U.S. patent application number 11/637342 was filed with the patent office on 2007-06-21 for lubricant oil compositions containing gtl base stock(s) and/or base oil(s) and having improved resistance to the loss of viscosity and weight and a method for improving the resistance to loss of viscosity and weight of gtl base stock(s) and/or base oil(s) lubricant oil formulations.
Invention is credited to Charles Lambert Baker, James Thomas Carey, James William Gleeson, Margaret May-Som Wu.
Application Number | 20070142242 11/637342 |
Document ID | / |
Family ID | 38163550 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070142242 |
Kind Code |
A1 |
Gleeson; James William ; et
al. |
June 21, 2007 |
Lubricant oil compositions containing GTL base stock(s) and/or base
oil(s) and having improved resistance to the loss of viscosity and
weight and a method for improving the resistance to loss of
viscosity and weight of GTL base stock(s) and/or base oil(s)
lubricant oil formulations
Abstract
The present invention is directed to a method for improving the
performance of lubricating oils of high viscosity comprising GTL
base stock(s) and/or base oil(s) and lubricating oil comprising
such base stock(s) and/or base oil(s) in combination with an
effective amount of a polyolefin fluid having a kinematic viscosity
at 100.degree. C. in the range between about 10 to about 200
mm.sup.2/s.
Inventors: |
Gleeson; James William;
(Burke, VA) ; Wu; Margaret May-Som; (Skillman,
NJ) ; Carey; James Thomas; (Medford, NJ) ;
Baker; Charles Lambert; (Thornton, PA) |
Correspondence
Address: |
ExxonMobil Research and Engineering Company
P. O. Box 900
Annandale
NJ
08801-0900
US
|
Family ID: |
38163550 |
Appl. No.: |
11/637342 |
Filed: |
December 12, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60750562 |
Dec 15, 2005 |
|
|
|
Current U.S.
Class: |
508/221 |
Current CPC
Class: |
C10M 2205/028 20130101;
C10M 111/04 20130101; C10M 2205/024 20130101; C10M 169/04 20130101;
C10N 2020/019 20200501; C10M 2205/0245 20130101; C10M 2205/0265
20130101; C10M 2205/173 20130101; C10N 2020/04 20130101; C10N
2040/04 20130101; C10N 2020/071 20200501; C10N 2020/085 20200501;
C10N 2020/02 20130101; C10N 2030/10 20130101; C10M 2205/0225
20130101; C10N 2040/08 20130101; C10N 2040/25 20130101; C10N
2030/08 20130101; C10N 2040/252 20200501; C10M 2205/026 20130101;
C10N 2030/02 20130101; C10M 2203/1025 20130101; C10M 2205/022
20130101; C10M 2205/0285 20130101 |
Class at
Publication: |
508/221 |
International
Class: |
C10M 149/10 20060101
C10M149/10 |
Claims
1. A method for reducing the loss of viscosity and weight and
improving the oxidation stability and low temperature properties of
lubricating oil formulation by employing a base stock comprising a
GTL base stock and/or base oil in combination with a polyolefin
fluid, said polyolefin fluid being characterized by a viscosity in
the range of about 2 to 1000 mm.sup.2/s at 100.degree. C., a number
average molecular weight in the range of about 200 to 10,000.
2. The method of claim 1 wherein the lubricating oil formulation
has a viscosity in the range of about 2 to 1000 mm.sup.2/s at
100.degree. C.
3. The method of claim 1 wherein the polyolefin fluid is combined
with the GTL in an amount in the range of about 0.1 to 90 wt %
based on the weight of the combination.
4. The method of claim 1 wherein the polyolefin fluid is a
copolymer of a first alpha olefin selected from ethylene,
propylene, 1-butylene and a second alpha olefin different from the
first selected from the group of C.sub.2-C.sub.30 straight or
branched chain alphaolefins and mixtures thereof wherein when one
of the alpha olefin used is ethylene the ethylene content of the
poly olefin fluid is not more than 50 wt %.
5. The method of claim 1 wherein the polyolefin fluid is a poly
alpha olefin homo or copolymer made from alpha olefins selected
from the group of C.sub.8 to C.sub.18 alpha olefins and mixtures
thereof.
6. The method of claim 1, 2, 3, 4 or 5 wherein the polyolefin fluid
has a molecular weight distribution (MWD) of from 1.00 to 4.
7. The method of claim 1, 2, 3, 4 or 5 wherein the GTL base stock
and/or base oil is a hydrodewaxed or hydroisomerized
Fischer-Tropsch material.
8. The method of claim 7 wherein the Fischer-Tropsch material is
Fischer-Tropsch wax.
9. The method of claim 1, 2, 3, 4 or 5 wherein the lubricating oil
formulation has a kinematic viscosity in the range of about 2 to
500 mm.sup.2/s at 100.degree. C.
10. The method of claim 9 wherein the GTL base oil has a kinematic
viscosity in the range of about 1.5 to 50 mm.sup.2/s at 100.degree.
C.
11. The method of claim 1, 2, 3, 4 or 5 wherein the polyolefin
fluid has a kinematic viscosity in the range about 4 to 800
mm.sup.2/s at 100.degree. C.
12. The method of claim 1, 2, 3, 4 or 5 wherein the polyolefin
fluid has a kinematic viscosity in the range of about 10 to 500
mm.sup.2/s at 100.degree. C.
13. The method of claim 1, 2, 3, 4 or 5 wherein the polyolefin
fluid has a kinematic viscosity in the range of about 10 to 200
mm.sup.2/s at 100.degree. C.
14. The method of claim 1 wherein the base stock further contains a
hydrodewaxate or hydroisomerate of waxy feed derived from mineral
oil.
15. The method of claim 1 or 14 wherein the base stock further
contains a mineral oil base stock, a Group V synthetic base stock
or mixture thereof.
16. The method of claim 15 wherein the GTL base stock and/or base
oil constitutes 5 to 100 wt % of the total of the base oil.
17. The method of claim 16 wherein the GTL base stock and/or base
oil constitutes 40 to 100 wt % of the total of the base oil.
18. The method of claim 16 wherein the GTL base stock and/or base
oil constitute 70 to 100 wt % of the total of the base oil.
19. The method of claim 16 wherein the GTL base stock and/or base
oil constitutes 90 to 100 wt % of the total of the base oil.
20. A base stock exhibiting an enhanced resistance to reduction in
the loss of weight and viscosity and improved oxidation stability
and low temperature properties comprising a mixture of GTL base
stock and/or base oil in combination with a polyolefin fluid, said
polyolefin fluid being characterized by a viscosity in the range of
about 2 to 1000 mm.sup.2/s at 100.degree. C. and a number average
molecular weight in the range of about 200 to 10,000 and a
molecular weight distribution of 1.00 to 4.
21. The base stock of claim 20 wherein the polyolefin fluid is
present in an amount in the range of about 0.1 to 90 wt % based on
the total weight of the base stock.
22. The base stock of claim 20 wherein the polyolefin fluid is a
copolymer of a first alpha olefin selected from ethylene,
propylene, 1-butylene and a second alpha olefin different from the
first selected from the group of C.sub.2-C.sub.30 straight or
branched chain alpha-olefin and mixtures thereof wherein when one
of the alpha olefins used is ethylene, the ethylene content of the
polyolefin fluid is not more than 50 wt %.
23. The base stock of claim 20 wherein the polyolefin fluid is a
polyalpha olefin homo- or copolymer made from C.sub.8 to C.sub.18
alpha olefin.
24. The base stock of claim 20, 21, 22 or 23 wherein the GTL base
stock and/or base oil is a hydrodewaxed or hydroisomerized
Fischer-Tropsch liquid hydrocarbon composition comprising
paraffinic hydrocarbon components in which the extent of branching,
as measured by the percentage of methyl hydrogens (BI), and the
proximity of branching, as measured by the percentage of recurring
methylene carbons which are four or more carbons removed from an
end group or branch (CH2.gtoreq.4), are such that: (a) BI-0.5
(CH.sub.2.gtoreq.4)>15; and (b) BI+0.85
(CH.sub.2.gtoreq.4)<45 as measured over said liquid hydrocarbon
composition as a whole and further characterized as a mixture of
branched paraffinic characterized in that the GTL base oil contains
at least 90% of a mixture of branched paraffins wherein said
branched paraffins are paraffinic having a carbon chain length of
about C.sub.20 to about C.sub.40, a molecular weight of about 280
to about 562, a boiling range of about 650.degree. F. to about
1050.degree. F., and wherein said branched paraffins contain up to
four alkyl branches and wherein the free carbon index of said
branched paraffins is at least about 3.
25. The base stock of claim 24 wherein the GTL base stock and/or
base oil has a kinematic viscosity in the range of about 1.5 to 50
mm.sup.2/s @ 100.degree. C.
26. The base stock of claim 25 wherein the polyolefin fluid has a
kinematic viscosity in the range of about 4 to 800 mm.sup.2/s @
100.degree. C.
27. The base stock of claim 25 wherein the polyolefin fluid has a
kinematic viscosity in the range of about 10 to 500 mm.sup.2/s @
100.degree. C.
28. The base stock of claim 25 wherein the polyolefin fluid has a
kinematic viscosity in the range of about 10 to 200 mm.sup.2/s
@100.degree. C.
Description
[0001] This application claims the benefit of U.S. Ser. No.
60/750,562 filed Dec. 15, 2005.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to high kinematic viscosity
lubricating oils and lubricating oil formulations comprising wax
hydroisomerate/hydrodewaxate base stock(s) and/or base oil(s) and
the improvement of the oxidative stability/resistance to weight
loss of such lubricating oils/lubricating oil formulations.
[0004] 2. Description of the Related Art
[0005] Base stocks/base oils that simultaneously have high quality
and low cost are not readily available, thus limiting the quality
and/or increasing the cost of high viscosity lubricants. Thermal
stability, that is, the resistance to decomposition upon exposure
to high temperatures but with minimal exposure to air, is an
importance property of lubricating oils needed in industrial
applications such as oils that circulate through industrial
equipment, oils that lubricant gear boxes, oils that lubricant
neutral gas engines, hydraulic oils, etc. Thermal decomposition of
lubricants contribute to deposit formation. For example, in large
marine engines, deposits formed in the hot regions of the engine
can interfere with heat transfer in the piston cooling spaces.
Additives are not readily available that improve thermal stability,
but good oxidative stability and good low temperature properties
and resistance to weight loss are still necessary/important
properties of such lubricants.
[0006] Heretofore only relatively low quality conventional Group I
mineral oil base stocks and high quality/high cost
poly-alpha-olefin (PAO) base stocks have been available at high
viscosities (kinematic viscosities greater than about 120
mm.sup.2/s at 40.degree. C.) in sufficient quantities to formulate
such lubricants. Some hydroprocessed base stocks/base oils can be
used to formulate high kinematic viscosity lubricants and
lubricating oil formulations with better oxidative stability than
most conventional mineral oil base stocks at cost somewhat below
those of PAO base oils/base stocks, but are not available above
about 120 mm.sup.2/s at 40.degree. C. (.about.600 SUS).
Manufacturing base stocks/base oils with higher viscosities by
hydroprocessing technology, however, is characterized by low yield
and haze formation that interferes with lubricant filtration and
contaminant detection.
[0007] To produce high viscosity lubricants use has been made of
thickener materials. Such thickener materials are characterized as
relatively high molecular weight high viscosity polymeric materials
such as polyisobutenes, styrene-isoprene copolymers, olefin
copolymers, poly-alpha-olefins, polymethacrylates, polyacrylates,
copolymers of vinyl acetate and ethylene, dialkylfumarate and vinyl
acetate. The use of such thickener, however, while resulting in a
formulation displaying high initial viscosity, produces formulation
marked by significant loss in kinematic viscosity and in weight
over time, i.e., during use.
[0008] WO 03/076555 is directed to lubricant blend composition
comprising two major components, a copolymer made from ethylene
with one or more alpha olefins, the copolymer containing not more
than 50 wt % ethylene and having a number average molecular weight
from 400 to 10,000 and a polyalphaolefin fluid or a hydroprocessed
oil having a VI greater than 80. The hydroprocessed oil is further
described as being a Group II oil, a Group III oil, or a F-T wax
isomerate. In the Examples the ethylene-alpha-olefin copolymers
were combined only with Group III stocks having a KV @ 100.degree.
