U.S. patent application number 15/097731 was filed with the patent office on 2016-08-11 for processes for making cyclohexane compounds.
This patent application is currently assigned to Eastman Chemical Company. The applicant listed for this patent is Eastman Chemical Company. Invention is credited to Scott Donald Barnicki, Venkata Bharat Ram Boppana, Robert Thomas Hembre.
Application Number | 20160229784 15/097731 |
Document ID | / |
Family ID | 52350327 |
Filed Date | 2016-08-11 |
United States Patent
Application |
20160229784 |
Kind Code |
A1 |
Hembre; Robert Thomas ; et
al. |
August 11, 2016 |
PROCESSES FOR MAKING CYCLOHEXANE COMPOUNDS
Abstract
This invention relates to hydrogenation processes for making
cyclohexane compounds. More specifically, this invention relates to
hydrogenation processes in the presence of tertiary amide solvent
compounds, as well as compositions that can result from such
processes. The invention thus provides processes for making
cyclohexanecarboxylic acid compounds and processes for making
hydroxymethylcyclohexane compounds.
Inventors: |
Hembre; Robert Thomas;
(Johnson City, TN) ; Boppana; Venkata Bharat Ram;
(Johnson City, TN) ; Barnicki; Scott Donald;
(Kingsport, TN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Eastman Chemical Company |
Kingsport |
TN |
US |
|
|
Assignee: |
Eastman Chemical Company
Kingsport
TN
|
Family ID: |
52350327 |
Appl. No.: |
15/097731 |
Filed: |
April 13, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14143936 |
Dec 30, 2013 |
9340482 |
|
|
15097731 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C 51/36 20130101;
C07C 51/36 20130101; C07C 2601/14 20170501; C07C 61/08 20130101;
C07C 61/09 20130101; C07C 51/36 20130101 |
International
Class: |
C07C 51/36 20060101
C07C051/36 |
Claims
1. A composition comprising a cyclohexanecarboxylic acid compound
dissolved in a solvent, wherein the solvent comprises at least
about 50% by weight of a tertiary cyclic amide solvent
compound.
2. The composition of claim 1, wherein the at least one tertiary
cyclic amide solvent compound has the structure depicted in formula
I or II: ##STR00003## wherein R is selected from substituted or
unsubstituted alkyl, cycloalkyl, aryl, aryl-substituted alkyl,
cycloalkyl-substituted alkyl, alkyl-substituted aryl, and
alkyl-substituted cycloalkyl, and wherein R has from 1 to 10 carbon
atoms and optionally possesses on or more hydroxyl group.
3. The composition of claim 2, wherein R has one or two carbon
atoms.
4. The composition of claim 2, wherein the at least one tertiary
amide solvent compound has the structure depicted in formula I.
5. The composition of claim 4, wherein R has one or two carbon
atoms.
6. The composition of claim 4, wherein R is an unsubstituted alkyl
group selected from methyl and ethyl.
7. The composition of claim 4, wherein R is 2-hydroxyethyl
8. The composition of claim 1, wherein at least about 80% by weight
of the solvent is at least one tertiary cyclic amide solvent
compound.
9. The composition of claim 1, wherein the solvent further
comprises isopropyl alcohol.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/143,936, filed on Dec. 30, 2013, the disclosure of
which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates to hydrogenation processes for making
cyclohexane compounds. More specifically, this invention relates to
hydrogenation processes in the presence of tertiary amide solvent
compounds, as well as compositions that can result from such
processes.
BACKGROUND OF THE INVENTION
[0003] Cyclohexanecarboxylic acid compounds and
hydroxymethylcyclohexane compounds are important commercial
chemicals. For example, diacids such as 1,4-cyclohexanedicarboxylic
acid (CHDA) and 1,3-cyclohexanedicarboxylic acid and diols such as
1,4-cyclohexanedimethanol (CHDM) are useful monomers in formation
of a wide variety of polymers and intermediates in a variety of
additional reactions. 1,4-CHDA production can act as an
intermediate for the synthesis of 1,4-cyclohexanedimethanol (CHDM).
The monoacid cyclohexanecarboxylic acid is used as a raw material
in synthesis of other compounds, and cyclohexanecarboxylic acid and
several of its derivatives are useful as flavor and fragrance
agents. Many cyclohexanecarboxylic acid compounds are prepared by
hydrogenation of benzenecarboxylic acids. For example, there exists
processes for synthesis of 1,4-CHDA from terephthalic acid (TPA).
Many such processes suffer the drawback that they use compounds
that are poor solvents for TPA. Processes also exist that include
the conversion of TPA to its alkaline metal salts, and subsequent
hydrogenation of such salts. Such processes, however, involve an
additional process step as well as issues associated with
conversion back to acids and removal and management of inorganic
salts and acids in the process. Thus, there is a continuing need
for improvement of processes for making cyclohexanecarboxylic acid
and hydroxymethylcyclohexane compounds.
BRIEF SUMMARY OF THE INVENTION
[0004] Processes are provided involving use of tertiary cyclic
amide solvent compounds as solvents in hydrogenation reactions.
Such reactions demonstrate significantly more favorable results
than other compounds having solubility characteristics similar to
that of tertiary cyclic amide solvent compounds.
[0005] The invention thus provides processes for making at least
one cyclohexanecarboxylic acid compound that include combining at
least one benzenecarboxylic acid compound, at least one solvent and
hydrogen in the presence of at least one aryl hydrogenation
catalyst under conditions effective to hydrogenate the benzene ring
on at least some of the at least one benzenecarboxylic acid
compound, wherein the at least one aryl hydrogenation catalyst
includes at least one rhodium or ruthenium compound on a solid
support and the at least one solvent includes at least one tertiary
cyclic amide solvent compound.
[0006] The invention further provides processes for making at least
one hydroxymethylcyclohexane compound includes combining hydrogen
with:
[0007] a. at least one cyclohexanecarboxylic acid compounds and
[0008] b. at least one solvent that includes at least one tertiary
cyclic amide solvent compound,
in the presence of at least one acid hydrogenation catalyst under
conditions effective to hydrogenate carboxylic acid groups on at
least some of the at least one cyclohexanecarboxylic acid
compounds.
[0009] The invention further provides processes for making at least
one hydroxymethylcyclohexane compound, the process including:
[0010] a. combining hydrogen, at least one benzenecarboxylic acid
compound and at least one solvent in the presence of at least one
aryl hydrogenation catalyst containing at least one rhodium or
ruthenium compound on a solid support in a first reaction zone
under first reaction conditions effective to hydrogenate the
benzene ring on at least some of the at least one benzenecarboxylic
acid compound to produce a first composition containing at least
one cyclohexanecarboxylic acid and the at least one solvent;
[0011] b. combining at least some of the first composition with
hydrogen and an acid hydrogenation catalyst in a second reaction
zone under second reaction conditions effective to hydrogenate the
acid groups on at least some of the at least one
cyclohexanecarboxylic acid to produce a second composition
containing at least one hydroxymethylcyclohexane compound and the
at least one solvent,
wherein the solvent contains at least one tertiary cyclic amide
solvent compound. In some embodiments of the type described by this
paragraph, at least about 50% of the at least one solvent fed to
first reaction zone is fed to the second reaction zone, and in some
embodiments, at least about 80% of the at least one solvent fed to
first reaction zone is fed to the second reaction zone. In some
embodiments of the type described by this paragraph, the process
further includes processing the second composition in at least one
first separation zone to remove at least some of the catalyst from
the second composition. In some embodiments of the type described
by this paragraph, the process further includes processing at least
some of the second composition in at least one second separation
zone to concentrate the hydroxymethylcyclohexane compound in a
crude product stream and to concentrate the at least one solvent
compound in a recovered solvent stream. In some embodiments of the
type described in the previous sentence, the process further
includes recycling at least some of the recovered solvent stream to
the first hydrogenation zone.
[0012] In some embodiments of the methods, at least one tertiary
cyclic amide solvent compound has the structure depicted in formula
I or II:
##STR00001##
wherein R is selected from alkyl, cycloalkyl, aryl,
aryl-substituted alkyl, cycloalkyl-substituted alkyl,
alkyl-substituted aryl, and alkyl-substituted cycloalkyl, and
wherein R has from 1 to 10 carbon atoms and optionally possesses
one hydroxyl group. In some embodiments, R has one or two carbon
atoms. In some embodiments, R is an unsubstituted alkyl group. In
some embodiments, R is methyl or ethyl. In some embodiments, R is
2-hydroxyethyl. In some embodiments, the at least one tertiary
amide solvent compound has the structure depicted in formula I.
[0013] In some embodiments of the above processes at least about
50% by weight of the solvent is at least one tertiary cyclic amide
solvent compound. In some embodiments, at least about 80% by weight
of the solvent is at least one tertiary cyclic amide solvent
compound. In some embodiments, the solvent further includes
isopropyl alcohol.
[0014] In some embodiments of the processes that involve at least
one benzenecarboxylic acid compound, the at least one
benzenecarboxylic acid compound includes at least one monoacid. In
some embodiments, the at least one benzenecarboxylic acid compound
includes at least one diacid. In some embodiments, the at least one
diacid is selected from terephthalic acid, isophthalic acid, or
combinations thereof. In some embodiments, the at least one diacid
is isophthalic acid. In some embodiments, the at least one diacid
is terephthalic acid.
[0015] In some embodiments, the at least one cyclohexanecarboxylic
acid compound includes 1,4 cyclohexanedicarboxylic acid. In some
embodiments, the at least one cyclohexanecarboxylic acid compound
includes 1,3 cyclohexanedicarboxylic acid. In some embodiments, the
at least one cyclohexanecarboxylic acid compound includes a blend
of 1,3 cyclohexanedicarboxylic acid and 1,4 cyclohexanedicarboxylic
acid.
[0016] In some embodiments of processes that include at least one
aryl hydrogenation catalyst, the at least one aryl hydrogenation
catalyst includes at least one ruthenium compound on a solid
support. In some embodiments, the solid support is carbon. In some
embodiments of the type described in this paragraph, conditions
effective to hydrogenate the benzene ring on at least some of the
at least one benzenecarboxylic acid compound include pressure of
from about 1,000 to about 1,500 psig and temperature of from about
80 to about 190.degree. C.
