METHOD AND CATALYST SYSTEM FOR PRODUCING
AROMATIC CARBONATES
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a method and catalyst system for producing
aromatic carbonates and, more specifically, to a method and catalyst system for
producing diaryl carbonates through the carbonylation of aromatic hydroxy
compounds.
2. Discussion of Related Art:
Aromatic carbonates find utility, inter alia, as intermediates in the preparation of
polycarbonates. For example, a popular method of polycarbonate preparation is the
melt transesterification of aromatic carbonates with bisphenols. This method has been
shown to be environmentally superior to previously used methods which employed
phosgene, a toxic gas, as a reagent and chlorinated aliphatic hydrocarbons, such as
methylene chloride, as solvents.
Various methods for preparing aromatic carbonates have been previously described in
the literature and/or utilized by industry. A method that has enjoyed substantial
popularity in the literature involves the direct carbonylation of aromatic hydroxy
compounds with carbon monoxide and oxygen. In general, practitioners have found
that the carbonylation reaction requires a rather complex catalyst system. For
example, in U.S. Patent No. 4,187,242, which is assigned to the assignee of the
present invention. Chalk reports that a carbonylation catalyst system should contain a
Group VIII B metal, such as ruthenium, rhodium, palladium, osmium, iridium,
platinum, or a complex thereof. Further refinements to the carbonylation reaction
include the identification of organic co-catalysts, such as terpyridines,
phenanthrolines, quinolines and isoquinolines in U.S. Patent No. 5,284,964 and the
use of certain halide compounds, such as quaternary ammonium or phosphonium
halides in U.S. Patent No. 5,399,734, both patents also being assigned to the assignee
of the present invention.
The economics of the carbonylation process is strongly dependent on the
number of moles of aromatic carbonate produced per mole of Group VIII B metal
utilized (i.e. "catalyst turnover"). Consequently, much work has been directed to the
identification of efficacious inorganic co-catalysts that increase catalyst turnover. In
U.S. Patent No. 5,231,210, which is also assigned to General Electric Company,
Joyce et al. report the use of a cobalt pentadentate complex as an inorganic co-catalyst
("lOCC"). In U.S. Patent No. 5,498,789, Takagi et al. report the use of lead as an
lOCC. In U.S. Patent No. 5,543,547, Iwane et al. report the use of trivalent cerium as
an lOCC. In U.S. Patent No. 5,726,340, Takagi et al. report the use of lead and cobalt
as a binary lOCC system. In Japanese Unexamined Patent Application No. 10-
316627, Yoneyama et al. report the use of manganese and the combination of
manganese and lead as lOCC's.
The literature is silent, however, as to the role of the lOCC in the carbonylation
reaction (i.e. the reaction mechanism). Accordingly, meaningfiil guidance regarding
the identification of additional lOCC systems is cursory at best. Periodic table
groupings have failed to provide guidance in identifying additional lOCC's. For
example, U.S. Patent No. 5,856,554 provides a general listing of possible lOCC
candidates, yet further analysis has revealed that many of the members (and
combinations of members) of the recited groups (i.e.. Groups IV B and V B) do not
catalyze the carbonylation reaction. Therefore, due to the lack of guidance in the
literature, the identification of effective carbonylation catalyst systems has become a
serendipitous exercise.
As the demand for high performance plastics has continued to grow, new and
improved methods of providing product more economically are needed to supply the
market. In this context, various processes and catalyst systems are constantly being
evaluated; however, the identities of improved and/or additional effective catalyst
systems for these processes continue to elude the industry. Consequently, a long felt,
yet unsatisfied need exists for new and improved methods and catalyst systems for
producing aromatic carbonates and the like.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method and catalyst system for
producing aromatic carbonates. In one embodiment, the present invention provides a
method of carbonylating aromatic hydroxy compounds by contacting at least one
aromatic hydroxy compound with oxygen and carbon monoxide in the presence of a
carbonylation catalyst system that includes a catalytic amount of an inorganic co-
catalyst containing zinc.
In various alternative embodiments, the carbonylation catalyst system can
include an effective amount of a palladium source and an effective amount of a halide
composition. Further alternative embodiments can include catalytic amounts of
various co-catalyst combinations, such as zinc and copper; zinc, copper, and titanium;
zinc, copper and iron; zinc and cerium; zinc and manganese; zinc, manganese, and
europium; zinc, manganese, and bismuth; zinc and europium; zinc and nickel; zinc
and iron; zinc and cobalt; zinc and ruthenium; zinc and rhodium; zinc and zirconium;
and zinc and chromium.
