U.S. patent application number 12/769585 was filed with the patent office on 2010-10-28 for two-cycle gasoline engine lubricant with a base oil having a low traction coefficient.
This patent application is currently assigned to Chevron U.S.A. Inc.. Invention is credited to Nancy J. Bertrand, Stephen J. Miller, Joseph Pudlak, John M. Rosenbaum, Joseph Timar.
Application Number | 20100270206 12/769585 |
Document ID | / |
Family ID | 40387703 |
Filed Date | 2010-10-28 |
United States Patent
Application |
20100270206 |
Kind Code |
A1 |
Timar; Joseph ; et
al. |
October 28, 2010 |
TWO-CYCLE GASOLINE ENGINE LUBRICANT WITH A BASE OIL HAVING A LOW
TRACTION COEFFICIENT
Abstract
We provide a process, comprising: a) hydroisomerization dewaxing
a substantially paraffinic wax feed and distilling a dewaxed
product, whereby a lubricating base oil is produced having a
traction coefficient less than 0.015 when measured at 15 mm.sup.2/s
and at a slide to roll ratio of 40 percent; and b) blending one or
more fractions of the lubricating base oil with: i) optionally less
than about 5 wt % of a hydrocarbon solvent, ii) another base oil,
and iii) one or more additives; whereby the lubricating oil is a
two-cycle gasoline engine lubricant. We also provide a lubricating
oil, comprising an isomerized base oil having a traction
coefficient less than 0.015 when measured at 15 mm.sup.2/s and at a
slide to roll ratio of 40 percent, and one or more additives;
wherein the lubricating oil is a two-cycle gasoline engine
lubricant.
Inventors: |
Timar; Joseph; (El Cerrito,
CA) ; Bertrand; Nancy J.; (Lafayette, CA) ;
Rosenbaum; John M.; (Richmond, CA) ; Pudlak;
Joseph; (Vallejo, CA) ; Miller; Stephen J.;
(San Francisco, CA) |
Correspondence
Address: |
CHEVRON CORPORATION
P.O. BOX 6006
SAN RAMON
CA
94583-0806
US
|
Assignee: |
Chevron U.S.A. Inc.
|
Family ID: |
40387703 |
Appl. No.: |
12/769585 |
Filed: |
April 28, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11845600 |
Aug 27, 2007 |
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12769585 |
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11845609 |
Aug 27, 2007 |
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11845600 |
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Current U.S.
Class: |
208/18 ;
208/28 |
Current CPC
Class: |
C10M 2205/163 20130101;
C10N 2030/50 20200501; C10N 2040/26 20130101; C10N 2020/015
20200501; C10M 2203/102 20130101; C10N 2030/70 20200501; C10M
2205/173 20130101; C10N 2020/071 20200501; C10N 2030/10 20130101;
C10N 2030/02 20130101; C10N 2030/45 20200501; C10N 2030/74
20200501; C10N 2020/04 20130101; C10N 2020/02 20130101; C10N
2020/065 20200501; C10M 2203/10 20130101; C10M 169/04 20130101;
C10M 2209/084 20130101; C10M 2205/0265 20130101; C10N 2030/04
20130101 |
Class at
Publication: |
208/18 ;
208/28 |
International
Class: |
C10M 169/04 20060101
C10M169/04; C10G 73/02 20060101 C10G073/02 |
Claims
1. A process to prepare a lubricating oil, comprising: a.
hydroisomerization dewaxing a substantially paraffinic wax feed and
distilling a dewaxed product, whereby a lubricating base oil is
produced from the dewaxed product having a traction coefficient
less than 0.015 when measured at 15 mm.sup.2/s and at a slide to
roll ratio of 40 percent; and b. blending one or more fractions of
the lubricating base oil with: i. optionally less than about 5 wt %
based on the total lubricating oil composition of a hydrocarbon
solvent having a maximum boiling point less than 250 degrees C, ii.
another base oil, and iii. one or more additives; whereby the
lubricating oil is a two-cycle gasoline engine lubricant.
2. The process of claim 1, wherein the substantially paraffinic wax
feed is Fischer-Tropsch derived.
3. The process of claim 1, wherein the two-cycle gasoline engine
lubricant meets the requirements of JASO M345:2003.
4. The process of claim 1, wherein the another base oil has a
viscosity index greater than an amount defined by the equation:
VI=28.times.Ln (Kinematic Viscosity at 100.degree. C., in
mm.sup.2/s)+95.
5. The process of claim 1, wherein the blending one or more
fractions of the lubricating base oil is done with less than about
2 wt % based on the total lubricating oil composition of the
hydrocarbon solvent.
6. The process of claim 1, wherein the traction coefficient is less
than 0.011.
7. The process of claim 1, wherein the lubricating base oil has a
50 wt % boiling point greater than 565.degree. C. (1050.degree.
F.).
8. The process of claim 1, wherein the two-cycle gasoline engine
lubricant has a Brookfield Viscosity at -25.degree. C. of about
7500 mPas or less.
9. The process of claim 1, wherein the two-cycle gasoline engine
lubricant has an exhaust smoke index of 85 or higher.
10. The process of claim 1, wherein the two-cycle gasoline engine
lubricant has a flash point greater than 100.degree. C.
11. A lubricating oil, comprising: a. an isomerized base oil having
a traction coefficient less than 0.015 when measured at 15
mm.sup.2/s and at a slide to roll ratio of 40 percent; and b. one
or more additives; wherein the lubricating oil is a two-cycle
gasoline engine lubricant.
12. The lubricating oil of claim 11, wherein the two-cycle gasoline
engine lubricant meets the requirements of JASO M345:2003.
13. The lubricating oil of claim 11, wherein the isomerized base
oil is made from Fischer-Tropsch wax.
14. The lubricating oil of claim 1, wherein the two-cycle gasoline
engine lubricant has a Brookfield Viscosity at -25.degree. C. of
about 7500 mPas or less.
15. The lubricating oil of claim 1, wherein the two-cycle gasoline
engine lubricant has an exhaust smoke index of 85 or higher.
16. The lubricating oil of claim 1, wherein the two-cycle gasoline
engine lubricant has a flash point greater than 100.degree. C.
17. The lubricating oil of claim 14, wherein the two-cycle gasoline
engine lubricant has: a. a passing result in the miscibility test
by ASTM D4682-87 (Reapproved 2002) at -25.degree. C.; d. an exhaust
smoke index of greater than 65; and e. a pour point less than or
equal to about -35.degree. C.
18. The lubricating oil of claim 11, wherein the one or more
additives comprises a smoke-suppression agent.
19. The lubricating oil of claim 18, wherein the smoke-suppression
agent is polyisobutylene.
20. The lubricating oil of claim 11, wherein the two-cycle gasoline
engine lubricant has a detergency index, 180-minute evaluation, of
101 or higher.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. Nos. 11/845,600, published as US20090062161, and
Ser. No. 11/845,609, published as US20090062168; and herein
incorporated in their entireties.
FIELD OF THE INVENTION
[0002] This invention is directed to a process for making an
improved two-cycle gasoline engine lubricant composition requiring
reduced amounts of hydrocarbon solvent.
BACKGROUND OF THE INVENTION
[0003] Two-cycle engines have three important advantages over
four-cycle engines: [0004] Two-cycle engines do not have valves,
which simplifies their construction and lowers their weight. [0005]
Two-cycle engines fire once every revolution, while four-cycle
engines fire once every other revolution. This gives two-cycle
engines a significant power boost. [0006] Two-cycle engines can
work in any orientation, which can be important in something like a
chainsaw. A standard four-cycle engine may have problems with oil
flow unless it is upright, and solving this problem can add
complexity to the engine.
[0007] There are at least three potential disadvantages of
two-cycle engines, including: [0008] Two-cycle engines don't last
nearly as long as four-cycle engines. The lack of a dedicated
lubrication system means that the parts of a two-cycle engine wear
a lot faster. [0009] Two-cycle gasoline engine lubricant is
expensive, and you need about 4 ounces of it per gallon of
gasoline. About a gallon of lubricant would be consumed every 1,000
miles if you used a two-cycle engine in an automobile. [0010]
Two-cycle engines produce a lot of pollution, including smoke from
the combustion of the two-cycle gasoline engine lubricant, and
leakage of the two-cycle gasoline engine lubricant out through the
exhaust port.
[0011] The majority of two-cycle gasoline engine lubricants are
formulated with low-boiling hydrocarbon solvent and SAE 40 mineral
base oils. Others have used ester base oils with no low-boiling
solvent to reduce the hazard potential and minimize smoky
emissions, however these lubricants do not have very good oxidation
stability. Others have used polyalphaolefin base oils having
improved low temperature properties. Polyalphaolefin and ester base
oils are limited in supply and very expensive. Improved two-cycle
gasoline engine lubricant compositions, comprising less expensive
base oils, and meeting the requirements set by standard setting
organizations are desired. It is also desired that these lubricant
compositions have reduced levels of hydrocarbon solvent, reduced
engine wear, and reduced pollution. It is also desired that
two-cycle gasoline engine lubricant compositions have good low
temperature performance, good gasoline miscibility, and high
oxidation stability. It is also desired that two-cycle gasoline
engine lubricant compositions have higher flash points and reduced
flammability. It is also desired that two-cycle gasoline engine
lubricant compositions can be made using polyethylene plastic, to
reduce waste plastic environmental pollution.
