Note: Descriptions are shown in the official language in which they were submitted.
WO 94/24237 PCT/US94104262
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A METHOD OF REDUCING BLUDGE AND
VARNISH PRECURSORS IN LUBRICATING OILS
Backcrround of the Invention
1. Field of the Invention
The present invention pertains to a method, apparatus and
compositions for removing sludge and varnish precursors
from a lubricating oil disposed within an internal
combustion engine and for improving the oxidative
stability of the lubricating oil. More particularly, the
invention pertains to a method, apparatus and
compositions for achieving this purpose by contacting the
oil with an insoluble compound having a dispersant
functional group and in some cases also an antioxidant
functional group. The compound may be in the form of a
porous slab, a thin film, or in the form of discrete
particles which are within a circulating oil system but
do not have a core substrate. These discrete particles
may be "encaged", i.e. held inside of some large
structural member by means of filter paper, wire mesh or
by some other suitable means.
2 Description of Related Art
It is known in the art that during the combustion of
fossil fuels, for example, gasoline or diesel fuel, in an
internal combustion engine, polar hydrocarbon
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2
contaminants are formed due to incomplete combustion of
the fuel. Typical contaminants include low molecular
weight polar alkyl compounds such as alcohols, aldehydes,
ketones, carboxylic acids, and the like. These
contaminants are sludge and varnish precursors which pass
into the lubricating oil with combustion blow-by gases
where they contact water in the oil and agglomerate to
form an emulsion which is commonly referred to as sludge.
Sludge and varnish precursors can also arise from oil
oxidation. The presence of sludge in the oil is
undesirable because it tends to increase oil viscosity,
promote the presence of varnish on hot engine parts, and
plug oil passageways. The most common solution in the
art for this problem has been to incorporate dispersants
and antioxidants in the lubricating oil to increase the
ability of the oil to suspend sludge. While this
decreases the detrimental effect on viscosity, varnish,
and passageway plugging, over time the ability of an oil
to protect an engine becomes limited. A particular
problem is that commonly used dispersants suspend the
sludge in such a finely divided form that the sludge
passes through oil filters and remains in the oil with
subsequent viscosity increase rather than being removed
by the filter. It would therefore be most desirable to
employ a method for removing sludge and varnish
precursors from a lubricating oil and thereby avoid the
undesired result of leaving the sludge suspended in the
oil.
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It is known from U.S. patent 5,042,61? that compounds
having dispersant functional groups can be used within
the oil circulation system of an internal combustion
engine when such compounds are incorporated on a
substrate. The present invention greatly improves on this
method since the need for a substrate is eliminated. This
substantially saves on the space required in an oil
filter and significantly increases the amount of space
available to accommodate removed sludge and varnish
precursors. Elimination of the substrate also represents
a cost savings. Retaining the particles of composition
having a dispersant functional group or an antioxidant
functional group on or between sheets of filter paper in
order to keep them from moving about is very different
from intimately depositing these compounds on a
substrate.
It has now been found that the presence of sludge can be
significantly decreased in circulating lubricating oils
by contacting the sludge and varnish precursors with
discrete particles of a composition having a dispersant
functional group with or without an antioxidant
functional group that is encaged within the circulating
oil system, but not intimately adhered to or immobilized
on a substrate. It is believed that the sludge and
varnish precursors complex with the dispersant functional
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group and become immobilized on the particles.
Preferably, the dispersant functional group is a
crosslinked polyethylene amine which is in the form of
discrete particles encaged within a conventional oil
filter.
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Summary of the Invention
The invention provides a method of reducing the presence
of sludge or varnish precursors in a lubricating oil
which comprises contacting a lubricating oil containing
sludge or varnish precursors with an oil insoluble, oil
wettable compound having a dispersant functional group
and in some cases an antioxidant functional group, which
compound is capable of complexing with sludge or varnish
precursors and which compound is in the form of a
plurality of discrete solid particles which are not
deposited on a substrate, thereby causing at least a
portion of the sludge or varnish precursors to become
immobili2ed on said particles.
The invention also provides a method for reducing the
presence of sludge or varnish precursors in a lubricating
oil by providing a plurality of oil insoluble, oil
wettable, solid particles comprising one or more
compounds having a dispersant functional group and in
some cases an antioxidant functional group, which
particles are capable of complexing with sludge or
varnish precursors; and encaging said particles in the
path of a lubricating oil circulating within an internal
combustion engine without adhering said particles to a
substrate, which encaging prevents the transmigration of
said particles to said internal combustion engine by the
lubricating oil.
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The invention also provides compounds having a dispersant
functional group and in some cases an antioxidant
functional group, which are capable of complexing with
sludge or varnish precursors and of reducing the presence
of sludge in a lubricating oil, which compounds comprise
polyamine polymers having a molecular weight in the range
of from about 100 to about 60,000 which are crosslinked
with a crosslinking agent selected from the group
consisting of metal alkoxides, silanes, silicates,
epoxides, quinones, and phenol-formaldehyde compounds.
Other suitable chain extending, cross-linking and
insolubilizing agents may be utilized as are known to
those skilled in the art.
The invention further provides an article of manufacture
for reducing the presence of sludge or varnish precursors
in a lubricating oil including a plurality of oil
insoluble, oil wettable, solid particles comprising one
or more compounds having a dispersant functional group
and in some cases an antioxidant functional group, which
particles are capable of complexing with sludge or
varnish precursors: and means for encaging said particles
in the path of a lubricating oil circulating within an
internal combustion engine without adhering said
particles to a substrate, which encaging means prevents
the transmigration of said particles to said internal
combustion engine by the lubricating oil.
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The invention still further provides an oil filter which
comprises, a hollow, oil impermeable housing having oil
ingress and oil egress means; and a plurality of oil
insoluble, oil wettable, solid particles in said housing,
said particles comprising one or more compounds having a
dispersant functional group and in some cases an
antioxidant functional group, which particles are capable
of complexing with sludge or varnish precursors: and
means for encaging said particles between said oil
ingress and oil egress means, such particles not having
been deposited on a substrate, which encaging means
prevents the removal of said particles from said housing
by a lubricating oil when such oil is within said
housing; and at least one filtering media selected from
the group consisting of chemically active filter media,
physically active filter media and inactive filter media.
In an aspect of the present invention there is provided a
method of reducing the presence of sludge or varnish
precursors in a lubricating oil which comprises contacting a
lubricating oil containing sludge or varnish precursors with
an oil insoluble, oil wettable crosslinked amine compound
having an antioxidant functional group or a dispersant
functional group, or an antioxidant functional group and a
dispersant functional group said compound capable of
complexing with sludge or varnish precursors and said
compound in the form of a plurality of discrete solid
particles encaged in a housing and within a path of the
lubricating oil, said particles not deposited on a
substrate, thereby causing at least a portion of the sludge
or varnish precursors to become immobilized on said
particles.
