Note: Descriptions are shown in the official language in which they were submitted.
CA 02431242 2003-06-04
OVERBASED METALLIC SALT DIESEL FUEL ADDITIVE
COMPOSITIONS FOR IMPROVEMENT OF PARTICULATE TRAPS
This invention relates to novel fuel additive compositions. More particularly,
this invention relates to a metal salt additive composition which has been
found highly
effective in improving the quality of emissions from the combustion of diesel
fuels.
These additives are especially effective in improving the performance of
particulate
1o traps which are used in the exhaust systems of diesel engines, amongst
other uses.
Diesel engines equipped with particulate traps, mounted in the exhaust stream,
to "trap" or collect particulates in the exhaust to prevent their emission to
the
atmosphere are expected to be in greater use in the next few years.
Diesel engines running without particulate traps emit unburned hydrocarbons
(HC), carbon monoxide (CO), nitrogen oxides (NO,), and particulates, all of
which
are subject to current or proposed regulation. The problems of controlling
these
pollutants are compounded because there is a trade-off between particulates
and
nitrogen oxides -- when the combustion conditions are modified to favor low
nitrogen
oxides emissions, particulates are increased. Particulate traps are employed
to reduce
the severity of the particulate enussions.
It now appears that a combination of techniques, including diesel traps and
systems that use nitrogen oxides, will be required to meet realistic clean air
goals.
This manner of reducing particulates will be necessary because the techniques
available for NOX reduction, such as timing changes and exhaust gas
recirculation,
require a trade-off with particulates. The achievement of lower emissions of
NOR,
unburned hydrocarbons, and carbon monoxide, while controlling particulates
over
3o reasonable periods of time, continues to present a technical challenge.
CA 02431242 2003-06-04
2
Diesel particulates, their effect and control, are at the center of much
concem
and controversy. Their chemistry and environmental impact present complex
issues.
Generally, the diesel particulate matter is principally solid particles of
carbon and
metal compounds with adsorbed hydrocarbons, sulfates and aqueous species.
Among
the adsorbed species are aldehydes and polycyclic aromatic hydrocarbons. Some
of
these organics have been reported to be potential carcinogens or mutagens.
Unburned
hydrocarbons are related to the characteristic diesel odor and include
aldehydes such
as formaldehyde and acrolein. The need to control nano-particles is likely to
lead to
mandates requiring traps.
Unfortunately, increasing the recovery of particulates simply by modifying
trap
design or size would increase the rate of back pressure buildup within the
trap, which
causes increased fuel consumption and poor driveability. Moreover, control of
the
various pollutants seems to be interrelated, with reduction of one sometimes
increasing levels of another. By modifying combustion to achieve more complete
oxidation, decreases can be achieved for pollutants resulting from incomplete
combustion, but NO,, is typically increased under these conditions.
It is clear that diesel traps (either catalyzed or uncatalyzed) will be
required in
order to control particulates, especially where efforts are made to control
NOX.
The use of diesel traps and the need to improve them has resulted in a great
deal of research and a great number of patents and technical publications. The
traps
are typically constructed of metal or ceramic and are capable of collecting
the
particulates from the exhaust and withstanding the heat produced by oxidation
of
carbonaceous deposits which must be burned off at regular intervals.
This burning off, or regeneration, could occur by itself if the operating
temperature of the trap were sufficiently high. However, in the typical
situation, the
exhaust temperature is not constantly high enough, and secondary measures such
as
electrically heating to raise the trap temperature or using a catalyst on the
washcoat to
reduce the combustion temperature of particulates, have not been fully
successful.
CA 02431242633 2003-06
3
The use of organometallic salts and complexes to improve the operation of
diesel engine particulate traps is disclosed, for example, in U.S. Patent No.
5,344,467
issued September 6, 1994, which teaches the use of a combination of an
organometallic complex and an antioxidant. The organometallic complex is
soluble
or dispersible in the diesel fuel and is derived from an organic compound
containing
at least two functional groups attached to a hydrocarbon linkage.
W099/36488 published July 22, 1999 discloses fuel additive compositions
which contain at least one iron-containing fuel-soluble or fuel-dispersible
species in
synergistic combination with at least one alkaline earth group metal-
containing fuel-
soluble or fuel-dispersible species. This combination of metallic additives is
said to
improve the operation of the diesel particulate filter traps.
Also pertinent to the subject matter of this invention is U.S. Patent No.
4,946,609 issued August 7, 1990, which teaches the use of iron compounds such
as
ferrocehe, ferrocene derivatives and iron salts of organic acids as additives
for
lubricating oils used for diesel engines. It is taught that the presence of
the iron
compounds in the lubricating oil facilitates the regeneration of the diesel
particle
filters.
W094/11467 published May 26, 1994 teaches a method to improve the
operation of diesel traps through the use of a fuel additive comprising fuel-
soluble
compositions of a platinum group metal in effective amounts to lower the
emissions
of unburned hydrocarbons and carbon monoxide from the trap. The platinum group
metals comprise platinum, palladium, rhodium or iridium.
The present invention is based upon the discovery that a certain overbased oil
soluble metal salt additive composition with significant amounts of overbased
metal
content is a stable additive system and is effective in fuel in improving the
operation
of diesel engine particulate traps.
