U.S. patent application number 16/035056 was filed with the patent office on 2020-01-16 for limonene-derived diisocyanate compounds.
The applicant listed for this patent is International Business Machines Corporation. Invention is credited to SCOTT B. KING, BRANDON M. KOBILKA, JOSEPH KUCZYNSKI, JASON T. WERTZ.
Application Number | 20200017437 16/035056 |
Document ID | / |
Family ID | 69057656 |
Filed Date | 2020-01-16 |
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United States Patent
Application |
20200017437 |
Kind Code |
A1 |
KOBILKA; BRANDON M. ; et
al. |
January 16, 2020 |
LIMONENE-DERIVED DIISOCYANATE COMPOUNDS
Abstract
According to one aspect, a process of forming a diisocyanate
compound from limonene is disclosed. The process includes
performing an oxidation reaction to form a limonene-ketone from
limonene having a ketone group at a first position. The process
includes performing a conjugate addition reaction on the
limonene-ketone to form a limonene-nitrile having a nitrile group
bonded at a second position. The process also includes performing a
reductive amination reaction on the limonene-nitrile to form a
limonene-diamine by reducing the nitrile group to form a first
amine group and converting the ketone group to a second amine
group. The process further includes forming the diisocyanate
compound by converting the first amine group of the
limonene-diamine to a first isocyanate group and the second amine
group of the limonene-diamine to a second isocyanate group.
Inventors: |
KOBILKA; BRANDON M.;
(TUCSON, AZ) ; WERTZ; JASON T.; (PLEASANT VALLEY,
NY) ; KUCZYNSKI; JOSEPH; (NORTH PORT, FL) ;
KING; SCOTT B.; (ROCHESTER, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
International Business Machines Corporation |
ARMONK |
NY |
US |
|
|
Family ID: |
69057656 |
Appl. No.: |
16/035056 |
Filed: |
July 13, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C 209/16 20130101;
C07C 2601/14 20170501; C07C 253/10 20130101; C07C 29/03 20130101;
C07C 209/48 20130101; C07C 265/14 20130101; C07C 263/10 20130101;
C07C 253/10 20130101; C07C 255/46 20130101; C07C 209/48 20130101;
C07C 211/36 20130101; C07C 263/10 20130101; C07C 265/14 20130101;
C07C 29/03 20130101; C07C 33/14 20130101 |
International
Class: |
C07C 265/14 20060101
C07C265/14; C07C 263/10 20060101 C07C263/10 |
Claims
1. A process of forming a diisocyanate compound from limonene, the
process comprising: performing an oxidation reaction to form a
limonene-ketone from limonene, the limonene-ketone having a ketone
group at a first position; performing a conjugate addition reaction
on the limonene-ketone to form a limonene-nitrile having a nitrile
group bonded at a second position; performing a reductive amination
reaction on the limonene-nitrile to form a limonene-diamine by
reducing the nitrile group to form a first amine group and
converting the ketone group to a second amine group; and forming a
diisocyanate compound by converting the first amine group of the
limonene-diamine to a first isocyanate group and the second amine
group of the limonene-diamine to a second isocyanate group.
2. The process of claim 1, wherein the limonene-diamine has the
formula ##STR00021##
3. The process of claim 2, wherein the diisocyanate compound has
the formula ##STR00022##
4. The process of claim 1, wherein the limonene-diamine has the
formula ##STR00023##
5. The process of claim 4, wherein the diisocyanate compound has
the formula ##STR00024##
6. The process of claim 1, wherein the oxidation reaction
corresponds to a direct oxidation reaction, and wherein the
limonene-nitrile has the formula ##STR00025##
7. The process of claim 1, wherein the first amine group is
converted to the first isocyanate group and the second amine group
is converted to the second isocyanate group via a phosgenation
reaction.
8. A process of forming a diisocyanate compound from limonene, the
process comprising: converting limonene to a limonene-diol having a
first hydroxyl group and a second hydroxyl group, wherein the
limonene-diol has a formula selected from the group consisting of:
##STR00026## performing a catalytic amination reaction on the
limonene-diol to form a limonene-diamine by converting the first
hydroxyl group to a first amine group and the second hydroxyl group
to a second amine group; and forming a diisocyanate compound by
converting the first amine group of the limonene-diamine to a first
isocyanate group and the second amine group of the limonene-diamine
to a second isocyanate group.