[0017] In some embodiments of processes that include at least one
aryl hydrogenation catalyst, the at least one aryl hydrogenation
catalyst includes at least one aryl hydrogenation catalyst includes
at least one rhodium compound on a solid support. In some
embodiments, the solid support is carbon. In some embodiments of
the type described in this paragraph, conditions effective to
hydrogenate the benzene ring on at least some of the at least one
benzenecarboxylic acid compound include pressure of from about 400
to about 600 psig and temperature of from about 80 to about
120.degree. C. In some embodiments of the type described in the
first sentence of this paragraph, the solvent further includes
isopropyl alcohol and conditions effective to hydrogenate the
benzene ring on at least some of the at least one benzenecarboxylic
acid compound include pressure of from about 150 to about 400 psig
and temperature of from about 80 to about 120.degree. C.
[0018] In some embodiments that involve an acid hydrogenation
catalyst, the acid hydrogenation catalyst includes (a) a ruthenium
compound; and (b) a tridentate triphosphine compound selected from
1,1,1-tris(diarylphosphinomethyl)alkyl in which the alkyl is
substituted or unsubstituted. In some embodiments, the ruthenium
compound and the tridentate triphosphine compound are the same
compound. In some embodiments, wherein the ruthenium compound is
selected from ruthenium carboxylates, ruthenium acetylacetones,
ruthenium hydride complexes, ruthenium carbonyl compounds,
ruthenium halides, ruthenium oxides, ruthenium phosphine complexes,
and compositions of two or more of the foregoing; and the
tridentate triphosphine compound is selected from
tris(diphenylphosphinomethyl)alkyl or substituted alkyl. In some
embodiments, ruthenium compound includes
ruthenium(III)acetylacetonate. In some embodiments, the tridentate
triphosphine compound includes
1,1,1-tris(diphenylphosphinomethyl)ethane. In some embodiments, the
ruthenium compound is selected from ruthenium carboxylates,
ruthenium acetylacetones, ruthenium hydride complexes, ruthenium
carbonyl compounds, ruthenium halides, ruthenium oxides, ruthenium
phosphine complexes, and compositions of two or more of the
foregoing; and the tridentate triphosphine compound is selected
from tris(diphenylphosphinomethyl)alkyl or substituted alkyl. In
some embodiments, the ruthenium compound includes
ruthenium(III)acetylacetonate. In some embodiments, the tridentate
triphosphine compound includes
1,1,1-tris(diphenylphosphinomethyl)ethane.
[0019] In some embodiments that involve an acid hydrogenation
catalyst the process further includes combining the acid
hydrogenation catalyst with a promoter selected from Lewis acids,
protic acids having an ionization constant (K.sub.i) of
5.times.10.sup.-3 or greater, onium salts, and compositions of two
or more of the foregoing. In some embodiments, the promoter is
selected from ammonium hexafluorophosphate, tetrabutylammonium
hexafluorophosphate, tetraphenylphosphonium bromide, sodium
tetraphenyl borate, ammonium tetrafluoroborate, tetramethyl
ammonium tetrafluoroborate, toluenesulfonic acid, phosphoric acid,
triflic acid, sulfuric acid, methanesulfonic acid, trifluoroacetic
acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid,
and compositions of two or more of the foregoing. In some
embodiments, wherein the promoter is selected from
tetrabutylammonium hexafluorophosphate, triflic acid,
toluenesulfonic acid, dodecylbenzenesulfonic acid,
dinonylnaphthalenesulfonic acid, and compositions of two or more of
the foregoing.
[0020] In some embodiments that involve an acid hydrogenation
catalyst, the acid hydrogenation is performed under reaction
conditions that include a pressure of from about 500 to about 3,000
psig and a temperature of from about 100 to about 240.degree.
C.
[0021] The invention further provides compositions that include at
least one cyclohexanecarboxylic acid and a solvent of any of the
types described above. The invention further provides compositions
that include at least one hydoxymethylcyclohexane compound and a
solvent of any of the types described above.
BRIEF DESCRIPTION OF THE DRAWING
[0022] FIG. 1 is a depiction of one embodiment of the invention in
which a benzenecarboxylic acid is hydrogenated to result in a
cyclohexanedicarboxylic acid compound which is, in turn,
hydrogenated to result in a hydroxymethylcyclohexane compound.
DETAILED DESCRIPTION
[0023] The invention provides processes that include hydrogenation
reactions in the presence of at least one tertiary cyclic amide
solvent compound. In some embodiments, the process includes
hydrogenation of the unsaturated carbons on the benzene ring of at
least one benzenecarboxylic acid in the presence of the tertiary
cyclic amide solvent compound to form a cyclohexanecarboxylic acid
compound. In some embodiments, the process includes hydrogenation
of at least one carboxylic acid group on at least one
cyclohexanecarboxylic acid compound in the presence of the tertiary
cyclic amide solvent compound to form a hydroxymethylcyclohexane
compound. The invention further provides two-step processes in
which the benzene ring of at least one benzenecarboxylic acid
compound is hydrogenated to form at least one cyclohexanecarboxylic
acid compound, and one or more acid group on the at least one
cyclohexanecarboxylic acid compound is then further hydrogenated in
a second step to form at least one hydroxymethylcyclohexane
compound from the first step, and both steps are performed in the
presence of a tertiary cyclic amide solvent compound. Because the
solvents can be the same in both steps, the invention further
provides embodiments in which the second step is performed in the
presence of some, most or substantially all of the solvent that was
present in the first step. The invention thus may afford the
opportunity in some embodiments to reduce or to eliminate
separation of the cyclohexanecarboxylic acid compounds from the
solvent used in the first step.
[0024] Solvents and Tertiary Cyclic Amide Solvent Compounds
[0025] The solvent in the hydrogenation process includes a tertiary
cyclic amide solvent compound. As used throughout this application,
"cyclic amide solvent compounds" or "cyclic amide compounds" refers
to cyclic compounds (commonly referred to as lactam compounds)
containing an amide group in which both the nitrogen of the amide
group and the carbon of the carbonyl moiety of the amide group are
members of the cyclic rings. Some examples include four membered
rings based on 6-lactam (2-azetidinone), five membered rings based
on y-lactam (2-pyrrolidone), six membered rings based on O-lactam
(2-piperidone) and seven membered rings based on c-lactam
(azepan-2-one or caprolactam) compounds. The cyclic amide solvent
compounds of the present invention are tertiary cyclic amides,
meaning that the nitrogen atom in the amide is bonded to three
carbon atoms. Two of the carbon atoms are members of the ring, and
the third carbon is part of a group referred to as "R," herein. For
example, tertiary amides based on 2-pyrrolidone and 2-piperidone
have the structure shown in formula I and II:
##STR00002##
[0026] Although 2-pyrrolidone and 2-piperidone are used as
illustrations above, embodiments exist in which other tertiary
cyclic amide solvent compounds are used, and the descriptions of
the R group herein can apply to the corresponding group on any
tertiary cyclic amide. As used throughout this application,
"tertiary cyclic amide solvent compounds" refers to all such
compounds. In some embodiments, the tertiary cyclic amide solvent
compound is selected from compounds having the structure shown in
formula I or II or combinations of two or more thereof. In some
embodiments, the tertiary cyclic amide solvent compound is selected
from compounds having the structure shown in formula I or
combinations of two or more thereof. In some embodiments, the
tertiary cyclic amide solvent compound is selected from compounds
having the structure shown in formula II or combinations of two or
more thereof.
[0027] The R group in the tertiary cyclic amide solvent compound is
selected from substituted or unsubstituted alkyl, cycloalkyl, aryl,
aryl-substituted alkyl, cycloalkyl-substituted alkyl,
alkyl-substituted aryl, and alkyl-substituted cycloalkyl, and
wherein R has 1 to 10 carbon atoms and optionally possesses one or
more hydroxyl (-OH) groups. In some embodiments, the R group
possesses a single terminal hydroxyl group (i.e. a hydroxyl group
bonded to a carbon that is furthest from the nitrogen). Embodiments
exist in which R is an alkyl having 1 to 10 carbon atoms, 1 to 6
carbon atoms, 1 to 4 carbon atoms, 1 to 3 carbon atoms or 1 to 2
carbon atoms, each of the foregoing having embodiments that possess
a terminal hydroxyl groups and embodiments that do not. Embodiments
of each of these exist in which the alkyl group includes a hydroxyl
group or where it does not. Some examples of alkyl groups suitable
for R include methyl, ethyl, n-propyl, isopropyl, n-butyl,
isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and
2-hydroxyethyl. In some embodiments, R is selected from methyl and
ethyl. In some embodiments, R is selected from methyl, ethyl, and
2-hydroxyethyl. In some embodiments, R is methyl (e.g.
n-methyl-2-pyrrolidone or n-methyl-2-piperidone). In some
embodiments, R is ethyl (e.g. n-ethyl-2-pyrrolidone or
n-ethyl-2-piperidone). In some embodiments, R is 2-hydroxyethyl
(e.g. n-2-hydroxyethyl-2-pyrrolidone or
n-2-hydroxyethyl-2-piperidone). Combinations of two or more
compounds of the foregoing description may also be used, including
combinations of compounds having differing R groups.
[0028] In some embodiments, the at least one tertiary cyclic amide
solvent compound constitute(s) at least about 50% of the solvent.