CA 02431242 2009-03-13
4
In accordance with the present invention, there has been discussed a fuels
additive overbased metallic salt composition effective in improving the
operation of
diesel engine particulate traps when added to a diesel fuel so as to provide 1-
25 ppm,
such as 2-10 ppm or 5-10 ppm, by weight metal in the fuel which comprises at
least
one oil soluble or oil dispersible metal salt of an acidic organic compound,
said salt
composition containing 5-85 wt.%, preferably 5-25, 5-50 or 20-50 wt.%, of a
stoichiometric excess of metal over that required to neutralize the anionic
portion of
the salt, the metal being selected from the group consisting of Ca, Fe, Mg,
Sr, Na, Ti,
Zr, Mn, Zn and Ce. Cerium and iron are preferred.
Improved diesel fuel oils containing 1-25 ppm metal from the metallic salt
compositions of this invention constitute further embodiments of this
invention.
Suitable fuel oils are described below.
A further embodiment comprises the method of improving the operation of a
diesel engine particulate trap by providing to the engine a diesel fuel
composition
containing additive compositions of this invention. In embodiments, the
invention
provides a method of improving the operation of a diesel engine particulate
trap by
providing to the engine a diesel fuel composition containing a fuel additive
metallic salt
concentrate composition, said salt concentrate composition being effective in
improving
the operation of diesel engine particulate traps when added to the diesel fuel
so as to
provide 1-25 ppm by weight of metal in the fuel and consisting of one oil
soluble or oil
dispersible overbased metal salt of an acidic organic compound, containing 5-
85 wt.% of
a stoichiometric excess of metal over that required to neutralized the anionic
portion of
the salt, the metal being Ca, Fe, Mg, Sr, Na, Ti, Zr, Mn, Zn or Ce, in a
normally liquid
petroleum or synthetic hydrocarbon or oxygenated hydrocarbon or alcohol
solvent,
wherein the active material is present in the concentrate in such amounts as
to provide
1-25 ppm iron when added to the fuel, this amount being between 20 and 80% of
the
concentrate.
~
CA 02431242 2009-03-13
4a
Stable solutions or dispersions of the additive compositions of this invention
in a suitable solvent comprise a further embodiment of this invention. Such
iWditive
concentrates will contain 20 to 80% of active material. The active materials
are
present in the solvent in such amounts so as to provide in the fuel 1-25 ppm
of metal.
Such solutions or dispersions remain stable over a broad temperature range.
The solvent used to prepare the stable additive solutions or dispersions may
generally be characterized as a normally liquid petroleum or synthetic
hydrocarbon or
oxygenated hydrocarbon or alcohol solvents, such as hexanol, 2-ethylkexanol or
isodecyl alcohol solvent. Typical examples include kerosene, hydrotneated
kerosene,
isoparaffinic and paraffinic solvents and naphthenic aliphatic hydrocarbon
solvents,
aromatic solvents, dimers and higher oligomers or propylene, butene and
similar
olefins and mixtures thereof. Commercial products such as "Solvesso",
"Varsol",
"Norpar" and "Isopar" are suitable. Such solvents may also contain functional
groups
CA 02431242633 2003-06
other than carbon and hydrogen provided such groups do not adversely affect
the
performance of the additive composition. Preferred are isoparaffinic and
paraffinic
hydrocarbon solvents. Preferably, the solvent has a flash point greater than
20 C,
more preferably greater than 4 C, most preferably greater than 55 C.
5
The metals suitable for forming the metal salt useful in the present invention
comprise calcium, iron, magnesium, strontium, sodium, titanium, zirconium,
manganese, zinc and cerium.
An overbased salt will contain a stoichiometric excess of metal species to
salt
anions. This excess metal may exist in one or a combination of forms including
oxides, hydroxides or mixed oxidic salts. Lattice-like polynuclear-metal
complexes
may also be present.
For overbased salts, the excess metal may be introduced, either intentionally
or
unintentionally, during the main reaction process of salt formation or
alternatively
may be introduced subsequent to this via post treatment. The elemental metal,
oxides
and hydroxides are common feedstocks for the overbasing process. Specifically
for
iron-based additives, the mixture can also be the iron salt combined with
organometallic iron compounds such as ferrocene and those described in DE
10043144C 1.
In one embodiment of the invention the additive is admixed with the diesel
fuel by direct addition, or as part of a concentrate w:ith other additives,
and the diesel
fuel is used to operate a diesel engine equipped with an exhaust system
particulate
trap. The diesel fuel containing the additive is contained in a fuel tank,
transmitted to
the diesel engine where it is burned, and the additive reduces the ignition
temperature
of exhaust particles collected in the exhaust system particulate trap. In
another
embodiment, the foregoing operational procedure is used except that the
additive
combination is maintained on board the apparatus being powered by the diesel
engine
(e.g., automobile, bus, truck, etc.) in a separate fuel additive dispenser
apart from the
diesel fuel. The additive is combined or blended with the diesel fuel during
re-filling
CA 02431242633 2003-06
6
of the diesel fuel tank. Typically, the additive is dispensed in the form of a
solution in
a hydrocarbon solvent. In this latter embodiment, the additive is maintained
in the
fuel additive dispenser and can form a part of a fuel additive concentrate
being
combined with the diesel. Other techniques comprise adding the additive
combination
into the intake or exhaust manifold or adding the additive to the fuel at fuel
depots
prior to filling the tank of the diesel powered vehicle.
The organic moiety of the metal salt compounds preferably contain at least one
hydrocarbyl group, for example, as a substituent on an aromatic ring. The term
t o "hydrocarbyl" as used herein means that the group concerned is primarily
composed
of hydrogen and carbon atoms and is bonded to the :remainder of the molecule
via a
carbon atom but does not exclude the presence of other atoms or groups in a
proportion insufficient to detract from the substantially hydrocarbon
characteristics of
the group. Advantageously, hydrocarbyl groups for use in accordance with the
invention are aliphatic groups, preferably alkyl or alkylene groups,
especially alkyl
groups, which may be linear or branched. The total number of carbon atoms in
the
organic moiety should be at least sufficient to impart the desired oil-
solubility or oil-
dispersibility.
