Note: Descriptions are shown in the official language in which they were submitted.
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INDUSTRIAL OIL COMPRISING A BIO-DERIVED ESTER
TECHNICAL FIELD
[001] The application generally relates to industrial oil compositions
comprised of
an ester having a vicinal diester substituent. The use of such esters can
provide biodegradable
industrial oils having high viscosity index.
BACKGROUND
[002] Naphthenic base oils, or pale oils, are produced from feedstocks rich in
naphthenes and low in wax content. Because of their low wax content,
naphthenic base oils
have lower pour points and better additive solvency characteristics than
paraffinic base oils
which make naphthenic oils particularly useful in formulating low temperature
lubricating
oils such as industrial oils. Naphthenic base oils have a low viscosity index
(e.g., 40 to 80)
which makes them less suitable for use in applications where a wide
temperature occurs,
unless expensive viscosity index improvers are added. In addition, naphthenic
base oils have
poor biodegradability and have high aromatics content. Naphthenic base oils
are defined as
Group V base oils according to the American Petroleum Institute (API).
[003] Ester-based lubricants, in general, have excellent lubrication
properties due to
the polarity of the ester molecules of which they are comprised and are
relatively stable to
thermal and oxidative processes. They have characteristics similar to
naphthenic base oils
such as low pour points and good additive solvency. In addition, ester-based
lubricants have
much higher viscosity indexes than naphthenic base oils and have excellent
biodegradability.
[004] Currently, a number of commercial esters are available as lubricants.
These
include mono-esters, diesters, phthalate esters, trimellitate esters and
polyol esters. These
commercial esters are either generally poor lubricants (for one or more of a
variety of
reasons) or relatively expensive.
[005] Recently, novel bio-derived esters have been described, for example, in
U.S.
Patent Nos. 7,544,645; 7,867,959; and 7,871,967. The bio-derived ester
syntheses described
in these patents can render the economics of ester lubricant formations more
favorable.
[006] In view of the foregoing, providing a more economical industrial oil
comprising an ester with improved lubricating properties, particularly wherein
the ester is at
least partially derived from a renewable resource, would be highly desirable.
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SUMMARY
[007] In one aspect, we provide an industrial oil comprising a major amount of
an
ester base oil comprised of at least one diester or triester species having a
vicinal diester
substituent and at least one additive. The industrial oil is selected from the
group consisting
of a hydraulic oil, a rock drill oil, a saw guide oil, and a way oil.
[008] In another aspect, we provide a method for improving an industrial oil
comprising selecting an ester base oil comprised of at least one diester or
triester species
having a vicinal diester substituent; and replacing at least a portion of an
original base oil in
an original industrial oil with the ester base oil to produce an improved
industrial oil, wherein
viscosity index, additive solvency or both of the improved industrial oil is
higher compared to
an original viscosity index, an original additive solvency or both of the
original industrial oil
without the ester base oil. In some embodiments, the original base oil is a
naphthenic base oil.
In some embodiments, the improved industrial oil is substantially free of any
viscosity
improver. In some embodiments, the viscosity index of the improved industrial
oil is at least
50 (e.g., 60, 70, 80, 90 or 100) greater than the original viscosity index of
the original
industrial oil.
DETAILED DESCRIPTION
[009] The following terms will be used throughout the specification and will
have
the following meanings unless otherwise indicated.
[010] The prefix "bio" refers to an association with a renewable resource of
biological
origin, such resources generally being exclusive of fossil fuels. Such an
association is typically
that of derivation, i.e., a bio-ester derived from a biomass precursor
material.
[011] "Vicinal" refers to the attachment of two functional groups (e.g., ester
groups)
to adjacent carbons in a hydrocarbon-based molecule.
[012] "Ci," describes a hydrocarbon molecule or fragment (e.g., an alkyl
group)
wherein "n" denotes the number of carbon atoms in the molecule or fragment.
[013] "Carbon number" is used herein in a manner analogous to that of "C." The
carbon number refers to the total of carbon atoms in a molecule (or fragment)
regardless of
whether or not it is purely hydrocarbon in nature. Laurie acid, for example,
has a carbon
number of 12.
[014] "Kinematic viscosity" is a measurement in mm2/s of the resistance to
flow of a
fluid under gravity, determined by ASTM D445-11 a ("Standard Test Method for
Kinematic
Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic
Viscosity)").
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[015] "Viscosity index" (VI) is an empirical, unit-less number indicating the
effect
of temperature change on the kinematic viscosity of the oil. The higher the VI
of an oil, the
lower its tendency to change viscosity with temperature. Viscosity index is
measured
according to ASTM D2270-10 ("Standard Practice for Calculating Viscosity Index
from
Kinematic Viscosity at 40 and 100 C").
[016] "Pour point" represents the lowest temperature at which a fluid will
pour or
flow. See, e.g., ASTM D97-11 ("Standard Test Method for Pour Point of
Petroleum
Products"), ASTM D5950-02 (Reapproved 2007) ("Standard Test Method for Pour
Point of
Petroleum Products (Automatic Tilt Method)"), and ASTM D6892-03 (Reapproved
2008)
("Standard Test Method for Pour Point of Petroleum Products (Robotic Tilt
Method)").