In some embodiments, the at least one tertiary cyclic amide solvent
compound constitute(s) at least about 75% of the solvent. In some
embodiments, the at least one tertiary cyclic amide solvent
compound constitute(s) at least about 85% of the solvent. In some
embodiments, the at least one tertiary cyclic amide solvent
compound constitute(s) at least about 90% of the solvent. In some
embodiments, the at least one tertiary cyclic amide solvent
compound constitute(s) at least about 95% of the solvent. A
tertiary cyclic amide solvent compound may be used alone, in blends
of two or more tertiary cyclic amide solvent compounds, in blends
with any other types of solvent compounds, or both. Where other
compounds are used in the solvent, the identity is not critical and
any compound that does not unacceptably interfere with the
hydrogenation reaction. Some examples include water, methanol,
ethanol, n-propanol, isopropyl alcohol, and n-butanol. In some
embodiments, the at least one additional solvent compound includes
at least one secondary alcohol. In some embodiments, the secondary
alcohol has from 1 to 8 carbon atoms. Embodiments exist in which
the secondary alcohol is isopropyl alcohol, 2-butanol, 3-pentanol,
2-pentanol, 3-hexanol, 2-hexanol or skeletal isomers thereof or a
cyclopentanol, or a cyclohexanol thereof or combinations of two or
more of the foregoing. In some embodiments, the amount of solvent
includes from about 1.0 to about 40 weight percent of at least one
secondary alcohol. Embodiments exist in which the amount of at
least one secondary alcohol is from about 1.0 to about 30, from
about 1.0 to about 20, from about 1.0 to about 15 weight percent,
from about 1.0 to about 10 weight percent, from about 10 to about
40 weight percent, from about 10 to about 30 weight or from about
5.0 to about 20 weight percent based on the total weight of the
solvent.
[0029] The solvent compounds are part of the feed to a
hydrogenation process and are present in an amount effective to
provide adequate dissolution or suspension of the feed materials.
In some embodiments, the solvent compounds together (i.e. the one
or more tertiary cyclic amide solvent compounds and any other
solvent compounds) is at least about 50 wt. % of the feed to the
hydrogenation process. Embodiments also exist in which the solvent
compounds are at least about 75 wt. %, at least about 80 wt. % or
at least about 90 wt. % of the feed to the hydrogenation
process.
[0030] Hydrogenation of Benzenecarboxylic Acids
[0031] In some embodiments, the process includes hydrogenation of
the benzene ring carbons of at least one benzenecarboxylic acid. In
such embodiments, the process includes combining at least one
benzenecarboxylic acid compound, at least one solvent and hydrogen
in the presence of an aryl hydrogenation catalyst wherein the
solvent has the characteristics described above. As used throughout
this application, "benzenecarboxylic acid" means a compound
containing a six carbon aromatic ring or "benzene ring" in which at
least one of the carbons in the ring is covalently bonded to the
carbon of a carboxylic acid group. In some embodiments, the
compound has a single carboxylic acid group bonded thereto. In some
embodiments, the compound has two carboxylic acid groups bonded
thereto. In some embodiments, the compound has 3 carboxylic acid
groups bonded thereto. Embodiments also exist in which the number
of carboxylic acid groups may be described as a range, such as 1 to
3, 1 to 6 or 1 to 2. Some examples of benzenecarboxylic acids
include: the monoacids benzoic acid, 2-methylbenzoic acid,
3-methylbenzoic acid, 4-methylbenzoic acid, ethyl benzoic acid,
4-carboxybenzaldehyde, p-hydroxymethylbenzoic acid and 2-methyl
terephthalic acid; the diacids benzene-1,4-dicarboxylic acid
(terephthalic acid), benzene-1,3-dicarboxylic acid (isophthalic
acid) and benzene-1,2-dicarboxylic acid (phthalic acid); the
triacids trimellitic acid and hemimellitic; and other poly acids
such as trimesic acid, as well as any combination of any two or
more of the foregoing. In some embodiments, the at least one
benzenecarboxylic acid includes one or more diacids. In some
embodiments, the benzenecarboxylic acid is selected from
terephthalic acid, isophthalic acid or combinations thereof. In
some embodiments, the benzenecarboxylic acid is terephthalic acid.
In some embodiments, the benzenecarboxylic acid is isophthalic
acid. In some embodiments, the benzenecarboxylic acid is a blend of
terephthalic acid and isophthalic acid. In some embodiments, the
benzenecarboxylic acid is benzoic acid. Specific embodiments of the
process exist for each of the foregoing, and embodiments exist for
blends of any two or more of the foregoing.
[0032] The hydrogenation of the benzenecarboxylic acid occurs in
the presence of an aryl hydrogenation catalyst. The aryl
hydrogenation catalyst may be any hydrogenation catalyst that is
effective for the reduction of an aromatic ring. In some
embodiments, for example, the aryl hydrogenation catalyst can
include a Group VIII metal (Groups 8, 9, and 10 according to IUPAC
numbering) supported on a catalyst support material containing
carbon, silica, alumina, silica-alumina, zirconium oxide
(zirconia), titanium dioxide (titania), chromium oxides, graphite,
silicon carbide, or combinations thereof. In some embodiments, the
support material in the aryl hydrogenation catalyst is selected
from carbon, silicon carbide, graphite and zirconium oxide or
combinations thereof. In some embodiments, the support material in
the aryl hydrogenation catalyst is selected from carbon, silicon
carbide and graphite. In some embodiments, the support material is
carbon. Some examples of carbon support materials include activated
carbon, carbon nanotubes, carbon powder, carbon rods, carbon black
carbon soot and carbon nanofibers. In some embodiments, the carbon
support material is selected from carbon nanotubes and activated
carbon. In some embodiments, the carbon support material is
activated carbon.
[0033] In some embodiments, the Group VIII metal in the aryl
hydrogenation catalyst is ruthenium. In some embodiments, the Group
VIII metal in the aryl hydrogenation catalyst is rhodium. In some
embodiments of the present invention the total amount of Group VIII
metal present may be about from about 0.1 to about 10 weight
percent based on the total weight of the aryl hydrogenation
catalyst (i.e. including support). Embodiments exist for a wide
variety of such ranges. The lower limit of such ranges may be about
0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about
0.7, about 0.8, about 0.9, about 1.0, about 2.0, about 3.0, about
4.0, about 5.0, about 6.0, about 7.0, about 8.0 or about 9.0. The
upper limit of such ranges may be about 0.2, about 0.3, about 0.4,
about 0.5, about, 0.6, about 0.7, about 0.8, about 0.9, about 1.0,
about 2.0, about 3.0, about 4.0, about 5.0, about 6.0, about 7.0,
about 8.0, about 9.0 or about 10.0. The range of the weight percent
of the Group VIII metal may be any combination of any of the
foregoing lower limits with any of the foregoing upper limits. For
example, in some embodiments the aryl hydrogenation catalyst can
contain from about 2.0 to about 8.0 weight percent rhodium
supported on carbon. In some embodiments of the present invention
the catalyst can contain from about 0.5 to about 5.0 weight percent
ruthenium on carbon wherein the weight percentages are based on the
total weight of the aryl hydrogenation catalyst, i.e., the total
weight of the support material plus the Group VIII metal.
[0034] The aryl hydrogenation catalyst may be in any conventional
form such as, for example, in the form of extrudates, granules, and
pellets for use in fixed-bed reactor processes and powder for
slurry processes. The shape of the supports may be, but are not
limit to, cylinders, spheres, stars or any type of multiple-lobe
shapes. Depending on the particular support material employed
and/or the method used to prepare an aryl hydrogenation catalyst,
the Group VIII metal may be deposited primarily on the surface of
the support or distributed substantially throughout the
support.
[0035] The aryl hydrogenation catalyst may be prepared by
conventional techniques such as impregnation of one or more Group
VIII metals or Group VIII metal compounds on or into the support
material. The Group VIII metals may be provided as zero valent
metals or as oxidized metals in the form of compounds such as salts
of inorganic or organic acids and organometallic complexes. In some
embodiments, the Group VIII metal is present as a zero valent
metal. In some embodiments, the support materials may be
impregnated with one or more Group VIII metals by immersing the
support material in a solution of a Group VIII metal compound in a
suitable solvent such as water or an organic solvent. The support
material then is dried and the metal compound is reduced to a Group
VIII metal.
[0036] The benzenecarboxylic acid compound, solvent and hydrogen
are combined in the presence of the aryl hydrogenation catalyst
under conditions effective to cause hydrogenation of the benzene
ring. In some embodiments, the pressure in the reactor is from
about 80 to about 2,000 pounds per square inch gage (psig) and the
temperature in the reactor is from about 20.degree. C. to about
200.degree. C. In some embodiments the temperature is from about
60.degree. C. to about 180.degree. C. In some embodiments in which
at least one Group VIII metal used in the aryl hydrogenation
catalyst is ruthenium, the temperature is from about 120.degree. C.
to about 200.degree. C., and in some such embodiments the
temperature is from about 120.degree. C. to about 160.degree. C. In
some embodiments in which at least one Group VIII metal used in the
aryl hydrogenation catalyst is rhodium, the temperature is from
about 80.degree. C. to about 200.degree. C., and in some such
embodiments the temperature is from about 80.degree. C. to about
150.degree. C., or from about 90.degree. C. to about 120.degree.
C.
[0037] In some embodiments the pressure is from about 50 psig to
about 3000 psig, in some embodiments the pressure is from about 300
psig to about 2500 psig, in some embodiments the pressure is from
about 500 psig to about 3000 psig and in some embodiments from
about 500 to about 2000. In some embodiments in which at least one
Group VIII metal used in the aryl hydrogenation catalyst is
ruthenium, the pressure is from about 1000 psig to about 3000 psig,
in some such embodiments the pressure is from about 1200 psig to
about 2500 psig, in some such embodiments the pressure is from
about 1200 psig to about 2200 psig, in some such embodiments the
pressure is from about 1300 psig to about 2100 psig and in some
such embodiments the pressure is from about 1300 psig to about 2600
psig. In some embodiments in which at least one Group VIII metal
used in the aryl hydrogenation catalyst is rhodium, the pressure is
from about 15 psig to about 800 psig, in some such embodiments the
pressure is from about 15 to about 600 psig, in some such
embodiments the pressure is from about 50 to about 600 psig, in
some such embodiments the pressure is from about 50 to about 150
psig, in some such embodiments the pressure is from about 100 to
about 250 psig, in some such embodiments the pressure is from about
100 to about 250 psig, in some such embodiments the pressure is
from about 80 psig to about 800 psig, in some such embodiments the
pressure is from about 80 to about 600 psig, in some such
embodiments the pressure is from about 400 to about 600 psig, in
some such embodiments the pressure is from about 80 to about 150
psig, in some such embodiments the pressure is from about 150 to
about 250 psig and in some such embodiments the pressure is from
about 150 to about 250 psig. Any combination of the above
temperature and pressure ranges in the previous two paragraphs may
be used.