Phenols, for use in the metal salts of this 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).
Preferred phenols may be derived from the formula
CA 02431242633 2003-06
7
OH
I
Ry
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.
The phenols are frequently used in sulfurized form. Sulfurized hydrocarbyl
phenols may typically be represented by the formula:
OH OH
sx Ry Ry
where x is generally from 1 to 4. In some cases, more than two phenol
molecules may
be linked by Sx bridges.
In the above formulae, hydrocarbyl groups represented by R are
advantageously alkyl groups, which advantageously contain 5 to 100, preferably
5 to
40, especially 9 to 12, carbon atoms, the average number of carbon atoms in
all of the
R groups being at least 9 in order to ensure adequate solubility in oil.
Preferred alkyl
groups are nonyl (tripropylene) 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
reaction
CA 02431242633 2003-06
~
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
sulfurization reaction may be effected by heating the alkyl phenol compound at
from
50 to 250, preferably at least 100, C. The use of elemental sulfur will
typically yield
a mixture of bridging groups -(S)x- as described above. If a sulfur halide is
used, the
sulfurization reaction may be effected by treating the alkyl phenol at from -
10 to 120,
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
l0 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
sulphurizing
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
heterocyclic amine (e.g., morpholine).
Details of sulfurization processes are well known to those skilled in the art.
Regardless of the manner in which they are prepared, sulfurized alkyl phenols
useful in preparing overbased metal compounds generally comprise diluent and
unreacted alkyl phenols and generally contain from 2 to 20, preferably 4 to
14, and
most preferably 6 to 12, mass % sulfur based on the mass of the sulfurized
alkyl
phenol.
As indicated above, the term "phenol" as used herein includes phenols that
have been modified by chemical reaction with, for example, an aldehyde, and
Mannich base-condensed phenols.
Aldehydes with which phenols may be modified include, for example,
formaldehyde, propionaldehyde and butyraldehyde. The preferred aldehyde is
CA 02431242633 2003-06
9
formaldehyde. Aldehyde-modified phenols suitable for use 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 are
described in GB-A-2 121432.
In general, the phenols may include substituents other than those mentioned
above provided that such substituents do not detract significantly from the
surfactant
properties of the phenols. Examples of such substituents are methoxy groups
and
halogen atoms.
Salicylic acids used for salicylate salts of 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
described
above 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.
Preferred substituents in oil-soluble salicylic acids from which overbased
detergents 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, preferably 9 to 30,
especially
14 to 20, carbon atoms.
Sulfonic acids used for metal sulfonate salts of this 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,
CA 02431242633 2003-06
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 3 to more than 100 carbon atoms, such as, for example,
haloparaffins,
5 olefins that may be obtained by dehydrogenation of paraffins, and
polyolefins, for
example, polymers of ethylene, propylene, and/or butene. The alkylaryl
sulphonic
acids usually contain from 7 to 100 or more carbon atoms. They preferably
contain
from 16 to 80, or 12 to 40, carbon atoms per alkyl-substituted aromatic
moiety,
depending on the source from which they are obtained.
When neutralizing 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 and viscosity control agents.
Another type of sulfonic acid that may be used in accordance with the
invention comprises alkyl phenol sulfonic acids. Such sulfonic acids can be
sulfurized. Whether sulfurized or non-sulfurized these sulfonic acids are
believed to
have surfactant properties comparable to those of sulfonic acids, rather than
surfactant
properties comparable to those of phenols.
Sulfonic acids suitable for use in accordance with the invention also include
alkyl sulfonic acids, such as alkenyl sulfonic acids. In such compounds the
alkyl
group suitably contains 9 to 100, advantageously 12 to 80, especially 16 to
60, carbon
atoms.
Carboxylic acids that may be used in accordance with the invention include
mono- and dicarboxylic acids. Preferred monocarboxylic acids are those
containing 1
to 30, 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. Other
examples
are tall oil fatty acid, soy acid and acid derived from rapeseed oil. Iso-
octanoic acid
CA 02431242633 2003-06
11
may, if desired, be used in the form of the mixture of C8 acid isomers sold by
ExxonMobil Chemical Co. under the trade name "Cekanoic". Other suitable acids
are
those with tertiary substitution at the a-carbon atom and dicarboxylic acids
with more
than 2 carbon atoms separating the carboxylic groups. Further, dicarboxylic
acids
with more than 35, for example, 36 to 100, carbon atoms are also suitable.
Unsaturated carboxylic acids can be suiphurized. Although salicylic acids
contain a
carboxylic group, for the purposes of the present invention they are
considered to be a
separate group of surfactants, and are not considered to be carboxylic acid
surfactants.
(Nor, although they contain a hydroxyl group, are they considered to be phenol
surfactants.)
Other acids are those formed by dimerizing fatty acids such as C36 dimer acid
and C12-C90, C12-C40 or C12-C24 succinic anhydride hydrolysis products or
acids
derived from polyalkenyl-maleic anhydride reaction products.
Preferred are metal salts of naphthenic acids which are monocarboxylic acids
related to the naphthene (alicyclic) series of hydrocarbons. The naphthenic
acids are
defined as monocarboxylic acids of the naphthene series of hydrocarbons. Their
general formula may be written R(CH2)õ COOH where R is a cyclic moiety
composed
of one or more rings. These rings are usually 5-membered (cyclo-pentene) and
may
be alkylated.