SUMMARY OF THE INVENTION
[0012] The present invention provides a process to prepare a
lubricating oil, comprising: [0013] a. hydroisomerization dewaxing
a substantially paraffinic wax feed to produce a lubricating base
oil; and [0014] b. blending one or more fractions of the
lubricating base oil with: [0015] i. less than about 5 wt % based
on the total lubricating oil composition of a hydrocarbon solvent
having a maximum boiling point less than 250 degrees C, and [0016]
ii. a detergent/dispersant additive package; wherein the
lubricating oil meets the requirements of JASO M345:2003.
[0017] The present invention also provides a process for making a
lubricating oil, comprising: [0018] a. blending together: [0019] i.
one or more fractions of base oil having a kinematic viscosity at
100.degree. C. between about 1.5 and about 3.5 mm.sup.2/s, and
[0020] ii. a pour point reducing blend component, to produce a pour
point reduced base oil blend; [0021] b. adding to the pour point
reduced base oil blend: [0022] i. a detergent/dispersant additive
package; [0023] ii. a smoke-suppression agent; [0024] iii.
optionally a pour point depressant; and [0025] iv. optionally less
than about 5 wt % hydrocarbon solvent having a maximum boiling
point less than 250 degrees C; [0026] whereby a two-cycle gasoline
engine lubricant is produced.
[0027] The present invention also provides a process for making a
two-cycle gasoline engine lubricant meeting the JASO M345:2003
requirements, comprising: [0028] a. preparing a pour point reducing
blend component by isomerizing a feed; [0029] b. blending the pour
point reducing blend component with [0030] i. a distillate base oil
having a kinematic viscosity at 100.degree. C. between about 1.5
and about 3.5 mm.sup.2/s to produce a pour point reduced base oil
blend; [0031] c. blending the pour point reduced base oil blend
with: [0032] i. a detergent/dispersant additive package; and [0033]
ii. less than 5 wt %, based on the total two-cycle gasoline engine
lubricant, of a hydrocarbon solvent having a maximum boiling point
less than 250 degrees C; [0034] in the proper proportions to yield
the two-cycle gasoline engine lubricant.
[0035] The present invention also provides a lubricating oil made
by a process, comprising: [0036] a. hydroisomerization dewaxing a
substantially paraffinic wax feed, whereby a lubricating base oil
is produced; and [0037] b. blending one or more fractions of the
lubricating base oil with: [0038] i. less than about 5 wt % based
on the total lubricating oil composition of a hydrocarbon solvent
having a maximum boiling point less than 250 degrees C, and [0039]
ii. a detergent/dispersant additive package; whereby the
lubricating oil meets the requirements of JASO M345:2003.
BRIEF DESCRIPTION OF THE DRAWING
[0040] FIG. 1 illustrates the plots of Kinematic Viscosity at
100.degree. C. vs. Noack Volatility, in weight percent, providing
the equations for calculation of the upper limits of wt % Noack
Volatility of:
Noack Volatility Factor (1)=160-40(Kinematic Viscosity at
100.degree. C.),
and
Noack Volatility Factor (2)=900.times.(Kinematic Viscosity at
100.degree. C.).sup.-2.8-15,
wherein the Kinematic Viscosity at 100.degree. C. is raised to the
power of -2.8 in the second equation.
DETAILED DESCRIPTION OF THE INVENTION
[0041] To operate a two-cycle gasoline engine the crankcase holds a
mixture of two-cycle gasoline engine lubricant and fuel. In a
two-cycle engine the crankcase is serving as a pressurization
chamber to force air/fuel into the cylinder, so it can't hold high
viscosity oil like what may be used in a four-cycle engine.
Instead, specialized two-cycle gasoline engine lubricant is mixed
in with the fuel to lubricate the crankshaft, connecting rod and
cylinder walls.
[0042] The recommended mix ratio of two-cycle gasoline engine
lubricant and fuel are specified by the engine manufacturer. The
fuels useful in two-cycle gasoline engines are well known to those
skilled in the art and usually contain a major portion of a
normally liquid fuel such as a hydrocarbonaceous petroleum
distillate fuel, e.g., spark ignition engine fuel as defined by
ASTM D4814-07, or motor gasoline as defined by ASTM D439-89. Such
fuels can also contain non-hydrocarbonaceous materials such as
alcohols, ethers, organo nitro compounds and the like. For example,
methanol, ethanol, diethyl ether, methylethyl ether, nitro methane
and such fuels are within the scope of this invention as are liquid
fuels derived from vegetable and mineral sources such as corn,
switch grass, alpha shale and coal. Examples of such fuel mixtures
are combinations of gasoline and ethanol, diesel fuel and ether,
gasoline and nitro methane, etc. In one embodiment the fuel is
lead-free gasoline.
[0043] Two-cycle gasoline engine lubricants are used in admixture
with fuels in amounts of about 20 to 250 parts by weight of fuel
per 1 part by weight of lubricating oil, more typically about
30-100 parts by weight of fuel per 1 part by weight of
lubricant.
[0044] Two-cycle gasoline engine lubricants must meet requirements
set by standards setting organizations, including Japanese
Automobile Standard JASO M345:2003 and International Standard ISO
13738:2000(E). The requirements of these two standards are
summarized in the table below.
TABLE-US-00001 TABLE I Performance Classification Test Parameter B
C D Method Kinematic Viscosity at 6.5 6.5 6.5 ISO 3104 100.degree.
C., mm.sup.2/s min. min. min. Flash Point, .degree. C., 70 70 70
JIS K 2265 Pensky-Martens closed min. min. min. cup method Sulfated
Ash, wt % 0.25 0.25 0.18 ISO 3987 max. max. max. Lubricity Index 95
95 95 JASO min. min. min. M340-92 Initial Torque Index 98 98 98
JASO min. min. min. M340-92 60-minute evaluation 85 95 -- JASO
Detergency Index min. min. M341-92 180-minute evaluation -- -- 125
CEC L- min. 079-T-97 Piston-Skirt Deposits 85 90 -- JASO Index min.
min. M341-92 -- -- 95 CEC L- min. 079-T-97 Exhaust Smoke Index 45
85 85 JASO min. min. min. M342-92 Exhaust-System 45 90 90 JASO
Blocking Index min. min. min. M343-92
[0045] The indexes in the table of requirements above are
determined by taking JATRE-1 oil as having a value of 100.
Classification C applies to what is called low-smoke type oil that
has superior exhaust smoke performance and exhaust system blocking
tendency. Classification D is applied to oils with better
detergency than Classification C oils when the engine is hot.
Classification B, C and D oils in the ISO standard all have a
sulfated ash content of 0.18 wt % maximum. Sulfated ash may be
measured according to ISO 3987 or ASTM D874-00.
[0046] Additionally, it is desired that these lubricants have good
low temperature fluidity when they are to be used in conditions
where low temperatures are encountered. Low temperature fluidity is
measured by determining the Brookfield Viscosity measured by ASTM
D2983-04a at defined temperatures of -10.degree. C., -25.degree.
C., and -40.degree. C. "Good low temperature fluidity" at one of
the temperatures measured is defined in this disclosure as when the
oil being tested has a Brookfield Viscosity of about 7500 mPas or
less. For example, good low temperature fluidity at -10.degree. C.
means that the oil has a Brookfield Viscosity at -10.degree. C. of
about 7500 mPas or less; good low temperature fluidity at
-25.degree. C. means that the oil has a Brookfield Viscosity at
-25.degree. C. of about 7500 mPas or less; and good low temperature
fluidity at -40.degree. C. means that the oil has a Brookfield
Viscosity at -40.degree. C. of about 7500 mPas or less.
[0047] Additionally, it is desired that these lubricants have
passing results in the miscibility test by ASTM D4682-87
(Reapproved 2002) at temperatures of -10.degree. C. and/or
-25.degree. C.
[0048] The two-cycle gasoline engine lubricant compositions are
particularly suited as injector oils or at up to a 150:1 fuel to
lubricant mix ratio with an appropriate fuel such as gasoline in
carbureted, electronic fuel injected and direct fuel injected
two-cycle engines, including: outboard motors, snowmobiles,
motorcycles, mopeds, ATVs, golf carts, lawn mowers, chain saws,
string trimmers and the like.
