0164] Additives A and B, along with further additive C, were
tested in a KH Deutz marine engine and the resulting engine
deposits and wear on the pistons, piston rings and cylinder liners
measured.
[0165] The engine had the following characteristics:
2 Type: Single cylinder Bore: 240 mm Stroke: 280 mm Speed: 900 rpm
Power: 225 kW
[0166] 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.
3TABLE 2 Engine Test Results Medium Quality High Quality
Lubricating Oil Lubricating Oil Parameter A + B.sup.1 A + C.sup.2
Ref 1 Ref 2 Ref 3 A + B Ref Piston Land & grooves, 60 33 115
134 197 177 161 Total weighed demerits.sup.3 Cylinder lacquers,
merits.sup.4 Full ring travel 9.45 9.35 9.35 8.93 8.78 8.25 8.06
Top 25% 8.76 8.39 8.46 7.50 7.67 6.44 6.05 Bore polish, %.sup.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.sup.nd Groove Fill, % 0 2
2 2 4 8 26 Footnotes to table: .sup.1Additive 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 polyoxyalkylene
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). .sup.2Additive combination A + C comprised a
corresponding formulation, but wherein 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. .sup.3Demerits refers to
the degree of deposition, i.e. the greater the demerits the poorer
(dirtier) the condition of the piston .sup.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 surface .sup.5bore polish not recorded for `A +
C`.
[0167] 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 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.
* * * * *