9. The process of claim 8, wherein the limonene-diamine has the
formula ##STR00027##
10. The process of claim 9, wherein the diisocyanate compound has
the formula ##STR00028##
11. (canceled)
12. The process of claim 8, wherein the limonene-diamine has the
formula ##STR00029##
13. The process of claim 12, wherein the diisocyanate compound has
the formula ##STR00030##
14. The process of claim 8, wherein converting limonene to the
limonene-diol includes: forming a limonene-alcohol from limonene,
the limonene-alcohol having the first hydroxyl group; and forming
the limonene-diol from the limonene-alcohol.
15. (canceled)
16. A limonene-derived diisocyanate compound having a formula
selected from the group consisting of: ##STR00031##
17. The limonene-derived diisocyanate compound of claim 16, formed
from a limonene-derived diamine having the formula ##STR00032##
18. The limonene-derived diisocyanate compound of claim 16, formed
from a limonene-derived diamine having the formula ##STR00033##
19. The limonene-derived diisocyanate compound of claim 16, formed
from a limonene-derived diamine having the formula ##STR00034##
20. The limonene-derived diisocyanate compound of claim 16, formed
from a limonene-derived diamine having the formula ##STR00035##
Description
BACKGROUND
[0001] Isophorone diisocyanate (IPDI) is an example of an aliphatic
diisocyanate that may be used in specialized applications, such as
polyurethane coatings which are resistant to abrasion and
degradation from ultraviolet light. IPDI may be synthesized from
renewable sources, such as sugars. For example, bacterial
fermentation of sugar may be used to form acetone, which may then
be utilized to synthesize IPDI. Alternative diisocyanates that are
derived from bio-renewable resources may also provide benefits in a
variety of applications.
SUMMARY
[0002] According to an embodiment, a process of forming a
diisocyanate compound from limonene is disclosed. The process
includes performing an oxidation reaction to form a limonene-ketone
from limonene having a ketone group at a first position. The
process includes performing a conjugate addition reaction on the
limonene-ketone to form a limonene-nitrile having a nitrile group
bonded at a second position. The process also includes performing a
reductive amination reaction on the limonene-nitrile to form a
limonene-diamine by reducing the nitrile group to form a first
amine group and converting the ketone group to a second amine
group. The process further includes forming a diisocyanate compound
by converting the first amine group of the limonene-diamine to a
first isocyanate group and the second amine group of the
limonene-diamine to a second isocyanate group.
[0003] According to another embodiment, a process of forming a
diisocyanate compound from limonene is disclosed. The process
includes converting limonene to a limonene-diol having a first
hydroxyl group and a second hydroxyl group. The process also
includes performing a catalytic amination reaction on the
limonene-diol to form a limonene-diamine by converting the first
hydroxyl group to a first amine group and the second hydroxyl group
to a second amine group. The process further includes forming a
diisocyanate compound by converting the first amine group of the
limonene-diamine to a first isocyanate group and the second amine
group of the limonene-diamine to a second isocyanate group.
[0004] According to yet another embodiment, a limonene-derived
diisocyanate compound is disclosed. In a first case, the
limonene-derived diisocyanate compound may have the formula:
##STR00001##
[0005] In a second case, the limonene-derived diisocyanate compound
may have the formula:
##STR00002##
[0006] In a third case, the limonene-derived diisocyanate compound
may have the formula:
##STR00003##
[0007] In a fourth case, the limonene-derived diisocyanate compound
may have the formula:
##STR00004##
[0008] The foregoing and other objects, features, and advantages of
the invention will be apparent from the following more particular
descriptions of exemplary embodiments of the invention as
illustrated in the accompanying drawings wherein like reference
numbers generally represent like parts of exemplary embodiments of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a diagram depicting four examples of diisocyanate
compounds formed from limonene, according to the present
disclosure.
[0010] FIGS. 2A and 2B are chemical reaction diagrams depicting a
first example of a process of forming a limonene-derived
diisocyanate compound, according to one embodiment of the present
disclosure.
[0011] FIGS. 3A to 3C are chemical reaction diagrams depicting a
second example of a process of forming a limonene-derived
diisocyanate compound, according to one embodiment of the present
disclosure.
[0012] FIGS. 4A and 4B are chemical reaction diagrams depicting a
third example of a process of forming a limonene-derived
diisocyanate compound, according to one embodiment of the present
disclosure.
[0013] FIGS. 5A and 5B are chemical reaction diagrams depicting a
fourth example of a process of forming a limonene-derived
diisocyanate compound, according to one embodiment of the present
disclosure.