[017] "Cloud point" represents the temperature at which a fluid begins to
phase
separate due to crystal formation. See, e.g., ASTM D2500-11 ("Standard Test
Method for
Cloud Point of Petroleum Products"), ASTM D5551-95 (Reapproved 2006)
("Standard Test
Method for Determination of the Cloud Point of Oil"), ASTM D5771-10 ("Standard
Test
Method for Cloud Point of Petroleum Products (Optical Detection Stepped
Cooling
Method)") and ASTM D5773-10 ("Standard Test Method for Cloud Point of
Petroleum
Products (Constant Cooling Rate Method)").
[018] "Oxidation stability" generally refers to a composition's resistance to
oxidation. Oxidator BN is a convenient way to measure the oxidation stability
of base oils.
The Oxidator BN test is described in U.S. Patent No. 3,852,207. The Oxidator
BN test
measures the resistance of an oil to oxidation by means of a Dornte-type
oxygen absorption
apparatus. See R.W. Dornte, Ind. Eng. Chem. 1936, 28, 26-30. Normally, the
conditions are 1
atmosphere of pure oxygen at 340 F (171 C). The results are reported in hours
to absorb 1000
mL of 02 by 100 g of oil.
Ester Base Oil
[019] The industrial oil comprises a major amount of an ester base oil
comprised of
at least one diester or triester species having a vicinal diester substituent.
As used herein, the
term "major amount" refers to a concentration of the ester base oil within the
industrial oil of
at least 50 wt. %. The amount of the ester base oil in the industrial oil
ranges from 50 to 99
wt. %, e.g., 60 to 98 wt. %, 70 to 97 wt. %, or 80 to 96 wt. %, based on the
total weight of the
industrial oil.
Diester Species
[020] In some embodiments, the ester base oil comprises a diester species
having the
following chemical structure (1):
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0
R- 0
R1R2 (1)
0
R4
0
wherein Rl, R2, R3, and R4 are independently selected from hydrocarbon groups
having from
2 to 17 carbon atoms.
[021] Regarding the above-mentioned diester species, the selection of R', R2,
R3,
and R4 can follow any or all of several criteria. For example, in some
embodiments, Rl, R2,
R3, and R4 are selected such that the kinematic viscosity at 1000C of the
industrial oil is
typically 3 mm2/s or greater. In some or other embodiments, Rl, R2, R3, and R4
are selected
such that the pour point of the resulting industrial oil is ¨10 C or lower,
¨25 C or lower; or
even ¨40 C or lower. In some embodiments, Rl and R2 are selected to have a
combined
carbon number (i.e., total number of carbon atoms) of from 6 to 14. In these
or other
embodiments, R3 and R4 are selected to have a combined carbon number of from
10 to 34.
Depending on the embodiment, such resulting diester species can have a
molecular mass
between 340 atomic mass units (a.m.u.) and 780 a.m.u.
[022] In some embodiments, the ester base oil is substantially homogeneous in
terms
of its diester species. In some or other embodiments, the ester base oil
comprises a mixture of
diester species.
[023] In some embodiments, the ester base oil comprises at least one diester
species
derived from a C8 to C16 olefin and a C2 to C18 carboxylic acid. The diester
species can be
made by reacting the parent diol (on the intermediate) with different acids to
make mixed
diesters, but such diester species can also be made by reacting the diol with
the same acid.
[024] In some embodiments, the diester species is selected from the group
consisting
of decanoic acid 2-decanoyloxy-1-hexyl-octyl ester and its isomers,
tetradecanoic acid-1-
hexy1-2-tetradecanoyloxy-octyl esters and its isomers, dodecanoic acid 2-
dodecanoyloxy-1-
hexyl-octyl ester and its isomers, hexanoic acid 2-hexanoyloxy-1-hexyl-octyl
ester and its
isomers, octanoic acid 2-octanoyloxy-1-hexyl-octyl ester and its isomers,
hexanoic acid 2-
hexanoyloxy-1-pentyl-heptyl ester and its isomers, octanoic acid 2-octanoyloxy-
1-pentyl-
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heptyl ester and its isomers, decanoic acid 2-decanoyloxy-1-pentyl-heptyl
ester and its
isomers, decanoic acid-2-decanoyloxy-1-pentyl-heptyl ester and its isomers,
dodecanoic acid-
2-dodecanoyloxy-1-pentyl-heptyl ester and its isomers, tetradecanoic acid 1-
penty1-2-
tetradecanoyloxy-heptyl ester and its isomers, tetradecanoic acid 1-buty1-2-
tetradecanoyloxy-
hexyl ester and its isomers, dodecanoic acid-l-buty1-2-dodecanoyloxy-hexyl
ester and its
isomers, decanoic acid 1-butyl-2-decanoyloxy-hexyl ester and its isomers,
octanoic acid 1-
buty1-2-octanoyloxy-hexyl ester and its isomers, hexanoic acid 1-buty1-2-
hexanoyloxy-hexyl
ester and its isomers, tetradecanoic acid 1-propy1-2-tetradecanoyloxy-pentyl
ester and its
isomers, dodecanoic acid 2-dodecanoyloxy-1-propyl-pentyl ester and its
isomers, decanoic
acid 2-decanoyloxy-1-propyl-pentyl ester and its isomers, octanoic acid 1-2-
octanoyloxy-1-
propyl-pentyl ester and its isomers, hexanoic acid 2-hexanoyloxy-1-propyl-
pentyl ester and
its isomers, and mixtures thereof
Processes for Making the Diester
[025] Methods which can be employed in making the diester species are further
described in U.S. Patent Nos. 7,867,959 and 7,871,967 and U.S. Patent
Application
Publication Nos. 2010/0120642; 2010/0261627; and 2011/0077184.
