Note: Descriptions are shown in the official language in which they were submitted.
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A METHOD OF REDUCING THE RATE OF DEPLETION OF BASICITY OF A
LUBRICATING OIL COMPOSITION IN USE IN AN ENGINE
FIELD OF THE INVENTION
This invention relates to a method of reducing the rate of depletion of
basicity (as
determined by ASTM D2896) of a lubricating oil composition in use in an
engine, the
lubricating oil composition including at least one oil-soluble overbased
alkali or alkaline
earth metal detergent. In particular, the invention relates to a method of
reducing the rate
of depletion of basicity (as determined by ASTM D2896) of a lubricating oil
composition
in use in an engine, the lubricating oil composition including at least one
oil-soluble
overbased alkali or alkaline earth metal detergent, without increasing
sulphated ash
content (SASH). Preferably, the lubricating oil composition is a marine
cylinder lubricant,
a trunk piston engine oil, a gas engine oil or a crankcase lubricating oil
composition
(including a passenger car motor oil and a heavy duty diesel motor oil).
BACKGROUND OF THE INVENTION
Lubricating oil compositions include oil-soluble overbased detergents to
supply
alkalinity to neutralize sulphur acids resulting from high sulphur fuels. They
also prevent
harmful carbon and sludge deposits, which can lead to engine shut-down and
repair. The
overbased detergents usually have a TBN ranging from 50 to 500, preferably 250
to 450
mg KOH/g (ASTM D2896), and are usually overbased alkaline earth metal
detergents
such as overbased calcium sulphonates, phenates and salicylates. It is
important that the
basicity provided by the overbased detergents be retained as long as possible,
as this
ensures longer oil life and better engine protection over a longer period of
time. It is also
important that ash levels are not increased because excessive sulphated ash
levels can
result in increased deposits on pistons and exhaust gas circuits, including
heat recovery
systems and after-treatment devices.
The present invention is concerned with the problem of reducing the rate of
depletion of basicity (as determined by ASTM D2896) of a lubricating oil
composition in
use in an engine. The present invention is also concerned with the problem of
reducing
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the rate of depletion of basicity (as determined by ASTM D2896) of a
lubricating oil
composition in use in an engine without increasing sulphated ash content.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, there is provided
a
method of reducing the rate of depletion of basicity (as determined by ASTM
D2896) of a
lubricating oil composition in use in an engine, the lubricating oil
composition including at
least one oil-soluble overbased alkali or alkaline earth metal detergent,
which method
comprises adding to the lubricating oil composition one or more compounds of
Formula
(I):
[CH2CH2O]H [CH2CH2O]nH
0 R1 0
¨ R2
H
¨x o)
wherein:
x is 1 to 50, preferably 1 to 40, more preferably 1 to 30;
RI and R2 are H, hydrocarbyl groups having 1 to 12 carbon atoms, or
hydrocarbyl groups
having 1 to 12 carbon atoms and at least one heteroatom:
R is a hydrocarbyl group having 9 to 100, preferably 9 to 70, most preferably,
9 to 50,
carbon atoms; and
n is 0 to 10, or alkaline earth metal salts of the compounds of formula (I).
In the compounds of Formula (1), n is preferably 0. In the compounds of
Formula (I), x is
preferably 1. In the compounds of Formula (I), R is preferably 9 to 20 carbon
atoms, more
preferably 910 15. In the compounds of Formula (I), R is preferably branched.
In the compounds of Formula (I), RI in preferably H, R2 is preferably H and R
is
preferably in the para position in relation to the ¨0¨[CH2CH20]11H group.
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The compounds of Formula (I) are preferably methylene-bridged alkyl phenols or
ethoxylated methylene-bridged alkyl phenols.
The compounds of Formula (I) preferably include less than 1 mole%, more
preferably less than 0.5 mole% and most preferably less than 0.1 mole% of
unreacted
alkyl phenol.
In the compounds of Formula (I), preferably n = 1 for more than 60, more
preferably more than 70, even preferably more than 80, even preferably more
than 90, or
most preferably more than 95, mole %.
In the compounds of Formula (I), preferably n >2, such as di-oxyalkylated, tri-
oxyalkylated and tetra-oxyalkylated, for less than 5 mole %.
The alkaline earth metal salts of the compounds of Formula (I) are, for
example,
calcium, magnesium barium or strontium. Calcium or magnesium is preferred;
calcium is
especially preferred.
The lubricating oil composition is preferably a marine cylinder lubricant, a
trunk
piston engine oil, a gas engine oil or a crankcase lubricating oil composition
(including a
passenger car motor oil and a heavy duty diesel motor oil).
When the lubricating oil composition is a marine cylinder lubricant, the TBN
(as
measured by ASTM D2896) is preferably at least 20, more preferably at least 40
and to
about 70 mgKOH/g.
When the lubricating oil composition is a trunk piston engine oil, the TBN (as
measured by ASTM D2896) is preferably at least 10, more preferably at least
20, and most
preferably 30 to 55 mgKOH/g.
When the lubricating oil composition is a gas engine oil, the TBN (as measured
by
ASTM D2896) is preferably at least 4, more preferably 5 to 15 mgKOH/g.
When the lubricating oil composition is a crankcase oil, the TBN (as measured
by
ASTM D2896) is preferably at least 5, more preferably at least 6 to 18
mgKOH/g.
The lubricating oil composition is preferably a marine cylinder lubricant.
In accordance with the present invention there is also provided use of one or
more
compounds of Formula (I):
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(CH2CH201-,H [CH2CH2O]nH
0 R1 0
¨
H
¨x 0)
wherein: x is 1 to 50, preferably 1 to 40, more preferably 1 to 30; RI and R2
are H,
hydrocarbyl groups having 1 to 12 carbon atoms, or hydrocarbyl groups having 1
to 12
carbon atoms and at least one heteroatom; R is a hydrocarbyl group having 9 to
100,
.. preferably 9 to 70, most preferably, 9 to 50, carbon atoms; and n is 0 to
10, or alkaline
earth metal salts thereof, to reduce the rate of depletion of basicity (as
determined by
ASTM D2896) of a lubricating oil composition in use in an engine, the
lubricating oil
composition including at least one oil-soluble overbased alkali or alkaline
earth metal
detergent.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a graph showing TAN and TBN crossover results.
DETAILED DESCRIPTION OF THE INVENTION
Compounds of Formula (I) are shown below:
[CH2CH20],1-1 [CH2CH2O]nH
0 R1 0
IR2
H
¨x (I)
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x is 1 to 50, preferably 1 to 40, more preferably 1 to 30;
Wand R2 are H, hydrocarbyl groups having 1 to 12 carbon atoms, or hydrocarbyl
groups having
1 to 12 carbon atoms and at least one heteroatom;
R is a hydrocarbyl group having 9 to 100, preferably 9 to 70, most preferably,
9 to 50, carbon
atoms; and
n is 0 to 10, or alkaline earth metal salts thereof.
