Title:
CRYSTALLIZATION OF ACID DIANHYDRIDE
Document Type and Number:
Japanese Patent JP2000159772
Kind Code:
A
Abstract:
To provide a crystallization process that gives bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic dianhydride of high purity in high yield.
In the production of bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic dianhydride of formula II by reaction of bicyclo[3.3.0]octane-2,4,6,8- tetracarboxylic acid of formula I with acetic anhydride, the concentrate of the reaction mixture after evaporation of acetic anhydride and acid is cooled down by adding a poor solvent of this dianhydride at a temperature from 50°C to its boiling point to crystallize out the objective dianhydride. Then, the collected dianhydride crystals are purified by filtration and isolation.
Inventors:
OTSUKA YOSHIKAZU
KOBAYASHI HIDEKI
NAKAJIMA YASUYUKI
KOBAYASHI HIDEKI
NAKAJIMA YASUYUKI
Application Number:
JP34298398A
Publication Date:
June 13, 2000
Filing Date:
December 02, 1998
Export Citation:
Assignee:
NISSAN CHEMICAL IND LTD
International Classes:
C07D493/08; (IPC1-7): C07D493/08