U.S. patent application number 11/527309 was filed with the patent office on 2007-04-26 for antiwear inhibiting and load enhancing additive combinations for lubricating oils.
Invention is credited to Jacob J. Habeeb, Douglas E. Johnson.
Application Number | 20070093395 11/527309 |
Document ID | / |
Family ID | 37671074 |
Filed Date | 2007-04-26 |
United States Patent
Application |
20070093395 |
Kind Code |
A1 |
Habeeb; Jacob J. ; et
al. |
April 26, 2007 |
Antiwear inhibiting and load enhancing additive combinations for
lubricating oils
Abstract
The anti-wear and load carrying properties of lubricating oils
is enhanced by the addition of the combination of thiosalicylic
acid and adenine. Phosphate ester anti-wear and load carrying
additives may be employed with the combination of thiosalicylic
acid and adenine.
Inventors: |
Habeeb; Jacob J.;
(Westfield, NJ) ; Johnson; Douglas E.; (Cherry
Hill, NJ) |
Correspondence
Address: |
ExxonMobil Research and Engineering Company
P. O. Box 900
Annandale
NJ
08801-0900
US
|
Family ID: |
37671074 |
Appl. No.: |
11/527309 |
Filed: |
September 26, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60728833 |
Oct 21, 2005 |
|
|
|
Current U.S.
Class: |
508/256 |
Current CPC
Class: |
C10N 2030/12 20130101;
C10M 2223/0405 20130101; C10N 2030/06 20130101; C10N 2030/10
20130101; C10M 141/10 20130101; C10M 2215/223 20130101; C10M 141/08
20130101; C10M 2205/173 20130101; C10M 2219/086 20130101 |
Class at
Publication: |
508/256 |
International
Class: |
C10L 1/22 20060101
C10L001/22 |
Claims
1. A lubricating composition comprising: (a) a major amount of an
oil of lubricating viscosity, and (b) an effective amount of an
additive combination comprising thiosalicylic acid and adenine.
2. The composition of claim 1 wherein the weight ratio of
thiosalicylic acid to adenine is in the range of about 5:1 to about
50:1.
3. The composition of claim 2 wherein the combined thiosalicylic
acid and adenine comprises about 0.01 wt % to about 1.0 wt % based
on the total weight of composition.
4. The composition of claim 2 wherein the lubricating composition
includes a phosphate ester anti-wear and load carrying
additive.
5. The composition of claim 4 wherein the anti-wear and load
carrying additive is tricresyl phosphate.
6. The composition of claim 4 wherein the anti-wear and load
carrying additive is a phosphate oligomer.
7. The composition of claim 3 wherein the additive combination and
phosphate ester additive comprises from about 0.1 to about 5.0 wt %
of the total lubricating composition.
8. The composition of claim 5 wherein the weigh ratio of the
combined thiosalicylic acid and adenine to tricresyl phosphate is
in the range of about 1:1 to about 1:50.
9. The composition of claims 1 and 5 wherein the oil of lubricating
viscosity is a gas to liquid base oil.
10. The composition of claims 1 and 6 wherein the oil of
lubricating viscosity is an ester base oil.
11. A lubricating oil additive combination comprising thiosalicylic
acid and adenine in the weight ratio of about 50:1 to about
5:1.
12. The additive of claim 11 including an anti-wear and load
carrying phosphate ester additive wherein the weight ratio of the
combined thiosalicylic acid and adenine to phosphate ester additive
is in the range of about 1:1 to about 1:50.
13. The additive of claim 12 wherein the phosphate ester is
tricresyl phosphate.
14. The additive of claim 12 wherein the phosphate ester is a
phosphate oligomer.
15. A method for enhancing the antiwear and load carrying
performance of a lubricating oil comprising adding from about 0.5
to about 15 wt % of an additive of any one of claims 12 to 14.
Description
[0001] This application claims the benefit of U.S. Provisional
application 60/728,833 filed Oct. 21, 2005.
FIELD OF INVENTION
[0002] The present invention relates to antiwear inhibiting and
load carrying enhancing additives. More particularly the present
invention relates to lubricating oils containing a combination of
additives that provide performance enhancements of lubricating
oils.
BACKGROUND OF THE INVENTION
[0003] The art of lubricating oil formulation has become
increasingly complex with ever more stringent industry standards
dictated by the increasing complexity of the mechanical equipment
requiring lubrication. One important requirement for lubricants is
to provide load carrying capability. At the same time the lubricant
formulation should provide other important properties. For example,
the formulation should provide resistance to oxidation in order to
achieve operation life of adequate length. Experience has shown,
however, that the incorporation of one type of additive in a
lubricant composition can have a negative impact on the function of
another type of additive in that composition. Indeed, the presence
of antiwear additives in lubricants often reduces the oxidation
stability compared to a similar oil where the antiwear additive is
absent. The result, of course, is that extensive research is
required in developing new lubricant formulations that have
enhanced performance.
SUMMARY OF THE INVENTION
[0004] It has now been established that the combination of
thiosalicylic acid and adenine provide a lubricant base stock with
enhanced antiwear and load carrying properties when used in
effective amounts. Thus in one embodiment there is provided a
lubricating composition comprising: [0005] (a) a major amount of an
oil of lubricating viscosity, and [0006] (b) an effective amount of
an additive combination comprising thiosalicylic acid and
adenine.
[0007] Other embodiments of the invention will become apparent from
the detailed description that follows:
DETAILED DESCRIPTION OF THE INVENTION
[0008] A wide range of lubricating base oils is known in the art.
Lubricating base oils that are useful in the present invention are
natural oils, synthetic oils, and unconventional oils. Natural oil,
synthetic oils, and unconventional oils and mixtures thereof can be
used unrefined, refined, or rerefined (the latter is also known as
reclaimed or reprocessed oil). Unrefined oils are those obtained
directly from a natural, synthetic or unconventional source and
used without further purification. These include for example shale
oil obtained directly from retorting operations, petroleum oil
obtained directly from primary distillation, and ester oil obtained
directly from an esterification process. Refined oils are similar
to the oils discussed for unrefined oils except refined oils are
subjected to one or more purification or transformation steps to
improve at least one lubricating oil property. One skilled in the
art is familiar with many purification or transformation processes.
These processes include, for example, solvent extraction, secondary
distillation, acid extraction, base extraction, filtration,
percolation, hydrogenation, hydrorefining, and hydrofinishing.