C. of 3.98 or with Group II stocks.
[0009] JP 2503536B2 is directed to base oils comprising 50-99.8 wt
% of a base oil having kinematic viscosity @ 100.degree. C. in the
range 1-20 mm.sup.2/s, said base oil being selected from synthetic
hydrocarbons and esters, and an ethylene olefin copolymer having
kinematic viscosity @ 100.degree. C. in the range 1,000 to 10,000
mm.sup.2/s. The object of adding the ethylene copolymer to the base
oil is to achieve viscosity increase, superior shear stability,
heat and oxidation resistance. The base oil, while identified as
including synthetic hydrocarbons defines such synthetic
hydrocarbons as being alpha olefin oligomers (i.e., PAO),
alkylbenzenes, alkyl naphthalene, "etc.", having a kinematic
viscosity @ 100.degree. C. of 1 to 20 mm.sup.2/s. In the Examples,
only PAO was used as base oil.
[0010] U.S. Pat. No. 6,103,099 is directed to the production of
synthetic lubricants and lubricant base stocks without dewaxing.
The base stock is produced by hydroisomerizing a waxy hydrocarbon
feed fraction having an initial boiling point in the
650-750.degree. F. range and an end point of at least 1050.degree.
F., synthesized by a slurry F-T hydrocarbon synthesis process, the
hydroisomerization forming a hydroisomerate containing the desired
base stock which is recovered without dewaxing the hydroisomerate.
This base stock can be combined with conventional additives,
including VI improvers or viscosity modifiers. VI improvers include
acrylic polymers and copolymers, e.g., methacrylates and,
polymethacrylates as well as olefin copolymers.
[0011] U.S. Pat. No. 6,332,974 is directed to wide-cut lubricant
base stocks made by hydroisomerizing and then catalytically
dewaxing a waxy F-T synthesized hydrocarbon reaction feed. This
base stock can be additized with VI improver and viscosity
modifiers including acrylic polymers and copolymers such as
polymethacrylates, and polyalkylmethacrylates as well as olefin
copolymers. See also U.S. Pat. No. 6,090,989.
[0012] WO 01/57166 is directed to formulated lubricant oils
containing high performance base oils derived from highly
paraffinic hydrocarbons comprising wax isomerate paraffinic
hydrocarbon base stock components in combination with additives.
Additives include viscosity modifier polymers having molecular
weights typically in the range of about 10,000 to 1,000,000, and
include hydrogenated styrene-isoprene block copolymers, rubbers
based on ethylene and propylene (i.e., olefin copolymers), high
molecular weight acrylate or methacrylates, polyisobutylenes, and
other materials soluble in the base stock which, when added to the
base stocks confer the required viscosity to achieve the desired
high temperature viscosity grade.
[0013] EP application 0 088 453 is directed to a lubricating
composition containing PAO, ethylene-alphaolefin copolymer or
hydrogenated polyisoprene having a kinematic viscosity @
100.degree. C. of 40 to -1000 mm.sup.2/s, a low viscosity synthetic
hydrocarbon and/or a low viscosity ester, and optionally an
additive package. The low viscosity synthetic hydrocarbons are
identified as having viscosities of from 1 to 10 mm.sup.2/s
consisting primarily of oligomers of alphaolefins and alkylated
benzenes. In the example using ethylene-alpha olefin copolymers of
different viscosities the base oil to which the copolymer is added
is PAO. While the ethylene-alpha-olefin copolymer of EP 0 088 453
is shown to be more stable to viscosity and viscosity index losses
from oxidation than was a commercial thickener, even the
PAO-ethylene alpha olefin blends exhibited some significant
deterioration in viscosity and VI after aging.
[0014] U.S. Pat. No. 3,923,919 is directed to ethylene propylene
copolymers as oils, the copolymers containing 29-71 mol percent
ethylene. The copolymer of this patent is itself seen as being the
oil having a viscosity at 210.degree. F. of 1-60 mm.sup.2/s
maximum. When additized with an oxidation inhibitor (mixture of
amines, catechol and a metallic dithiocarbamate) the
ethylene-propylene copolymer of U.S. Pat. No. 3,923,919 exhibited
oxidative stability superior to that exhibited by a Super Refined
Mineral oil additized with the same antioxidant. Similarly an
ethylenepropylene copolymer exhibited thermal and shear stability
superior to that of Super Refined Mineral oil (no report of
additives being present).
[0015] U.S. Pat. No. 5,498,809 is directed to oil soluble
copolymers, derived from ethylene and 1-butene, which have a number
average molecular weight between 1,500 and 7,500, at least about
30% of all polymer chains terminated with ethylvinyledene group,
and ethylene-derived content of not greater than about 50 wt %.
Lubricating oil additive can be prepared by functionalizing and
dewaxing these copolymers.
DESCRIPTION OF THE INVENTION
[0016] It has been discovered that lubricating oils of high
viscosity in the range of about 2.0 to 1000 mm.sup.2/s, preferably
2 to 500 mm.sup.2/s, more preferably 2 to 350 mm.sup.2/s, still
more preferably about 4 to 200 mm.sup.2/s @ 100.degree. C. prepared
from GTL base stock(s) and/or base oil(s) having a viscosity in the
range of 1.5 mm.sup.2/s to 50 mm.sup.2/s, preferably 2 to 35
mm.sup.2/s, more preferably 2 to 20 mm.sup.2/s @ 100.degree. C.
additized with a polyolefin fluid having a viscosity at 100.degree.
C. in the range of about 2 to 1,000 mm.sup.2/s exhibit improved
oxidation stability, low temperature properties, viscosity
retention and shear stability/weight retention superior to that
exhibited by Gas-To-Liquids (GTL) base stock(s) and/or base oil(s)
additized with conventional viscosity modifiers and superior the to
that exhibited by Group I and Group II oils additized with the same
polyolefin fluid or with a known viscosity modifier.
[0017] The polyolefin fluid used as viscosity modifier in the
present invention is characterized as having a kinematic viscosity
in the range of about 2 to 1,000 mm.sup.2/s, preferably about 4 to
800 mm.sup.2/s, more preferably about 10 to 500 mm.sup.2/s, most
preferably about 10 to 200 mm.sup.2/s at 100.degree. C., and a
molecular weight (number average) in the range of about 200 to
10,000, preferably about 400 to 4,000, more preferably about 600 to
3,000. The molecular weight distribution (MWD) of the polyolefin
fluid ranges from 1.00 to 4, preferably 1.01 to 3, preferably 1.01
to 2.5. Usually narrower MWD is preferred. When the polyolefin
fluid is a copolymer of ethylene with a second alpha olefin the
polyolefin fluid is also characterized as containing not more than
50 wt % ethylene.
[0018] The polyolefin fluid can be derived from the
copolymerization of a first alpha-olefin with one or more second
alpha-olefins. The first alpha-olefin, typically ethylene,
propylene, 1-butylene is polymerized with one or more second
olefin(s) different from the first, said second olefin different
from the first being selected from the group of C.sub.2-C.sub.30
straight or branched chain alpha olefins, and mixtures of such
olefins, preferably C.sub.2-C.sub.14 straight or branched chain
alpha-olefins and mixtures of said olefins. When the alpha olefin
is branched, it is preferred that the branch be at least two
carbons away from the double bond.
[0019] The polyolefin fluid can also be a poly-alpha olefin wherein
the polymer is a homopolymer made from one or more olefins selected
from C.sub.8-C.sub.18 alpha olefin monomers or a copolymer of a
mixture of such monomers. In the case of the homopolymers, they may
be predominantly dimers, trimers and tetramers with minor amounts
of higher oligomers.
[0020] Preferably the polyolefin fluid is a copolymer of ethylene
and an alpha olefin, the alpha olefin being represented by the
formula H.sub.2C.dbd.CHR.sub.1 wherein R.sub.1 is a straight or
branched chain alkyl radical selected from the group of alkyl
radicals having 1 to 22 carbons, or mixtures thereof, preferably 1
to 12 carbons or mixtures thereof, more preferably propylene or
butylene, most preferably propylene or butylenes or the mixture of
the two.
[0021] The most suitable source of ethylene can be pure ethylene
stream specially made for polymerization purpose (polymer grade
ethylene). It can also be a dilute ethylene stream, from various
source, such as refinery dilute ethylene stream, stream craker, or
other source of ethylene. The alpha-olefins, such as propylene,
1-butene, can be available from petrochemical plant, light gas from
catalytic fluid cracking process in refinery, from steam cracking
of propane, butane, light naphtha, naphtha, etc. Most desirable
source are those dilute propylene or butene stream, such PP stream
containing propane/propylene or stream containing 1,2,i-butenes in
butanes (BB stream) (C.sub.4 stream, Raffinate 1 or Raffinate 2
stream from refinery). Other Linear Alpha Olefin (LAO) source from
ethylene growth process, which produces 1-butene, 1-hexene,
1-octene, 1-decene, 1-dodecene, 1-tetradeceen, 1-hexadecene, etc.
are also most suitable. Other C.sub.2 to C.sub.18 LAO sources, such
as from steam thermal cracking of wax, either petroleum derived wax
or wax produced in a Fischer-Tropsch Hydrocarbon Synthesis process,
are also suitable. The LAOs derived from steam thermal cracking of
FT wax is most suitable because they are usually low in undesirable
S, N, cyclic or aromatic components which is usually a deactivator
for the polymerization reaction. LAO produced from metathesis of
internal olefins with ethylene or LAO in the presence of other
olefins or saturated hydrocarbons are also suitable for the
reaction.
[0022] The polyolefin fluid can be made by reacting the olefin
monomers in the presence of a conventional Ziegler, Ziegler-Natta
catalyst, e.g., TiCl.sub.4, TiCl.sub.3, VCl.sub.4 or VOCl.sub.3
with promoter, such as magnesium chloride, zinc chloride, etc and
with activator(s), including trialkylaluminum, trialkylboron,
and/or a halide such as organo-aluminum halides and/or hydrogen
halides. There are many variations of Ziegler or Ziegler-Natta
catalysts, as described in the book Ziegler-Natta Catalysts and
Polymerizations by John Boor, Jr., Academic Press, NY, 1979.
[0023] While the olefin copolymers (OCP) made using Ziegler-Natta
catalysts tend to have number average molecular weight of about
10,000 or more, and many of the conventional VI Improver OCP are
made by such method, as reviewed in Chapter 10 of Lubricant
Additives, Chemistry and Applications. Ed. By L. R. Rudnick, Marcel
Dekker, Inc., New York 2003, the process using Zieglis or
Ziegler-Natta catalysts can be used to prepare the polyolefin fluid
suitable for use in the present invention provided case is taken to
produce a polyolefin fluid meeting the viscosity, molecular weight,
MWD limits previously recited, and where appropriate the ethylene
content limit.
[0024] Preferably the polyolefin fluids used in the present
invention are produced using a catalyst system comprising a
metallocene and an aluminoxane. See, for example, U.S. Pat. No.
4,668,834; U.S. Pat. No. 4,704,491; WO 90/1503; U.S. Pat. No.
5,043,515; U.S. Pat. No. 5,859,159; U.S. Pat. No. 5,498,809. The
polyolefin fluids which are preferred in the present invention are
those synthesized using metallocene catalysts and are characterized
as having a molecular weight distribution (MWD) defined as the
ratio of the weight average molecular weight to the number average
molecular weight of about 4 or less, preferably about 3 or less,
more preferably about 2.5 or less. The polyolefin fluids have a MWD
of from about 1 to 3.5, preferably from about 1 to 3. Both number
average and weight average molecular weight can be determined by
the technique of gel permeating chromatograph (GPC) with a suitable
calibration curve, as in know to those skilled in the art.
[0025] The polymerization reaction for the production of polyolefin
fluids from a first alpha olefin such as ethylene, propylene,
1-butylene reacted with a second, different alpha olefin which is a
straight or branched chain alpha olefin selected from
C.sub.2-C.sub.30 alpha olefin and mixtures thereof, preferably
C.sub.1-C.sub.14 straight or branched chain alpha olefin and
mixtures thereof is conducted in the presence of a catalyst system
comprising at least one metallocene (e.g., a
cyclopentadienyl-transition metal compound) and preferably an
activator, e.g., an alumoxane compound. The term metallocene refers
to compounds containing a coordination bond between a transition
metal and at least one cyclopentadiene ring structure. The term
cyclopentadiene ring structure includes saturated or unsaturated
polycyclic structures such as indenyl and fluorenyl which
incorporate a five-membered ring. The co-monomer content can be
controlled through the selection of the metallocene catalyst
component and by controlling the relative proportions of the feed
olefins, usually ethylene and an alpha-olefin, e.g., ethylene and
1-butene or ethylene and propylene, or ethylene and 1-pentene, or
ethylene and propylene and 1-butene.