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Detailed Description of the Preferred Embodiment
In current practice dispersants are typically blended
within a motor oil and comprise a solubilizing group such
as polybutene and a functional group that complexes,
reacts or interacts with sludge, sludge presursors and
varnish precursors (hereinafter referred to as dispersant
functional group). Also, antioxidants are typically
blended within a motor oil and may comprise a
solubilizing group and an active antioxidant functional
group. An antioxidant functional group is a chemical
group that protects a lubricating oil from oxidation
without the need for a solubilizing group, although one
may be present. According to this invention, sludge and
varnish precursors can be removed from a lubricating oil
and antioxidation protection provided without the need
for a solubilizing group by incorporating an antioxidant
functional group and/or a dispersant functional group in
the form of discrete particles positioned in the path of
circulating engine oil. Contrary to the dispersants and
antioxidants blended in oil, the compounds containing a
dispersant functional group or antioxidant functional
group useful within the context of the present invention
are those which are oil insoluble but oil wettable.
Essentially any such dispersant functional group which
will complex with sludge or varnish precursors can be
used. Examples of suitable dispersant functional groups
are, separately or in combination, amines, polyamines,
WO 94/24237 PCT/US94I04262
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morpholines, oxazolines, piperazines, alcohols, polyols,
polyethers, or substituted versions thereof (e. g. alkyl,
dialkyl, aryl, alkaryl or aralkyl amines, etc.)
Preferred dispersant functional groups include
polyethylene amines, other substituted amines (e. g.
polypropylene amines), pentaerythritol, aminopropyl
morpholine, their derivatives, or mixtures thereof.
Examples of derivatives include, but are not limited to,
salts of these dispersant functional groups; reaction
products of these functional groups with sultones, cyclic
anhydrides, or their neutralized derivatives (e. g. metal
sulfonate or carboxylate salts): hydrocarbon insoluble
polymers bound to these functional groups; organic or
inorganic polymer matrices in which these functional
groups are bound or chemisorbed; and copolymers
containing these functional groups. Examples of these
include polymers which incorporate polyethylene amines or
polyolefins containing polyethylene amine in which the
hydrocarbon portion has been rendered porous and
insoluble. Polyethylene amines are a particularly
effective functional group. In the most preferred
embodiment, the useful compounds are crosslinked amines
having ethylene amine functionality. One preferred class
of polyethylene amines are those commercially available
from the Virginia Chemical group of Hoechst Celanese
Corporation as CorcatR grades P-12, P-18, P-150 and JP-
600. These have number average molecular weights ranging
from about 100 to about 60,000, preferably from about
WO 94/24237 ~ PCT/US94/04262
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1,000 to about 5,000 and more preferably from about 1,000
to about 3,000. Other amines include 2-
methylpentamethylene diamine, diethylene triamine,
triethylene tetraamine. The most preferred class of
amines includes Polyamine H, a bottoms product formed in
the manufacture of polyethylene amine which contains
approximately 6-8 ethylene groups and is commercially
available from Union Carbide. These amines are
preferably crosslinked by a crosslinking agent, for
example those selected from the group consisting of metal
alkoxides, silanes, silicates, quinones, and phenol-
formaldehyde compounds. The most preferred crosslinking
agent is benzoquinone. The most preferred antioxidant
functional group is benzoquinone.
The amount of dispersant functional group containing
compound used can vary broadly depending upon the amount
of sludge or sludge and varnish precursors in the oil.
However, although only an amount effective to reduce the
sludge and varnish precursor content of the lubricating
oil need be used, the amount will typically range from
about 0.1 to about 10 wt.%, preferably from about 0.2 to
about 2.0 wt.%, based on weight of the lubricating oil,
provided the dispersant functional group particles are
the only dispersant functional group in the system. The
dispersant functional group containing compound is in the
form of discrete particles which may have a particle size
ranging from about 0.001 mm to about 50 mm, preferably
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from about 0.01 mm to about 10 mm and most preferably
from about 0.1 mm to about 5 mm. The discrete particles
are positioned in the path of a lubricating oil
circulating within an internal combustion engine without
adhering or having deposited the particles on a
substrate. This is preferably done by encaging them
within a filter media to prevent the transmigration of
the particles to said internal combustion engine by the
lubricating oil. One method of encaging such particles
is to dispose them with or without a small amount of
binder polymer between sheets of conventional paper or
filter media in a typical oil filter. Another method may
be by enclosing the particles within a netting or screen
material. Any method of encaging is useful provided the
particles remain discrete, to expose essentially their
entire surface area to circulating oil, while preventing
the migration of the particles to the combustion chamber
of the engine. The particles can be located within or
external to the lubrication system of the internal
combustion engine. Preferably, the particles will be
located within the lubrication system such as on the
engine block or near the sump.
Sludge and sludge precursors are present in essentially
any lubricating oil used in the lubrication system of
essentially any internal combustion engine, including
automobile and truck engines, two-cycle engines, aviation
piston engines, marine and railroad engines, gas-fired
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12
engines, alcohol (e. g. methanol) powered engines,
stationary powered engines, turbines, and the like. The
sludge precursors are commonly produced as the result of
reaction between combustion by-products, fuel and
lubricant. Another source of sludge precursors is oil or
additive oxidation.
In addition to sludge and sludge presursors, the
lubricating oil will normally comprise a major amount of
lubricating oil basestock or lubricating base oil, and a
minor amount of one or more additives. The lubricating
oil basestock can be derived from natural lubricating
oils, synthetic lubricating oils, or mixtures thereof.
In general, the lubricating oil basestock will have a
viscosity in the range of about 5 to about 10,000 cSt at
40° C., although typical applications will require an oil
having a viscosity ranging from about 10 to about 1,000
cSt at 40° C.
Natural lubricating oils include animal oils, vegetable
oils (e. g. castor oil and lard oil), petroleum oils,
mineral oils, and oils derived from coal or shale.
Synthetic oils include hydrocarbon oils and halo-
substituted hydrocarbon oils such as polymerized and
interpolymerized olefine (e. g. polybutylenes,
polypropylenes, propylene-isobutylene copolymers,
chlorinated polybutylenes, poly(1-hexenes), poly(1-
octenes), poly(1-decenes), etc., and mixtures thereof);
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alkylbenzenes (e. g. dodecylbenzenes, tetradecylbenzenes,
dinonylbenzenes, di(2-ethylhexyl) benzene, etc.):
polyphenyls (e. g. biphenyls, terphenyls, alkylated
polyphenyls, etc.); alkylated diphenyl ethers, alkylated
diphenyl sulfides, as well as their derivatives, analogs,
and homologs thereof; and the like. Synthetic
lubricating oils also include alkylene oxide polymers,
interpolymers, copolymers and derivatives thereof wherein
the terminal hydroxyl groups have been modified by
esterification, etherification, etc. This class of
synthetic oils is exemplified by polyoxyalkylene polymers
prepared by polymerization of ethylene oxide or propylene
oxide; the alkyl and aryl ethers of these polyoxyalkylene
polymers (e. g. methyl-polyisopropylene glycol ether
having an average molecular weight of 1000, diphenyl
ether of polyethylene glycol having a molecular weight of
500-1000, diethyl ether of polypropylene glycol having a
molecular weight of 1000-1500): and mono- and
polycarboxylic esters thereof (e. g., the acetic acid
esters, mixed C3-Cg fatty acid esters, and C13 oxo acid
diester of tetraethylene glycol). Another suitable class
of synthetic lubricating oils comprises the esters of
dicarboxylic acids (e. g., phthalic acid, succinic acid,
alkyl succinic acids and alkenyl succinic acids, malefic
acid, azelaic acid, suberic acid, sebasic acid, fumaric
acid, adipic acid, linoleic acid dimer, malonic acid,
alkylmalonic acids, alkenyl malonic acids, etc.) with a
variety of alcohols (e. g. butyl alcohol, hexyl alcohol,
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dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol,
diethylene glycol monoether, propylene glycol, etc.).
