Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1993-10-27
1994-10-25
Shippen, Michael L.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
562487, C07C 5116
Patent
active
053591330
ABSTRACT:
Disclosed herein is a process for producing highly purified benzenedicarboxylic acid isomers without an additional catalytic reductive purification step, which comprises (a) an oxidation step wherein xylene isomer is oxidized with molecular oxygen or molecular oxygen containing gas in the presence of a catalyst system composed of cobalt, manganese, bromine and at least one selected from nickel, chromium, zirconium and cerium in lower aliphatic carboxylic acid; and (b) an extraction/post-oxidation step wherein the oxidation product is crystallized to give cake of crude benzenedicarboxylic acid isomer, the cake is reslurried by adding lower aliphatic carboxylic acid solvent thereto followed by heating in order to extract impurities contained therein into the solvent, and the resulting slurry is oxidized with said catalyst system at a temperature of 2.degree.-80.degree. C. lower than that of said heating, each of said oxidation and extraction/post-oxidation being carried out once or twice, provided that any one or both of said steps should be carried out twice. According to the invention, the solvent employed to extract impurities is recycled from the subsequent oxidation steps.
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Goncharova Nadezhda N.
Manzurov Vladimir D.
Nazimok Vladimir F.
Yurjev Valerij P.
Joint-Stock Company of Research and Design Institute of Monomers
Samsung General Chemical Co., Ltd.
Shippen Michael L.
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