[0026] The catalysts employed in the production of these polyolefin
fluids, are organometallic coordination compounds which are
cyclopentadienyl derivatives of a Group 4b metal of the Periodic
Table of the Elements (56th Edition of Handbook of Chemistry and
Physics, CRC Press, 1975) and include mono-, di- and
tricyclopentadienyls and their derivatives of the transition
metals. Particularly desirable are the metallocenes of a Group 4b
metal such as titanium, zirconium, and hafnium. These metallocenes
are further activated with an alumoxane. The alumoxanes employed in
forming the reaction product with the metallocenes are themselves
the reaction products of an aluminum trialkyl with water or
precursors which act as water source, such as copper sulfate
hydrates.
[0027] In general, at least one metallocene compound is employed in
the formation of the catalyst. Metallocene is a metal derivative of
a cyclopentadiene. The metallocenes usefully employed in accordance
with this invention contain at least one cyclopentadiene ring. The
metal is selected from the Group 4b preferably titanium, zirconium,
and hafnium, and most preferably hafnium and zirconium. The
cyclopentadienyl ring can be unsubstituted or contain one or more
substituents (e.g., from 1 to 5 substituents) such as, for example,
a hydrocarbyl substituent (e.g., up to 5 C.sub.1 to C.sub.5
hydrocarbyl substituents) or other substituents, e.g., such as, for
example, a trialkyl silyl substituent. The metallocene can contain
one, two, or three cyclopentadienyl rings; however, two rings are
preferred.
[0028] Useful metallocenes can be represented by the general
formulas: (C.sub.p).sub.mMR.sub.nX.sub.q (I) wherein Cp is a
cyclopentadienyl ring, M is a Group 4b transition metal, R is a
hydrocarbyl group or hydrocarboxy group having from 1 to 20 carbon
atoms, X is a halogen, and m is a whole number from 1 to 3, n is a
whole number from 0 to 3, and q is a whole number from 0 to 3.
(C.sub.5R'.sub.k).sub.gR''.sub.s(C.sub.5R'.sub.k)MQ.sub.3-g (II)
and R''.sub.s(C.sub.5R'.sub.k).sub.2MQ' (III) wherein
(C.sub.5R'.sub.k) is a cyclopentadienyl or substituted
cyclopentadienyl, each R' is the same or different and is hydrogen
or a hydrocarbyl radical such as alkyl, alkenyl, aryl, alkylaryl,
or arylalkyl radical containing from 1 to 20 carbon atoms, a
silicon containing hydrocarbyl radical, or hydrocarbyl radicals
wherein two carbon atoms are joined together to form a
C.sub.4-C.sub.6 ring, R'' is a C.sub.1-C.sub.4 alkylene radical, a
dialkyl germanium or silicon, or an alkyl phosphine or amine
radical bridging two (C.sub.5R'.sub.k) rings, Q is a hydrocarbyl
radical such as aryl, alkyl, alkenyl, alkylaryl, or aryl alkyl
radical having from 1-20 carbon atoms, hydrocarboxy radical having
from 1-20 carbon atoms or halogen and can be the same or different
from each other, Q' is an alkylidene radical having from 1 to about
20 carbon atoms, s is 0 or 1, g is 0, 1 or 2, s is 0 when g is 0, k
is 4 when s is 1, and k is 5 when s is 0, and M is as defined
above. Exemplary hydrocarbyl radicals are methyl, ethyl, propyl,
butyl, amyl, isoamyl, hexyl, isobutyl, heptyl, octyl, nonyl, decyl,
cetyl, 2-ethylhexyl, phenyl and the like. Exemplary silicon
containing hydrocarbyl radicals are trimethylsilyl, triethylsilyl
and triphenylsilyl. Exemplary halogen atoms include chlorine,
bromine, fluorine and iodine and of these halogen atoms, chlorine
is preferred. Exemplary hydrocarboxy radicals are methoxy ethoxy,
butoxy, amyloxy and the like. Exemplary of the alkylidene radicals
is methylidene, ethylidene and propylidene.
[0029] The alumoxane compounds useful in the polymerization process
may be cyclic or linear or the combination of the two. Cyclic
alumoxanes may be represented by the general formula
(R--Al--O).sub.n while linear alumoxanes may be represented by the
general formula R(R--Al--O).sub.n'AlR.sub.2. In the general formula
R is a C.sub.1-C.sub.5 alkyl group such as, for example, methyl,
ethyl, propyl, butyl and pentyl, n is an integer of from 3 to 20,
and n' is an integer from 1 to about 20. Preferably, R is methyl
and n and n' are 4-18. Generally, in the preparation of alumoxanes
from, for example, aluminum trimethyl and water, a mixture of the
linear and cyclic compounds is obtained.
[0030] The alumoxane can be prepared in various ways. Preferably,
they are prepared by contacting water with a solution of aluminum
trialkyl, such as, for example, aluminum trimethyl, in a suitable
organic solvent such as toluene or an aliphatic hydrocarbon. For
example, the aluminum alkyl is treated with water in the form of a
moist solvent. In an alternative method, the aluminum alkyl such as
aluminum trimethyl can be desirably contacted with a hydrated salt
such as hydrated copper sulfate or ferrous sulfate. Preferably, the
alumoxane is prepared in the presence of a hydrated ferrous
sulfate. The method comprises treating a dilute solution of
aluminum trimethyl in, for example, toluene, with ferrous sulfate
represented by the general formula FeSO.sub.4.7H.sub.2O. The ratio
of ferrous sulfate to aluminum trimethyl is desirably about 1 mole
of ferrous sulfate for 6 to 7 moles of aluminum trimethyl. The
reaction is evidenced by the evolution of methane. General method
to produce methylaluminoxane (MAO) or other alumoxane can be found
in many patents, U.S. Pat. No. 5,663,394, U.S. Pat. No. 5,693,838,
U.S. Pat. No. 6,194,340, U.S. Pat. No. 6,518,445, etc.
[0031] The mole ratio of aluminum in the alumoxane to total metal
in the metallocenes which can be usefully employed can be in the
range of about 0.5:1 to 5000:1, and desirably about 1:1 to 1000:1.
Preferably, the mole ratio will be in the range of about 500:1 to
5:1 and most preferably about 250:1 to 5:1.
[0032] The solvents used in the preparation of the catalyst system
are inert hydrocarbons, in particular a hydrocarbon that is inert
with respect to the catalyst system. Such solvents are well known
and include, for example, isobutane, butane, pentane, hexane,
heptane, octane, cyclohexane, methylcyclohexane, toluene, xylene
and the like.
[0033] Polymerization is generally conducted at temperatures
ranging between about 20.degree. C. and 300.degree. C., preferably
between about 30.degree. C. and 200.degree. C. The polymerization
feeds, including the olefins, the solvents and any other feed
gases, preferably are purified by passing through molecular sieves
and/or oxygenate removal catalyst beds, as typically practiced in
polyolefins synthesis. The purpose of the purification is to remove
water, oxygenates or any other trace polar components that can
deactivate the polymerization catalysts. Usually highly purified
feed streams result in high catalyst productivities and high lube
selectivity, simplified work up or product isolation step, narrower
molecular weight distribution. All these are beneficial for an
economical process and more desirable product. Reaction time is not
critical and may vary from several hours or more to several minutes
or less, depending upon factors such as reaction temperature and
the like. One of ordinary skill in the art may readily obtain the
optimum reaction time for a given set of reaction parameters by
routine experimentation.
[0034] The catalyst systems described herein are suitable for the
polymerization of ethylene and alpha-olefins in solution over a
wide range of pressures. The polymerization can be completed at a
pressure of from about 10 to 3,000 bar. The polymerization reaction
can be conducted in batch mode, semi-batch or semi-continuous mode,
or in continuous stir tank reactor (CSTR) mode.
[0035] After polymerization and, optionally, deactivation of the
catalyst (e.g., by conventional techniques such as contacting the
polymerization reaction medium with water or an alcohol, such as
methanol, propanol, isopropanol, etc., or cooling or flashing the
medium to terminate the polymerization reaction), the product
polymer can be recovered by distillation under vacuum to remove
light fraction, which has a boiling point below 650.degree. F. at
atmospheric pressure. The residual oil fraction can be used as is
for this invention. Or more preferably, the residual oil fraction
is further hydrogenated using standard hydrofinishing conditions,
such as under 500-2000 psi H.sub.2 pressure, 100-250.degree. C. and
2 wt % Nickel on Kieselguhr catalyst for proper amount of time to
reduce the degree of unsaturation down to low bromine number,
usually below 2. Usually, the lower the bromine number the better
the product, especially the better oxidative stability.
[0036] The polymerization may be conducted employing the liquid
alpha-olefin reactant as solvent. For example, 1-butene or
propylene or other appropriate alpha-olefin liquid, can be used as
the reaction medium. Alternatively, polymerization may be
accomplished in the presence of a hydrocarbon inert to the
polymerization such as butane, isobutane, pentane, isopentane,
hexane, isooctane, decane, toluene, xylene, and the like.
[0037] Another method to produce these polyolefin fluids is by
using Friedel-Crafts polymerization catalysts. For example, the
high viscosity polyolefin fluids can be made from ethylene and
alpha-olefins in range from 0% ethylene to 50 wt % ethylene as
feed. The other alpha-olefins can be propylene, 1-butene, mixed
butenes or mixed butanes in BB stream, linear alpha-olefins,
including 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene,
1-hexadecene, 1-octadecene, or the mixture of them. The amount of
these alpha-olefins in the feed ranges from 50 wt % to 100 wt
%.
[0038] The PAO's, which are known materials and fall within the
present definition of polyolefin fluids as used herein are
generally available on a major commercial scale from suppliers such
as ExxonMobil Chemical Company, Chevron, BP, and others, typically
vary in number average molecular weight from about 250 to about
3000, or higher, and PAO's may be made in kinematic viscosities up
to about 100 mm.sup.2/s (100.degree. C.), or higher, but those
having a number average molecular weight in the range 200 to
10,000, preferably 400 to 4,000, more preferably 600 to 3,000 and
kinematic viscosity in the range 2 to 1,000, preferably 4 to 800
mm.sup.2/s, more preferably 4 to 500 mm.sup.2/s, most preferably 4
to 20 mm.sup.2/s at 100.degree. C. are the ones suitable for use
herein. The PAO's are typically comprised of hydrogenated polymers
or oligomers of alphaolefins with the individual alpha olefin
monomers of about C.sub.8 to about C.sub.18 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. Depending on the viscosity
grade and the starting oligomer, the PAO's may be predominantly
trimers and tetramers of the starting olefins, with minor amounts
of the higher oligomers also being present.
[0039] 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; 4,827,064; 4,827,073;
4,910,355; 4,956,122; and 5,068,487. The dimers of the C.sub.14 to
C.sub.18 olefins are described in U.S. Pat. No. 4,218,330.
[0040] Methods to produce these PAOs can be found in U.S. Pat. Nos.
3,742,082, 5,068,487, etc. Some of these PAOs are available
commercially. For example SpectraSyn.TM. 40 and SpectraSyn.TM. 100
are available from ExxonMobil Chemical Co. They are suitable as
part of the components for this invention.
[0041] The polyolefin fluid is combined with GTL base stock(s)
and/or base oil(s) in an amount of from about 0.1 to 90 wt %,
preferably about 20 to 80 wt %, more preferably about 40 to 60 wt %
based on the total weight of the combination. The amount of
polyolefin fluid used in the blends depends on the viscosities of
the polyolefin fluid and the desirable finished lubricant
viscosities.
[0042] Gas-To-Liquids (GTL) base stock and/or base oil include base
stocks and/or base oils derived from one or more GTL materials.
[0043] 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, gaseous hydrogen-containing compounds, and/or elements
as feedstocks such as hydrogen, carbon dioxide, carbon monoxide,
water, methane, ethane, ethylene, acetylene, propane, propylene,
propane butane, butylenes, and butynes. GTL base stocks and/or 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/or base oils include
oils boiling in the lube oil boiling range separated from GTL
materials such as for example, by distillation, or thermal
diffusion, etc., and subsequently subjected to well known solvent
or catalytic dewaxing processes to produce lube oils of low pour
point; synthesized wax isomerates, comprising, for example,
hydrodewaxed or hydroisomerized/catalytic (or solvent) dewaxed
synthesized waxy hydrocarbons; hydrodewaxed or
hydroisomerized/catalytic (or solvent) dewaxed Fischer-Tropsch
(F-T) material (i.e., hydrocarbons, waxy hydrocarbons, waxes and
possible analogous oxygenates); preferably hydrodewaxed or
hydroisomerized/catalytic (or solvent) dewaxed F-T waxy
hydrocarbons, or hydrodewaxed or hydroisomerized/catalytic (or
solvent) F-T waxes, hydrodewaxed or hydroisomerized/catalytic (or
solvent) dewaxed synthesized waxes, or mixtures thereof. The GTL
base stocks and/or base oil may be used as such or in combination
with other hydrodewaxed or hydroisomerized/catalytic (or solvent)
dewaxed waxy materials comprising, for example, hydrodewaxed or
hydroisomerized/catalytic (or solvent) dewaxed
mineral/petroleum-derived waxy hydrocarbons, hydrodewaxed or
hydroisomerized/catalytic (or solvent) dewaxed waxy hydrocarbons,
or mixtures thereof, derived from different feed materials
including, feedstocks of mineral oil, non-mineral oil,
non-petroleum, 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, foots oil, wax from coal liquefaction or from
shale oil, or other suitable mineral oil, non-mineral oil,
non-petroleum, or natural source 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
hydrodewaxate or hydroisomerate base stocks and base oils.