The alkaline earth metal salts of the compounds of Formula (I) are, for
example,
calcium, magnesium barium or strontium. Calcium or magnesium is preferred;
calcium is
especially preferred.
In the compounds of Formula (I), n is preferably 0. In the compounds of
Formula (I),
x is preferably 1. In the compounds of Formula (I), R is preferably 9 to 20
carbon atoms,
more preferably 9 to 15. In the compounds of Formula (I), R is preferably
branched. In the
compounds of Formula (I), RI and IV are preferably H.
In the compounds of Formula (I), RI in preferably H, R2 is preferably H, R is
preferably
in the para position in relation to the ¨0¨[CH2CH20],,H group, and n is
preferably 1 or more,
preferably 1 to 10. For further details of compounds of Formula (I) when n is
1 or more,
reference is made to EP 2374866A. In the compounds of Formula (I), preferably
n = 1 for more
than 60, more preferably more than 70, even preferably more than 80, even
preferably more
than 90, or most preferably more than 95, mole %. In the compounds of Formula
(I), preferably
n >2, such as di-oxyalkylated, tri-oxyalkylated and tetra-oxyalkylated, for
less than 5 mole %.
The compounds of Formula (I) preferably include less than 1 mole%, more
preferably
less than 0.5 mole% and most preferably less than 0.1 mole% of unreacted alkyl
phenol.
Compounds of formula (I) have the advantage of being free of metals.
Furthermore,
they do not exhibit negative interactions with dispersants.
The compounds of Formula (I) are preferably hydrocarbyl phenol formaldehyde
condensates. The term "hydrocarbyl" as used herein means that R is primarily
composed of
hydrogen and carbon atoms and is bonded to the remainder of the molecule via a
carbon atom,
but does not exclude the presence of other atoms or groups in a proportion
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insufficient to detract from the substantially hydrocarbon characteristics of
the group. The
hydrocarbyl group is preferably composed of only hydrogen and carbon atoms.
Advantageously, the hydrocarbyl group is an aliphatic group, preferably alkyl
or alkylene
group, especially alkyl groups, which may be linear or branched. R is
preferably an alkyl
.. or alkylene group. R is preferably branched.
The hydrocarbyl phenol aldehyde condensate preferably has a weight average
molecular weight (Mw), as measured by GPC, in the range of 1000 to less than
6000,
preferably less than 4000. The hydrocarbyl phenol aldehyde condensate
preferably has a
number average molecular weight (Mn), as measured by GPC, in the range of 900
to less
0 than 4000, such as 3000. Mw/Mn is preferably in the range of 1.10 to
1.60.
The hydrocarbyl phenol aldehyde condensate is preferably one obtained by a
condensation reaction between at least one aldehyde or ketone or reactive
equivalent
thereof and at least one hydrocarbyl phenol, in the presence of an acid
catalyst such as, for
example, an alkyl benzene sulphonic acid. The product is preferably subjected
to stripping
to remove any unreacted hydrocarbyl phenol, preferably to less than 5 mass %,
more
preferably to less than 3 mass %, even more preferably to less than 1 mass %,
of unreacted
hydrocarbyl phenol. Most preferably, the product includes less than 0.5 mass
%, such as,
for example, less than 0.1 mass % of unreacted hydrocarbyl phenol.
Although a basic catalyst can be used, an acid catalyst is preferred. The acid
.. catalyst may be selected from a wide variety of acidic compounds such as,
for example,
phosphoric acid, sulphuric acid, sulphonic acid, oxalic acid and hydrochloric
acid. The
acid may also be present as a component of a solid material such as acid
treated clay. The
amount of catalyst used may vary from 0.05 to 10 mass % or more, such as for
example
0.1 to 1 mass % of the total reaction mixture.
When n is 1 or more in Formula (I), the compounds are preferably made by
oxyalkylating a hydrocarbyl phenol condensate with ethylene carbonate (which
is
preferred), propylene carbonate or butylene carbonate. Use of a carbonate for
the
oxyalkylation reaction is found to give rise to much better control of the "n"
value and
quantity, in comparison with use of ethylene oxide or propylene oxide.
Furthermore, an
appropriate choice of catalyst can provide a product consisting essentially
entirely of
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mono-oxyalkyl (i.e. n = 1) content. Sodium salts are preferred, especially the
hydroxide
and carboxylates, such as stearate.
In particular, the hydrocarbyl phenol aldehyde condensate is preferably
branched
dodecyl phenol formaldehyde condensate, such as, for example, a tetrapropenyl
tetramer
phenol formaldehyde condensate.
The hydrocarbyl phenol aldehyde condensate is preferably present in the
additive
concentrate in an amount ranging from about 0.1 to 20 mass %, preferably from
about 0.1
to 15 mass %, and more preferably from about 0.1 to 12 mass %, based on the
mass of the
concentrate.
Lubricating oil compositions of the present invention comprise a major amount
of
an oil of lubricating viscosity and a minor amount of a compound of Formula I.
Oils of lubricating viscosity useful in the context of the present invention
may be
selected from natural lubricating oils, synthetic lubricating oils and
mixtures thereof. The
lubricating oil may range in viscosity from light distillate mineral oils to
heavy lubricating
oils such as gasoline engine oils, mineral lubricating oils and heavy duty
diesel oils.
Generally, the viscosity of the oil ranges from about 2 centistokes to about
40 centistokes,
especially from about 4 centistokcs to about 20 ccntistokes, as measured at
100 C.
Natural oils include animal oils and vegetable oils (e.g., castor oil, lard
oil); liquid
petroleum oils and hydrorefined, solvent-treated or acid-treated mineral oils
of the
paraffinic, naphthenic and mixed paraffinic-naphthenic types. Oils of
lubricating viscosity
derived from coal or shale also serve as useful base oils.
Synthetic lubricating oils include hydrocarbon oils and halo-substituted
hydrocarbon oils
such as polymerized and interpolymerized olefins (e.g., polybutylenes,
polypropylenes,
propylene-isobutylene copolymers, chlorinated polybutylenes, poly(1-hexenes),
poly(1-
octenes), poly(1-decenes)); alkylbenzenes (e.g., dodecylbenzenes,
tetradecylbenzenes,
dinonylbenzenes, di(2-ethylhexyl)benzenes); polyphenyls (e.g., biphenyl s,
terphenyls,
alkylated polyphenols); and alkylated diphenyl ethers and alkylated diphenyl
sulfides and
derivative, analogs and homologs thereof. Also useful are synthetic oils
derived from a
gas to liquid process from Fischer-Tropsch synthesized hydrocarbons, which are
commonly referred to as gas to liquid, or "GTL" base oils.