Specific examples of these esters include dibutyl
adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate,
dioctyl sebacate, diisooctyl azelate, diisodecyl azelate,
dioctyl phthalate, didecyl phthalate, dieicosyl sebacate,
the 2-ethylhexyl diester of linoleic acid dimer, and the
complex ester formed by reacting one mole of sebacic acid
with two moles of tetraethylene glycol and two moles of
2-ethylhexanoic acid, and the like. Esters useful as
synthetic oils also include those made from C5 to C12
monocarboxylic acids and polyols and polyol ethers such
as neopentyl glycol, trimethylolpropane, pentaerythritol,
dipentaerythritol, tripentaerythritol, and the like.
Synthetic hydrocarbon oils are also obtained from
hydrogenated oligomers of normal olefins. Silicon-based
oils (such as the polyalkyl-, polyaryl-, polyalkoxy-, or
polyaryloxy-siloxane oils and silicate oils) comprise
another useful class of synthetic lubricating oils.
These oils include tetraethyl silicate, tetraisopropyl
silicate, tetra-(2-ethylhexyl) silicate, tetra-(4-methyl-
2-ethylhexyl) silicate, tetra(p-tert-butylphenyl)
silicate, hexa-(4-methyl-2-pentoxy)-disiloxane,
poly(methyl)-siloxanes and poly(methylphenyl) siloxanes,
and the like. Other synthetic lubricating oils include
liquid esters of phosphorus-containing acids (e. g.,
tricresyl phosphate, trioctyl phosphate, diethyl ester of
decylphosphonic acid), polymeric tetrahydrofurans.,
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polyalphaolefins, and the like.
The lubricating oil may be derived from unrefined,
refined, rerefined oils, or mixtures thereof. Unrefined
oils are obtained directly from a natural source or
synthetic source (e. g., coal, shale, or tar sands
bitumen) without further purification or treatment.
Examples of unrefined oils include a shale oil obtained
directly from a retorting operation, a petroleum oil
obtained directly from distillation, or an ester oil
obtained directly from an esterification process, each of
which is then used without further treatment. Refined
oils are similar to the unrefined oils except that
refined oils have been treated in one or more
purification steps to improve one or more properties.
Suitable purification techniques include distillation,
hydrotreating, dewaxing, solvent extraction, acid or base
extraction, filtration, and percolation, all of which are
known to those skilled in the art. Rerefined oils are
obtained by treating refined oils in processes similar to
those used to obtain the refined oils. These rerefined
oils are also known as reclaimed or reprocessed oils and
often are additionally processed by techniques for
removal of spent additives and oil breakdown products.
The lubricating base oil may contain one or more
additives to form a fully formulated lubricating oil.
Such lubricating oil additives include antiwear agents,
antioxidants, corrosion inhibitors, detergents, pour
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point depressants, extreme pressure additives, viscosity
index improvers, friction modifiers, and the like.
Typical additives are shown in U.S. Pat. No. 4,105,571.
Normally, there is from about 1 to about 20 wt.% of
these additives in a fully formulated engine lubricating
oil. Dispersants and antioxidants may also be included
as additives in the oil if desired, although this
invention partially or completely negates their need.
However, the precise additives used and their relative
amounts will depend upon the particular application of
the oil.
This invention can also be combined with the removal of
sludge or varnish precursors from a lubricating oil as
described in U.S. Patent 5,042,617 and discussed earlier
herein. This method provides for the incorporation of a
dispersant functional group immobilized by intimate
association with a substrate.
Any of the foregoing embodiments of the invention can be
combined with a system for reducing piston deposits in an
internal combustion engine which result from neutralizing
acids present in the lubricating oil of the engine. The
system provides a lubricating oil that circulates through
the lubrication system of the engine, and a soluble weak
base capable of neutralizing acids present in the oil to
form soluble neutral salts containing the weak base and
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the acids. There is a heterogeneous strong base
immobilized within the lubrication system of the engine,
the strong base being capable of displacing the weak base
from the soluble neutral salts such that the weak base is
returned to the lubricating oil and the resulting strong
base/acid salt is deposited or immobilized with the
heterogeneous strong base. This system is more fully
described in U.S. Patents 4,906,489 and 5,068,044.
This embodiment requires that a weak base be present in
the lubricating oil. The weak base will normally be
added to the lubricating oil during its formulation or
manufacture. Broadly speaking, the weak bases can be basic
organophosphorus compounds, basic organonitrogen
compounds, or mixtures thereof, with basic organonitrogen
compounds being preferred. Families of basic
organophosphorus and organonitrogen compounds include
aromatic compounds, aliphatic compounds, cycloaliphatic
compounds, or mixtures thereof. Examples of basic
organonitrogen compounds include, but are not limited to,
pyridines: anilines; piperazines: morpholines: alkyl,
dialkyl, and trialkyl amines; alkyl polyamines; and alkyl
and aryl guanidines. Alkyl, dialkyl, and trialkyl
phosphines are examples of basic organophosphorus
compounds. Examples of particularly effective weak bases
are the dialkyl amines (R2HN), trialkyl amines (RgN),
dialkyl phosphines (R2HP), and trialkyl phosphines (R3P),
where R is an alkyl group, H is hydrogen, N is nitrogen,
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and P is phosphorus. All of the alkyl groups in the
amine or phosphine need not have the same chain length.
The alkyl group should be substantially saturated and
from 1 to 22 carbons in length. For the di- and tri-
alkyl phosphines and the di- and tri- alkyl amines, the
total number of carbon atoms in the alkyl groups should
be from 12 to 66. Preferably, the individual alkyl group
will be from 6 to 18, more preferably from l0 to 18,
carbon atoms in length. Trialkyl amines and trialkyl
phosphines are preferred over the dialkyl amines and
dialkyl phosphines. Examples of suitable dialkyl and
trialkyl amines (or phosphines) include tributyl amine
(or phosphine), dihexyl amine (or phosphine), decylethyl
amine (or phosphine), trihexyl amine (or phosphine),
trioctyl amine (or phosphine), trioctyldecyl amine (or
phosphine), tridecyl amine (or phosphine), dioctyl amine
(or phosphine), trieicosyl amine (or phosphine),
tridocosyl amine (or phosphine), or mixtures thereof.
Preferred trialkyl amines are trihexyl amine,
trioctadecyl amine, or mixtures thereof, with
trioctadecyl amine being particularly preferred.
Preferred trialkyl phosphines are trihexyl phosphine,
trioctyldecyl phosphine, or mixtures thereof, with
trioctadecyl phosphine being particularly preferred.