[0044] 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.
[0045] 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
hydrodewaxing or hydroisomerization catalyst.
[0046] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed, or hydroisomerized/cat (or
solvent) dewaxed F-T material derived base stock(s) and/or base
oil(s), and other hydrodewaxed, or hydroisomerized/cat (or solvent)
dewaxed wax derived base stock(s) and/or base oil(s) are
characterized typically as having kinematic viscosities at
100.degree. C. of from about 2 mm.sup.2/s to about 50 mm.sup.2/s,
preferably from about 3 mm.sup.2/s to about 50 mm.sup.2/s, more
preferably from about 3.5 mm.sup.2/s to about 30 mm.sup.2/s, as
exemplified by a GTL base stock derived by the isodewaxing of F-T
wax, which has a kinematic viscosity of about 4 mm.sup.2/s at
100.degree. C. and a viscosity index of about 130 or greater.
Preferably the wax treatment process is hydrodewaxing carried out
in a process using a single hydrodewaxing catalyst. Reference
herein to Kinematic viscosity refers to a measurement made by ASTM
method D445.
[0047] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially hydrodewaxed, or hydroisomerized/cat (or
solvent) dewaxed F-T material derived base stock(s) and/or base
oil(s), and other hydrodewaxed, or hydroisomerized/cat (or solvent)
dewaxed wax-derived base stock(s) and/or base oil(s), which can be
used as base oil 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. In the present invention,
however, the GTL or other hydrodewaxed, or hydroisomerized/cat (or
solvent) dewaxed wax-derived base stock(s) and/or base oils used
are those having pour points of about -30.degree. C. or higher,
preferably about -25.degree. C. or higher, more preferably about
-20.degree. C. or higher. References herein to pour point refer to
measurement made by ASTM D97 and similar automated versions.
[0048] The GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially hydrodewaxed or hydroisomerized/cat (or
solvent) dewaxed F-T material derived base stock(s) and/or base
oils, and other such wax-derived base stock(s) and/or base oils
which are base oil components which can be used in 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, the
viscosity index of this/these base stock(s) and/or base oils may be
preferably 130 or greater, more preferably 135 or greater, and even
more preferably 140 or greater. For example, GTL base stock(s) that
derive 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.
[0049] In addition, the GTL base stock(s) and/or base oils are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stocks and/or 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/or base oil
obtained by the hydroisomerization/isodewaxing of F-T material,
especially F-T wax is essentially nil.
[0050] In a preferred embodiment, the GTL base stock(s) and/or base
oils comprises paraffinic materials that consist predominantly of
non-cyclic isoparaffins and only minor amounts of cycloparaffins.
These GTL base stock(s) and/or base oils typically comprise
paraffinic materials that consist of greater than 60 wt %
non-cyclic isoparaffins, preferably greater than 80 wt % non-cyclic
isoparaffins, more preferably greater than 85 wt % non-cyclic
isoparaffins, and most preferably greater than 90 wt % non-cyclic
isoparaffins.
[0051] Useful compositions of GTL base stock(s) and/or base oil(s),
hydrodewaxed or hydroisomerized/cat (or solvent) dewaxed F-T
material derived base stock(s) and/or base oil(s), and wax-derived
hydrodewaxed, or hydroisomerized/cat (or solvent) dewaxed base
stock(s) and/or base oil(s), such as wax isomerates or
hydrodewaxates, are recited in U.S. Pat. Nos. 6,080,301; 6,090,989,
and 6,165,949 for example.
[0052] Wax hydrodewaxate or hydroisomerate base stocks and/or base
oils derived from waxy feeds which are also suitable for use in
this invention in combination with the aforesaid GTL base stocks
and/or base oils, are paraffinic fluids of lubricating viscosity
derived from hydrodewaxed or hydroisomerized/catalytic (or solvent)
dewaxed 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.
[0053] As used herein, the following terms have the indicated
meanings: [0054] a) "wax"--hydrocarbonaceous material having a high
pour point, typically existing as a solid at room temperature,
i.e., at a temperature in the range from about 15.degree. C. to
25.degree. C., and consisting predominantly of paraffinic
materials; [0055] b) "paraffinic" material: any saturated
hydrocarbons, such as alkanes. Paraffinic materials may include
linear alkanes, branched alkanes (isoparaffins), cycloalkanes
(cycloparaffins; mono-ring and/or multi-ring), and branched
cycloalkanes; [0056] c) "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; [0057] d) "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; [0058]
e) "catalytic dewaxing": a conventional catalytic process in which
normal paraffins (wax) and/or waxy hydrocarbons, e.g., slightly
branched isoparaffins, are converted by cracking/fragmentation into
lower molecular weight species to insure that the final oil product
(base stock or base oil) has the desired product pour point; [0059]
f) "hydroisomerization" (or isomerization): a catalytic process in
which normal paraffins (wax) and/or slightly branched iso-paraffins
are converted by rearrangement/isomerization into branched or more
branched iso-paraffins (the isomerate from such a process possibly
requiring a subsequent additional wax removal step to ensure that
the final oil product (base stock or base oil) has the desired
product pour point); [0060] g) "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. [0061] h)
"hydrodewaxing": (e.g., ISODEWAXING.RTM. of Chevron or MSDWM of
Exxon Mobil corporation) a very selective catalytic process which
in a single step or by use of a single catalyst or catalyst mixture
effects conversion of wax by isomerization/rearrangement of the
n-paraffins and slightly branched isoparaffins into more heavily
branched isoparaffins, the resulting product not requiring a
separate conventional catalytic or solvent dewaxing step to meet
the desired product pour point; [0062] i) the terms
"hydroisomerate", "isomerate", "catalytic dewaxate", and
"hydrodewaxate" refer to the products produced by the respective
processes, unless otherwise specifically indicated.
[0063] Thus the term "hydroisomerization/cat dewaxing" is used to
refer to catalytic processes which have the combined effect of
converting normal paraffins and/or waxy hydrocarbons by
rearrangement/isomerization, into more branched iso-paraffins,
followed by (1) catalytic dewaxing to reduce the amount of any
residual n-paraffins or slightly branched iso-paraffins present in
the isomerate by cracking/fragmentation or by (2) hydrodewaxing to
effect further isomerization and very selective catalytic dewaxing
of the isomerate, to reduce the product pour point. When the term
(or solvent), is included in the recitation, the process described
involves hydroisomerization followed by solvent dewaxing which
effects the physical separation of wax from the hydroisomerate so
as to reduce the product pour point.
[0064] The term GTL base stock and/or base oil and/or wax
hydrodewaxate or hydroisomerate base stock and/or base oil as used
herein and in the claims is to be understood as embracing
individual fractions of GTL base stock and/or base oil and/or of
wax-derived hydrodewaxed or hydroisomerized/cat (or solvent)
dewaxed base stock and/or base oil as recovered in the production
process, mixtures of two or more GTL base stocks and/or base oil(s)
fractions and/or wax-derived hydrodewaxed, or hydroisomerized/cat
(or solvent) dewaxed base stock(s) and/or base oil(s) fractions, as
well as mixtures of one or two or more low viscosity GTL base
stock(s) and/or base oil(s) fraction(s) and/or wax-derived
hydrodewaxed, or hydroisomerized/cat (or solvent) dewaxed base
stock(s) and/or base oil(s) fraction(s) with one, two or more
higher viscosity GTL base stock(s) and/or base oil(s) fraction(s)
and/or wax-derived hydrodewaxed, or hydroisomerized/cat (or
solvent) dewaxed base stock(s) and/or base oil(s) fraction(s) to
produce a dumbbell blend wherein the blend exhibits a kinematic
viscosity within the aforesaid recited range.
[0065] In a preferred embodiment, the GTL material, from which the
GTL base stock(s) and/or base oil(s) is/are derived is an 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 an F-T
catalyst comprising a catalytic cobalt component to provide a high
Schultz-Flory kinetic alpha for producing the more desirable higher
molecular weight paraffins. This process is also well known to
those skilled in the art.
[0066] In an 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 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 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, (e.g., 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. The term "C.sub.5+" is used herein to refer
to hydrocarbons with a carbon number of greater than 4, but does
not imply that material with carbon number 5 has to be present.
Similarly other ranges quoted for carbon number do not imply that
hydrocarbons having the limit values of the carbon number range
have to be present, or that every carbon number in the quoted range
is present. 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 5,545,674.
[0067] As set forth above, the waxy feed from which the base
stock(s) and/or base oil(s) is/are derived is a wax or waxy feed
from mineral oil, non-mineral oil, non-petroleum, or other natural
source, especially slack wax, or GTL material, preferably 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 after
isomerization/isodewaxing, some of the isomerate/isodewaxate will
also be hydrocracked to lower boiling material during the
conventional catalytic dewaxing. Hence, it is preferred that the
end boiling point of the waxy feed be above 1050.degree. F.
(1050.degree. F.+).
[0068] When a boiling range is quoted herein it defines the lower
and/or upper distillation temperature used to separate the
fraction. Unless specifically stated (for example, by specifying
that the fraction boils continuously or constitutes the entire
range) the specification of a boiling range does not require any
material at the specified limit has to be present, rather it
excludes material boiling outside that range.
[0069] The waxy feed preferably comprises the entire
650-750.degree. F.+ fraction formed by the hydrocarbon synthesis
process, having an initial cut point between 650.degree. F. and
750.degree. F. determined by the practitioner and an end point,
preferably above 1050.degree. F., determined by the catalyst and
process variables employed by the practitioner for the synthesis.
Such fractions are referred to herein as "650-750.degree.
F.+fractions". By contrast, "650-750.degree. F..sup.- fractions"
refers to a fraction with an unspecified initial cut point and an
end point somewhere between 650.degree. F. and 750.degree. F. 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.
[0070] The process of making the lubricant oil base stocks from
waxy stocks, e.g., slack wax or F-T wax, may be characterized as an
isomerization 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
or 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 prehydrotreatment for the
removal of oxygenates while others may benefit from oxygenates
treatment. The hydroisomerization or 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.l.l..sup.-1 (56 to 19,660 SCF/bbl) and the space velocity of the
feedstock typically ranges from about 0.1 to 20 LHSV, preferably
0.1 to 10 LHSV.
[0071] Following any needed hydrodenitrogenation 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.
[0072] Other isomerization catalysts and processes for
hydrocracking, hydrodewaxing, or hydroisomerizing 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; 5,200,382; 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 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.
[0073] 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, and 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.
[0074] 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 waxy feed can be fed over
the hydrodewaxing catalyst comprising 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 stock and/or base oil products may be
obtained. Catalyst ZSM-48 is described in U.S. Pat. No. 5,075,269.
The use of the Group VIII metal loaded ZSM-48 family of catalysts,
preferably platinum on ZSM-48, in the hydroisomerization of the
waxy feedstock eliminates the need for any subsequent, separate
dewaxing step, and is preferred.
[0075] A dewaxing step, when needed, may be accomplished using one
or more of solvent dewaxing, catalytic dewaxing or hydrodewaxing
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.
Autorefrigerative dewaxing using low molecular weight hydrocarbons,
such as propane, can also be used in which the hydroisomerate is
mixed with, e.g., 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
fractionation of the 650-750.degree. F.+ material into the desired
base stocks.
[0076] 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.
[0077] GTL base stock(s) and/or base oil(s), hydrodewaxed, or
hydroisomerized/cat (or solvent) dewaxed wax-derived base stock(s)
and/or base oil(s), have a beneficial kinematic viscosity advantage
over conventional API Group II and Group III base stocks, and so
may be very advantageously used with the instant invention. Such
GTL base stock(s) and/or base oil(s) can have significantly higher
kinematic viscosities, up to about 20-50 mm.sup.2/s at 100.degree.
C., whereas by comparison commercial Group II base oils can have
kinematic viscosities, up to about 15 mm.sup.2/s at 100.degree. C.,
and commercial Group III base oils can have kinematic viscosities,
up to about 10 mm.sup.2/s at 100.degree. C. The higher kinematic
viscosity range of GTL base stock(s) and/or base oil(s), 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.
