U.S. patent application number 10/179601 was filed with the patent office on 2003-02-20 for process for modifying unsaturated triacylglycerol oils; resulting products and uses thereof.
This patent application is currently assigned to Cargill, Incorporated. Invention is credited to Kodali, Dharma R..
Application Number | 20030036486 10/179601 |
Document ID | / |
Family ID | 25284992 |
Filed Date | 2003-02-20 |
United States Patent
Application |
20030036486 |
Kind Code |
A1 |
Kodali, Dharma R. |
February 20, 2003 |
Process for modifying unsaturated triacylglycerol oils; resulting
products and uses thereof
Abstract
A process for modifying an unsaturated triacylglycerol oil, such
as an vegetable oil stock, to enhance its fluidity and/or oxidative
stability is provided. Lubricants containing a modified an
unsaturated triacylglycerol oil and methods for their production
and use are also provided.
Inventors: |
Kodali, Dharma R.;
(Plymouth, MN) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
Cargill, Incorporated
Minneapolis
MN
|
Family ID: |
25284992 |
Appl. No.: |
10/179601 |
Filed: |
June 25, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10179601 |
Jun 25, 2002 |
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08841484 |
Apr 22, 1997 |
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6420322 |
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Current U.S.
Class: |
508/452 |
Current CPC
Class: |
C07C 67/347 20130101;
C10M 105/38 20130101; C07C 67/347 20130101; C07C 69/608
20130101 |
Class at
Publication: |
508/452 |
International
Class: |
C10M 101/00 |
Claims
What is claimed is:
1. A process for modifying an unsaturated triacylglycerol oil
comprising: reacting the unsaturated triacylglycerol oil with an
olefinic hydrocarbon to form a cycloaddition product comprising
triacylglycerols which have at least one unsaturated fatty acyl
chain modified to include a cycloaddition adduct; and at least
partially hydrogenating the cycloaddition product to form a
hydrogenated cycloaddition product.
2. The process of claim 1 wherein the at least partially
hydrogenating step comprises hydrogenating the cycloaddition
product to form a hydrogenated cycloaddition product having an
Iodine Value reduced by at least about 10% with respect to that of
the cycloaddition product.
3. The process of claim 1 wherein the at least partially
hydrogenating step comprises hydrogenating the cycloaddition
product to form a hydrogenated cycloaddition product having an
active methylene content reduced by at least about 0.5 with respect
to that of the cycloaddition product.
4. The process of claim 1 wherein the reacting step comprises
reacting the unsaturated triacylglycerol oil with an olefinic
hydrocarbon including a diene.
5. The process of claim 4 wherein the reacting step comprises
reacting the unsaturated triacylglycerol oil with an olefinic
hydrocarbon including a diene selected from the group consisting of
cyclopentadiene, alkyl substituted cyclopentadienes, butadiene,
alkyl substituted butadienes, and mixtures thereof.
6. The process of claim 4 wherein the reacting step comprises
reacting the unsaturated triacylglycerol oil with a diene
comprising cyclopentadiene.
7. The process of claim 6 wherein the reacting step comprises
reacting the unsaturated triacyiglycerol oil with a diene further
comprising 1-methylcyclo-pentadiene and 2 -methyl
cyclopentadiene.
8. The process of claim 1 wherein the reacting step comprises
reacting the unsaturated triacylglycerol oil with sufficient
olefinic hydrocarbon to form a cycloaddition product having an
average cycloaddition content of at least about 0.25 adducts per
triacyiglycerol molecule.
9. The process of claim 1 wherein the unsaturated triacylglycerol
oil has an Iodine Value of no more than about 150.
10. The process of claim 1 wherein the reacting step comprises
reacting the olefinic hydrocarbon with an unsaturated
triacylglycerol oil selected from the group consisting of soybean
oil, rapeseed oil, olive oil, sunflower oil, safflower oil, peanut
oil, cottonseed oil, crambe oil, mustard oil, meadowfarm oil,
herring oil, menhaden oil and mixtures thereof.
11. The process of claim 10 wherein the sunflower oil comprises a
high oleic sunflower oil.
12. The process of claim 10 wherein the rapeseed oil comprises a
high oleic canola oil.
13. The process of claim 1 wherein the reacting step comprises
reacting an olefinic hydrocarbon including a diene with an
unsaturated triacylglycerol oil including soybean oil.
14. The process of claim 1 wherein the reacting step comprises
forming a cycloaddition product having an AOM value at least about
50% higher than that of the unsaturated triacylglycerol oil.
15. The process of claim 1 wherein the at least partially
hydrogenating step comprises forming a hydrogenated cycloaddition
product having an AOM value at least about 50% higher than that of
the cycloaddition product.
16. The process of claim 1 wherein the reacting step comprises
reacting the unsaturated triacylglycerol oil with an olefinic
hydrocarbon including a monoolefinic hydrocarbon.
17. A modified unsaturated triacylglycerol oil comprising
triacylglycerols which include at least one unsaturated fatty acyl
chain modified to include a cycloaddition adduct; wherein said
modified vegetable oil stock has a viscosity at 40.degree. C. of no
more than about 200 cP.
18. The modified unsaturated triacylglycerol oil of claim 17 having
an AOM value of at least about 50 hours.
19. The modified unsaturated triacylglycerol oil of claim 17 having
an Iodine Value of no more than about 130.
20. The modified unsaturated triacylglycerol oil of claim 17 having
an active methylene content of no more than about 1.5.
21. A method for producing a lubricant comprising: reacting an
unsaturated triacylglycerol oil with an olefinic hydrocarbon to
form a cycloaddition product including at least one triacylglycerol
cycloaddition adduct.
22. The method of claim 21 wherein the unsaturated triacylglycerol
oil has an Iodine Value of no more than about 140.
23. The method of claim 21 further comprising hydrogenating the
cycloaddition product to form a hydrogenated cycloaddition product
having an Iodine Value reduced by at least about 10 Iodine Value
units with respect to that of the cycloaddition product.
24. The method of claim 21 further comprising blending the
hydrogenated cycloaddition product with a petroleum based lubricant
base stock.
25. A lubricant comprising unsaturated triacylglycerols modified to
have at least one fatty acyl chain including a cycloaddition
adduct.
26. A process for producing a lubricant base stock comprising:
reacting an unsaturated triacylglycerol oil having an Iodine Value
of about 50 to about 150 with an olefinic hydrocarbon to form a
cycloaddition product comprising triacylglycerols which have at
least one unsaturated fatty acyl chain modified to include a
cycloaddition adduct.
27. The process of claim 26 wherein the cycloaddition product has
an AOM value at least about 50% higher than that of the unsaturated
triacylglycerol oil.
28. The process of claim 26 wherein the cycloaddition product has
an active methylene content at least about 10% lower than that of
the unsaturated triacylglycerol oil.
29. The process of claim 26 comprising hydrogenating the
cycloaddition product to produce a hydrogenated cycloaddition
product having an Iodine Value at least about 10% lower than that
of the cycloaddition product.
30. The process of claim 29 further comprising fractionating the
hydrogenated cycloaddition product to produce a fractionating
cycloaddition product having an Iodine Value at least about 10%
higher than that of the hydrogenated cycloaddition product.
31. A lubricant formed by a process comprising: reacting an
olefinic hydrocarbon with an unsaturated triacylglycerol to form a
cycloaddition product comprising a triacylglycerol having at least
one unsaturated fatty acyl chain modified to include a
cycloaddition adduct.
32. The lubricant of claim 31 wherein the process further comprises
at least partially hydrogenating the a cycloaddition product to
form a hydrogenated a cycloaddition product.