Base Oil:
[0049] The lubricant base oils used in the two-cycle gasoline
engine lubricant compositions are derived from substantially
paraffinic waxy feeds. The term "substantially paraffinic" means
containing a high level of n-paraffins, generally greater than 40
wt %. Some substantially paraffinic waxy feeds may have for example
greater than 50 wt %, or greater than 75 wt % n-paraffins. One
example of a substantially paraffinic waxy feed is wax produced in
a Fischer-Tropsch process. Another example is highly refined slack
wax.
[0050] Fischer-Tropsch waxes can be obtained by well-known
processes such as, for example, the commercial SASOL.RTM. Slurry
Phase Fischer-Tropsch technology, the commercial SHELL.RTM. Middle
Distillate Synthesis (SMDS) Process, or by the non-commercial
EXXON.RTM. Advanced Gas Conversion (AGC-21) process. Details of
these processes and others are described in, for example,
EP-A-776959, EP-A-668342; U.S. Pat. Nos. 4,943,672, 5,059,299,
5,733,839, and RE39073; and US Published Application No.
2005/0227866, WO-A-9934917, WO-A-9920720 and WO-A-05107935. The
Fischer-Tropsch synthesis product usually comprises hydrocarbons
having 1 to 100, or even more than 100 carbon atoms, and typically
includes paraffins, olefins and oxygenated products. Fischer
Tropsch is a viable process to generate clean alternative
hydrocarbon products, including Fischer-Tropsch waxes.
[0051] Slack wax can be obtained from conventional petroleum
derived feedstocks by either hydrocracking or by solvent refining
of the lube oil fraction. Typically, slack wax is recovered from
solvent dewaxing feedstocks prepared by one of these processes.
Hydrocracking is usually preferred because hydrocracking will also
reduce the nitrogen content to a low value. With slack wax derived
from solvent refined oils, deoiling may be used to reduce the
nitrogen content and raise the viscosity index. Hydrotreating of
the slack wax can be used to lower the nitrogen and sulfur content.
Slack waxes posses a very high viscosity index, normally in the
range of from about 140 to 200, depending on the oil content and
the starting material from which the slack wax was prepared.
Therefore, slack waxes are suitable for the preparation of base
oils used in two-cycle gasoline engine lubricants.
[0052] In one embodiment the waxy feed has less than 25 ppm total
combined nitrogen and sulfur. Nitrogen is measured by melting the
waxy feed prior to oxidative combustion and chemiluminescence
detection by ASTM D 4629-02. The test method is further described
in U.S. Pat. No. 6,503,956, incorporated herein. Sulfur is measured
by melting the waxy feed prior to ultraviolet fluorescence by ASTM
D 5453-00. The test method is further described in U.S. Pat. No.
6,503,956, incorporated herein.
[0053] Determination of normal paraffins (n-paraffins) in
wax-containing samples should use a method that can determine the
content of individual C7 to C110 n-paraffins with a limit of
detection of 0.1 wt %. The method used is described later in this
disclosure.
[0054] Waxy feeds are expected to be plentiful and relatively cost
competitive in the near future as large-scale Fischer-Tropsch
synthesis processes come into production. Fischer-Tropsch derived
base oils made from these waxy feeds, and thus the two-cycle
gasoline engine lubricants comprising them, will be less expensive
than lubricants made with other synthetic oils such as
polyalphaolefins or esters. The terms "Fischer-Tropsch derived" or
"FT derived" means that the product, fraction, or feed originates
from or is produced at some stage by a Fischer-Tropsch process. The
feedstock for a Fischer-Tropsch process may come from a wide
variety of hydrocarbonaceous resources, including biomass, natural
gas, coal, shale oil, petroleum, municipal waste, derivatives of
these, and combinations thereof. Syncrude prepared from the
Fischer-Tropsch process comprises a mixture of various solid,
liquid, and gaseous hydrocarbons. Those Fischer-Tropsch products
which boil within the range of lubricating base oil contain a high
proportion of wax which makes them ideal candidates for processing
into base oil. Accordingly, Fischer-Tropsch wax represents an
excellent feed for preparing high quality base oils.
Fischer-Tropsch wax is normally solid at room temperature and,
consequently, displays poor low temperature properties, such as
pour point and cloud point. However, following hydroisomerization
of the wax, Fischer-Tropsch derived base oils having excellent low
temperature properties may be prepared. A general description of
examples of suitable hydroisomerization dewaxing processes may be
found in U.S. Pat. Nos. 5,135,638 and 5,282,958; and US Patent
Application 20050133409, incorporated herein.
[0055] The hydroisomerization is achieved by contacting the waxy
feed with a hydroisomerization catalyst in an isomerization zone
under hydroisomerizing conditions. The hydroisomerization catalyst
preferably comprises a shape selective intermediate pore size
molecular sieve, a noble metal hydrogenation component, and a
refractory oxide support. The shape selective intermediate pore
size molecular sieve is preferably selected from the group
consisting of SAPO-11, SAPO-31, SAPO-41, SM-3, ZSM-22, ZSM-23,
ZSM-35, ZSM-48, ZSM-57, SSZ-32, offretite, ferrierite, and
combinations thereof. SAPO-11, SM-3, SSZ-32, ZSM-23, ZSM-48, and
combinations thereof are used in one embodiment. In one embodiment
the noble metal hydrogenation component is platinum, palladium, or
combinations thereof.
[0056] The hydroisomerizing conditions depend on the waxy feed
used, the hydroisomerization catalyst used, whether or not the
catalyst is sulfided, the desired yield, and the desired properties
of the base oil. Examples of hydroisomerizing conditions of one
embodiment include temperatures of 260 degrees C. to about 413
degrees C (500 to about 775 degrees F.); a total pressure of 15 to
3000 psig, or 50 to 1000 psig; and a hydrogen to feed ratio from
about 2 to 30 MSCF/bbl, about 4 to 20 MSCF/bbl (about 712.4 to
about 3562 liter H.sub.2/liter oil), about 4.5 or 5 to about 10
MSCF/bbl, or about 5 to about 8 MSCF/bbl. Generally, hydrogen will
be separated from the product and recycled to the isomerization
zone. Note that a feed rate of 10 MSCF/bbl is equivalent to 1781
liter H2/liter feed. Generally, hydrogen will be separated from the
product and recycled to the isomerization zone.
[0057] Optionally, the base oil produced by hydroisomerization
dewaxing may be hydrofinished. The hydrofinishing may occur in one
or more steps, either before or after fractionating of the base oil
into one or more fractions. The hydrofinishing is intended to
improve the oxidation stability, UV stability, and appearance of
the product by removing aromatics, olefins, color bodies, and
solvents. A general description of hydrofinishing may be found in
U.S. Pat. Nos. 3,852,207 and 4,673,487, incorporated herein. The
hydrofinishing step may be needed to reduce the weight percent
olefins in the base oil to less than 10, less than 5 or 2, less
than 1, less than 0.5, and less than 0.05 or 0.01. The
hydrofinishing step may also be needed to reduce the weight percent
aromatics to less than 0.3 or 0.1, less than 0.05, less than 0.02,
and in some embodiments even less than 0.01.
[0058] Optionally, the base oil produced by hydroisomerization
dewaxing may be treated with an adsorbent such as bauxite or clay
to remove impurities and improve the color and
biodegradability.
[0059] Because it is made from a waxy feed, the base oil has
consecutive numbers of carbon atoms. By "consecutive numbers of
carbon atoms" we mean that the hydrocarbon molecules of the base
oil differ from each other by consecutive numbers of carbon atoms,
as a consequence of the waxy feed also having sequential numbers of
carbon atoms. For example, in the Fischer-Tropsch hydrocarbon
synthesis reaction the source of carbon atoms is CO and the
hydrocarbon molecules are built up one carbon atom at a time.
Petroleum-derived waxy feeds also have sequential numbers of carbon
numbers. In contrast to an oil based on PAO, the molecules of the
base oil have a more linear structure, comprising a relatively long
backbone with short branches. The classic textbook description of a
PAO is a star-shaped molecule, and in particular tridecane, which
is illustrated as three decane molecules attached at a central
point. While a star-shaped molecule is theoretical, nevertheless
PAO molecules have fewer and longer branches that the hydrocarbon
molecules that make up the base oil used in this disclosure. In
another embodiment the base oil having consecutive numbers of
carbon atoms also has less than 10 wt % naphthenic carbon by
n-d-M.
[0060] In one embodiment the lubricating base oil is separated into
fractions, whereby one or more of the fractions will have a pour
point less than 0.degree. C., less than -9.degree. C., less than
-15.degree. C., less than -20.degree. C., less than -30.degree. C.,
or less than -35.degree. C. Pour point is measured by ASTM D
5950-02. The base oil is optionally fractionated into different
viscosity grades of base oil. In the context of this disclosure
"different viscosity grades of base oil" is defined as two or more
base oils differing in kinematic viscosity at 100 degrees C. from
each other by at least 0.5 mm.sup.2/s. Kinematic viscosity is
measured using ASTM D445-06. Fractionating is done using a vacuum
distillation unit to yield cuts with pre selected boiling ranges.