[026] More specifically, in some embodiments, the process for making the above-
mentioned diester species, comprises the following steps: (a) epoxidizing an
olefin (or
quantity of olefins) having from 8 to 16 carbon atoms to form an epoxide; (b)
hydrolyzing the
epoxide to form a diol; and (c) esterifying (i.e., subjecting to
esterification) the diol with an
esterifying agent having from 2 to 18 carbon atoms to form the diester
species, wherein the
esterifying agent is selected from the group consisting of carboxylic acids,
acyl halides, acid
anhydrides, and combinations thereof The diester species has a kinematic
viscosity at 100 C
of 3 mm2/s or more.
[027] In some embodiments, the diester species can be prepared by epoxidizing
an
olefin having from 8 to 16 carbon atoms to form an epoxide. The epoxide is
reacted directly
with an esterifying agent having from 2 to 18 carbon atoms to form the diester
species,
wherein the esterifying agent is selected from the group consisting of
carboxylic acids, acyl
halides, acid anhydrides, and combinations thereof The diester species has a
viscosity and a
pour point suitable for use as an industrial oil.
[028] In some embodiments, where a quantity of the diester species is formed,
the
quantity of the diester species can be substantially homogeneous, or it can be
a mixture of
two or more different diester species.
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[029] In some embodiments, the olefin is a reaction product of a Fischer-
Tropsch
process. In some embodiments, the olefin is a mixture of isomeric olefins
and/or a mixture of
olefins having a different number of carbon atoms. In some embodiments, the
carboxylic acid
can be derived from alcohols generated by a Fischer-Tropsch process and/or it
can be a bio-
derived fatty acid.
[030] In some embodiments, the olefin is an alpha olefin (i.e., an olefin
having a
double bond at a chain terminus). It is sometimes necessary to isomerize the
alpha olefin so
as to internalize the double bond. Such isomerization can be carried out using
a catalyst such
as, but not limited to, crystalline aluminosilicate and like materials and
aluminophosphates.
See, e.g., U.S. Patent Nos. 2,537,283; 3,211,801; 3,270,085; 3,327,014;
3,304,343;
3,448,164; 3,723,564; 4,593,146; and 6,281,404.
[031] For example, Fischer-Tropsch alpha olefins can be isomerized to the
corresponding internal olefins followed by epoxidation. The epoxides can then
be
transformed to the corresponding diols via epoxide ring opening followed by di-
acylation
(i.e., di-esterification) with the appropriate carboxylic acids or their
acylating derivatives. It is
sometimes necessary to convert alpha olefins to internal olefins because
diesters of alpha
olefins, especially short chain alpha olefins, can tend to be solids or waxes.
"Internalizing"
alpha olefins followed by transformation to the diester functionalities
introduces branching
along the chain which reduces the pour point of the intended products. It is
typically
preferable to have a few longer branches than many short branches, since
increased branching
tends to lower the viscosity index.
[032] Regarding the step of epoxidizing (i.e., the epoxidation step), in some
embodiments, the above-described olefin (in one embodiment, an internal
olefin) can be
reacted with a peroxide (e.g., H202) or a peroxy acid (e.g., peroxyacetic
acid) to generate an
epoxide. See, e.g., D. Swern, in Organic Peroxides Vol. II, Wiley-
Interscience, New York,
1971, 355-533; and B. Plesnicar, in Oxidation in Organic Chemistry, Part C, W.
Trahanovsky (ed.), Academic Press, New York 1978, 221-253. Olefins can be
efficiently
transformed to the corresponding vicinal diols by highly selective reagents
such as osmium
tetroxide or potassium permanganate (see, e.g., A.H. Haines, Methods for the
Oxidation of
Organic Compounds: Alkanes, Alkenes, Alkynes, and Arenes, Academic Press,
London,
1985, 75-91).
[033] Regarding the step of hydrolyzing the epoxide to form the corresponding
diol,
this step can be acid-catalyzed or base-catalyzed. Exemplary acid catalysts
include, but are
not limited to, mineral-based Bronsted acids (e.g., HC1, H2504, H3PO4,
perhalogenates, etc.),
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Lewis acids (e.g., TiC14 and A1C13), solid acids such as acidic aluminas and
silicas or their
mixtures, and the like. See, e.g., R.E. Parker et al., Chem. Rev. 1959, 59,
737-799. Base-
catalyzed hydrolysis typically involves the use of bases such as aqueous
solutions of sodium
or potassium hydroxide.
[034] Regarding the step of esterifying (esterification) the diol, an acid is
typically
used to catalyze the reaction between the hydroxyl groups of the diol and the
carboxylic
acid(s). Suitable acids include, but are not limited to, sulfuric acid (see,
e.g., J. Munch-
Petersen, Org. Syntheses, Coll. Vol. 5, 1973, p. 762), a sulfonic acid (see,
e.g., C.F.H. Allen
et al., Org. Syntheses, Coll. Vol. 3, 1955, p. 203), hydrochloric acid (see,
e.g., E.L. Eliel et
al., Org. Syntheses, Coll. Vol. 4, 1963 p. 169), and phosphoric acid (among
others). In some
embodiments, the carboxylic acid used in this step is first converted to an
acyl chloride (via,
e.g., thionyl chloride or PC13). Alternatively, an acyl chloride could be
employed directly.