Still another example of a suitable weak base is a
polyethyleneamine imide or amide of polybutenylsuccinic
anhydride with more than 40 carbons in the polybutenyl
group (see for example U.S. patent 5,164,101).
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The weak base must be strong enough to neutralise the
combustion acids (i.e., form a salt). Suitable weak
bases will typically have a PRa from about 4 to about
12. However, even strong organic bases (such as
orgaaoguaaidines) can be utilized as the weak base if
the strong base is an appropriate oxide or hydroxide
sad is capable of releasing the weak base from the
weak base/co~bustion acid salt.
The molecular weight of the weak base should be such that
the protonated nitrogen compound retains its oil
solubility. Thus, the weak base should have sufficient
solubility so that the salt formed remains soluble in the
oil and does not precipitate. Adding alkyl groups to the
weak base is the preferred method to ensure its
solubility. The amount of weak base in the lubricating
oil for contact at the piston ring zone will vary
depending upon the amount of combustion acids present,
the degree of neutralization desired, and the specific
applications of the oil. In general, the amount need
only be that which is effective or sufficient to
neutralize at least a portion of the combustion acids
present at the piston ring zone. Typically, the amount
will range from about 0.01 to about 3 wt. % or more,
preferably from about 0.1 to about 1.0 wt. %. Following
neutralization of the combustion acids, the neutral salts
are passed or circulated from the piston ring zone with
the lubricating oil and contacted with a heterogeneous
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strong base. By strong base is meant a base that will
displace the weak base from the neutral salts and return
the weak base to the oil for recirculation to the piston
ring zone where the weak base is reused to neutralize
combustion acids. Examples of suitable strong bases
include, but are not limited to, barium oxide (8a0),
magnesium carbonate (MgC03), magnesium hydroxide
(Mg(OH)2), magnesium oxide (Mg0), sodium aluminate
(NaAl02), sodium carbonate (Na2C03), sodium hydroxide
(NaOH), zinc oxide (Zn0), or their mixtures, with Mg0
being particularly preferred. By "heterogeneous" strong
base is meant that the strong base is in a separate phase
(or substantially in a separate phase) from the
lubricating oil, i.e., the strong base is insoluble or
substantially insoluble in the oil. The strong base may
be incorporated (e. g. impregnated) on or with a substrate
immobilized in the lubricating system of the engine, but
subsequent to (or downstream of) the piston ring zone.
Thus, the substrate can be located on the engine block or
near the sump. Preferably, the substrate will be part of
the filter system for filtering oil, although it could be
separate therefrom. Suitable substrates include, but are
not limited to, alumina, activated clay, cellulose,
cement binder, silica alumina, and activated carbon. The
alumina, cement binder, and activated carbon are
preferred, with cement binder being particularly
preferred. The substrate may (but need not) be inert.
The amount of strong base required will vary with the
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amount of weak base in the oil and the amount of
combustion acids formed during engine operation.
However, since the strong base is not being continuously
regenerated for reuse as is the weak base (i.e., the
alkyl amine), the amount of strong base must be at least
equal to (and preferably be a multiple of) the equivalent
weight of the weak base in the oil. Therefore, the
amount of strong base should be from 1 to about 15 times,
preferably from 1 to about 5 times, the equivalent weight
of the weak base in the oil. Once the weak base has been
displaced from the soluble neutral salts, the strong
base/strong combustion acid salts thus formed will be
immobilized as heterogeneous deposits with the strong
base or with the strong base on a substrate if one is
used. Thus, deposits which would normally be formed in
the piston ring zone are not formed until the soluble
salts contact the strong base. Preferably, the strong
base will be located such that it can be easily removed
from the lubrication system (e.g., included as part of
the oil filter system).
The presence of a strong base also serves to protect the
crosslinked dispersant functional group containing
composition of this invention from the acids generated by
an internal combustion engine. The crosslinked
dispersant functional group containing compositions used
by this invention are generally weakly basic. Thus when
such engine acids are carried to the filter, the
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crosslinked dispersant functional group containing
composition would be neutralized and lose its
functionality. The strong base would neutralize the
engine acids before they could neutralize the dispersant
functional group and hence protect them.
Any of the foregoing embodiments of this invention can be
combined with the removal of carcinogenic components from
a lubricating oil. For example, polynuclear aromatic
hydrocarbons (especially PNA's with at least three
aromatic rings) that are usually present in used
lubricating oil can be substantially removed (i.e.,
reduced by from about 60 to about 90% or more) by passing
the oil through a sorbent located within the lubrication
system through which the oil must circulate after being
used to lubricate the engine. The sorbent may be
immobilized with the substrate described above or
immobilized separate therefrom. Preferably, the substrate
and sorbent will be part of the engine filter system for
filtering oil. The sorbent can be conveniently located
on the engine block or near the sump, preferably
downstream of the oil as it circulates through the
engine: i.e., after the oil has been heated. Most
preferably, the sorbent is downstream of the substrate
when a substrate is present.
Suitable sorbents include activated carbon, attapulgus
clay, silica gel, molecular sieves, dolomite clay,
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alumina, zeolite, or mixtures thereof. Activated carbon
is preferred because it is at least partially selective
to the removal of polynuclear aromatics containing more
than 3 (and preferably 4, 5 and 6) aromatic rings: the
PNA's removed are tightly bound to the carbon and will
not be leached-out to become free PNA's after disposal;
the PNA's removed will not be redissolved in the used
lubricating oil: and heavy metals such as lead and
chromium will be removed as well. Although most activated
carbons will remove PNA's to some extent, wood and peat
based carbons are significantly more effective in
removing three and four ring aromatics than coal or
coconut based carbons. The amount of sorbent required
will depend upon the PNA concentration in the lubricating
oil. Typically, for a five quart oil change, about 20 to
150 grams of activated carbon can reduce the PNA content
of the used lubricating oil by up to 90%. Used
lubricating oils usually contain from about 10 to about
10,000 ppm of PNA's.
It may be necessary to provide a container to hold the
sorbent, such as a circular mass of sorbent supported on
wire gauze. Alternatively, an oil filter could comprise
the sorbent capable of combining with polynuclear
aromatic hydrocarbons held in pockets of filter paper.
Alternatively, the sorbent could be in the form of a
solid cyliader as in U.S. Patent 5,225,081.
CA 02160778 2004-03-16
24
Any of the foregoing embodiments of this invention can
also be combined with a sorbent, such as those described
above that is mixed, coated, or impregnated with
additives normally present in engine lubricating oils.
In this embodiment, additives, such as the lubricating
oil additives described above, are slowly released into
the lubricating oil to replenish the additives as they
are depleted during operation of the engine. The ease
with which the additives are released into the oil
depends upon the nature of the additive and the sorbent.
Preferably, however, the additives will be totally
released within 150 hours of engine operation. In
addition, the sorbent may contain from about 50 to about
100 wt.% of the additive, based on the weight of
activated carbon, which generally corresponds to 0.5 to
l.0 wt.% of the additive in the lubricating oil. Thus,
the various embodiments of this invention can be combined
to remove PNA's from a lubricating oil, to extend the
useful life of a lubricating oil by releasing
conventional additives into the oil, or both. A fuller
description of these embodiments of PNA removal and slow
release is presented in U.S. Patent 4,977,871.