33. A method of reducing friction between moving parts comprising
applying a lubricant to at least one of said moving parts, wherein
the lubricant comprises at least one unsaturated triacylglycerol
oil modified to comprise at least one fatty acyl chain including a
cycloaddition adduct.
34. A method of disposing of a used lubricant comprising
biodegrading the used lubricant; wherein the used lubricant is
derived from a lubricant comprising an unsaturated triacylglycerol
modified to have at least one fatty acyl chain including a
cycloaddition adduct.
Description
BACKGROUND OF THE INVENTION
[0001] Vegetable oils are obtainable in large volumes from
renewable resources and in general are characterized as readily
biodegradable or "environmentally friendly". As a result, such oils
and related materials are at least theoretically desirable for use
in a wide variety of applications.
[0002] With respect to use for lubrication purposes, especially as
machine lubricants, vegetable oils have not been fully desirable.
Many vegetable oils do not possess the desired spectrum of
characteristics relating to: viscosity index; pour point; oxidative
stability; compatibility with additives; and, flash
point/volatility among others.
[0003] Vegetable oils, such as a soybean oil ("SBO"), do however
possess many desirable properties for use as a lubricant. In
particular, SBO provides good boundary lubrication, good viscosity,
high viscosity index and high flash point. In addition, SBO is
nontoxic and readily biodegradable. For example, under standard
test conditions (e.g., OCED 301D test method), SBO biodegrades up
to 80% into carbon dioxide and water in 28 days, compared to 25% or
less for typical petroleum-based lubricating fluids.
[0004] However, as exemplified by SBO, two characteristics, which
are often major limitations for the utilization of vegetable oils
as lubricants, relate to stability and low temperature behavior. In
particular, vegetable oils such as SBO often contain substantial
amounts of unsaturation (i.e., one or more carbon--carbon double
bonds distributed along the fatty acyl chains). The sites of
unsaturation may be associated with sufficient oxidative reactivity
to render the oils insufficiently stable for use as lubricants. If
efforts are made to reduce the unsaturation, for example by
hydrogenation, generally undesirable changes in pour point and/or
viscosity index result.
SUMMARY OF THE INVENTION
[0005] The present invention relates to unsaturated triacylglycerol
oils, such as unsaturated vegetable oils. It particularly concerns
modifications of selected vegetable oils to produce liquid products
with preferred properties for use, for example as lubricant base
stocks or in related uses. The unsaturated triacylglycerol oil is
typically derived from plants, such as an oil seed, or an animal,
such as tallow.
[0006] A process for modifying an unsaturated triacylglycerol oil,
such as an unsaturated vegetable oil stock, to enhance its fluidity
and/or oxidative stability is provided. The process includes (i)
reacting the unsaturated triacylglycerol oil with an olefinic
hydrocarbon to form a cycloaddition product and, optionally, (ii)
at least partially hydrogenating the cycloaddition product to form
a hydrogenated cycloaddition product. The cycloaddition product
formed from the reaction with the olefinic hydrocarbon includes
triacylglycerols which have at least one fatty acyl chain modified
to include a cycloaddition adduct. If desired, either the
cycloaddition product or the hydrogenated cycloaddition product may
be fractionated using conventional techniques to alter the spectrum
of modified and unmodifed triacylglycerols present. For example,
the hydrogenated cycloaddition product may be fractionated to
remove at least a portion of the saturated triacylglycerols,
thereby enhancing the fluidity properties of the fractionated
cycloaddition product with respect to the hydrogenated
cycloaddition product.
[0007] Herein, when reference is made to the term "unsaturated
triacylglycerol oil", the intent is to refer to a material
comprising triacylglycerols, whether altered or not, derived from
various plant and animal sources, such as oil seed sources. The
term at least includes within its scope: (a) such materials which
have not been altered after isolation; (b) materials which have
been refined, bleached and/or deodorized after isolation; (c)
materials obtained by a process which includes fractionation of an
unsaturated triacylglycerol oil; and, also, (d) oils obtained from
plant or animal sources and altered in some manner, for example
through partial hydrogenation. It will be understood that the
unsaturated triacylglycerol oil may include a mixture of
triacylglycerols, and a mixture of triacylglycerol isomers. By the
term "triacylglycerol isomers", reference is meant to
triacylglycerols which, although including the same esterified acid
residues, may vary with respect to the location of the residues in
the triacylglycerol. For example, an unsaturated triacylglycerol
oil such as a vegetable oil stock can include both symmetrical and
unsymmetrical isomers of a triglyeride which includes two different
fatty acyl chains (e.g., includes both stearate and oleate
groups).
[0008] Herein, the result of adding an olefinic hydrocarbon to an
unsaturated triacylglycerol oil, such as a vegetable oil stock,
will be referenced as a "cycloaddition product." The term
"cycloaddition product" includes within its scope practices which
involve adding one or more olefinic hydrocarbons (e.g., dienic
and/or monoolefinic hydrocarbons), on an average per molecule
basis, to the unsaturated triacylglycerol oil. As used herein, the
term "cycloaddition adduct" refers to an adduct produced by the
reaction of an olefinic hydrocarbon and a double bond in a fatty
acyl chain of a triacylglycerol. One example of a cycloaddition
adduct is the adduct produced by a Diels-Alder reaction between a
dienic hydrocarbon and a double bond in a triacylglycerol fatty
acyl chain. Of course, it will be understood that the cycloaddition
of the olefinic hydrocarbon will not necessarily be uniform in the
mixture, but rather the result of the cycloaddition may be
cycloaddition to some triacylglycerol molecules, and not to others.
Nor will the cycloaddition product necessarily include the
formation of at least one (on an average molecular basis)
cycloaddition adduct per triacylglycerol molecule. For example, the
cycloaddition product will typically include a number of unmodified
triacylglycerols, i.e., triacylglycerols with fatty acyl chains
lacking a cycloaddition adduct.
[0009] The cycloaddition adducts and hydrogenated cycloaddition
adducts have an oxidative stability (as evidenced by their AOM
value and/or active methylene content) which is increased with
respect to the oxidative stability of the unsaturated
triacylglycerol oil. The pour point of the hydrogenated
cycloaddition adduct is generally less than the pour point of a
product obtained from hydrogenation of the the unsaturated
triacylglycerol oil by a corresponding amount. In some instances,
the pour point of a hydrogenated cycloaddition adduct may even be
reduced with respect to the pour point of the corresponding
unsaturated triacylglycerol oil. The present method typically
reduces the active methylene content of the unsaturated
triacylglycerol oil at least about 10% and preferably by at least
about 25% with respect to that of the corresponding unsaturated
triacylglycerol oil.
[0010] The olefinic hydrocarbons used to form the cycloaddition
product may include a diene and/or a monoolefinic hydrocarbon. The
diene can react with a double bond ("dienophile") in a fatty acyl
chain of a triacylglycerol molecule to form a 4+2 cycloadduct
(Diels-Alder adduct). Similarly, monoolefinic hydrocarbons can act
as a dienophile and react with triacylglycerol molecules having a
fatty acyl chain which includes a diene moiety to form a 4+2
cycloadduct. Suitable monoolefinic compounds include cyclohexene,
propene and butene. Alternatively, one of the double bonds of a
diene such as cyclopentadiene or isoprene can act as a dienophile
and react with a diene moiety within a fatty acyl chain of a
triacylglycerol molecule. The diene moiety may exist naturally in
the fatty acyl chain. More commonly, the double bonds of a
polyunsaturated fatty acyl chain may be isomerized (e.g., by
heating and/or by the addition of a catalyst such a iodine) to form
a conjugated diene group within the chain. The olefinic
hydrocarbons typically have a molecular weight of up to about 250
and preferably include no more than about 12 carbon atoms.