When an acyl chloride or an acid anhydride is used as an esterifying agent, a
base such as
pyridine, 4-dimethylaminopyridine (DMAP) or triethylamine (TEA) can be added
to
accelerate the rate of the reaction. When pyridine or DMAP is used, it is
believed that these
amines also act as a catalyst by forming a more reactive acylating
intermediate (see, e.g.,
A.R. Fersht et al., J. Am. Chem. Soc. 1970, 92, 5432-5442; and G. Hofle et
al., Angew.
Chem. Int. Ed. Engl. 1978, 17, 569-583).
[035] Regarding the step of directly esterifying an epoxide, in some
embodiments,
this step is carried out in the presence of a catalyst. Such catalysts can
include, but are not
limited to, H3PO4, H2504, sulfonic acids, Lewis acids, silica- and alumina-
based solid acids,
AMBERLYSTTm polymer-based catalysts, tungsten oxide, and mixtures thereof.
[036] Regardless of the source of the olefin, in some embodiments, the
carboxylic
acid used in the above described method is derived from biomass. In some such
embodiments, this involves the extraction of some oil (e.g., triglyceride)
component from the
biomass and hydrolysis of the triglycerides of which the oil component is
comprised so as to
form free carboxylic acids.
Triester Species
[037] In some embodiments, the ester base oil comprises a triester species
having
the following chemical structure (2):
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0
R-2
0
0
R561' R6 (2)
R7 0 0
0
wherein R5, R6, R7, and R8 are independently selected from hydrocarbon groups
having from
2 to 20 carbon atoms, and wherein "n" is an integer from 2 to 20.
[038] Regarding the above-mentioned triester species (2), selection of R5, R6,
R7,
and R8, and "n" can follow any or all of several criteria. For example, in
some embodiments,
R5, R6, R7, and R8 and "n" are selected such that the kinematic viscosity at
100 C of the
industrial oil is typically 3 mm2/s or greater. In some or other embodiments,
R5, R6, R7, and
R8 and "n" are selected such that the pour point of the resulting industrial
oil is ¨10 C or
lower, e.g., ¨25 C or even ¨40 C or lower. In some embodiments, R5 is selected
to have a
total carbon number of from 6 to 12. In these or other embodiments, R6 is
selected to have a
carbon number of from 2 to 20. In these or other embodiments, R7 and R8 are
selected to have
a combined carbon number of from 4 to 36. In these or other embodiments, "n"
is selected to
be an integer from 5 to 10. Depending on the embodiment, such resulting
triester species can
have a molecular mass between 400 a.m.u. and 1100 a.m.u., or between 450
a.m.u. and 1000
a.m.u.
[039] In some of the above-described embodiments, the triester species (2)
used to
prepare the industrial oil comprises one or more triester species of the type
9,10-bis-
alkanoyloxy-octadecanoic acid alkyl ester and isomers and mixtures thereof,
where the alkyl
is selected from the group consisting of ethyl, propyl, butyl, pentyl, hexyl,
heptyl, octyl,
nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl,
and octadecyl;
and where the alkanoyloxy is selected from the group consisting of
ethanoyloxy,
propanoyloxy, butanoyloxy, pentanoyloxy, hexanoyloxy, heptanoyloxy,
octanoyloxy,
nonoyloxy, decanoyloxy, undecanoyloxy, dodecanoyloxy, tridecanoyloxy,
tetradecanoyloxy,
pentadecanoyloxy, hexadecanoyloxy, and octadecanoyloxy. Exemplary such
triesters include
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9,1 0-bis-hexanoyloxy-octadecanoic acid hexyl ester and 9,1 0-bis-decanoyloxy-
octadecanoic
acid decyl ester.
[040] In some embodiments, the ester base oil comprises a triester species
having
the following chemical structure (3):
0
R120 0
%
R9n 0R10 (3)
Rii 0
0
wherein R9, R10, R115 and R12 are independently selected from hydrocarbon
groups having
from 2 to 20 carbon atoms, and wherein "n" is an integer from 2 to 20.
[041] For the above-described triester species (3), R9 is typically selected
to have a
total carbon number of from 6 to 12, R" and R12 are typically selected to have
a combined
carbon number of from 2 to 40, R1 is typically selected to have a carbon
number of from 2 to
20, and "n" is typically an integer in the range of from 5 to 10. Depending on
the
embodiment, such resulting triester species (3) can have a molecular mass
between 400
a.m.u. and 1 100 a.m.u, or between 450 a.m.u. and 1000 a.m.u.
