Note: Descriptions are shown in the official language in which they were submitted.
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DIESEL ENGINE OILS
FIELD OF INVENTION
The present invention relates to lubricating oil compositions. More
specifically, it relates to
lubricating oil compositions for use in railroad diesel engines or inland
marine engines.
BACKGROUND OF THE INVENTION
Lead bearing corrosion in locomotive engines has been a concern for original
equipment
manufacturers (OEMs). Total Base Number (TBN) retention has also been a
technical challenge.
Historically, railroad engine oils (RREO) are non-zinc containing formulations
because of the silver
bearings which were used in some locomotive engines. Without the benefit of
zinc dialkyl
dithiophosphate, the proper detergent mixture has been the key factor in
control of TBN retention and
lead corrosion.
In March 2008, the Environmental Protection Agency (EPA) finalized a three-
part program that will
dramatically reduce emissions from diesel locomotives of all types -- line-
haul, switch, and passenger
rail. The rule will decrease particulate matter (PM) emissions from these
engines by as much as 90
percent and NOx emissions by as much as 80 percent when fully implemented.
This final rule sets
new emission standards for existing locomotives when they are remanufactured.
The rule also sets
Tier 3 emission standards for newly-built locomotives, provisions for clean
switch locomotives, and
idle reduction requirements for new and remanufactured locomotives. Finally,
the rule establishes
long-term, Tier 4, standards for newly-built engines based on the application
of high-efficiency
catalytic aftertreatment technology, beginning in 2015.
Due to new EPA emission requirements and the introduction of ultra low sulfur
diesel (ULSD) fuel,
there will be a move to low SAPS railroad engine oils. As in heavy duty diesel
oils for truck engines,
there will be a decrease in TBN as well as a reduction in sulfur levels.
Traditionally RREOs were 13 ¨
17 TBN oils. The TBN will likely be lowered to 8-11 TBN due to these changes.
Balancing
reductions in TBN and sulfur with long standing concerns about TBN retention
and lead corrosion
will require a different formulation. It has been found that when TBN levels
were lowered, but the
components were not changed, TBN retention and lead corrosion levels suffered.
A problem exists
of maintaining or improving lead corrosion and TBN retention when TBN in the
oils and sulfur are
decreased in RRE0s.
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It has been discovered that formulations containing salicylate detergent in
addition to the traditional
components showed decreased levels of lead corrosion and better TBN retention.
Prior Art
Research Disclosure No. RD0493012 teaches the use of salicylate detergents and
supplementary
antioxidants for improved lead corrosion in low sulfated ash, phosphorus and
sulfur heavy-duty diesel
formulations.
Tomomi et al, JP 3925978 teaches a composition which comprises lubricating
base oil, (a)perbasic
alkali earth metal salicylate, (b)perbasic alkali earth metal phenate and
(c)bis-type alkenyl
succinimide, bis-type alkyl succinimide or their boron adducts.
Locke, EP 1256619 teaches a lubricating oil composition comprising (A) an oil
of lubricating
viscosity, in a major amount, and added thereto, (B) a detergent composition
comprising one or more
metal detergents which comprises metal salts of organic acids, in a minor
amount, wherein the
detergent composition comprises more than 50 mole % of a metal salt of an
aromatic carboxylic acid,
based on the moles of the metal salts of organic acids in the detergent
composition, and (C) one or
more co-additives, in a minor amount; wherein the total amounts of phosphorus
and sulfur derived
from (B) or (C) or both (B) and (C) are less than 0.1 mass % of phosphorus and
at most 0.5 mass % of
sulfur, based on the mass of the oil composition.
Shaw, U.S. Published Patent Application 2006/0052254 teaches an oil
composition, which contains a
salicylate, having sulfur (up to 0.3 wt%), phosphorus (up to 0.08 wt%),
sulfated ash (up to 0.80 wt%),
comprises a mixture of an oil of lubricating viscosity (a); and an overbased
alkali or alkaline earth
metal alkyl salicylate lubricating oil detergent (b) having salicylate soap
(20 - 25 wt%).
Reiff, U.S. Patent No. 2,197,832 teaches a mineral oil composition which
incorporates a small
quantity of a multifunctional compound selected from that group of class of
metalorganic compounds
which is referred to as the oil-soluble or oil-miscible metal salts of alkyl-
substituted hydroxyaromatic
carboxylic acids.
Yagishita, U.S. Patent No. 7,563,751 teaches a lubricating oil composition
comprising a base oil
having a sulfur content adjusted to 0.1 wt% or less, and at least one of two
different alkali or alkali
earth metal salicylate mixtures.
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Yasushi, Japanese Patent No., JP 2007217607 teaches a diesel engine oil which
contains mineral oil
and/or synthetic oil as base oil, salicylate type cleaning agent (1-8 mass%)
and diphenylamine
derivative (0.005-0.03 mass%) as additive.
SUMMARY OF THE INVENTION
One embodiment of the present invention is directed to alubricating oil
additive composition
comprising
a. a first carboxylate detergent having a TBN of the actives of greater
than about 200 to
about 400;
b. a second carboxylate detergent having a TBN of the actives of greater
than about 60
to about 200; and
c. at least one polyalkenyl succinimide.
One embodiment of the present invention is directed to a lubricating oil
composition comprising
a. a major amount of oil of lubricating viscosity;
b. a first carboxylate detergent having a TBN of the actives of greater
than about 200 to about
400;
c. second carboxylate detergent having a TBN of the actives of greater
than about 60 to about
200; and
d.at least one polyalkenyl succinimide.
One embodiment of the present invention is directed to a method for operating
a diesel locomotive
engine comprising lubricating said diesel locomotive engine with a lubricating
oil composition
comprising
a. a major amount of an oil of lubricating viscosity; and
b. a first carboxylate detergent having a TBN of the actives of greater
than about 200 to about
400;
c. a second carboxylate detergent having a TBN of the actives of
greater than about 60 to about
200; and
d. at least one polyalkenyl succinimide.
One embodiment of the present invention is directed to a method for operating
an inland marine
engine comprising lubricating said inland marine engine with a lubricating oil
composition
comprising
a. a major amount of an oil of lubricating viscosity; and
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b. a first carboxylate detergent having a TBN of the actives of greater
than about 200 to about
400;
c. a second carboxylate detergent having a TBN of the actives of greater
than about 60 to about
200; and
d. at least one polyalkenyl succinimide.
One embodiment of the present invention is directed to a method of improving
TBN retention
comprising lubricating an engine with a lubricating oil composition having
1. a major amount of an oil of lubricating viscosity;
2. a first carboxylate detergent having a TBN of the actives of greater
than about 200 to about
400;
3. a second carboxylate detergent having a TBN of the actives of greater
than about 60 to about
200; and
4. at least one polyalkenyl succinimide.
Detailed Description of the Invention
Definitions
The term "alkaline earth metal" refers to calcium, barium, magnesium,
strontium, or mixtures thereof.
The term "alkyl" refers to both straight- and branched-chain alkyl groups.
The term "metal" refers to alkali metals, alkaline earth metals, transition
metals or mixtures thereof.
The term "Metal to Substrate ratio" refers to the ratio of the total
equivalents of the metal to the
equivalents of the substrate. An overbased sulphonate detergent typically has
a metal ratio of 12.5:1 to
40:1, in one aspect 13.5:1 to 40:1, in another aspect 14.5:1 to 40:1, in yet
another aspect 15.5:1 to 40:1
and in yet another aspect 16.5:1 to 40:1.
Total Base Number (TBN or BN) numbers reflect more alkaline products and
therefore a greater
alkalinity reserve. The TBN of a sample can be determined by ASTM Test No.