[0011] Lubricants including unsaturated triacylglycerols modified
to have at least one fatty acyl chain including a cycloaddition
adduct and processes of producing the lubricants are also provided
herein. The process of producing the lubricant may also include
blending the modified unsaturated triacylglycerols with one or more
petroleum based lubricating fluids and/or other additives.
DETAILED DESCRIPTION
[0012] The present method may be utilized to increase the fluidity
and/or enhance the oxidative stability of unsaturated
triacylglycerol oils. For example, the method allows the production
of vegetable oil based lubricants which, in addition to possessing
very attractive lubricating properties, are extremely
environmentally friendly. Since unsaturated triacylglycerol oil
based lubricant base stocks are derived from natural materials,
these lubricants have low toxicity and are readily biodegraded.
I. Properties of Unsaturated Triacylglycerol Oils
[0013] A unsaturated triacylglycerol oil includes triacylglycerol
molecules (sometimes termed triglycerides). In general,
triacylglycerols comprise three long fatty acid chains esterified
to glycerol; or, alternatively phrased, glycerol esterified by
addition thereto of three long chain fatty acids. Herein, the terms
"triacylglycerols" and "triglycerides" are intended to be
interchangeable, and will in some instances be referred to by the
abbreviation "TG".
[0014] Unlike petroleum-based lubricants, triacylglycerols have
slight polarity on one end of the molecule due to the presence of
the ester linkages. In some instances, this can be desirable when
the material is used as a lubricating fluid, since the polar end of
triacylglycerol molecules can become attracted to a metallic
surface, while the nonpolar hydrocarbon region will generally
project outwardly from metallic surfaces. This causes, in some
instances, molecular attraction and alignment, and can result in
better boundary lubrication with increased load carrying capacity
and reduction in wear.
[0015] As indicated above, any given triacylglycerol molecule
generally includes glycerol esterified with three fatty acid
molecules. Thus, each triacylglycerol includes three fatty acid
residues. In general, oils extracted from any given plant or animal
source comprise a mixture of triacylglycerols, characteristic of
the specific source. The mixture of fatty acids isolated from
complete hydrolysis of the triacylglycerols in a specific source
are generally referred to as a "fatty acid composition". By the
term "fatty acid composition" reference is made to the identifiable
fatty acid residues in the various triacylglycerols. The
distribution of specific identifiable fatty acids is typically
characterized by the amounts of the individual fatty acids as a
weight percent of the total mixture of fatty acids obtained from
hydrolysis of the particular oil stock.
[0016] For example, a typical fatty acid composition of soybean oil
("SBO") is as shown in Table I below.
1TABLE I Typical SBO Fatty Acid Composition Fatty acid Weight
Percent.sup.1 Palmitic acid 10.5 Stearic acid 4.5 Oleic acid 23.0
Linoleic acid 53.0 Linolenic acid 7.5 Other 1.5 .sup.1Weight
percent of total fatty acid mixture derived from hydrolysis of
soybean oil.
[0017] Palmitic and stearic acids are saturated fatty acids and
triacylglycerol acyl chains formed by the esterification of either
of these acids do not contain any double carbon--carbon bonds.
However, many fatty acids such as oleic acid, linoleic acid and
linolenic acid are unsaturated. Oleic acid is an 18 carbon fatty
acid with a single double bond; linoleic acid is an 18 carbon fatty
acid with two double bonds or points of unsaturation; and linolenic
is an 18 carbon fatty acid with three double bonds. More
specifically,
[0018] oleic acid is (Z)-9-octadecanoic acid;
[0019] linoleic acid is (Z,Z)-9,12-octadecadienoic acid;
[0020] linolenic acid is (Z,Z,Z)-9,12,15-octadecatrienoic acid;
and
[0021] .gamma.-linolenic acid is the (Z,Z,Z)-6,9,12 isomer of
octadecatrienoic acid.
[0022] The average number of double bonds present per
triacylglycerol molecule in an unsaturated triacylglycerol oil is
referred to herein as the "average unsaturation content." The
average unsaturation content of an unsaturated triacylglycerol oil
may be calculated based from the distribution of fatty acids in the
mixture produced by hydrolysis of the triacylglycerols. The
distribution of fatty acids in a particular oil may be readily
determined by methods known to those skilled in the art.
Unsaturated triacylglycerol oils which are particularly suitable
for use as starting materials in the present methods typically have
an average unsaturation content of no more than about 5.0 and,
preferably about 2.5 to about 3.5.
[0023] For example, on average, each triacylglycerol molecule in
SBO contains about 4.5 double bonds, distributed among the various
hydrocarbon chains (three chains in each triacylglycerol molecule),
i.e., SBO has an average unsaturation content of about 4.5. This
results from the fact that SBO includes a mixture of
triacylglycerols and the triacylglycerol molecules of SBO generally
each have a mixture of fatty acid residues.
[0024] Another measure of characterizing the average number of
double bonds present in the triacylglycerol molecules of an
unsaturated triacylglycerol oil is its Iodine Value. The Iodine
Value of a triacylglycerol or mixture of triacylglycerols is
determined by the Wijs method (A.O.C.S. Cd 1-25). The present
method can be used to improve the fluidity and oxidative stability
of unsaturated triacylglycerol oils having a wide range of Iodine
Values. Typically, however, the present methods are employed with
unsaturated triacylglycerol oils, such as vegetable oil stocks,
having an Iodine Value of no more than about 150, preferably about
70 to about 140, and, more preferably, about 80 to about 110.
[0025] For example, soybean oil typically has an Iodine Value of
about 125 to about 135 and a pour point of about 0.degree. C. to
about -10.degree. C. Hydrogenation of soybean oil to reduce its
Iodine Value to about 90 or less can significantly improve its
oxidative stability. Hydrogenated soybean oils with this level of
Iodine Value, however, generally have substantially decreased
fluidity as evidenced by an increase in pour point to about 10 to
20.degree. C. or higher and can become solids at room temperature
thereby limiting their use as a functional fluid.
[0026] During use and/or storage lubricants tend to break down due
to oxidation or other degradation processes. When employed as a
functional fluid, such as a lubricating fluid, a vegetable oil like
soybean oil may oxidize during which polymerization and degradation
occurs. Polymerization increases viscosity and reduces lubrication
functionality. Degradation leads to breakdown products that may be
volatile or corrosive. In either case, undesirable modifications to
the lubricating characteristics of the fluid occur.
[0027] One measure of the oxidative stability of an unsaturated
triacylglycerol oil is its "AOM value" (as determined by A.O.C.S.
Method Cd 12-57) or Oil Stability Index (as determined by A.O.C.S.
Cd 12b-92) converted to AOM hours. The AOM value is measured by
passing a controlled flow of air through a heated sample of the
oil. The generation of oxidation products typically includes an
induction phase followed by a large increase in the rate of
oxidation. The length of time (to the nearest hour) required for a
sample of an oil to attain the specified peroxide value of A.O.C.S.
Method Cd 12-57 is reported as the AOM value. The cycloaddition
products and hydrogenated cycloaddition products produced by the
present method preferably have an AOM value of at least about 50
hours and, more preferably, at least about 100 hours.
[0028] The conditions of lubricating fluid storage and/or use,
which may involve exposure to substantial heat; pressure; metal
surfaces, etc., can facilitate the oxidation process. It is
desirable, then, to use lubricating fluids which are not readily
susceptible to undesirable levels of oxidation, at least under
normal storage and use conditions. Unsaturated fatty acyl chains
are more readily susceptible to oxidation than saturated fatty acyl
chains. Thus, triacylglycerols such as those found in soybean oils,
which contain substantial amounts of oleic acid, linoleic acid
and/or linolenic acid residues, can be subject to undesirable
levels of oxidation.