[042] In some embodiments, the triester species (3) is selected from the group
consisting of octadecane-1,9,10-triy1 trihexanoate; octadecane-1,9,10-triy1
triheptanoate;
octadecane-1,9,10-triy1 trioctanoate; octadecane-1,9,10-triy1 trinonoate;
octadecane-1,9,1 0-
triyl tris(decanoate); octadecane-1,9,10-triy1 tridodecanoate; octadecane-
1,9,10-triy1
triundecanoate; octadecane-1,9,10-triy1 tridodecanoate; octadecane 1,9,1 0-
triy1 tridecanoate;
and octadecane-1,9,10-triy1 tritetradecanoate; and mixtures thereof
[043] In some embodiments, the ester base oil is substantially homogeneous in
terms
of its triester species. In some other embodiments, the ester base oil
comprises a mixture of
triester species.
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Processes for Making the Triester
[044] Processes which can be employed in making the triesters are further
described
in U.S. Patent No. 7,544,645 and U.S. Patent Application Publication No.
2010/0311625.
[045] More specifically, in some embodiments, the process for making the
triester
species (2) comprises the following steps: (a) esterifying (i.e., subjecting
to esterification) a
mono-unsaturated fatty acid (or quantity of mono-unsaturated fatty acids)
having from 10 to
22 carbon atoms with an alcohol to form an unsaturated ester (or a quantity
thereof); (b)
epoxidizing the unsaturated ester to form an epoxy-ester species comprising an
epoxide ring;
(c) hydrolyzing the epoxide ring of the epoxy-ester species to form a
dihydroxy-ester species;
and (d) esterifying the dihydroxy-ester species with an esterifying agent
having from 2 to 18
carbon atoms to form the triester species, wherein the esterifying agent is
selected from the
group consisting of carboxylic acids, acyl halides, acid anhydrides, and
combinations thereof
[046] In some embodiments, the process for making the triester species (3) can
comprise reducing a mono-unsaturated fatty acid to form an unsaturated
alcohol. The
unsaturated alcohol is then epoxidized to form an epoxy-alcohol species
comprising an
epoxide ring. The epoxide ring of the epoxy-alcohol species is hydrolyzed to
form a triol; and
then the triol is esterified with an esterifying agent having from 2 to 18
carbon atoms to form
the triester species, wherein the esterifying agent is selected from the group
consisting of
carboxylic acids, acyl halides, acid anhydrides, and combinations thereof
[047] In other embodiments, the process for making the triester species (3)
can
comprise (a) reducing a mono-unsaturated fatty acid to form an unsaturated
alcohol; (b)
epoxidizing the unsaturated alcohol to form an epoxy-alcohol species
comprising an epoxide
ring; and (c) esterifying the epoxy-alcohol species with an esterifying agent
having from 2 to
18 carbon atoms to form the triester species, wherein the esterifying agent is
selected from
the group consisting of carboxylic acids, acyl halides, acid anhydrides, and
combinations
thereof
[048] In some embodiments, where a quantity of the triester species is formed,
the
quantity of triester species can be substantially homogeneous, or it can be a
mixture of two or
more different such triester species. Additionally or alternatively, in some
embodiments, such
processes further comprise a step of blending the triester species with one or
more diester
species.
[049] In some embodiments, the step of esterifying (i.e., esterification) the
mono-
unsaturated fatty acid can proceed via an acid-catalyzed reaction with an
alcohol using, e.g.,
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H2SO4 as a catalyst. In some or other embodiments, the esterifying can proceed
through a
conversion of the fatty acid(s) to an acyl halide (e.g., chloride, bromide, or
iodide) or acid
anhydride, followed by reaction with an alcohol. In some embodiments, the mono-
unsaturated fatty acid is a bio-derived fatty acid. In some such embodiments,
this involves the
extraction of some oil (e.g., triglyceride) component from the biomass and
hydrolysis of the
triglycerides of which the oil component is comprised so as to form free
carboxylic acids. In
some embodiments, the alcohol(s) is derived from a Fischer-Tropsch process.
[050] Regarding the step of reducing a mono-unsaturated fatty acid to the
corresponding unsaturated alcohol, lithium aluminum hydride can be used as the
reducing
agent in some embodiments. In other embodiments, particularly for industrial-
scale
processes, catalytic hydrogenation can be employed using, for example, copper-
or zinc-
based catalysts. See, e.g., U.S. Pat. No. 4,880,937; C. Scrimgeour, "Chemistry
of Fatty
Acids," in Bailey's Industrial Oil and Fat Products, Sixth Edition, Vol. 1, 1-
43, F. Shahidi
(Ed.), J. Wiley & Sons, New York, 2005.
[051] Regarding the step of epoxidizing (i.e., the epoxidation step), this
step is
generally consistent with that as previously described herein.
[052] Regarding the step of hydrolyzing the epoxide ring via acid- or base-
catalysis,
this step is generally consistent with that as previously described herein.
[053] Regarding the step of directly esterifying an epoxide, this step is
generally
consistent with that as previously described herein.
Additives
[054] The industrial oil comprises at least one additive. Additives can
include, for
example, pour point depressants, anti-wear agents, EP agents, detergents,
dispersants,
antioxidants, viscosity index improvers, friction modifiers, demulsifiers,
foam inhibitors,
corrosion inhibitors, rust inhibitors, seal swell agents, emulsifiers, wetting
agents, lubricity
improvers, metal deactivators, gelling agents, tackiness agents, bactericides,
fungicides,
thickeners, fluid-loss additives, colorants, and the like. In some
embodiments, the industrial
oil is substantially free of any viscosity index improver. As used herein, the
term
"substantially free" shall be understood to mean relatively little to no
amount of any viscosity
index improver, e.g., an amount less than about 0.5 wt. %, less than 0.25 wt.