[0078] In the present invention the GTL base stock(s) and/or base
oil(s) can constitute all or part of the base stock oil to which
the PAO is added.
[0079] The GTL base stock(s) and/or base oil(s) can constitute from
5 to 100%, preferably 40 to 100%, more preferably 70 to 100%, still
more preferably 90 to 100% by weight of the total of the base oil,
the amount employed being left to the practitioner in response to
the requirements of the finished lubricant, the balance being
mineral oil stocks, e.g., Group I, Group II, Group III stocks as
defined by API base stock classification, and/or wax hydrodewaxate
or hydroisomerate derived from waxes or waxy feeds derived from
mineral oil, non-mineral oil or natural sources, e.g., slack wax,
foot oil, waxy raffinate, wax from coal liquefaction or shale oil
processing, etc.
[0080] These GTL, and optionally other base oils including
hydrodewaxate or hydroisomerate derived from the waxes or waxy
feeds, and polyolefin fluid blends can be also mixed with other
desirable components to further improve the properties. These other
components include many of the Group V base stocks as defined by
API base stock classification. Typical group V base stocks include
esters fluids, alkylaromatic fluids, polyalkylene glycol fluids,
etc.
[0081] A preferred GTL liquid hydrocarbon composition is one
comprising paraffinic hydrocarbon components in which the extent of
branching, as measured by the percentage of methyl hydrogens (BI),
and the proximity of branching, as measured by the percentage of
recurring methylene carbons which are four or more carbons removed
from an end group or branch (CH.sub.2.gtoreq.4), are such that: (a)
BI-0.5(CH.sub.2.gtoreq.4)>15; and (b) BI+0.85
(CH.sub.2.gtoreq.4)<45 as measured over said liquid hydrocarbon
composition as a whole.
[0082] The preferred GTL base stock and/or base oil can be further
characterized, if necessary, as having less than 0.1 wt % aromatic
hydrocarbons, less than 20 wppm nitrogen containing compounds, less
than 20 wppm sulfur containing compounds, a pour point of less than
-18.degree. C., preferably less than -30.degree. C., a preferred
BI.gtoreq.25.4 and (CH.sub.2.gtoreq.4)<22.5. They have a nominal
boiling point of 370.degree. C..sup.+, on average they average
fewer than 10 hexyl or longer branches per 100 carbon atoms and on
average have more than 16 methyl branches per 100 carbon atoms.
They also can be characterized by a combination of dynamic
viscosity, as measured by CCS at -40.degree. C., and kinematic
viscosity, as measured at 100.degree. C. represented by the
formula: DV (at -40.degree. C.)<2900 (KV at 100.degree.
C.)-7000.
[0083] The preferred GTL base stock and/or base oil is also
characterized as comprising a mixture of branched paraffins
characterized in that the lubricant base oil contains at least 90%
of a mixture of branched paraffins, wherein said branched paraffins
are paraffins having a carbon chain length of about C.sub.20 to
about C.sub.40, a molecular weight of about 280 to about 562, a
boiling range of about 650.degree. F. to about 1050.degree. F., and
wherein said branched paraffins contain up to four alkyl branches
and wherein the free carbon index of said branched paraffins is at
least about 3.
[0084] In the above the Branching Index (BI), Branching Proximity
(CH.sub.2.gtoreq.4), and Free Carbon Index (FCI) are determined as
follows:
Branching Index
[0085] A 359.88 MHz 1H solution NMR spectrum is obtained on a
Bruker 360 MHz AMX spectrometer using 10% solutions in CDCl.sub.3.
TMS is the internal chemical shift reference. CDCl.sub.3 solvent
gives a peak located at 7.28. All spectra are obtained under
quantitative conditions using 90 degree pulse (10.9 .mu.s), a pulse
delay time of 30 s, which is at least five times the longest
hydrogen spin-lattice relaxation time (T.sub.1), and 120 scans to
ensure good signal-to-noise ratios.
[0086] H atom types are defined according to the following regions:
[0087] 9.2-6.2 ppm hydrogens on aromatic rings; [0088] 6.2-4.0 ppm
hydrogens on olefinic carbon atoms; [0089] 4.0-2.1 ppm benzylic
hydrogens at the .alpha.-position to aromatic rings; [0090] 2.1-1.4
ppm paraffinic CH methine hydrogens; [0091] 1.4-1.05 ppm paraffinic
CH.sub.2 methylene hydrogens; [0092] 1.05-0.5 ppm paraffinic
CH.sub.3 methyl hydrogens.
[0093] The branching index (BI) is calculated as the ratio in
percent of non-benzylic methyl hydrogens in the range of 0.5 to
1.05 ppm, to the total non-benzylic aliphatic hydrogens in the
range of 0.5 to 2.1 ppm.
Branching Proximity (CH.sub.2.gtoreq.4)
[0094] A 90.5 MHz.sup.3CMR single pulse and 135 Distortionless
Enhancement by Polarization Transfer (DEPT) NMR spectra are
obtained on a Brucker 360 MHzAMX spectrometer using 10% solutions
in CDCL.sub.3. TMS is the internal chemical shift reference.
CDCL.sub.3 solvent gives a triplet located at 77.23 ppm in the
.sup.13C spectrum. All single pulse spectra are obtained under
quantitative conditions using 45 degree pulses (6.3 .mu.s), a pulse
delay time of 60 s, which is at least five times the longest carbon
spin-lattice relaxation time (T.sub.1), to ensure complete
relaxation of the sample, 200 scans to ensure good signal-to-noise
ratios, and WALTZ-16 proton decoupling.
[0095] The C atom types CH.sub.3, CH.sub.2, and CH are identified
from the 135 DEPT .sup.13C NMR experiment. A major CH.sub.2
resonance in all .sup.13C NMR spectra at .apprxeq.29.8 ppm is due
to equivalent recurring methylene carbons which are four or more
removed from an end group or branch (CH2>4). The types of
branches are determined based primarily on the .sup.13C chemical
shifts for the methyl carbon at the end of the branch or the
methylene carbon one removed from the methyl on the branch.
[0096] Free Carbon Index (FCI). The FCI is expressed in units of
carbons, and is a measure of the number of carbons in an
isoparaffin that are located at least 5 carbons from a terminal
carbon and 4 carbons way from a side chain. Counting the terminal
methyl or branch carbon as "one" the carbons in the FCI are the
fifth or greater carbons from either a straight chain terminal
methyl or from a branch methane carbon. These carbons appear
between 29.9 ppm and 29.6 ppm in the carbon-13 spectrum. They are
measured as follows: [0097] a) calculate the average carbon number
of the molecules in the sample which is accomplished with
sufficient accuracy for lubricating oil materials by simply
dividing the molecular weight of the sample oil by 14 (the formula
weight of CH.sub.2); [0098] b) divide the total carbon-13 integral
area (chart divisions or area counts) by the average carbon number
from step a. to obtain the integral area per carbon in the sample;
[0099] c) measure the area between 29.9 ppm and 29.6 ppm in the
sample; and [0100] d) divide by the integral area per carbon from
step b. to obtain FCI.
[0101] Branching measurements can be performed using any Fourier
Transform NMR spectrometer. Preferably, the measurements are
performed using a spectrometer having a magnet of 7.0 T or greater.
In all cases, after verification by Mass Spectrometry, UV or an NMR
survey that aromatic carbons were absent, the spectral width was
limited to the saturated carbon region, about 0-80 ppm vs. TMS
(tetramethylsilane). Solutions of 15-25 percent by weight in
chloroform-d1 were excited by 45 degrees pulses followed by a 0.8
sec acquisition time. In order to minimize non-uniform intensity
data, the proton decoupler was gated off during a 10 sec delay
prior to the excitation pulse and on during acquisition. Total
experiment times ranged from 11-80 minutes. The DEPT and APT
sequences were carried out according to literature descriptions
with minor deviations described in the Varian or Bruker operating
manuals.
[0102] DEPT is Distortionless Enhancement by Polarization Transfer.
DEPT does not show quaternaries. The DEPT 45 sequence gives a
signal for all carbons bonded to protons. DEPT 90 shows CH carbons
only. DEPT 135 shows CH and CH.sub.3 up and CH.sub.2 180 degrees
out of phase (down). APT is Attached Proton Test. It allows all
carbons to be seen, but if CH and CH.sub.3 are up, then
quaternaries and CH.sub.2 are down. The sequences are useful in
that every branch methyl should have a corresponding CH and the
methyls are clearly identified by chemical shift and phase. The
branching properties of each sample are determined by C-13 NMR
using the assumption in the calculations that the entire sample is
isoparaffinic. Corrections are not made for n-paraffins or
cyclo-paraffins, which may be present in the oil samples in varying
amounts. The cycloparaffins content is measured using Field
Ionization Mass Spectroscopy (FIMS).
[0103] GTL base stock(s) and/or base oil(s), and hydrodewaxed, or
hydroisomerized/cat (or solvent) dewaxed wax base stock(s) and/or
base oil(s), for example, hydroisomerized or hydrodewaxed waxy
synthesized hydrocarbon, e.g., Fischer-Tropsch waxy hydrocarbon
base stock(s) and/or base oil(s) are of low or zero sulfur and
phosphorus content. There is a movement among original equipment
manufacturers and oil formulators to produce formulated oils of
ever increasingly reduced sulfated ash, phosphorus and sulfur
content to meet ever increasingly restrictive environmental
regulations. Such oils, known as low SAPS oils, would rely on the
use of base oils which themselves, inherently, are of low or zero
initial sulfur and phosphorus content. Such oils when used as base
oils can be formulated with additives. Even if the additive or
additives included in the formulation contain sulfur and/or
phosphorus the resulting formulated lubricating oils will be lower
or low SAPS oils as compared to lubricating oils formulated using
conventional mineral oil base stocks.
[0104] Low SAPS formulated oils for vehicle engines (both spark
ignited and compression ignited) will have a sulfur content of 0.7
wt % or less, preferably 0.6 wt % or less, more preferably 0.5 wt %
or less, most preferably 0.4 wt % or less, an ash content of 1.2 wt
% or less, preferably 0.8 wt % or less, more preferably 0.4 wt % or
less, and a phosphorus content of 0.18% or less, preferably 0.1 wt
% or less, more preferably 0.09 wt % or less, most preferably 0.08
wt % or less, and in certain instances, even preferably 0.05 wt %
or less.
[0105] These mostly paraffinic GTL base stock(s) and/or base
oil(s), when blended with the polyolefin fluids yield unique blend
compositions. These blend compositions have unexpected high
thermal, oxidative stability and excellent viscometrics (wide
viscosity range, high VI and low pour point). This blend
composition is characterized by wide range of kinematic viscosity
(from 2 mm.sup.2/s to 1000 mm.sup.2/s at 100.degree. C. or 3
mm.sup.2/s to 50,000 mm.sup.2/s at 40.degree. C., high VI and low
pour points) and low amount of any other undesirable
components--low S, N, low aromatics, low cyclic hydrocarbons or
naphthenic components. Such compositions are not previously
known.
[0106] These mixtures of GTL base stock(s) and/or base oil(s) with
polyolefin fluids may be blended with effective amounts of one or
more suitable additives to form lubricant compositions.
[0107] Examples of typical additives include, but are not limited
to, oxidation inhibitors, antioxidants, dispersants, detergents,
corrosion inhibitors, rust inhibitors, metal deactivators,
anti-wear agents, extreme pressure additives, anti-seizure agents,
pour point depressants, wax modifiers, other viscosity index
improvers, other viscosity modifiers, fluid-loss additives, seal
compatibility agents, friction modifiers, lubricity agents,
anti-staining agents, chromophoric agents, defoamants,
demulsifiers, emulsifiers, densifiers, wetting agents, gelling
agents, tackiness agents, colorants, and others. For a review of
many commonly used additives, see Klamann in Lubricants and Related
Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN 0-89573-177-0.
Reference is also made to "Lubricant Additives" by M. W. Ranney,
published by Noyes Data Corporation of Parkridge, N.J. (1973).
[0108] Finished lubricants comprise the lubricant base stock or
base oil, plus at least one performance additive.
[0109] The types and quantities of performance additives used in
combination with the instant invention in lubricant compositions
are not limited by the examples shown herein as illustrations.
Antiwear and EP Additives
[0110] Many lubricating oils require the presence of antiwear
and/or extreme pressure (EP) additives in order to provide adequate
antiwear protection. Increasingly specifications for, e.g., engine
oil performance have exhibited a trend for improved antiwear
properties of the oil. Antiwear and extreme EP additives perform
this role by reducing friction and wear of metal parts.