[0029] The undesirable levels of oxidative instability are
presently believed to be due in large part to the presence of
polyunsaturated fatty acyl chains that contain "active methylene
groups." As used herein, active methylene groups refers to
--CH.sub.2-- groups which are situated between two double bonds in
a fatty acyl chain, i.e., doubly allylic --CH.sub.2-- groups. When
found, the active methylene groups are typically present in dienic
and trienic polyunsaturated fatty acyl chairs. Active methylene
groups are principally present in polyunsaturated fatty
acid-containing triacylglycerol molecules, e.g., linoleic esters
(with one active methylene group) and linolenic esters (with two
active methylene groups). The term "active methylene content" as
used herein refers to the average number of active methylene groups
per triacylglycerol molecule in an unsaturated triacylglycerol oil.
The active methylene content of an unsaturated triacylglycerol oil
can be calculated based from the fatty acid composition of the
unsaturated triacylglycerol oil.
[0030] It has been found that the oxidative stability, particularly
as it relates to lubricating applications, of an unsaturated
triacylglycerol oil is substantially enhanced if the Diels-Alder
modified vegetable oil stock has an active methylene content of no
more than about 1.5, preferably no more than about 1.0 and, more
preferably, no more than about 0.5. For example, hydrogenation of a
soybean oil/cyclopentadiene adduct to reduce its active methylene
content to no more than about 1.0 can enhance the oxidative
stability of the hydrogenated adduct with respect to the
unhydrogenated adduct.
[0031] Of course, the propensity for a triacylglycerol to oxidize
can also be reduced by hydrogenation of the double bond(s). That
is, as the extent of hydrogenation increases (and the Iodine Value
and active methylene content decrease), the propensity toward
oxidation decreases. Unfortunately, however, hydrogenation
generally is accompanied by concomitant, and undesirable, increase
in "pour point", i.e., reduction in the fluidity of the oil. For
example, a saturated monoacid triacylglycerol, tristearin (the
stearic acid triester of glycerol; stearic acid is octadecanoic
acid; C.sub.18H.sub.36O.sub.2), has a melting point of 74.degree.
C., compared to triolein's 5.degree. C. and trilinolein's
-11.degree. C.
[0032] It is apparent, then, that one cannot simply hydrogenate an
unsaturated triacylglycerol oil such as soybean oil to obtain an
oxidatively stable lubricating fluid. Thus, although soybean oil
exhibits many properties desirable in a lubricating fluid, it has
generally not been acceptable due to its propensity toward
oxidation, and if hydrogenated, its undesirable levels of loss of
fluidity (or increase of pour point).
[0033] In general, similar affects are observed with a variety of
vegetable oils. For example, palm oil, which has a low average
unsaturation content (e.g., an Iodine Value of about 50 to 60), is
a semi-solid at room temperature and is generally not useful as a
lubricant despite its relatively good oxidative stability. On the
other hand, linseed oil, which has a very high level of
polyunsaturation (fatty ester groups containing more then one
double bond) and an Iodine Value of 170 to 180, has a high pour
point due to the propensity of the polyunsaturated fatty acyl
chains to crosslink and/or polymerize. Due to the propensity of
linseed oil to crosslink or polymerize, unsaturated triacylglycerol
oils used to produce a lubricant base stock by the present methods
typically due not include a significant amount of linseed oil,
e.g., less than about 25 wt. %, preferably no more than about 10
wt. %, and most preferably are substantially free (i.e., less than
about 0.1 wt. %) of linseed oil.
[0034] Because of the tendency of unsaturated triacylglycerol oils
having very high levels of polyunsaturation to polymerize, plant or
animal derived oil stocks having an active methylene content of no
more than about 3.0 and/or an Iodine Value of no more than about
150 are typically used to produce lubricant base stocks using the
present method. Preferably, the unsaturated triacylglycerol oil has
an active methylene content of no more than about 2.5, preferably
no more than about 2.0 and/or includes no more than about 15 wt. %
(on a fatty acid composition basis), preferably no more than about
10 wt. %. of trienic (i.e., having three double bonds) unsaturated
fatty ester groups, such as esters of linolenic acid.
II. Modifications to Unsaturated Triacylglycerol Oils for Use as
Lubricating Fluids
[0035] A. General.
[0036] The fluidity of a material is in part determined by the
ability of molecular packing, intermolecular interactions, and
molecular weight. In general, increasing branching of a
hydrocarbon, especially towards the methyl end, or introducing
unsaturation in the chain (cis typically produces a greater effect
than trans), increases fluidity since it disrupts packing. By
"increase in fluidity" in this context, reference is meant to
reduction in "pour point" or "melting point". The term "pour point"
as used herein refers to the temperature at which the material
stops flowing (as measured by ASTM method D 97). Thus pour point is
a property which may involve a phase change but generally is based
on a change in the viscosity properties of the material. The term
"melting point" as used herein refers to the temperature at which a
material transforms from a solid to a liquid, i.e., when a phase
change involving a heat of fusion occurs.
[0037] In addition to pour point, the viscosity of an unsaturated
triacylglycerol oil or modified version thereof at room temperature
or an elevated temperature (e.g., 40.degree. C.) may be used to
characterize its fluidity. Unless otherwise indicated, viscosities
reported herein are in centipoise (cP) as determined using a
Brookfield viscometer type R.V.F. at a 20 rpm setting. The present
cycloaddition products and hydrogenated cycloaddition products
typically have a viscosity at 40.degree. C. of no more than about
200 cP and, preferably, no more than about 100 cP.
[0038] For some lubricants, the desired fluidity properties may be
specified in terms of a viscosity index (as determined by ASTM
method D 2270). It is characteristic of triglyceride oils that
their viscosity fluctuations as a function of temperature change to
a lesser extent than the viscosities of petroleum based mineral
oils. The viscosity-to-temperature properties of each oil can be
characterized in terms of the viscosity index ("VI"). A higher
viscosity index signifies that the viscosity of the oil concerned
changes less as a function of changes in temperature. The viscosity
indexes of triglycerides (typically in the range of about 180 to
about 275) are clearly higher than those of petroleum based mineral
oils with no additives (typically 50-120), so that triglycerides
are to their nature so-called multigrade oils. This is a
considerable importance under conditions in which the operating
temperature may vary within rather wide limits. The modified
unsaturated triacylglycerol oils produced by the present methods
generally have a viscosity index which is quite similar to the
original triacylglycerol oil. Preferably, the present modified
unsaturated triacylglycerol oils have a viscosity index of at least
about 150 and, more preferably, at least about 175. This is
typically achieved by selecting a starting unsaturated
triacylglycerol oil which has close to the viscosity index desired
for the modified product.
[0039] As part of the development of the present techniques, it was
theorized that triacylglycerols having therein substantial sites of
unsaturation could be improved, with respect to fluidity, by
generation of "spacer groups" or moieties extending from at least
some of the long acyl chains. It was foreseen that such "spacer
groups" would limit the ability for the fatty acyl chains to pack
closely. At the same time, a spacer group generated via a
Diels-Alder reaction would move a double bond from the acyl chain
backbone to a remote position (i.e., into a portion of a ring
extending from the acyl chain backbone). This can create at least
two benefits: (i) a decrease in the possibility of double bond
migration to generate a less stable polyunsaturated chain, e.g.,
through the formation of a conjugated diene or triene fatty acyl
chain; and (ii) the bicyclic nature of the adduct results in the
oxidation products of the remote double bond being non-volatile.
Thus, it was theorized that if, after spacer group introduction,
the triacylglycerols were partially or fully hydrogenated, a
desirable lubricating fluid could result which would possess
appropriate characteristics with respect to both stability towards
oxidation and, desirably, low pour point or melting point.