[0038] The benzenecarboxylic acid and solvent may be fed to the
hydrogenation process by any workable means (i.e. together or
separately as workable). In some embodiments, the benzenecarboxylic
acid is dissolved or dispersed in the solvent and the two are fed
together. Any workable concentration of the benzenecarboxylic acid
in solvent may be used. In some embodiments, the mixture contains
from about 5 to about 60 wt. % benzenecarboxylic acid. In some
embodiments, the amount is from about 5 to about 40 wt. %, from
about 10 to about 20 wt. %, from about 10 to about 30 wt. %, from
about 20 to about 40 wt. %, from about 10 to about 50 wt. %, from
about 30 to about 40 wt. %, from about 10 to about 30 wt. %, from
about 20 to about 60 wt. %, from about 20 to about 50 wt. %.
[0039] The hydrogenation of benzenecarboxylic acids of the present
invention can be carried out in any suitable batch reactor or
continuous reactor, such as pressurized fixed bed reactors,
multitubular fixed bed reactors, continuous stirred tank reactors,
radial flow reactors, plug flow reactors, fluidized bed reactors,
jet loop reactors, trickle bed reactors, bubble column reactors. In
some embodiments, the duration or contact of the benzenecarboxylic
acid with the hydrogen and the aryl hydrogenation catalyst is from
about 0.25 to about 10.0 hours, in some embodiments from about 1.0
to about 6.0 hours, in some embodiments from about 2.0 to about 4.0
hours, in some embodiments from about 0.1 hour to about 2.0 hours,
in some embodiments from about 0.1 hour to about 1.0 hour and in
some embodiments from about 0.2 hour to about 0.8 hour.
[0040] The process may be operated at any weight hour space
velocity that is useful to the process. Weight hour space velocity
is the ratio of mass feed rate for TPA (unit weight per hour) to
mass of catalyst (including support). In some embodiments, the
weight hour space velocity is from about 0.1 to about 2.0.
Embodiments also exist in which the weight hour space velocity is
from about 0.1 to about 1.0, or from about 0.1 to about 0.5.
[0041] Hydrogenation of the benzenecarboxylic acid produces a
cyclohexanecarboxylic acid. As used throughout this application,
"cyclohexanecarboxylic acid" means a cyclohexane compound in which
at least one of the carbons in the cyclohexane ring has at least
one carboxylic acid group bonded thereto. Some examples include
compounds that can be produced by hydrogenation of the benzene ring
of any of benzenecarboxylic acids discussed above. In some
embodiments, cyclohexanecarboxylic acids include the monoacid
cyclohexanecarboxylic acid and diacids such as
1,4-cyclohexanedicarboxylic acid and 1,3-cyclohexanedicarboxylic
acid or triacids such as 1,3,5-cyclohexanetricarboxylic acid or
1,2,5-cyclohexanetricarboxylic acid. In embodiments in which the
"cyclohexanecarboxylic acid" is a diacid, the diacid may be
described by its cis/trans ratio, in reference to the relative
positions of the two acid groups in relation to the cyclohexane
ring. In some embodiments of the invention, the cis/trans ratio of
the resulting cyclohexanedicarboxylic acid is from about 3.0 to
about 5.2, in some embodiments from 3.0 to 4.5 and in some
embodiments from about 4.0 to about 5.0.
[0042] Hydrogenation of cyclohexanecarboxylic Acids
[0043] The invention also provides processes that include
hydrogenation of at least one carboxylic acid group on at least one
cyclohexanecarboxylic acid compound. In such embodiments, the
process includes contacting the at least one cyclohexanecarboxylic
acid compound with the solvent and hydrogen in the presence of an
acid hydrogenation catalyst to form a hydroxymethylcyclohexane
compound. The solvent includes tertiary cyclic amide solvent
compound and is otherwise as described above. Optionally, a
promoter may also be present.
[0044] Any cyclohexanecarboxylic acid compound (as described above)
may be used in this process. The solvent may be any of the solvents
described above, and specifically includes the tertiary cyclic
amide solvent compound. The acid hydrogenation catalyst may be any
hydrogenation catalyst that is effective for the reduction of a
carboxylic acid group to a hydroxymethyl group (i.e. CH.sub.2OH).
In some embodiments, the acid hydrogenation catalyst is a
homogeneous catalyst that is dissolved or dispersed in the solvent.
In some embodiments, the catalyst composition includes: (a) a
ruthenium, rhodium, iron, osmium or palladium compound; and (b) an
organic phosphine. In some embodiments, the catalyst of the present
invention is a ruthenium catalyst. The ruthenium compound is not
particularly limiting and can be any ruthenium source that is
soluble in the solvent of the invention. Some example compounds
include ruthenium salts, hydride complexes, carbonyl compounds,
halides, oxides, phosphine complexes, and combinations of two or
more of the foregoing. Suitable ruthenium salts include ruthenium
carboxylates and acetylacetonates. For example, the ruthenium
compound can include the acetonylacetonate complex of
ruthenium(III). In some embodiments, the ruthenium compounds can be
converted to active species under the reaction conditions, such as
nitrates, sulfates, carboxylates, beta diketones, and carbonyls.
Ruthenium oxide, carbonyl ruthenates and complex compounds of
ruthenium, including hydridophosphineruthenium complexes, may also
be used. Some examples include ruthenium nitrate, ruthenium
dioxide, ruthenium tetroxide, ruthenium dihydroxide, ruthenium
acetylacetonate, ruthenium acetate, ruthenium maleate, ruthenium
succinate, tris-(acetylacetone)ruthenium, triruthenium
dodecacarbonyl, tetrahydrido(decacarbonyl)tetraruthenium,
hydrido(undecacarbonyl)triruthenate
cyclo-pentadienyl(dicarbonyl)ruthenium dimer,
(norbornadiene)bis(methallyl)ruthenium,
(cyclooctadiene)bis(methallyl)ruthenium,
bis(ethylene)bis(methallyl)ruthenium, ruthenium dioxide, ruthenium
tetraoxide, ruthenium dihydroxide and
bis(tri-n-butylphosphine)tricarbonylruthenium.
[0045] In some embodiments, the ruthenium compound is a tridentate
phosphine. Some examples of tridentate phosphine compounds include
tris-1,1,1-(diphenylphosphinomethyl)methane,
tris-1,1,1-(diphenylphosphinomethyl)ethane,
tris-1,1,1-(diphenylphosphinomethyl)propane,
tris-1,1,1-(diphenylphosphino-methyl)butane,
tris-1,1,1-(diphenylphosphinomethyl)2,2dimethylpropane,
tris-1,3,5-(diphenylphosphinomethyl)cyclohexane,
tris-1,1,1-(dicyclohexylphosphinomethyl)ethane,
tris-1,1,1-(dimethylphosphinomethyl)ethane,
tris-1,1,1-diethylphosphinomethyl)ethane,
tris-1,1,1-(dimethylphospholylmethyl)ethane,
1,5,9-triethyl-1,5-9-triphosphacyclododecane,
1,5,9-triphenyl-1,5-9-triphosphacyclododecane,
tris(2-diphenylphosphinoethyl)amine, and
tris(diisopropylphosphinomethyl)amine. In some embodiments,
tris-1,1,1-(diphenylphosphinomethyl)-ethane is used. Advantageous
results can be achieved with tridentate facially capped phosphines
such as tris-1,1,1-(diarylphosphinomethyl)alkane and
tris-1,1,1-(dialkylphosphinomethyl)alkane.
[0046] In some embodiments, the catalyst composition includes: (a)
a ruthenium compound; (b) a tridentate triphosphine compound
selected from 1,1,1-tris(diarylphosphinomethyl)alkyl or substituted
alkyl; and (c) a promoter selected from Lewis acids, protic acids
having an ionization constant (K.sub.i) of 5.times.10.sup.-3 or
greater, onium salts, and combinations of two or more of the
foregoing; wherein the catalyst components. In some embodiments,
(a) and (b) are the same compound.
[0047] In some embodiments, the tridentate triphosphine is selected
from 1,1,1-tris(diarylphosphinomethyl)alkyl and substituted alkyl.
The alkyl substituent can have 1 to 40 carbon atoms. Some examples
of alkyl groups include methyl, ethyl, propyl, butyl, pentyl,
isobutyl, isopropyl, isopentyl, and the like. The alkyl group can
be substituted with any group that does not interfere with the
hydrogenation reaction such as, for example, hydroxyl, ether,
halogen, sulfonic acid, carboxylic acid, and the like. The aryl
group of the tridentate triphosphine compound may have from 6 to 20
carbon atoms. Some examples of the aryl groups include carbocyclic
aryl groups such as phenyl, naphthyl, anthracenyl, and substituted
derivatives thereof in which one or more substituent groups can
replace hydrogen at any carbon position on the aromatic ring(s).
Some examples of substituent groups include one or more groups
selected from alkyl, alkoxy, cycloalkoxy, formyl, alkanoyl,
cycloalkyl, aryl, aryloxy, aroyl, carboxyl, carboxylate salts,
alkoxy-carbonyl, alkanoyloxy, cyano, sulfonic acid, sulfonate salts
and the like. The alkyl moiety of the aforesaid alkyl, alkoxy,
alkanoyl, alkoxycarbonyl and alkanoyloxy groups typically contains
up to about 8 carbon atoms.