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Alkylene oxide polymers and interpolymers and derivatives thereof where the
terminal hydroxyl groups have been modified by esterification, etherification,
etc.,
constitute another class of known synthetic lubricating oils. These are
exemplified by
polyoxyalkylene polymers prepared by polymerization of ethylene oxide or
propylene
.. oxide, and the alkyl and aryl ethers of polyoxyalkylene polymers (e.g.,
methyl-polyiso-
propylene glycol ether having a molecular weight of 1000 or diphenyl ether of
poly-
ethylene glycol having a molecular weight of 1000 to 1500); and mono- and
polycarboxylic esters thereof, for example, the acetic acid esters, mixed C3-
C8 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, maleic acid, azelaie acid, suberic acid, sebasic acid, fumaric
acid, adipic
acid, linoleic acid dimer, malonic acid, alkylmalonic acids, alkenyl malonic
acids) with a
variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-
ethylhexyl
alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol).
Specific
examples of such esters includes 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.
Esters useful as synthetic oils also include those made from C5 to C12
monocarboxylic acids and polyols and polyol esters such as neopentyl glycol,
trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.
Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy- or
polyaryloxysilicone oils and silicate oils comprise another useful class of
synthetic
lubricants; such oils include tetraethyl silicate, tetraisopropyl silicate,
tetra-(2-
ethylhexyl)silicate, tetra-(4-methyl-2-ethylhexyl)silicate, tetra-(p-tert-
butyl-phenyl)
silicate, hexa-(4-methyl-2-ethylhexyl)disiloxane, poly(methyl)siloxanes and
poly(methylphenyl)siloxanes. Other synthetic lubricating oils include liquid
esters of
phosphorous-containing acids (e.g., tricresyl phosphate, trioctyl phosphate,
diethyl ester of
decylphosphonic acid) and polymeric tetrahydrofurans.
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The oil of lubricating viscosity may comprise a Group I, Group II or Group
III,
base stock or base oil blends of the aforementioned base stocks. Preferably,
the oil of
lubricating viscosity is a Group II or Group III base stock, or a mixture
thereof, or a
mixture of a Group I base stock and one or more a Group II and Group III.
Preferably, a
major amount of the oil of lubricating viscosity is a Group II, Group III,
Group IV or
Group V base stock, or a mixture thereof. The base stock, or base stock blend
preferably
has a saturate content of at least 65%, more preferably at least 75%, such as
at least 85%.
Most preferably, the base stock, or base stock blend, has a saturate content
of greater than
90%. Preferably, the oil or oil blend will have a sulfur content of less than
1%, preferably
less than 0.6%, most preferably less than 0.4%, by weight.
Preferably the volatility of the oil or oil blend, as measured by the Noack
volatility
test (ASTM D5880), is less than or equal to 30%, preferably less than or equal
to 25%,
more preferably less than or equal to 20%, most preferably less than or equal
16%.
Preferably, the viscosity index (VI) of the oil or oil blend is at least 85,
preferably at least
100, most preferably from about 105 to 140.
Definitions for the base stocks and base oils in this invention arc the same
as those
found in the American Petroleum Institute (API) publication "Engine Oil
Licensing and
Certification System", Industry Services Department, Fourteenth Edition,
December 1996,
Addendum 1, December 1998. Said publication categorizes base stocks as
follows:
a) Group I base stocks contain less than 90 percent saturates and/or
greater
than 0.03 percent sulfur and have a viscosity index greater than or equal to
80 and less than 120 using the test methods specified in Table 1.
b) Group II base stocks contain greater than or equal to 90 percent
saturates
and less than or equal to 0.03 percent sulfur and have a viscosity index
greater than or equal to 80 and less than 120 using the test methods
specified in Table 1.
c) Group III base stocks contain greater than or equal to 90 percent
saturates
and less than or equal to 0.03 percent sulfur and have a viscosity index
greater than or equal to 120 using the test methods specified in Table 1.
d) Group IV base stocks are polyalphaolefins (PAO).
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e) Group V base stocks include all other base stocks not included
in Group I,
II, III, or IV.
Table I - Analytical Methods for Base Stock
Property Test Method
Saturates ASTM D 2007
Viscosity Index ASTM D 2270
Sulfur ASTM D 2622
ASTM D 4294
ASTM D 4927
ASTM D 3120
Metal-containing or ash-forming detergents function both as detergents to
reduce or
remove deposits and as acid neutralizers or rust inhibitors, thereby reducing
wear and
corrosion and extending engine life. Detergents generally comprise a polar
head with a
long hydrophobic tail, with the polar head comprising a metal salt of an
acidic organic
compound. The salts may contain a substantially stoichiometric amount of the
metal in
which case they are usually described as normal or neutral salts, and would
typically have
a total base number or TBN (as can be measured by ASTM D2896) of from 0 to 80.
A
large amount of a metal base may be incorporated by reacting excess metal
compound
(e.g., an oxide or hydroxide) with an acidic gas (e.g., carbon dioxide). The
resulting
overbased detergent comprises neutralized detergent as the outer layer of a
metal base (e.g.
carbonate) micelle. Such overbased detergents may have a TBN of 150 or
greater, and
typically will have a TBN of from 250 to 500 or more.
Detergents that may be used include oil-soluble neutral and overbased
sulfonates,
phenates, sulfurized phenates, thiophosphonates, salicylates, and naphthenates
and other
oil-soluble carboxylates of a metal, particularly the alkali or alkaline earth
metals, e.g.,
sodium, potassium, lithium, calcium, and magnesium. The most commonly used
metals
are calcium and magnesium, which may both be present in detergents used in a
lubricant,
and mixtures of calcium and/or magnesium with sodium. Particularly convenient
metal
detergents are neutral and overbased calcium sulfonates having TBN of from 20
to 500
TBN, and neutral and overbased calcium phenates and sulfurized phenates having
TBN of
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from 50 to 450. Combinations of detergents, whether overbased or neutral or
both, may
be used.
Sulfonates may be prepared from sulfonic acids which are typically obtained by
the sulfonation of alkyl substituted aromatic hydrocarbons such as those
obtained from the
fractionation of petroleum or by the alkylation of aromatic hydrocarbons.
Examples
included those obtained by alkylating benzene, toluene, xylene, naphthalene,
diphenyl or
their halogen derivatives such as chlorobenzene, chlorotoluene and
chloronaphthalene.