[0040] B. Cycloaddition Adducts
[0041] Modification of unsaturated triacylglycerol oils through
formation of a cycloaddition product and, optionally, subsequent
hydrogenation of the cycloaddition product can increase the
oxidative stability with respect to the unmodified vegetable oil
stock, e.g., increase the AOM value by at least about 50%.
Preferably, the formation of a cycloaddition product and/or the
subsequent hydrogenation reaction can be used to increase the AOM
value of an unsaturated triacylglycerol oil by a factor of at least
about 2 (i.e., increased by at least about 100%) with respect to
the unmodified unsaturated triacylglycerol oil.
[0042] It has been found that cycloaddition reactions may be used
to modify unsaturated triacylglycerol oils to improve their
properties as lubricating fluids. It can be theorized that when an
olefinic hydrocarbon, such as a diene, is reacted with vegetable
oil having an unsaturation therein, a carbon--carbon double bond or
point of unsaturation in the unsaturated triacylglycerol oil can
act as a dienophile and cycloadd to the conjugated diene by means
of a [4+2] cycloaddition, or Diels-Alder reaction.
[0043] Cyclopentadiene is a well-known active diene, for the
conduct of [4+2] cycloadditions. Indeed, cyclopentadiene will add
to itself, in a dimerization, via a [4+2] cycloaddition, to form,
as a Diels-Alder adduct, dicyclopentadiene. This is a reversible
reaction which can be used to generate cyclopentadiene in situ,
upon application of heat to dicyclopentadiene. For example, two
molecules of cyclopentadiene can be reversibly generated from
dicyclopentadiene at temperatures above about 170.degree. C. In one
embodiment of the invention, a vegetable oil stock such as SBO is
heated at about 200 to about 300.degree. C. in the presence of
dicyclopentadiene. Under such conditions) rather than reacting with
another cyclopentadiene molecule to reform dicyclopentadiene, a
cyclopentadiene molecule can react with a fatty ester double bond
to form a triacylglycerol/cyclopentadiene cycloadduct. This
typically occurs when the concentration of cyclopentadiene present
at any one time during the reaction are relatively low. Under such
conditions, the cyclopentadiene may be relatively efficiently
trapped by reaction with a double bond in a triacylglycerol fatty
acyl chain before the cyclopentadiene has an opportunity to react
with a second molecule of cyclopentadiene.
[0044] Cyclopentadiene, it has been found, readily adds to points
of unsaturation in vegetable oils. In Scheme 1, an example is
provided. of course, reactions with substituted cyclopentadienes
(e.g., alkyl substituted cyclopentadienes such as
1-methylcyclopentadiene and 2-methylcyclopentadiene) are also
feasible, as illustrated in Scheme 1. 1
[0045] As illustrated in Scheme 1, a diene such as cyclopentadiene
or 2-methylcyclopentadiene can with a double bond in one of the
fatty acyl chains of a triacylglycerol. The reaction may occur at
with a double bond in either a fatty acyl chain esterified at a
primary hydroxyl group of the glycerol (e.g., the cyclopentadiene
adduct shown in Scheme 1) or in a fatty acyl chain chain esterified
at a secondary hydroxyl group of the glycerol (e.g., the
2-methylcyclopentadiene adduct shown in Scheme 1). The formation of
a cycloadducts does not alter the Iodine Value or average
unsaturation content of an unsaturated triacylglycerol oil, i.e.,
the number of double bonds present per triacylglycerol molecule may
remain unchanged. The number of active methylene groups present
can, however, be reduced by cycloaddition of an olefinic
hydrocarbon to a polyunsaturated fatty acyl chain. For example, the
reaction of cyclopentadiene with the C12-double bond of a linolenic
ester chain as shown in Scheme 1, destroys the allylic character of
two methylene groups (at both the 11 and 14 positions). The new
double bond present in the bicyclic ring moiety also provides a
potential oxidation site, but the resulting oxidation product
maintains the integrity of the molecule. Moreover, as discussed
herein, it is believed that the introduction of bulky bicyclic
rings onto acyl chains of triacylglycerols leads to a cycloaddition
product having a low viscosity.
[0046] As illustrated in Scheme 1, there are a variety of
cycloadducts that can be formed from the reaction of a single diene
with a unsaturated triacylglycerol oil. It is expected that
reaction between the diene and an unsaturated triacyglycerol could
occur at one or more of a number of positions along a fatty acyl
chain. The reaction may also occur with double bonds on one or more
of the fatty acyl chains within a triacylglycerol molecule.
[0047] If a further improvement in the oxidative stability of a
cycloaddition product is desired, it is generally not necessary to
exhaustively hydrogenate the cycloaddition product. Typically,
hydrogenation of the cycloaddition product sufficiently to reduce
the active methylene content by at least about 10% will produce an
observable improvement in oxidative stability. Preferably, the
cycloaddition product is hydrogenated to a sufficient degree to
decrease the active methylene content by at least about 0.25 and,
preferably, to decrease the active methylene content to a value of
no more than about 0.5. Most preferably, the hydrogentation is
carried out to a sufficient amount to substantially eliminate all
of the allylic methylene groups (i.e., to reduce the active
methylene content of the cycloaddition product to no more than
about 0.1). In the process of eliminating the allylic methylene
postions, an even larger number of isolated double bonds are also
typically eliminated. Stated otherwise, the hydrogenation reaction
will typically reduce the average unsaturation content of the
cycloaddition product by an even larger amount than the observed
reduction in active methylene content. The introduction of the
bulky bicyclic moieties allows the hydrogenatation reaction to be
carried out to a much greater extent without the substantial losses
in viscosity properties that would be expected upon hydrogenation
of the original unsaturated triacyglycerol oil.
[0048] The cycloaddition reaction to produce a cycloaddition
product can be carried out in a number of ways as illustrated by
the following discussion of the production of a SBO/cyclopentadiene
product. The SBO/cyclopentadiene adduct may be produced by a
variety of methods which at least include (i) adding
dicyclopentadiene to the SBE, (ii) simultaneously mixing the
ingredients into a reaction vessel or (iii) separately cracking
dicyclopentadiene to generate cyclopentadiene and then adding the
cyclopentadiene to a reaction vessel containing the SBO. By way of
example, the SBO/dicyclopentadiene adduct may be made by charging
the SBO into a closed reactor purged with an inert gas such as
nitrogen. The SBO is heated to about 260.degree. C. with constant
stirring which is continued throughout the reaction with
dicyclopentadiene. Dicyclopentadiene is typically added at a steady
rate under the surface of the heated SBO in the reactor. While not
intending to be bound by any theory, it is believed that as the
dicyclopentadiene enters the vessel the dicyclopentadiene
dedimerizes into two molecules of cyclopentadiene and which then
reacts with the SBO double bonds. After the addition of the
dicyclopentadiene is completed, heating of the reaction mixture is
generally continued at a temperature of not more than 300.degree.
C., and preferably not more than about 275.degree. C. for about
0.25 hour to about 5 hours. The reaction is generally permitted to
proceed until substantially all of the cyclopentadiene has reacted
with the SBO to form cycloadducts. Thereafter the copolymer
reaction product is cooled and removed from the reaction vessel.
Optionally, the volatile components left in the reaction vessel may
be removed by applying a vacuum (e.g., less than about 50 mm Hg)
during about the last 30 minutes to about the last hour of the
reaction.
[0049] The cycloaddition reaction, it is believed, has at least two
beneficial affects. First, it helps to reduce the susceptability of
the unsaturated triacylglycerol oil to oxidation. A manner in which
this occurs, is that the presence of active methylene groups, for
example, the number of doubly allylic hydrogens (positioned in
methylene groups bonded to two vinyl groups), is reduced. In
addition, the presence of the resulting cycloaddition moiety in the
fatty acyl chains appears to decrease the ease of packing and thus
helps to maintain a low pour point or melting point, even after
significant levels of hydrogenation.