Rerefined oils are obtained by processes analogous to refined oils,
but use an oil that has been previously used.
[0009] Groups I, II, III, IV and V are broad categories of base oil
stocks developed and defined by the American Petroleum Institute
(API Publication 1509; www.API.org) to create guidelines for
lubricant base oils. Group I base stocks generally have a viscosity
index of between about 80 to 120 and contain greater than about
0.03% sulfur and less than about 90% saturates. Group II base
stocks generally have a viscosity index of between about 80 to 120,
and contain less than or equal to about 0.03% sulfur and greater
than or equal to about 90% saturates. Group III stock generally has
a viscosity index greater than about 120 and contains less than or
equal to about 0.03% sulfur and greater than about 90% saturates.
Group IV includes polyalphaolefins (PAO). Group V base stocks
include base stocks not included in Groups I-IV. Table A summarizes
properties of each of these five groups. TABLE-US-00001 TABLE A
Base Stock Properties Saturates Sulfur Viscosity Index Group I
<90% and/or >0.03% and .gtoreq.80 and <120 Group II
.gtoreq.90% and .ltoreq.0.03% and .gtoreq.80 and <120 Group III
.gtoreq.90% and .ltoreq.0.03% and .gtoreq.120 Group IV
Polyalphaolefins (PAO) Group V All other base oil stocks not
included in Groups I, II, III, or IV
[0010] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source, for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful in the present
invention. Natural oils vary also as to the method used for their
production and purification, for example, their distillation range
and whether they are straight run or cracked, hydrorefined, or
solvent extracted.
[0011] Synthetic oils include hydrocarbon oils as well as non
hydrocarbon oils. Synthetic oils can be derived from processes such
as chemical combination (for example, polymerization,
oligomerization, condensation, alkylation, acylation, etc.), where
materials consisting of smaller, simpler molecular species are
built up (i.e., synthesized) into materials consisting of larger,
more complex molecular species. Synthetic oils include hydrocarbon
oils such as polymerized and interpolymerized olefins
(polybutylenes, polypropylenes, propylene isobutylene copolymers,
ethylene-olefin copolymers, and ethylene-alphaolefin copolymers,
for example). Polyalphaolefin (PAO) oil base stock is a commonly
used synthetic hydrocarbon oil. By way of example, PAOs derived
from C.sub.8, C.sub.10, C.sub.12, C.sub.14 olefins or mixtures
thereof may be utilized. See U.S. Pat. Nos. 4,956,122; 4,827,064;
and U.S. Pat. No. 4,827,073, which are incorporated herein by
reference in their entirety.
[0012] The number average molecular weights of the PAOs, which are
known materials and generally available on a major commercial scale
from suppliers such as ExxonMobil Chemical Company, Chevron,
BP-Amoco, and others, typically vary from about 250 to about 3000,
or higher, and PAOs may be made in viscosities up to about 100 cSt
(100.degree. C.), or higher. In addition, higher viscosity PAOs are
commercially available, and may be made in viscosities up to about
3000 cSt (100.degree. C.), or higher. The PAOs are typically
comprised of relatively low molecular weight hydrogenated polymers
or oligomers of alphaolefins which include, but are not limited to,
about C.sub.2 to about C.sub.32 alphaolefins with about C.sub.8 to
about C.sub.16 alphaolefins, such as 1-octene, 1-decene, 1-dodecene
and the like, being preferred. The preferred polyalphaolefins are
poly-1-octene, poly-1-decene and poly-1-dodecene and mixtures
thereof and mixed olefin-derived polyolefins. However, the dimers
of higher olefins in the range of about C.sub.14 to C.sub.18 may be
used to provide low viscosity base stocks of acceptably low
volatility. Depending on the viscosity grade and the starting
oligomer, the PAOs may be predominantly trimers and tetramers of
the starting olefins, with minor amounts of the higher oligomers,
having a viscosity range of about 1.5 to 12 cSt.
[0013] PAO fluids may be conveniently made by the polymerization of
an alphaolefin in the presence of a polymerization catalyst such as
the Friedel-Crafts catalysts including, for example, aluminum
trichloride, boron trifluoride or complexes of boron trifluoride
with water, alcohols such as ethanol, propanol or butanol,
carboxylic acids or esters such as ethyl acetate or ethyl
propionate. For example the methods disclosed by U.S. Pat. No.
4,149,178 or U.S. Pat. No. 3,382,291 may be conveniently used
herein. Other descriptions of PAO synthesis are found in the
following U.S. Pat. Nos. 3,742,082; 3,769,363; 3,876,720;
4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355; 4,956,122;
and U.S. Pat. No. 5,068,487. All of the aforementioned patents are
incorporated herein by reference in their entirety. The dimers of
the C.sub.14 to C.sub.18 olefins are described in U.S. Pat. No.
4,218,330, also incorporated herein.
[0014] Other useful synthetic lubricating base stock oils such as
silicon-based oil or esters of phosphorus containing acids may also
be utilized. For examples of other synthetic lubricating base
stocks are the seminal work "Synthetic Lubricants", Gunderson and
Hart, Reinhold Publ. Corp., N.Y. 1962, which is incorporated in its
entirety.
[0015] In alkylated aromatic stocks, the alkyl substituents are
typically alkyl groups of about 8 to 25 carbon atoms, usually from
about 10 to 18 carbon atoms and up to about three such substituents
may be present, as described for the alkyl benzenes in ACS
Petroleum Chemistry Preprint 1053-1058, "Poly n-Alkylbenzene
Compounds: A Class of Thermally Stable and Wide Liquid Range
Fluids", Eapen et al, Philadelphia 1984. Tri-alkyl benzenes may be
produced by the cyclodimerization of 1-alkynes of 8 to 12 carbon
atoms as described in U.S. Pat. No. 5,055,626. Other alkylbenzenes
are described in European Patent Application 168 534 and U.S. Pat.
No. 4,658,072. Alkylbenzenes are used as lubricant basestocks,
especially for low-temperature applications (arctic vehicle service
and refrigeration oils) and in papermaking oils. They are
commercially available from producers of linear alkylbenzenes
(LABs) such as Vista Chem. Co., Huntsman Chemical Co., Chevron
Chemical Co., and Nippon Oil Co. Linear alkylbenzenes typically
have good low pour points and low temperature viscosities and VI
values greater than about 100, together with good solvency for
additives. Other alkylated aromatics which may be used when
desirable are described, for example, in "Synthetic Lubricants and
High Performance Functional Fluids", Dressler, H., chap 5, (R. L.