Examples of other compounds which may be used to provide metal salt
additives in accordance with the invention include the following compounds,
and
derivatives thereof: naphthenic acids, especially naphthenic acids containing
one or
more alkyl groups, dialkylphosphonic acids, dialkylthiophosphonic acids, and
dialkyldithiophosphoric acids, high molecular weight (preferably ethoxylated)
alcohols, dithiocarbamic acids, thiophosphines, and dispersants. Surfactants
of these
types are well known to those skilled in the art. Surfactants of the
hydrocarbyl-
substituted carboxylalkylene-linked phenol type, or dihydrocarbyl esters of
alkylene
dicarboxylic acids, the alkylene group being substituted with a hydroxy group
and an
additional carboxylic acid group, or alkylene-linked polyaromatic molecules,
the
CA 02431242633 2003-06
112
aromatic moieties whereof comprise at least one hydrocarbyl-substituted phenol
and at
least one carboxy phenol, may also be suitable for use in the present
invention; such
surfactants are described in EP-A-708 171.
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.
Preferred are metal salts derived from an acid compound of the formula
R3 RI
~ 1
R5-(C]Ei2)n C-(CH2)m C-COOH
I I
R4 R2
where Ri, R2, R3 and R4 represent hydrogen or a hydrocarbyl having 1-30 carbon
atoms
(C;-C30), but at least two of RI, Rz, R3 or R4 are Cl-C3Q hydrocarbyl; R5 is a
hydrocarbyl having 1 to 120 carbon atoms and m and n may each be zero or an
integer
such that the total number of carbon atoms in the carboxylate is not more than
125.
The formula above is intended to represent a carboxylic acid which has at
least two
side chains of at least 1 to 30 carbon atoms in length, and preferably both Rl
and R2
are hydrocarbyl so that the carboxylate is a neocarboxylate, i.e., having the
carbon
atom which is alpha to the carbonyl carbon connected to four other carbon
atoms and
iron neocarboxylates are preferred. The term hydrocarbyl is intended to apply
to
aromatic or aliphatic radicals composed principally of carbon and hydrogen,
CA 02431242633 2003-06
13
optionally substituted with oxygen or nitrogen, preferably aliphatic and
particularly
straight or branched chain alkyl or substituted alkyl, the substituents being
nitrogen or
oxygen. Most preferably the carboxylate is a neodecanoate and the metal is
preferably
iron.
Suitable examples of R5 moieties are hydrocarbyl groups 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
hydrocarbyl can also be derived from the halogenated (e.g. chlorinated or
brominated)
analogs of such homo- or interpolymers or from polyethers.
The hydrocarbyl is predominantly saturated. The hydrocarbyl is
predominantly aliphatic in nature, that is, containing 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 hydrocarbyl
contains
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 typical
substituents
are purely aliphatic. Typically, these purely aliphatic hydrocarbyls are alkyl
or alkenyl
groups.
A preferred source of the R5 moiety are poly(isobutene)s obtained by
polymerization of a C4 refmery stream having a butene content of 35 to 75 wt.%
and
isobutene content of 30 to 60 wt.% in the presence of a Lewis acid catalyst
such as
aluminum trichloride or boron trifluoride. These polybutenes predominantly
contain
monomer repeating units of the configuration -C(C.I:[3)2CH2-.
Any fuel having a boiling range and viscosity suitable for use in a diesel-
type
compression ignition engine may be used in this invention.
Such fuel oils include "middle distillate" fuel oil which refers to petroleum-
based fuel oils obtainable in refining crude oil as the fraction from the
light, kerosene
CA 02431242633 2003-06
=l4
or jet fuel, fraction to the heavy fuel oil fraction. These fuel oils may also
comprise
atmospheric or vacuum distillate, cracked gas oil or a blend, in any
proportions, of
straight run and thermally and/or catalytically cracked distillate. Examples
include
kerosene, jet fuel, diesel fuel, heating oil, visbroken gas oil, light cycle
oil, vacuum
gas oil and hydrocracked streams. Such middle distillate fuel oils usually
boil over a
temperature range, generally within the range of 100 C to 500 C, as measured
according to ASTM D86, more especially between 150 C and 400 C. Preferably,
the
diesel fuel will have less than 0.1 % by weight sulfur, inore preferably less
than 0.05%,
or less than 0.005%, or less than 0.001% by weight sulfur as determined by
ASTM D
lo 2622-87.
Preferred vegetable-based fuel oils are triglycerides of monocarboxylic acids,
for example, acids containing 10-25 carbon atoms, and typically have the
general
formula shown below
CH2OCOIZ
~
CHOCOR
CH2OCOR
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.
Suitable fuel oils also include mixtures of 1-50%, 1-25%, or 1-5% by weight
of vegetable oils or methylesters of fatty acid, such as tall oil fatty acids,
with
petroleum based diesel fuel oils. Also suitable are fuels emulsified with
water and
alcohols, which contain suitable surfactants, and residual fuel oil used in
marine diesel
engines.
CA 02431242633 2003-06
"15
Examples of oils are tall oil, rapeseed oil, coriander oil, soyabean oil, soya
oil,
corn 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, which is a mixture of fatty acids partially esterified with
glycerol, is
preferred as it is available in large quantities and can be obtained in a
simple way by
pressing from rapeseed.
Further preferred examples of vegetable-based fuel oils 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,
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 150, especially 90 to 125. Mixtures with particularly
advantageous properties are those which contain mainly, i.e. to at least 50 wt
%
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.
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, corn 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 wt % from unsaturated fatty acids with 18 carbon atoms, are preferred.