D2896 or any other
equivalent procedure. In general terms, TBN is the neutralization capacity of
one gram of the
lubricating composition expressed as a number equal to the mg of potassium
hydroxide providing the
equivalent neutralization. Thus, a TBN of 10 means that one gram of the
composition has a
neutralization capacity equal to 10 mg of potassium hydroxide. TBN of the
actives should be
measured.
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The term "low overbased" or "LOB" refers to an overbased detergent having a
low TBN of the actives
of about 0 to about 60.
The term "medium overbased" or "MOB" refers to an overbased detergent having a
medium TBN of
the actives of greater than about 60 to about 200.
The term "high overbased" or "HOB" refers to an overbased detergent having a
high TBN of the
actives of greater than about 200 to about 400.
Lubricating Oil Additive Composition
The lubricating oil additive composition of the present invention comprises a
first carboxylate
detergent having a TBN of from about 60 to about 200 TBN; a second carboxylate
detergent having a
TBN of from about 200 to about 400 TBN and a polyalkenyl succinimide. Other
additives may be
employed in the lubricating oil additive composition.
Carboxylate Detergent
In one embodiment, a first carboxylate detergent and a second carboxylate
detergent are employed in
the lubricating oil additive composition.
Typically, the carboxylate detergents are prepared according methods that are
well known in the art,
including, but not limited to, the processes described in U.S. Patent
Publication No. 2007/0105730
and U.S. Patent Publication No. 2007/0027043.
In one embodiment, the first carboxylate detergent is a single-ring
carboxylate.
Single-Ring Carboxylate
One of the carboxylate detergents that may be used in the lubricating oil
additive composition is a
single-ring carboxylate having a Total Base Number (TBN) of the actives of
greater than about 60 to
about 200.
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The single carboxylate has the following structure:
2+
-Ca
_ ,=- -..,. _
..
0" 0
=o
R
wherein R is a linear hydrocarbyl group, a branched hydrocarbyl group or
mixtures thereof.
Preferably, R is a linear hydrocarbyl group. More preferably, R is an alkyl
group having from 12 to
40 carbon atoms.
The single-ring carboxylate is prepared according to the following method.
In the first step, hydrocarbyl phenols are neutralized in the presence of a
promoter. In one
embodiment, said hydrocarbyl phenols are neutralized using an alkaline earth
metal base in the
presence of at least one C1 to C4 carboxylic acid. Preferably, this reaction
is carried out in the absence
of alkali base, and in the absence of dialcohol or monoalcohol.
The hydrocarbyl phenols may contain up to 100% linear hydrocarbyl groups, up
to 100% branched
hydrocarbyl groups, or both linear and branched hydrocarbyl groups.
Preferably, the linear
hydrocarbyl group, if present, is alkyl, and the linear alkyl radical contains
12 to 40 carbon atoms,
more preferably 18 to 30 carbon atoms. The branched hydrocarbyl radical, if
present, is preferably
alkyl and contains at least nine carbon atoms, preferably 9 to 24 carbon
atoms, more preferably 10 to
15 carbon atoms. In one embodiment, the hydrocarbyl phenols contain up to 85%
of linear
hydrocarbyl phenol (preferably at least 35% linear hydrocarbyl phenol) in
mixture with at least 15%
of branched hydrocarbyl phenol.
The use of an alkylphenol containing at least 35% of long-chain linear
alkylphenol (from 18 to 30
carbon atoms) is particularly attractive because a long linear alkyl chain
promotes the compatibility
and solubility of the additives in lubricating oils. However, the presence of
relatively heavy linear
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alkyl radicals in the alkylphenols can make the latter less reactive than
branched alkylphenols, hence
the need to use harsher reaction conditions to bring about their
neutralization by an alkaline earth
metal base.
Branched alkylphenols can be obtained by reaction of phenol with a branched
olefin, generally
originating from propylene. They consist of a mixture of monosubstituted
isomers, the great majority
of the substituents being in the para position, very few being in the ortho
position, and hardly any in
the meta position. That makes them relatively more reactive towards an
alkaline earth metal base,
since the phenol function is practically devoid of steric hindrance.
On the other hand, linear alkylphenols can be obtained by reaction of phenol
with a linear olefin,
generally originating from ethylene. They consist of a mixture of
monosubstituted isomers in which
the proportion of linear alkyl substituents in the ortho, para, and metal
positions is more uniformly
distributed. This makes them less reactive towards an alkaline earth metal
base since the phenol
function is less accessible due to considerable steric hindrance, due to the
presence of closer and
generally heavier alkyl substituents. Of course, linear alkylphenols may
contain alkyl substituents
with some branching which increases the amount of para substituents and,
resultantly, increases the
relative reactivity towards alkaline earth metal bases.
The alkaline earth metal bases that can be used for carrying out this step
include the oxides or
hydroxides of calcium, magnesium, barium, or strontium, and particularly of
calcium oxide, calcium
hydroxide, magnesium oxide, and mixtures thereof. In one embodiment, slaked
lime (calcium
hydroxide) is preferred.
The promoter used in this step can be any material that enhances
neutralization. For example, the
promoter may be a polyhydric alcohol, dialcohol, monoalcohol, ethylene glycol
or any carboxylic
acid. Preferably, a carboxylic acid is used. More preferably, Ci to C4
carboxylic acids are used in this
step including, for example, formic, acetic, propionic and butyric acid, and
may be used alone or in
mixture. Preferably, a mixture of acids is used, most preferably a formic
acid/acetic acid mixture. The
molar ratio of formic acid/acetic acid should be from 0.2:1 to 100:1,
preferably between 0.5:1 and 4:1,
and most preferably 1:1. The carboxylic acids act as transfer agents,
assisting the transfer of the
alkaline earth metal bases from a mineral reagent to an organic reagent.
The neutralization operation is carried out at a temperature of at least 200
C, preferably at least
215 C, and more preferably at least 240 C. The pressure is reduced gradually
below atmospheric in
order to distill off the water of reaction. Accordingly the neutralization
should be conducted in the
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absence of any solvent that may form an azeotrope with water. Preferably, the
pressure is reduced to
no more than 7,000 Pa (70 mbars).
The quantities of reagents used should correspond to the following molar
ratios: (1) alkaline earth
metal base/hydrocarbyl phenol of 0.2:1 to 0.7:1, preferably 0.3:1 to 0.5:1;
and (2) carboxylic
acid/hydrocarbyl phenol of 0.01:1 to 0.5:1, preferably from 0.03:1 to 0.15:1.
Preferably, at the end of this neutralization step the hydrocarbyl phenate
obtained is kept for a period
not exceeding fifteen hours at a temperature of at least 215 C and at an
absolute pressure of between
5,000 and 10<sup>5</sup> Pa (between 0.05 and 1.0 bar). More preferably, at the end
of this neutralization
step the hydrocarbyl phenate obtained is kept for between two and six hours at
an absolute pressure of
between 10,000 and 20,000 Pa (between 0.1 and 0.2 bar).
By providing that operations are carried out at a sufficiently high
temperature and that the pressure in
the reactor is reduced gradually below atmospheric, the neutralization
reaction is carried out without
the need to add a solvent that forms an azeotrope with the water formed during
this reaction.
B. Carboxylation Step
The carboxylation step is conducted by simply bubbling carbon dioxide into the
reaction medium
originating from the preceding neutralization step and is continued until at
least 20 mole % of the
starting hydrocarbyl phenols is converted to hydrocarbyl salicylate (measured
as salicylic acid by
potentiometric determination). It must take place under pressure in order to
avoid any decarboxylation
of the alkylsalicylate that forms.