Shubkin (E. d.)), Marcel Dekker, N.Y., 1993. Each of the
aforementioned references is incorporated herein by reference in
its entirety.
[0016] Alkylene oxide polymers and interpolymers and their
derivatives containing modified terminal hydroxyl groups obtained
by, for example, esterification or etherification are useful
synthetic lubricating oils. By way of example, these oils may be
obtained by polymerization of ethylene oxide or propylene oxide,
the alkyl and aryl ethers of these polyoxyalkylene polymers
(methyl-polyisopropylene glycol ether having an average molecular
weight of about 1000, diphenyl ether of polyethylene glycol having
a molecular weight of about 500-1000, and the diethyl ether of
polypropylene glycol having a molecular weight of about 1000 to
1500, for example) or mono- and poly-carboxylic esters thereof (the
acidic acid esters, mixed C.sub.3-8 fatty acid esters, or the
C.sub.13 Oxo acid diester of tetraethylene glycol, for
example).
[0017] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of monocarboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl) sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl
sebacate, etc.
[0018] Particularly useful synthetic esters are those full or
partial esters which are obtained by reacting one or more
polyhydric alcohols (preferably the hindered polyols such as the
neopentyl polyols, e.g., neopentyl glycol, trimethylol ethane,
2-methyl-2-propyl-1,3-propanediol, trimethylol propane,
pentaerythritol and dipentaerythritol) with alkanoic acids
containing at least about 4 carbon atoms (preferably C.sub.5 to
C.sub.30 acids such as saturated straight chain fatty acids
including caprylic acid, capric acid, lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid).
[0019] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipenta-erythritol with one or more
monocarboxylic acids containing from about 5 to about 10 carbon
atoms.
[0020] Silicon-based oils are another class of useful synthetic
lubricating oils. These oils include polyalkyl-, polyaryl-,
polyalkoxy-, and polyaryloxy-siloxane oils and silicate oils.
Examples of suitable silicon-based oils include tetraethyl
silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl)asilicate,
tetra-(4-methylhexyl) silicate, tetra-(p-tert-butylphenyl)
silicate, hexyl-(4-methyl-2-pentoxy) disiloxane, poly(methyl)
siloxanes, and poly-(methyl-2-methylphenyl) siloxanes.
[0021] Another class of synthetic lubricating oil is esters of
phosphorous-containing acids. These include, for example, tricresyl
phosphate, trioctyl phosphate, diethyl ester of decanephosphonic
acid.
[0022] Another class of oils includes polymeric tetrahydrofurans,
their derivatives, and the like.
[0023] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0024] Other useful lubricant fluids include Gas-to-Liquids (GTL)
materials, preferably GTL base stocks and base oils. GTL materials
are materials that are derived via one or more synthesis,
combination, transformation, rearrangement, and/or deconstructive
processes from simple gaseous carbon-containing and
hydrocarbon-containing compounds and elements as feedstocks. GTL
base stocks and base oils are fluids of lubricating viscosity that
are generally derived from hydrocarbons, for example waxy
synthesized hydrocarbons, that are further derived from simpler
gaseous carbon-containing and hydrocarbon-containing compounds and
elements as feedstocks. GTL base stocks and base oils include, for
example, synthesized wax isomerate base stocks and base oils,
comprising for example, hydroisomerized or isodewaxed synthesized
waxy stocks, hydroisomerized or isodewaxed Fischer-Tropsch (F-T)
hydrocarbons, preferably hydroisomerized or isodewaxed F-T waxy
hydrocarbons or hydroisomerized or isodewaxed F-T waxes,
hydroisomerized synthesized waxes or mixtures thereof.
[0025] Other useful lubricant fluids include Gas-to-Liquids (GTL)
materials, preferably GTL base stocks and base oils. GTL materials
are materials that are derived via one or more synthesis,
combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds, and/or elements as
feedstocks such as hydrogen, carbon dioxide, carbon monoxide,
water, methane, ethane, ethylene, acetylene, propane, propylene,
propyne, butane, butylenes, and butynes. GTL base stocks and base
oils are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons, for example waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feedstocks. GTL base stocks and base oils include wax
isomerates, comprising, for example, hydroisomerized or isodewaxed
synthesized waxy hydrocarbons, hydroisomerized or isodewaxed
Fischer-Tropsch (F-T) material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates), preferably
hydroisomerized or isodewaxed F-T waxy hydrocarbons or
hydroisomerized or isodewaxed F-T waxes, hydroisomerized or
isodewaxed synthesized waxes, or mixtures thereof. The term GTL
base stocks and base oil further encompass the aforesaid base stock
and base oils in combination with other hydroisomerized or
isodewaxed materials comprising for example, hydroisomerized or
isodewaxed mineral/petroleum-derived hydrocarbons, hydroisomerized
or isodewaxed waxy hydrocarbons, or mixtures thereof, derived from
different feed materials including, for example, waxy distillates
such as gas oils, waxy hydrocracked hydrocarbons, lubricating oils,
high pour point polyalphaolefins, foots oil, normal alpha olefin
waxes, slack waxes, deoiled waxes, and microcrystalline waxes.
[0026] GTL base stocks and base oils derived from GTL materials,
especially, hydroisomerized/isodewaxed F-T material derived base
stocks and base oils, and other hydroisomerized/isodewaxed wax
derived base stocks and base oils, such as wax isomerates are
characterized typically as having kinematic viscosities at
100.degree. C. of from about 2 cSt to about 50 cSt, preferably from
about 3 cSt to about 30 cSt, more preferably from about 3.5 cSt to
about 25 cSt, as exemplified by a GTL base stock derived by the
isodewaxing of F-T wax, which has a kinematic viscosity of about 4
cSt at 100.degree. C. and a viscosity index of about 130 or
greater. Reference herein to Kinematic viscosity refers to a
measurement made by ASTM method D445.