The alkylation may be carried out in the presence of a catalyst with
alkylating agents
having from about 3 to more than 70 carbon atoms. The alkaryl sulfonates
usually contain
.. from about 9 to about 80 or more carbon atoms, preferably from about 16 to
about 60
carbon atoms per alkyl substituted aromatic moiety.
The oil soluble sulfonates or alkaryl sulfonic acids may be neutralized with
oxides,
hydroxides, alkoxides, carbonates, carboxylate, sulfides, hydrosulfides,
nitrates, borates
and ethers of the metal. The amount of metal compound is chosen having regard
to the
desired TBN of the final product but typically ranges from about 100 to 220
mass %
(preferably at least 125 mass %) of that stoichiometrically required.
Metal salts of phenols and sulfurized phenols arc prepared by reaction with an
appropriate metal compound such as an oxide or hydroxide and neutral or
overbased
products may be obtained by methods well known in the art. Sulfurized phenols
may be
prepared by reacting a phenol with sulfur or a sulfur containing compound such
as
hydrogen sulfide, sulfur monohalide or sulfur dihalide, to form products which
are
generally mixtures of compounds in which 2 or more phenols are bridged by
sulfur
containing bridges.
Lubricating oil compositions of the present invention may further contain one
or
more ashless dispersants, which effectively reduce formation of deposits upon
use in
engines, when added to lubricating oils. Ashless dispersants useful in the
compositions of
the present invention comprises an oil soluble polymeric long chain backbone
having
functional groups capable of associating with particles to be dispersed.
Typically, such
dispersants comprise amine, alcohol, amide or ester polar moieties attached to
the polymer
backbone, often via a bridging group. The ashless dispersant may be, for
example,
selected from oil soluble salts, esters, amino-esters, amides, imides and
oxazolines of long
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chain hydrocarbon-substituted mono- and polycarboxylic acids or anhydrides
thereof:
thiocarboxylate derivatives of long chain hydrocarbons; long chain aliphatic
hydrocarbons
having poly-amine moieties attached directly thereto; and Mannich condensation
products
formed by condensing a long chain substituted phenol with formaldehyde and
polyalkylene polyamine. The most common dispersant in use is the well known
succinimide dispersant, which is a condensation product of a hydrocarbyl-
substituted
succinic anhydride and a poly(alkyleneamine). Both mono-succinimide and bis-
succinimide dispersants (and mixtures thereof) are well known.
Preferably, the ashless dispersant is a "high molecular weight" dispersant
having a
number average molecular weight (M.) greater than or equal to 4,000, such as
between
4,000 and 20,000. The precise molecular weight ranges will depend on the type
of
polymer used to form the dispersant, the number of functional groups present,
and the type
of polar functional group employed. For example, for a polyisobutylene
derivatized
dispersant, a high molecular weight dispersant is one formed with a polymer
backbone
having a number average molecular weight of from about 1680 to about 5600.
Typical
commercially available polyisobutylene-based dispersants contain
polyisobutylene
polymers having a number average molecular weight ranging from about 900 to
about
2300, functionalized by maleic anhydride (MW = 98), and derivatized with
polyamines
having a molecular weight of from about 100 to about 350. Polymers of lower
molecular
weight may also be used to form high molecular weight dispersants by
incorporating
multiple polymer chains into the dispersant, which can be accomplished using
methods
that are know in the art.
Preferred groups of dispersant include polyamine-derivatized poly a-olefin,
dispersants, particularly ethylene/butene alpha-olefin and polyisobutylene-
based
.. dispersants. Particularly preferred are ashless dispersants derived from
polyisobutylene
substituted with succinic anhydride groups and reacted with polyethylene
amines, e.g.,
polyethylene diamine, tetraethylene pentamine; or a polyoxyalkylene polyamine,
e.g.,
polyoxypropylene diamine, trimethylolaminomethane; a hydroxy compound, e.g.,
pentaerythritol; and combinations thereof. One particularly preferred
dispersant
combination is a combination of (A) polyisobutylene substituted with succinic
anhydride
groups and reacted with (B) a hydroxy compound, e.g., pentaerythritol; (C) a
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polyoxyalkylene polyamine, e.g., polyoxypropylene diamine, or (D) a
polyalkylene
diamine, e.g.. polyethylene diamine and tetraethylene pentamine using about
0.3 to about
2 moles of (B), (C) and/or (D) per mole of (A). Another preferred dispersant
combination
comprises a combination of (A) polyisobutenyl succinic anhydride with (B) a
polyalkylene
polyamine, e.g., tetraethylene pentamine, and (C) a polyhydric alcohol or
polyhydroxy-
substituted aliphatic primary amine, e.g., pentaerythritol or
trismethylolaminomethane, as
described in U.S. Patent No. 3,632,511.
Another class of ashless dispersants comprises Mannich base condensation
products. Generally, these products are prepared by condensing about one mole
of an
alkyl-substituted mono- or polyhydroxy benzene with about 1 to 2.5 moles of
carbonyl
compound(s) (e.g., formaldehyde and paraformaldehyde) and about 0.5 to 2 moles
of
polyalkylene polyamine, as disclosed, for example, in U.S. Patent No.
3,442,808. Such
Mannich base condensation products may include a polymer product of a
metallocene
catalyzed polymerization as a substituent on the benzene group, or may be
reacted with a
compound containing such a polymer substituted on a succinic anhydride in a
manner
similar to that described in U.S. Patent No. 3,442,808. Examples of
functionalized and/or
derivatized olefin polymers synthesized using metallocene catalyst systems are
described
in the publications identified supra.
The dispersant can be further post treated by a variety of conventional post
treatments such as boration, as generally taught in U.S. Patent Nos. 3,087,936
and
3,254,025. Boration of the dispersant is readily accomplished by treating an
acyl nitrogen-
containing dispersant with a boron compound such as boron oxide, boron halide
boron
acids, and esters of boron acids, in an amount sufficient to provide from
about 0.1 to about
20 atomic proportions of boron for each mole of acylated nitrogen composition.
Useful
dispersants contain from about 0.05 to about 2.0 mass %, e.g., from about 0.05
to about
0.7 mass % boron. The boron, which appears in the product as dehydrated boric
acid
polymers (primarily (HB02)3), is believed to attach to the dispersant imides
and diimides
as amine salts, e.g., the metaborate salt of the diimide. Boration can be
carried out by
adding from about 0.5 to 4 mass %, e.g., from about 1 to about 3 mass % (based
on the
mass of acyl nitrogen compound) of a boron compound, preferably boric acid,
usually as a
slurry, to the acyl nitrogen compound and heating with stirring at from about
135 C to
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about 190 C, e.g., 140 C to 170 C, for from about 1 to about 5 hours, followed
by
nitrogen stripping. Alternatively, the boron treatment can be conducted by
adding boric
acid to a hot reaction mixture of the dicarboxylic acid material and amine,
while removing
water. Other post reaction processes commonly known in the art can also be
applied.
