| 摘要 |
PROBLEM TO BE SOLVED: To provide a crystallization process that gives bicyclo[3.3.0]octane-2,4,6,8-tetracarboxylic dianhydride of high purity in high yield. SOLUTION: 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 deg.C to its boiling point to crystallize out the objective dianhydride. Then, the collected dianhydride crystals are purified by filtration and isolation.
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