%, or less than
0.1 wt. %, based on the total weight of the industrial oil composition.
[055] In some embodiments, the industrial oil has a viscosity index of at
least 140,
e.g., from 140 to 300; in some embodiments, at least 150. In some embodiments,
the
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industrial oil has a kinematic viscosity at 100 C of from 3 mm2/s to 25 mm2/s,
or from 4
mm2/s to 20 mm2/s.
EXAMPLES
[056] The following examples are given to illustrate the present invention. It
should
be understood, however, that the invention is not to be limited to the
specific conditions or
details described in these examples.
[057] As an exemplary synthetic procedure, the synthesis of a diester species
having
a vicinal diester substituent is described in Examples 1-2.
Example 1
Synthesis of C14 Diol Isomers
[058] In a 3-neck 3 L reaction flask equipped with an overhead stirrer and
placed in
an ice bath, 260 g of 30% hydrogen peroxide (2.3 mol) was added to 650 g of 88
wt. %
formic acid (12.4 mol). To this mixture, 392 g (2 mol) of a mixture of
tetradecene isomers
(i.e., a mixture of the following: 1-tetradecene, 2-tetradecene, 3-
tetradecene, 4-tetradecene, 5-
tetradecene, 6-tetradecene and 7-tetradecene) was added slowly over a 45-
minute period via
an addition funnel while ensuring that the reaction temperature stayed below
45 C. Once the
addition of the olefin was complete, the reaction was allowed to stir for 2
hours while cooling
in an ice bath to prevent a rise in the temperature above 40 C to 45 C. The
ice bath was then
removed and the reaction was stirred at room temperature overnight. The
reaction mixture
was concentrated with a rotary evaporator in a hot water bath at approximately
30 mm Hg
(Torr) to remove most of the water and formic acid. Then, 400 mL of an ice-
cold 1 M
solution of sodium hydroxide was added very slowly (i.e., in small portions)
to the remaining
residue of the reaction. Once all the sodium hydroxide solution was added, the
mixture was
allowed to stir for an additional 2 hours at about 80 C. The mixture was then
diluted with 500
mL of ethyl acetate and transferred to a separatory funnel. The organic layer
was separated
and the aqueous layer was extracted 3 times with ethyl acetate (300 mL each).
The ethyl
acetate extracts were all combined and dried over anhydrous MgSO4. Filtration,
followed by
concentration on a rotary evaporator at reduced pressure in a hot water bath
yielded a
tetradecene-diol mixture (diol isomers prepared from the tetradecene isomers)
as a waxy
substance in 96% yield (443 g). The tetradecene-diols were characterized by
infrared (IR),
nuclear magnetic resonance (NMR) spectroscopy and gas chromatography/mass
spectrometry
(GC/MS).
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Example 2
Synthesis of Diesters from C14 Diol Isomers and Lauric Acid
[059] In a 3-neck 1 L reaction flask equipped with an overhead stirrer, reflux
condenser, and a dropping funnel, 440 g (0.95 mol) of the tetradecene-diol
mixture (prepared
as described in Example 1), 1148 g (5.7 mol) of lauric acid, and 17.5 g of 85
wt. % H3PO4
(0.15 mol) were mixed. The resulting mixture was heated to 150 C and stirred
for several
hours while monitoring the progress of the reaction by NMR and GC/MS. After
stirring for 6
hours, the reaction was complete and the mixture cooled down to room
temperature. The
reaction mixture was washed with 1000 mL of water and the organic layer was
separated
using a separatory funnel. The organic layer was further rinsed with brine
solution (1000 mL
of saturated sodium chloride solution). The resulting mixture was then
distilled at 220 C and
100 mm Hg (Ton) to remove excess lauric acid. The diester product (the
remaining residue in
the distillation flask) was recovered as faint yellow oil in 84% yield (1000
g). The mixture of
diesters (diester product) was hydrogenated to remove any residual olefins
that could have
formed by elimination during the esterification reaction. The colorless oil so
obtained was
analyzed by IR, NMR and GC/MS.
[060] As an exemplary synthetic procedure, the synthesis of a triester species
having
a vicinal diester substituent is described in Examples 3-8. This procedure is
representative for
making triesters from mono-unsaturated carboxylic acids and alcohols, in
accordance with
some embodiments of the present invention.
Example 3
Synthesis of Oleoyl Chloride
[061] A three-neck 2-L round bottom reaction flask was fitted with a
mechanical
stirrer, reflux condenser and a water-filled trap to catch the evolving SO2
and HC1 gases. The
flask was charged with 500 mL of dichloromethane and 168 g (0.14 mol) of
thionyl chloride.
The reaction was cooled to 0 C and 200 g (0.71 mol) of oleic acid was added
drop-wise to
the reaction vessel via an addition funnel. Once all of the oleic acid was
added, the reaction
mixture was refluxed until the evolution of gases ceased. The reaction mixture
was cooled
and concentrated on a rotary evaporator under reduced pressure to remove the
solvent
(dichloromethane) and excess thionyl chloride. The reaction afforded the
oleoyl chloride as
viscous oil in about 98% yield (210 g). The product was confirmed by NMR, IR
and GC/MS.