[0014] FIG. 6 is a flow diagram illustrating a particular
embodiment of a process of utilizing one or more of the
limonene-derived diisocyanate compounds of the present disclosure
to form a polyurethane (PU) material.
DETAILED DESCRIPTION
[0015] The present disclosure describes diisocyanate compounds and
processes for forming the diisocyanate compounds from limonene.
Among other possible uses, one or more of the limonene-derived
diisocyanates of the present disclosure may be reacted with one or
more polyols to form various polyurethane (PU) materials. Various
intermediate materials described herein that are formed during the
synthesis of the diisocyanate compounds may represent novel
compositions of matter, such as one or more of the diamine
precursors to the diisocyanate compounds. Thus, while the present
disclosure describes one possible use of the final diisocyanate
compounds for the formation of polyurethanes, it will be
appreciated that diisocyanate compounds and/or the intermediate
materials may be utilized in alternative contexts.
[0016] FIG. 1 is a diagram 100 depicting four examples of
diisocyanate compounds derived from limonene (IUPAC name
1-Methyl-4-(prop-1-en-2-yl)cyclohex-1-ene), according to various
embodiments of the present disclosure. References to "positions"
herein correspond to the IUPAC name. To illustrate, position 1
corresponds to the first carbon (C1) in the cyclohexene ring that
is bonded to the Methyl group, and position 2 corresponds to the
carbon (C2) in the cyclohexene ring that is double-bonded to the
first carbon (C1).
[0017] The first limonene diisocyanate depicted in FIG. 1 (also
referred to herein as "LDI-1") corresponds to a compound having the
formula:
##STR00005##
[0018] The first limonene diisocyanate may be formed according to
the processes illustrated and further described herein with respect
to FIGS. 2A and 2B. The first limonene diisocyanate represents a
first example of a diisocyanate that may be formed according to a
process where limonene is oxidized, followed by a conjugate
addition reaction, a reductive amination reaction, and subsequent
conversion of amine groups to isocyanate groups. The first limonene
diisocyanate represents a first example of an aliphatic
diisocyanate that is structurally analogous to IPDI. Thus, in some
cases, the first limonene diisocyanate may be used in similar
specialized applications in which IPDI is utilized, such as
polyurethane coatings which are resistant to abrasion and
degradation from ultraviolet light.
[0019] The second limonene diisocyanate depicted in FIG. 1 (also
referred to herein as "LDI-2") corresponds to a compound having the
formula:
##STR00006##
[0020] The second limonene diisocyanate may be formed according to
the processes illustrated and further described herein with respect
to FIGS. 3A to 3C. The second limonene diisocyanate represents a
second example of a diisocyanate that may be formed according to a
process where limonene is oxidized, followed by a conjugate
addition reaction, a reductive amination reaction, and subsequent
conversion of amine groups to isocyanate groups. The second
limonene diisocyanate represents a second example of an aliphatic
diisocyanate that is structurally analogous to IPDI. Thus, in some
cases, the second limonene diisocyanate may be used in similar
specialized applications in which IPDI is utilized, such as
polyurethane coatings which are resistant to abrasion and
degradation from ultraviolet light.
[0021] The third limonene diisocyanate depicted in FIG. 1 (also
referred to herein as "LDI-3") corresponds to a compound having the
formula:
##STR00007##
[0022] The third limonene diisocyanate may be formed according to
the processes illustrated and further described herein with respect
to FIGS. 4A and 4B. The third limonene diisocyanate represents a
second example of a diisocyanate that may be formed according to a
process where limonene is converted to a diol, followed by a
catalytic amination reaction to convert the diol to a diamine, and
subsequent conversion of amine groups to isocyanate groups. The
third limonene diisocyanate represents a third example of an
aliphatic diisocyanate that is structurally analogous to IPDI.
Thus, in some cases, the third limonene diisocyanate may be used in
similar specialized applications in which IPDI is utilized, such as
polyurethane coatings which are resistant to abrasion and
degradation from ultraviolet light.
[0023] The fourth limonene diisocyanate depicted in FIG. 1 (also
referred to herein as "LDI-4") corresponds to a compound having the
formula:
##STR00008##
[0024] The fourth limonene diisocyanate may be formed according to
the processes illustrated and further described herein with respect
to FIGS. 5A and 5B. The fourth limonene diisocyanate represents a
second example of a diisocyanate that may be formed according to a
process where limonene is converted to a diol, followed by a
catalytic amination reaction to convert the diol to a diamine, and
subsequent conversion of amine groups to isocyanate groups. The
fourth limonene diisocyanate represents a fourth example of an
aliphatic diisocyanate that is structurally analogous to IPDI.