The dispersant may also be further post treated by reaction with a so-called
"capping agent". Conventionally, nitrogen-containing dispersants have been
"capped" to
reduce the adverse effect such dispersants have on the fluoroelastomer engine
seals.
Numerous capping agents and methods are known. Of the known "capping agents",
those
that convert basic dispersant amino groups to non-basic moieties (e.g., amido
or imido
to groups) are most suitable. The reaction of a nitrogen-containing
dispersant and alkyl
acetoacetate (e.g., ethyl acetoacetate (EAA)) is described, for example, in
U.S. Patent Nos.
4,839,071; 4,839,072 and 4,579,675. The reaction of a nitrogen-containing
dispersant and
formic acid is described, for example, in U.S. Patent No. 3,185,704. The
reaction product
of a nitrogen-containing dispersant and other suitable capping agents are
described in U.S.
Patent Nos. 4,663,064 (glycolic acid); 4,612,132; 5,334,321; 5,356,552;
5,716,912;
5,849,676; 5,861,363 (alkyl and alkylene carbonates, e.g., ethylene
carbonate); 5,328,622
(mono-epoxide); 5,026,495; 5,085,788; 5,259,906; 5,407,591 (poly (e.g., bis)-
epoxides)
and 4,686,054 (maleic anhydride or succinie anhydride). The foregoing list is
not
exhaustive and other methods of capping nitrogen-containing dispersants are
known to
those skilled in the art.
For adequate piston deposit control, a nitrogen-containing dispersant can be
added
in an amount providing the lubricating oil composition with from about 0.03
mass % to
about 0.15 mass %, preferably from about 0.07 to about 0.12 mass %, of
nitrogen.
Ashless dispersants are basic in nature and therefore have a TBN which,
depending
on the nature of the polar group and whether or not the dispersant is borated
or treated
with a capping agent, may be from about 5 to about 200 mg KOH/g. However, high
levels
of basic dispersant nitrogen are known to have a deleterious effect on the
fluoroelastomeric materials conventionally used to form engine seals and,
therefore, it is
preferable to use the minimum amount of dispersant necessary to provide piston
deposit
control, and to use substantially no dispersant, or preferably no dispersant,
having a TBN
of greater than 5. Preferably, the amount of dispersant employed will
contribute no more
CA 02799378 2012-12-20
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than 4, preferably no more than 3 mg KOH/g of TBN to the lubricating oil
composition. It
is further preferable that dispersant provides no greater than 30, preferably
no greater than
25% of the TBN of the lubricating oil composition.
Additional additives may be incorporated in the compositions of the invention
to
enable them to meet particular requirements. Examples of additives which may
be
included in the lubricating oil compositions are metal rust inhibitors,
viscosity index
improvers, corrosion inhibitors, oxidation inhibitors, friction modifiers,
other dispersants,
anti-foaming agents, anti-wear agents and pour point depressants. Some are
discussed in
further detail below.
Dihydrocarbyl dithiophosphate metal salts are frequently used as antiwear and
antioxidant agents. The metal may be an alkali or alkaline earth metal, or
aluminum, lead,
tin, molybdenum, manganese, nickel or copper. The zinc salts are most commonly
used in
lubricating oil in amounts of 0.1 to 10, preferably 0.2 to 2 wt. %, based upon
the total
weight of the lubricating oil composition. They may be prepared in accordance
with
known techniques by first forming a dihydrocarbyl dithiophosphoric acid
(DDPA), usually
by reaction of one or more alcohol or a phenol with P2S5 and then neutralizing
the formed
DDPA with a zinc compound. For example, a dithiophosphoric acid may be made by
reacting mixtures of primary and secondary alcohols. Alternatively, multiple
dithiophosphoric acids can be prepared where the hydrocarbyl groups on one are
entirely
secondary in character and the hydrocarbyl groups on the others are entirely
primary in
character. To make the zinc salt, any basic or neutral zinc compound could be
used but
the oxides, hydroxides and carbonates are most generally employed. Commercial
additives frequently contain an excess of zinc due to the use of an excess of
the basic zinc
compound in the neutralization reaction.
The preferred zinc dihydrocarbyl dithiophosphates are oil soluble salts of
dihydrocarbyl dithiophosphoric acids and may be represented by the following
formula:
RO '
S Zn
R10
¨2
CA 02799378 2012-12-20
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wherein R and R' may be the same or different hydrocarbyl radicals containing
from 1 to
18, preferably 2 to 12, carbon atoms and including radicals such as alkyl,
alkenyl, aryl,
arylalkyl, alkaryl and cycloaliphatic radicals. Particularly preferred as R
and R' groups
are alkyl groups of 2 to 8 carbon atoms. Thus, the radicals may, for example,
be ethyl, n-
propyl, i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-
octyl, decyl, dodecyl,
octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl,
propenyl,
butenyl. In order to obtain oil solubility. the total number of carbon atoms
(i.e. R and R')
in the dithiophosphoric acid will generally be about 5 or greater. The zinc
dihydrocarbyl
dithiophosphate can therefore comprise zinc dialkyl dithiophosphates. The
present
invention may be particularly useful when used with lubricant compositions
containing
phosphorus levels of from about 0.02 to about 0.12 mass %, such as from about
0.03 to
about 0.10 mass %, or from about 0.05 to about 0.08 mass %, based on the total
mass of
the composition. In one preferred embodiment, lubricating oil compositions of
the present
invention contain zinc dialkyl dithiophosphate derived predominantly (e.g.,
over 50
mol. %, such as over 60 mol. %) from secondary alcohols.
Oxidation inhibitors or antioxidants reduce the tendency of mineral oils to
deteriorate in service. Oxidative deterioration can be evidenced by sludge in
the lubricant,
varnish-like deposits on the metal surfaces, and by viscosity growth. Such
oxidation
inhibitors include hindered phenols, alkaline earth metal salts of
alkylphenolthioesters
having preferably C5 to C12 alkyl side chains, calcium nonylphenol sulfide,
oil soluble
phenates and sulfurized phenates, phosphosulfurized or sulfurized
hydrocarbons,
phosphorous esters, metal thiocarbamates, oil soluble copper compounds as
described in
U.S. Patent No. 4,867,890, and molybdenum-containing compounds.