One of the fractions may be a distillation bottoms product.
[0061] In one embodiment the base oil fractions have less than 0.01
wt % aromatic carbon and greater than about 90 wt % paraffinic
carbon. The balance of the wt % carbon is naphthenic carbon. Wt %
aromatic, wt % paraffinic and wt % naphthenic carbon are determined
by n-d-M analysis according to ASTM D3238-95 (2005). In one
embodiment the wt % paraffinic carbon is between about 90 wt % and
about 97 wt % and the wt % naphthenic carbon is between about 3 wt
% and about 10 wt %.
[0062] In one embodiment, the viscosity indexes of the lubricating
base oil fractions will be high. They will often have viscosity
indexes greater than 28.times.Ln (Kinematic Viscosity at
100.degree. C.)+80. In one embodiment they will have viscosity
indexes greater than 28.times.Ln (Kinematic Viscosity at
100.degree. C.)+95. For example a 2.5 mm.sup.2/s oil will have a
viscosity index greater than 106, optionally greater than 121; and
a 12 mm.sup.2/s oil will have a viscosity index greater than 150,
optionally greater than 165.
[0063] In another embodiment the base oil has a pour point of less
than -8.degree. C.; a kinematic viscosity at 100.degree. C. of at
least 1.5 mm.sup.2/s; and a viscosity index greater than an amount
calculated by the equation: 22.times.Ln (Kinematic Viscosity at
100.degree. C.)+132. In this embodiment, for example, an oil with a
kinematic viscosity of 2.5 mm.sup.2/s at 100.degree. C. will have a
viscosity index greater than 152. Base oils with these properties
are described in US Patent Publication US20050077208. The term "Ln"
in the context of equations in this disclosure refers to the
natural logarithm with base `e`. The test method used to measure
viscosity index is ASTM D 2270-04.
[0064] The base oil fractions have a kinematic viscosity at
100.degree. C. between about 1.3 and 25 mm.sup.2/s. In one
embodiment the base oil fractions have a kinematic viscosity at
100.degree. C. between about 1.5 and about 3.5 mm.sup.2/s. In
another embodiment the base oil fractions have a kinematic
viscosity between about 1.8 and about 3.2 mm.sup.2/s.
[0065] In one embodiment, the base oil fraction provides excellent
oxidation stability, low Noack volatility, as well as desired
additive solubility and elastomer compatibility. The base oil
fractions have a weight percent olefins less than 10, less than 5,
less than 1, less than 0.5, or less than 0.05 or 0.01. The base oil
fractions have a weight percent aromatics less than 0.1, less than
0.05, or less than 0.02.
[0066] "Traction coefficient" is an indicator of intrinsic
lubricant properties, expressed as the dimensionless ratio of the
friction force F and the normal force N, where friction is the
mechanical force which resists movement or hinders movement between
sliding or rolling surfaces. Traction coefficient can be measured
with an MTM Traction Measurement System from PCS Instruments, Ltd.,
configured with a polished 19 mm diameter ball (SAE AISI 52100
steel) angled at 220 to a flat 46 mm diameter polished disk (SAE
AISI 52100 steel). The steel ball and disk are independently
measured at an average rolling speed of 3 meters per second, a
slide to roll ratio of 40 percent, and a load of 20 Newtons. The
roll ratio is defined as the difference in sliding speed between
the ball and disk divided by the mean speed of the ball and disk,
i.e. roll ratio=(Speed1-Speed2)/((Speed1+Speed2)-/2). In some
embodiments, the base oil fractions have a traction coefficient
less than 0.023, less than or equal to 0.021, or less than or equal
to 0.019, when measured at a kinematic viscosity of 15 mm.sup.2/s
and at a slide to roll ratio of 40 percent. In one embodiment they
have a traction coefficient less than an amount defined by the
equation: traction coefficient=0.009.times.Ln (Kinematic
Viscosity)-0.001, wherein the Kinematic Viscosity during the
traction coefficient measurement is between 2 and 50 mm.sup.2/s;
and wherein the traction coefficient is measured at an average
rolling speed of 3 meters per second, a slide to roll ratio of 40
percent, and a load of 20 Newtons.
[0067] In one embodiment the base oil fractions have a traction
coefficient less than 0.015 or less than 0.011, when measured at a
kinematic viscosity of 15 mm.sup.2/s and at a slide to roll ratio
of 40 percent. Examples of these base oil fractions with low
traction coefficients are taught in U.S. Pat. No. 7,045,055 and
U.S. patent application Ser. Nos. 11/400,570 and 11/399,773 both
filed Apr. 7, 2006. In one embodiment, the base oil has a traction
coefficient less than 0.015, and a 50 wt % boiling point greater
than 565.degree. C. (1050.degree. F.). In another embodiment, the
base oil has a traction coefficient less than 0.011 and a 50 wt %
boiling point by ASTM D 6352-04 greater than 582.degree. C.
(1080.degree. F.).
[0068] In some embodiments, the isomerized base oil having a low
traction coefficient also displays unique branching properties by
NMR, including a branching index less than or equal to 23.4, a
branching proximity greater than or equal to 22.0, and a Free
Carbon Index between 9 and 30. In one embodiment, the base oil has
at least 4 wt % naphthenic carbon, in another embodiment, at least
5 wt % naphthenic carbon by n-d-M analysis by ASTM D 3238-95
(Reapproved 2005). Two-cycle gasoline engine lubricants made
comprising base oil fractions having low traction coefficients
provide reduced engine wear.
[0069] In some embodiments, where the olefin and aromatics contents
are significantly low in the lubricant base oil fraction of the
lubricating oil, the Oxidator BN of the selected base oil fraction
will be greater than 25 hours, such as greater than 35 hours or
even greater than 40 hours. The Oxidator BN of the selected base
oil fraction will typically be less than 70 hours. Oxidator BN is a
convenient way to measure the oxidation stability of base oils. The
Oxidator BN test is described by Stangeland et al. in U.S. Pat. No.
3,852,207. The Oxidator BN test measures the resistance to
oxidation by means of a Dornte-type oxygen absorption apparatus.
See R. W. Dornte "Oxidation of White Oils," Industrial and
Engineering Chemistry, Vol. 28, page 26, 1936. Normally, the
conditions are one atmosphere of pure oxygen at 340.degree. F. The
results are reported in hours to absorb 1000 ml of O2 by 100 g. of
oil. In the Oxidator BN test, 0.8 ml of catalyst is used per 100
grams of oil and an additive package is included in the oil. The
catalyst is a mixture of soluble metal naphthenates in kerosene.
The mixture of soluble metal naphthenates simulates the average
metal analysis of used crankcase oil. The level of metals in the
catalyst is as follows: Copper=6,927 ppm; Iron=4,083 ppm;
Lead=80,208 ppm; Manganese=350 ppm; Tin=3565 ppm. The additive
package is 80 millimoles of zinc
bispolypropylenephenyldithio-phosphate per 100 grams of oil, or
approximately 1.1 grams of OLOA.TM. 260. The Oxidator BN test
measures the response of a lubricating base oil in a simulated
application. High values, or long times to absorb one liter of
oxygen, indicate good oxidation stability. Two-cycle gasoline
engine lubricants comprising base oil fractions having good
oxidation stability will also have improved oxidation
stability.
[0070] OLOA.TM. is an acronym for Oronite Lubricating Oil Additive,
which is a registered trademark of Chevron Oronite.
[0071] In some embodiments the one or more lubricating base oil
fractions will have excellent biodegradability. With suitable
hydro-processing and/or adsorbent treatment they are readily
biodegradable by the OECD 301B Shake Flask Test (Modified Sturm
Test). When the readily biodegradable base oil fractions are
blended with suitable biodegradable additives, such as selected
low-ash or ashless additives, the lubricants will provide rapid
biodegradation of spills in sensitive areas with minimal
non-biodegradable residue and will prevent costly environmental
clean-up.
[0072] In some embodiments the one or more lubricating base oil
fractions will have a low Noack volatility. Noack volatility is
usually tested according to ASTM D5800-05 Procedure B. In an
embodiment, the one or more lubricating base oil fractions have a
Noack volatility of less than 100 weight %. Noack volatility of
base oils generally increases as the kinematic viscosity decreases.
The lower the Noack volatility, the lower the tendency of base oil
and formulated oils to volatilize in service.
[0073] The "Noack Volatility Factor" of base oil is an empirical
number derived from the kinematic viscosity of the base oil. The
Noack volatility of the base oil derived from highly paraffinic wax
is very low, and in an embodiment, is less than an amount
calculated by the equation:
Noack Volatility Factor (1)=160-40(Kinematic Viscosity at
100.degree. C.).
