Organic compounds -- part of the class 532-570 series – Organic compounds – Carbonate esters
Reexamination Certificate
2002-04-30
2004-03-02
Rotman, Alan L. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbonate esters
Reexamination Certificate
active
06700008
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to a catalyst composition and method for producing aromatic carbonates through the carbonylation of aromatic hydroxy compounds.
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. Various methods for preparing aromatic carbonates have been previously described in the literature and 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 catalyzed by at least one Group 8, 9, or 10 metal source. Further refinements to the carbonylation catalyst composition include the identification of co-catalysts.
The utility of the carbonylation process is strongly dependent on the number of moles of desired aromatic carbonate produced per mole of Group 8, 9, or 10 metal utilized (i.e. “catalyst turnover number or ‘TON’”). Consequently, much work has been directed to the identification of efficacious catalyst compositions that increase the catalyst turnover number.
Carbonylation catalyst literature lauds the effectiveness of halide salts, particularly bromide salts, in catalyst compositions for improving catalyst TON's. While it is true that catalyst compositions that contain halide salts have historically exhibited high activity, there are drawbacks to using halide in a carbonylation reaction. For example, when used to carbonylate phenol, bromide anions are consumed in the process, forming undesirable brominated byproducts, such as 2- and 4-bromophenols and bromodiphenylcarbonate.
It would be desirable to identify catalyst compositions that would minimize consumption of components or perhaps that would omit components such as halide. It would also be desirable to increase selectivity toward the desired carbonate product and minimizing formation of undesirable halogenated byproducts.
As the demand for high performance plastics has continued to grow, new and improved methods of providing product are needed to supply the market. Consequently, a long felt, yet unsatisfied need exists for new and improved methods and catalyst compositions for producing aromatic carbonates and the like.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method and catalyst composition for producing aromatic carbonates. In one embodiment, the present invention provides a method for carbonylating aromatic hydroxy compounds, comprising the step of contacting at least one aromatic hydroxy compound with oxygen and carbon monoxide in the presence of a carbonylation catalyst composition comprising an effective amount of at least one Group 8, 9, or 10 metal source, an effective amount of at least one inorganic co-catalyst comprising a Group 14 metal source, and an effective amount of at least one salt co-catalyst, wherein the carbonylation catalyst composition is free of a halide source.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is directed to a carbonylation method and catalyst composition for producing aromatic carbonates. The constituents of the carbonylation catalyst composition are defined as “components” irrespective of whether a reaction between the constituents occurs before or during the carbonylation reaction. Thus, the catalyst composition typically includes the components and any reaction products thereof. 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 composition comprising an effective amount of at least one Group 8, 9, or 10 metal source, an effective amount of an inorganic co-catalyst comprising at least one Group 14 element source, and an effective amount of at least one salt co-catalyst, wherein the carbonylation catalyst composition is free of a halide source. Unless otherwise noted, the term “effective amount,” as used herein, includes that amount of a substance capable of yielding the desired aromatic carbonate, or also includes that amount of a substance that increases the selectivity of any one of the starting reagents (e.g. oxygen, carbon monoxide, and aromatic hydroxy compound) towards the desired aromatic carbonate. In another 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 composition that comprises an effective amount of at least one Group 8, 9, or 10 metal source, an effective amount of at least one first inorganic co-catalyst comprising at least one Group 14 element source, an effective amount of at least one second inorganic co-catalyst selected from the group consisting of a Group 4 metal source, a Group 7 metal source, a Group 11 metal source, and a lanthanide element source; and an effective amount of at least one salt co-catalyst, wherein the catalyst composition is free of a halide source. In yet another 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 composition that comprises an effective amount of at least one Group 8, 9, or 10 metal source, an effective amount of at least one first inorganic co-catalyst comprising at least one Group 14 element source, an effective amount of at least one second inorganic co-catalyst selected from the group consisting of Group 4 metal sources, and lanthanide element sources; an effective amount of at least one salt co-catalyst, and an effective amount of at least one base, wherein the catalyst composition is free of a halide source
Any aromatic hydroxy compound, which is convertible to a carbonate ester, is suitable in the present invention. For example, suitable aromatic hydroxy compounds include, but are not limited to, monocyclic, polycyclic or fused polycyclic aromatic monohydroxy or polyhydroxy compounds having from about 6 to about 30, and preferably from about 6 to about 15 carbon atoms. Illustrative examples include but are not limited to phenol, alkylphenols, alkoxyphenols, biphenols, bisphenols, and salicylic acid derivates such as methyl salicylate.
The carbonylation catalyst composition contains at least one catalyst component selected from Group 8, 9, or 10 metal sources. Typical Group 8, 9, or 10 metal sources include ruthenium sources, rhodium sources, palladium sources, osmium sources, iridium sources, platinum sources, and mixtures thereof. The quantity of the Group 8, 9, or 10 metal source is not limited in the process of the present invention. The amount employed should be about 1 gram of Group 8, 9, or 10 metal per 100 grams to, 1,000,000 grams of aromatic hydroxy compound (i.e. about 1 part per million (ppm) to about 10,000 ppm of Group 8, 9, or 10 metal). For example, about 1 ppm to about 1000 ppm of Group 8, 9, or 10 metal is suitable. In one embodiment of the present invention about 1 ppm to about 30 ppm of Group 8, 9, or 10 metal is used. A typical Group 8, 9, or 10 metal source is a palladium source. The palladium source used is typically in the Pd (II) oxidation state at the beginning of the reaction. Alternatively, a palladium compound in either the Pd(0) or Pd(IV) oxidation states can be used. As used herein, the term “compound” includes inorganic, coordination and organometallic complex compounds. The compounds are typically neutral, cationic, or anionic, depending on the charges carried by the central atom and the coordinated ligands. Other common names for these compounds include complex ions (if electrically charged), Werner complexes, and coordination complexes. A Group 8, 9, or 10 metal source can be employed in a homogeneous form that is substantially soluble in the reaction media or in a heterogeneous form which is substantially insoluble in the reaction media, including supported or polymer bound species. Examples of suitable
Johnson Bruce Fletcher
Shalyaev Kirill Vladimirovich
Soloveichik Grigorii Lev
Whisenhunt, Jr. Donald Wayne
Caruso Andrew J.
General Electric Company
Patnode Patrick K.
Rotman Alan L.
Sackey Ebenezer
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