Typical oil soluble aromatic amines having at least two aromatic groups
attached
directly to one amine nitrogen contain from 6 to 16 carbon atoms. The amines
may
contain more than two aromatic groups. Compounds having a total of at least
three
aromatic groups in which two aromatic groups are linked by a covalent bond or
by an
atom or group (e.g., an oxygen or sulfur atom, or a -CO-, -SO2- or alkylene
group) and
two are directly attached to one amine nitrogen also considered aromatic
amines having at
least two aromatic groups attached directly to the nitrogen. The aromatic
rings are
CA 02799378 2012-12-20
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typically substituted by one or more substituents selected from alkyl,
cycloalkyl, alkoxy,
aryloxy, acyl, acylamino, hydroxy, and nitro groups.
Multiple antioxidants are commonly employed in combination. In one preferred
embodiment, lubricating oil compositions of the present invention contain from
about 0.1
to about 1.2 mass % of aminic antioxidant and from about 0.1 to about 3 mass %
of
phenolic antioxidant. In another preferred embodiment, lubricating oil
compositions of
the present invention contain from about 0.1 to about 1.2 mass % of aminic
antioxidant,
from about 0.1 to about 3 mass % of phenolic antioxidant and a molybdenum
compound
in an amount providing the lubricating oil composition from about 10 to about
1000 ppm
.. of molybdenum.
Representative examples of suitable viscosity modifiers are polyisobutylene,
copolymers of ethylene and propylene, polymethacrylates, methacrylate
copolymers,
copolymers of an unsaturated dicarboxylic acid and a vinyl compound,
interpolymers of
styrene and acrylic esters, and partially hydrogenated copolymers of styrene/
isoprene,
styrene/butadiene, and isoprene/butadiene, as well as the partially
hydrogenated
homopolymers of butadiene and isoprene.
Friction modifiers and fuel economy agents that are compatible with the other
ingredients of the final oil may also be included. Examples of such materials
include
glyceryl monoesters of higher fatty acids, for example, glyceryl mono-oleate;
esters of
long chain polycarboxylic acids with diols, for example, the butane diol ester
of a
dimerized unsaturated fatty acid; oxazoline compounds; and alkoxylated alkyl-
substituted
mono-amines, diamines and alkyl ether amines, for example, ethoxylated tallow
amine
and ethoxylated tallow ether amine.
Other known friction modifiers comprise oil-soluble organo-molybdenum
compounds. Such organo-molybdenum friction modifiers also provide antioxidant
and
antiwear credits to a lubricating oil composition. Examples of such oil
soluble organo-
molybdenum compounds include dithiocarbamates, dithiophosphates,
dithiophosphinates,
xanthates, thioxanthates, sulfides, and the like, and mixtures thereof.
Particularly preferred
are molybdenum dithiocarbamates, dialkyldithiophosphates, alkyl xanthates and
alkylthioxanthates.
CA 02799378 2012-12-20
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Additionally, the molybdenum compound may be an acidic molybdenum
compound. These compounds will react with a basic nitrogen compound as
measured by
ASTM test D-664 or D-2896 titration procedure and are typically hexavalent.
Included
are molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate,
and
other alkaline metal molybdates and other molybdenum salts, e.g., hydrogen
sodium
molybdate, Mo0C14, Mo0213r2, Mo203C16, molybdenum trioxide or similar acidic
molybdenum compounds.
Among the molybdenum compounds useful in the compositions of this invention
are
organo-molybdenum compounds of the formulae:
Mo(ROCS2)4 and
Mo(RSCS))4
wherein R is an organo group selected from the group consisting of alkyl,
aryl, aralkyl and
alkoxyalkyl, generally of from Ito 30 carbon atoms, and preferably 2 to 12
carbon atoms and
most preferably alkyl of 2 to 12 carbon atoms. Especially preferred are the
dialkyldithiocarbamates of molybdenum.
Another group of organo-molybdenum compounds useful in the lubricating
compositions of this invention are trinuclear molybdenum compounds, especially
those of the
formula Mo3SkLnQ7 and mixtures thereof wherein the L are independently
selected ligands
having organo groups with a sufficient number of carbon atoms to render the
compound
soluble or dispersible in the oil, n is from 1 to 4, k varies from 4 through
7, Q is selected from
the group of neutral electron donating compounds such as water, amines,
alcohols,
phosphines, and ethers, and z ranges from 0 to 5 and includes non-
stoichiometric values. At
least 21 total carbon atoms should be present among all the ligand organo
groups, such as at
least 25, at least 30, or at least 35 carbon atoms.
A dispersant-viscosity index improver functions as both a viscosity index
improver
and as a dispersant. Examples of dispersant-viscosity index improvers include
reaction
products of amines, for example polyamines, with a hydrocarbyl-substituted
mono-or di-
carboxylic acid in which the hydrocarbyl substituent comprises a chain of
sufficient length
to impart viscosity index improving properties to the compounds. In general,
the viscosity
index improver dispersant may be, for example, a polymer of a C4 to C24
unsaturated ester
of vinyl alcohol or a C3 to C10 unsaturated mono-carboxylic acid or a C4 to
C10 di-
CA 02799378 2012-12-20
- 19 -
carboxylic acid with an unsaturated nitrogen-containing monomer having 4 to 20
carbon
atoms; a polymer of a C2 to C20 olefin with an unsaturated C3 to Ci0 mono- or
di-
carboxylic acid neutralized with an amine, hydroxyl amine or an alcohol; or a
polymer of
ethylene with a C3 to C20 olefin further reacted either by grafting a C4 to
C20 unsaturated
nitrogen-containing monomer thereon or by grafting an unsaturated acid onto
the polymer
backbone and then reacting carboxylic acid groups of the grafted acid with an
amine,
hydroxy amine or alcohol.
Pour point depressants, otherwise known as lube oil flow improvers (LOFT),
lower
the minimum temperature at which the fluid will flow or can be poured. Such
additives
are well known. Typical of those additives that improve the low temperature
fluidity of
the fluid are C8 to C18 dialkyl fumarate/vinyl acetate copolymers, and
polymcthacrylates.
Foam control can be provided by an antifoamant of the polysiloxane type, for
example,
silicone oil or polydimethyl siloxane.
Some of the above-mentioned additives can provide a multiplicity of effects;
thus
for example, a single additive may act as a dispersant-oxidation inhibitor.
This approach
is well known and need not be further elaborated herein.
In the present invention it may also be preferable to include an additive
which
maintains the stability of the viscosity of the blend. Thus, although polar
group-containing
additives achieve a suitably low viscosity in the pre-blending stage it has
been observed
that some compositions increase in viscosity when stored for prolonged
periods.
Additives which are effective in controlling this viscosity increase include
the long chain
hydrocarbons functionalized by reaction with mono- or dicarboxylic acids or
anhydrides
which are used in the preparation of the ashless dispersants as hereinbefore
disclosed.