BRIEF DESCRIPTION OF THE DRAWING
Various features, aspects, and advantages of the present invention will become
more apparent with reference to the following description, appended claims, and
accompanying drawing, wherein the FIGURE is a schematic view of a device capable
of performing an aspect of an embodiment of the present invention.
DETAILED DESCRIPTION
The present invention is directed to a method and catalyst system for producing
aromatic carbonates. In one embodiment, the method includes the step of contacting
at least one aromatic hydroxy compound with oxygen and carbon monoxide in the
presence of a carbonylation catalyst system that includes a catalytic amount of an
inorganic co-catalyst containing zinc. In alternative embodiments, the catalyst system
can include an effective amount of a Group VIII B metal and an effective amount of a
halide composition.
Unless otherwise noted, the term "effective amount," as used herein, includes that
amount of a substance capable of either increasing (directly or indirectly) the yield of
the carbonylation product or increasing selectivity toward an aromatic carbonate.
Optimum amounts of a given reactant can vary based on reaction conditions and the
identity of other constituents yet can be readily determined in light of the discrete
circumstances of a given application.
Aromatic hydroxy compounds which may be used in the practice of the present
invention include aromatic mono or polyhydroxy compounds, such as phenol, cresol,
xylenol, resorcinol, hydroquinone, and bisphenol A. Aromatic organic mono hydroxy
compounds are preferred, with phenol being more preferred.
In various preferred embodiments, the carbonylation catalyst system can contain at
least one constituent from the Group VIII B metals or a compound thereof. A
preferred Group VIII B constituent is an effective amount of a palladium source. In
various embodiments, the palladium source may be in elemental form, or it may be
employed as a palladium compound. Accordingly, palladium black or elemental
palladium deposited on carbon may be used as well as palladium halides, nitrates,
carboxylates, oxides and palladium complexes containing carbon monoxide, amines,
phosphines or olefins. As used herein, the term "complexes" includes coordination or
complex compounds containing a central ion or atom. The complexes may be
nonionic, cationic, or anionic, depending on the charges carried by the central atom
and the coordinated groups. Other common names for these complexes include
complex ions (if electrically charged), Werner complexes, and coordination
complexes.
In various applications, it may be preferable to utilize palladium(II) salts of organic
acids, including carboxylates with C2_6 aliphatic acids. Palladium(II) acetylacetonate
is also a suitable palladium source. Preferably, the amount of Group VIII B metal
source employed should be sufficient to provide about 1 mole of metal per 800-
10,000 moles of aromatic hydroxy compound. More preferably, the proportion of
Group VIII B metal source employed should be sufficient to provide about 1 mole of
metal per 2,000-5,000 moles of aromatic hydroxy compound.
The carbonylation catalyst system may fiirther contain an effective amount of a halide
composition, such as an organic halide salt. In various preferred embodiments, the
halide composition can be an organic bromide salt. The salt may be a quaternary
ammonium or phosphonium salt, or a hexaalkylguanidinium bromide. In various
embodiments, a, co-bis(pentaalkylguanidinium)alkane salts may be preferred. Suitable
organic halide compositions include tetrabutylammonium bromide,
tetraethylammonium bromide, and hexaethylguanidinium bromide. In preferred
embodiments, the carbonylation catalyst system can contain between about 5 and
about 1000 moles of bromide per mole of palladium employed, and, more preferably,
between about 50 and about 150 molar equivalents of bromide are used.
The formation of diaryl carbonates in a carbonylation reaction can be accompanied by
the formation of by-products, such as bisphenols, in varying proportions. In order to
increase selectivity to diaryl carbonate, various organic co-catalysts may be
incorporated in the carbonylation catalyst system. Depending on the application,
suitable organic co-catalyst may include various phosphine, quinone, terpyridine,
phenanthroline, quinoline and isoquinoline compounds and their derivatives, such as
2,2':6',2-terpyridine, 4'-methylthio-2,2':6',2-terpyridine, 2,2':6',2-terpyridine N-
oxide, 1,10-phenanthroline, 2,4,7,8-tetramethyl-l,10-phenanthroline, 4,7-diphenyl-
1,10-phenanthroline and 3,4,7,8-tetramethyl-1,10-phenanthroline.