[0048] Some representative examples of substituted aryl groups
include 2-fluorophenyl, 2,3,4,5,6-pentafluorophenyl,
3,5-bis(trifluoromethyl)phenyl and the like; a mono- or
di(hydroxy)aryl radical such as 4-hydroxyphenyl, 3-hydroxyphenyl,
2,4-dihydroxyphenyl, and the like; for example, 4-cyanophenyl; a
mono- or di(lower alkyl)aryl radical such as 4-methylphenyl,
2,4-dimethylphenyl, 2-methylnaphthyl, 4-(isopropyl)phenyl,
4-ethylnaphthyl, 3-(n-propyl)phenyl and the like; a mono- or
di(alkoxy)aryl radical, for example, 2,6-dimethoxyphenyl,
4-methoxyphenyl, 3-ethoxyindenyl, 4-(isopropoxy)phenyl,
4-(t-butoxy)phenyl, 3-ethoxy-4-methoxyphenyl and the like; 3- or
4-trifluoromethylphenyl, a mono- or dicarboxyaryl radical such as
4-carboxyphenyl, 4-carboxynaphthyl; a mono- or
di(hydroxymethyl)aryl radical such as 3,4-di(hydroxymethyl)phenyl,
a mono- or di(aminomethyl)aryl radical such as
2-(aminomethyl)phenyl, or a mono- or di(methylsulfonylamino)aryl
radical such as 3-(methylsulfonylamino)naphthyl. In some
embodiments, for example, tridentate triphosphine compound can be
selected from 1,1,1-tris(diphenylphosphinomethyl)alkyl and
substituted alkyl. In some embodiments, the ruthenium compound can
be selected from ruthenium salts, hydride complexes, carbonyl
compounds, halides, oxides, phosphine complexes, and combinations
of two or more of the foregoing; and the tridentate triphosphine
compound can be selected from
1,1,1-tris(diphenylphosphinomethyl)alkyl and substituted alkyl. In
some embodiments, the tridentate triphosphine is
1,1,1-tris(diphenylphosphinomethyl)ethane (also known as
TRIPHOS).
[0049] Optionally, the rate of reaction can be enhanced by the
addition of a promoter selected from Lewis acids, protic acids
having an ionization constant (K.sub.i) of 5.times.10.sup.-3 or
greater, and onium salts. The term "Lewis Acid", as used herein,
refers to the Lewis concept of acid-base equilibria as elaborated
in Chemical Reviews, 69, 251 (1969). An example of a Lewis acid
promoter includes zinc acetonylacetonate.
[0050] Where used, onium salt promoters can include an anionic
component that is derived from a strong acid having an ionization
constant (K.sub.i) of 5.times.10.sup.-3 or greater such as, for
example, phosphoric acid, hexafluorophoshoric acid, hydrobromic
acid, tetrafluoroboric acid, trifluoroacetic acid,
p-toluenesulfonic acid, triflic acid, sulfuric acid, combinations
of two or more of the foregoing, and the like. These anions are
neutral to weak bases in comparison to anions such as, for example,
hydroxides, carbonates, bicarbonates, and carboxylates without
electron-withdrawing substituents. In some embodiments, the onium
salt promoters can include a non-coordinating anion. Some examples
of onium salt promoters include ammonium hexafluorophosphate,
tetrabutylammonium hexafluorophosphate, tetraphenylphosphonium
bromide, ammonium tetrafluoroborate, tetramethyl ammonium
tetrafluoroborate, combinations of two or more of the foregoing and
the like.
[0051] Some examples of protic acids having an ionization constant
(K.sub.i) of 5.times.10.sup.-3 or greater include toluenesulfonic
acid, phosphoric acid, triflic acid, sulfuric acid, methanesulfonic
acid, trifluoroacetic acid, dodecylbenzenesulfonic acid,
dinonylnaphthalenesulfonic acid, and the like. In some embodiments,
the promoter is selected from tetrabutylammonium
hexafluorophosphate, triflic acid, toluenesulfonic acid,
dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, and
combinations of two or more of the foregoing. Combinations of any
one of the above Lewis acids, protic acids, and onium salts also
may be used.
[0052] The cyclohexanecarboxylic acid compound, solvent and
hydrogen are combined in the presence of the acid hydrogenation
catalyst (and optional promoter) under conditions effective to
cause hydrogenation of the carboxylic acid groups. In some
embodiments, the pressure in the reactor is from about 500 to about
5,000 psig and the temperature in the reactor is from about
100.degree. C. to about 250.degree. C. In some embodiments the
temperature is from about 150.degree. C. to about 225.degree. C. In
some embodiments the temperature is from about 100.degree. C. to
about 200.degree. C. In some embodiments the temperature is from
about 100.degree. C. to about 150.degree. C. In some embodiments
the temperature is from about 160.degree. C. to about 210.degree.
C. In some embodiments the pressure is from about 1200 psig to
about 3000 psig, in some embodiments the pressure is from about
1000 psig to about 6000 psig, in some embodiments the pressure is
from about 500 psig to about 3000 psig, in some embodiments the
pressure is from about 1000 psig to about 2500 psig, in some
embodiments the pressure is from about 1000 psig to about 2500
psig, in some embodiments the pressure is from about 1500 psig to
about 2000 psig, in some embodiments the pressure is from about
1400 psig to about 2000 psig and in some embodiments from about
1400 to about 1600 psig. Combinations of any of the above
temperature and pressure ranges are within the scope of the
invention.
[0053] The hydrogenation of cyclohexanecarboxylic acids of the
present invention can be carried out in any suitable batch reactor
or continuous reactor, such as pressurized, continuous stirred tank
reactors or bubble column reactors. In some embodiments, the
duration or contact of the benzenecarboxylic acid with the hydrogen
and the aryl hydrogenation catalyst is from about 0.5 to about 20
hours, in some embodiments from about 2 to about 15 hours and in
some embodiments from about 4 to about 12 hours. In some
embodiments, the weight hour space velocity is from about 0.1 to
about 3.0. Embodiments also exist in which the weight hour space
velocity is from about 0.5 to about 2.0, or from about 0.75 to
about 1.5.
[0054] The reaction converts at least some of the at least one
cyclohexanecarboxylic acid compound to a hydroxymethylcyclohexane
compound. The hydroxymethylcyclohexane product is simply the
product formed by replacing one or more carboxylic acid groups with
hydroxyl groups. Some examples include cyclohexylmethanol,
1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol,
1,2-cyclohexanedimethanol, 1,3,5-cyclohexanetrimethanol and
combinations of any two or more of the foregoing. In some
embodiments, the at least one hydroxymethylcyclohexane compound is
1,4-cyclohexanedimethanol. In some embodiments, the at least one
hydroxymethylcyclohexane compound is 1,3-cyclohexanedimethanol. In
some embodiments, the at least one hydroxymethylcyclohexane
compound is a combination of 1,3-cyclohexanedimethanol and 1,4
cyclohexanedimethanol.
[0055] In embodiments in which the feed cyclohexanecarboxylic acid
is a diacid, the resulting hydroxymethylcyclohexane compound may be
described by its cis/trans ratio, in reference to the relative
positions of the two hydroxymethyl groups in relation to the
cyclohexane ring. In some embodiments of the invention, the
cis/trans ratio of the resulting hydroxymethylcyclohexane compound
is from about 0.20 to about 5.00. Embodiments exist in which the
cis/trans ratio is from about 0.60 to about 1.00, from about 0.20
to about 1.00, from about 1.00 to about 1.50, from about 1.00 to
about 2.00, from about 2.00 to about 3.00, from about 1.00 to about
3.00, from about 1.50 to about 2.50, from about 2.00 to about 4.00,
from about 1.50 to about 3.50, from about 1.50 to about 2.00, from
about 2.00 to about 2.50, from about 2.00 to about 3.50, from about
3.00 to about 3.50, from about 3.00 to about 4.50, from about 3.00
to about 5.00, and from about 3.50 to about 5.00.
[0056] Additional Process Steps
[0057] The process can further involve using separation zones or
separation processes to provide a product stream having a desired
composition. For example, where a dissolved or other homogeneous
catalyst is used, separation techniques may be used to separate the
product and solvent from the catalyst. Any useful separation
technique can be used. Some examples include vapor stripping, flash
distillation, liquid-liquid extraction and membrane separation. For
example, DURAMEM 150 membranes available from Evonik Industries
have been observed to be effective to separate Ruthenium TRIPHOS
catalyst from some hydroxymethylcyclohexane product compositions
when used, for example, in stirred cell filters such as those
available from Sterlitech Corporation. The catalyst, once separated
from the product, can optionally be returned to a reaction zone or
process for reuse. Alternatively, the catalyst solution can be
diluted with an alcohol solvent such as methanol or ethylene glycol
and reused. As another alternative, the reaction mixture can be
partitioned between an aqueous phase and an organic phase, which
will dissolve the catalyst components. The hydroxymethylcyclohexane
compound product can then be recovered from the aqueous phase by
simple distillation while the organic phase can be returned to the
reactor for reuse. It is understood that the separation process
described above can be combined with any of the various embodiments
of the inventive process described herein.
[0058] The process may also include processes or zones to separate
one or more resulting product stream from at least some of the
solvent and to further purify the product stream. For example, a
separation process can concentrate the product compound (e.g. a
cyclohexanecarboxylic acid compound or a hydroxymethyl cyclohexane
compound) in a product stream and concentrate solvent into a
recovered solvent stream. By "concentrating" a product compound, it
is meant that the weight percent of product compound present in
product stream is higher than that in the stream fed to the
separation process or zone. Similarly, by "concentrating" a solvent
compound, it is meant that the weight percent of solvent compound
present in a recovered solvent stream is higher than that in the
stream fed to the separation process or zone. Any useful separation
zone or process can be used. Some examples of separation processes
that may be used in some embodiments include distillation,
filtration, crystallization and extraction and combinations
thereof. Some examples of separation zones that can be used include
vessels or equipment that can perform any of the foregoing
processes. Recovered solvent may be optionally recycled for reuse
in the process. Additional product refining and purification may
occur (for example, through another separation process or zone), or
separation into more than two streams can be achieved in a single
process. In some embodiments of processes involving an aryl
hydrogenation step followed by an acid hydrogenation step
separation zones or processes may or may not be used between the
two hydrogenation steps. In embodiments in which catalyst materials
are also separated from one or more streams, the solvent separation
can occur before, during or after a catalyst separation process. In
some embodiments, catalyst is separated from the product stream in
a first separation zone and solvent is separated from the product
stream in a second separation zone. In some embodiments, the order
is reversed. In some embodiments, catalyst and solvent is separated
from the product stream in a single separation zone. In some
embodiments, one or more of the foregoing separation zones further
serves to separate additional materials.