[0027] GTL base stocks and base oils derived from GTL materials,
especially hydroisomerized/isodewaxed F-T material derived base
stocks and base oils, and other hydroisomerized/isodewaxed
wax-derived base stocks and base oils, such as wax
hydroisomerates/isodewaxates, which are components of this
invention are further characterized typically as having pour points
of about -5.degree. C. or lower, preferably about -10.degree. C. or
lower, more preferably about -15.degree. C. or lower, still more
preferably about -20.degree. C. or lower, and under some conditions
may have advantageous pour points of about -25.degree. C. or lower,
with useful pour points of about -30.degree. C. to about
-40.degree. C. or lower. If necessary, a separate dewaxing step may
be practiced to achieve the desired pour point. References herein
to pour point refer to measurement made by ASTM D97 and similar
automated versions.
[0028] The GTL base stocks and base oils derived from GTL
materials, especially hydroisomerized/isodewaxed F-T material
derived base stocks and base oils, and other
hydroisomerized/isodewaxed wax-derived base stocks and base oils,
such as wax isomerate/isodewaxate which are components of this
invention are also characterized typically as having viscosity
indices of 80 or greater, preferably 100 or greater, and more
preferably 120 or greater. Additionally, in certain particular
instances, viscosity index of these base stocks may be preferably
130 or greater, more preferably 135 or greater, and even more
preferably 140 or greater. For example, GTL base stocks and base
oils that derived from GTL materials preferably F-T materials
especially F-T wax generally have a viscosity index of 130 or
greater. References herein to viscosity index refer to ASTM method
D2270.
[0029] In addition, the GTL base stocks and base oils are typically
highly paraffinic (>90% saturates), and may contain mixtures of
monocycloparaffins and multicycloparaffms in combination with
non-cyclic isoparaffms. The ratio of the naphthenic (i.e.,
cycloparaffin) content in such combinations varies with the
catalyst and temperature used. Further, GTL base stocks and base
oils typically have very low sulfur and nitrogen content, generally
containing less than about 10 ppm, and more typically less than
about 5 ppm of each of these elements. The sulfur and nitrogen
content of GTL base stock and base oil obtained by the
hydroisomerization/isodewaxing of F-T material, especially F-T wax
is essentially nil.
[0030] Useful compositions of GTL base stocks and base oils,
hydroisomerized or isodewaxed F-T material derived base stocks and
base oils, and wax-derived hydroisomerized/isodewaxed base stocks
and base oils, such as wax isomerates/isodewates, are recited in
U.S. Pat. Nos. 6,080,301; 6,090,989, and U.S. Pat. No. 6,165,949
for example.
[0031] Wax isomerate/isodewaxate base stocks and base oils derived
from waxy feeds which are also suitable for use in this invention,
are paraffinic fluids of lubricating viscosity derived from
hydroisomerized or isodewaxed waxy feedstocks of mineral or natural
source origin, e.g., feedstocks such as one or more of gas oils,
slack wax, waxy fuels hydrocracker bottoms, hydrocarbon raffinates,
natural waxes, hyrocrackates, thermal crackates or other suitable
mineral or non-mineral oil derived waxy materials, linear or
branched hydrocarbyl compounds with carbon number of about 20 or
greater, preferably about 30 or greater, and mixtures of such
isomerate/isodewaxate base stocks and base oils.
[0032] As used herein, the following terms have the indicated
meanings: [0033] "paraffinic" material: any saturated hydrocarbons,
such as alkanes. Paraffinic materials may include linear alkanes,
branched alkanes (iso-paraffins), cycloalkanes (cycloparaffins;
mono-ring and/or multi-ring), and branched cycloalkanes; [0034]
"hydroprocessing": a refining process in which a feedstock is
heated with hydrogen at high temperature and under pressure,
commonly in the presence of a catalyst, to remove and/or convert
less desirable components and to produce an improved product;
[0035] "hydrotreating": a catalytic hydrogenation process that
converts sulfur- and/or nitrogen-containing hydrocarbons into
hydrocarbon products with reduced sulfur and/or nitrogen content,
and which generates hydrogen sulfide and/or ammonia (respectively)
as byproducts; similarly, oxygen containing hydrocarbons can also
be reduced to hydrocarbons and water; [0036] "hydrodewaxing" (or
catalytic dewaxing): a catalytic process in which normal paraffins
(wax) and/or waxy hydrocarbons are converted by
cracking/fragmentation into lower molecular weight species, and/or
by rearrangement/isomerization into more branched iso-paraffins;
[0037] "hydroisomerization" (or isodewaxing): a catalytic process
in which normal paraffins (wax) and/or slightly branched
iso-paraffins are converted by rearrangement/isomerization into
more branched iso-paraffins; [0038] "hydrocracking": a catalytic
process in which hydrogenation accompanies the
cracking/fragmentation of hydrocarbons, e.g., converting heavier
hydrocarbons into lighter hydrocarbons, or converting aromatics
and/or cycloparaffins (naphthenes) into non-cyclic branched
paraffins.
[0039] As previously indicated, wax isomerate base stock and base
oils suitable for use as the necessary components in the present
invention, can be derived from other waxy feeds such as slack
wax.
[0040] Slack wax is the wax recovered from petroleum oils by
solvent or autorefrigerative dewaxing. Solvent dewaxing employs
chilled solvent such as methyl ethyl ketone (MEK), methyl isobutyl
ketone (MIBK), mixtures of MEK/MIBK, mixtures of MEK and toluene,
while autorefrigerative dewaxing employs pressurized, liquefied low
boiling hydrocarbons such as propane or butane.
[0041] Slack waxes, being secured from petroleum oils, may contain
sulfur and nitrogen containing compounds. Such heteroatom compounds
must be removed by hydrotreating (and not hydrocracking), as for
example by hydrodesulfurization (HDS) and hydrodenitrogenation
(HDN) so as to avoid subsequent poisoning/deactivation of the
hydroisomerization catalyst.
[0042] In a preferred embodiment, the GTL material is a F-T
material (i.e., hydrocarbons, waxy hydrocarbons, wax). A slurry F-T
synthesis process may be beneficially used for synthesizing the
feed from CO and hydrogen and particularly one employing a F-T
catalyst comprising a catalytic cobalt component to provide a high
alpha for producing the more desirable higher molecular weight
paraffins. This process is also well known to those skilled in the
art.