Preferably, at least 22 mole % of the starting hydrocarbyl phenols is
converted to hydrocarbyl
salicylate using carbon dioxide at a temperature of between 180 C and 240 C,
under a pressure within
the range of from above atmospheric pressure to 15x105 Pa (15 bars) for a
period of one to eight
hours.
According to one variant, at least 25 mole % of the starting hydrocarbyl
phenols is converted to
hydrocarbyl salicylate using carbon dioxide at a temperature equal to or
greater than 200 C under a
pressure of 4x105 Pa (4 bars).
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C. Filtration Step
The product of the carboxylation step may advantageously be filtered. The
purpose of the filtration
step is to remove sediments, and particularly crystalline calcium carbonate,
which might have been
formed during the preceding steps, and which may cause plugging of filters
installed in lubricating oil
circuits.
D. Separation Step
At least 10% of the starting hydrocarbyl phenol is separated from the product
of the carboxylation
step. Preferably, the separation is accomplished using distillation. More
preferably, the distillation is
carried out in a wiped film evaporator at a temperature of from about 150 C to
about 250 C and at a
pressure of about 0.1 to about 4 mbar; more preferably from about 190 C to
about 230 C and at about
0.5 to about 3 mbar; most preferably from about 195 C to about 225 C and at a
pressure of about 1 to
about 2 mbar. At least 10% of the starting hydrocarbyl phenol is separated.
More preferably, at least
30% of the starting hydrocarbyl phenol is separated. Most preferably, up to
55% of the starting
hydrocarbyl phenol is separated. The separated hydrocarbyl phenol may then be
recycled to be used
as starting materials in the novel process or in any other process.
Unsulfurized, Carboxylate-Containing Additive
The unsulfurized, carboxylate-containing additive formed by the present
process can be characterized
by its unique composition, with much more alkaline earth metal single-aromatic-
ring hydrocarbyl
salicylate and less hydrocarbyl phenol than produced by other routes. When the
hydrocarbyl group is
an alkyl group, the unsulfurized, carboxylate-containing additive has the
following composition; (a)
less than 40% alkylphenol, (b) from 10% to 50% alkaline earth metal
alkylphenate, and (b) from 15%
to 60% alkaline earth metal single-aromatic-ring alkylsalicylate.
Unlike alkaline earth metal alkylsalicylates produced by other process, this
unsulfurized, carboxylate-
containing additive composition can be characterized by having only minor
amounts of an alkaline
earth metal double-aromatic-ring alkylsalicylates. The mole ratio of single-
aromatic-ring
alkylsalicylate to double-aromatic-ring alkylsalicylate is at least 8:1.
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Characterization of the Product by Infrared Spectrometry
Out-of-aromatic-ring-plane C--H bending vibrations were used to characterize
the unsulfurized
carboxylate-containing additive of the present invention. Infrared spectra of
aromatic rings show
strong out-of-plane C--H bending transmittance band in the 675-870 cm-1
region, the exact frequency
depending upon the number and location of substituents. For ortho-
disubstituted compounds,
transmittance band occurs at 735-770 cm-1. For para-disubstituted compounds,
transmittance band
occurs at 810-840 cm-1.
Infrared spectra of reference chemical structures relevant to the present
invention indicate that the out-
of-plane C--H bending transmittance band occurs at 750 3 cm-1 for ortho-
alkylphenols, at 760 2 cm-1
for salicylic acid, and at 832 3 cm-1 for para-alkylphenols.
Alkaline earth alkylphenates known in the art have infrared out-of-plane C--H
bending transmittance
bands at 750 3 cm-1 and at 832 3 cm-1. Alkaline earth alkylsalicylates known
in the art have infrared
out-of-plane C--H bending transmittance bands at 763 3 cm-land at 832 3 cm-1.
The unsulfurized carboxylate-containing additive of the present invention
shows essentially no out-of-
plane C--H bending vibration at 763 3 cm-1, even though there is other
evidence that alkylsalicylate is
present. This particular characteristic has not been fully explained. However,
it may be hypothesized
that the particular structure of the single aromatic ring alkylsalicylate
prevents in some way this out-
of-plane C--H bending vibration. In this structure, the carboxylic acid
function is engaged in a cyclic
structure, and thus may generate increased steric hindrance in the vicinity of
the aromatic ring,
limiting the free motion of the neighbor hydrogen atom. This hypothesis is
supported by the fact that
the infrared spectrum of the acidified product (in which the carboxylic acid
function is no longer
engaged in a cyclic structure and thus can rotate) has an out-of-plane C--H
transmittance band at
763 3 cm-1.
The unsulfurized carboxylate-containing additive of the present invention can
thus be characterized
by having a ratio of infrared transmittance band of out-of-plane C--H bending
at about 763 3 cm-ito
out-of-plane C--H bending at 832 3 cm-lof less than 0.1:1.
The unsulfurized, carboxylate-containing additive formed by this method, being
non-sulfurized,
would provide improved high temperature deposit control performance over
sulfurized products.
Being alkali-metal free, this additive can be employed as a detergent-
dispersant in applications, such
as marine engine oils, where the presence of alkali metals have proven to have
harmful effects.
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Additional Carboxylate Additives
The second carboxlyate detergent may be prepared according the following
process.
The overbased alkaline earth metal alkylhydroxybenzoate (i.e., carboxylate
detergent) of the present
invention will typically have a structure as shown below as Formula (I).
OH OH
0
1 _c_0
_m_0
_c11_
R R
wherein R is a linear aliphatic group, branched aliphatic group or a mixture
of linear and branched
aliphatic groups. Preferably, R is an alkyl or alkenyl group. More preferably,
R is an alkyl group.
M is an alkaline earth metal selected of the group consisting of calcium,
barium, magnesium,
strontium. Calcium and magnesium are the preferred alkaline earth metal.
Calcium is more preferred.
When R is a linear aliphatic group, the linear alkyl group typically comprises
from about 12 to 40
carbon atoms, more preferably from about 18 to 30 carbon atoms.
When R is a branched aliphatic group, the branched alkyl group typically
comprises at least 9 carbon
atoms, preferably from about 9 to 40 carbon atoms, more preferably from about
9 to 24 carbon atoms
and most preferably from about 10 to 18 carbon atoms. Such branched aliphatic
groups are preferably
derived from an oligomer of propylene or butene.
R can also represent a mixture of linear or branched aliphatic groups.
Preferably, R represents a
mixture of linear alkyl containing from about 20 to 30 carbon atoms and
branched alkyl containing
about 12 carbon atoms.
When R represents a mixture of aliphatic groups, the alkaline-earth metal
alkylhydroxybenzoic acid
employed in the present invention may contain a mixture of linear groups, a
mixture of branched
groups, or a mixture of linear and branched groups. Thus, R can be a mixture
of linear aliphatic
groups, preferably alkyl; for example, an alkyl group selected from the group
consisting of C14-C16,
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C16-C18, C18-C20, C20-C22, C20-C24 and C20-C28 alkyl and mixtures thereof and
derived from normal
alpha olefins. Advantageously, these mixtures include at least 95 mole %,
preferably 98 mole % of
alkyl groups and originating from the polymerization of ethylene.
The alkaline earth metal alkylhydroxybenzoates (i.e., carboxylates) of the
present invention wherein R
represents a mixture of alkyl groups, can be prepared from linear alpha olefin
cuts, such as those
marketed by Chevron Phillips Chemical Company under the names Normal Alpha
Olefin C26-C28 or
Normal Alpha Olefin C20-C24, by British Petroleum under the name C20-C26
Olefin, by Shell Chimie
under the name SHOP C20-C22, or mixtures of these cuts or olefins from these
companies having
from about 20 to 28 carbon atoms.
The --COOM group of Formula (I) can be in the ortho, meta or para position
with respect to the
hydroxyl group.