This invention may also be combined with any method for
removing hydroperoxides from a lubricating oil by
CA 02160778 2004-03-16
- 25
contacting the oil with a heterogeneous hydroperoxide
decomposer for a period of time sufficient to cause a
reduction in the amount of hydroperoxides present in the
oil. Aydroperoxides are produced when hydrocarbons in
the lubricating oil contact the peroxides formed during
the fuel combustion process. As such, hydroperoxides
will be present in essentially any lubricating oil used
in the lubrication system of essentially any internal
combustion engine, including those mentioned above. U.S.
patents 4,997,546 and 5,112,482 disclose the use of
compounds, especially certain molybdenum compounds
which decompose hydroperoxides. These include
compounds such as MoS2, Mo4S4 (ROCSa) 6, and NaOH or
mixtures thereof. The compounds of U.S. 4,997,546 and
U.S. 5,112,482 function by being placed in a suitable
container, such as an oil filter where lubricating oil
is pumped over them and in which they decompose
hydroperoxides. The hydroperoxide decomposer is
immobilized when contacting the oil so as not to pass
into the oil. One preferred hydroperoxide decomposer
embodiment uses sodium hydroxide as described
in U.S. patent 5,209,839. More specifically, when the
hydroperoxide decomposer is heterogeneous NaOH,
hydroperoxides can be effectively removed from used
lubricating oil provided the oil also contains a metal
thiophosphate. The NaOH should be immobilized in some
manner when contacting the oil, for example in
WO 94/Z4237 PCT/US94/04262
- 26 - _
crystalline form or incorporated on a substrate to avoid
solids passing into the oil. In this preferred
embodiment, hydroperoxides are removed from lubricating
oil circulating within the lubrication system of an
internal combustion engine by contacting the oil with
crystalline NaOH immobilized within the lubrication
system.
The precise amount of hydroperoxide decomposes used can
vary broadly, depending upon the amount of hydroperoxide
present in the lubricating oil. However, although only
an amount effective or sufficient to reduce the
hydroperoxide content of the lubricating oil need be
used, the amount of decomposes will typically range from
about 0.01 to about 2.0 wt.%, although greater amounts
could be used. Preferably, from about 0.05 to about 1.0
wt.% (based on weight of the lubricating oil) of the
decomposes will be used. The hydroperoxide decomposes
should be immobilized in some manner when contacting the
oil. For example, it could be immobilized on a
substrate. However, a substrate would not be required if
the decomposes were in crystalline form. If a substrate
were used, the substrate may (or may not) be within the
lubrication system of an engine. Preferably, however,
the substrate will be located within the lubrication
system, for example on the engine block or near the sump.
More preferably, the substrate will be part of the filter
system for filtering the engine's lubricating oil,
WO 94/24237 PCTIUS94/04262
- - 27 -
although it could be separate therefrom. Suitable
substrates include, but are not limited to, alumina,
activated clay, cellulose, cement binder, silica-
alumina, and activated carbon. Alumina, cement binder,
and activated carbon are preferred substrates, with
activated carbon being particularly preferred. The
substrate may (but need not) be inert and can be formed
into various shapes such as pellets or spheres. The
decomposer may be incorporated on or with the substrate
by methods known to those skilled in the art. For
example, if the substrate were activated carbon, the
decomposer can be deposited by using the following
technique. The decomposer is dissolved in a volatile
solvent. The carbon is then saturated with the
decomposer containing solution and the solvent
evaporated, leaving the decomposer on the carbon
substrate.
When NaOH is used as the decomposer, the required metal
thiophosphates used preferably comprises a metal selected
from the group consisting of Group IB, IIB, VIB, VIII of
the Periodic Table, and mixtures thereof. A metal
dithiophosphate is a preferred metal thiophosphate, with
a metal dialkyldithiophosphate being particularly
preferred. Copper, nickel, and zinc are particularly
preferred metals, with zinc being most preferred. The
alkyl groups preferably comprise from 3 to 10 carbon
atoms. Particularly preferred metal thiopho~phates are
CA 02160778 2004-03-16
28
zinc dialkyl-dithiophosphates. The amount of metal
thiophosphate used in this invention can range broadly.
Typically, however, the concentration of the metal
thiophosphate will range from about 0.1 to about 2 wt.%,
preferably from about 0.3 to about 1 wt.%, of the
lubricating oil. NaOH and metal thiophosphates are
commercially available from a number of vendors. As
such, their methods of manufacture are well known to
those skilled in the art.
The foregoing invention may further be employed in
conjunction with an oil filter system which can be a one
stage or two stage filter. A typical oil filter
comprises a canister containing a chemically active
filter media, a physically active filter media, an
inactive filter media or combinations thereof. Most
preferably, the invention uses a two stage oil filter
containing, in series, a first filter media having a
chemically active filter media, a physically active
filter media, or mixtures thereof and a second filter
media having an inactive filter media can effectively
rejuvenate used lubricating oils. In a preferred
embodiment, the chemically or physically active filter
media will be within a canister that is separate from a
container having both active and inactive filter media.
This filter system is more fully described in U.S. patent
5,069,799. Aaother useful filtering system uses a hollow
CA 02160778 2004-03-16
- 29 -
solid composition composed of a thermoplastic binder
and an active filter media that contains a chemically
active or physically active filter media or both. Such
is more fully described in the aforesaid U.S. Patent
5,225,081. By "chemically active filter media" is meant
a filter media that chemically interacts with the used
lubricating oil (e. g., by chemical adsorption, acid/base
neutralization, and the like). By "physically active
filter media" is meant a filter media that interacts
with the lubricating oil by other than chemical
interaction (e.g., by physical adsorption). The
chemically active filter media will be or will contain a
chemically active~ingredient or ingredients, which may be
supported on a substrate or unsupported. If supported,
suitable substrates include those listed above. The
substrate may but need not be inert. One example of a
chemically active filter media is a filter media that is
or contains an oil insoluble, or substantially oil
insoluble, strong base. By "inactive filter media" is
meant a filter media that is inert and does not interact
with the lubricating oil except to remove particulates
from the oil. The-physically active filter media
includes the same substrates suitable for use with the
chemically active filter media as well as other
substrates such as attapulgus clay, dolomite clay, and
molecular sieves. An example of a physically active
filter media is a media such as activated carbon that can
remove polynuclear aromatics (PNA) from used lubricating
WO 94/24237 ~ ~ ~j PCT/US94104262
- 30 -
oil, especially PNA's with at least three aromatic rings.
Another example of a physically active filter media is
also disclosed in U.S. patent 4,977,871 wherein the
filter media is mixed, coated, or impregnated with one or
more additives normally present in lubricating oils.
These additives are oil soluble such that they will be
slowly released into the oil to replenish the additives
in the oil as they are depleted during its use of the
oil. Suitable inactive filter media may be found in
today's conventional engine oil filters and include
porous paper (e. g. pleated paper), glass fibers, spun
polymer filament, and the like. The inactive filter
media serves to retain and remove solid particles from
the oil. The precise amount of active filter media used
will vary with the particular function to be performed.