[0050] It is important to recognize that in commercial practice of
the techniques described herein, the techniques will typically be
operated on mixtures of triacylglycerols either isolated as a plant
or animal oil, e.g., by various oil seeds processing techniques, or
resulting from alteration of such oils, for example by prior
partial hydrogenation.
[0051] Herein, when it is said that the "unsaturated
triacylglycerol oil" contains an average of at least one double
bond per triacylglycerol (or triacylglycerol) molecule therein
("unsaturation content"), reference is meant to the average double
bond presence in the triacylglycerol mixture, on a per
triacylglycerol molecule basis. Unmodified SBO, as indicated above,
generally contains an average of about 4.5 double bonds per
molecule. Examples of other unmodified vegetable oils and fish oils
include those listed in Table II below (together with typical
Iodine Values for the oils). Of course, the "unsaturated
triacylglycerol oil" is employed in applications according to the
present invention may comprise a mixture of oils from a variety of
sources.
2 TABLE II Unsaturated Triacylglycerol Oil Iodine Value Rapeseed
oil 97-108 Corn oil 103-128 Peanut oil 84-100 Safflower oil 140-150
Olive oil 80-88 Sunflower oil 125-136 Cottonseed oil 99-113
Menhaden oil 150-160 Herring oil 115-160
[0052] When it is intended that the triacylglycerol is to act as
the diene component in the cycloaddition reaction, the starting
unsaturated triacylglycerol oil may be subjected to an
isomerization reaction to convert the polyunsaturated fatty acyl
chains into conjugated isomers. A conjugation catalyst, such as
ruthenium, rhodium, nickel or compounds thereof, sulfur dioxide,
iodine or a compound capable of generating iodine, may employed in
the this process. Compounds capable or generating iodine include,
for example, hydriodic acid, iodine mono-chloride, iodine
trichloride and iodine mono-bromide. When sulfur dioxide is the
catalyst, it is typically added as the free compound. When nickel
is the catalyst, it is typically used as an activated nickel on
carbon catalyst.
[0053] In carrying out this isomerization reaction, the unsaturated
triacylglycerol oil is typically heated with the catalyst at a
temperature of about 200.degree. C. to 270.degree. C. in the
presence of about 0.001% to 1.5% by weight (based on unsaturated
triacylglycerol oil) of the catalyst. With soybean oil, conjugation
times of 20-30 minutes typically produce about 35% conjugated
linoleic acids.
[0054] Herein, in connection with hydrogenation of the
cycloaddition product, reference will in some instances be made to
"at least partially hydrogenating". By this, it is meant that the
mixture including cycloaddition adduct and any unreacted (via
cycloaddition) triacylglycerol is treated under appropriate
conditions to reduce at least some of the double bonds present by
addition of hydrogen thereacross. In order to be considered "at
least partially hydrogenated" as the term is used herein, there
should be a reduction of at least 10%, and preferably at least
about 25% of the total number of double bonds (on an average per
molecule basis for the whole cycloaddition product). The term "on
an average per molecule basis" in this connection, is meant to
refer to on an average per total of triacylglycerol molecules in
the reaction mixture, whether those molecules includes a
cycloaddition adduct or are an unreacted triacylglycerol
molecule.
[0055] From the above, it will be understood that the intent is to
reference techniques that may be practiced on mixtures, without
precise analysis of exact adduct and unreacted triacylglycerol
presence in the mixture, but rather with a general understanding of
overall diene take-up and, optionally, hydrogen take-up, during
modification. The intent, in general, is to obtain a stock of
desirable property with respect to, inter alia, pour point and
stability. In some instances, this may involve partially
hydrogenating a mixture of: unsaturated triacylglycerol oil which
has previously been treated with diene; and, unsaturated
triacylglycerol oil which has not been previously treated with
diene. In other instances, it may comprise partially hydrogenating
a mixture of more than one unsaturated triacylglycerol oil which
has been differently treated with diene; or, unsaturated
triacylglycerol oils from different sources which have been
similarly treated with diene; etc. Indeed, it is foreseen that in
some applications blends may well be desirable, depending on the
use to which the lubricating stock is to be placed. The present
method is particularly useful for producing lubricant base stocks
which include a predominant amount of a modified unsaturated
triacylglycerol oil, e.g., a lubricant base stock including at
least about 50 wt. % and, preferably, at least about 75 wt. % of
the modified unsaturated triacylglycerol oil. By employing the
present method, biodegradable, unsaturated triacylglycerol
oil-based base stocks which have a combination of oxidative
stability and viscosity properties suitable for a variety of
lubricant applications. Preferred embodiments of the invention
include such base stocks having an oxidative stability
characterized by an AOM value of at least about 50 hours,
preferably at least about 100 hours, and/or an active methylene
content of no more than about 1.5 and, preferably, no more than
about 1.0. Such preferred base stocks typically have fluidity
properties characterized by a viscosity index of at least about 150
and a viscosity at 40.degree. C. of no more than about 200 cP and,
preferably, no more than about 100 cP.
[0056] 1. Some Preferred Vegetable Oils.
[0057] Techniques according to the present invention, as will be
understood from the experimental report below, were particularly
developed for generation of desirable lubricating fluids from
soybean oils. In general, this is because of the particular level
of unsaturation found in soybean oils, as well as the physical
properties both of starting materials and the final adducts. In
general, improvement is observed if the extent of cycloaddition is
at least 0.5 diene molecules added per soybean oil triacylglycerol
molecule, on average. Generally, reactions to the extent of 0.7 to
1.5 dienes added, per soybean oil triacylglycerol molecule, will be
preferred. This can readily be controlled by judicious choice of
the starting vegetable oil stock, the type and amount of olefinic
hydrocarbon employed and the reaction conditions. More broadly,
improvement in the oxidative stability of an unsaturated
triacylglycerol oil, such as a vegetable oil stock, can be produced
through the cycloaddition of at least about 0.25 olefinic
hydrocarbon molecules on average per triacylglycerol molecule. It
has been found that the cycloaddition up to about 2.0 olefinic
hydrocarbon molecules on average per triacylglycerol molecule can
generally produce a substantial enhancement in the oxidative
stability of the unsaturated triacylglycerol oil.
[0058] Other vegetable oils which, it is foreseen, may be modified
with techniques according to the present invention, include:
rapeseed oil, olive oil, sunflower oil, safflower oil, peanut oil,
cottonseed oil, crambe oil, mustard oil, and meadowfarm oil. As
used herein, "rapeseed oil" includes high erucic acid rapeseed oil
("HEAR") and low erucic acid rapeseed oil ("LEAR" or canola oil).
Variants of some of the other oils listed above are also known,
e.g., high oleic and very high oleic sunflower and canola oils. As
discussed herein, these vegetable oils may be employed in the
present invention as isolated or in altered form, as well as with
oil from a single source or mixtures of one or more of the types of
oils (or altered forms thereof).
[0059] 2. Some Preferred Dienes: Conduct of the Preferred
Cycloaddition.
[0060] At the present time, it is foreseen that cyclopentadiene and
1-alkyl cyclopentadiene or 2-alkyl cyclopentadienes (for example,
1-methyl or 2-methyl cyclopentadienes or mixtures thereof) will be
preferred. Such materials are readily obtainable, easily handled,
and result in the introduction of only hydrophobic (alkyl)
substitution in the soybean oil chains. In addition,
cyclopentadienes are relatively active dienes in cycloaddition
reactions, are relatively easy to control and can be generated in
situ from the "cracking" of the corresponding dicyclopentadiene.