The alkaline earth metal alkylhydroxybenzoates of the present invention can be
any mixture of
alkaline-earth metal alkylhydroxybenzoic acid having the --COOM group in the
ortho, meta or para
position.
The alkaline earth metal alkylhydroxybenzoates of the present invention are
generally soluble in oil as
characterized by the following test.
A mixture of a 600 Neutral diluent oil and the alkylhydroxybenzoate at a
content of 10 wt % with
respect to the total weight of the mixture is centrifuged at a temperature of
60 C and for 30 minutes,
the centrifugation being carried out under the conditions stipulated by the
standard ASTM D2273 (it
should be noted that centrifugation is carried out without dilution, i.e.
without adding solvent);
immediately after centrifugation, the volume of the deposit which forms is
determined; if the deposit
is less than 0.05% v/v (volume of the deposit with respect to the volume of
the mixture), the product
is considered as soluble in oil.
Advantageously, the TBN of the high overbased alkaline earth metal
alkylhydroxybenzoate of the
present invention is greater than 250, preferably from about 250 to 450 and
more preferably from
about 300 to 400 and will generally have less than 3 volume %, preferably less
than 2 volume % and
more preferably less than 1 volume % crude sediment. For the middle overbased
alkaline earth metal
alkylhydroxybenzoate of the present invention, the TBN is from about 100 to
250, preferably from
about 140 to 230 and will generally have less than 1 volume %, preferably less
than 0.5 volume %
crude sediment.
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Process
In the first embodiment of the present invention, the process for preparing
the overbased alkaline
earth metal alkylhydroxybenzoate involves overbasing the alkaline earth metal
alkylhydroxylbenzoate
or a mixture of alkaline earth metal alkylhydroxylbenzoate and up to 50 mole %
of alkylphenol, based
on the total mixture of alkylhydroxybenzoate and alkylphenol, with a molar
excess of alkaline earth
metal base and at least one acidic overbasing material in presence of at least
one carboxylic acid
having from one to four carbon atoms and a solvent selected form the group
consisting of aromatic
hydrocarbons, aliphatic hydrocarbons, monoalcohols, and mixtures thereof.
Overbasing of the alkaline earth metal alkylhydroxybenzoate or mixture of
alkaline earth metal
alkylhydroxybenzoate and alkylphenol may be carried out by any method known by
a person skilled
in the art to produce overbased alkaline earth metal alkylhydroxybenzoates.
However, it has been
surprisingly discovered that the addition of a small quantity of C1-C4
carboxylic acid at this step
decreases the crude sediment obtained at the end of overbasing step by a
factor of at least 3.
The C1-C4 carboxylic acids used in the neutralization step include formic
acid, acetic acid, propionic
acid, and butyric acid, which may be used alone or in mixture. It is
preferable to use mixtures of such
acids as, for example, formic acid:acetic acid, in a molar ratio of formic
acid:acetic acid of from about
0.1:1 to 100:1, preferably from about 0.5:1 to 4:1, more preferably from about
0.5:1 to 2:1, and most
preferably about 1:1.
Generally, the overbasing reaction is carried out in a reactor in the presence
of alkylhydroxybenzoic
acid from about 10 wt % to 70 wt %, alkylphenol from about 1 wt % to 30 wt %,
diluent oil from
about 0 wt % to 40 wt %, an aromatic solvent from about 20 wt % to 60 wt %.
The reaction mixture is
agitated. The alkaline earth metal associated with an aromatic solvent, a
monoalcohol and carbon
dioxide are added to the reaction while maintaining the temperature between
about 20 C and 80 C.
The degree of overbasing may be controlled by the quantity of the alkaline
earth metal, carbon
dioxide and the reactants added to the reaction mixture and the reaction
conditions used during the
carbonation process.
The weight ratios of reagents used (methanol, xylene, slaked lime and CO2)
will correspond to the
following weight ratios: Xylene:slaked lime from about 1.5:1 to 7:1,
preferably from about 2:1 to 4:1.
Methanol:slaked lime from about 0.25:1 to 4:1, preferably from about 0.4:1 to
1.2:1. Carbon
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dioxide:slaked lime from a molar ratio about 0.5:1 to 1.3:1, preferably from
about 0.7:1 to 1.0:1. Ci-
C4 carboxylic acid:alkylhydroxybenzoic acid a molar ratio from about 0.02:1 to
1.5:1, preferably from
about 0.1:1 to 0.7:1.
Lime is added as a slurry, i.e., as a pre-mixture of lime, methanol, xylene,
and CO<sub>2</sub> is introduced
over a period of 1 hour to 4 hours, at a temperature between about 20 C and 65
C.
The quantity of lime and CO<sub>2</sub> are adjusted in order to obtain a high
overbased material
(TBN>250) and crude sediment in the range of 0.4 to 3 volume %, preferably in
the range of 0.6 to
1.8 volume %, without any deterioration of the performance. With the omission
of C1-C4 carboxylic
acid, it is not able to reach this low level of crude sediment. Typically,
crude sediment without a C1-
C4 carboxylic acid will range from about 4 to 8 volume %.
For a middle overbased material (TBN from about 100 to 250), the quantity of
lime and CO2 are
adjusted in order to obtain a crude sediment in the range of 0.2 to 1 volume
%. The crude sediment
without the use of C1-C4 carboxylic acid will range from about 0.8 to 3 volume
%.
In a second embodiment of the present invention, the overbased alkaline earth
metal
alkylhydroxybenzoate may be prepared by the following steps:
A. Formation of the Alkali Metal Base Alkylphenate:
In the first step, alkylphenols are neutralized using an alkali metal base
preferably in the presence of a
light solvent, such as toluene, xylene isomers, light alkylbenzene or the
like, to form the alkali metal
base alkylphenate. In one embodiment, the solvent forms an azeotrope with
water. In another
embodiment, the solvent may also be a mono-alcohol such as 2-ethylhexanol. In
this case, the 2-
ethylhexanol is eliminated by distillation before carboxylation. The objective
with the solvent is to
facilitate the elimination of water.
The hydrocarbyl phenols may contain up to 100 wt % linear hydrocarbyl groups,
up to 100 wt %
branched hydrocarbyl groups, or both linear and branched hydrocarbyl groups.
Preferably, the linear
hydrocarbyl group, if present, is alkyl, and the linear alkyl group contains
from about 12 to 40 carbon
atoms, more preferably from about 18 to 30 carbon atoms. The branched
hydrocarbyl group, if
present, is preferably alkyl and contains at least 9 carbon atoms, preferably
from about 9 to 40 carbon
atoms, more preferably from about 9 to 24 carbon atoms and most preferably
from about 10 to 18
carbon atoms. In one embodiment, the hydrocarbyl phenols contain up to 85 wt %
of linear
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hydrocarbyl phenol (preferably at least 35 wt % linear hydrocarbyl phenol) in
mixture with at least 15
wt % of branched hydrocarbyl phenol. In one embodiment, the hydrocarbyl
phenols are 100% linear
alkylphenols.
The use of an alkylphenol containing up to at least 35 wt % of long linear
alkylphenol (from about 18
to 30 carbon atoms) is particularly attractive because a long linear alkyl
chain promotes the
compatibility and solubility of the additives in lubricating oils.
Branched alkylphenols can be obtained by reaction of phenol with a branched
olefin, generally
originating from propylene.
They consist of a mixture of monosubstituted isomers, the great majority of
the substituents being in
the para position, very few being in the ortho position, and hardly any in the
meta position.
On the other hand, linear alkylphenols can be obtained by reaction of phenol
with a linear olefin,
generally originating from ethylene. They consist of a mixture of
monosubstituted isomers in which
the proportion of linear alkyl substituents in the ortho, meta, and para
positions is much more
uniformly distributed. Of course, linear alkylphenols may contain alkyl
substituents with some
branching which increases the amount of para substituents and, resultantly may
increase the relative
reactivity towards alkali metal bases.