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Example 4
Synthesis of Hexyl Oleate
[062] In a 3-neck 2-L reaction flask equipped with a mechanical stirrer,
dropping
funnel and a reflux condenser, 100 g (0.33 mol) of oleoyl chloride
(synthesized according to
the procedure described in Example 3) was added drop-wise to a solution of 51
g (0.5 mol) of
hexanol and 42 g (0.41 mol) of triethylamine at 0 C in 800 mL of anhydrous
hexanes. Once
the addition was complete, the reaction mixture was heated to reflux
overnight. The reaction
mixture was cooled down and neutralized with water. The two-layer solution was
transferred
to a separatory funnel, and the organic layer was separated and washed a few
times with
water. The aqueous layer was extracted with 500 mL of ether, and the ether
extract was added
to the organic layer and dried over MgSO4. Filtration and concentration at
reduced pressure
gave the hexyl oleate mixed with excess hexanol. The products were purified by
column
chromatography by eluting first with hexanes and then with 3% ethyl acetate in
hexane. The
product was isolated as pale yellow oil. The product identity was confirmed by
NMR, IR and
GC/MS. The reaction afforded a 93% yield (112 g) of hexyl oleate. Hexyl oleate
has the
following structure:
7
0
Example 5
Epoxidation of Hexyl Oleate
[063] A 1-L round bottom 3-neck reaction flask was equipped with a mechanical
stirrer, powder funnel, and a reflux condenser. The flask was charged with 500
mL of
dichloromethane and 110 g (0.3 mol) of hexyl oleate as prepared in Example 4.
The solution
was cooled to 0 C, and 1101 g of 77% m-chloroperoxybenzoic acid (0.45 mol
mCPBA) was
added in small portions over a period of about 30 minutes. Once all of the
mCPBA was
added, the reaction was allowed to stir for 48 hours at room temperature. The
resulting milky
reaction solution was filtered, and the filtrate was washed twice with the
slow addition of a
10% aqueous solution of sodium bicarbonate. The organic layer was washed
several times
with water, dried over anhydrous Mg504, and filtered. The filtrate was
evaporated to give a
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waxy looking substance. The product was confirmed by NMR, IR and GC/MS. The
reaction
yielded 93 g (81%) of product. The product has the following structure:
>A-.0
0
0
Example 6
Synthesis of 9,10-Dihydroxy-octadecanoic Acid Hexyl Ester
[064] In a 1-L reaction flask equipped with an overhead stirrer, 90 g (0.23
mol) of
the epoxy-ester prepared in Example 5 was suspended in 300 mL of a 3 wt. %
aqueous
solution of perchloric acid and 300 mL of hexane. The suspension was
vigorously stirred for
3 hours. The two-layer solution was separated and the aqueous layer was
extracted with 300
mL of ethyl acetate. The organic phases were combined and dried over MgSO4.
Filtration and
concentration at reduced pressure on a rotary evaporator produced a viscous
oil. Upon
standing at room temperature, the oil separated into an oily phase and a white
precipitate. The
solids were separated from the oil by filtration. IR and GC/MS analysis showed
the solid to
be the dihydroxy-ester species. The reaction afforded approximately 52% (47 g)
of the 9,10-
dihydroxy-octadecanoic acid hexyl ester. 9,10-Dihydroxy-octadecanoic acid
hexyl ester has
the following structure:
OH
0
.7
OH 0
Example 7
Synthesis of 9,10-Bis-hexanoyloxy-octadecanoic Acid Hexyl Ester
[065] In a 1-L 3-neck reaction flask equipped with an overhead stirrer, reflux
condenser, and a heating mantle, 45 g (0.11 mol) of the dihydroxy-ester (9,10-
dihydroxy-
octadecanoic acid hexyl ester, prepared according to the procedure of Example
6) and 33 g of
triethylamine (0.33 mol) were mixed in 250 mL of anhydrous hexanes. To this
mixture, 44 g
(0.33 mol) of hexanoyl chloride was added dropwise via an addition funnel over
a 30-minute
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period. Once the addition was completed, the reaction was refluxed for 48 h.
The resulting
milky solution was neutralized with water. The resulting two-phase solution
was separated by
means of a separatory funnel. The organic layer was washed extensively with
water and the
aqueous layer was extracted with 300 mL of ether. The organic layers were
combined and
dried over anhydrous MgSO4, filtered, and concentrated at reduced pressure.
GC/MS analysis
of the product indicated the presence of hexanoic acid. The product was then
washed with an
ice-cold sodium carbonate solution to remove the residual hexanoic acid. The
solution was
extracted with ethyl acetate which was dried over Na2SO4, filtered, and
concentrated to give
the final triester as a colorless oil in 83% yield (65 g). The product was
confirmed by NMR,
IR and GC/MS. 9,10-Bis-hexanoyloxy-octadecanoic acid hexyl ester has the
following
structure:
0
0
0
7
7
0 0
0
Example 8
Synthesis of 9,10-Bis-decanoyloxy-octadecanoic Acid Decyl Ester
[066] Decyl oleate was synthesized using the synthetic protocols described in
Examples 3 and 4. The 9,10-dihydroxy-ocatanoic acid decyl ester was
synthesized by
epoxidizing decyl oleate according to the epoxidation procedure described in
Example 5
followed by hydrolysis of the epoxide to form the corresponding diol using the
synthetic
procedure described in Example 6. The triester, 9,10-bis-decanoyloxy-
octadecanoic acid
decyl ester, was synthesized by reacting 9,10-dihydroxy-ocatanoic acid decyl
ester with
decanoyl chloride (decanoic acid chloride) according to the procedure
described in Example
7. 9,10-Bis-decanoyloxy-octadecanoic acid decyl ester has the following
structure:
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0
8
0
7
7
0
Example 9
[067] The diesters and triester species described herein are themselves
capable of
serving as lubricants. Referring to Table 1, the viscometric, low-temperature
and oxidation
stability properties are tabulated for three different diester mixtures having
been made in a
manner such as described in Example 2 (i.e., from an isomeric diol mixture),
the triesters of
Examples 7 and 8, and several naphthenic oils commonly employed in industrial
oils.