[0074] Equation (1), as provided in U.S. Patent Application
Publication No. 2006/0201852 A1, provides Noack Volatility Factors
between 0 and 100 for kinematic viscosities between 1.5 and 4.0
mm.sup.2/s. FIG. 1 is a graph of the Noack Volatility Factor
according to Equation (1). In a second embodiment, the Noack
volatility of the one or more lubricant base oil fractions is less
than an amount calculated by the equation:
Noack Volatility Factor (2)=(900.times.(Kinematic Viscosity at
100.degree. C.).sup.-28)-15.
[0075] Equation (2), as provided in U.S. patent application Ser.
No. 11/613,936, provides Noack Volatility Factors between 0 and 100
for kinematic viscosities between 2.09 and 4.3 mm.sup.2/s. FIG. 1
also includes the Noack Volatility Factor according to Equation
(2). For kinematic viscosities in the range of 2.4 to 3.8
mm.sup.2/s, Equation (2) provides a lower Noack Volatility Factor
than does Equation (1). Lower Noack Volatility Factors in the range
of base oils having kinematic viscosities from 2.4 to 3.8
mm.sup.2/s are desired, especially if the base oils are to be
blended with other oils that may have higher Noack
volatilities.
[0076] Additional base oils may be incorporated in the lubricant
composition in an amount from about 1.0 wt % to about 20 wt %.
Examples of these additional base oils include esters, mixtures of
esters, and complex esters as described in U.S. Pat. No. 6,197,731;
polyalphaolefins, polyinternalolefins, polyisobutenes, alkylated
aromatics such as alkylated naphthalenes, and conventional
petroleum derived API Group II and Group III mineral oils.
Pour Point Reducing Blend Component:
[0077] The two-cycle gasoline engine lubricant may comprise a pour
point reducing blend component. As used herein, "pour point
reducing blend component" refers to an isomerized waxy product with
relatively high molecular weight and a specified degree of alkyl
branching in the molecules, such that it reduces the pour point of
lubricating base oil blends containing it. Examples of a pour point
reducing blend component are disclosed in U.S. Pat. Nos. 6,150,577
and 7,053,254, and Patent Publication No. US 20050247600 A1. A pour
point reducing blend component can be: 1) an isomerized
Fischer-Tropsch derived bottoms product; 2) a bottoms product
prepared from an isomerized highly waxy mineral oil, or 3) an
isomerized oil having a kinematic viscosity at 100.degree. C. of at
least about 8 mm.sup.2/s made from polyethylene plastic.
[0078] In one embodiment, the pour point reducing blend component
is an isomerized Fischer-Tropsch derived vacuum distillation
bottoms product having an average molecular weight between 600 and
1100 and an average degree of branching in the molecules between
6.5 and 10 alkyl branches per 100 carbon atoms. Generally, the
higher molecular weight hydrocarbons are more effective as pour
point reducing blend components than the lower molecular weight
hydrocarbons. In one embodiment, a higher cut point in a vacuum
distillation unit which results in a higher boiling bottoms
material is used to prepare the pour point reducing blend
component. The higher cut point also has the advantage of resulting
in a higher yield of the distillate base oil fractions. In one
embodiment, the pour point reducing blend component is an
isomerized Fischer-Tropsch derived vacuum distillation bottoms
product having a pour point that is at least 3.degree. C. higher
than the pour point of the distillate base oil it is blended
with.
[0079] In one embodiment, the 10 percent point of the boiling range
of the pour point reducing blend component that is a vacuum
distillation bottoms product is between about 850.degree.
F.-1050.degree. F. (454-565.degree. C.). In another embodiment, the
pour point reducing blend component is derived from either
Fischer-Tropsch or petroleum products, having a boiling range above
950.degree. F. (510.degree. C.), and contains at least 50 percent
by weight of paraffins. In yet another embodiment the pour point
reducing blend component has a boiling range above 1050.degree. F.
(565.degree. C.).
[0080] In another embodiment, the pour point reducing blend
component is an isomerized petroleum derived base oil containing
material having a boiling range above about 1050.degree. F. In one
embodiment, the isomerized bottoms material is solvent dewaxed
prior to being used as a pour point reducing blend component. The
waxy products further separated during solvent dewaxing from the
pour point reducing blend component were found to display excellent
improved pour point depressing properties compared to the oily
product recovered after the solvent dewaxing.
[0081] In another embodiment, the pour point reducing blend
component is an isomerized oil having a kinematic viscosity at
100.degree. C. of at least about 8 mm2/s made from polyethylene
plastic. In one embodiment the pour point reducing blend component
is made from waste plastic. In another embodiment the pour point
reducing blend component is made from steps comprising pyrolysis of
polyethylene plastic, separating out a heavy fraction,
hydrotreating the heavy fraction, catalytic isomerizing the
hydrotreated heavy fraction, and collecting the pour point reducing
blend component having a kinematic viscosity at 100.degree. C. of
at least about 8 mm2/s. In a third embodiment, the pour point
reducing blend component derived from polyethylene plastic and has
a boiling range above 1050.degree. F. (565.degree. C.), or even has
a boiling range above 1200.degree. F. (649.degree. C.).
[0082] In one embodiment, the pour point reducing blend component
has an average degree of branching in the molecules within the
range of from 6.5 to 10 alkyl branches per 100 carbon atoms. In
another embodiment, the pour point reducing blend component has an
average molecular weight between 600-1100. In a third embodiment it
has an average molecular weight between 700-1000. In one
embodiment, the pour point reducing blend component has a kinematic
viscosity at 100.degree. C. of 8-30 mm.sup.2/s, with the 10% point
of the boiling range falling between about 850-1050.degree. F. In
yet another embodiment, the pour point reducing blend component has
a kinematic viscosity at 100.degree. C. of 15-20 mm.sup.2/s and a
pour point of -8 to -12.degree. C.
[0083] In one embodiment, the pour point reducing blend component
is an isomerized oil having a kinematic viscosity at 100.degree. C.
of at least about 8 mm.sup.2/s made from polyethylene plastic. In
one embodiment the pour point reducing blend component is made from
waste plastic. In another embodiment the pour point reducing blend
component is made from steps comprising pyrolysis of polyethylene
plastic, separating out a heavy fraction, hydrotreating the heavy
fraction, catalytic isomerizing the hydrotreated heavy fraction,
and collecting the pour point reducing blend component having a
kinematic viscosity at 100.degree. C. of at least about 8
mm.sup.2/s. In a third embodiment, the pour point reducing blend
component derived from polyethylene plastic has a boiling range
above 1050.degree. F. (565.degree. C.), or even a boiling range
above 1200.degree. F. (649.degree. C.).
Additives & Additive Packages:
[0084] Various detergent/dispersant additive packages may be
combined with base oil in formulating two-cycle oil gasoline engine
lubricants. Ashless, low-ash, or ash-containing additives may be
used for this purpose.
[0085] Suitable ashless additives include polyamide,
alkenylsuccinimides, boric acid-modified alkenylsuccinimides,
phenolic amines and succinate derivatives or combinations of any
two or more of such additives.
[0086] Examples of a low ash additive package comprise (i)
polyisobutenyl (Mn 400-2500) succinimide or another oil soluble,
acylated, nitrogen containing lubricating oil dispersant present in
the amount of 0.2-5 wt. % in the lubricating oil and (ii) a metal
phenate, sulfonate or salicylate oil soluble detergent additive. In
one embodiment, the oil soluble detergent additive is a neutral
metal detergent or overbased metal detergent of Total Base Number
200 or less, present in the amount of 0.1-2 wt % in the lubricating
oil. In this embodiment the metal is calcium, barium or magnesium.
Neutral calcium salicylates are one example, and may be present in
amounts of about 0.5 to 1.5 wt % in the lubricating oil.
[0087] Polyamide detergent/dispersant additives, such as the
commonly used tetraethylenepentamine isostearate, may be prepared
by the reaction of fatty acid and polyalkylene polyamines, as
described in U.S. Pat. No. 3,169,980, the entire disclosure of
which is incorporated by reference in this specification, as if set
forth herein in full. These polyamides may contain measurable
amounts of cyclic imidazolines formed by internal condensation of
the linear polyamides upon continued heating at elevated
temperature. Another useful class of polyamide additives is
prepared from polyalkylene polyamines and C19-C25 Koch acids,
according to the procedure of R. Hartle et al., JAOCS, 57 (5):
156-59 (1980).
[0088] Alkenylsuccinimides are formed by a step-wise procedure in
which an olefin, such as polybutene (MV 1200) is reacted with
maleic anhydride to yield a polybutenyl succinic anhydride adduct,
which is then reacted with an amine, e.g., an alkylamine or a
poly-amine, to form the desired product.
[0089] Phenolic amines are prepared by the well-known Mannich
reaction (C. Mannich and W. Krosche, Arch. Pharm., 250: 674
(1912)), involving a polyalkylene-substituted phenol, formaldehyde
and a polyalkylene polyamine.