CA 02431242633 2003-06
16
Most preferred as a vegetable-based fuel oil is rapeseed methyl ester.
The inventive diesel fuel compositions can contain other additives which are
well known to those of skill in the art. These include dyes, cetane improvers,
rust
inhibitors such as alkylated succinic acids and anhydrides, bacteriostatic
agents, gum
inhibitors, metal deactivators, demulsifiers, upper cylinder lubricants, anti-
icing
agents, antioxidants and nitrogen containing ashless detergents such as
polyalkylene
amines and polyalkenyl succinimides.
The metal additive of this invention may also be used in combination with the
various lubricity additives which are now commonly used in low sulfur fuels.
Such
lubricity additives include monohydric or polyhydric alcohol esters of C2-C50
carboxylic acids such as glycerol monooleate, esters of polybasic acids with
Cy-Cs
monohydric alcohols, esters of dimerized carboxylic acids, reaction products
of
polycarboxylic acids and epoxides such as 1,2-epoxyethane and 1,2-epoxypropane
and
lubricity additives derived from fatty acids such as vegetable oil fatty acid
methyl
esters.;
Further examples are lubricity additives prepared by combining the aforesaid
esters of C2-C50 carboxylic acids with an ashless dispersant comprising an
acylated
nitrogen compound having a hydrocarbyl substituent of at least 10 carbon atoms
made
by reacting an acylating agent with an amino compound, such as the reaction
products
of polyisobutenyl (C80-C500) succinic anhydride with ethylene polyamines
having 3 to
7 amino nitrogen atoms.
Other lubricity additives are combinations of the aforesaid esters with
ethylene-unsaturated ester copolymers having, in addition to units derived
from
ethylene, units of the formula
-CRiR2-CHR3-
CA 02431242633 2003-06
17
wherein R' represents hydrogen or methyl; RZ represents COOR4, wherein R4
represents an alkyl group having from 1 to 9 carbon atoms which is straight
chain or,
if it contains 2 or more carbon atoms, branched, or R2 represents OOCRS,
wherein R5
represents R4 or H; and R3 represents H or COOR4. Examples are ethylene-vinyl
acetate and ethylene-vinyl propionate and other copolymers where there is
present 5-
40% of the vinyl ester.
As an alternative to the above described esters, or in combination therewith,
the lubricity additive may comprise one or more carboxylic acids of' the types
disclosed in relation to the ester lubricity additives or vegetable based fuel
oils. Such
acids may be mono- or polycarboxylic, saturated or unsaturated, straight or
branched
chain and may be generalized by the formula Rl(COOH)x where x is 1-4 and R' is
a
C2 to C50 hydrocarbyl. Examples are capric, lauric, myristic, palmitic, oleic,
elaidic,
palmitoleic, petaoselic, ricinoleic, linoleic, linolemic, eicosanic, tall oil
fatty and
dehydrated castor oil fatty acids. The polycarboxylic acid may be a dimer acid
such as
that fornmed by dimerization of unsaturated fatty acids such as linoleic or
oleic acid.
Other lubricity additives are hydroxy amines of the formula
R2 R3
il
(CH - CH)P O H
a
Rl-N\
(CH - CH)q H
L JI IS b
R4 R
where R 1 is an alkenyl radical having one or more double bonds or an alkyl
radical
and containing from 4 to 50 carbon atoms, or a radical of the forrnula
R6 R7
~ I
(CH - CH)v O H
c
R$N
\ R9
CA 02431242633 2003-06
lg
where each of R2, R3, R4, R5, R6 and R7 is independently hydrogen or a lower
alkyl
radical; R8 is an alkenyl radical having one or more double bonds or an alkyl
radical
and containing from 4 to 50 carbon atoms; R9 is an alkylene radical containing
from 2
to 35, e.g. 2 to 6, carbon atoms; each of p, q and v is an integer between 1
and 4; and
each of a, b and c may be 0, providing that at least one of a, b or c is an
integer
between 1 and 75.
The additives of the invention may also be used in combination with diesel
performance additives such as silicon-containing anti-foam agents such as
siloxane
block copolymers or cetane improvers such as 2-ethyl hexyl nitrate.
The additives of this invention may also be used in combination with cold
flow additives such as
an oil-soluble hydrogenated block diene polymer, comprising at least one
crystallizable block, obtainable by end-to-end polymerization of a linear
diene,
and at least one non-crystallizable block, the non-crystallizable block being
obtainable by 1,2-configuration polymerization of a linear diene, by
polymerization of a branched diene, or by a mixture of such polymerizations,
or
another cold flow improver as defined in (A) - (F) below.
(A) An ethylene-unsaturated ester copolymer, more especially one having, in
addition to units derived from ethylene, units of the formula
-CR3R4-CHRS-
wherein R3 represents hydrogen or methyl, R4 represents COOR6, wherein R6
represents an alkyl group having from 1 to 9 carbon atoms, which is straight
chain or,
CA 02431242633 2003-06
19
if it contains 3 or more carbon atoms, branched, or R4 represents OOCR7,
wherein R7
represents R6 or H, and R5 represents H or COOR6.
These may comprise a copolymer of ethylene with an ethylenically unsaturated
ester, or derivatives thereof. An example is a copolymer of ethylene with an
ester of a
saturated alcohol and an unsaturated carboxylic acid, but preferably the ester
is one of
an unsaturated alcohol with a saturated carboxylic acid. An ethylene-vinyl
ester
copolymer is advantageous; an ethylene-vinyl acetate, ethylene-vinyl
propionate,
ethylene-vinyl hexanoate, or ethylene-vinyl octanoate copolymer is preferred.