Table 1
VI KV40, KVioo, Pour Cloud Ox. BN,
mm2/s mm2/s Pt., ., C Pt C
h
Diesters from C14 diol isomers 109 16.3 3.6 ¨66 ¨69
19.5
and C6-C10 carboxylic acids
Diesters from C16 diol isomers 124 17.9 4 ¨51 ¨51
25.8
and C6-C10 carboxylic acids
Diesters from C16 diol isomers 152 24.4 5.2 ¨19 ¨18
38
and lauric acid
Triester of Example 7 139 13.9 3.5 ¨66 ¨48
Triester of Example 8 157 42.7 7.9 ¨29 ¨29
Mixture of Examples 7 and 8 159 25.1 5.4 ¨39 ¨38 8.1
(50/50 wt. %)
RAFFENE8 750L < 80 162.1 10.81 5
HYNAP N100HTS < 80 20.50 3.58 ¨30
Example 10
[068] Several saw guide oils were prepared and tested as set forth in Table 2.
Saw
Guide Oil 1 employed an ester base oil prepared as described in Example 2.
Storage stability
tests were used to observe the additive solvencies over a 3 week period at ¨25
C. The
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additive solvency observations were made at the test temperature, and again,
after warming,
at room temperature. A liquid rating of 1 indicated that the oil was clear. A
liquid rating of 5
indicated heavy cloud. A sediment rating of 1 indicated that the oil had
slight floc. The
storage stability was deemed excellent if no sediment was noted at the bottom
of the sample
bottle.
Table 2
Saw Guide Oil 1 Saw Guide Oil 2
Component, wt. %
Ester base oil 96.68 -
Naphthenic base oils 96.68
Additive package comprising
corrosion inhibitor,
emulsifier, tackifier, EP/anti- 3.32 3.32
wear agent and foam
inhibitor
Properties
Kinematic Viscosity 27.71 43.48
at 40 C, mm2/s
Kinematic Viscosity 5.653 5.744
at 100 C, mm2/s
Viscosity Index 150 56
Test
Initial Storage Stability 1/0 1/0
Rating, Liquid/Sediment
Storage Stability Rating
After 3 Weeks at ¨25 C 5/Frozen 5/Frozen
(read at ¨25 C),
Liquid/Sediment
Storage Stability Rating
Read After 3 Weeks at
¨25 C 5/0 6/1
(read at room temperature),
Liquid/Sediment
[069] From the foregoing results, it can be seen that the industrial oil
containing an
ester having a vicinal diester substituent exhibited much improved viscosity
index and
improved additive solubility. Even after storing of Saw Guide Oil 1 for three
weeks at ¨25 C,
no sediment or floc was observed.
[070] In summary, industrial oil formulations are provided which comprise an
ester
having a vicinal diester substituent, and wherein at least a portion of the
ester is bio-derived.
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Many such formulations of the present application are expected to favorably
compete with
similar, existing industrial oils comprising naphthenic base oils (e.g.,
hydraulic oils, rock drill
oils, saw guide oils, way oils). Such formulations are generally expected to
meet or exceed
such existing formulations in a number of areas including, but not limited to,
viscosity index,
additive solvency, biodegradability, and/or toxicity.
[071] 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." Accordingly, unless indicated to the contrary,
the numerical
parameters set forth in the following specification and attached claims are
approximations
that can vary depending upon the desired properties sought to be obtained. It
is noted that, as
used in this specification and the appended claims, the singular forms "a,"
"an," and "the,"
include plural references unless expressly and unequivocally limited to one
referent. As used
herein, the term "include" and its grammatical variants are intended to be non-
limiting, such
that recitation of items in a list is not to the exclusion of other like items
that can be
substituted or added to the listed items. As used herein, the term
"comprising" means
including elements or steps that are identified following that term, but any
such elements or
steps are not exhaustive, and an embodiment can include other elements or
steps.
[072] Unless otherwise specified, the recitation of a genus of elements,
materials or
other components, from which an individual component or mixture of components
can be
selected, is intended to include all possible sub-generic combinations of the
listed
components and mixtures thereof.
[073] 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. The
patentable scope is defined by the claims, and can include other examples that
occur to those
skilled in the art. Such other examples are intended to be within the scope of
the claims if
they have structural elements that do not differ from the literal language of
the claims, or if
they include equivalent structural elements with insubstantial differences
from the literal
languages of the claims. To an extent not inconsistent herewith, all citations
referred to herein
are hereby incorporated by reference.
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