[0090] Succinate derivatives are prepared by the reaction of an
olefin (e.g., polybutene (eg., polybutene) and maleic anhydride to
yield a polybutenyl succinic anhydride adduct, which undergoes
further reaction with a polyol, e.g., pentaerythritol, to give the
desired product.
[0091] Suitable ash-containing detergent/dispersant additives
include alkaline earth metal (e.g., magnesium, calcium, barium),
sulfonates, phosphonates or phenates or combinations of any two or
more of such additives.
[0092] The foregoing detergent/dispersant additives may be
incorporated in the lubricant compositions described herein in an
amount from about 1 to about 25 wt %, and more preferably from
about 3 to about 20 wt % based on the total weight of the
composition.
[0093] Commercially available two-cycle lubricant
detergent/dispersant additive packages may be used in combination
with the base oil to produce the two-cycle gasoline engine
lubricant, for example, LUBRIZOL 400, LUBRIZOL 6827, LUBRIZOL 6830,
LUBRIZOL 600, LUBRIZOL 606, ORONITE OLOA.RTM. 9333, ORONITE
OLOA.RTM. 340A, ORONITE OLOA.RTM. 6721 and ORONITE OLOA.RTM.
9357.
[0094] Various other additives may be incorporated in the two-cycle
gasoline engine lubricant, as desired. These include
smoke-suppression agents, such as polybutene or polyisobutylene
(PIB), extreme pressure additives, such as dialkyldithiophosphoric
acid salts or esters, anti-foaming agents, such as silicone oil,
pour point depressants, rust or corrosion prevention agents, such
as triazole derivatives, propyl gallate or alkali metal phenolates
or sulfonates, oxidation inhibitors, such as substituted
diarylamines, phenothiazines, hindered phenols, or the like.
Certain of these additives may be multifunctional, such as
polymethacrylate, which may serve as an anti-foaming agent, as well
as a pour point depressant. Pour point depressants, when used, are
used in an amount between 0.005 to 0.1 wt % based on the total
lubricating oil. Examples of pour point depressants are
polymethacrylates (PMA); polyacrylates; polyacrylamides;
condensation products of haloparaffin waxes and aromatic compounds;
vinyl carboxylate polymers; terpolymers of dialkylfumarates, vinyl
esters of fatty acids, and alkyl vinyl ethers; and mixtures
thereof.
[0095] In one embodiment, the smoke-suppression agent is an
olefinically unsaturated polymer selected from the group consisting
of polybutene, polyisobutylene or a mixture of polybutene and
polyisobutylene, which has a number average molecular weight of 400
to 2200 and a terminal vinylidene content of at least 60 mol %,
based on the total number of double bonds in the polymer. These
types of smoke-suppression agents are taught in EP1743932A2. A
commercial example of these smoke-suppression agents is BASF
Corporation's GLISSOPAL.RTM. 1000.
[0096] Volatile, combustible high flash hydrocarbon solvent such as
kerosene, Exxsol D80, or Stoddard solvent can also be used as
additives. Exxsol D80 is a dearomatized aliphatic high flash
solvent with an initial boiling point of at least 200.degree. C., a
Kauri-Butanol Value of about 28 (between 20 and 40), and an aniline
point of 73.9 to 79.4.degree. C. Volatile, combustible high flash
hydrocarbon solvents may be added to the two-cycle engine lubricant
in an amount less than 5 wt % of the total lubricating oil in order
to bring the smoke index to a value of at least 75 in the JASO M
342-92 test and/or to improve the compatibility and/or solubility
of other additives and to improve the low temperature
characteristics such as viscosity and gasoline miscibility. In one
embodiment, the two-cycle gasoline engine lubricant comprises low
levels of solvent, such as less than about 5 wt %, less than about
2 wt %, or even essentially none of the total lubricating oil is a
hydrocarbon solvent having a maximum boiling point less than 250
degrees C. Lower levels of solvent in the two-cycle gasoline engine
lubricant provides for reduced pollution by evaporation of volatile
organic contents, improved compatibility with elastomers used in
packaging and transport, and reduced flammability hazards for
enhanced transportation and storage safety.
[0097] Most of the above-described additives may be incorporated in
the lubricant composition in an amount from about 0.005% to about
15%, or from about 0.005% to about 6%, based on the total weight of
the lubricant composition. In the case of polybutene or
polyisobutylene, the amount may vary from 1% to 50%. The amount of
each additive or additive package selected within the specified
range should be such as not to adversely effect the desirable
performance properties of the lubricant. The effects produced by
such additives can be readily determined by routine testing.
[0098] Alternatively, the lubricating oil is one consisting of, or
consisting essentially of: [0099] a. between 20 and 70 wt % based
on the total lubricating oil of one or more base oil fractions
having: [0100] i. consecutive numbers of carbon atoms; [0101] ii. a
kinematic viscosity at 100.degree. C. between about 1.5 and about
3.5 mm.sup.2/s; [0102] iii. between about 90 wt % and about 97 wt %
paraffinic carbon; [0103] iv. between about 3 wt % and about 10 wt
% naphthenic carbon; [0104] v. less than 0.01 wt % aromatic carbon;
[0105] b. between 0.5 and 25 wt % based on the total lubricating
oil of a pour point reducing blend component; [0106] c. less than
about 5 wt % based on the total lubricating oil of a hydrocarbon
solvent having a maximum boiling point less than 250 degrees C;
[0107] d. from about 1 wt % to about 25 wt % based on the total
lubricating oil of a detergent/dispersant additive package; [0108]
e. from about 1 wt % to about 50 wt % based on the total
lubricating oil of a smoke-suppression agent; and [0109] f. less
than 0.1 wt % based on the total lubricating oil of a pour point
depressant; wherein the lubricating oil has a blend kinematic
viscosity at 100.degree. C. of 6.5 mm.sup.2/s or greater, good low
temperature fluidity at -25.degree. C., and an exhaust smoke index
of greater than 65.
[0110] The two-cycle gasoline engine lubricants have high flash
points due to the low level of solvent they contain. Their flash
points are in some embodiments greater than 120.degree. C., or
greater than 150.degree. C.
Specific Analytical Test Methods:
Wt % Normal Paraffins in Wax-Containing Samples:
[0111] Quantitative analysis of normal paraffins in wax-containing
samples is determined by gas chromatography (GC). The GC (Agilent
6890 or 5890 with capillary split/splitless inlet and flame
ionization detector) is equipped with a flame ionization detector,
which is highly sensitive to hydrocarbons. The method utilizes a
methyl silicone capillary column, routinely used to separate
hydrocarbon mixtures by boiling point. The column is fused silica,
100% methyl silicone, 30 meters length, 0.25 mm ID, 0.1 micron film
thickness supplied by Agilent. Helium is the carrier gas (2 ml/min)
and hydrogen and air are used as the fuel to the flame.
[0112] The waxy feed is melted to obtain a 0.1 g homogeneous
sample. The sample is immediately dissolved in carbon disulfide to
give a 2 wt % solution. If necessary, the solution is heated until
visually clear and free of solids, and then injected into the GC.
The methyl silicone column is heated using the following
temperature program: [0113] Initial temp: 150.degree. C. (If C7 to
C15 hydrocarbons are present, the initial temperature is 50.degree.
C.) [0114] Ramp: 6.degree. C. per minute [0115] Final Temp:
400.degree. C. [0116] Final hold: 5 minutes or until peaks no
longer elute
[0117] The column then effectively separates, in the order of
rising carbon number, the normal paraffins from the non-normal
paraffins. A known reference standard is analyzed in the same
manner to establish elution times of the specific normal-paraffin
peaks. The standard is ASTM D2887 n-paraffin standard, purchased
from a vendor (Agilent or Supelco), spiked with 5 wt % Polywax 500
polyethylene (purchased from Petrolite Corporation in Oklahoma).
The standard is melted prior to injection. Historical data
collected from the analysis of the reference standard also
guarantees the resolving efficiency of the capillary column.
[0118] If present in the sample, normal paraffin peaks are well
separated and easily identifiable from other hydrocarbon types
present in the sample. Those peaks eluting outside the retention
time of the normal paraffins are called non-normal paraffins. The
total sample is integrated using baseline hold from start to end of
run. N-paraffins are skimmed from the total area and are integrated
from valley to valley. All peaks detected are normalized to 100%.
EZChrom is used for the peak identification and calculation of
results.
Wt % Olefins:
[0119] The Wt % Olefins in the base oils is determined by
proton-NMR by the following steps, A-D: [0120] A. Prepare a
solution of 5-10% of the test hydrocarbon in deuterochloroform.