As disclosed in U.S. Patent No. 3961916, flow improver compositions may
comprise a wax growth arrestor and a nucleating agent. Without wishing to be
bound
by any theory, the applicants believe that component (i) of the additive
composition of
the invention acts primarily as a nucleator and will 'benefit from the
presence of an
arrestor. This may, for example, be an ethylene-unsaturated ester as described
above,
especially an EVAC with a molecular weight (Mn, measured by gel permeation
chromatography against a polystyrene standard) of at most 14000,
advantageously at
most 10000, preferably 2000 to 6000, and more preferably from 2000 to 5500,
and an
ester content of 7.5% to 35%, preferably from 10 to 20, and more preferably
from 10
to 17, molar percent.
It is within the scope of the invention to include an additional nucleator,
e.g.,
an ethylene-unsaturated ester, especially vinyl acetate, copolymer having a
number
average molecular weight in the range of 1200 to 20000, and a vinyl ester
content of
0.3 to 10, advantageously 3.5 to 7.0 molar per cent.
(B) A comb polymer.
Such polymers are polymers in which brancl:ies containing hydrocarbyl groups
are pendant from a polymer backbone, and are discussed in "Comb-Like Polymers.
Structure and Properties", N. A. Plate and V. P. Shibaev, J. Poly. Sci.
Macromolecular
Revs., 8, p 117 to 253 (1974).
CA 02431242633 2003-06
Generally, comb polymers have one or more long chain hydrocarbyl branches,
e.g., oxyhydrocarbyl branches, normally having from 10 to 30 carbon atoms,
pendant
from a polymer backbone, said branches being bonded directly or indirectly to
the
5 backbone. Examples of indirect bonding include bonding via interposed atoms
or
groups, which bonding can include covalent and/or electrovalent bonding such
as in a
salt.
Advantageously, the comb polymer is a homopolymer having, or a copolymer
lo at least 25 and preferably at least 40, more preferably at least 50, molar
per cent of the
units of which have, side chains containing at least 6, and preferably at
least 10,
atoms.
As examples of preferred comb polymers there may be mentioned those of the
15 general formula
D J
I ~
-[C-CH]m-[C-CH]n-
I! I I
EG KL
wherein D = R", COOR", OCOR", R12COORI 1, or OR",
E = H, CH3, D, or Ria,
G =HorD
20 J = H, Ri2, R12COOR11, or an aryl or heterocyclic group,
K = H, COOR12, OCORia, OR12 or COOH,
L = H, R12, COOR12, OCOR12, COOH, or aryl,
R" ? Cla hydrocarbyl,
R12 ? Ci hydrocarbyl or hydrocarbylene,
and m and n represent mole fractions, m being finite and preferably within the
range
of from 1.0 to 0.4, n being less than 1 and preferably in the range of from 0
to 0.6.
CA 02431242633 2003-06
21
R" 1 advantageously represents a hydrocarbyl group with from 10 to 30 carbon
atoms, while R12 advantageously represents a hydrocarbyl or hydrocarbylene
group
with from 1 to 30 carbon atoms.
The comb polymer may contain units derived from other monomers if desired
or required.
These comb polymers may be copolymers of maleic anhydride or fumaric or
itaconic acids and another ethylenically unsaturated monomer, e.g., an a-
olefin,
i including styrene, or an unsaturated ester, for example, vinyl acetate or
homopolymer
of fumaric or itaconic acids. It is preferred but not essential that equimolar
amounts
of the comonomers be used although molar proportions in the range of 2 to 1
and 1 to
2 are suitable. Examples of olefins that may be copolymerized with e.g.,
maleic
anhydride, include 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-
octadecene.
The acid or anhydride group of the comb polymer may be esterified by any
suitable technique and although preferred it is not essential that the maleic
anhydride
or fumaric acid be at least 50% esterified. Examples of alcohols which may be
used
include n-decan-l-ol, ndodecan-l-ol, n-tetradecan-l-ol, n-hexadecan-l-ol, and
noctadecan-l-ol. The alcohols may also include up to one methyl branch per
chain,
for example, 1-methylpentadecan l-ol or 2-methyltridecan-l-ol. The alcohol may
be a
mixture of normal and single methyl branched alcohols.
It is preferred to use pure alcohols rather than the commercially available
alcohol mixtures but if mixtures are used the R12 refers to the average number
of
carbon atoms in the alkyl group; if alcohols that contain a branch at the 1 or
2
positions are used R12 refers to the straight chain backbone segment of the
alcohol.
These comb polymers may especially be fumarate or itaconate polymers and
copolymers such for example as those described in EP-A-153176, EP-A-153177 and
-
EP-A-225688, and WO 91/16407.
CA 02431242633 2003-06
22
Particularly preferred fumarate comb polymers are copolymers of alkyl
fumarates and vinyl acetate, in which the alkyl groups have from 12 to 20
carbon
atoms, more especially polymers in which the alkyl groups have 14 carbon atoms
or in
which the alkyl groups are a mixture of C14/C16 alkyl groups, made, for
example, by
solution copolymerizing an equimolar mixture of fumaric acid and vinyl acetate
and
reacting the resulting copolymer with the alcohol or mixture of alcohols,
which are
preferably straight chain alcohols. When the mixture is used it is
advantageously a
1:1 by weight mixture of normal C14 and C16 alcohols. Furthermore, mixtures of
the
C14 ester with the mixed C14/C16 ester may advantageously be used. In such
mixtures,
the ratio of C14 to C14/C16 is advantageously in the range of from 1:1 to 4:1,
preferably
2:1 to 7:2, and most preferably about 3:1, by weight. The particularly
preferred comb
polymers are those having a number average molecular weight, as measured by
vapour phase osmometry, of 1,000 to 100,000, more especially 1,000 to 30,000.
