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AssigneeMitsubishi Gas Chemical Company, Inc.
InventorsShinichi Nagao, Masato Inari, Jitsuo Oishi, Kenji Nakaya, Hiroshi Machida
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A process for producing a high purity aromatic polycarboxylic acid (APA) by purification of a crude APA comprises: (I) aging a slurry of the crude APA in a first dispersion medium at 180 to 300° C. for 10 minutes or longer under stirring; (II) introducing the aged slurry of the APA into a column for substituting dispersion media, bringing the slurry into contact with a second dispersion medium and separating the resultant fluid into a fluid of the first dispersion medium containing impurities and a slurry of the second dispersion medium containing crystals of the high purity APA; and (III) separating the crystals of the high purity APA from the slurry of the second dispersion medium. A high purity APA having excellent hue and particle diameter can be industrially advantageously produced while the construction of the process is simplified and the consumption of energy is decreased.
A process for producing a high purity aromatic polycarboxylic acid selected from the group consisting of naphthalenepolycarboxylic acids and biphenylpolycarboxylic acids by purifying a crude aromatic polycarboxytic acid selected from the group consisting of crude naphthalenepolycarboxylic acids and crude biphenylpolycarboxylic acids, respectively, which comprises:
A process for producing a high purity aromatic polycarboxylic acid selected from the group consisting of naphthalenepolycarboxylic acids and biphenylpolycarboxylic acids by purifying a crude aromatic polycarboxylic acid selected from the group consisting of crude naphthalenepolycarboxylic acids and crude biphenylpolycarboxylic acids, respectively, which comprises:
Dependencies are inferred from the claim text.