The carbonylation catalyst system includes a catalytic amount of an inorganic co-
catalyst (lOCC) containing zinc. In addition to zinc per se, it has been discovered that
certain lOCC combinations can effectively catalyze the carbonylation reaction. Such
lOCC combinations include zinc and copper; zinc, copper, and titanium; zinc, copper
and iron; zinc and cerium; zinc and manganese; zinc, manganese, and europium; zinc,
manganese, and bismuth; zinc and europium; zinc and nickel; zinc and iron; zinc and
cobalt; zinc and ruthenium; zinc and rhodium; zinc and zirconium; and zinc and
chromium.
An lOCC can be introduced to the carbonylation reaction in various forms, including
salts and complexes, such as tetradentate, pentadentate, hexadentate, or octadentate
complexes. Illustrative forms may include oxides, halides, carboxylates, diketones
(including beta-diketones), nitrates, complexes containing carbon monoxide or
olefins, and the like. Suitable beta-diketones include those known in the art as ligands
for the lOCC metals of the present invention. Examples include, but are not limited
to, acetylacetone, benzoylacetone, dibenzoylmethane, diisobutyrylmethane, 2,2-
dimethylheptane-3,5-dione, 2,2,6-trimethylheptane-3,5-dione, dipivaloylmethane, and
tetramethylheptanedione. The quantity of ligand is preferably not such that it
interferes with the carbonylation reaction itself, with the isolation or purification of
the product mixture, or with the recovery and reuse of catalyst components (such as
palladium). An lOCC may be used in its elemental form if sufficient reactive surface
area can be provided. In embodiments employing supported palladium, it is noted
that the zinc-based lOCC provides a discrete, catalytic source of zinc in a form
favorable for such catalysis.
lOCC's are included in the carbonylation catalyst system in catalytic amounts. In this
context a "catalytic amount" is an amount of lOCC (or combination of lOCC's) that
increases the number of moles of aromatic carbonate produced per mole of Group
VIII B metal utilized; increases the number of moles of aromatic carbonate produced
per mole of halide utilized; or increases selectivity toward aromatic carbonate
production beyond that obtained in the absence of the lOCC (or combination of
lOCC's). Optimum amounts of an lOCC in a given application will depend on various
factors, such as the identity of reactants and reaction conditions. For example, when
palladium is included in the reaction, the molar ratio of zinc relative to palladium at
the initiation of the reaction is preferably between about 0.1 and about 100.
Additional lOCC's may be used in the carbonylation catalyst system, provided the
additional lOCC does not deactivate (i.e. "poison") the original lOCC. Examples of
additional lOCC's may include lead and/or iridium.
The carbonylation reaction can be carried out in a batch reactor or a
continuous reactor system. Due in part to the low solubility of carbon monoxide in
organic hydroxy compounds, such as phenol, it is preferable that the reactor vessel be
pressurized. In preferred embodiments, gas can be supplied to the reactor vessel in
proportions of between about 2 and about 50 mole percent oxygen, with the balance
being carbon monoxide. Additional gases may be present in amounts that do not
deleteriously affect the carbonylation reaction. The gases may be introduced
separately or as a mixture. A total pressure in the range of between about 10 and
about 250 atmospheres is preferred. Drying agents, typically molecular sieves, may be
present in the reaction vessel. Reaction temperatures in the range of between about
60° C and about 150° C are preferred. Gas sparging or mixing can be used to aid the
reaction.
In order that those skilled in the art will be better able to practice the present invention
reference is made to the FIGURE, which shows an example of a continuous reactor
system for producing aromatic carbonates. The symbol "V" indicates a valve and the
symbol "P" indicates a pressure gauge.