[0121] B. Acquire a normal proton spectrum of at least 12 ppm
spectral width and accurately reference the chemical shift (ppm)
axis. The instrument must have sufficient gain range to acquire a
signal without overloading the receiver/ADC. When a 30 degree pulse
is applied, the instrument must have a minimum signal digitization
dynamic range of 65,000. Preferably the dynamic range will be
260,000 or more. [0122] C. Measure the integral intensities
between: [0123] 6.0-4.5 ppm (olefin) [0124] 2.2-1.9 ppm (allylic)
[0125] 1.9-0.5 ppm (saturate) [0126] D. Using the molecular weight
of the test substance determined by ASTM D 2503, calculate: [0127]
1. The average molecular formula of the saturated hydrocarbons
[0128] 2. The average molecular formula of the olefins [0129] 3.
The total integral intensity (=sum of all integral intensities)
[0130] 4. The integral intensity per sample hydrogen (=total
integral/number of hydrogens in formula) [0131] 5. The number of
olefin hydrogens (=Olefin integral/integral per hydrogen) [0132] 6.
The number of double bonds (.dbd.Olefin hydrogen times hydrogens in
olefin formula/2) [0133] 7. The wt % olefins by proton NMR=100
times the number of double bonds times the number of hydrogens in a
typical olefin molecule divided by the number of hydrogens in a
typical test substance molecule.
[0134] The wt % olefins by proton NMR calculation procedure, D,
works best when the % olefins result is low, less than about 15
weight percent. The olefins must be "conventional" olefins; i.e. a
distributed mixture of those olefin types having hydrogens attached
to the double bond carbons such as: alpha, vinylidene, cis, trans,
and trisubstituted. These olefin types will have a detectable
allylic to olefin integral ratio between 1 and about 2.5. When this
ratio exceeds about 3, it indicates a higher percentage of tri or
tetra substituted olefins are present and that different
assumptions must be made to calculate the number of double bonds in
the sample.
Aromatics Measurement by HPLC-UV:
[0135] The method used to measure low levels of molecules with at
least one aromatic function in the lubricant base oils uses a
Hewlett Packard 1050 Series Quaternary Gradient High Performance
Liquid Chromatography (HPLC) system coupled with a HP 1050
Diode-Array UV-Vis detector interfaced to an HP Chem-station.
Identification of the individual aromatic classes in the highly
saturated Base oils was made on the basis of their UV spectral
pattern and their elution time. The amino column used for this
analysis differentiates aromatic molecules largely on the basis of
their ring-number (or more correctly, double-bond number). Thus,
the single ring aromatic containing molecules elute first, followed
by the polycyclic aromatics in order of increasing double bond
number per molecule. For aromatics with similar double bond
character, those with only alkyl substitution on the ring elute
sooner than those with naphthenic substitution.
[0136] Unequivocal identification of the various base oil aromatic
hydrocarbons from their UV absorbance spectra was accomplished
recognizing that their peak electronic transitions were all
red-shifted relative to the pure model compound analogs to a degree
dependent on the amount of alkyl and naphthenic substitution on the
ring system. These bathochromic shifts are well known to be caused
by alkyl-group delocalization of the .pi.-electrons in the aromatic
ring. Since few unsubstituted aromatic compounds boil in the
lubricant range, some degree of red-shift was expected and observed
for all of the principle aromatic groups identified.
[0137] Quantitation of the eluting aromatic compounds was made by
integrating chromatograms made from wavelengths optimized for each
general class of compounds over the appropriate retention time
window for that aromatic. Retention time window limits for each
aromatic class were determined by manually evaluating the
individual absorbance spectra of eluting compounds at different
times and assigning them to the appropriate aromatic class based on
their qualitative similarity to model compound absorption spectra.
With few exceptions, only five classes of aromatic compounds were
observed in highly saturated API Group II and III lubricant base
oils.
HPLC-UV Calibration:
[0138] HPLC-UV is used for identifying these classes of aromatic
compounds even at very low levels. Multi-ring aromatics typically
absorb 10 to 200 times more strongly than single-ring aromatics.
Alkyl-substitution also affected absorption by about 20%.
Therefore, it is important to use HPLC to separate and identify the
various species of aromatics and know how efficiently they
absorb.
[0139] Five classes of aromatic compounds were identified. With the
exception of a small overlap between the most highly retained
alkyl-1-ring aromatic naphthenes and the least highly retained
alkyl naphthalenes, all of the aromatic compound classes were
baseline resolved. Integration limits for the co-eluting 1-ring and
2-ring aromatics at 272 nm were made by the perpendicular drop
method. Wavelength dependent response factors for each general
aromatic class were first determined by constructing Beer's Law
plots from pure model compound mixtures based on the nearest
spectral peak absorbances to the substituted aromatic analogs.
[0140] For example, alkyl-cyclohexylbenzene molecules in base oils
exhibit a distinct peak absorbance at 272 nm that corresponds to
the same (forbidden) transition that unsubstituted tetralin model
compounds do at 268 nm. The concentration of alkyl-1-ring aromatic
naphthenes in base oil samples was calculated by assuming that its
molar absorptivity response factor at 272 nm was approximately
equal to tetralin's molar absorptivity at 268 nm, calculated from
Beer's law plots. Weight percent concentrations of aromatics were
calculated by assuming that the average molecular weight for each
aromatic class was approximately equal to the average molecular
weight for the whole base oil sample.
[0141] This calibration method was further improved by isolating
the 1-ring aromatics directly from the lubricant base oils via
exhaustive HPLC chromatography. Calibrating directly with these
aromatics eliminated the assumptions and uncertainties associated
with the model compounds. As expected, the isolated aromatic sample
had a lower response factor than the model compound because it was
more highly substituted.
[0142] More specifically, to accurately calibrate the HPLC-UV
method, the substituted benzene aromatics were separated from the
bulk of the lubricant base oil using a Waters semi-preparative HPLC
unit. 10 grams of sample was diluted 1:1 in n-hexane and injected
onto an amino-bonded silica column, a 5 cm.times.22.4 mm ID guard,
followed by two 25 cm.times.22.4 mm ID columns of 8-12 micron
amino-bonded silica particles, manufactured by Rainin Instruments,
Emeryville, Calif., with n-hexane as the mobile phase at a flow
rate of 18 mls/min. Column eluent was fractionated based on the
detector response from a dual wavelength UV detector set at 265 nm
and 295 nm. Saturate fractions were collected until the 265 nm
absorbance showed a change of 0.01 absorbance units, which signaled
the onset of single ring aromatic elution. A single ring aromatic
fraction was collected until the absorbance ratio between 265 nm
and 295 nm decreased to 2.0, indicating the onset of two ring
aromatic elution. Purification and separation of the single ring
aromatic fraction was made by re-chromatographing the monoaromatic
fraction away from the "tailing" saturates fraction which resulted
from overloading the HPLC column.
[0143] This purified aromatic "standard" showed that alkyl
substitution decreased the molar absorptivity response factor by
about 20% relative to unsubstituted tetralin.
Confirmation of Aromatics by NMR:
[0144] The weight percent of all molecules with at least one
aromatic function in the purified mono-aromatic standard was
confirmed via long-duration carbon 13 NMR analysis. NMR was easier
to calibrate than HPLC UV because it simply measured aromatic
carbon so the response did not depend on the class of aromatics
being analyzed. The NMR results were translated from % aromatic
carbon to % aromatic molecules (to be consistent with HPLC-UV and D
2007) by knowing that 95-99% of the aromatics in highly saturated
lubricant base oils were single-ring aromatics.
[0145] High power, long duration, and good baseline analysis were
needed to accurately measure aromatics down to 0.2% aromatic
molecules.
[0146] More specifically, to accurately measure low levels of all
molecules with at least one aromatic function by NMR, the standard
D 5292-99 method was modified to give a minimum carbon sensitivity
of 500:1 (by ASTM standard practice E 386). A15-hour duration run
on a 400-500 MHz NMR with a 10-12 mm Nalorac probe was used. Acorn
PC integration software was used to define the shape of the
baseline and consistently integrate. The carrier frequency was
changed once during the run to avoid artifacts from imaging the
aliphatic peak into the aromatic region. By taking spectra on
either side of the carrier spectra, the resolution was improved
significantly.
EXAMPLES
Example 1
[0147] A wax sample composed of several different batches of
hydrotreated Fischer-Tropsch wax, all made using a Co-based
Fischer-Tropsch catalyst, was prepared. The different batches of
wax composing the wax sample were analyzed and all found to have
the properties as shown in Table II
TABLE-US-00002 TABLE II Fischer-Tropsch Wax Fischer-Tropsch
Catalyst Co-Based Sulfur, ppm <10 Nitrogen, ppm <10 Oxygen,
wt % <0.50 Wt % N-Paraffins by GC >85 D 6352 SIMDIST TBP (WT
%), .degree. F. T10 550-700 T90 1000-1080 T90-T10, .degree. C.
>154
[0148] The Co-based Fischer-Tropsch wax was hydroisomerized over a
Pt/SAPO-11 catalyst with an alumina binder. Operating conditions
included temperatures between 635.degree. F. and 675.degree. F.