Although this invention has heretofore been described
with specific reference to removing sludge from
lubricating oils used in internal combustion engines,
and/or in providing antioxidation protection, it can also
be suitably applied to essentially any oil. For the
purpose of this invention, lubricating oil is defined to
include industrial oils, hydraulic oils and fluids,
automatic transmission oil, two cycle oils, gear oils,
power transmission fluids, and heat transfer oils that
contains polar hydrocarbon sludge or varnish precursors
from which sludge is formed. The invention may be
further understood by reference to the following examples
WO 94/24237 PCT/(JS94/04262
- 31 -
which are not intended to restrict the scope of the
appended claims. In these examples tests are used,
namely the Sludge Inhibition Bench (SIB) test for
measuring sludge performance and Differential Scanning
Calorimetry (DSC) for for measuring antioxidant
performance. The amount of soot in an oil sample may be
determined by thermal gravimetric analysis (TGA). TGA is
an analytical technique in which an oil sample suspended
on an arm of a thermobalance is heated and held within
the constant temperature zone of a furnace through which
a controlled atmosphere is passed. The loss or gain in
sample weight is measured as a function of a temperature
program applied to the furnace. The composition of the
gas flowing through the furnace can be changed during the
test run. A TGA procedure has been described by McGeehan
and Fontana (Effect of Soot on Piston Deposits and
Crankcase Oils--Infrared Spectrometric Technique for
Analyzing Soot, SAE paper, 801368, 1981). Another TGA
method is described in ASTM E1131, Standard Test Method
for Compositional Analysis by Thermogravimetry. The DSC
and SIB test procedures are as follows.
DSC Test
A test sample of known weight is placed in a DSC 30 Cell
(Mettler TA 3000) and continuously heated with an inert
reference at a programmed rate under an oxidizing air
environment. If the test sample undergoes an exothermic
or endothermic reaction or a phase change, the event and
WO 94/24237 ~ ~ ~ ~ ' PCT/US94/04262
- 32 -
magnitude of the heat effects relative to the inert
reference are monitored and recorded. More specifically,
the temperature at which an exothermic reaction begins
due to oxidation by atmospheric oxygen is considered as a
measure of the oxidative stability of the test sample.
The higher the DSC Break Temperature, the more
oxidatively stable the test sample. All DSC evaluations
are performed using the DSC cell at atmospheric pressure
and scanning temperatures from 50°C to 300°C (at least
25°C above the start of the temperature scan) to avoid
incorporating the initial heat flow between reference and
sample into the baseline measurement. The oxidation
onset temperature (or DSC Break Temperature) is the
temperature at which the baseline (on the exothermal heat
flow versus temperature plot) intersects with a line
tangent to the curve at a point one heat energy threshold
above the baseline. At times it is necessary to visually
examine the plot to identify the true heat energy
threshold for the start of oxidation.
SIB Test
A test oil is formed for the evaluation of filter
attractants by running a fully formulated non-dispersant
passenger car lubricant for 3000 miles is a Ford Taurus
for 3,000 miles of commuter operation. The test oil is
circulated through a filter assembly in a laboratory rig
and evaluated for the formation of sludge. In some cases
the filter assembly contains a filter attractant and in
CA 02160778 2004-03-16
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some cases it does not. After circulation in the lab
rig, two 10 gram samples of the oil are tested. The
first sample is centrifuged prior to a test run at 210oC
for 4 hours. The second sample is preheated to 138°C for
16 hours and then the test is run at 210°C for 4 hours.
The purpose of centrifugation is to remove separated
sludge but to leave sludge precursors. The sludge
precursors form additional sludge during the SIB test.
The supernatant after centrifugation is subjected to heat
cycling from about 150°C to room temperature over a
period of 4 hours at a frequency of about 2 cycles per
minute. During the heating phase, a gas containing a
mixture of about 0.7 volume percent of S02, 1.4 volume %
NO and the balance air is bubbled through the test
samples. During the cooling phase water vapor is bubbled
through the test samples. At the end of the test, the
liquid is centrifuged in weighed centrifuge tubes and the
amount of sludge separated from the supernatant is
determined and reported as milligrams of sludge. The
smaller the amount of separated/centrifuged sludge, the
more potent the filter attractant.
Polymer A:
TM
378.7 grams of Corcat P600, a polyethyleneamine
commercially available from Virginia Chemicals, are added
to 1563.5 grams of methanol and stirred until
WO 94124237 PCT/US94104262
- 34 -
homogeneous. 125.0 grams of
glycidoxypropyltrimethoxysilane are added and the
solution stirred for 20 minutes. 198.2 grams of
distilled water and 573.7 grams tetraethylorthosilicate
are added and the solution stirred until a gel forms.
The gel is removed from the flask and volatiles are
removed in a vacuum oven at 100° C and 0.5 mm Hg. The
product is refluxed in distilled water for 4 hours and
the wash decanted. The product is rinsed several times
with distilled water and decanted. The product is dried
in a vacuum oven at 100o C and 0.1 mm Hg overnight.
Nitrogen analysis: 9.53 wt %, Theory: 10%.
Polymer B:
179.6 grams of Polymer A are added to 1,323 grams
tetrahydrofuran and stirred until homogeneous. 49.7
grams of polyisobutylene succinic anhydride (PIBSA 48
available commercially from Exxon Chemical Company) are
added and the solution refluxed 3 hours. The wash is then
decanted, the solid rinsed with tetrahydrofuran and dried
in vacuum oven at 1100 C at 0.1 mm Hg overnight.
Polymer C
208 g formalin are added to 91 g phenol in a blaring
blender. High shear is begun and 200g Corcat P600 is
added. Gelation is almost instantaneous. The product is
WO 94/24237 PCT/US94104262
- 35 -
removed, immersed in liquid nitrogen and broken into a
powder. It is added to a vacuum oven at 1100 C/0.1 mm Hg
overnight. It is removed from the oven and added to 2
liters distilled water and refluxed overnight. The wash
is decanted, and the insoluble product rinsed with water
and dried in vacuum oven overnight at 110° C/O.1 mm Hg.
Nitrogen analysis: Theory: 15 wt%: Found: 10.8 wt%.
The polymers are evaluated for dispersant filter
performance in a lab filtration rig. Three tests are
used for measuring performance, Sludge Inhibition Bench
(SIB) for measuring sludge performance, Thermal
Gravimetric Analysis (TGA) for measuring soot/ash removal
and Differential Scanning Calorimetry (DSC) for measuring
antioxidant performance. The test consists of
circulating 100 ml of a non-dispersant but otherwise
fully formulated lubricant which has been used for 3000
miles in a Ford Taurus test car through a filter
containing 0.5 grams of the compound under test for 8
hours. The resulting oils are evaluated in a dispersant
SIB bench test and in DSC (oxidation stability). The
oils are also evaluated for Soot/Ash by TGA. The SIB data
are obtained for the samples both when not preheated, and
also where samples are preheated overnight. The
following results are observed and compared to other
filter attractants.
