Title:
PRODUCTION OF QUINOPHTHALONEDICARBOXYLIC ACID HAVING HIGH PURITY
Document Type and Number:
Japanese Patent JP3471045
Kind Code:
B2
Abstract:
PURPOSE: To obtain quinophthalonedicarboxylic acid having high purity and useful as an intermediate for pigment, etc., by hydrolyzing and neutralizing a specific quinophthalonedicarboxylic acid anhydride with an alkaline compound to obtain a solubilized product, removing insoluble impurities by filtration and adding an acid to precipitate the free acid.
CONSTITUTION: This quinophthalonedicarboxylic acid having high purity and expressed by the formula III can be produced by adding an aqueous solution of an alkaline compound (e.g. sodium hydroxide) to a quinophthalonedicarboxylic acid anhydride expressed by the formula I (X is H, halogen or alkyl), heating the liquid mixture to 50°C after confirming the adjustment of pH to 12.9, stirring for 2hr at 50-52°C to effect the hydrolysis and neutralization of the compound and form a solubilized quinophthalone compound salt expressed by the formula II (Y and Z are cation), removing insoluble impurities from the product by filtration, adding an acid (e.g. sulfuric acid) to adjust the pH to 1.95, heating at 90°C, keeping at the temperature for 2hr, adding water to precipitate crystals, collecting the crystal by filtration and drying the product.
Inventors:
Akira Ogiso
Denmi Misawa
Rihoko Imai
Naoto Ito
Yoshihiro Irisato
Keisuke Takuma
Denmi Misawa
Rihoko Imai
Naoto Ito
Yoshihiro Irisato
Keisuke Takuma
Application Number:
JP19593993A
Publication Date:
November 25, 2003
Filing Date:
August 06, 1993
Export Citation:
Assignee:
Mitsui Chemicals, Inc.
International Classes:
C07D215/20; C09B25/00; (IPC1-7): C07D215/20
Domestic Patent References:
| JP5943086A |
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