[0043] In a F-T synthesis process, a synthesis gas comprising a
mixture of H.sub.2 and CO is catalytically converted into
hydrocarbons and preferably liquid hydrocarbons. The mole ratio of
the hydrogen to the carbon monoxide may broadly range from about
0.5 to 4, but which is more typically within the range of from
about 0.7 to 2.75 and preferably from about 0.7 to 2.5. As is well
known, F-T synthesis processes include processes in which the
catalyst is in the form of a fixed bed, a fluidized bed or as a
slurry of catalyst particles in a hydrocarbon slurry liquid. The
stoichiometric mole ratio for a F-T synthesis reaction is 2.0, but
there are many reasons for using other than a stoichiometric ratio
as those skilled in the art know. In a cobalt slurry hydrocarbon
synthesis process the feed mole ratio of the H.sub.2 to CO is
typically about 2.1/1. The synthesis gas comprising a mixture of
H.sub.2 and CO is bubbled up into the bottom of the slurry and
reacts in the presence of the particulate F-T synthesis catalyst in
the slurry liquid at conditions effective to form hydrocarbons, a
portion of which are liquid at the reaction conditions and which
comprise the hydrocarbon slurry liquid. The synthesized hydrocarbon
liquid is separated from the catalyst particles as filtrate by
means such as filtration, although other separation means such as
centrifugation can be used. Some of the synthesized hydrocarbons
pass out the top of the hydrocarbon synthesis reactor as vapor,
along with unreacted synthesis gas and other gaseous reaction
products. Some of these overhead hydrocarbon vapors are typically
condensed to liquid and combined with the hydrocarbon liquid
filtrate. Thus, the initial boiling point of the filtrate may vary
depending on whether or not some of the condensed hydrocarbon
vapors have been combined with it. Slurry hydrocarbon synthesis
process conditions vary somewhat depending on the catalyst and
desired products. Typical conditions effective to form hydrocarbons
comprising mostly C.sub.5+paraffins, (eg., C.sub.5+-C.sub.200) and
preferably C.sub.10+paraffins, in a slurry hydrocarbon synthesis
process employing a catalyst comprising a supported cobalt
component include, for example, temperatures, pressures and hourly
gas space velocities in the range of from about 320-850.degree. F.,
80-600 psi and 100-40,000 V/hr/V, expressed as standard volumes of
the gaseous CO and H.sub.2 mixture (0.degree. C., 1 atm) per hour
per volume of catalyst, respectively. It is preferred that the
hydrocarbon synthesis reaction be conducted under conditions in
which limited or no water gas shift reaction occurs and more
preferably with no water gas shift reaction occurring during the
hydrocarbon synthesis. It is also preferred to conduct the reaction
under conditions to achieve an alpha of at least 0.85, preferably
at least 0.9 and more preferably at least 0.92, so as to synthesize
more of the more desirable higher molecular weight hydrocarbons.
This has been achieved in a slurry process using a catalyst
containing a catalytic cobalt component. Those skilled in the art
know that by alpha is meant the Schultz-Flory kinetic alpha. While
suitable F-T reaction types of catalyst comprise, for example, one
or more Group VIII catalytic metals such as Fe, Ni, Co, Ru and Re,
it is preferred that the catalyst comprise a cobalt catalytic
component. In one embodiment the catalyst comprises catalytically
effective amounts of Co and one or more of Re, Ru, Fe, Ni, Th, Zr,
Hf, U, Mg and La on a suitable inorganic support material,
preferably one which comprises one or more refractory metal oxides.
Preferred supports for Co containing catalysts comprise titania,
particularly. Useful catalysts and their preparation are known and
illustrative, but nonlimiting examples may be found, for example,
in U.S. Pat. Nos. 4,568,663; 4,663,305; 4,542,122; 4,621,072 and
U.S. Pat. No. 5,545,674.
[0044] As set forth above, the waxy feed from which a preferred
base stock is derived comprises mineral wax or other natural source
wax, especially slack wax, or waxy F-T material, referred to as F-T
wax. F-T wax preferably has an initial boiling point in the range
of from 650-750.degree. F. and preferably continuously boils up to
an end point of at least 1050.degree. F. A narrower cut waxy feed
may also be used during the hydroisomerization. A portion of the
n-paraffin waxy feed is converted to lower boiling isoparaffinic
material. Hence, there must be sufficient heavy n-paraffin material
to yield an isoparaffin containing isomerate boiling in the lube
oil range. If catalytic dewaxing is also practiced, some of the
isomerate will also be converted to lower boiling material during
the dewaxing. Hence, it is preferred that the end boiling point of
the waxy feed be above 1050.degree. F. (1050.degree. F.+).
[0045] The waxy feed preferably comprises the entire
650-750.degree. F.+fraction formed by the hydrocarbon synthesis
process, with the initial cut point between 650.degree. F. and
750.degree. F. being determined by the practitioner and the end
point, preferably above 1050.degree. F., determined by the catalyst
and process variables employed by the practitioner for the
synthesis. Waxy feeds may be processed as the entire fraction or as
subsets of the entire fraction prepared by distillation or other
separation techniques. The waxy feed also typically comprises more
than 90%, generally more than 95% and preferably more than 98 wt %
paraffinic hydrocarbons, most of which are normal paraffins. It has
negligible amounts of sulfur and nitrogen compounds (e.g., less
than 1 wppm of each), with less than 2,000 wppm, preferably less
than 1,000 wppm and more preferably less than 500 wppm of oxygen,
in the form of oxygenates. Waxy feeds having these properties and
useful in the process of the invention have been made using a
slurry F-T process with a catalyst having a catalytic cobalt
component, as previously indicated.
[0046] The process of making the lubricant oil base stocks from
waxy stocks, e.g., slack wax or F-T wax, may be characterized as a
hydrodewaxing process. If slack waxes are used as the feed, they
may need to be subjected to a preliminary hydrotreating step under
conditions already well known to those skilled in the art to reduce
(to levels that would effectively avoid catalyst poisoning or
deactivation) or to remove sulfur- and nitrogen-containing
compounds which would otherwise deactivate the
hydroisomerization/hydrodewaxing catalyst used in subsequent steps.
