摘要:
Brominated hydroxyaromatic compounds such as p-bromophenol are prepared by contacting a hydroxyaromatic compound with oxygen and a bromine source such as hydrogen bromide or an alkali metal or alkaline earth metal bromide in an acidic medium, in the presence of elemental copper or a copper compound as catalyst. The brominated product of this reaction may be converted alternately to a dihydroxyaromatic compound such as hydroquinone by hydrolyses, or a dihydroxybiphenyl compound such as 4,4′-dihydroxybiphenyl by reductive coupling.
摘要:
A method for preparing hydroxyaromatic compounds brominated in the para-position, such as p-bromophenol, is disclosed. The method yields overall high process selectivity through isomeric equilibration and separation of the brominated products, thereby eliminating the need for high para selectivity in the products of catalytic oxybromination reactions of hydroxyaromatic compounds using oxygen, a bromine source, and an acidic medium in the presence of a metal catalyst. Furthermore, the invention provides an efficient method for recycling the metal catalyst, as well as reagents used in the bromination, to further reactions.
摘要:
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 a combination of inorganic co-catalysts containing manganese and nickel; manganese and iron; manganese and chromium; manganese and cerium; manganese and europium; manganese, cerium, and europium; manganese, iron, and europium; or manganese and thorium. 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 other inorganic co-catalyst combinations.
摘要:
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 a combination of inorganic co-catalysts containing manganese and nickel; manganese and iron; manganese and chromium; manganese and cerium; manganese and europium; manganese, cerium, and europium; manganese, iron, and europium; or manganese and thorium. 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 other inorganic co-catalyst combinations.
摘要:
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 lead and a catalytic amount of an inorganic co-catalyst containing titanium. 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.
摘要:
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 lead and a catalytic amount of an inorganic co-catalyst containing titanium. 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.
摘要:
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 copper. 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.
摘要:
The present invention is directed to a method for reducing the percent decomposition of an aromatic carbonate in a first reaction mixture comprising the aromatic carbonate, the method comprising the step of adding at least one decomposition-reducing additive to the first reaction mixture, so as to produce a second reaction mixture in which the percent of the aromatic carbonate present in the second reaction mixture after a predetermined amount of time is greater than the percent of the aromatic carbonate that would be present in the first reaction mixture in the absence of adding the decomposition-reducing additive, after the same predetermined amount of time.
摘要:
A method is described for the simultaneous preparation of p-bromophenols and p-benzoquinones, intermediates useful in the preparation of hydroquinones and 4,4′-dihydroxybiphenyls, respectively. Hydroquinones and 4,4′-dihydroxybiphenyls are useful monomers for the preparation of a variety of polymers. The method also comprises reducing the p-benzoquinone to its corresponding hydroquinone in the presence of the p-bromophenol. Limiting the amount of HBr present in the reaction mixture was shown to control the amount of benzoquinone produced. The method also allows for the recycling of many of the reagents used, thereby reducing the cost of producing each monomer.
摘要:
Lead halophenoxides, especially bromophenoxides, are prepared by the reaction of lead(II) oxides with a hydroxyaromatic compound such as phenol and a chloride or bromide salt such as an alkali metal bromide, a tetraalkylammonium bromide or a bexaalkylguanidinium bromide. They are useful in catalyst compositions for the oxidative carbonylation of hydroxyaromatic compounds to diaryl carbonates.