WO 94/24237 PCTIUS94I04262
- __
36 -
IMPROVEMENT RELATIVE TO REFERNCE OIL*
SMALL LAB RIG LARGE LAB RIG
$ $ DSC ~ $
ATTRACTANTTREAT $ REDUCTION MINUTES TREAT REDUCTION
POLYMER RATE ASH + SOOT INCREASERATE ASH/SOOT
SIB
A 0.5 37 62 +4 - -
B 0.9 10 79 10 2.4 34
C 0.5 +6 78 +6 - -
* The reference oil is obtained from a Ford Taurus test
car operated for 3,000 miles with the same non-dispersant
oil as Polymers A, B and C but with no polymer in the
filter. These data show that all of these compounds are
effective to remove sludge and varnish precursors.
EXAMPLE 2
Polymer D: Benzoquinone with 2-methylpentamethvlene
diamine
10.8 g benzoquinone (0.1 mole) are dissolved in 150 ml
methanol. 11.6 g 2-methylpentamethylene diamine (m. w.
116, 0.1 mole) are slowly added to the quinone solution
at room temperature. The resulting mixture is stirred at
room temperature for 24 hours and the solid precipitate
is filtered, washed with methanol and dried to yield 8.6
g.: mp > 300° C.
Polymer E' Benzoquinone with DETA (diethvlene triamine)
10.8 g benzoquinone (0.1 mole) is dissolved in 100 ml
methanol. 10.3g DETA (m. w. 103, 0.1 mole) are slowly
added to the quinone solution at room temperature. The
WO 94/24237 ~ ~ ~ PCT/US94/04262
- 37 -
resulting mixture is refluxed for 3 hours, allowed to
cool to room temperature and the solid precipitate is
filtered, washed with methanol and dried. Yield = 8 g.
Elemental analysis: C = 55.69%, H = 5.52%, N = 16.22%.
Polymer F' Benzoouinone with TETA ltriethylene tetramine)
amine.
10.8 g benzoquinone (0.1 mole) is dissolved in 100 ml
methanol 14.6 g TETA (m. w. 146, 0.1 mole) are slowly
added to the quinone solution at room temperature. The
resulting mixture is refluxed for 3 hours, allowed to
cool to room temperature and the solid precipitate is
filtered, washed with methanol and dried. Yield = 10 g.
Elemental analysis: C = 54.73%, H = 5.80%, N = 15.72%.
The polymers are tested as in Example 1 above with the
following results:
IMPROVEMENT RELATIVE TO REFERENCE OIL*
ATTRACTANTTREAT $REDUCTION $ REDUCTION DSC MINUTES
$
POLYMER RATE ASH/SOOT SIB INCREASE
D 0.9 31 62 56
E 0.5 3 70 87
F 0.5 3 75 58
* The same reference oil is used as in Example 1.
The SIB results clearly suggests that these quinone-amine
compositions are very effective in sludge reduction.
These data show that all of these compounds are effective
to remove sludge and varnish precursors.
WO 94/24237 PCT/US94104262
-
38 -
EXAMPLE 3
Polymer G:
163 grs. of benzoquinone is dissolved in methanol. 355
grs. of PAM are slowly added to the benzoquinone solution
at room temperature. The resulting solution is refluxed
for 2 hours, allowed to cool to room temperature and the
solid precipitate is filtered, washed with methanol and
dried.
Polymer G is evaluated for dispersant filter performance
in the lab filtration rig. The test used for measuring
performance was FT-IR, Fourier Transform Infrared
spectroscopy. A fresh oil fully formulated except that
it did not contain dispersant is compared by FT-IR with
the same oil after 3,000 miles service in a Ford Taurus
in commuter use. The increase in the integrated area of
absorbance in the OH stretching region, 3700-3100 cm-1,
34.09 units, is used as a measure of oil oxidation and
sludge formation during the 3,000 miles of commuter
service. 100 grs. of the 3,000 mile used oil is
circulated for 8 hours through a filter containing 0.5
grs. of polymer G. At the end of 8 hours the test oil is
compared to the fresh oil. The integrated area of
absorbance, 8 hour test oil vs. fresh oil is 10.95 units
representing a 68% reduction in oxidation products and
sludge in the used oil. The 68% reduction in oxidation
WO 94/24237 PCT/US94/04262
- 39 -
products and sludge measured by infrared is similar to
the 59% reduction in sludge measured by the SIB test for
a repeat preparation of Polymer G designated Polymer H.
Polymer H:
Benzoquinone with PAM (polyamine)
9.18 g benzoquinone (0.085 mole) are dissolved in 100 ml
methanol. 20 g PAM (8.5 meq/g primary amine, 0.17
equivalent) are slowly added to the quinone solution at
room temperature. The resulting solution is refluxed for
1 hour. The solution is then allowed to cool down to
room temperature and the precipitate solid is filtered,
washed with methanol and dried. Yield =
8.4 g. mp > 275°C. (Elemental analysis: C 55.54, H 6.22,
N 15.34)
Product I (This product is not a polymer):
Benzocruinone with Phenvlenediamine
10.8 benzoquinone (mw 108, 0.1 mole) is dissolved in 100
ml methanol. 10.8 g phenylenediamine (m.w. 108, 0.1
mole) are slowly added to quinone solution at room
temperature. The resulting solution is refluxed for 1
hour and allowed to cool down to room temperature. A
precipitate forms which is filtered, washed with methanol
and dried. Yield = 11.4 g. The product is insoluble in
mineral oil.
WO 94!24237 PCT/US94104262
40 -
~l~o~~~ - _
Polymer J:
Polythiophene
In a 500-ml three-necked flask, 32.4 g of iron
trichloride (FW162.2; 0.2 mole) are dissolved in 300 ml
of dry chloroform under nitrogen. A solution of 8.4 g
(0.1 mol) of thiophene in 20 ml of chloroform is then
added dropwise, and the mixture is stirred for 24 hours
at room temperature under nitrogen. A precipitate forms,
and is collected on a Buchner funnel, washed with
chloroform and dried. This polymer product is then
suspended in aqueous ammonium hydroxide (pH of ca. 10, pH
paper). The mixture is stirred for 12 hours at room
temperature under nitrogen, refiltered, washed with water
and dried. Yield 9.1 g.
Polymer K:
18.6 g (0.2 mol) aniline is dissolved in 600 ml 1 M HC1
and the solution is cooled to 0 to -5o C. A solution of
9.2 g (0.04 mol) ammonium peroxydisulfate, (NH4)2S2Og, in
100 ml 1 M HC1 is then added dropwise with vigorous
stirring during a period of 10 minutes. The temperature
is maintained at 5o C. Ten to fifteen minutes after the
reactants are mixed, the solution starts to show a green
tint and becomes intensely green as a precipitate forms.
The solution is filtered overnight at room temperature.
The mixture is filtered and the precipitate cakes are
washed with 500 ml of 1 M HC1 until the filtrate becomes
colorless. Upon drying under dynamic vacuum at room
WO 94/24237 PCT/US94/04262
- ~~fiUl~l
- 41 -
temperature for 24-48 hours, polyaniline hydrochloride is
obtained.