The system includes a carbon monoxide gas inlet 10, an oxygen inlet 11, a manifold
vent 12, and an inlet 13 for a gas, such as carbon dioxide. A reaction mixture can be
fed into a low pressure reservoir 20, or a high pressure reservoir 21, which can be
operated at a higher pressure than the reactor for the duration of the reaction. The
system further includes a reservoir outlet 22 and a reservoir inlet 23. The gas feed
pressure can be adjusted to a value greater than the desired reactor pressure with a
pressure regulator 30. The gas can be purified in a scrubber 31 and then fed into a
mass flow controller 32 to regulate flow rates. The reactor feed gas can be heated in a
heat exchanger 33 having appropriate conduit prior to being introduced to a reaction
vessel 40. The reaction vessel pressure can be controlled by a back pressure regulator
41. After passing through a condenser 25, the reactor gas effluent may be either
sampled for further analysis at valve 42 or vented to the atmosphere at valve 50. The
reactor liquid can be sampled at valve 43. An additional valve 44 can provide further
system control, but is typically closed during the gas flow reaction.
In the practice of one embodiment of the invention, the carbonylation catalyst system
and aromatic hydroxy compound are charged to the reactor system. The system is
sealed. Carbon monoxide and oxygen are introduced into an appropriate reservoir
until a preferred pressure (as previously defined) is achieved. Circulation of condenser
water is initiated, and the temperature of the heat exchanger 33 (e.g., oil bath) can be
raised to a desired operating temperature. A conduit 46 between heat exchanger 33
and reaction vessel 40 can be heated to maintain the desired operating temperature.
The pressure in reaction vessel 40 can be controlled by the combination of reducing
pressure regulator 30 and back pressure regulator 41. Upon reaching the desired
reactor temperature, aliquots can be taken to monitor the reaction.
EXAMPLES
The following examples are included to provide additional guidance to those skilled
in the art in practicing the claimed invention. While some of the examples are
illustrative of various embodiments of the claimed invention, others are comparative
and are identified as such. The examples provided are merely representative of the
work that contributes to the teaching of the present application. Accordingly, these
examples are not intended to limit the invention, as defined in the appended claims, in
any manner. Unless otherwise specified, all parts are by weight, and all equivalents
are relative to palladium. Reaction products were verified by gas chromatography. All
reactions were carried out in a glass, batch reactor at 90-100° C in a 10% O2 in CO
atmosphere at an operating pressure of 95-102 atm. Reaction time was generally 2-3
hours.
As discussed supra, the economics of aromatic carbonate production is dependent on
the number of moles of aromatic carbonate produced per mole of Group VIII B metal
utilized. In the following examples, the aromatic carbonate produced is
diphenylcarbonate (DPC) and the Group VIII B metal utilized is palladium. For
convenience, the number of moles of DPC produced per mole of palladium utilized is
referred to as the palladium turnover number (Pd TON).
BASELINE EXAMPLE
In order to determine the comparative efficacy of various embodiments of the
present invention, baseline data were produced by adding, at ambient conditions, 0.25
mM palladium(II) acetylacetonate and various amounts of halide compositions to a
glass reaction vessel containing phenol. The reactants were heated to 100°C for 3
hours in a 10 % oxygen in carbon monoxide atmosphere. After the reaction, samples
were analyzed for DPC by gas chromatography producing the following results:
EXAMPLE 1
Diphenyl carbonate was produced by adding, at ambient conditions, palladium(II)
acetylacetonate, hexaethylguanidinium bromide ("HegBr"), and zinc(II)
acetylacetonate as an inorganic co-catalyst to a glass reaction vessel containing
phenol. The reactants were heated to 100°C for 3 hours in a 10 % oxygen in carbon
monoxide atmosphere. After the reaction, samples were analyzed for DPC by gas
chromatography. The following results were observed:
The procedure was repeated with various zinc complexes using various bromide
amounts to produce the following results:
The various reaction conditions show that a Pd TON at least as high as 683 can be
obtained utilizing zinc as an lOCC. Based on the results of these experiments, it is
evident that an lOCC containing zinc can effectively catalyze the carbonylation
reaction.
EXAMPLE 2
The general procedure of Example 1 was repeated with 25 ppm palladium(II)
acetylacetonate, 123 equivalents of bromide in the form of tetraethylammonium
bromide, and the following lOCC combination: 11 equivalents of zinc in the form of
zinc(II) acetylacetonate and 9 equivalents of copper in the form of copper(II)
acetylacetonate. The Pd TON was found to be 1219, thus showing that the lOCC
combination of zinc and copper can effectively catalyze the carbonylation reaction.
EXAMPLE 3
The general procedure of Examples 1 and 2 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate, 14 equivalents of copper in the form- of copper(II)
acetylacetonate, and 14 equivalents of titanium in the form of titanium(IV) oxide
acetylacetonate. The Pd TON was found to be 1145, thus showing that the lOCC
combination of zinc, copper, and titanium can effectively catalyze the carbonylation
reaction.