When lubricating compositions contain one or more of the above-mentioned
additives, each additive is typically blended into the base oil in an amount
that enables the
additive to provide its desired function. Representative effect amounts of
such additives,
when used in different lubricants, are listed below. All the values listed are
stated as mass
percent active ingredient.
CA 02799378 2012-12-20
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Marine Diesel Cylinder Lubricant ("MDCL")
A Marine Diesel Cylinder Lubricant may employ 10-35, preferably 13-30, most
preferably 16-24, mass % of a concentrate or additive package, the remainder
being base
stock. It preferably includes at least 50, more preferably at least 60, even
more preferably
at least 70, mass % of oil of lubricating viscosity based on the total mass of
MDCL.
Fully formulated MDCLs preferably have a TBN of at least 20, such as from
about
30 to about 100 mg KOH/g (ASTM D2896). More preferably, compositions have a
TBN
of at least 40, such as from about 40 to about 70 mg KOH/g.
MDCLs preferably have a sulfated ash (SASH) content (ASTM D-874) of about
12 mass % or less, preferably about 11 mass % or less, more preferably about
10 mass %
or less, such as 9 mass % or less.
The following may be mentioned as examples of typical proportions of additives
in
an MDCL:
Additive Mass% a.i. Mass% a.i.
(Broad) (Preferred)
detergent(s) 1-20 3-15
dispersant(s) 0.5-5 1-3
ashless anti-wear agent(s) 0.1-1.5 0.5-1.3
pour point dispersant 0.03-1.15 0.05-0.1
base stock balance balance
Trunk Piston Engine Oil ("TPEO")
A Trunk Piston Engine Oil may employ 7-35, preferably 10-28, more preferably
12-24, mass % of a concentrate or additives package, the remainder being base
stock.
Fully formulated trunk piston engine oils preferably have a TBN of at least
10,
such as from about 15 to about 60 mg KOH/g (ASTM D2896). More preferably,
compositions have a TBN of at least 20, such as from about 30 to about 55 mg
KOH/g.
CA 02799378 2012-12-20
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Fully formulated trunk piston engine oils preferably have a sulfated ash
(SASH)
content (ASTM D-874) of about 7 mass % or less, preferably about 6.5 mass % or
less,
such as 6.3 mass % or less.
The following may be mentioned as typical proportions of additives in a TPEO:
Additive Mass% a.i. Mass% a.i.
(Broad) (Preferred)
detergent(s) 0.5-12 2-8
dispersant(s) 0.5-5 1-3
ashless anti-wear agent(s) 0.1-1.5 0.5-1.3
oxidation inhibitor 0.2-2 0.5-1.5
rust inhibitor 0.03-0.15 0.05-0.1
pour point dispersant 0.03-1.15 0.05-0.1
base stock balance balance
Crankcase Lubricant
Fully formulated crankcase lubricating oil compositions preferably have a TBN
of
at least 6, such as from about 6 to about 18 mg KOH/g (ASTM D2896). More
preferably,
compositions have a TBN of at least 8.5, such as from about 8.5 or 9 to about
18 mg
KOH/g.
Fully formulated crankcase lubricating oil compositions preferably have a
sulfated
ash (SASH) content (ASTM D-874) of about 1.1 mass % or less, preferably about
1.0
mass % or less, more preferably about 0.8 mass % or less, such as 0.5 mass %
or less.
The following may be mentioned as examples of typical proportions of additives
in
a crankcase lubricant (including passenger car motor oil and heavy duty diesel
motor oil):
CA 02799378 2012-12-20
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Additive Mass% a.i. Mass% a.i.
(Broad) (Preferred)
Metal Detergents 0.1 - 15 0.2 - 9
Corrosion Inhibitor 0 - 5 0 - 1.5
Metal Dihydrocarbyl Dithiophosphate 0.1 -6 0.1 -4
Antioxidant 0 - 5 0.01 - 3
Pour Point Depressant 0.01 - 5 0.01 - 1.5
Antifoaming Agent 0 - 5 0.001 - 0.15
Supplemental Antiwear Agents 0 - 1.0 0 - 0.5
Friction Modifier 0 - 5 0 - 1.5
Viscosity Modifier 0.01 - 10 0.25 - 3
Basestock Balance Balance
Fully formulated lubricating oil compositions of the present invention
preferably
have a sulfur content of less than about 0.4 mass %. For crankcase
applications, the fully
formulated lubricating oil compositions preferably have a sulfur content of
less than about
0.35 mass % more preferably less than about 0.3 mass %, such as less than
about 0.20
mass %. Preferably, the Noack volatility (ASTM D5880) of the fully formulated
lubricating oil composition (oil of lubricating viscosity plus all additives
and additive
diluent) will be no greater than 13, such as no greater than 12, preferably no
greater than
o 10. Fully formulated lubricating oil compositions of the present
invention preferably have
no greater than 1200 ppm of phosphorus, such as no greater than 1000 ppm of
phosphorus,
or no greater than 800 ppm of phosphorus, such as no greater than 600 ppm of
phosphorus,
or no greater than 500 or 400 ppm of phosphorus.
It may be desirable, although not essential to prepare one or more additive
concentrates comprising additives (concentrates sometimes being referred to as
additive
packages) whereby several additives can be added simultaneously to the 'oil to
form the
lubricating oil composition. A concentration for the preparation of a
lubricating oil
composition of the present invention may, for example, contain from about 0.1
to about 30
mass %, preferably from 0.5 to 30 mass%, of one or more compounds of Formula
(I);
about 10 to about 40 mass % of a nitrogen-containing dispersant; about 2 to
about 20
mass % of an aminic antioxidant, a phenolic antioxidant, a molybdenum
compound, or a
CA 02799378 2012-12-20
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mixture thereof; about 5 to 40 mass % of a detergent; and from about 2 to
about 20
mass % of a metal dihydrocarbyl dithiophosphate.
The final composition may employ from 5 to 25 mass %, preferably 5 to 18
mass %, typically 10 to 15 mass % of the concentrate, the remainder being oil
of
lubricating viscosity and viscosity modifier.
All weight (and mass) percents expressed herein (unless otherwise indicated)
are
based on active ingredient (A.I.) content of the additive, and/or additive-
package,
exclusive of any associated diluent. However, detergents are conventionally
formed in
diluent oil, which is not removed from the product, and the TBN of a detergent
is
conventionally provided for the active detergent in the associated diluent
oil. Therefore.
weight (and mass) percents, when referring to detergents are (unless otherwise
indicated)
total weight (or mass) percent of active ingredient and associated diluent
oil.