The alkali metal bases that can be used for carrying out this step include the
oxides or hydroxides of
lithium, sodium or potassium. In a preferred embodiment, potassium hydroxide
is preferred. In
another preferred embodiment, sodium hydroxide is preferred.
An objective of this step is to have an alkylphenate having less than 2000
ppm, preferably less than
1000 ppm and more preferably less than 500 ppm of water.
In this regard, the first step is carried out at a temperature high enough to
eliminate water. In one
embodiment, the product is put under a slight vacuum in order to require a
lower reaction
temperature.
In one embodiment, xylene is used as a solvent and the reaction conducted at a
temperature between
130 C and 155 C, under an absolute pressure of 800 mbar (8x104 Pa).
In another embodiment, 2-ethylhexanol is used as solvent. As the boiling point
of 2-ethylhexanol
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(184 C) is significantly higher than xylene (140 C), the reaction is conducted
at a temperature of at
least 150 C.
The pressure is reduced gradually below atmospheric in order to complete the
distillation of water
reaction. Preferably, the pressure is reduced to no more than 70 mbar (7x103
Pa).
By providing that operations are carried out at a sufficiently high
temperature and that the pressure in
the reactor is reduced gradually below atmospheric, the formation of the
alkali metal base
alkylphenate is carried out without the need to add a solvent and forms an
azeotrope with the water
formed during this reaction. For instance, temperature is heated up to 200 C
and then the pressure is
reduced gradually below atmospheric. Preferably the pressure is reduced to no
more than 70 mbar
(7x103 Pa).
Elimination of water is done over a period of at least 1 hour, preferably at
least 3 hours.
The quantities of reagents used should correspond to the following molar
ratios: alkali metal
base:alkylphenol from about 0.5:1 to 1.2:1, preferably from about: 0.9:1 to
1.05:1 solvent:alkylphenol
(wt:wt) from about 0.1:1 to 5:1, preferably from about 0.3:1 to 3:1
B. Carboxylation:
This carboxylation step is conducted by simply bubbling carbon dioxide (CO2)
into the reaction
medium originating from the preceding neutralization step and is continued
until at least 50 mole % of
the starting alkylphenol has been converted to alkylhydroxybenzoic acid
(measured as
hydroxybenzoic acid by potentiometric determination).
At least 50 mole %, preferably 75 mole %, and more preferably 85 mole %, of
the starting
alkylphenol is converted to alkylhydroxylbenzoate using carbon dioxide at a
temperature between
about 110 C and 200 C under a pressure within the range of from about
atmospheric to 15 bar
(15x105 Pa), preferably from 1 bar (1x105 Pa) to 5 bar (5x105 Pa), for a
period between about 1 and 8
hours.
In one variant with potassium salt, temperature is preferably between about
125 C and 165 C and
more preferably between 130 C and 155 C, and the pressure is from about
atmospheric to 15 bar
(15x105 Pa), preferably from about atmospheric to 4 bar (4x105 Pa).
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In another variant with sodium salt, temperature is directionally lower
preferably between from about
110 C and 155 C. More preferably from about 120 C and 140 C and the pressure
from about 1 bar to
20 bar (1x105 to 20x105 Pa), preferably from 3 bar to 15 bar (3x105 to 15x105
Pa).
The carboxylation is usually carried out, diluted in a solvent such as
hydrocarbons or alkylate, e.g.,
benzene, toluene, xylene and the like. In this case, the weight ratio of
solvent:hydroxybenzoate is
from about 0.1:1 to 5:1, preferably from about 0.3:1 to 3:1.
In another variant, no solvent is used. In this case, carboxylation is
conducted in the presence of
diluent oil in order to avoid a too viscous material.
The weight ratio of diluent oil:alkylhydroxybenzoate is form about 0.1:1 to
2:1, preferably from about
0.2:1 to 1:1, and more preferably from about 0.2:1 to 0.5:1.
C. Acidification:
The objective of this step is to acidify the alkylhydroxybenzoate salt diluted
in the solvent to give an
alkylhydroxybenzoic acid. Any acid stronger than alkylhydroxybenzoic acid
could be utilized.
Usually hydrochloric acid or aqueous sulfuric acid is utilized.
Acidification step is conducted with an H equivalent excess of acid versus
potassium hydroxide of at
least 5 H+ equivalent %, preferably 10 H+ equivalent % and more preferably 20
H+ equivalent %, the
acidification is complete.
In one embodiment, sulfuric acid is used. It is diluted to about 5 volume % to
50 volume %,
preferably 10 volume % to 30 volume %. The quantity of sulfuric acid used
versus hydroxybenzoate
(salicylate), on a per mole of hydroxybenzoate basis, is at least 0.525 mole,
preferably 0.55 mole and
more preferably 0.6 mole of sulfuric acid.
The acidification reaction is carried out under agitation or with any suitable
mixing system at a
temperature from about room temperature to 95 C, preferably from about 50 C to
70 C, over a period
linked with the efficiency of the mixing. For example, when a stirred reactor
is utilized and the period
is from about 15 minutes to 300 minutes, preferably from about 60 minutes to
180 minutes. When a
static mixer is utilized, the period may be shorter.
At the end of this period time, the agitation is stopped in order to allow
good phase separation before
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the aqueous phase was separated. After phase separation is complete, the
organic phase is then
neutralized, overbased, centrifugated to eliminate impurities and distilled to
eliminate solvent. The
water phase is treated as a waste material. In one embodiment, the organic
phase is sent through a
coalescer to decrease the level of residual water and water-soluble impurities
such as sulfuric acid and
potassium sulfate as a consequence.
D. Contact with Carboxylic Acid:
The alkylhydroxybenzoic acid in step C is contacted with at least one
carboxylic acid having from
about one to four carbon atoms.
E. Neutralization:
The mixture of alkylhydroxybenzoic acid and the at least one carboxylic acid
from step D is
neutralized with an alkaline earth metal base and at least one solvent
selected from the group
consisting of aromatic hydrocarbons, aliphatic hydrocarbons monoalcohols, and
mixtures thereof to
form an alkaline earth metal alkylhydroxylbenzoate and at least one alkaline
earth metal carboxylic
acid salt.
F. Overbasing:
Overbasing of the mixture of alkylhydroxybenzoic acid and alkylphenol may be
carried out by any
method known by a person skilled in the art to produce alkylhydroxybenzoates.
However, it has been
surprisingly discovered that the addition of a small quantity of C1-C4
carboxylic acid at this step
decreases the crude sediment obtained at the end of overbasing step by a
factor of at least 3.
The C1-C4 carboxylic acids used in the neutralization step include formic
acid, acetic acid, propionic
acid, and butyric acid, which may be used alone or in mixture. It is
preferable to use mixtures of such
acids as, for example, formic acid:acetic acid, in a molar ratio of formic
acid:acetic acid of from about
0.1:1 to 100:1, preferably from about 0.5:1 to 4:1, and more preferably from
about 0.5:1 to 2:1.
Generally, the overbasing reaction is carried out in a reactor in the presence
of alkylhydroxybenzoic
acid from about 10 wt % to 70 wt %, alkylphenol from about 1 wt % to 30 wt %,
diluent oil from
about 0 wt % to 40 wt %, an aromatic solvent from about 20 wt % to 60 wt %.
The reaction mixture is
agitated. The alkaline earth metal associated with an aromatic solvent, a
monoalcohol and carbon
dioxide are added to the reaction while maintaining the temperature between
about 20 C and 80 C.