EXAMPLE 4
The general procedure of Examples 1-3 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate, 14 equivalents of copper in the form of copper(II)
acetylacetonate, and 14 equivalents of iron in the form of iron(III) acetylacetonate.
The Pd TON was found to be 1141, thus showing that the lOCC combination of zinc,
copper, and iron can effectively catalyze the carbonylation reaction.
EXAMPLE 5
The general procedure of Examples 1-4 was repeated with 25 ppm palladium(II)
acetylacetonate, 123 equivalents of bromide in the form of tetraethylammonium
bromide, and the following lOCC combination: 11 equivalents of zinc in the form of
zinc(II) acetylacetonate and 9 equivalents of cerium in the form of cerium(III)
acetylacetonate. The Pd TON was found to be 1284, thus showing that the lOCC
combination of zinc and cerium can effectively catalyze the carbonylation reaction.
EXAMPLE 6
The general procedure of Examples 1-5 was repeated with 25 ppm palladium(II)
acetylacetonate, 123 equivalents of bromide in the form of tetraethylammonium
bromide, and the following lOCC combination: 11 equivalents of zinc in the form of
zinc(II) acetylacetonate and 10 equivalents of manganese in the form of
manganese(II) acetylacetonate. The Pd TON was found to be 1876, thus showing that
the lOCC combination of zinc and manganese can effectively catalyze the
carbonylation reaction.
EXAMPLE 7
The general procedure of Examples 1-6 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate, 14 equivalents of manganese in the form of manganese(III)
acetylacetonate, and 14 equivalents of europium in the form of europium(III)
acetylacetonate. The Pd TON was found to be 782, thus showing that the lOCC
combination of zinc, manganese, and europium can effectively catalyze the
carbonylation reaction.
EXAMPLE 8
The general procedure of Examples 1-7 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate, 14 equivalents of manganese in the form of manganese(III)
acetylacetonate, and 14 equivalents of bismuth in the form of
bismuth(II)tetramethylheptanedionate. The Pd TON was found to be 452, thus
showing that the lOCC combination of zinc, manganese, and bismuth can effectively
catalyze the carbonylation reaction.
EXAMPLE 9
The general procedure of Examples 1-8 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate and 14 equivalents of europium in the form of europium(III)
acetylacetonate. The Pd TON was found to be 448, thus showing that the lOCC
combination of zinc and europium can effectively catalyze the carbonylation reaction.
EXAMPLE 10
The general procedure of Examples 1-9 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate and 14 equivalents of nickel in the form of nickel(II)
acetylacetonate. The Pd TON was found to be 298, thus showing that the lOCC
combination of zinc and nickel can effectively catalyze the carbonylation reaction.
The experiment was repeated with 25 ppm palladium(II) acetylacetonate, 123
equivalents of bromide in the form of tetraethylammonium bromide, and the
following lOCC combination: 11 equivalents of zinc in the form of zinc(II)
acetylacetonate and 11 equivalents of nickel in the form of nickel(II) acetylacetonate.
The Pd TON was found to be 1017.
EXAMPLE 11
The general procedure of Examples 1-10 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate and 14 equivalents of chromium in the form of chromium(III)
acetylacetonate. The Pd TON was found to be 401, thus showing that the lOCC
combination of zinc and chromium can effectively catalyze the carbonylation
reaction.
The experiment was repeated with 25 ppm palladium(II) acetylacetonate, 123
equivalents of bromide in the form of tetraethylammonium bromide, and the
following lOCC combination: 11 equivalents of zinc in the form of zinc(II)
acetylacetonate and 8 equivalents of chromium in the form of chromium(III)
acetylacetonate. The Pd TON was found to be 674.
EXAMPLE 12
The general procedure of Examples 1-11 was repeated with 25 ppm palladium(II)
acetylacetonate, 123 equivalents of bromide in the form of tetraethylammonium
bromide, and the following lOCC combination: 11 equivalents of zinc in the form of
zinc(II) acetylacetonate and 9 equivalents of iron in the form of iron(III)
acetylacetonate. The Pd TON was found to be 969, thus showing that the lOCC
combination of zinc and iron can effectively catalyze the carbonylation reaction.