This invention will be further understood by reference to the following
examples,
wherein all parts are parts by weight (or mass), unless otherwise noted.
EXAMPLES
It is important that the basicity introduced into a lubricating oil
composition be
retained as long as possible. It is also important that the time at which TBN
and TAN
levels cross is as long as possible. Both of these measures ensure a longer
oil life and
better engine protection over a greater period of time.
Beaker tests were performed on three lubricating oil compositions: a reference
oil,
Example 1 and Example 2. The reference oil included 2.475 wt% of an overbased
calcium
sulphonate detergent having a TBN of 425 mgKOH/g in base oil. Example 1
included
2.475 wt% of an overbased calcium sulphonate detergent having a TBN of 425
mgKOH/g
and 1.369 wt% of poly{[2-hydroxy-5-(tetrapropeny1)-1,3-phenylene]methylenel in
base
oil. Example 2 included 2.475 wt% of an overbased calcium sulphonate detergent
having
a TBN of 425 mgKOH/g and 1.369 wt% of poly{12-hydroxyethoxy-5-(tetrapropeny1)-
1,3-
phenylenelmethylene} in base oil. All three lubricating oil compositions had a
TBN of
10.5 mgKOH/g (ASTM D2896).
The poly{[2-hydroxy-5-(tetrapropeny1)-1,3-phenylenelmethylene I was prepared
as
follows:-
CA 02799378 2012-12-20
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Para-tetrapropenylphenol (known as TPP') (1 mole equivalent, commerically
available), alkylbenzene sulphonic acid (0.0033 mole% to TPP) and toluene
(30mass% to
TPP) were charged to a baffled reactor equipped with an overhead stirrer and a
Dean and
Stark reflux apparatus. A nitrogen blanket was used throughout. Stirring was
increased to
160-170 rpm and the temperature was ramped up to 110 C over 40 mins. 36.5%
formaldehyde solution (1.18 equiv. moles of formaldehyde to TPP used) was
charged over
2 hrs at a constant rate. The temperature was maintained at 110 C throughout
the
addition. On completion of formaldehyde addition, the temperature was
increased up to
120 C and maintained for 1 hr to remove the remaining water. The reaction was
cooled to
.. 90 C, then 50% sodium hydroxide solution (1.25 moles equiv to alkylbenzene
sulphonic
acid) was charged over 0.5 hrs. The temperature was ramped up to 130 C over
0.5 hrs and
maintained for a further 1 hr to remove water. With apparatus set-up for
distillation, the
intermediate was heated up to 130 C over 1 hr under vacuum to remove the
toluene.
Mineral oil was used to cutback product to 50% active ingredient.
The poly {[2-hydroxyethoxy-5-(tetrapropeny1)-1,3-phenylene]methylenel was
prepared as follows:-
Para-tetrapropenylphenol (known as `TPP') (1 mole equivalent, commerically
available), alkylbenzene sulphonic acid (0.0033 mole% to TPP) and toluene
(30mass% to
TPP) were charged to a baffled reactor equipped with an overhead stirrer and a
Dean and
Stark reflux apparatus. A nitrogen blanket was used throughout. The stirring
rate was
increased to 160-170 rpm. The temperature was ramped up to 110 C over 40 mins.
36.5% formaldehyde solution (1.18 equiv. moles of folinaldehyde to TPP used)
was
charged over 2 hrs at a constant rate. The temperature was maintained at 110 C
throughout the addition. On completion of formaldehyde addition, the
temperature was
increased up to 120 C and maintained for 1 hr to remove the remaining water.
The
reaction was cooled to 90 C, then 50% sodium hydroxide solution (2.22 mass% to
TPP)
was charged over 0.5 hrs. The temperature was ramped up to 130 C over 0.5 hrs
and
maintained for a further 1 hr to remove water. With apparatus set-up for
distillation, the
intermediate was heated up to 130 C over 1 hr under vacuum to remove the
toluene.
Xylene (30mass% to TPP) was charged whilst cooling down to 90 C. The Dean and
Stark
apparatus was switched from distillation to reflux. Ethylene carbonate (1.02
equivalent
CA 02799378 2012-12-20
- 25 -
moles to TPP) was charged over 0.5 hrs using a dropping funnel. The
temperature was
ramped up to reflux point at 165 C over 1 hr. IR analysis was used to
determine when
ethylene carbonate was fully consumed (typically after 2.5 firs). The
temperature was
maintained at 165 C and vacuum distillation was used to remove xylene. Mineral
oil was
used to cutback product to 50% active ingredient.
The Beaker test involved titrating the oil formulation with 1.0M sulphuric
acid,
and analyzing the TAN and TBN. The flow rate of acid was 10 ml/hr, the
quantity of oil
was 250g, the stirring rate was 300rpm and the oil temperature was 95 C.
After each sample was tested, a centrifuge step was used to remove insoluble
Di solids before oil analysis.
The results are as follows:
Reference Oil
Acid Titration TAN ASTM D664 TBN ASTM D 4739 TBN (04739) -
time /h TAN (D664)
0 0.44 8.8 8.38
0.25 1.73 5.3 3.57
0.5 1.58 4.7 3.12
1 1.56 4.4 2.84
1.5 1.77 4.0 2.23
2.5 1.63 1.6 -0.03
Example 1
Acid Titration TAN ASTM D664 TBN ASTM D 4739 TBN (D4739) -
time /h TAN (D664)
0 0.71 6.7 5.97
0.25 1.20 6.1 4.9
0.5 1.22 5.1 3.9
1 1.27 4.8 3.5
1.5 1.33 4.0 2.7
2.5 1.30 3.9 2.6
CA 02799378 2012-12-20
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Example 2
Acid Titration TAN ASTM 0664 TBN ASTM D 4739 TBN (D4739) -
time /h TAN (0664)
0 0.40 8.2 7.8
0.25 0.70 5.7 5.00
0.5 0.96 5.5 4.54
1 0.89 5.4 4.51
1.5 0.95 4.4 3.45
2.5 0.97 3.3 2.33
The results are also shown in Figure 1.
The results show that the reference oil reaches TAN and TBN crossover much
earlier than Examples 1 and 2. Therefore, the base in the reference oil is
depleted much
sooner than the base in Examples 1 and 2. In fact, Examples 1 and 2 did not
show TAN
and TBN crossover even at the end of the test at 2.5 hours. Once lubricating
oil
compositions exhibit TAN and TBN crossover, the composition has insufficient
base
levels to neutralize any acid produced by an engine, which causes engine wear.
These
results are surprising as Examples 1 and 2 do not include any more base than
the reference
oil at the start of the test (i.e. all examples started the Beaker Test with a
TBN of 10.5
mgKOH/g).