If F-T waxes are used, such preliminary treatment is not required
because, as indicated above, such waxes have only trace amounts
(less than about 10 ppm, or more typically less than about 5 ppm to
nil) of sulfur or nitrogen compound content. However, some
hydrodewaxing catalyst fed F-T waxes may benefit from removal of
oxygenates while others may benefit from oxygenates treatment. The
hydrodewaxing process may be conducted over a combination of
catalysts, or over a single catalyst. Conversion temperatures range
from about 150.degree. C. to about 500.degree. C. at pressures
ranging from about 500 to 20,000 kPa. This process may be operated
in the presence of hydrogen, and hydrogen partial pressures range
from about 600 to 6000 kPa. The ratio of hydrogen to the
hydrocarbon feedstock (hydrogen circulation rate) typically range
from about 10 to 3500 n.1.1..sup.-1 (56 to 19,660 SCF/bb1) and the
space velocity of the feedstock typically ranges from about 0.1 to
20 LHSV, preferably 0.1 to 10 LHSV.
[0047] Following any needed hydridenitrogenation or
hydrodesulfurization, the hydroprocessing used for the production
of base stocks from such waxy feeds may use an amorphous
hydrocracking/hydroisomerization catalyst, such as a lube
hydrocracking (LHDC) catalysts, for example catalysts containing
Co, Mo, Ni, W, Mo, etc., on oxide supports, e.g., alumina, silica,
silica/alumina, or a crystalline hydrocracking/hydroisomerization
catalyst, preferably a zeolitic catalyst.
[0048] Other isomerization catalysts and processes for
hydrocracking/hydroisomerized/isodewaxing GTL materials and/or waxy
materials to base stock or base oil are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,900,407; 4,937,399; 4,975,177;
4,921,594; 5,059,299; 5,200,382; 5,516,740; 5,182,248; 5,290,426;
5,580,442; 5,976,351; 5,935,417; 5,885,438; 5,965,475; 6,190,532;
6,375,830; 6,332,974; 6,103,099; 6,025,305; 6,080,301; 6,096,940;
6,620,312; 6,676,827; 6,383,366; 6,475,960; 5,059,299; 5,977,425;
5,935,416; 4,923,588; 5,158,671; and U.S. Pat. No. 4,897,178; EP
0324528 (B1), EP 0532116 (B1), EP 0532118 (B1), EP 0537815 (B1), EP
0583836 (B2), EP 0666894 (B2), EP 0668342 (B1), EP 0776959 (A3), WO
97/031693 (A1), WO 02/064710 (A2), WO 02/064711 (A1), WO 02/070627
(A2), WO 02/070629 (A1), WO 03/033320 (A1) as well as in British
Patents 1,429,494; 1,350,257; 1,440,230; 1,390,359; WO 99/45085 and
WO 99/20720. Particularly favorable processes are described in
European Patent Applications 464546 and 464547. Processes using F-T
wax feeds are described in U.S. Pat. Nos. 4,594,172; 4,943,672;
6,046,940; 6,475,960; 6,103,099; 6,332,974; and 6,375,830.
[0049] Hydrocarbon conversion catalysts useful in the conversion of
the n-paraffin waxy feedstocks disclosed herein to form the
isoparaffinic hydrocarbon base oil are zeolite catalysts, such as
ZSM-5, ZSM-11, ZSM-23, ZSM-35, ZSM-12, ZSM-38, ZSM-48, offretite,
ferrierite, zeolite beta, zeolite theta, zeolite alpha, as
disclosed in U.S. Pat. No. 4,906,350. These catalysts are used in
combination with Group VIII metals, in particular palladium or
platinum. The Group VIII metals may be incorporated into the
zeolite catalysts by conventional techniques, such as ion
exchange.
[0050] In one embodiment, conversion of the waxy feedstock may be
conducted over a combination of Pt/zeolite beta and Pt/ZSM-23
catalysts in the presence of hydrogen. In another embodiment, the
process of producing the lubricant oil base stocks comprises
hydroisomerization and dewaxing over a single catalyst, such as
Pt/ZSM-35. In yet another embodiment, the way feed can be fed over
Group VIII metal loaded ZSM-48, preferably Group VIII noble metal
loaded ZSM-48, more preferably Pt/ZSM-48 in either one stage or two
stages. In any case, useful hydrocarbon base oil products may be
obtained. Catalyst ZSM-48 is described in U.S. Pat. No. 5,075,269,
the disclosure of which is incorporated herein by reference in its
entirety. The use of the Group VIII metal loaded ZSM-48 family of
catalysts in the isodewaxing of the waxy feedstock eliminates the
need for any subsequent, separate dewaxing step, and is
preferred.
[0051] A dewaxing step, when needed, may be accomplished using
either well known solvent or catalytic dewaxing processes and
either the entire hydroisomerate or the 650-750.degree. F.+fraction
may be dewaxed, depending on the intended use of the
650-750.degree. F.-material present, if it has not been separated
from the higher boiling material prior to the dewaxing. In solvent
dewaxing, the hydroisomerate may be contacted with chilled solvents
such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone
(MIBK), mixtures of MEK/MIBK, or mixtures of MEK/toluene and the
like, and further chilled to precipitate out the higher pour point
material as a waxy solid which is then separated from the
solvent-containing lube oil fraction which is the raffinate. The
raffinate is typically further chilled in scraped surface chillers
to remove more wax solids. Low molecular weight hydrocarbons, such
as propane, are also used for dewaxing, in which the hydroisomerate
is mixed with liquid propane, a least a portion of which is flashed
off to chill down the hydroisomerate to precipitate out the wax.
The wax is separated from the raffinate by filtration, membrane
separation or centrifugation. The solvent is then stripped out of
the raffinate, which is then fractionated to produce the preferred
base stocks useful in the present invention. Also well known is
catalytic dewaxing, in which the hydroisomerate is reacted with
hydrogen in the presence of a suitable dewaxing catalyst at
conditions effective to lower the pour point of the hydroisomerate.
Catalytic dewaxing also converts a portion of the hydroisomerate to
lower boiling materials, in the boiling range, for example,
650-750.degree. F.-, which are separated from the heavier
650-750.degree. F.+base stock fraction and the base stock fraction
fractionated into two or more base stocks. Separation of the lower
boiling material may be accomplished either prior to or during
fraction of the 650-750.degree. F.+material into the desired base
stocks.