[0059] Product streams may be processed further to obtain desired
final compositions. Thus, for example, products may be processed
further in one or more additional separation zones of any of the
types described above.
[0060] Processes involving two hydrogenation steps
[0061] The invention further provides processes that include both
of the two types of hydrogenation processes described above. Such
processes involve first hydrogenating at least one
benzenecarboxylic acid compound to form at least one
cyclohexanecarboxylic acid compound, then hydrogenating at least
some of the cyclohexanecarboxylic acid compounds to form
hydroxymethylcyclohexane compounds. Both steps occur in the
presence of a solvent containing at least one tertiary cyclic amide
solvent compound. In some embodiments, at least some of the solvent
from the first hydrogenation step is reused in the second
hydrogenation step without separating it from the
cyclohexanecarboxylic acid compounds. In some embodiments, at least
about 30% of the solvent from the first hydrogenation step is fed
to the second hydrogenation step. In some embodiments, this amount
is at least about 50%, at least about 75%, at least about 85%, at
least about 90% or at least about 95% of the solvent used in the
first hydrogenation step. In some embodiments, the weight percent
of total tertiary cyclic amide solvent compounds in the reaction
composition of the second step is within about 50 percentage points
of the weight percent of total tertiary cyclic amide solvent
compounds in the reaction composition first step. In some
embodiments, this weight percentage in the second step is within
about 40, within about 30, within about 25, within about 20, within
about 15 or within about 10 percentage points of the weight percent
in the first step. As used throughout this application, weight
percentages in a reaction composition refers, in the case of a
continuous process, to the weight percentages of materials during
steady state operation of the continuous reaction process. In the
case of a batch process weight percentages in a reaction
composition refers to the total mass of liquid materials fed to the
batch process.
[0062] One example of such two-step hydrogenation processes is
depicted in FIG. 1, in which the first step is the hydrogenation of
the aromatic ring of terephthalic acid dissolved in
N-methyl-2-pyrrolidone (NMP) to yield 1,4-CHDA and the second step
is the hydrogenation of the carboxylic acid groups to hydroxymethyl
groups yielding 1,4-CHDM. NMP is then stripped from the product and
optionally recycled and the molten product stream is distilled to
provide a purified CHDM stream. In this process the feed stream 10
contains TPA (20-30 wt. %) dissolved in NMP (either entirely fresh
NMP, stream 135, which also contains low boiling components from
stripping column 130, or a combination of the two). The
concentration of TPA is 20-30 wt. % in NMP. Feed stream 10
optionally contains a small amount of a secondary alcohol such as
isopropanol (5-20 wt. %). Stream 10 is gravity fed to first
hydrogenation reactor 20, which is a packed column containing
heterogeneous catalyst (or alternately in another configuration
allowing intimate mixing of stream 10 with the catalyst under a
pressure of hydrogen). Hydrogen 15 is fed to first hydrogenation
reactor 20 at a pressure of 1,000 to 1,500 psig. The temperature in
first hydrogenation reactor 20 is maintained at 80 to 190.degree.
C. The catalyst is a supported zero valent ruthenium metal on a
carbon, or other acid-stable, support. The supported catalyst
contains 1.0 wt. ruthenium. The product solution 30 of reactor 20
contains primarily CHDA in NMP. The residence time in 20 is
designed to achieve a conversion of greater than 95% to CHDA.
Underflow stream 30 is pumped into a second hydrogenation reactor
60. Where desired, a portion of the CHDA produced can be removed
with solvent from the process as stream 40 without hydrogenation to
CHDM. A feed solution 50 of Ruthenium TRIPHOS (or optionally, a
tridentate tridentate compound and a ruthenium compound),
optionally accompanied by a promoter, also in the NMP solvent, is
pumped into second hydrogenation reactor 60 at a rate and
concentration which maintains the concentration of ruthenium in the
reactor relatively constant and compensates for the removal of
ruthenium from ruthenium-recovery in stream 115. A vapor stream of
hydrogen 35 is fed to second hydrogenation reactor 60 at a pressure
of 1,500-2,500 psig while temperature is maintained at
160-210.degree. C. The flow of stream 30 into second hydrogenation
reactor 60 is designed to maintain a residence time in second
hydrogenation reactor 60 adequate to attain a conversion of CHDA to
CHDM of greater than 95%. Stream 70 is a liquid overflow removed
from second hydrogenation reactor 60 and contains CHDM and
Ruthenium TRIPHOS in NMP. This stream is pumped through a membrane
filter 80 selected to retain the ruthenium-based hydrogenation
catalyst in a retentate solution 100 and permeate a crude product
stream 90 containing CHDM and NMP. Optionally, retentate stream 100
is recycled to second hydrogenation reactor 60. Also optionally, a
fraction 105 of retentate stream 100 is pumped to a catalyst
reactivation reactor 110 and following reactivation treatment a
reactivated stream 120 is recombined with stream 100 and pumped
into second hydrogenation reactor 60. A slip-stream, 115, is
withdrawn from catalyst reactivation reactor 110 to be processed to
recover ruthenium for reuse. The rate of removal of ruthenium from
the process is governed by the rate of removal of stream 115 from
catalyst reactivation reactor 110. Product-containing permeate
stream 90 is fed to a solvent stripping distillation column 130,
operated at a temperature of 70-100.degree. C. and pressure of 5-20
torr. Solvent stripping distillation column 130 separates a
lower-boiling stream 135 containing primarily NMP from a higher
boiling product stream 140. The temperature of stripping is
selected in order to give appropriate viscosity to crude product
stream 140. Lower-boiling stream 135 is optionally recycled to
first hydrogenation reactor 20 by combining it with feed 10 (as
shown in dotted line) or feeding it separately (not shown). Crude
product stream 140 is then processed to recover CHDM in low
pressure distillation column 150. A lower-boiling stream containing
CHDM product 160 is recovered from the top of low pressure
distillation column 150 and a distillation heel, 180, is recycled
to solvent stripping distillation column 130 by combining with
stream 90 or by feeding directly (not pictured) to column 130. A
slip stream 170 is removed from 180 as desired to maintain the
fluid properties of stream 180.
[0063] In an alternative embodiment, the catalyst in the packed bed
in the first hydrogenation reactor 20 is supported zero valent
rhodium metal supported on a carbon, or other acid-stable, support.
The supported catalyst contains 5 wt. % rhodium. In this
embodiment, the pressure in first hydrogenation reactor 20 is
400-600 psig and the temperature is 90-120.degree. C. Optionally,
in embodiments in which isopropanol is fed to the first
hydrogenation reactor, the pressure is 150-250 psig.
[0064] In a different alternate embodiment (not pictured) the NMP
is replaced with a solvent that has a higher boiling point than
CHDM (for example, 1-(2-hydroxyethyl)-2-pyrrolidone) and the
functions of columns 130 and 150 are combined into a single column
(not pictured) that is operated at conditions to recover CHDM in an
overhead product stream and to recycle the solvent as part of the
distillation heel. This embodiment may be practiced with either the
ruthenium or the rhodium catalyst embodiments described above.
[0065] In another alternative embodiment, functions of columns 130
and 150 are combined into a single column in which NMP is removed
as a low boiling fraction (and optionally recycled), higher boiling
impurities are removed through an underflow or distillation heel
(and optionally recycled) and product is removed as an intermediate
stream such as a sidedraw between the two streams.
[0066] Resulting Compositions
[0067] The invention further provides compositions that contain at
least one cyclohexanecarboxylic acid compound of the type described
above and at least one cyclic amide solvent compound of the type
described above. Any combination of the two described above may be
in the composition including all compositions that can result from
the processes described herein. Thus, in some embodiments, the
composition includes any combination of one or more additional
solvent compounds of the type described above. Similarly, the
invention further provides compositions that contain at least one
hydroxymethylcyclohexane compound of the type described above and
at least one cyclic amide solvent compound of the type described
above. Again, combination of the two described above may be in the
composition including all compositions that can result from the
processes described herein and, in some embodiments, the
composition includes any combination of one or more additional
solvent compounds of the type described above.
[0068] The invention has been described in detail with particular
reference to embodiments thereof, but it will be understood that
variations and modifications can be effected within the spirit and
scope of the invention. This invention can be further illustrated
by the following examples of embodiments thereof, although it will
be understood that these examples are included merely for purposes
of illustration and are not intended to limit the scope of the
invention unless otherwise specifically indicated. Unless otherwise
indicated, all percentages are by weight.
EXAMPLES
[0069] Hydrogenation of benzenecarboxylic Acids to
cyclohexanecarboxylic Acids
[0070] Except as otherwise stated in the individual examples, the
following procedures were used for hydrogenation of
benzenecarboxylic acids to cyclohexanecarboxylic acids. A 100 ml
autoclave configured in a high pressure AUTO-MATE System Model 4590
(H.E.L. Inc., Grand Rapids, Mich.) with a drop-in catalyst basket
(volume 7 ml) was used. The catalyst was placed in the basket in an
amount equal to the lesser of 2.0 grams or the amount that would
fit in the basket. The autoclave was then pressurized to 1500 psig
with nitrogen. Nitrogen was slowly vented then the feed manifold to
the reactor was then purged twice with by passing hydrogen gas
through at atmospheric temperature. To activate the catalyst, the
reactor was then purged three times by pressurizing with hydrogen
to 150 psig, then venting to ambient pressure each time. Agitation
at 450 rpm commenced and the reactor was heated to 150.degree. C.
Hydrogen was then added to bring the pressure to 1500 psig then
held for 2 hours. The reactor was permitted to cool to room
temperature, agitation was stopped and pressure was released. The
reactor was then placed in a containment box purged with argon to
avoid exposing the autoclave to air during loading. TPA (except
where indicated otherwise), 3g, and 50 grams of solvent (except
where indicated otherwise) were charged to the autoclave. The
agitator was then restarted and held at 450 rpm for 10 minutes.