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The degree of overbasing may be controlled by the quantity of the alkaline
earth metal, carbon
dioxide and the reactants added to the reaction mixture and the reaction
conditions used during the
carbonation process.
The weight ratios of reagents used (methanol, xylene, slaked. lime and CO2)
will correspond to the
following weight ratios: Xylene:slaked lime from about 1.5:1 to 7:1,
preferably from about 2:1 to 4:1.
Methanol:slaked lime from about 0.25:1 to 4:1, preferably from about 0.4:1 to
1.2:1. Carbon
dioxide:slaked lime from a molar ratio about 0.5:1 to 1.3:1, preferably from
about 0.7:1 to 1.0:1. C1-
C4 carboxylic acid:alkylhydroxybenzoic acid a molar ratio from about 0.02:1 to
1.5:1, preferably from
about 0.1:1 to 0.7:1.
Lime is added as a slurry, i.e., as a pre-mixture of lime, methanol, xylene,
and CO2 is introduced over
a period of 1 hour to 4 hours, at a temperature between about 20 C and 65 C.
The quantity of lime and CO2 are adjusted in order to obtain a high overbased
material (TBN >250)
and crude sediment in the range of 0.4 to 3 volume %, preferably in the range
of 0.6 to 1.8 volume %,
without any deterioration of the performance. With the omission of C1-C4
carboxylic acid, it is not
able to reach this low level of crude sediment. Typically, crude sediment
without a C1-C4 carboxylic
acid will range from about 4 to 8 volume %.
For a middle overbased material (TBN from about 100 to 250), the quantity of
lime and CO2 are
adjusted in order to obtain a crude sediment in the range of 0.2 to 1 volume
%. The crude sediment
without the use of C1-C4 carboxylic acid will range from about 0.8 to 3 volume
%.
In the third embodiment of the present invention, the overbased alkaline earth
metal
alkylhydroxybenzoate may be obtained by a process having steps A through C
above followed by:
D. Neutralization:
The mixture of alkylhydroxybenzoic acid from step C is neutralized with a
molar excess of an
alkaline earth metal base and at least one solvent selected from the group
consisting of aromatic
hydrocarbons, aliphatic hydrocarbons, monoalcohols, and mixtures thereof to
form an alkaline earth
metal alkylhydroxybenzoate.
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E. Contact with Carboxylic Acid:
The alkaline earth metal alkylhydroxybenzoate and alkaline earth metal base
formed in step D is
contacted with at least one carboxylic acid having from about one to four
carbon atoms to form a
mixture of alkaline earth metal alkylhydroxybenzoate and at least one alkaline
earth metal
carboxylate.
F. Overbasing:
The alkaline earth metal alkylhydroxybenzoate is then overbased according to
the description
provided above.
Optionally, predistillation, centrifugation and distillation may also be
utilized to remove solvent and
crude sediment. Water, methanol and a portion of the xylene may be eliminated
by heating between
about 110 C to 134 C. This may be followed by centrifugation to eliminated
unreacted lime. Finally,
xylene may be eliminated by heating under vacuum in order to reach a flash
point of at least about
160 C as determined with the Pensky-Martens Closed Cup (PMCC) Tester described
in ASTM D93.
In one embodiment, the lubricating oil additive composition comprises at least
one polyalkenyl
succinimide that is prepared according the process described in U.S. Patent
No. 5,821,905, U.S.
Patent No. 5,334,321 and U.S. Patent No.,5,356,552 which are herein
incorporated by reference and
by other methods that are well known in the art.
The lubricating oil additive composition may also comprise other additives
described below. These
additional components can be blended in any order and can be blended as
combinations of
components.
Other Additive Components
The following additive components are examples of some of the components that
may employed in
the present invention. These examples of additives are provided to illustrate
the present invention, but
they are not intended to limit it:
A. Metal Detergents
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Sulfurized or unsulfurized alkyl or alkenyl phenates, sulfonates derived from
synthetic or natural
feedstocks, carboxylates, salicylates, phenalates, sulfurized or unsulfurized
metal salts of multi-
hydroxy alkyl or alkenyl aromatic compounds, alkyl or alkenyl hydroxy aromatic
sulfonates,
sulfurized or unsulfurized alkyl or alkenyl naphthenates, metal salts of
alkanoic, acids, metal salts of
an alkyl or alkenyl multiacid, and chemical and physical mixtures thereof.
B. Anti-Oxidants
Anti-oxidants reduce the tendency of mineral oils to deteriorate in service
which deterioration is
evidenced by the products of oxidation such as sludge and varnish-like
deposits on the metal surfaces
and by an increase in viscosity. Antioxidants may include, but are not limited
to, such anti-oxidants as
phenol type (phenolic) oxidation inhibitors, such as 4,4'-methylene-bis(2,6-di-
tert-butylphenol), 4,4'-
bis(2,6-di-tert-butylphenol), 4,4'-bis(2-methyl-6-tert-butylphenol), 2,2'-
methylene-bis(4-methy1-6-tert-
butylphenol), 4,4'-butyldene-bis(3-methy1-6-tert-butyl phenol), 4,4'-
isopropylidene-bis(2,6-di-tert-
bulylphenol), 2,2'-methylene-bis(4-methyl-6-nonylphenol), 2,2'-isobutylidene-
bis(4,6-
dimethylphenol), 2,2'-methylene-bis(4-methyl-6-cyclohexylphenol), 2,6-di-tert-
buty1-1-4-
methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethy1-6-tert-butyl-
phenol, 2,6-di-tert-
dimethylamino-p-cresol, 2,6-di-tert-4-(N,N'-dimethylaminomethylphenol), 4,4'-
thiobis(2-methy1-6-
tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), bis(3-methy1-4-
hydroxy-5-tert-
butylbenzy1)-sulfide, and bis(3,5-di-tert-buty1-4-hydroxybenzyl).
Diphenylamine-type oxidation
inhibitors include, but are not limited to, alkylated diphenylamine, phenyl-
.alpha.-naphthylamine, and
alkylated-.alpha.-naphthylamine. Other types of oxidation inhibitors include
metal dithiocarbamate
(e.g., zinc dithiocarbamate), and methylenebis(dibutyidithiocarbamate). The
anti-oxidant is generally
incorporated into an oil in an amount of about 0 to about 10 wt %, preferably
0.05 to about 3.0 wt %,
per total amount of the engine oil.
C. Anti-Wear/Extreme Pressure Agents
As their name implies, these agents reduce wear of moving metallic parts.
Examples of such agents
include, but are not limited to, phosphates, phosphites, carbamates, esters,
sulfur containing
compounds, molybdenum complexes, zinc dialkyldithiophosphate (primary alkyl,
secondary alkyl,
and aryl type), sulfurized oils, sulfurized isobutylene, sulfurized
polybutene, diphenyl sulfide, methyl
trichlorostearate, chlorinated naphthalene, fluoroalkylpolysiloxane, and lead
naphthenate.
D. Rust Inhibitors (Anti-rust Agents)
1) Nonionic polyoxyethylene surface active agents: polyoxyethylene lauryl
ether,
polyoxyethylene higher alcohol ether, polyoxyethylene nonyl phenyl ether,
polyoxyethylene
octyl phenyl ether, polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl
ether,
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polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol monooleate,
and
polyethylene glycol monooleate.
2) Other compounds: stearic acid and other fatty acids, dicarboxylic acids,
metal soaps, fatty
acid amine salts, metal salts of heavy sulfonic acid, partial carboxylic acid
ester of polyhydric
alcohol, and phosphoric ester.
E. Demulsifiers
Addition product of alkylphenol and ethylene oxide, polyoxyethylene alkyl
ether, and
polyoxyethylene sorbitan ester.