Other dienes which can be used to modify a unsaturated
triacylglycerol oil according to the present invention include
cyclohexadiene and acyclic dienes such as isoprene and
dimethylbutadiene. The olefinic hydrocarbon preferably includes
cyclopentadiene and/or an alkyl substituted cyclopentadiene (e.g.,
cyclopentadiene substituted with a C1-C4 alkyl group). In general,
when the cycloaddition reaction involves the use of
cyclopentadiene, the following conditions will be preferred:
reaction of a sufficient amount of cyclopentadiene to increase the
AOM value of the unsaturated triacylglycerol oil by at least about
10% (e.g., a sufficient amount to form on average about 0.25 to
about 2.0 cycloadducts per triacylglycerol molecule); reaction at a
temperature of at least about 200.degree. C.; and reaction for a
sufficient time to achieve the desired increase in oxidative
stability and/or fluidity; and removal of unreacted olefinic
hydrocarbon at the end of the reaction (e.g., by stripping the
reaction product under vacuum).
[0061] 3. Hydrogenation.
[0062] The cycloaddition adducts, such as a SBO/cyclopentadiene
adduct, can be readily reduced using various techniques, for
example by hydrogenating the adduct with hydrogen in the presence
of a heterogeneous noble or transition metal hydrogenation catalyst
(e.g., a paladium, platinum, nickel, or highly selective
copper-chromium catalyst). Methods and conditions suitable for
hydrogenating the cycloaddition adducts include those typically
employed to hydrogenate vegetable oil stocks, such as soybean oil.
One example of a catalyst suitable for use in hydrogenating the
present cycloaddition adducts, is a nickel catalyst deposited on
the surface of an inert support (e.g., a nickel--carbon catalyst
such as Nysel.RTM., available from Engelhard). The degree of
hydrogenation can be selected by controlling conditions and
monitoring the hydrogenation reaction as it proceeds. In general,
hydrogenation will be conducted until stability of the resulting
oil, with respect to oxidation, has been increased to a desired
level. For example, the hydrogenation of the cycloaddition adduct
is typically allowed to continue until the Iodine Value has been
decreased to no more than about 110, preferably no more than about
90 and/or the active methylene content has been reduced to no more
than about 1.5, preferably no more than about 1.0 and, more
preferably, no more than about 0.5.
III. Some Preferred Products
[0063] A. A Lubricating Fluid Base.
[0064] Techniques according to the present invention can be
utilized to prepare preferred lubricating fluid bases, or base
stocks, from various plant or animal oils. As indicated above, a
soybean oil derivative can be prepared, for example, as a
lubricating base stock. Lubricating base stocks would, in general,
be fluids that can be used as the ingredient present in the highest
amount by weight in a wide variety of lubricating fluids, for
example, as the base fluid stock for crankcase oils, transmission
oils, power transfer fluids (e.g., hydraulic fluids), gear oils and
greases. It is foreseen that such materials may be used as the
lubricating fluid base in such industries as: the automotive
industry, metalworking and metal forming industries, earth moving
industry, and general manufacturing.
[0065] B. Preparation of Lubricating Fluids from the Base
Stock.
[0066] The major constituent of a lubrication fluid is a base oil
(base stock) formulated with small amounts of additives. The base
oil provides the primary lubricant functionality and performance.
The additives enhance the performance of the base oil and also
provide additional advantages and/or remove the shortcomings of the
base oil.
[0067] Once base stocks according to the present invention are
developed, they can be readily converted into lubricating fluid by
the provision therein of appropriate additives. For example, to
make lubricants, such as motor oils, transmission fluids, gear
oils, industrial lubrication oils, metal working oils, and the
like, one typically starts with a lubricant grade of the present
cycloaddition adduct or hydrogenated cycloaddition adduct (referred
to collectively herein as a "cycloaddition adduct base stock").
Into this "base stock" is typically blended a small amount of
specialty chemicals that enhance lubricity, inhibit wear and
corrosion of metals, and retard damage to the fluid from heat and
oxidation.
[0068] Anti-wear agents, extreme pressure agents and friction
modifiers have been developed that are generally organic or
organometallic compounds containing halogens, sulfur, phosphorus,
or a combination of the three. Halogens have noted low-temperature
metal-coating activity but can cause serious corrosion problems at
the higher operating temperatures of motor vehicles or industrial
machinery and have environmental problems upon disposal.
Manufacturers have, therefore, more recently switched to the use of
derivatives of sulfur and phosphorus for lubricant additives in
place of halogen-containing additives.
[0069] The amount and type of additives required in a formulation
depends upon the severity of the application; usually the additives
vary from 5 to 20% of the total formulation. Types of additives
that commonly used in lubricant formulations include: viscosity
index improvers (e.g., a few % polyisobutylenes and/or
polymethacrylates); oxidation inhibitors (e.g., 0.5-1.0%
di-tert-butyl-p-cresol and/or other phenolic antioxidant); pour
point depressants (e.g., circa 1% of a polymethacrylate); antiwear
agents (e.g., a few % of a polar fatty acid compound and/or a
zincdiorganodithiophosphate); detergent dispersants (e.g., 2-20% of
a sulfonate and/or a phosphate); and rust inhibitors (e.g., circa
1% of a mildly polar organic acids, organic phosphates and/or
amines).
IV. Illustrative Experimental Examples
EXAMPLE 1
Soybean Oil/Cyclopentadiene Adduct
[0070] A steel par reactor was charged with 394 g of soybean oil.
After closing and purging the reactor with nitrogen, the reactor
was heated to 260.degree. C. The contents of the reactor were
stirred throughout the heating reaction and cool down periods.
Dicyclopentadiene (30 g) was added to the hot soybean oil over the
period of 1 hour. The reaction was maintained at 260.degree. C. for
an additional 23 minutes after the addition of the
dicyclopentadiene had been completed. The pressure in the reactor
was then released to a cold trap and the vessel was connected to a
pump to strip the volatile components from the vessel. The
stripping was continued for 10 minutes during which 13.2 g of
material were removed from the reactor. After stripping, the
reaction product was cooled to room temperature. The modified
soybean oil product had a pour point of -12.degree. C. and a
viscosity of 55 cP at 39.5.degree. C. (Brookfield Viscometer). The
starting soybean oil had a pour point of -7.degree. C. and a
viscosity of about 30 cP at 40.degree. C.
EXAMPLE 2
Hydrogenated Soybean Oil/Cyclopehtadiene Adduct
[0071] The modified soybean oil product prepared in Example 1 was
placed in a steel parr reactor together with 3.23 g of a Nysel.RTM.
545 nickel catalyst (available from Engelhard). The reactor was
purged under vacuum and then maintained under an atmosphere of 25
psi hydrogen for a period of 3.0 hours. Sample aliquots were
removed for pour point and Iodine Value analysis at 15 minute, 1
hour, 1.5 hour and 2.5 hour intervals after initiation of the
reaction. The results of these analysis are shown in Table III
below. The final product was a semi-solid at room temperature and
had a viscosity of 75 cP at 40.degree. C. (Brookfield
Viscometer).
3TABLE III Time (hr) Iodine Value Pour Point (.degree. C.) 0.25 122
-9 1 76.3 -5 1.5 75.0 0 3.0 72.7 11
EXAMPLE 3
Soybean Oil-Cyclopentadiene Adduct Ii
[0072] Soybean oil (367.5 g) and dicyclopentadiene (55.5 g) were
reacted using the procedure described in Example 1 above. The
cyclopentadiene was added to the soybean oil at 260.degree. C. over
a period of 1 hour. The reaction mixture was heated at 260.degree.