Thus, in some cases, the fourth limonene diisocyanate may be used
in similar specialized applications in which IPDI is utilized, such
as polyurethane coatings which are resistant to abrasion and
degradation from ultraviolet light.
[0025] FIGS. 2A-2B and 3A-3C illustrate processes for forming
diisocyanates from limonene via similar synthetic pathways. In both
cases, limonene is oxidized, followed by a conjugate addition
reaction, a reductive amination reaction, and subsequent conversion
of amine groups to isocyanate groups. FIGS. 2A-2B and 3A-3C
illustrate that, depending on oxidation conditions, limonene is
oxidized to form a ketone group in either of two positions.
Depending on the oxidation position, the conjugate addition
reaction yields a nitrile group in either of two positions. The
reductive amination reaction yields one diamine for one combination
of ketone and nitrile group positions and yields a different
diamine for the other combination of ketone and nitrile group
positions. Conversion of the amine groups of the different diamines
to isocyanate groups yields different diisocyanate compounds.
[0026] FIGS. 2A and 2B are chemical reactions diagrams 200, 210
depicting a first example of a process of forming a
limonene-derived diisocyanate compound, according to one embodiment
of the present disclosure. The process depicted in FIGS. 2A-2B may
be utilized to form the first limonene diisocyanate (LDI-1)
depicted in FIG. 1.
[0027] The first chemical reaction depicted in FIG. 2A illustrates
the oxidation of limonene at a first position. The oxidation
results in a limonene-ketone having a ketone group at a first
oxidation position. The first oxidation position corresponds to
position 6 (C6), with the resulting limonene-ketone having the
formula:
##STR00009##
[0028] EXAMPLE: About 10 mmol of 30% hydrogen peroxide may be added
to a mixture of limonene (5 mmol) plus catalyst (polymer-anchored
iron(III)-ferrocene Schiff base complex, 0.05 g) in 10 mL of a
polar aprotic organic solvent such acetonitrile, dimethylsulfoxide
(DMSO), etc. The polymer-anchored iron(III)-ferrocene Schiff base
complex may be synthesized according to the procedure outlined in
"Catalytic activity of an iron(III) Schiff base complex bound in a
polymer resin" by Islam et al., as published in Transition Met Chem
(2013), the contents of which are incorporated herein by reference
in its entirety. The reaction may be heated to 60.degree. C. and
stirred for 8 hours. The reaction mixture may be filtered and
washed with additional solvent, and the filtrate may be
concentrated. The crude product may then be purified by techniques
known to those skilled in the art, such as distillation and column
chromatography.
[0029] In the second chemical reaction depicted in FIG. 2A,
conjugate (Michael) addition to the double bond of the
limonene-ketone using potassium cyanate under acidic conditions
results in formation of a limonene-nitrile having a nitrile group
bonded at a second position. One of ordinary skill in the art will
appreciate that other reaction conditions may be used, including
those that do not require cyanide or hydrogen cyanide gas. The
second position corresponds to position 2 (C2), with the resulting
limonene-nitrile having the formula:
##STR00010##
[0030] EXAMPLE: To a solution of triethylamine hydrochloride (2
equiv.) in a mixture of methanol/water (1:1) may be added potassium
cyanide (2 equiv.) at room temperature. Limonene oxide (1 equiv.)
may be added to the reaction mixture over the course of one hour.
The reaction may then be stirred overnight until completion. The pH
may be adjusted to 6.5 using either dilute HCl (aq) or KOH(aq), and
the product may be isolated immediately via extraction (3.times.)
with diethyl ether to avoid cyanohydrin formation. The combined
organic extracts may be rinsed by water and brine and dried over
MgSO.sub.4. The solvents may be removed in vacuo, and the crude
product may be purified by distillation or column
chromatography.