F. Friction Modifiers
Fatty alcohols, 1,2-diols, borated 1,2-diols, fatty acids, amines, fatty acid
amides, borated esters, and
other esters.
G. Multifunctional Additives
Sulfurized oxymolybdenum dithiocarbamate, sulfurized oxymolybdenum organo
phosphorodithioate,
oxymolybdenum monoglyceride, oxymolybdenum diethylate amide, amine-molybdenum
complex
compound, and sulfur-containing molybdenum complex compound.
H. Viscosity Index Improvers or Thickeners
Polymethacrylate type polymers, ethylene-propylene copolymers, styrene-
isoprene copolymers,
hydrogenated styrene-isoprene copolymers, polyisobutylene, and dispersant type
viscosity index
improvers.
I. Pour Point Depressants
Polymethyl methacrylate.
J. Foam Inhibitors
Alkyl methacrylate polymers and dimethyl silicone polymers.
K. Metal Deactivators
Disalicylidene propylenediamine, triazole derivatives, mercaptobenzothiazoles,
thiadiazole
derivatives, and mercaptobenzimidazoles.
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L. Dispersants
Alkenyl succinimides, alkenyl succinimides modified with other organic
compounds, alkenyl
succinimides modified by post-treatment with ethylene carbonate or boric acid,
esters of polyalcohols
and polyisobutenyl succinic anhydride, phenate-salicylates and their post-
treated analogs, alkali metal
or mixed alkali metal, alkaline earth metal borates, dispersions of hydrated
alkali metal borates,
dispersions of alkaline-earth metal borates, polyamide ashless dispersants and
the like or mixtures of
such dispersants. Preferably, the alkenyl succinimide is a polyalkenyl
succinimide. More preferably,
a polyisobutenyl succinimide, wherein the polyisobutentyl group has a
molecular weight of from
about 1000 to about 2300. The alkenyl succinimide is prepared according
methods that are well
known in the art.
Lubricating Oil Composition
In one embodiment, the invention is directed to a lubricating oil composition
comprising the
lubricating oil additive composition that was described herein above and an
oil of lubricating
viscosity.
Oil of Lubricating Viscosity
The lubricating oil additive composition described above is generally added to
a base oil that is
sufficient to lubricate moving parts, for example internal combustion engines,
gears, and
transmissions. Typically, the lubricating oil composition of the present
invention comprises a major
amount of an oil of lubricating viscosity and a minor amount of the
lubricating oil additive
composition.
The base oil employed may be any of a wide variety of oils of lubricating
viscosity. The base oil of
lubricating viscosity used in such compositions may be mineral oils or
synthetic oils. A base oil
having a viscosity of at least 2.5 cSt at 40 C and a pour point below 20 C,
preferably at or below 0 C,
is desirable. The base oils may be derived from synthetic or natural sources.
Mineral oils for use as the base oil in this invention include, for example,
paraffinic, naphthenic and
other oils that are ordinarily used in lubricating oil compositions. Synthetic
oils include, for example,
both hydrocarbon synthetic oils and synthetic esters and mixtures thereof
having the desired viscosity.
Hydrocarbon synthetic oils may include, for example, oils prepared from the
polymerization of
ethylene, polyalphaolefin or PAO oils, or oils prepared from hydrocarbon
synthesis procedures using
carbon monoxide and hydrogen gases such as in a Fisher-Tropsch process. Useful
synthetic
hydrocarbon oils include liquid polymers of alpha olefins having the proper
viscosity. Especially
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useful are the hydrogenated liquid oligomers of C6 to C12 alpha olefins such
as 1-decene trimer.
Likewise, alkyl benzenes of proper viscosity, such as didodecyl benzene, can
be used. Useful
synthetic esters include the esters of monocarboxylic acids and polycarboxylic
acids, as well as mono-
hydroxy alkanols and polyols. Typical examples are didodecyl adipate,
pentaerythritol tetracaproate,
di-2-ethylhexyl adipate, dilaurylsebacate, and the like. Complex esters
prepared from mixtures of
mono and dicarboxylic acids and mono and dihydroxy alkanols can also be used.
Blends of mineral
oils with synthetic oils are also useful.
Thus, the base oil can be a refined paraffin type base oil, a refined
naphthenic base oil, or a synthetic
hydrocarbon or non-hydrocarbon oil of lubricating viscosity. The base oil can
also be a mixture of
mineral and synthetic oils.
Additive Packages
In another embodiment, the invention is directed to additive concentrates for
engine oils that contain
a first carboxylate detergent, a second carboxylate detergent and a
polyalkenyl succnimide. In
another embodiment, the invention is directed to additive concentrates for
engine oils that contain a
first carboxylate detergent having a TBN of from about 60 to about 200 TBN, a
second carboxylate
detergent having a TBN of from about 200 to about 400 TBN, and a polyalkenyl
succinimide. The
lubricating oil additive composition, which is described herein above,
concentrate may be provided as
an additive package or concentrate which will be incorporated into a
substantially inert, normally
liquid organic diluent such as, for example, mineral oil, naphtha, benzene,
toluene or xylene to form
an additive concentrate. These concentrates usually contain from about 1% to
about 99% by weight,
and in one embodiment about 10% to about 90% by weight of such diluent.
Typically, a neutral oil
having a viscosity of about 4 to about 8.5 cSt at 100 C. and preferably about
4 to about 6 cSt at
100 C. will be used as the diluent, though synthetic oils, as well as other
organic liquids which are
compatible with the additives and finished lubricating oil can also be used.
One embodiment of the invention is directed to a method for operating a diesel
locomotive engine
comprising lubricating a diesel locomotive engine with a lubricating oil
composition comprising a
major amount of an oil of lubricating viscosity and the lubricating oil
additive package described
hereinabove, which contains a first carboxylate detergent, a second
carboxylate detergent and a
polyalkenyl succnimide.
One embodiment of the invention is directed to a method for operating an
inland marine engine
comprising lubricating an inland marine engine with a lubricating oil
composition comprising a major
amount of an oil of lubricating viscosity and the lubricating oil additive
package described
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hereinabove which contains a first carboxylate detergent, a second carboxylate
detergent and a
polyalkenyl succnimide.
One embodiment of the invention is directed to a method of improving TBN
retention wherein the
lubricating oil composition comprises a major amount of an oil of lubricating
viscosity and the
lubricating oil additive package described hereinabove which contains a first
carboxylate detergent, a
second carboxylate detergent and a polyalkenyl succnimide.
Examples
Base Lubricating Oil Composition
A lubricating oil composition was prepared by blending a polyisobutenyl
succinimide, wherein the
polyisobutenyl group has a molecular weight of 2300, a 263 TBN oil concentrate
of a phenate
detergent, a 114 TBN oil concentrate of a phenate detergent, a calcium salt of
a Mannich base
alkylphenol, at least one antioxidant, a foam inhibitor, and a Group I base
oil.
Comparative Examples 1-8 were comprised primarily of the Base Lubricating Oil
Composition (see
Table 1). Examples 1-7 (Examples of the Invention) comprised the Base
Lubricating Oil
Composition and at least two carboxylate detergents ¨a 350 TBN oil concentrate
of a carboxylate
detergent and a 150 TBN oil concentrate of a carboxylate detergent (See Table
2).
Each of the comparative oils was tested in the B2-7 which is otherwise known
as the Union Pacific
Oxidation Test. This test method is described below.
30
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B2-7 Test/ Union Pacific Oxidation Test
The B2-7 test is an oxidation test with the following conditions:
lamp
96 hr
Duration
foRp9oNi
oxygen
Flow
:A: NW:kid:id*
ReilitlOiAkkg:41L :7W to aai4
:
Trend data of TBN, AN, pH and Pb ppm
Comments
According to the B2-7 test, the oil to be tested is heated at 300 F for 96
hours with bubbling oxygen.