Nitrogen was slowly vented then the feed manifold to the reactor
was then purged twice with hydrogen gas at atmospheric pressure. To
the reactor was again purged three times by pressurizing with
hydrogen to 150 psig, then venting the pressure then venting to
ambient pressure each time. The autoclave was then heated to
140.degree. C., the stirrer speed was increased to 800 rpm and the
solution was held under these conditions for 40-50 minutes. After
this, the catalyst basket was dropped in and hydrogen was then
added to bring the pressure to 1500 psig then held for 4 hours.
After 4 hours of reaction, hydrogen feed was discontinued and the
autoclave was cooled to room temperature. Agitation was then
stopped, pressure released, and the contents removed. The contents
of the final product solution were filtered using vacuum filtration
to remove any granules of the supported catalyst.
[0071] All references to NMP in the Examples are references to
99.5% anhydrous N-methyl-2-pyrrolidone (Sigma Aldrich). Except
where indicated otherwise, all references to CHDA and CHDM refer to
1,4-cyclohexanedicarboxylic acid and 1,4-cyclohexanedimethanol.
Hydrogenation of cyclohexanecarboxylic Acids to
hydroxymethylcyclohexane
[0072] For the hydrogenation of cyclohexanecarboxylic acids of
cyclohexanecarboxylic acids to hydroxymethylcyclohexanes, the 100
ml autoclave described above for the benzenecarboxylic acid
experiments was used again and the conditions were as described
below except where indicated. At atmospheric conditions, 0.25 grams
of the catalyst Ruthenium 1,1,1-tris(diphenylphosphinomethyl)ethane
(Ruthenium TRIPHOS), 2.0 grams reactant cyclohexanecarboxylic acid
and 0.02 grams p-toluene sulfonic acid (PTSA) and 30 grams of
solvent were added to the autoclave. The reactor was then
pressurized to 1500 psig with nitrogen. Nitrogen was slowly vented.
The reactor was then purged two more times by pressurizing with
nitrogen to 200 psig, then venting the pressure to atmospheric each
time. The manifold to the reactor was then purged twice with
hydrogen gas (atmospheric pressure). The reactor was then purged
three times by pressurizing with hydrogen to approximately 300
psig, then venting the pressure to atmospheric each time. Agitation
at 1000 rpm was then commenced, and hydrogen was then added to
bring the pressure to 750 psig. The temperature was then increased
to 190.degree. C. while allowing pressure to rise. After passing
185.degree. C., hydrogen pressure was increased to 1500 psig. These
conditions (190.degree. C. and 1500 psig) were held for 10 hours of
reaction. After 10 hours of reaction, the agitation was stopped and
the heat turned off to let the autoclave start cooling. After
cooling to room temperature, pressure was released and the contents
were twice pressurized with nitrogen gas and vented. The solution
was finally discharged from the autoclave and analyzed by GC, and,
in some cases, by gas chromatography--mass spectrometry
(GC-MS).
Analytical Procedures
[0073] All GC data in these examples were measured using the
following procedures. A liquid sample of 0.03 g was dissolved in
pyridine (200 .mu.l), then reacted with
N-O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) at 80.degree. C.
for 30 minutes to ensure quantitative derivatization into
corresponding trimethylsilyl derivatives. Separation and
quantification was done with a GC column and a flame ionization
detector (FID). The GC method used a DB-5 capillary column or
equivalent (30 meters.times.0.32 mm ID.times.0.25 um film
thickness), a split injector (at 330.degree. C.), a flame
ionization detector (at 300.degree. C.), helium carrier gas at a
constant linear velocity of 20.4 cm/sec (a Shimadzu GC 2010 or
equivalent) or at an initial column head pressure of 5.7 psig, an
oven temperature program of 40.degree. C. initial temperature for 6
min, and 15.degree. C/min temperature ramp to 300.degree. C. for
6.66 min final hold time. A 1-ul sample of this solution was
injected with a split ratio of 40:1. The method provided
quantification range of 0.01-100 wt. % for each analyte within its
separation capability.
[0074] Conversion percentages for the benzenecarboxylic acid
represent (moles of benzenecarboxylic acids converted divided by
initial moles of benzenecarboxylic acids) multiplied by 100. Moles
converted are determined by measuring the difference between the
number of starting moles and the number of moles at completion.
Selectivity percentages for the product cyclohexanecarboxylic acids
represent (the final moles of cyclohexanecarboxylic acid divided by
the total number of moles of benzenecarboxylic acid converted)
multiplied by 100.
[0075] CHDA conversion percentages represent (moles of CHDA
converted divided by initial moles of CHDA) multiplied by 100.
Moles converted are determined by measuring the difference between
the number of starting moles and the number of moles at completion.
CHDM selectivity percentages represent (the final moles of CHDM
divided by the total number of moles of CHDA converted) multiplied
by 100.
[0076] Mass balances in each example is (the final weight of the
solution divided by the initial weight of the solution) multiplied
by 100.
Examples 1 and 2
TPA hydrogenation to CHDA in NMP/water as a Solvent
[0077] The catalyst used was 1% Ru loaded on 1/4'' carbon granules
(1% Ru/C, Lot # SE09051, BASF Corporation, Iselin, N.J.). The
solvent in Example 1 was a mixture of 50 parts NMP and 16 parts
deionized water. The solvent in Example 2 was NMP. The filtered
resultant solution was analyzed by the GC method described above to
quantify TPA, CHDA and other byproducts. Results are presented in
Table 1 below.
TABLE-US-00001 TABLE 1 TPA hydrogenation to CHDA in the presence of
NMP as a solvent. TPA CHDA Mass Example Conversion % Selectivity %
Balance % 1 86 71 86 2 45 96.5 93
[0078] The results shown in Table 1 suggest that NMP is a suitable
solvent for highly selective production of CHDA from TPA. In the
presence of water, although the conversion increases, the
selectivity drops from 96% to 71%, the conversion increases from
45% to 86%. GC-MS was conducted for Example 2. The GC wt. %
accountability for Example 2 was 101.4% and the cis/trans ratio of
product CHDA was 4.4.
Comparative Examples 1-8
[0079] The effect of using other solvents on TPA hydrogenation to
CHDA were considered. The procedures of Example 2 were repeated
using other liquids with published TPA solubilities greater or less
than that of NMP. Results (along with published solubility data,
presented in grams of TPA per grams of solvent at 25.degree. C.)
are provided in Table 2, along with the results from Examples 1 and
2.
TABLE-US-00002 TABLE 2 TPA hydrogenation to CHDA in the presence of
other solvents. Published TPA Solubility In Solvent TPA CHDA Mass
Example Solvent g/100 g at 25.degree. C. Conversion % Selectivity %
Balance % 1 50 parts NMP and 86 71 86 16 parts deionized water 2
NMP 5.5.sup.a 45 96.5 93 ~5.sup.b Comp 1 Dimethyl sulfoxide
20.sup.c 7 5 96 (DMSO) Comp 2 Methanol** 0.1.sup.c 60* 17* 63 Comp
3 1,3-Dimethyl-2- 69 16 94 imidazolidinone Comp 4 1,3-Dimethyl- 4 7
94 3,4,5,6-tetrahydro 2(1H)-pyrimidinone Comp 5 5-Ethyl-2- 15 0 94
methylpyridine Comp 6 Dimethylformamide 6.7.sup.c 95 4 100 (DMF)
7.4.sup.d Comp 7 N,N- ~3.sup.b 67 45 92 Dimethylacetamide (DMAC)
Comp 8 Water** 0.0019.sup.c 16 20 88 *GC-MS results indicate that
the other species accounting for the conversion of TPA are the
mono-methylester and di-methylester of TPA. **Due to the formation
of bi-phasic products, the conversions are based also on the weight
of the solid TPA obtained. .sup.aLi, D. Q., et al., "Solubilities
of Terephthalaldehydic, p-Toluic, Benzoic, Terephthalic, and
Isophthalic Acids in N-Methyl-2-pyrrolidone from 295.65 K to 371.35
K". Chem Eng. Data 46, 172. (2001). .sup.bU.S. Pat. No. 6,113,866
.sup.cPublished data contained in catalog of design theses at
http://www.sbioinformatics.com/design_thesis/Terephthalic_acid/Terephthal-
ic-2520acid_Properties&uses.pdf .sup.dHarper, J. J. and Janik,
P., "Terephthalic Acid Solubility" J. Chem Eng. Data 15, 439.
(1970).
[0080] These data demonstrate that use of even some solvents having
higher published solubility than that of NMP resulted in lower
yields of CHDA and in some cases, no evidence of catalytic
hydrogenation activity was observed.
Example 3
TPA hydrogenation to CHDA in NEP as a Solvent.
[0081] Example 2 was repeated but instead of N-methyl 2-pyrrolidone
(NMP) as a solvent, N-ethyl 2-pyrrolidone (NEP) was used as a
solvent. The GC wt. % accountability for Example 4 was 91.3% and
the cis/trans ratio of product CHDA was 4.6.
TABLE-US-00003 TABLE 3 TPA hydrogenation to CHDA in the presence of
NEP as a solvent. TPA CHDA Mass Example Solvent Conversion %
Selectivity % Balance % 3 NEP 71.6 82.3 95
[0082] As can be seen from the result in Table 3, NEP is a suitable
solvent for TPA hydrogenation to CHDA much like NMP.
Examples 4 and 5
Higher Volume Experiments.
[0083] The experiments were conducted using the Ruthenium on carbon
catalyst in a 1000 ml autoclave. A 300 ml autoclave configured in a
high pressure AUTO-MATE System Model 4560 (H.E.L. Inc., Grand
Rapids, MI). These reactions used nine grams of terephthalic acid
and 200 grams of a 3:1 mixture of NMP and water. The amount of
ruthenium on carbon catalyst was 20 grams in Example 4 and ten
grams in Example 5. Procedures were otherwise consistent with
Example 2. TPA conversion and CHDA selectivity data are presented
in Table 4.
TABLE-US-00004 TABLE 4 TPA hydrogenation to CHDA in the presence of
NMP as a solvent. Example TPA Conversion % CHDA Selectivity % 4 100
81 5 100 90
[0084] As seen in Table 4, the catalyst activity is appreciable
with 100% conversion of TPA and 90% selectivity to CHDA giving a
total yield of 90%.