[0031] In the third chemical reaction depicted in FIG. 2A, a
reductive amination is performed on the limonene-nitrile to form a
limonene-diamine. The reductive amination simultaneously reduces
the nitrile group to form a first amine group and converts the
ketone group to a second amine group. The resulting
limonene-diamine has the formula:
##STR00011##
[0032] EXAMPLE: An apparatus for converting the limonene-nitrile
into the limonene-diamine may consist of 5 reaction vessels. The
imination process may be carried out in the first two reaction
vessels. Reaction vessels three, four, and/or five may be used to
convert the imination process product into the diamine via a
reductive amination process. The first two reaction vessels may be
loaded with .gamma.-aluminum oxide. The temperature in the first
and second reaction vessels may be 70.degree. C. in each case. The
limonene-nitrile and 3.4 equivalents of ammonia per hour are fed
into the first reaction vessel. Additionally, 45 normal liters of
hydrogen per hour are fed at a pressure of 230 bar. The reductive
amination process is carried out in the 3rd and 4th reaction
vessels filled with a hydrogenation catalyst (for example 0.5 wt %
of Ru on a .gamma.-aluminum oxide support). The 5th reaction vessel
may be filled with a reduced Co catalyst (composition:
Mn.sub.3O.sub.4: 5-6.2 wt %, Na.sub.2O: 0-0.5 wt %,
H.sub.3PO.sub.4: 2.8-3.8 wt %, balance Co+CoO). The temperature in
the 3rd reaction vessel may be 70.degree. C. (first substage of
stage I of the reductive amination). The temperature in the 4th
reaction vessel may be 80.degree. C. (second substage of stage I of
the reductive amination). In the 5th reaction vessel, the
temperature may be 120.degree. C. (stage II of the reductive
amination). The reaction product of the imination may be introduced
into the inlet of the 3rd reaction vessel (first substage of stage
I). The reaction product after 91 hours may contain ammonia and
water, additionally. The apparatus consisted of a fixed bed
reactor, filled with 50 mL of ion exchanger according to EP 042 119
to catalyze the imine formation from IPN and ammonia, and a
downstream fixed-bed reactor, filled with 50 mL of the
hydrogenation catalyst. To improve the uniformity of liquid
distribution in the hydrogenation reactor, the catalyst bed of
silicon carbide with grain size <300 .mu.m is diluted. To
condition the catalyst, 100 mL/h (60 g/h) ammonia at 100.degree. C.
is passed over the fixed bed, with adjustment to a hydrogen partial
pressure of 100 bar during conditioning. Immediately following
twelve hours of conditioning, a solution of 14.2 wt % in IPN
ammonia was fed at 135 mL/h. The imination flows from bottom to top
(upflow), and the hydrogenation reactor flows from top to bottom
(downflow). Imination was set at a temperature of 50.degree. C. and
the hydrogenation at a temperature of 100.degree. C. Through a
control valve was held by the supply of hydrogen pressure in the
hydrogenation reactor at 250 bar constant.
[0033] While the present disclosure describes one possible use of
the above diamine form a diisocyanate for the formation of
polyurethanes, it will be appreciated that the diamine may
represent a novel composition of matter that may be utilized in
alternative contexts.
[0034] The chemical reaction diagram 210 of FIG. 2B illustrates
that the limonene-diamine of FIG. 2A may be reacted with phosgene
(COCL.sub.2) to give the LDI-1 compound depicted in FIG. 1.
[0035] Thus, FIGS. 2A and 2B illustrate an example of a process of
utilizing limonene to form a diisocyanate compound, corresponding
to the first limonene diisocyanate compound (LDI-1) depicted in
FIG. 1. In FIG. 2A, a first set of oxidation conditions results in
oxidation at a first oxidation position (C6), with the subsequent
conjugate addition reaction yielding a nitrile group at a first
nitrile group position (C2). Reductive amination yields a first
diamine, with FIG. 2B illustrating subsequent conversion of the
amine groups to isocyanate groups to form LDI-1. By contrast, FIG.
3A illustrates that a second set of oxidation conditions results in
oxidation at a second oxidation position (C3), with the subsequent
conjugate addition reaction yielding a nitrile group at a second
nitrile group position (C1). FIG. 3B illustrates that reductive
amination yields a second diamine, and FIG. 3C illustrates
subsequent conversion of the amine groups to isocyanate groups to
form a different diisocyanate compound, corresponding to the second
limonene diisocyanate compound (LDI-2) depicted in FIG. 1.
[0036] FIGS. 3A, 3B, and 3C are chemical reactions diagrams 300,
310, 320 depicting a second example of a process of forming a
limonene-derived diisocyanate compound, according to one embodiment
of the present disclosure. The process depicted in FIGS. 3A-3C may
be utilized to form the second limonene diisocyanate (LDI-2)
depicted in FIG. 1.