Copper, iron and lead coupons arecsuspended in the oil. Fifty milliliter
samples are taken at 48, 72
and 96 hours. The samples at 48 and 72 hours are replenished with fresh oil.
The oil test samples are
evaluated for base number, acid number, pH and lead.
26
Table 1. - Comparative Examples
Oil number Comp 1 Comp 2 Comp 3 Comp 4 Comp 5 Comp 6
Comp 7 Comp 8 0
Dispersants
ow
Ethylene 3.00 3.00 3.00 3.00 3.00 3.00
3.00 3.000 W"
Carbonate
ov:'
treated
Wec:'
Succinimide
Dispersant
(wt%)
HOB
263 TBN (22.00) (22.00) (22.00) (22.00) (30.00) (30.00)
(30.00) (30.00)
phenate
(mmol)
2
114 TBN (30.00) (30.00) (30.00) (30.00) (22.00) (22.00)
(22.00) (22.00)
phenate
cnc
(mmol)
cow
350 TBN
carboxylate
Ho"
150 TBN1
carboxylate
Mannich Base 3.00 3.00 3.00 3.00 3.00 3.00
3.00 3.00
Ul
.. ...... ..
........................................................................
...............................................................................
.. ......................................
........................................ .....................................
....................................
............................ ............................
.......................... ......................................
..........................................
......................................
........................................
...................................... ...................................
Diphenylamine 1.00 1.00 1.00 1.00 1.00 1.00
1.00 1.00
(wt%)
Hindered 0.00 1.00 2.00 3.00 0.00 1.00
2.00 3.00
n
Phenol (wt%)
Molybdenum 0.20 0.20 0.20 0.20 0.20 0.20
0.20 0.20
cpw
Oxysulfide
(wt%)
..f.144iii.6iii2223!3!!iii CZEZMMEili CZZZEMMili IEZnMEZ333Mili C33333333Mili
EMEMZEMMMLIMZEZZ22222n!iliZZ3ZZEMEZEil CE3233333iii
ofic:'
1 Prepared according to U.S. Published Patent Application No. 2007/0027043
27
Foam Inhibitor 3ppm 3ppm 3ppm 3ppm 3ppm 3ppm
3ppm 3ppm
ROds
0
i=J
EXXON 150N 5 5 5 5 5 5
5 5
(wt% of total
base oil)
EXXON 600N 95 95 95 95 95 95
95 95
(wt% of total
base oil) i
11.2 TegtEMMiitMEMMaiiLUMMEM]]]
Resutts
TBN decrease 47 5 16 33 5 11 5
534 06
(mg/KOH)
Pb (ppm) 45 647 464 406 925
334 331
cow
H."
c
k
e-
28
Table 2 ¨ Examples of the Invention
Oil number Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6 Ex 7
0
.tiiiiiiiiiiiiing
Succinimide 3.000 3.000 3.000 3.000 3.000 3.000 3.000
Ethylene
..a.,
o
Carbonate
o
o
oe
treated
c,.)
Succinimide
Dispersant
(wt%)
0001:g7:77:77q7:7777777M F:77:77:7771F7777777:1.F77777777:1F:77777771
q7:7777777:1R:77:77:77:771i
:.6iiii:k6iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
UMMIiiiiiiiiiiiiiiiiiiiiiiiii NRRRRI.iiiiiiiiiiiiiiiiiiiiiiiiiLEMillii
350 TBN (22.00) (22.00) (22.00) (30.00) (30.00)
(30.00) (30.00)
carboxylate
n
(mmol)
0
I.)
150 TBN (30.00) (30.00) (30.00) (22.00) (22.00)
(22.00) (22.00) ee
in
carboxylate2
I.)
a,
(mmol)
ee
ee
Mannich Base 3.000 3.000 3.000 3.000 3.000 3.000 3.000
I.)
0
....(wt%)...............................
H
FF.
I
0
FF.
I
48J:iii.fij6ii:1144iiii flai':::::
Miiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii 1.
., .................... igniiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
Miiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiitingiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
iiiiiii H
Diphenylamine 1.00 1.00 1.00 1.00 1.00 1.00 1.00
in
(wt%)
Hindered 1.00 2.00 3.00 0.00 1.00 2.00 3.00
Phenol (wt%)
Molybdenum 0.20 0.20 0.20 0.20 0.20 0.20 0.20
Oxysulfide
Iv
(wt%)n
::************i:
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::
f.'.0ala inummomi
iummommiiiiimmumomii
::::::x:::::::::::::oggnmognommum ummumaa nummogognommum ummumaa
nummugn:.:.mmmmmm:i
1i,t1;tibitotomm,gymp.:.j.i.:.j.i.j.i.j.i.j.i.j.:
gNmp.:.j.i.:.j.i.:.ji.:.j.i.ji.:.:
gmyp.:.j.:.f.:.j.:.j.:.j.:.j.:.j.:.j.:.j.:.j.:.j.:.j.:,:yHmg.:.j.i.:.ji.:.j.i.j
i.:.j.i.ji gNmp.:.j.i.:.j.i.:.ji.:.j.i.ji.:.:
gmyp.:.j.:.f.:.j.:.j.:.j.:.j.:.j.:.j.:.j.:.j.:.j.iii......:mgm....j.......j....
f......j.......j.......j.......j........ii cp
t..,
=
Foam Inhibitor 3ppm 3PPm 3PPm 3PPm 3PPm 3PPm 3PPm
r..)
..a.,
cs
-.4
oe
un
r..)
2 Prepared according to U.S. Published Patent Application No. 2007/0027043
29
E)OCON 150N 5 5 5 5 5 5 5
(wt% of total
0
base oil)
EXXON 600N 95 95 95 95 95 95 95
(wt% of total
base oil)
oo
Results
, . , ......................., ....................... ,
......................... ......................... ,
....................... , ..........................
.......................
TBN decrease 2.94 3.28 3.01 3.57 2.78 3.43 3.54
(mg/KOH)
Pb (ppm) 40 10 26 24 19 28 41
0
co
co
co
0
0
oo
CA 02852488 2014-04-15
WO 2013/090083 PCT/US2012/067852
The samples in the comparative examples (Comparative Examples 1-8) and samples
in the examples of
the invention (Examples 1-7) were evaluated for Total Base Number (TBN)
decrease and lead corrosion
which is measured as parts per million of lead found in the oil (i.e., pb
ppm).
Higher numbers for TBN decrease indicate greater depletion of the base in the
oil and are considered less
favorable. Similarly, higher numbers for pb (ppm) indicate greater lead
corrosion and are considered less
favorable. An oil for extended use in a locomotive diesel engine will ideally
retain TBN and not show
corrosion against lead.
B2-7 Results
Based upon the results of the test it is evident that the lubricating oil
compositions of the invention
Examples 1-7 exhibit lower numbers for TBN decrease, thus indicating that the
base in the lubricating oil
is not depleted as much as in the Comparative Examples. In particular, when
Examples 1-7 are compared
to Comparative Examples 1-8, TBN decrease has improved by more than or equal
to 30%.
Additionally, lead corrosion has decreased in the samples of the oils that are
Examples 1-7. The amount
of lead corrosion is low, especially when compared to the lead corrosion
results of the oils that are
Comparative Examples 1-8. Specifically, the lead corrosion measurements of
Examples 1-7 (of the
invention) show lead measurements that 10-15% of the measurements for the
Comparative Examples.
The lubricating oil compositions, comprising at least two carboxylate
detergents, show a significant
improvement with regard to both TBN retention and lead corrosion over oils
which do not contain the
carboxylates employed in the present invention.
31