[0052] Any dewaxing catalyst which will reduce the pour point of
the hydroisomerate and preferably those which provide a large yield
of lube oil base stock from the hydroisomerate may be used. These
include shape selective molecular sieves which, when combined with
at least one catalytic metal component, have been demonstrated as
useful for dewaxing petroleum oil fractions and include, for
example, ferrierite, mordenite, ZSM-5, ZSM-11, ZSM-23, ZSM-35,
ZSM-22 also known as theta one or TON, and the
silicoaluminophosphates known as SAPO's. A dewaxing catalyst which
has been found to be unexpectedly particularly effective comprises
a noble metal, preferably Pt, composited with H-mordenite. The
dewaxing may be accomplished with the catalyst in a fixed, fluid or
slurry bed. Typical dewaxing conditions include a temperature in
the range of from about 400-600.degree. F., a pressure of 500-900
psig, H.sub.2 treat rate of 1500-3500 SCF/B for flow-through
reactors and LHSV of 0.1-10, preferably 0.2-2.0. The dewaxing is
typically conducted to convert no more than 40 wt % and preferably
no more than 30 wt % of the hydroisomerate having an initial
boiling point in the range of 650-750.degree. F. to material
boiling below its initial boiling point.
[0053] GTL base stocks and base oils, hydroisomerized or isodewaxed
wax-derived base stocks and base oils, have a beneficial kinematic
viscosity advantage over conventional Group II and Group III base
stocks and base oils, and so may be very advantageously used with
the instant invention. Such GTL base stocks and base oils can have
significantly higher kinematic viscosities, up to about 20-50 cSt
at 100.degree. C., whereas by comparison commercial Group II base
oils can have kinematic viscosities, up to about 15 cSt at
100.degree. C., and commercial Group III base oils can have
kinematic viscosities, up to about 10 cSt at 100.degree. C. The
higher kinematic viscosity range of GTL base stocks and base oils,
compared to the more limited kinematic viscosity range of Group II
and Group III base stocks and base oils, in combination with the
instant invention can provide additional beneficial advantages in
formulating lubricant compositions.
[0054] In the present invention the hydroisomerate isodewaxate oil
can constitute all or part of the base stock oil.
[0055] One or more of these wax isomerate/isodewaxate base stocks
and base oils can be used as such or in combination with the
aforesaid GTL base stocks and base oils.
[0056] One or more of these waxy feed derived base stocks and base
oils, derived from GTL materials and/or other waxy feed materials
can similarly be used as such or further in combination with other
base stock and base oils of mineral oil origin, natural oils and/or
with other synthetic base oils.
[0057] The preferred base stocks or base oils derived form GTL
materials and/or from waxy feeds are characterized as having
predominantly paraffinic compositions and are further characterized
as having high saturates levels, low-to-nil sulfur, low-to-nil
nitrogen, low-to-nil aromatics, and are essentially water-white in
color.
[0058] Useful compositions of GTL base oils, hydroisomerized or
isodewaxed Fischer-Tropsch wax derived base oils, and wax-derived
hydroisomerized base oils are recited in U.S. Pat. Nos. 6,080,301;
6,090,989, and 6,165,949 for example, and are incorporated herein
in their entirety by reference.
[0059] Alkylene oxide polymers and interpolymers and their
derivatives containing modified terminal hydroxyl groups obtained
by, for example, esterification or etherification are useful
synthetic lubricating oils. By way of example, these oils may be
obtained by polymerization of ethylene oxide or propylene oxide,
the alkyl and aryl ethers of these polyoxyalkylene polymers
(methyl-polyisopropylene glycol ether having an average molecular
weight of about 1000, diphenyl ether of polyethylene glycol having
a molecular weight of about 500-1000, and the diethyl ether of
polypropylene glycol having a molecular weight of about 1000 to
1500, for example) or mono- and polycarboxylic esters thereof (the
acidic acid esters, mixed C.sub.3-8 fatty acid esters, or the
C.sub.13 Oxo acid diester of tetraethylene glycol, for
example).
[0060] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of mono-carboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl) sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl
sebacate, etc.
[0061] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols (preferably
the hindered polyols such as the neopentyl polyols e.g. neopentyl
glycol, trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol,
trimethylol propane, pentaerythritol and dipenta-erythritol) with
alkanoic acids containing at least about 4 carbon atoms (preferably
C.sub.5 to C.sub.30 acids such as saturated straight chain fatty
acids including caprylic acid, capric acid, lauric acid, myristic
acid, palmitic acid, stearic acid, arachic acid, and behenic acid,
or the corresponding branched chain fatty acids or unsaturated
fatty acids such as oleic acid).
[0062] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipenta-erythritol with one or more
monocarboxylic acids containing from about 5 to about 10 carbon
atoms.
[0063] Silicon-based oils are another class of useful synthetic
lubricating oils. These oils include polyalkyl-, polyaryl-,
polyalkoxy-, and polyaryloxy-siloxane oils and silicate oils.
Examples of suitable silicon-based oils include tetraethyl
silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl)silicate,
tetra-(4-methylhexyl) silicate, tetra-(p-tert-butylphenyl)
silicate, hexyl-(4-methyl-2-pentoxy) disiloxane, poly(methyl)
siloxanes, and poly-(methyl-2-mehtylphenyl) siloxanes.
[0064] Another class of synthetic lubricating oil is esters of
phosphorous-containing acids. These include, for example, tricresyl
phosphate, trioctyl phosphate, diethyl ester of decanephosphonic
acid.
[0065] Another class of oils includes polymeric tetrahydrofurans,
their derivatives, and the like.
[0066] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0067] In many cases it will be advantageous to employ only a GTL
base stock such as one derived from waxy Fischer-Tropsch
hydrocarbons for a particular wear resistant lubricant, while in
other cases one or more additional base stocks may be mixed with,
added to or blended with one or more of the GTL base stocks, e.g.,
Fischer-Tropsch derived base stocks. Such additional base stocks
may be selected from the group consisting of (i) natural base
stock, (ii) synthetic base stock, (iii) unconventional base stock
and mixtures thereof.
[0068] If a base stock blend is used it should contain at least 20
wt %, preferably at least 40 wt %, more preferably at least 60 wt
%, most preferably at least 80 wt % of the GTL base stock or base
oil, or slack wax or Fischer-Tropsch derived base stock, preferably
Fischer-Tropsch derived base stock. As is readily apparent, any
formulated oil utilizing such a blend while exhibiting performance
superior to that secured when such other base stock is used
exclusively will be inferior in performance to that achieved when
GTL base stocks, Fischer-Tropsch derived base stock or mixture
thereof is the only base stock employed.
[0069] In the lubricating composition of the present invention the
foregoing base stocks comprise a major amount of the lubricating
composition.