[0037] The first chemical reaction depicted in FIG. 3A illustrates
the direct oxidation of limonene, resulting in a limonene-ketone
having a ketone group at a second oxidation position. In contrast
to the first oxidation position in FIG. 2A, the second oxidation
position corresponds to position 3 (C3), with the resulting
limonene-ketone having the formula:
##STR00012##
[0038] EXAMPLE: To t-butyl alcohol may be added chromium trioxide
(4.0 equiv.) in small portions, and the mixture may be stirred for
15 minutes. The mixture may be extracted with CCl.sub.4, and the
combined organic layers may be dried over sodium sulfate and
concentrated to half of the volume. Limonene (1.0 equiv.) may be
added to this, and the resulting solution may be refluxed for 2
hours. Then the reaction mixture may be cooled to room temperature,
filtered, and the resulting crude residue may be purified on silica
gel column using EtOAc-hexane (1:9) as eluent.
[0039] In the second chemical reaction depicted in FIG. 3A,
conjugate addition to the double bond of the limonene-ketone
results in formation of a limonene-nitrile having a nitrile group
bonded at a second position. The conjugate addition reaction may be
performed in a similar manner to the process previously described
with respect to the conjugate addition reaction of FIG. 2A. The
second position corresponds to position 1 (C1), with the resulting
limonene-nitrile having the formula:
##STR00013##
[0040] While the present disclosure describes one possible use of
the above carbonitrile form a diisocyanate for the formation of
polyurethanes, it will be appreciated that the carbonitrile may
represent a novel composition of matter that may be utilized in
alternative contexts.
[0041] The chemical reaction diagram 310 of FIG. 3B illustrates
that a reductive amination is then performed on the
limonene-nitrile of FIG. 3A. The reductive amination reaction may
be performed in a similar manner to the process previously
described with respect to the reductive amination reaction of FIG.
2A. The reductive amination reaction simultaneously reduces the
nitrile group to form a first amine group and converts the ketone
group to a second amine group. The resulting limonene-diamine has
the formula:
##STR00014##
[0042] While the present disclosure describes one possible use of
the above diamine form a diisocyanate for the formation of
polyurethanes, it will be appreciated that the diamine may
represent a novel composition of matter that may be utilized in
alternative contexts.
[0043] The chemical reaction diagram 320 of FIG. 3C illustrates
that the limonene-diamine of FIG. 3B may be reacted with phosgene,
yielding the LDI-2 compound depicted in FIG. 1.
[0044] Thus, FIGS. 3A to 3C illustrate a second example of a
process of utilizing limonene to form a diisocyanate compound,
corresponding to the second limonene diisocyanate compound (LDI-2)
depicted in FIG. 1. The processes of FIGS. 2A-2B and 3A-3C
illustrate that alternative oxidation conditions result in
oxidation at different oxidation positions on the limonene
molecule. Subsequent conjugate addition and reductive amination
reactions on the oxidized limonene compounds yield different
diamines, and subsequent conversion of the amine groups yield
different diisocyanate compounds.
[0045] FIGS. 4A-4B and 5A-5B illustrate processes for forming
diisocyanate compounds from limonene via similar synthetic
pathways. In both cases, limonene is converted to a diol, followed
by a catalytic amination reaction to convert the diol to a diamine,
and subsequent conversion of amine groups to isocyanate groups.
FIGS. 4A-4B and 5A-5B illustrate that different diols may be
derived from limonene, with the catalytic amination reaction
yielding one diamine for one diol and a different diamine for the
other diol. Conversion of the amine groups of the different
diamines to isocyanate groups yields different diisocyanate
compounds.
[0046] FIGS. 4A and 4B are chemical reactions diagrams 400, 410
depicting a third example of a process of forming a
limonene-derived diisocyanate compound, according to one embodiment
of the present disclosure. The process depicted in FIGS. 4A-4B may
be utilized to form the third limonene diisocyanate (LDI-3)
depicted in FIG. 1.
[0047] The first chemical reaction depicted in FIG. 4A illustrates
hydroboration of limonene to form a limonene-diol having the
formula:
##STR00015##
[0048] EXAMPLE: Limonene (2M solution in THF, 1.0 equiv.) may be
added to BH.sub.3-THF solution (1M, 1.2 equiv.) at 0 to -25.degree.
C., and the mixture may be stirred at 0.degree. C. for two hours.
The reaction mixture may be quenched by the slow addition of 2.0 M
aq. NaOH (2 equiv.) and 35% aq. H.sub.2O.sub.2 (1.2 mL/equiv.). The
biphasic mixture may be stirred vigorously at 0.degree. C. for 1 h.