C. for an additional 40 minutes after addition of the
dicyclopentadiene. The mixture was then stripped under vacuum for
10 minutes to yield 413 g of a modified soybean oil product having
a pour point of -4.5.degree. C. and a viscosity of 70 cP at
40.degree. C. (Brookfield Viscometer).
EXAMPLE 4
Hydrogenated Soybean Oil/Cyclopentadienes Adduct II
[0073] The soybean oil/cyclopentadiene adduct produced in Example 3
above (286.6 g) was hydrogenated in the presence of 2.86 g of a
nickel catalyst using the procedure described in Example 2.
Aliquots of the reaction mixture were removed at 0.5, 1.0, 1.5 and
2.0 hours for pour point and Iodine Value analysis. The reaction
was stopped after 2.5 hours. Each of the 5 gram aliquots were mixed
with 100 mg of diatomaceous earth and 1 drop of citric acid and
filtered at 45.degree. C. prior to analysis. The results of the
analysis are shown in Table IV below. The final product had a
viscosity of 82.5 cP at 40.degree. C. (Brookfield Viscometer).
4TABLE IV Time (hr) Iodine Value Pour Point (.degree. C.) 0.5 126.2
-0.5 1.5 84.2 4 2.0 49.7 na 2.5 21.7 10.5
EXAMPLE 5
Tallow/Cyclopentadienes Adduct
[0074] Tallow (395.25 g) and dicyclopentadiene (38.25 g) were
reacted using the procedure described in Example 1 above. The
dicyclopentadiene was introduced to the hot tallow over a period of
64 minutes and the reaction mixture was maintained at 260.degree.
C. for an additional 36 minutes after the addition of the
dicyclopentadiene had been completed. The reaction mixture was
cooled and stripped for 10 minutes during which time 5.4 g of
distillate was removed. The resulting tallow/cyclopentadiene adduct
had a pour point of 25.degree. C. and a viscosity of 67.5 cP at
40.degree. C. (Brookfield Viscometer).
EXAMPLE 6
Hydrogenated Tallow/Cyclopentadienes Adduct
[0075] The tallow/cyclopentadienes adduct of Example 5 (343.5 g)
was hydrogenated in the presence of 3.46 g of a nickel catalyst for
3 hours. The final product had a pour point of 35.degree. C. and an
Iodine Value of 58.2.
EXAMPLE 7
Tallow/Cyclopentadienes Adduct II
[0076] Tallow (372 g) and dicyclopentadiene (29 ml) were reacted
according to the procedure described in Example 1 above. The
dicyclopentadiene was added to the tallow at 260.degree. C. over a
period of 62 minutes. Stripping of the reaction product under
vacuum for a period of 10 minutes resulted in a removal of 8.9 g of
distillate. The final product had a viscosity of 65 cP at
40.degree. C.
EXAMPLE 8
Soybean Oil/Isoprene Adduct
[0077] Soybean oil (381.3 g) and isoprene (28.7 g) were reacted
using a modification of the procedure described in Example 1 above.
The isoprene was mixed with the soybean oil prior to introduction
of the starting material into the reactor. After sealing and
purging the reactor with nitrogen, the reaction mixture was heated
to 260.degree. C. for a period of 2 hours. Stripping of the
reaction mixture resulted in removal of 12 g of distillate. The
resulting soybean oil/isoprene adduct had a pour point of
-12.degree. C. and an Iodine Value of 139.9.
EXAMPLE 9
Hydrogenated Soybean Oil/Isoprene Adduct
[0078] The soybean oil/isoprene adduct of Example 8 was
hydrogenated according to procedure described in Example 2 above.
The adduct (374 g) was hydrogenated in the presence of 3.74 g of a
nickel/carbon catalyst for a period of 2.5 hours. Aliquots were
removed at half hour intervals for pour point analysis. The results
are shown in Table V below.
5 TABLE V Time (hr) Pour Point (.degree. C.) 0.5 10.5 1.0 27 1.5 33
2.0 39 2.5 45
EXAMPLE 10
Soybean Oil/Isoprene Adduct
[0079] A mixture containing 75 wt. % soybean oil and 25 wt. %
isoprene was reacted by heating for 120 minutes at 260.degree. C.
according to the procedure described in Example 8 above. The
reaction mixture was stripped under vacuum for 25 minutes. The
resulting soybean oil/isoprene adduct had a pour point of
-12.degree. C.
EXAMPLE 11
Soybean Oil/Dimethylbutadiene Adduct
[0080] A mixture containing 92 wt. % soybean oil and 8 wt. %
2,3-dimethylbutadiene were reacted by heating for 110 minutes at
260.degree. C. according to the procedure described in Example 8
above. The reaction product was stripped under vacuum for 10
minutes during which time 2.5 g of distillate were removed.
EXAMPLE 12
Hydrogenated Soybean Oil/ Dimethylbutadiene Adduct
[0081] The soybean oil/dimethylbutadiene adduct prepared in Example
11 (354 g) was hydrogenated in the presence of 3.5 g of a
nickel/carbon catalyst for a period of 1.5 hours. Aliquots of the
reaction mixture were removed at half hour intervals and analyzed
for pour point. The results of the analysis are shown in Table VI
below.
6 TABLE VI Time (hr) Pour Point (.degree. C.) 0.5 24 1.0 39 1.5
43.5
[0082]
7TABLE VII Adduct of Reactant Pour Iodine Viscosity @ Example
Adduct* Ratio Point (.degree. C.) Value 40.degree. C. (cP) 1
SBO/CPD 93/7 -12 127 55 2 SBO/CPD [H] 93/7 14-15 72.7 75 3 SBO/CPD
87/13 .sup.-3-.sup.-6 -- 70 4 SBO/CPD [H] 87/13 10-11 21.7 82.5 5
TALLOW/CPD 91/9 25 67.5 6 TALLOW/CPD [H] 91/9 35 58.2 -- 7
TALLOW/CPD 93/7 -- -- 65 8 SBO/ISP 93/7 .sup.-12.sup. 140 -- 9
SBO/ISP [H] 93/7 45 -- -- 10 SBO/ISP 75/25 .sup.-12.sup. -- -- 11
SBO/DMBD 92/8 -- -- -- 12 SBO/DMBD [H] 92/8 42-45 -- -- SBO --
.sup.-7.sup. 127 -- *SBO--soy bean oil; CPD cyclopentadiene;
ISP--isoprene; DMBD--dimethylbutadiene; [H]--hydrogenated version
of corresponding adduct.
[0083]
8TABLE VII Iodine Pour Unsaturation Active** Sample Value Point
(.degree. C.) Content* AOM (hrs) Methylenes Typical Paraffin 9.25
-5 >169 Hydraulic Fluid SBO 127.3 -7 4.63 12.1 2.09 Plant Hydro
- F2 116.2 -2 4.17 14 1.53 Plant Hydro - F3 105.1 4 18 NA Plant
Hydro - F4 83.9 10 2.96 0.38 Plant Hydro - F5 73.8 14 2.62 0.00
Plant Hydro - F6 69.3 21 2.32 0.00 Plant Hydro - S8 29.7 43 0.93
0.00 SBO:DCPD adduct 93:7 127.2 -12 4.33 81.1 1.94 Adduct Hydro B
(0.16) 122 -9 4.19 1.93 Adduct Hydro C (0.33) -9 4.09 1.90 Adduct
Hydro D (1:00) 76.3 -5 1.53 Adduct Hydro E (1:30) 75 0 3.36 0.86
Adduct Hydro F (2:00) 2 3.17 0.72 Adduct Final (3:00) 72.7 11 2.64
190.6 0.00 *Number of acylchain double bonds per molecule
determined by NMR; **Number of methylenes present in between the
double bonds per molecule determined by NMR (i.e., number of doubly
allylic methlene groups/molecule).
* * * * *