Other suitable comb polymers are the polymers and copolymers of a-olefins
and esterified copolymers of styrene and maleic anhydride, and esterified
copolymers
of styrene and fumaric acid; rnixtures of two or more comb polymers may be
used in
accordance with the invention and, as indicated above, such use may be
advantageous.
Other examples of comb polymers are hydrocarbon polymers, e.g., copolymers of
ethylene and at least one a-olefin, the a-olefin preferably having at most 20
carbon
atoms, examples being n-decene-1 and n-dodecene-1. Preferably, the number
average
molecular weight of such a copolymer is at least 30,000 measured by GPC. The
hydrocarbon copolymers may be prepared by methods. known in the art, for
example
using a Ziegler type catalyst.
(C) Polar nitrogen compounds.
Such compounds are oil-soluble polar nitrogen compounds carrying one or
more, preferably two or more, substituents of the formula >NR", where R 13
represents a hydrocarbyl group containing 8 to 40 atoms, which substituent or
one or
more of which substituents may be in the form of a cation derived therefrom.
The oil
CA 02431242633 2003-06
23
soluble polar nitrogen compound is generally one capable of acting as a wax
crystal
growth inhibitor in fuels. it comprises for example one or more of the
following
compounds:
An amine salt and/or amide formed by reacting at least one molar proportion
of a hydrocarbyl-substituted amine with a molar proportion of a hydrocarbyl
acid
having from 1 to 4 carboxylic acid groups or its anhydride, the substituent(s)
of
formula >NR13 being of the formula -NR13R14 where R13 is defined as above and
RI4
represents hydrogen or R13, provided that R13, and R14 may be the same or
different,
1o said substituents constituting part of the amine salt and/or amide groups
of the
compound.
Ester/amides may be used, containing 30 to 300, preferably 50 to 150, total
carbon atoms. These nitrogen compounds are described in. US Patent No.
4,211,534.
Suitable aniines are predominantly C12 to C40 primary, secondary, tertiary or
quaternary amines or mixtures thereof but shorter chain amines may be used
provided
the resulting nitrogen compound is oil soluble, normally containing about 30
to 300
total carbon atoms. The nitrogen compound preferably contains at least one
straight
chain C8 to C40, preferably C14 to C24, alkyl segment.
Suitable amines include primary, secondary, tertiary or quatemary, but are
preferably secondary. Tertiary and quatemary amines only form amine salts.
Examples of amines include tetradecylamine, cocoamine, and hydrogenated tallow
amine. Examples of secondary aniines include dioctacedyl amine and
methylbehenyl
amine. Amine mixtures are also suitable such as those derived from natural
materials.
A preferred amine is a secondary hydrogenated tallow amine, the alkyl groups
of
which are derived from hydrogenated tallow fat coniposed of approximately 4%
C14,
31% C16, and 59% C.
Examples of suitable carboxylic acids and their anhydrides for preparing the
nitrogen compounds include ethylenedianiine tetraacetic acid, and carboxylic
acids
based on cyclic skeletons, e.g., cyclohexane-l,2-dicarboxylic acid,
cyclohexene-1,2-
CA 02431242633 2003-06
24
dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid and naphthalene
dicarboxylic
acid, and 1,4-dicarboxylic acids including dialkyl spirobislactones.
Cenerally, these
acids have about 5 to 13 carbon atoms in the cyclic moiety. Preferred acids
useful in
the present invention are benzene dicarboxylic acids e.g., phthalic acid,
isophthalic
acid, and terephthalic acid. Phthalic acid and its anhydride are particularly
preferred.
The particularly preferred compound is the amide-amine salt formed by reacting
1
molar portion of phthalic anhydride with 2 molar portions of dihydrogenated
tallow
amine. Another preferred compound is the diamide formed by dehydrating this
amide-amine salt.
Other examples are long chain alkyl or alkylene substituted dicarboxylic acid
derivatives such as amine salts of monoamides of substituted succinic acids,
examples
of which are known in the art and described in US Patent No. 4,147,520, for
example.
Suitable amines may be those described above.
Other examples are condensates, for example, those described in EP-A-
327427:
(D) A compound containing a cyclic ring system carrying at least two
substituents
of the general formula below on the ring system
-A-NR15Ri6
where A is a linear or branched chain aliphatic hydrocarbylene group
optionally
interrupted by one or more hetero atoms, and RIS and R16 are the same or
different and
each is independently a hydrocarbyl group containing 9 to 40 atoms optionally
interrupted by one or more hetero atoms, the substituents being the same or
different
and the compound optionally being in the form of a salt thereof.
Advantageously, A
has from 1 to 20 carbon atoms and is preferably a methylene or polymethylene
group.
Such compounds are described in WO 93/04148.
(E) A hydrocarbon polymer.
CA 02431242633 2003-06
Examples of suitable hydrocarbon polymers are those of the general formula
TH UH
II I I
_[C_C1v_jC_C]w_
I I I I
TT HU
wherein T= H or R21 wherein
5 R21= C1 to C40 hydrocarbyl, and
U = H, T, or aryl
and v and w represent mole fractions, v being within the range of from 1.0 to
0:0, w
being in the range of from 0.0 to 1Ø
Examples of hydrocarbon polymers are disclosed in WO 91/11488.