Comparative Examples 9-10
[0085] The procedures of Example 2 were repeated with the following
exceptions. Comparative Example 9 was conducted in the absence of
hydrogen. The autoclave was pressurized instead with 1500 psig
nitrogen instead. Comparative Example 10 was conducted in the
absence of the Ru/C catalyst but in the presence of 1500 psig
hydrogen. The resulting product solutions were analyzed by GC-MS.
In both these experiments, no CHDA was obtained from TPA.
Example 6
IPA hydrogenation to 1,3-CHDA in NMP.
[0086] The procedures of Example 2 were repeated except that
terephthalic acid was replaced with isophthalic acid (IPA) and the
resulting CHDA was 1,3 cyclohexanedicarboxylic acid. Results are
presented in Table 5. Attractive conversion and selectivity were
achieved.
TABLE-US-00005 TABLE 5 IPA hydrogenation to CHDA in the presence of
NMP as a solvent. Example IPA Conversion % CHDA Selectivity % 6 66
93
Examples 7-11
TPA hydrogenation to CHDA in NMP as a Solvent with other Noble
metals as Catalysts
[0087] The procedures of Example 2 were repeated replacing the
ruthenium on carbon with other supported noble metal catalysts. The
reaction parameters are detailed below in Table 6.
[0088] For the Rhodium catalyst in Examples 10 and 11, a lower
temperature and pressure were used. Use of the Rh/C catalyst with
NMP as a solvent resulted in 88% conversion of TPA and 97%
selectivity to CHDA at only 500 psig H.sub.2 pressure and
100.degree. C. temperature. GC-MS for Example 10 was conducted. The
GC wt. % accountability or Example 10 was 100.6% and the cis/trans
ratio of product CHDA was 4.7. The GC wt. % accountability for
Example 11 was 100% and the cis/trans ratio of product CHDA was
4.0.
TABLE-US-00006 TABLE 6 TPA hydrogenation to CHDA in the presence of
NMP as a solvent with different catalysts. Pressure Temperature TPA
CHDA Mass Example Catalyst psig .degree. C. Conversion %
Selectivity % Balance % 7 Pd/C* 1500 140 7.2 5.5 92 8 Pt/C** 1500
140 15.2 19.3 95 9 Ir/C*** 1500 140 16.3 0 96 10 Rh/C**** 500 100
88.5 97 94 11 Rh/C**** 1000 100 47.3 97.2 96 *0.5% Pd/C, CBA300,
Lot # SE09101, BASF Corporation, Iselin, NJ, 08830 **5% Pt/C,
Sample Code 43220, Lot # 08860, BASF Italia, Rome Italy. ***1%
Ir/C, 38330, Lot # E22Y009, Alfa Aesar - A Johnson Matthey Company,
Ward Hill, MA, ****5% Rh/C, SO 20337, Lot # 31005, BASF
Corporation, Iselin, NJ, 08830
[0089] The use of Rh/C catalysts in the presence of NMP as a
solvent affords the possibility of running the hydrogenation at
lower temperatures and pressures.
Example 12
Increased Concentration TPA Hydrogenation to CHDA in the Presence
of NMP as a Solvent.
[0090] Experimental conditions from Example 10 were followed except
that instead of only 3 g TPA in 50 g NMP, 6 g TPA was charged to
the reactor. Even at this increased concentration of TPA, the final
product was a single solution of TPA, CHDA in NMP with no formation
of solids. Results are presented in Table 7. GC-MS was conducted.
The GC wt. % accountability was 101.2% and the cis/trans ratio of
product CHDA was 4.5. The high solubility of TPA in NMP affords the
possibility of higher production rates by increasing the
concentration of TPA.
TABLE-US-00007 TABLE 7 Increased concentration TPA hydrogenation to
CHDA in the presence of NMP as a solvent. TPA CHDA Mass Example
Solvent Conversion % Selectivity % Balance % 12 NMP 77.9 95 93
Examples 13-14
Enhanced TPA hydrogenation to CHDA in NMP and Isopropanol as a
Solvent
[0091] The procedures of Example 10 were repeated but the amount of
TPA charged to the reactor was 2.75 grams the hydrogen pressure was
200 psig and the reaction was discontinued after 2 hours at 200
psig hydrogen pressure. The solvent in Example 13 was NMP and the
solvent in Example 14 was a 9:1 mixture of NMP with isopropanol
(anhydrous 99.5% Sigma Aldrich). Results are presented in Table 8
below. As can be seen, although the reaction conditions in Example
13 reduced the TPA conversion, the addition of isopropanol in
Example 14 doubled the conversion of TPA with no change in the
selectivity to CHDA. The GC wt. % accountability for Examples 13
and 14 were 98.4% and 96.9%, respectively, whereas the cis/trans
ratios of product CHDA were 4.8 and 5.4, respectively.
TABLE-US-00008 TABLE 8 TPA hydrogenation to CHDA in the presence of
NMP/isopropanol as a solvent with Rh/C. TPA CHDA Mass Example
Solvent Conversion % Selectivity % Balance % 13 NMP 40.8 92.8 93 14
90% NMP + 88.5 93.1 93 10% Isopropanol
Example 15
Low Pressure TPA hydrogenation to CHDA with Ru/C Catalyst
[0092] The procedures of Example 13 were repeated, but instead of a
Rh/C catalyst the Ru/C catalyst of Example 2 was used. Results are
presented in Table 9, rhodium catalyst achieves higher CHDA
selectivity and TPA conversion rates under these conditions than
the ruthenium.
TABLE-US-00009 TABLE 9 TPA hydrogenation to CHDA in the presence of
NMP as a solvent with Ru/C. TPA CHDA Mass Example Solvent
Conversion % Selectivity % Balance % 15 NMP 11.5 14.8 93
Comparative Examples 11-12
Attempted TPA hydrogenation to CHDA with other Solvents on a Rh/C
Catalyst
[0093] These examples illustrate that the different influence of
NMP and DMSO as solvents on the activity of ruthenium catalysts is
also observed for rhodium catalysts. The procedures of Example 13
were repeated using either DMSO (Comparative Example 11) or DMAC
(Comparative Example 12) instead of NMP. No formation of CHDA was
observed in Comparative Example 11. With the use of DMAC as a
solvent in Comparative Example 12, only 4.8% CHDA was observed.
[0094] Example 16-17
Low pressure benzoic acid hydrogenation in NMP as a Solvent with
Rh/C Catalyst
[0095] To demonstrate the applicability of the invention to other
benzenecarboxylic acid, experiments were conducted involving the
selective ring hydrogenation of benzoic acid (BA) to
cyclohexanecarboxylic acid (CHCA). The procedures of Example 2 were
repeated, but modified as shown in Table 10 below, and with the
same amount of benzoic acid in the place of TPA. Results are also
presented in Table 10. The GC wt. % accountability for Examples 16
and 17 were 97% and 94%, respectively.
TABLE-US-00010 TABLE 10 Benzoic acid hydrogenation in the presence
of NMP as a solvent with a Rh/C catalyst. BA CHCA Pressure
Temperature Conversion Selectivity Mass Example Psig .degree. C. %
% Balance % 16 100 100 99.6 93 94 17 500 100 99.6 90 94
Examples 18-20
Resistance of CHDA to hydrogenation in Catalyst Systems
[0096] These following examples were completed to illustrate the
stability of CHDA formed in the processes of the present invention.
For Examples 18 and 19, the procedures of Example 2 and Comparative
Example 1, respectively, were repeated except that CHDA rather than
TPA was fed to the reactors. For Example 20, the procedures of
Example 13 were repeated except that CHDA rather than TPA was fed
to the reactor, the reaction pressure was 200 psig and the reaction
time was two hours. The results, presented in Table 11, indicate
low levels of CHDA conversion and no detectable formation of CHDM.
The cis/trans ratio of CHDA in all three examples were measured at
3.5 both before and after the reaction, indicating no hydrogenation
or isomerization of CHDA occurred.
TABLE-US-00011 TABLE 11 Attempted CHDA hydrogenation to CHDM in NMP
as a solvent with 1 wt. % Ru/C catalyst (Examples 18 and 19) and
with a Rh/C catalyst (Example 20). Example Solvent CHDA Conversion
% CHDM Formed 18 NMP 5.7 No 19 DMSO 7.2 No 20 NMP 2.9 No
Examples 21-22
CHDA hydrogenation to CHDM in NMP and NMP Blend.
[0097] The above procedures for hydrogenation of
cyclohexanecarboxylic acids to hydroxymethylcyclohexanes were
followed. The catalyst used was Ruthenium TRIPHOS and the reactant
was CHDA. Results are presented in Table 12 below.
TABLE-US-00012 TABLE 12 CHDA hydrogenation to CHDM in the presence
of NMP as a solvent. CHDM Cis/ Selectivity Trans Example Reactant
Solvent Conversion % % Ratio 21 CHDA NMP - 30 g 95.6 59.7 0.99 22
CHDA NMP - 30 g 86.6 43.2 0.7 Water - 3 g
[0098] Lower selectivity was observed in Example 22. To understand
if the Ruthenium TRIPHOS catalyst was capable of generating
products from hydrogenolysis, a GC-MS scan was taken of the product
solution. GC-MS results indicated that the catalyst did not convert
CHDM to alkanes. The only other byproduct observed in the GC-MS
scan was the partially hydrogenated product
4-(hydroxymethyl)cyclohexanecarboxylic acid.
Example 23
CHDA hydrogenation to CHDM in ethanol as a Solvent
[0099] Example 23 repeated the procedures of Example 21 except that
the solvent was ethanol. Results are presented in Table 13 below.
The conversions are based on moles of the reactant
cyclohexanediacid converted to initial moles of the reactant. The
selectivities are based on the final moles of CHDM relative to the
reacted moles of the reactant. GC-MS indicated that the other major
product is 4-(hydroxymethyl)cyclohexanecarboxylic acid.
Decarbonylated products were not observed.
TABLE-US-00013 TABLE 13 CHDA hydrogenation to CHDM in the presence
of ethanol as a solvent. CHDM Example Reactant Conversion %
Selectivity % Cis/Trans Ratio 23 CHDA 99.2 97.4 1.21
* * * * *
References