[0111] While there are many different types of antiwear additives,
for several decades the principal antiwear additive for internal
combustion engine crankcase oils is a metal alkylthiophosphate and
more particularly a metal dialkyldithio-phosphate in which the
primary metal constituent is zinc, or zinc dialkyldithio-phosphate
(ZDDP). ZDDP compounds generally are of the formula
Zn[SP(S)(OR'')(OR.sup.2)].sub.2 where R.sup.1 and R.sup.2 are
C.sub.1-C.sub.18 alkyl groups, preferably C.sub.2-C.sub.12 alkyl
groups. These alkyl groups may be straight chain or branched. The
ZDDP is typically used in amounts of from about 0.4 to 1.4 wt % of
the total lube oil composition, although more or less can often be
used advantageously.
[0112] However, it is found that the phosphorus from these
additives has a deleterious effect on the catalyst in catalytic
converters and also on oxygen sensors in automobiles. One way to
minimize this effect is to replace some or all of the ZDDP with
phosphorus-free antiwear additives.
[0113] A variety of non-phosphorous additives are also used as
antiwear additives. Sulfurized olefins are useful as antiwear and
EP additives. Sulfur-containing olefins can be prepared by
sulfinurization or various organic materials including aliphatic,
arylaliphatic or alicyclic olefinic hydrocarbons containing from
about 3 to 30 carbon atoms, preferably 3-20 carbon atoms. The
olefinic compounds contain at least one non-aromatic double bond.
Such compounds are defined by the formula
R.sup.3R.sup.4C.dbd.CR.sup.5R.sup.6
[0114] where each of R.sup.3-R.sup.6 are independently hydrogen or
a hydrocarbon radical. Preferred hydrocarbon radicals are alkyl or
alkenyl radicals. Any two of R.sup.3-R.sup.6 may be connected so as
to form a cyclic ring. Additional information concerning sulfurized
olefins and their preparation can be found in U.S. Pat. No.
4,941,984, incorporated by reference herein in its entirety.
[0115] The use of polysulfides of thiophosphorus acids and
thiophosphorus acid esters as lubricant additives is disclosed in
U.S. Pat. Nos. 2,443,264; 2,471,115; 2,526,497; and 2,591,577.
Addition of phosphorothionyl disulfides as an antiwear,
antioxidant, and EP additive is disclosed in U.S. Pat. No.
3,770,854. Use of alkylthiocarbamoyl compounds
(bis(dibutyl)thiocarbamoyl, for example) in combination with a
molybdenum compound (oxymolybdenum diisopropyl-phosphorodithioate
sulfide, for example) and a phosphorous ester (dibutyl hydrogen
phosphite, for example) as antiwear additives in lubricants is
disclosed in U.S. Pat. No. 4,501,678. U.S. Pat. No. 4,758,362
discloses use of a carbamate additive to provide improved antiwear
and extreme pressure properties. The use of thiocarbamate as an
antiwear additive is disclosed in U.S. Pat. No. 5,693,598.
Thiocarbamate/molybdenum complexes such as moly-sulfur alkyl
dithiocarbamate trimer complex (R.dbd.C.sub.8-C.sub.18 alkyl) are
also useful antiwear agents. The use or addition of such materials
should be kept to a minimum if the object is to produce low SAP
formulations.
[0116] Esters of glycerol may be used as antiwear agents. For
example, mono-, di, and tri-oleates, mono-palmitates and
mono-myristates may be used.
[0117] ZDDP is combined with other compositions that provide
antiwear properties. U.S. Pat. No. 5,034,141 discloses that a
combination of a thiodixanthogen compound (octylthiodixanthogen,
for example) and a metal thiophosphate (ZDDP, for example) can
improve antiwear properties. U.S. Pat. No. 5,034,142 discloses that
use of a metal alkyoxyalkylxanthate (nickel ethoxyethylxanthate,
for example) and a dixanthogen (diethoxyethyl dixanthogen, for
example) in combination with ZDDP improves antiwear properties.
[0118] Preferred antiwear additives include phosphorus and sulfur
compounds such as zinc dithiophosphates and/or sulfur, nitrogen,
boron, molybdenum phosphorodithioates, molybdenum dithiocarbamates
and various organo-molybdenum derivatives including heterocyclics,
for example dimercaptothiadiazoles, mercaptobenzothiadiazoles,
triazines, and the like, alicyclics, amines, alcohols, esters,
diols, triols, fatty amides and the like can also be used. Such
additives may be used in an amount of about 0.01 to 6 wt %,
preferably about 0.01 to 4 wt %. ZDDP-like compounds provide
limited hydroperoxide decomposition capability, significantly below
that exhibited by compounds disclosed and claimed in this patent
and can therefore be eliminated from the formulation or, if
retained, kept at a minimal concentration to facilitate production
of low SAP formulations.
Viscosity Index Improvers
[0119] Viscosity index improvers (also known as VI improvers,
viscosity modifiers, and viscosity improvers) provide lubricants
with high and low temperature operability. These additives impart
shear stability at elevated temperatures and acceptable viscosity
at low temperatures.
[0120] Suitable viscosity index improvers include high molecular
weight hydrocarbons, polyesters and viscosity index improver
dispersants that function as both a viscosity index improver and a
dispersant. Typical molecular weights of these polymers are between
about 10,000 to 1,000,000, more typically about 20,000 to 500,000,
and even more typically between about 50,000 and 200,000.
[0121] Examples of suitable viscosity index improvers are polymers
and copolymers of methacrylate, butadiene, olefins, or alkylated
styrenes. Polyisobutylene is a commonly used viscosity index
improver. Another suitable viscosity index improver is
polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity index improvers
include copolymers of ethylene and propylene, hydrogenated block
copolymers of styrene and isoprene, and polyacrylates (copolymers
of various chain length acrylates, for example). Specific examples
include styrene-isoprene or styrene-butadiene based polymers of
50,000 to 200,000 molecular weight.
[0122] Viscosity index improvers may be used in an amount of about
0.01 to 8 wt %, preferably about 0.01 to 4 wt %.
Antioxidants
[0123] Antioxidants retard the oxidative degradation of base oils
during service. Such degradation may result in deposits on metal
surfaces, the presence of sludge, or a viscosity increase in the
lubricant. One skilled in the art knows a wide variety of oxidation
inhibitors that are useful in lubricating oil compositions. See,
Klamann in Lubricants and Related Products, op cite, and U.S. Pat.
Nos. 4,798,684 and 5,084,197, for example.
[0124] Useful antioxidants include hindered phenols. These phenolic
anti-oxidants may be ashless (metal-free) phenolic compounds or
neutral or basic metal salts of certain phenolic compounds. Typical
phenolic antioxidant compounds are the hindered phenolics which are
the ones which contain a sterically hindered hydroxyl group, and
these include those derivatives of dihydroxy aryl compounds in
which the hydroxyl groups are in the o- or p-position to each
other. Typical phenolic antioxidants include the hindered phenols
substituted with C.sub.6+ alkyl groups and the alkylene coupled
derivatives of these hindered phenols. Examples of phenolic
materials of this type 2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl
phenol; 2-t-butyl-4-dodecyl phenol; 2,6-di-t-butyl-4-heptyl phenol;
2,6-di-t-butyl-4-dodecyl phenol; 2-methyl-6-t-butyl-4-heptyl
phenol; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.
Bis-phenolic antioxidants may also be advantageously used in
combination with the instant invention. Examples of ortho-coupled
phenols include: 2,2'-bis(4-heptyl-6-t-butyl-phenol);
2,2'-bis(4-octyl-6-t-butyl-phenol); and
2,2'-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0125] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: alkylated and non-alkylated aromatic amines
such as aromatic monoamines of the formula R.sup.8R.sup.9R.sup. N
where R.sup.8 is an aliphatic, aromatic or substituted aromatic
group, R.sup.9 is an aromatic or a substituted aromatic group, and
R.sup.10 is H, alkyl, aryl or R.sup.11S(O).sub.xR.sup.12 where
R.sup.11 is an alkylene, alkenylene, or aralkylene group, R.sup.12
is a higher alkyl group, or an alkenyl, aryl, or alkaryl group, and
x is 0, 1 or 2. The aliphatic group R.sup.8 may contain from 1 to
about 20 carbon atoms, and preferably contains from about 6 to 12
carbon atoms. The aliphatic group is a saturated aliphatic group.
Preferably, both R.sup.8 and R.sup.9 are aromatic or substituted
aromatic groups, and the aromatic group may be a fused ring
aromatic group such as naphthyl. Aromatic groups R.sup.8 and
R.sup.9 may be joined together with other groups such as S.
[0126] Typical aromatic amines antioxidants have alkyl substituent
groups of at least about 6 carbon atoms. Examples of aliphatic
groups include hexyl, heptyl, octyl, nonyl, and decyl. Generally,
the aliphatic groups will not contain more than about 14 carbon
atoms. The general types of amine antioxidants useful in the
present compositions include diphenylamines, phenyl naphthylamines,
phenothiazines, imidodibenzyls and diphenyl phenylene diamines.
Mixtures of two or more aromatic amines are also useful. Polymeric
amine antioxidants can also be used. Particular examples of
aromatic amine antioxidants useful in the present invention
include: p,p'-dioctyldiphenylamine;
t-octylphenyl-alpha-naphthylamine; phenyl-alphanaphthylamine; and
p-octylphenyl-alpha-naphthylamine.
[0127] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0128] Another class of antioxidant used in lubricating oil
compositions is oil-soluble copper compounds. Any oil-soluble
suitable copper compound may be blended into the lubricating oil.
Examples of suitable copper antioxidants include copper
dihydrocarbyl thio- or dithio-phosphates and copper salts of
carboxylic acid (naturally occurring or synthetic). Other suitable
copper salts include copper dithiacarbamates, sulphonates,
phenates, and acetylacetonates. Basic, neutral, or acidic copper
Cu(I) and or Cu(II) salts derived from alkenyl succinic acids or
anhydrides are know to be particularly useful.
[0129] Preferred antioxidants include hindered phenols, arylamines.
These antioxidants may be used individually by type or in
combination with one another. Such additives may be used in an
amount of about 0.01 to 5 wt %, preferably about 0.01 to 1.5 wt %,
more preferably zero to less than 1.5 wt %, most preferably
zero.
Detergents
[0130] Detergents are commonly used in lubricating compositions. A
typical detergent is an anionic material that contains a long chain
hydrophobic portion of the molecule and a smaller anionic or
oleophobic hydrophilic portion of the molecule. The anionic portion
of the detergent is typically derived from an organic acid such as
a sulfur acid, carboxylic acid, phosphorous acid, phenol, or
mixtures thereof. The counterion is typically an alkaline earth or
alkali metal.
[0131] Salts that contain a substantially stochiometric amount of
the metal are described as neutral salts and have a total base
number (TBN, as measured by ASTM D2896) of from 0 to 80. Many
compositions are overbased, containing large amounts of a metal
base that is achieved by reacting an excess of a metal compound (a
metal hydroxide or oxide, for example) with an acidic gas (such as
carbon dioxide). Useful detergents can be neutral, mildly
overbased, or highly overbased.
[0132] It is desirable for at least some detergent to be overbased.
Overbased detergents help neutralize acidic impurities produced by
the combustion process and become entrapped in the oil. Typically,
the overbased material has a ratio of metallic ion to anionic
portion of the detergent of about 1.05:1 to 50:1 on an equivalent
basis. More preferably, the ratio is from about 4:1 to about 25:1.
The resulting detergent is an overbased detergent that will
typically have a TBN of about 150 or higher, often about 250 to 450
or more. Preferably, the overbasing cation is sodium, calcium, or
magnesium. A mixture of detergents of differing TBN can be used in
the present invention.
[0133] Preferred detergents include the alkali or alkaline earth
metal salts of sulfonates, phenates, carboxylates, phosphates, and
salicylates.
[0134] Sulfonates may be prepared from sulfonic acids that are
typically obtained by sulfonation of alkyl substituted aromatic
hydrocarbons. Hydrocarbon examples include those obtained by
alkylating benzene, toluene, xylene, naphthalene, biphenyl and
their halogenated derivatives (chlorobenzene, chlorotoluene, and
chloronaphthalene, for example). The alkylating agents typically
have about 3 to 70 carbon atoms. The alkaryl sulfonates typically
contain about 9 to about 80 carbon or more carbon atoms, more
typically from about 16 to 60 carbon atoms.
[0135] Klamann in Lubricants and Related Products, op cit discloses
a number of overbased metal salts of various sulfonic acids which
are useful as detergents and dispersants in lubricants. The book
entitled "Lubricant Additives", C. V. Smallheer and R. K. Smith,
published by the Lezius-Hiles Co. of Cleveland, Ohio (1967),
similarly discloses a number of overbased sulfonates that are
useful as dispersants/detergents.