[0070] The lubricating composition of the present invention also
includes an antiwear and load carrying additive combination
comprising thiosalicylic acid and adenine. The weight ratio of
thiosalicylic acid to adenine used in the additive typically is in
the range of about 50:1 to 5:1, and preferably from 15:11 to 25:1.
Preferably the additive combination may also include a phosphate
ester or tricresyl phosphate load carrying additive. The weight
ratio of the combined thiosalicylic acid and adenine to phosphate
ester typically is in the range of about 1:1 to 1:50, and
preferably 1:10 to 1:30. The weight ratio of the combined
thiosalicylic acid and adenine to tricresyl phosphate typically is
in the range of about 1:1 to 1:50 and preferably 1:10 to 1:30.
[0071] The thiosalicylic acid and adenine combined additive is
present in the lubricant in an effective amount. Typically they
will comprise about 0.01 to about 1.0 wt %, and preferably from
about 0.05 wt % to about 0.5 wt %, based on the total weight of the
composition.
[0072] When a phosphate ester load carrying additive such as
tricresyl phosphate is employed the thiosalicylic acid, adenine and
phosphate ester additive will comprise about 0.01 wt % to about 5.0
wt % and preferably 0.5 wt % to 3.0 wt % of the lubricating
composition.
[0073] Other conventional additives which can be used in the
lubricants of the invention include oxidation inhibitors, antifoam
agents, viscosity index improvers, pour point depressants and the
like. These include hindered phenols, alkylated diphenyl amines,
benzotriazole derivatives, silicone oils and the like. In general
these other additive will be used in total amounts ranging from
about 0.5 wt % to about 15.0 wt %, based on the total weight of the
lubricating composition.
EXAMPLES AND COMPARATIVE EXAMPLES
[0074] Examples 1 to 5 and comparative examples 2 to 4 which follow
illustrate a few specific compositions in greater detail. These
consist of fully formulated lubricant AA, having a phosphate ester
base stock and TCP except where noted in Table 1. Also, in Table 1
"TSA" refers to thiosalicylic acid and DVP 560 is an aromatic
oligomer reaction product of Bisphenol A and phenol sold by Great
Lakes Chemicals, West Lafayette, IN, antiwear and load carrying
additive; lubricant BB, which had the same base stock and additives
of lubricant AA except it did not contain tricresyl phosphate.
[0075] The load carrying properties of these compositions were
evaluated in the extreme pressure Four-Ball wear test according to
the ASTM D 2783-88 procedure. In this test the last non-seizure
load (LNSL) was measured to establish difference between the
formulations. The formulations and results are given in Table 1.
TABLE-US-00002 TABLE 1 Formula- Amount of LNSL, tion Additive
Additive, wt% kg Comp. 1 AA TCP 3.0 40 Comp. 2 BB None 0.0 45
Example 1 BB TSA & Adenine 0.1 85 Example 2 BB TSA &
Adenine 1.0 90 (0.11%), TCP (0.9%) Example 3 BB TSA, Adenine
(0.1%), 2.0 100 TCP 1.9%) Example 4 BB TSA, Adenine (0.1%), 3.0 105
TCP (2.9%) Comp. 3 BB DVP 506 0.5 45 Comp. 4 BB DVP 506 3.0 50
Example 5 BB TSA & Adenine 0.5 110 (0.1%) and DVP 506
(0.4%)
[0076] The TSA adenine system was further evaluated in the
oxidation and corrosion test ASTM D 4636-86 at 425.degree. C. The
results are given in Table 2. TABLE-US-00003 TABLE 2 Formulation
Example 2 Example 3 Example 4 Comp. 1 KV @ 40.degree. C. (cSt)
Initial 26.78 26.78 25.72 25.85 Final 40.89 41.28 41.47 47.31 %
Increase 52.69 54.14 61.24 83.02 Total Acid No. (mgKOH) Initial
0.29 0.28 0.30 0.13 Final 2.73 3.73 3.89 8.98 % Increase 2.44 3.45
3.59 8.85 Deposits Vapor Light Medium Light Light Interface Light
Light Light Nil Liquid Nil Nil Nil Nil Silver Initial Wt,
g/cm.sup.2 1.9236 1.8440 1.7924 2.0184 Final Weight 1.9232 1.8435
1.7920 2.0180 Weight Change -0.00008 -0.0001 -0.00008 -0.00008
Aluminum Initial Weight 0.4997 0.4847 0.5092 0.5123 Final Weight
0.4996 0.4846 0.5091 0.5121 Weight Change -0.00002 -0.00002
-0.00002 -0.00004 Steel Initial Weight 1.4183 1.4135 1.4212 1.3968
Final Weight 1.4184 1.4134 1.4213 1.3968 Weight Change 0.00002
-0.00002 0.00002 0.0000 Titanium Initial Weight 1.4760 1.4455
1.4809 1.4324 Final Weight 1.4758 1.4453 1.4807 1.4323 Weight
Change -0.00004 -0.00004 -0.00004 -0.00002 Entire Tube Initial
Weight 929.60 896.60 918.10 926.45 Final Weight 917.60 886.00
906.95 913.90 Weight Change -12.00 -10.60 -11.15 -12.55 MIL-23699F
Ag Pass Pass Pass Pass Al Pass Pass Pass Pass Fe Pass Pass Pass
Pass Ti Pass Pass Pass Pass Sludge Pass Pass Pass Pass
[0077] Examples 6 to 8 and comparative examples 5 and 6 further
illustrate the advantages of the present invention. In these
instances formulation CC refers to a fully formulated lubricant
comprising a gas to liquid base oil and including the additive TCP
(comparative examples) or the TCP and additive combination of TSA
and adenine (the examples) in the amounts shown in Table 3. The
load carrying properties of these compositions were evaluated in
the extreme pressure Four-Ball Wear test according to the ASTM D
2783-88 procedure. In this test the last non-seizure load (LNSL)
was measured to establish the differences between the formulations.
The formulations and results are given in Table 3. TABLE-US-00004
TABLE 3 Formulation Additive Additive wt % LNSL, Kg Comp 5 CC TCP
0.5 60 Comp 6 CC TCP 3.0 60 Example 6 CC TCP 0.5 TSA 0.05 Adenine
-- 126 Example 7 CC TCP 0.5 TSA 0.1 Adenine -- 126 Example 8 CC TCP
0.5 TSA 0.5 Adenine -- 160
* * * * *
References