| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing dicyclohexyl-3,3',4,4'-tetracarboxylic acid isomers which are new raw materials for polyimide resins. SOLUTION: This method for producing trans-dicyclohexyl-3,3',4,4'- tetracarboxylic acids such as (1R,1'S,3R,3'S,4R,4'S)-dicyclohexyl3,3',4,4'- tetracarboxylic acid (trans-DCTA-1), comprising hydrogenating tetramethyl biphenyl-3,3',4,4'-tetracarboxylate, recrystallizing the obtained product to preferentially separate the isomer of cis structure and hydrolyzing the separated isomer in water in an autoclave at 200 to 250 deg.C, while removing the released methanol and water from the reaction system.
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