To convert polyaniline hydrochloride into polyaniline
base, the hydrochloride is suspended in aqueous NH40H
(approximately 100 ml of 0.1 M aqueous solution of NH40H
are used per gram of the hydrochloride) with stirring for
16 hours at room temperature. The pH of the solution is
periodically adjusted to ca. 10 (pH paper) by the
addition of a small amount of 1 M NH40H. The suspension
is then filtered and the precipitate is washed out with
ca. 400 ml of 0.1 M a NH40H followed by five 50 ml of a
1:1 mixture of methanol and 0.2M NaOH. The polymer base
is dried under vacuum at room temperature for 48 hours.
Benzocruinone with Polv (ethyleniminel
Polymer L:
8.6 g polyethylenimine in 50 ml water are mixed with 10.8
g benzoquinone (0.1 mole) suspended in 500 ml water. The
solution is stirred at room temperature for 24 hours.
Filter the product. Yield = 16 g.
Polymer M:
8.6 g polyethylenimine in 50 ml water are mixed with 10.8
g benzoquinone (0.1 mole) in 500 ml methanol. The
solution is stirred at room temperature for 24 hours.
Filter the product. Yield = 11.90 g.
WO 94124237 PCT/US94/04262
42 -
Polymer N:
9.18 g benzoquinone (0.085 mole) is dissolved in 500 ml
methanol. 96 g Corcat (9.82 meg/g primary amine, 0.17
equivalent) are slowly added to the quinone solution at
room temperature. The resulting solution is refluxed for
1 hour at temperature 70°C. Then the solution is allowed
to cool down to room temperature and the precipitate
solid is filtered, washed with methanol and dried.
IMPROVEMENT TO REFERENCEOIL*
RELATIVE
$ $ REDUCTION $ REDUCTION$ DSC
ATTRACTANT TREAT ASH + SOOT SIB MINUTES
POLYMER RATE INCREASE
H 0.5 27 59 10
I 0.5 56 32 59
J 0.5 21 29 44
K 0.5 18 32 41
L 0.5 24 43 11
M 0.5 13 0 12
N 0.5 46 18 49
* The same reference oil is used as in Example 1.
These data show that all of these compounds are effective
to remove sludge end varnish precursors.
WO 94/24237 ~ ~ PCTIUS94I04262
- 43 -
EXAMPLE 4
POLYAMINE/SILICON OXIDE COMPOSITE SYNTHESIS
To a tared (2228.0 g) 12-liter round bottom flask are
added 378.75 g (2.08 x 10-3) Corcat P600 (formula weight
60,000) polyethyleneamine (Virginia Chemical) and 1563.5
g methanol. The flask is equipped with an overhead
stirrer and the components are stirred until homogeneous.
125.0 g of gamma- glycidoxypropyltrimethoxysilane (Huels
America) are added and the mixture is stirred for 20
minutes. 198.25 g of deionized water are added and it is
stirred to homogenize the solution. 573.75 g of
tetraethylorthosilicate (Aldrich Chemicals) are added and
stirring is allowed to continue until a gel is formed.
The gel is removed from the flask, added to a vacuum oven
at 100°C and .imm Hg until the volatiles are gone. The
final dry product weighs 381.73 g. The product is
refluxed in distilled water for 4 hours and the wash
decanted. It is then rinsed several times with distilled
water over a sintered glass funnel. The material is
dried in a vacuum oven 100°C/0.1 mm Hg to produce a
powder weighing 366.72 g. Nitrogen Analysis: wt%
Nitrogen (theory/found) approximately 10/9.53.
EXAMPLE 5
179.66 g of the product from Example 4: 49.7 g of
polyisobutylene succinic anhydride (PIBSA 48) and 1323 g
WO 94/24237 PCT/US94/04262
__
44
of tetrahydrofuran are added to a 5-liter round bottom
flask equipped with an overhead chilled water condenser,
stirring rod with motor and heating mantle below. This
is refluxed 3 hours (added a few boiling stones prior to
refluxj, and the wash decanted. The solid is rinsed by
adding the wash back to the flask with fresh
tetrahydrofuran and the wash decanted. It is dried in a
vacuum oven at 110°C/0.1 mm Hg overnight. Total mass =
174 g of solid.
EXAMPLE 6
POLYAMINE GEL SYNTHESIS
208.32 g of formalin, and 91.64 g of phenol are added to
a quart sized waning blender. Mixing at high speed is
begun and 200 g of Corcat P600 are added. A gel forms
almost immediately. The gel is removed, frozen with
liquid nitrogen, broken into powder and added to an oven
at 110°C and 0.1 mm Hg overnight. When removed from the
oven the product weighs 134.15 g. The product and
approximately 2 liters of distilled water are added into
a flask equipped with condenser, stirrer and heating
mantle. It is refluxed overnight, the wash decanted,
rinsed twice and placed in vacuum oven overnight at
110°C/0.1 mm Hg. The dried product -weighs 129.5 g.
Nitrogen analysis: wt~ nitrogen:
theory: approximately 15%: found: 10.85.
PCT/US94/04262
WO 94124237
- 45 -
IMPROVEMENT RELATIVE TO REFERENCE OIL*
SIB TEST MGS. SLUDGE
ATTRACTANT PROCEDURE 1 PROCEDURE 2
Reference oil 15 10.8
Example 4 4.9 4.9
Example 5 3.0 3.8
Example 6 3.8 3.8
* The same reference oil is used as in Example 1. The
lower the result, the better the performance. Under
Prodecure 1, the samples are not preheated and the test
is run at 210°C for 4 hours. Under Procedure 2, the
samples are preheated to 138°C for 16 hours and then the
test is run at 210°C for 4 hours. These data show that
all of these compounds are effective to remove sludge and
varnish precursors.
EXAMPLE T
410.08 g Corcat P600 and 81.84 g Vikolox 16 are added to
a blaring blender and stirred for 5 minutes. 68.8 g of
gamma- glycidoxypropyltrimethoxysilane is then added, and
gelation follows within about a minute. Gel is removed,
weighed, (547.9 g), added to an oven, and heated under
nitrogen purge at 100° C for 8 hours. 301.53 g of dried
product is recovered. Dried product is added to a 5-liter
WO 94124237 ~ ~ ~ ~; ~~ ~., PCT/US94I04262
- 46 -
flask, followed by excess methanol and refluxed for 4
hours. The wash is decanted, the solid collected, and
dried under vacuum to 60o C/ 0.1 mm Hg for 8 hours.
Nitrogen theory: approximately 15 wt%. Found 15.37 wt%.
EXAMPLE 8
415.08 g Corcat P600 NS 60.0 g Vikolox are added to a
blaring blender and stirred for 5 minutes. 5.0 g 1,4-p-
benzoquinone (delivered as approximately 10 wt%
suspension in deionized water) is added and stirring
continued for 2 minutes. 68.8 g of gamma-
glycidoxypropyltrimethoxysilane is added and gelation
follows within a minute. Gel is removed, weighed (609.3
g), added to an oven, and heated under a nitrogen purge
at 90o C for 24 hours. The product is removed from the
oven, refluxed in excess methanol and the wash decanted.
The recovered solid is added to the oven at 90° C and
nitrogen purged for 2 hours. The nitrogen purge is
replaced with a vacuum line and the product dried
overnight at 90° C/0.1 mm Hg overnight. The product
yield is 228 g (84 wt% of theoretical). Nitrogen theory:
18 wt%, found 16.1 wt%.