[0136] Alkaline earth phenates are another useful class of
detergent. These detergents can be made by reacting alkaline earth
metal hydroxide or oxide (CaO, Ca(OH).sub.2, BaO, Ba(OH).sub.2,
MgO, Mg(OH).sub.2, for example) with an alkyl phenol or sulfurized
alkylphenol. Useful alkyl groups include straight chain or branched
C.sub.1-C.sub.30 alkyl groups, preferably, C.sub.4-C.sub.20.
Examples of suitable phenols include isobutylphenol,
2-ethylhexylphenol, nonylphenol, dodecyl phenol, and the like. It
should be noted that starting alkylphenols may contain more than
one alkyl substituent that are each independently straight chain or
branched. When a non-sulfurized alkylphenol is used, the sulfurized
product may be obtained by methods well known in the art. These
methods include heating a mixture of alkylphenol and sulfurizing
agent (including elemental sulfur, sulfur halides such as sulfur
dichloride, and the like) and then reacting the sulfurized phenol
with an alkaline earth metal base.
[0137] Metal salts of carboxylic acids are also useful as
detergents. These carboxylic acid detergents may be prepared by
reacting a basic metal compound with at least one carboxylic acid
and removing free water from the reaction product. These compounds
may be overbased to produce the desired TBN level. Detergents made
from salicylic acid are one preferred class of detergents derived
from carboxylic acids. Useful salicylates include long chain alkyl
salicylates. One useful family of compositions is of the formula
##STR1## where R is a hydrogen atom or an alkyl group having 1 to
about 30 carbon atoms, n is an integer from 1 to 4, and M is an
alkaline earth metal. Preferred R groups are alkyl chains of at
least C.sub.11, preferably C.sub.13 or greater. R may be optionally
substituted with substituents that do not interfere with the
detergent's function. M is preferably, calcium, magnesium, or
barium. More preferably, M is calcium.
[0138] Hydrocarbyl-substituted salicylic acids may be prepared from
phenols by the Kolbe reaction. See U.S. Pat. No. 3,595,791, which
is incorporated herein by reference in its entirety, for additional
information on synthesis of these compounds. The metal salts of the
hydrocarbyl-substituted salicylic acids may be prepared by double
decomposition of a metal salt in a polar solvent such as water or
alcohol.
[0139] Alkaline earth metal phosphates are also used as
detergents.
[0140] Detergents may be simple detergents or what is known as
hybrid or complex detergents. The latter detergents can provide the
properties of two detergents without the need to blend separate
materials. See U.S. Pat. No. 6,034,039 for example.
[0141] Preferred detergents include calcium phenates, calcium
sulfonates, calcium salicylates, magnesium phenates, magnesium
sulfonates, magnesium salicylates and other related components
(including borated detergents). Typically, the total detergent
concentration is about 0.01 to about 6.0 wt %, preferably, about
0.1 to 0.4 wt %.
Dispersant
[0142] During engine operation, oil-insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposition on metal surfaces. Dispersants
may be ashless or ash-forming in nature. Preferably, the dispersant
is ashless. So called ashless dispersants are organic materials
that form substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0143] Suitable dispersants typically contain a polar group
attached to a relatively high molecular weight hydrocarbon chain.
The polar group typically contains at least one element of
nitrogen, oxygen, or phosphorus. Typical hydrocarbon chains contain
50 to 400 carbon atoms.
[0144] Chemically, many dispersants may be characterized as
phenates, sulfonates, sulfurized phenates, salicylates,
naphthenates, stearates, carbamates, thiocarbamates, phosphorus
derivatives. A particularly useful class of dispersants are the
alkenylsuccinic derivatives, typically produced by the reaction of
a long chain substituted alkenyl succinic compound, usually a
substituted succinic anhydride, with a polyhydroxy or polyamino
compound. The long chain group constituting the oleophilic portion
of the molecule which confers solubility in the oil, is normally a
polyisobutylene group. Many examples of this type of dispersant are
well known commercially and in the literature. Exemplary U.S.
patents describing such dispersants are U.S. Pat. Nos. 3,172,892;
3,2145,707; 3,219,666; 3,316,177; 3,341,542; 3,444,170; 3,454,607;
3,541,012; 3,630,904; 3,632,511; 3,787,374 and 4,234,435. Other
types of dispersant are described in U.S. Pat. Nos. 3,036,003;
3,200,107; 3,254,025; 3,275,554; 3,438,757; 3,454,555; 3,565,804;
3,413,347; 3,697,574; 3,725,277; 3,725,480; 3,726,882; 4,454,059;
3,329,658; 3,449,250; 3,519,565; 3,666,730; 3,687,849; 3,702,300;
4,100,082; 5,705,458. A further description of dispersants may be
found, for example, in European Patent Application No. 471 071, to
which reference is made for this purpose.
[0145] Hydrocarbyl-substituted succinic acid compounds are popular
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful.
[0146] Succinimides are formed by the condensation reaction between
alkenyl succinic anhydrides and amines. Molar ratios can vary
depending on the polyamine. For example, the molar ratio of alkenyl
succinic anhydride to TEPA can vary from about 1:1 to about 5:1.
Representative examples are shown in U.S. Pat. Nos. 3,087,936;
3,172,892; 3,219,666; 3,272,746; 3,322,670; and 3,652,616,
3,948,800; and Canada Pat. No. 1,094,044.
[0147] Succinate esters are formed by the condensation reaction
between alkenyl succinic anhydrides and alcohols or polyols. Molar
ratios can vary depending on the alcohol or polyol used. For
example, the condensation product of an alkenyl succinic anhydride
and pentaerythritol is a useful dispersant.
[0148] Succinate ester amides are formed by condensation reaction
between alkenyl succinic anhydrides and alkanol amines. For
example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0149] The molecular weight of the alkenyl succinic anhydrides used
in the preceding paragraphs will typically range between 800 and
2,500. The above products can be post-reacted with various reagents
such as sulfur, oxygen, formaldehyde, carboxylic acids such as
oleic acid, and boron compounds such as borate esters or highly
borated dispersants. The dispersants can be borated with from about
0.1 to about 5 moles of boron per mole of dispersant reaction
product.
[0150] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Pat. No.
4,767,551, which is incorporated herein by reference. Process aids
and catalysts, such as oleic acid and sulfonic acids, can also be
part of the reaction mixture. Molecular weights of the alkylphenols
range from 800 to 2,500. Representative examples are shown in U.S.
Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365; 3,756,953;
3,798,165; and 3,803,039.
[0151] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this invention can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HN(R).sub.2 group-containing reactants.
[0152] Examples of high molecular weight alkyl-substituted
hydroxyaromatic compounds are polypropylphenol, polybutylphenol,
and other polyalkylphenols. These polyalkylphenols can be obtained
by the alkylation, in the presence of an alkylating catalyst, such
as BF.sub.3, of phenol with high molecular weight polypropylene,
polybutylene, and other polyalkylene compounds to give alkyl
substituents on the benzene ring of phenol having an average
600-100,000 molecular weight.
[0153] Examples of HN(R).sub.2 group-containing reactants are
alkylene polyamines, principally polyethylene polyamines. Other
representative organic compounds containing at least one
HN(R).sub.2 group suitable for use in the preparation of Mannich
condensation products are well known and include the mono- and
di-amino alkanes and their substituted analogs, e.g., ethylamine
and diethanol amine; aromatic diamines, e.g., phenylene diamine,
diamino naphthalenes; heterocyclic amines, e.g., morpholine,
pyrrole, pyrrolidine, imidazole, imidazolidine, and piperidine;
melamine and their substituted analogs.
[0154] Examples of alkylene polyamide reactants include
ethylenediamine, diethylene triamine, triethylene tetraamine,
tetraethylene pentaamine, pentaethylene hexamine, hexaethylene
heptaamine, heptaethylene octaamine, octaethylene nonaamine,
nonaethylene decamine, and decaethylene undecamine and mixture of
such amines having nitrogen contents corresponding to the alkylene
polyamines, in the formula H.sub.2N-(Z-NH--).sub.nH, mentioned
before, Z is a divalent ethylene and n is 1 to 10 of the foregoing
formula. Corresponding propylene polyamines such as propylene
diamine and di-, tri-, tetra-, penta-propylene tri-, tetra-, penta-
and hexaamines are also suitable reactants. The alkylene polyamines
are usually obtained by the reaction of ammonia and dihalo alkanes,
such as dichloro alkanes. Thus the alkylene polyamines obtained
from the reaction of 2 to 11 moles of ammonia with 1 to 10 moles of
dichloroalkanes having 2 to 6 carbon atoms and the chlorines on
different carbons are suitable alkylene polyamine reactants.
[0155] Aldehyde reactants useful in the preparation of the high
molecular products useful in this invention include the aliphatic
aldehydes such as formaldehyde (also as paraformaldehyde and
formalin), acetaldehyde and aldol (.beta.-hydroxybutyraldehyde).
Formaldehyde or a formaldehyde-yielding reactant is preferred.
[0156] Hydrocarbyl substituted amine ashless dispersant additives
are well known to one skilled in the art; see, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197, which are incorporated herein in their entirety by
reference.
[0157] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
about 500 to about 5000 or a mixture of such hydrocarbylene groups.
Other preferred dispersants include succinic acid-esters and
amides, alkylphenol-polyamine-coupled Mannich adducts, their capped
derivatives, and other related components. Such additives may be
used in an amount of about 0.1 to 20 wt %, preferably about 0.1 to
8 wt %.
Pour Point Depressants
[0158] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the compositions of the present
invention if desired. These pour point depressant may be added to
lubricating compositions of the present invention to lower the
minimum temperature at which the fluid will flow or can be poured.
Examples of suitable pour point depressants include
polymethacrylates, polyacrylates, polyarylamides, condensation
products of haloparaffin waxes and aromatic compounds, vinyl
carboxylate polymers, and terpolymers of dialkylfumarates, vinyl
esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2.721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof. Such additives may be
used in an amount of about 0.01 to 5 wt %, preferably about 0.01 to
1.5 wt %.
Corrosion Inhibitors
[0159] Corrosion inhibitors are used to reduce the degradation of
metallic parts that are in contact with the lubricating oil
composition. Suitable corrosion inhibitors include thiadiazoles.
See, for example, U.S. Pat. Nos. 2,719,125; 2,719,126; and
3,087,932, which are incorporated herein by reference in their
entirety. Such additives may be used in an amount of about 0.01 to
5 wt %, preferably about 0.01 to 1.5 wt %.
Seal Compatibility Additives
[0160] Seal compatibility agents help to swell elastomeric seals by
causing a chemical reaction in the fluid or physical change in the
elastomer. Suitable seal compatibility agents for lubricating oils
include organic phosphates, aromatic esters, aromatic hydrocarbons,
esters (butylbenzyl phthalate, for example), and polybutenyl
succinic anhydride. Such additives may be used in an amount of
about 0.01 to 3 wt %, preferably about 0.01 to 2 wt %.
Anti-Foam Agents
[0161] Anti-foam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical anti-foam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Anti-foam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers; usually
the amount of these additives combined is less than 1 percent and
often less than 0.1 percent.
Inhibitors and Antirust Additives
[0162] Antirust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. A wide variety of these are
commercially available; they are referred to in Klamann in
Lubricants and Related Products, op cit.
[0163] One type of antirust additive is a polar compound that wets
the metal surface preferentially, protecting it with a film of oil.
Another type of antirust additive absorbs water by incorporating it
in a water-in-oil emulsion so that only the oil touches the metal
surface. Yet another type of antirust additive chemically adheres
to the metal to produce a non-reactive surface. Examples of
suitable additives include zinc dithiophosphates, metal phenolates,
basic metal sulfonates, fatty acids and amines. Such additives may
be used in an amount of about 0.01 to 5 wt %, preferably about 0.01
to 1.5 wt %.
Friction Modifiers
[0164] A friction modifier is any material or materials that can
alter the coefficient of friction of a surface lubricated by any
lubricant or fluid containing such material(s). Friction modifiers,
also known as friction reducers, or lubricity agents or oiliness
agents, and other such agents that change the ability of base oils,
formulated lubricant compositions, or functional fluids, to modify
the coefficient of friction of a lubricated surface may be
effectively used in combination with the base oils or lubricant
compositions of the present invention if desired. Friction
modifiers that lower the coefficient of friction are particularly
advantageous in combination with the base oils and lube
compositions of this invention. Friction modifiers may include
metal-containing compounds or materials as well as ashless
compounds or materials, or mixtures thereof. Metal-containing
friction modifiers may include metal salts or metal-ligand
complexes where the metals may include alkali, alkaline earth, or
transition group metals. Such metal-containing friction modifiers
may also have low-ash characteristics. Transition metals may
include Mo, Sb, Sn, Fe, Cu, Zn, and others. Ligands may include
hydrocarbyl derivative of alcohols, polyols, glycerols, partial
ester glycerols, thiols, carboxylates, carbamates, thiocarbamates,
dithiocarbamates, phosphates, thiophosphates, dithiophosphates,
amides, imides, amines, thiazoles, thiadiazoles, dithiazoles,
diazoles, triazoles, and other polar molecular functional groups
containing effective amounts of O, N, S, or P, individually or in
combination. In particular, Mo-containing compounds can be
particularly effective such as for example Mo-dithiocarbamates,
Mo(DTC), Mo-dithiophosphates, Mo(DTP), Mo-amines, Mo (Am),
Mo-alcoholates, Mo-alcohol-amides, etc. See U.S. Pat. No.