(335.degree. C. and 358.degree. C.), LHSV of 1.0 hr.sup.-1, reactor
pressure of about 500 psig, and once-through hydrogen rates of
between 5 and 6 MSCF/bbl. The reactor effluent passed directly to a
second reactor containing a Pd on silica-alumina hydrofinishing
catalyst also operated at 500 psig. Conditions in the second
reactor included a temperature of about 350.degree. F. (177.degree.
C.) and an LHSV of 2.0 hr.sup.-1.
[0149] The products boiling above 650.degree. F. were fractionated
by vacuum distillation to produce distillate fractions of different
viscosity grades. Three Fischer-Tropsch derived lubricant base oils
were obtained. Two were distillate side-cut fractions (XLFTBO and
XXLFTBO) and one was a distillate bottoms fraction (HFTBO). Test
data on the three Fischer-Tropsch derived lubricant base oils are
shown in Table 111, below.
TABLE-US-00003 TABLE III Sample Properties HFTBO XLFTBO XXLFTBO
Viscosity at 100.degree. C., mm.sup.2/s 16.01 2.926 2.409 Viscosity
Index 161 124 125 Pour Point, .degree. C. -10 -37 -42 D 6352
SIMDIST TBP (WT %), .degree. F. 5 963 683 625 10/30 988/1040
692/717 640/673 50 1074 737 696 70/90 1113/1181 755/777 716/738 95
1213 785 746 Wt % Aromatics 0.0306 0.0131 0.0185 Wt % Olefins
<0.1 <0.1 <0.1 n-d-M Wt % Paraffinic Carbon 92.98 95.42
96.13 Wt % Naphthenic Carbon 7.02 4.58 3.87 Wt % Aromatic Carbon
0.00 0.00 0.00 Oxidator BN, hours 45.32 40.16 47.69 X in the
equation: VI = 28 .times. 83.4 93.9 100 Ln(VIS100) + X Noack
volatility, wt % 0.95 32.37 54.1 NVF (1) = 160 - (40 .times. KV100)
42.96 63.64 NVF (2) = (900 .times. 29.5 61.75 (KV100) -.sup.2.8) -
15 Alkyl Branches per 100 Carbons 7.58 Not tested 10.2 Traction
Coefficient at 15 mm.sup.2/s <0.015 Not tested 0.032 and at a
slide to roll ratio of 40%
[0150] HFTBO is an example of a pour point reducing blend component
with a low traction coefficient. XLFTBO is an example of a fraction
of a lubricating base oil having a Noack volatility less than a
Noack Volatility Factor by Equation (1). XXLFTBO is an example of a
fraction of a lubricating base oil having a Noack volatility less
than a Noack Volatility Factor less than both a Noack Volatility
Factor by Equation (1) and a Noack Volatility Factor by Equation
(2).
Example 2
[0151] Chevron MOTEX 2T-X is a two-cycle outboard engine oil
formulated with high quality mineral base oil, polyisobutylene, a
high performance low ash detergent/dispersant additive package, and
a high flash solvent. Three different blends of two-cycle gasoline
engine lubricant using the same high performance low ash
detergent/dispersant additive package and polyisobutylene synthetic
base oil used in Chevron Motex 2T-X were prepared (BlendB, BlendC,
and BlendF) using the Fischer-Tropsch derived base oils described
earlier. A comparison blend (COMP BlendA) using conventional
mineral base oil and high flash solvent was also prepared. The
formulations of these blends are summarized in Table IV.
TABLE-US-00004 TABLE IV COMP Component, Wt % Blend A Blend B Blend
C Blend F ExxonMobil AP/E 18.50 0 0 0 Core 600N ExxonMobil AP/E
29.00 0 0 0 Core 150N Exxsol D80 20.00 0 0 0 HFTBO 0 8.40 16.90
22.50 XLFTBO 0 0 0 XXL FTBO 0 59.10 50.60 44.70 Two-cycle lubricant
5.50 5.50 5.50 5.50 detergent/dispersant additive package PIB 27.00
27.00 27.00 27.00 Pour Point 0 0 0 0.3 Depressant
[0152] The performance properties of three of these two-cycle
gasoline engine lubricant blends are shown in Table V.
TABLE-US-00005 TABLE V COMP Properties Blend A Blend B Blend C
Blend F Fluidity, mPa s -10.degree. C. 959 539 5230 Not tested
-25.degree. C. >7500 2579 Not tested 3489 Miscibility
-10.degree. C. Pass Pass Not Tested Not Tested -25.degree. C. Fail
Pass Pass Pass Kin Vis @100.degree. C., 8.058 7.137 9.13 8.082
mm.sup.2/s Viscosity Index 136 160 156 153 Pour Point, .degree. C.
-18 -40 -35 -49 Flash Point, .degree. C. 100 Not Tested Not Tested
194 Aniline Point, .degree. C. 110 Not Tested Not Tested 124
Sulfated Ash, wt % <0.15 <0.15 <0.15 <0.15 Detergency,
180- 152 148 101 Not Tested minute evaluation Piston Skirt Deposit
112 110 95 Not Tested Index Lubricity by JASCO 95 86 103 104
M340-92 Exhaust Smoke 99 88 76 70 Index
[0153] Flash Points were measured by the Cleveland Open Cup Tester,
using ASTM D92-05a. Aniline Points were measured by ASTM D611-04.
BlendB, BlendC, and BlendF had essentially no hydrocarbon solvent
having a maximum boiling point less than 250 degrees C, yet they
all had low exhaust smoke index values, lower pour points, and
improved miscibility compared to COMP BlendA made with conventional
mineral oil base oil and high flash solvent. BlendF, comprising the
highest level of HFTBO, gave an especially high lubricity index,
yet still had excellent miscibility and a good exhaust smoke
index.
Example 3
[0154] A blend of two-cycle gasoline engine lubricant using a
detergent/dispersant additive package designed to meet the
specifications for Thailand Domestic (TIS 1040-2541 [1998]) was
prepared using the Fischer-Tropsch derived base oils described
earlier. A comparison blend using conventional petroleum-derived
base oil and high flash solvent was also prepared. The formulations
of these blends are summarized in Table VI
TABLE-US-00006 TABLE VI COMP Component, Wt % Blend D Blend E TPI
600N 30.95 0 Exxsol D80 25.50 0 HFTBO 0 1.58 XLFTBO 0 0 XXLFTBO 0
54.87 Two-cycle lubricant 5.50 5.50 detergent/dispersant additive
package PIB 38.00 38.00 PMA Pour Point Depressant 0.05 0.05
[0155] The performance properties of these two-cycle gasoline
engine lubricant blends are shown in Table VII.
TABLE-US-00007 TABLE VII COMP Properties Blend D Blend E Fluidity,
mPa s -10.degree. C. 1460 1160 -25.degree. C. >7500 4799
Miscibility -10.degree. C. Pass Pass -25.degree. C. Fail Pass Kin
Vis @100.degree. C., 10.51 9.724 mm.sup.2/s Viscosity Index 133 148
Pour Point, .degree. C. -32 -50 Flash Point, .degree. C. 92 182
Aniline Point, .degree. C. 116.4 122 Sulfated Ash, wt % <0.18
<0.18 Detergency, 180- 131 151 minute evaluation Piston Skirt
Deposit 110 112 Index Exhaust Smoke Index 137 84
[0156] BlendE also comprised the pour point reducing blend
component having a low traction coefficient, HFTBO. Note that this
blend had had an especially low pour point and good low temperature
fluidity at -25.degree. C. BlendE had better low temperature
fluidity, lower pour point, better gasoline miscibility, better
detergency, and a better piston skirt deposit index than COMP
BlendD made with conventional mineral oil base oil and greater than
5 wt % hydrocarbon solvent having a maximum boiling point less than
250 degrees C. BlendE, with the addition of less than 5 wt %
hydrocarbon solvent having a maximum boiling point less than 250
degrees C, would easily pass the requirements of both JASO
M345:2003 and ISO 13738:2000(E), classifications C and D.
[0157] For the purposes of this specification and appended claims,
unless otherwise indicated, all numbers expressing quantities,
percentages or proportions, and other numerical values used in the
specification and claims, are to be understood as being modified in
all instances by the term "about." Furthermore, all ranges
disclosed herein are inclusive of the endpoints and are
independently combinable.
[0158] All of the publications, patents and patent applications
cited in this application are herein incorporated by reference in
their entirety to the same extent as if the disclosure of each
individual publication, patent application or patent was
specifically and individually indicated to be incorporated by
reference in its entirety.
[0159] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to make and use the invention. Many
modifications of the exemplary embodiments of the invention
disclosed above will readily occur to those skilled in the art.
Accordingly, the invention is to be construed as including all
structure and methods that fall within the scope of the appended
claims.
* * * * *