The biphasic mixture may be poured into water and extracted with
Et.sub.2O (3.times.), and the combined organic layer may be washed
with sat. aq. Na.sub.2S.sub.2O.sub.3 (1.times.) and brine (30 mL),
and then dried (MgSO.sub.4), filtered and concentrated. The residue
may be purified by flash column chromatography.
[0049] In the second chemical reaction depicted in FIG. 4A, the
limonene-diol is converted to a limonene-diamine via catalytic
amination in the presence of ammonia. The catalyst may include
nickel or ligated forms of ruthenium, palladium, rhodium, or
iridium and may be performed at elevated pressure and/or
temperature. The resulting limonene-diamine has the formula:
##STR00016##
[0050] EXAMPLE: A ligand such as Xanthphos, metal salt such as
[RuHCl(CO)(PPh.sub.3).sub.3], solvent such as toluene, and the
limonene-diol may be placed under an Ar atmosphere in a Parr
autoclave having a magnetically coupled inclined blade stirrer
(stirring speed: 200-500 revolutions/minute). In some cases, t-amyl
alcohol may be added to the mixture. An excess of ammonia may be
introduced at room temperature either in pre-condensed form or
directly from a pressurized NH.sub.3 gas bottle. The steel
autoclave may be electrically heated to a temperature up to
170.degree. C. and heated for up to 20 hours while stirring. The
autoclave may be cooled to room temperature, and the ammonia may be
outgassed at atmospheric pressure. The solvents may be removed in
vacuo and the product purified by fractional distillation.
[0051] While the present disclosure describes one possible use of
the above diamine form a diisocyanate for the formation of
polyurethanes, it will be appreciated that the diamine may
represent a novel composition of matter that may be utilized in
alternative contexts.
[0052] The chemical reaction diagram 410 of FIG. 4B illustrates
that the limonene-diamine of FIG. 4A is then reacted with phosgene,
yielding the LDI-3 compound depicted in FIG. 1.
[0053] Thus, FIGS. 4A and 4B illustrate an example of a process of
utilizing limonene to form a diisocyanate compound, corresponding
to the third limonene diisocyanate compound (LDI-3) depicted in
FIG. 1. In FIG. 4A, hydroboration yields two hydroxyl groups at
locations corresponding to the two isoprene units of limonene. By
contrast, FIG. 5A illustrates a biosynthesis reaction that forms a
modified limonene molecule having one hydroxyl group, with both
isoprene units intact. Subsequently, a selective hydroboration
reaction yields another hydroxyl group at a location corresponding
to one of the isoprene units. The different diols of FIGS. 4A and
5A yield different diamines, which are subsequently converted to
different diisocyanates (as shown in FIGS. 4B and 5B).
[0054] FIGS. 5A and 5B are chemical reactions diagrams 500, 510
depicting a fourth example of a process of forming a
limonene-derived diisocyanate compound, according to one embodiment
of the present disclosure. The process depicted in FIGS. 5A-5B may
be utilized to form the fourth limonene diisocyanate (LDI-4)
depicted in FIG. 1.
[0055] The first chemical reaction depicted in FIG. 5A illustrates
biosynthesis of a limonene-alcohol having one hydroxyl group by
Rhodococcus bacteria, with both isoprene units intact. The
limonene-alcohol has the formula:
##STR00017##
[0056] EXAMPLE: A biosynthesis environment may include cells/petri
dishes comprising either XN-1900 Rhodococcus sp. ALK2-E1,
Rhodococcus sp. HXN-1900, or Mycobacterium sp. HXN-1500
(respectively chosen for either D-limonene, L-limonene, or a
mixture of limonene isomers) grown on an agar mineral medium.
Alkane vapor may be cycled through the environment for 5 days, and
the resulting cell mass may be removed via scraping form the agar
surface. The residue may be washed and concentrated. This
suspension may be incubated in square deepwell microtiter plates
with either D-limonene and L-limonene and monitored for alcohol
formation. This may be removed via extraction with methanol, washed
with water, rinsed with brine, and dried over MgSO.sub.4. The
solvents may be removed in vacuo and the product purified by
fractional distillation or column chromatography.