` Preferred copolymers are ethylene a-olefin copolymers, having a number
average molecular weight of at least 30,000. Preferably the oc-olefin has at
most 28
carbon atoms. Examples of such olefins are propylene, 1-butene, isobutene, n-
octene-
1, isooctene-1, n-decene-1, and n-dodecene-1. The copolymer may also comprise
small amounts, e.g., up to 10% by weight, of other copolymerizable monomers,
for
example olefins other than a-olefins, and non-conjugated dienes. The preferred
copolymer is an ethylene-propylene copolymer.
The number average molecular weight of the ethylene a-olefin copolymer is,
as indicated above, preferably at least 30,000, as measured by gel permeation
chromatography (GPC) relative to polystyrene standards, advantageously at
least
60,000 and preferably at least 80,000. Functionally no upper limit arises but
difficulties of mixing result from increased viscosity at molecular weights
above about
150,000, and preferred molecular weight ranges are from 60,000 and 80,000 to
120,
000.
CA 02431242633 2003-06
26
Advantageously, the copolymer has a molar ethylene content between 50 and
85 per cent. More advantageously, the ethylene content is within the range of
from 57
to 80%, and preferably it is in the range from 58 to 73%; more preferably from
62 to
71 %, and most preferably 65 to 70%.
Preferred ethylene-a-olefin copolymers are ethylenepropylene copolymers
with a molar ethylene content of from 62 to 71% and a number average molecular
weight in the range 60,000 to 120,000; especially preferred copolymers are
ethylene-
propylene copolymers with an ethylene content of from 62 to 71% and a
molecular
weight from 80,000 to 100,000.
The copolymers may be prepared by any of the methods known in the art, for
example using a Ziegler type catalyst. The polymers should be substantially
amorphous, since highly crystalline polymers are relatively insoluble in fuel
oil at low
temperatures.
`Other suitable hydrocarbon polymers include a low molecular weight ethylene-
a-olefin copolymer, advantageously with a number average molecular weight of
at
most 7500, advantageously from 1,000 to 6,000, and preferably from 2,000 to
5,000,
as measured by vapour phase osmometry. Appropriate cx-olefins are as given
above,
or styrene, with propylene again being preferred. Advantageously the ethylene
content is from 60 to 77 molar per cent, although for ethylene-propylene
copolymers
up to 86 molar per cent by weight ethylene may be employed with advantage.
(F) A polyoxyalkylene compound.
Examples are polyoxyalkylene esters, ethers, ester/ethers and mixtures
thereof,
particularly those containing at least one, preferably at least two, Ca to
C30 linear
alkyl groups and a polyoxyalkylene glycol group of molecular weight up to
5,000,
preferably 200 to 5,000, the alkyl group in said polyoxyalkylene glycol
containing
from 1 to 4 carbon atoms. These materials form the subject of EP-A-0061895.
Other
such additives are described in United States Patent No. 4,491,455.
CA 02431242633 2003-06
27
The preferred esters, ethers or ester/ethers are those of the general formula
R31-O(D) -0-R32
where R31 and R32 may be the same or different and represent
(a) n-alkyl-
(b) n-alkyl-CO-
lo (c) n-alkyl-O-CO(CH2)x or
(d) n-alkyl-O-CO(CH2)x-CO-
x being, for example, 1 to 30, the alkyl group being linear and containing
from 10 to
30 carbon atoms, and D representing the polyalkylene segment of the glycol in
which
the alkylene group has 1 to 4 carbon atoms, such as a polyoxymethylene,
polyoxyethylene or polyoxytrimethylene moiety which is substantially linear;
some
degree bf branching with lower alkyl side chains (such as in polyoxypropylene
glycol)
may be present but it is preferred that the glycol is substantially linear. D
may also
contain nitrogen.
Examples of suitable glycols are substantially linear polyethylene glycols
(PEG) and polypropylene glycols (PPG) having a molecular weight of from 100 to
5,000, preferably from 200 to 2,000. Esters are preferred and fatty acids
containing
from 10-30 carbon atoms are useful for reacting with the glycols to form the
ester
additives, it being preferred to use a C18-C24 fatty acid, especially behenic
acid. The
esters may also be prepared by esterifying polyethoxylated fatty acids or
polyethoxylated alcohols.
Polyoxyalkylene diesters, diethers, ether/esters and mixtures thereof are
suitable as additives, diesters being preferred for use in narrow boiling
distillates,
when minor amounts of monoethers and monoesters (which are often formed in the
manufacturing process) may also be present. It is preferred that a major
amount of the
CA 02431242633 2003-06
28
dialkyl compound be present. In particular, stearic or behenic diesters of
polyethylene
glycol, polypropylene glycol or polyethylene/ polypropylene glycol mixtures
are
preferred.
Other exarnples of polyoxyalkylene compounds are those described in
Japanese Patent Publication Nos. 2-51477 and 3-34790, and the esterified
alkoxylated
amines described in EP-A-117108 and EP-A-326356.
EXAMPLE
An overbased ferric salt of aC18 tallow acid was evaluated in the XUD9
engine test which measures the deposits indirectly using air flow and the
results are
expressed in percentage of air flow loss at a constant lift of the injection
needle of 0.1
mm. The higher the value reported, the worse the level of deposit. Also tested
was a
neutral iron salt of neodecanoic acid. Both salts were tested in a standard
diesel fuel
and in the same fuel also containing a polyisobutenyl succinimide fuel
detergent. The
results are in the Table.
Table
Fe in fuel, 10 Total Fe in Overbased Fe Ionic Fe XUD9
ppm additive in additive additive Detergent 0.1 mm lift
Fe Neodecanoate 6.0% 0.0% 6.0% None 93
200 ppm 86
Overbased iron 17.9% 14.8% 3.1% None 88
200 ppm 65
talloate