EXAMPLE 13
The general procedure of Examples 1-12 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate and 14 equivalents of cobalt in the form of cobalt(III)
acetylacetonate. The Pd TON was found to be 205, thus showing that the lOCC
combination of zinc and cobalt can effectively catalyze the carbonylation reaction.
EXAMPLE 14
The general procedure of Examples 1-13 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate and 14 equivalents of ruthenium in the form of ruthenium(III)
acetylacetonate. The Pd TON was found to be 367, thus showing that the lOCC
combination of zinc and ruthenium can effectively catalyze the carbonylation
reaction.
EXAMPLE 15
The general procedure of Examples 1-14 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate and 14 equivalents of rhodium in the form of rhodium(III)
acetylacetonate. The Pd TON was found to be 488, thus showing that the lOCC
combination of zinc and rhodium can effectively catalyze the carbonylation reaction.
EXAMPLE 16
The general procedure of Examples 1-15 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate and 14 equivalents of zirconium in the form of zirconium(lV)
acetylacetonate. The Pd TON was found to be 167, thus showing that the lOCC
combination of zinc and zirconium can effectively catalyze the carbonylation
reaction.
COMPARATIVE EXAMPLE A
It has been determined that several potential lOCC candidates do not catalyze
the carbonylation reaction and in fact may poison an otherwise effective lOCC
combination. For example, the general procedure of Examples 1-16 was repeated with
25 ppm palladium(II) acetylacetonate, 60 equivalents of bromide in the form of
hexaethylguanidinium bromide, and 14 equivalents of antimony in the form of
antimony(III)bromide as a potential lOCC candidate. The Pd TON was found to be
zero, thereby showing that Sb(III) does not effectively catalyze the carbonylation
reaction at the conditions used.
COMPARATIVE EXAMPLE B
The general procedure of Examples 1-16 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and the following lOCC combination: 14 equivalents of zinc in the form of
zinc(II) acetylacetonate and 14 equivalents of antimony in the form of SbBrs. The Pd
TON was found to be zero, thereby showing that, in addition to failing to effectively
catalyze the carbonylation reaction as a sole lOCC, Sb(III) can poison an otherwise
effective lOCC (i.e. zinc) at the conditions used.
COMPARATIVE EXAMPLE C
The general procedure of Examples 1-16 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and 14 equivalents of vanadium in the form of vanadium(III)
acetylacetonate as a potential lOCC candidate. The Pd TON was found to be zero,
thereby showing that V(III) does not effectively catalyze the carbonylation reaction at
the conditions used.
COMPARATIVE EXAMPLE D
The general procedure of Examples 1-16 was repeated with 25 ppm palladium(II)
acetylacetonate, 60 equivalents of bromide in the form of hexaethylguanidinium
bromide, and 14 equivalents of vanadium in the form of vanadium(IV) oxide
acetylacetonate as a potential lOCC candidate. The Pd TON was found to be zero,
thereby showing that V(IV) does not effectively catalyze the carbonylation reaction at
the conditions used.
It will be understood that each of the elements described above, or two or more
together, may also find utility in applications differing from the types described
herein. While the invention has been illustrated and described as embodied in a
method and catalyst system for producing aromatic carbonates, it is not intended to be
limited to the details shown, since various modifications and substitutions can be
made without departing in any way from the spirit of the present invention. For
example, additional effective lOCC compounds can be added to the reaction. As such,
further modifications and equivalents of the invention herein disclosed may occur to
persons skilled in the art using no more than routine experimentation, and all such
modifications and equivalents are believed to be within the spirit and scope of the
invention as defined by the following claims.
CLAIMS
What is claimed is:
1. A carbonylation catalyst system, comprising a catalytic amount of an
inorganic co-catalyst comprising zinc.
2. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and copper.
3. The carbonylation catalyst system of claim 2, wherein the combination of
inorganic co-catalysts ftxrther comprises titanium.
4. The carbonylation catalyst system of claim 2, wherein the combination of
inorganic co-catalysts further comprises iron.
5. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and cerium.
6. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and manganese.
7. The carbonylation catalyst system of claim 6, wherein the combination of
inorganic co-catalysts further comprises europium.
8. The carbonylation catalyst system of claim 6, wherein the combination of
inorganic co-catalysts further comprises bismuth.
9. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and europium.
10. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and nickel.
11. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and zirconium.
12. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and iron.
13. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and cobalt.
14. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and ruthenium.
15. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and rhodium.
16. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and chromium.
17. The carbonylation catalyst system of claim 1, comprising a catalytic amount of
a combination of inorganic co-catalysts comprising zinc and a substance selected
from the group consisting of copper; copper and titanium; copper and iron; cerium;
manganese; manganese and europium; manganese and bismuth; europium; nickel;
iron; cobalt; ruthenium; rhodium; zirconium; and chromium.
18. The carbonylation catalyst system of claim 17, further comprising an effective
amount of a palladium source.
19. The carbonylation catalyst system of claim 18, wherein the palladium source
is a Pd(II) salt or complex.
20. The carbonylation catalyst system of claim 19, wherein the palladium source
is palladium acetylacetonate.
21. The caibonylation catalyst system of claim 18, wherein fee palladium source
is supported Pd.
22. The carbonylation catalyst system of claim 21, wherein the palladium source
is palladium on carbon.
23. The carbonylation catalyst system of claim 18, furthM- comprising an effective
amount of ahalide composition.
24. The carbonylation catalyst system of claim 23, wherein the halide composition
is tetraethyianimonium bromide.
25. The carbonylation catalyst system of claim 23, wherein the halide composition
is hexaethylguanidinium bromide.
26. The caibonylation catalyst system of claim 18, wherein the molar ratio of zinc
relative to palladium is between 0.1 and 100.
27. A method of carbonylating aromatic hydroxy compounds, said method
comprising the step of:
contacting at least one aromatic hydroxy compound with oxygen and carbon
monoxide in the presence of a carbonylation catalyst system comprising a catalytic
amount of an inorganic co-catalyst comprising zinc.
28. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
copper.
29. The method of claim 28, wherein the combination of inorganic co-catalysts
ftirther comprises titanium.
30. The method of claim 28, wherein the combination of inorganic co-catalysts
further comprises iron.
31. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
cerium.
32. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
manganese.
33. The method of claim 32, wherein the combination of inorganic co-catalysts
fiirther comprises europium.
34. The method of claim 32, wherein the combination of inorganic co-catalysts
fiirther comprises bismuth.
35. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
europium.
36. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
nickel.
37. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
zirconium.
38. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
iron.
39. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
cobalt.
40. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
ruthenium.
41. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
rhodium.
42. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and
chromium.
43. The method of claim 27, wherein the carbonylation catalyst system comprises
a catalytic amount of a combination of inorganic co-catalysts comprising zinc and a
substance selected from the group consisting of copper; copper and titanium; copper
and iron; cerium; manganese; manganese and europium; manganese and bismuth;
europium; nickel; iron; cobalt; ruthenium; rhodium; zirconium; and chromium.
44. The method of claim 43, wherein the carbonylation catalyst system further
comprises an effective amount of a palladium source.
45. The method of claim 44, wherein the palladium source is a Pd(II) salt or
complex.
46. The method of claim 45, wherein the palladium source is palladium
acety lacetonate.
47. The method of claim 44, wherein the palladium source is supported palladium.
48. The method of claim 47, wherein the supported palladium is palladium on
carbon.
49. The method of claim 44, wherein the carbonylation catalyst system further
comprises an effective amount of a halide composition.
50. The method of claim 49, wherein the halide composition is
tetraethylammonium bromide.
51. The method of claim 49, wherein the halide composition is
hexaethylguanidinium bromide.
52. The method of claim 43, wherein the aromatic hydroxy compound is phenol.
53. The method of claim 44, wherein the molar ratio of zinc relative to palladium
is between O.I and 100 at the initiation of the carbonylation.

A method and catalyst system for economically producing aromatic carbonates from
aromatic hydroxy compounds. In one embodiment, the present invention provides a
method of carbonylating aromatic hydroxy compounds by contacting at least one
aromatic hydroxy compound with oxygen and carbon monoxide in the presence of a
carbonylation catalyst system that includes a catalytic amount of an inorganic co-
catalyst containing zinc. In various alternative embodiments, the carbonylation
catalyst system can include an effective amount of a palladium source and an
effective amount of a halide composition. Further alternative embodiments can
include catalytic amounts of various inorganic co-catalyst combinations.