[0057] In the second chemical reaction depicted in FIG. 5A,
selective hydroboration of the least-substituted alkene of the
limonene-alcohol yields a limonene-diol. An alternative to
hydroboration may be a hindered borane, such as 9-BBN or
disamylborane, with careful stoichiometric control. The resulting
limonene-diol has the formula:
##STR00018##
[0058] EXAMPLE: The limonene-alcohol (2M solution in THF, 1.0
equiv.) may be added to BH.sub.3-THF solution (1M, 1.2 equiv.) at 0
to -25.degree. C., and the mixture may be stirred at 0.degree. C.
for two hours. The reaction mixture may be quenched by the slow
addition of 2.0 M aq. NaOH (2 equiv.) and 35% aq. H.sub.2O.sub.2
(1.2 mL/equiv.). The biphasic mixture may be stirred vigorously at
0.degree. C. for 1 h. The biphasic mixture may be poured into water
and extracted with Et.sub.2O (3.times.), and the combined organic
layer may be washed with sat. aq. Na.sub.2S.sub.2O.sub.3 (1.times.)
and brine (30 mL), and then dried (MgSO.sub.4), filtered and
concentrated. The residue may be purified by flash column
chromatography.
[0059] In the third reaction depicted in FIG. 5A, the limonene-diol
is converted to a limonene-diamine via catalytic amination in a
similar manner to the process previously described with respect to
the catalytic amination reaction of FIG. 4A. The resulting
limonene-diamine has the formula:
##STR00019##
[0060] While the present disclosure describes one possible use of
the above diamine form a diisocyanate for the formation of
polyurethanes, it will be appreciated that the diamine may
represent a novel composition of matter that may be utilized in
alternative contexts.
[0061] The chemical reaction diagram 510 of FIG. 5B illustrates
that the limonene-diamine of FIG. 5A is then reacted with phosgene,
yielding the LDI-4 compound having the formula:
##STR00020##
[0062] Referring to FIG. 6, a flow diagram illustrates a particular
embodiment of a process 600 of forming a polyurethane (PU) material
from one or more of the limonene-derived diisocyanate compounds of
the present disclosure. It will be appreciated that the operations
shown in FIG. 6 are for illustrative purposes only and that the
operations may be performed by a single entity or by multiple
entities. As an example, one entity may form the limonene
diisocyanate compound(s) depicted in FIG. 1, while another entity
may form one or more polyols for polymerization with the
diisocyanate compound(s). Further, the same entity or a different
entity may polymerize the diisocyanate compound(s) and the
polyol(s) to form the PU material.
[0063] The process 600 includes forming one or more diisocyanate
compounds from limonene, at 602. For example, the first
diisocyanate compound (LDI-1) depicted in FIG. 1 may be formed from
limonene according to the process described herein with respect to
FIGS. 2A-2B. As another example, the second diisocyanate compound
(LDI-2) depicted in FIG. 1 may be formed from limonene according to
the process described herein with respect to FIGS. 3A-3C. As a
further example, the third diisocyanate compound (LDI-3) depicted
in FIG. 1 may be formed from limonene according to the process
described herein with respect to FIGS. 4A-4B. As yet another
example, the fourth diisocyanate compound (LDI-4) depicted in FIG.
1 may be formed from limonene according to the process described
herein with respect to FIGS. 5A-5B.
[0064] The process 600 includes forming a mixture that includes the
limonene-derived diisocyanate compound(s) and one or more polyols,
at 604. In some cases, a single limonene-derived diisocyanate
compound of the present disclosure (i.e., LDI-1, LDI-2, LDI-3, or
LDI-4) may be utilized. In other cases, a combination of
limonene-derived diisocyanate compounds of the present disclosure
may be utilized. In either case, the limonene-derived diisocyanate
compound(s) may be mixed with a single polyol or multiple polyols.
As illustrative, non-limiting examples, the polyol(s) may
correspond to ethylene glycol, propylene glycol, or a combination
thereof (among numerous other alternatives).
[0065] The process 600 includes initiating a polymerization
reaction to form a PU material from the mixture, at 606. The
limonene diisocyanates of the present disclosure are aliphatic
diisocyanates that are structurally analogous to IPDI. Thus, in
some cases, the PU material may be used in similar specialized
applications in which IPDI is utilized, such as polyurethane
coatings which are resistant to abrasion and degradation from
ultraviolet light.
[0066] It will be understood from the foregoing description that
modifications and changes may be made in various embodiments of the
present invention without departing from its true spirit. The
descriptions in this specification are for purposes of illustration
only and are not to be construed in a limiting sense. The scope of
the present invention is limited only by the language of the
following claims.
* * * * *