5,824,627; U.S. Pat. No. 6,232,276; U.S. Pat. No. 6,153,564; U.S.
Pat. No. 6,143,701; U.S. Pat. No. 6,110,878; U.S. Pat. No.
5,837,657; U.S. Pat. No. 6,010,987; U.S. Pat. No. 5,906,968; U.S.
Pat. No. 6,734,150; U.S. Pat. No. 6,730,638; U.S. Pat. No.
6,689,725; U.S. Pat. No. 6,569,820; WO 99/66013; WO 99/47629; WO
98/26030.
[0165] Ashless friction modifiers may have also include lubricant
materials that contain effective amounts of polar groups, for
example, hydroxyl-containing hydrocarbyl base oils, glycerides,
partial glycerides, glyceride derivatives, and the like. Polar
groups in friction modifiers may include hydrocarbyl groups
containing effective amounts of O, N, S, or P, individually or in
combination. Other friction modifiers that may be particularly
effective include, for example, salts (both ash-containing and
ashless derivatives) of fatty acids, fatty alcohols, fatty amides,
fatty esters, hydroxyl-containing carboxylates, and comparable
synthetic long-chain hydrocarbyl acids, alcohols, amides, esters,
hydroxy carboxylates, and the like. In some instances fatty organic
acids, fatty amines, and sulfurized fatty acids may be used as
suitable friction modifiers.
[0166] Useful concentrations of friction modifiers may range from
about 0.01 wt % to 10-15 wt % or more, often with a preferred range
of about 0.1 wt % to 5 wt %. Concentrations of
molybdenum-containing materials are often described in terms of Mo
metal concentration. Advantageous concentrations of Mo may range
from about 10 ppm to 3000 ppm or more, and often with a preferred
range of about 20-2000 ppm, and in some instances a more preferred
range of about 30-1000 ppm. Friction modifiers of all types may be
used alone or in mixtures with the materials of this invention.
Often mixtures of two or more friction modifiers, or mixtures of
friction modifier(s) with alternate surface active material(s), are
also desirable.
Typical Additive Amounts
[0167] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
invention are shown in Table 1 below.
[0168] Note that many of the additives are shipped from the
manufacturer and used with a certain amount of base oil solvent in
the formulation. Accordingly, the weight amounts in the table
below, as well as other amounts mentioned in this patent, are
directed to the amount of active ingredient (that is the
non-solvent portion of the ingredient). The wt % indicated below
are based on the total weight of the lubricating oil composition.
TABLE-US-00001 TABLE 1 Typical Amounts of Various Lubricant Oil
Components Approximate Approximate Compound Wt % (Useful) Wt %
(Preferred) Detergent 0.01-6 0.01-4 Dispersant 0.1-20 0.1-8
Friction Reducer 0.01-5 0.01-1.5 Supplementary 0.0-40 0.01-30, more
Viscosity Index Improver preferably 0.01-15 Antioxidant 0.0-5
0.0-1.5 Corrosion Inhibitor 0.01-5 0.01-1.5 Anti-wear Additive
0.01-6 0.01-4 Pour Point Depressant 0.0-5 0.01-1.5 Anti-foam Agent
0.001-3 0.001-0.15 Base Oil Balance Balance
EXAMPLES
[0169] GTL base stocks were produced by hydroisomerizing
Fischer-Tropsch wax in a pilot plant to prepare, e.g., a base stock
with kV @ 100.degree. C. of 6 mm.sup.2/s.
[0170] EBC base stocks produced in a pilot plant with 28 and 114
mm.sup.2/s at 100.degree. C. were used for the lubricant
formulation. These samples were prepared in the following
manner:
Example A--Preparation of 28 cSt EBC Sample
[0171] 1-butene was charged at 100 ml/hour, ethylene was charged at
30 gram/hour and hydrogen gas was charged at 21.8 ml per minute
into a 600 ml autoclave containing a catalyst solution of 20 mg
zirconocene dichloride, 4.0 gram of 10 wt % methylaluminoxane in
toluene and 50 gram toluene, and cooled in an ice water bath. The
reaction mixture quickly warmed to 25.degree. C. The reaction
temperature was maintained at close to room temperature with
water/ice cooling. The feeds were discontinued after four hours.
After 12 hours of reaction at room temperature or below, the
reaction was stopped by addition of air to the reactions system.
The viscous liquid product was isolated in 73% yield by
distillation at 140.degree. C./0.1 millitorr for 2 hours to remove
any light end. The isolated ethylene-butene copolymer product had
the following properties: 100.degree. C. Kv=28.0 cS, 40.degree. C.
Kv=234.2 cS, VI=156. This polymer was used in the blend study. The
polymer contained about 33 wt % ethylene.
Example B
[0172] This polymer was prepared in a continuous mode of operation.
In this reaction, polymer grade ethylene, polymer grade 1-butene
and polymer grade iso-butane solvent were charged into a 200 gallon
reactor after purification through molecular sieve and treatment by
injecting 50 ppm tri-t-butylaluminum. The feed rates for ethylene,
1-butene and iso-butane were 12, 120 and 180 lb/hour, respectively.
A catalyst solution, containing 5.times.10.sup.-6 g-mole/liter of
dimethylsilylbis (4,5,6,7 tetrahydro-indenyl) zirconium dichloride
and methyl-aluminoxane of 1/400 Zr/Al molar ratio in toluene, was
charged into the reactor at 13.5 ml/minute. The reactor temperature
was maintained 89.4.degree. C. and 95.6.degree. C., pressure
237-261 psi and average residence time 2 hours. The crude reaction
product was withdrawn form the reactor continuously and washed with
0.4 wt % sodium hydroxide solution followed with a water wash. A
viscous liquid product was obtained by devolitalization to remove
iso-butane solvent, light stripping at 66.degree. C./5 psig
followed by deep stripping at 140.degree. C./1 millitorr. The
residual viscous liquid was then hydro-finished at 200.degree. C.,
800-1200 psi H.sub.2 pressure with 2 wt % Ni-on-Kieselguhr catalyst
for eight hours. The hydrogenated product contains 34 wt % ethylene
content and had the following properties: 100.degree. C. Kv=114.0
mm.sup.2/s, 40.degree. C. Kv=1946.5 mm.sup.2/s, VI=145 and pour
point=-24.degree. C. This polymer has Mn of 2374 and MWD of
1.88.
[0173] The Group I mineral oil bright stock to which the inventive
samples were compared has the following properties: [0174]
kinematic viscosity at 100.degree. C.=3.13 mm.sup.2/s, kinematic
viscosity at 40.degree. C.=454.5 mm.sup.2/s, VI=97, pour
point=-9.degree. C.
[0175] The Group II hydroprocessed base stock is a commercial base
stock with kV @ 40.degree. C. of 11 mm.sup.2/s.
[0176] Identical additives were used within each series of examples
1 and 2, which, in combination with the listed base stocks produced
a premium multi-purpose lubricant suitable for circulating, gear,
hydraulic, and other applications.
[0177] The thermal stability test procedure used in Examples 1 and
2 is described below: [0178] 1. Record the weight of flask and
stirrer and the weight of adapter and thermal well. [0179] 2. In a
small flask with a small stirrer, weigh 10 grams of sample oil.
[0180] 3. Assemble the flask with stirrer and oil, adapter and
thermal well--record the total weight. [0181] 4. Attach the
assembly to vacuum and nitrogen lines that can be isolated from the
sample. Connect thermocouple for temperature measurement. Stir at
low speed. [0182] 5. Evacuate, then refill the flask with nitrogen.
Repeat the evacuation and filling with nitrogen 2 more times. Leave
the flask open to nitrogen atmosphere and to a nitrogen bubbler.
[0183] 6. Wrap the flask with thermal insulating cloth. Heat the
flask to 300.degree. C. Hold at those conditions for 24 hours after
the temperature reached 300.degree. C. [0184] 7. Cool down under
nitrogen until near room temperature. Weigh complete assembly.
[0185] 8. Measure the oil viscosity at 100.degree. C. and
40.degree. C.
Example 1
[0186] Lubricant formulations with kV @ 40.degree. C. of about 220
mm.sup.2/s were obtained by blending ethylene-butene copolymers
(EBC) and a GTL base stock, or by blending a 100 mm.sup.2/s
poly-alpha-olefin (PAO) and GTL base stock for comparison against
lubricant formulations of a heavy Group I mineral oil base stock
(bright stock), or with a blend of a Group I/GTL base stock with
20% PIB thickeners. The GTL/EBC and GTL/PAO blends both have
superior oxidative stability as shown by the long RBOT time by ASTM
D2272 method. This RBOT time is much longer than that of the fluid
prepared from Group I bright stock [2126 minute and 2252 minutes
versus 750-760 minutes]. By the addition of GTL to a blend of Group
I bright stock and PIB, a conventionally used thickener, the
oxidative stability by RBOT was improved slightly [991-963 minutes
vs. 750-760 minutes]. However, compared to the GTL/EBC and GTL/PAO
products, the Group I/GTL/PIB product [the PIB-thickened fluid]
lost much more viscosity and weight during the thermal stability
test than did the EBC or PAO thickened product. These results
demonstrated that the EBC and PAO thickened GTL-based lubricants
have unexpected improvement in properties in the retention of
viscosity and weight (see Table A). TABLE-US-00002 TABLE A Gp
I/GTL/ Wt % GTL/EBC GTL/PAO Group I PIB EBC 114 mm.sup.2/s 45.8 EBC
28 mm.sup.2/s 11.4 GTL 6 mm.sup.2/s 20 20 16.6 PAO-100 mm.sup.2/s
57.2 Bright stock 76.7 40.1 PIB 20.0 Additives 23.3 23.3 23.3 23.3
KV @ 40.degree. C. 243 249 211 230 (mm.sup.2/s) D2272 (RBOT), 2126,
2193 2229, 2252 750, 760 991, 963 min Pour point, .degree. C. -31
-34 -22 -26 Weight After thermal stability test, 1 day at
300.degree. C. % loss in -4.7 -1.7 -4.2 15.0 Kv at 40.degree. C. %
weight loss 1.6 1.4 0.0 5.0
Example 2
[0187] Lubricant formulations with kV @40.degree. C. of about 220
mm.sup.2/s were prepared by blending a combination of EBC and Group
II base stock for comparison with a Group I bright stock per se and
with a mixture of Group I/Group II oil thickened with 20% PIB. The
oxidative stability of the EBC-Group II blend is superior to that
of the conventional Group I bright stock mineral oil as shown by
the RBOT data while both the oxidative and thermal stability of the
EBC-Group II blend are superior to that of the PIB thickened Group
I/Group II blend shown by both the RBOT data and its resistance to
loss of both viscosity and weight. Use of Group II hydroprocessed
base stock and PIB to displace some of the conventional mineral oil
in the all conventional Group I bright stock mineral oil
formulation improved the oxidative stability and pour point, but
the thermal stability was not as good as that of the Group II-EBC
combination nor as good as that of the Group I bright stock mineral
oil formulations itself. The resistance to viscosity and weight
loss was not as good as that secured with the GTL/EBC or GTL/PAO
blend formulations of Example I (see Table B). TABLE-US-00003 TABLE
B Group II/ Wt % EBC Group I Group II/Group I/PIB EBC 114
mm.sup.2/s 35.9 (Example B) EBC 28 mm.sup.2/s 9.0 (Example A)
Hydroprocessed base 31.8 33.1 stock (Group II) Bright stock (Group
I) 76.7 23.5 PIB 20.0 Additives 23.3 23.3 23.3 KV @ 40.degree. C.
(mm.sup.2/s) 241 211 246 D2272 (RBOT), min 1906, 2147 750, 760
1055, 1153 Pour point, .degree. C. -28 -22 -24 After thermal
stability test, 1 day at 300.degree. C. % loss in kinematic 5.2
-4.2 26.0 viscosity at 40.degree. C. % weight loss 0.0 0.0 1.6
* * * * *